Blood pumping device and method of manufacturing a blood pumping device

Abstract

A method of manufacturing a blood pumping device for treating cardiovascular related diseases, the method comprising the steps of: manufacturing an impeller by connecting a material to a structure defining a plurality of helical elongate elements, the invention relates to an impeller comprising a plurality of helical elongate elements attached to a material, such that the plurality of helical elongate elements attached to the material define one or more blades of the impeller, the attachment being performed by immersing at least a portion of the structure in the material when the material is in a liquid state, drying the material while the material is supported by the plurality of helical elongate elements; and during drying of the material, rotating the structure about its longitudinal axis to facilitate formation of a thin film of the material having a substantially uniform thickness within the blades of the impeller. The invention further discloses a blood pumping device.

Description

[0001] Related Applications

[0002] This application is a divisional application of application number 202110905794.6, application date March 13, 2014, and invention name “Blood pump device and method for manufacturing a blood pump”. Technical Field

[0003] Certain applications of the present invention generally relate to medical devices. Specifically, certain applications of the present invention relate to devices or methods associated with placing a pump in one or more kidneys of a subject. Background Art

[0004] It is common for cardiac dysfunction or congestive heart failure to develop into renal insufficiency, which in turn leads to the development or worsening of symptoms of congestive heart failure. Typically, systolic and / or diastolic cardiac insufficiency causes systemic venous congestion that produces increased renal venous and interstitial pressures. The increase in pressure is caused by an increase in fluid retention in the body due to both renal insufficiency and renal neuroendocrine activation, both of which typically develop as a result of the increased renal venous and interstitial pressures. The resulting fluid retention, through a blood volume overload at the heart and / or through increased systemic resistance, causes the development or worsening of congestive heart failure. Similarly, it is common for renal insufficiency and / or renal neurohormonal activation to develop into cardiac insufficiency and / or congestive heart failure. In which cardiac insufficiency and / or congestive heart failure leads to renal dysfunction and / or renal neurohormonal activation, or in which renal dysfunction and / or renal neurohormonal activation leads to cardiac dysfunction and / or congestive heart failure, each dysfunction leads to aggravation of the other, and this pathophysiological cycle is known as cardio-renal syndrome.

[0005] Increased renal venous pressure has been shown experimentally to cause azotemia, and a decrease in glomerular filtration rate, renal blood flow, urine volume, and sodium excretion. It has also been shown to increase plasma renin and aldosterone, and protein excretion. Venous congestion can also contribute to anemia through three different pathways: a decrease in erythropoietin production in the kidneys, hemodilution through fluid retention, and inflammatory responses leading to decreased gastrointestinal iron uptake.

[0006] Mechanistically, increased renal venous pressure may result in increased intracapsular pressure and subsequent increase in interstitial peritubular pressure. Increased peritubular pressure may affect tubular function (reduced sodium excretion) and reduce glomerular filtration by increasing the pressure in the Bowman capsule.

[0007] In patients with heart failure, increased renal venous pressure can result not only from increased central venous (right atrium) pressure, but also from intra-abdominal fluid accumulation (ascites) exerting pressure directly on the kidneys. Reducing intra-abdominal pressure in patients with heart failure by removing fluid (e.g., by paracentesis, and / or ultrafiltration) has been shown to reduce plasma creatinine levels.

[0008] Particularly in patients with heart failure, increased venous return due to activation of the "leg muscle pump" during physical activity such as walking may increase systemic venous pressure and may result in reflux into the renal veins.

[0009] Increased venous return resulting from the "leg muscle pump" during physical activity such as walking may cause systemic venous pressure, particularly in heart failure patients, and may result in reflux into the renal veins. Summary of the invention

[0010] According to certain applications of the present invention, in order to provide acute treatment to a subject suffering from cardiac insufficiency, congestive heart failure, low renal blood flow, high renal vascular resistance, hypertension and renal insufficiency, a blood pump includes an impeller placed in a renal vein of a subject and activated to pump blood from the renal vein to the vena cava of the subject. For example, the impeller can be placed in multiple renal veins of the subject for a period of more than one hour (e.g., more than one day), less than one week (e.g., less than four days), and / or between one hour and one week (e.g., between one day and four days).

[0011] The pump is typically configured to pump blood in a downstream direction to reduce pressure in the renal veins. Typically, due to the reduction in pressure in the renal veins caused by the pumping of blood in the downstream direction, perfusion of the kidney increases. In turn, due to the increased blood flow into the renal veins, this may cause the pressure in the multiple renal veins to rise relative to the pressure in the multiple renal veins immediately after the start of the pumping. Typically, even after perfusion of the kidney increases, the pump is configured to maintain the pressure in the renal veins at a lower value compared to the pressure in the renal veins before the start of the pumping.

[0012] Typically, the renal vein of the subject is protected from injury by the impeller by placing a cover within the renal vein and surrounding the impeller, the cover separating a wall of the renal vein from the impeller. For some applications, the cover and the impeller are engaged with each other by an engagement mechanism, so that in response to the cover becoming radially compressed, the impeller becomes radially compressed so that the cover maintains the separation between the wall of the renal vein and the impeller.

[0013] According to some applications, a pump and an occlusion member (e.g., a valve) are placed in a renal vein of a subject to provide acute treatment for heart failure, congestive heart failure, low renal blood flow, high renal vascular resistance, hypertension, and renal insufficiency. For example, the pump and the occlusion member may be placed in the renal vein of the subject for a period of more than one hour (e.g., more than one day), less than one week (e.g., less than four days), and / or between one hour and one week (e.g., between one day and four days).

[0014] The occlusion member is configured to occlude the renal vein at an occlusion. The pump is configured to pump blood in a downstream direction from a location on the upstream side of the occlusion member to a location on the downstream side of the occlusion member. In doing so, the pump reduces pressure within the renal vein. The occlusion member is configured to protect the renal vein from blood backflow from the vena cava into the renal vein.

[0015] Typically, due to the decrease in pressure in the renal vein caused by the pumping of the blood in the downstream direction, perfusion of the kidney increases. In turn, due to the increased blood flow into the renal vein, this may cause the pressure in the multiple renal veins to rise relative to the pressure in the multiple renal veins immediately after the start of the pumping. Typically, the pump is configured to maintain the pressure in the renal vein at a lower value even after the perfusion of the kidney increases compared to the pressure in the renal vein before the start of the pumping.

[0016] According to some applications of the present invention, a blood-impermeable sleeve is placed within the vena cava of the subject so that a downstream end of the sleeve is connected to the wall of the vena cava at a first location downstream of all of the subject's renal veins, and so that an upstream end of the sleeve is connected to the wall of the vena cava at a second location upstream of all of the subject's renal veins. Typically, a connection structure, such as a rigid connection structure (e.g., a stent), is configured to connect the upstream and downstream ends of the sleeve to the vena cava.

[0017] A pump draws blood from a location outside the sleeve to a location inside the sleeve (e.g., a location within the vena cava upstream or downstream of the sleeve). Thus, the pump draws blood outside the subject's renal veins and into the subject's vena cava. The sleeve prevents backflow of blood from the vena cava to the renal veins.

[0018] Therefore, according to some applications of the present invention, there is provided a method comprising:

[0019] Identifying a subject suffering from a condition selected from the group consisting of: cardiac insufficiency, congestive heart failure, decreased renal blood flow, increased renal vascular resistance, hypertension, and renal insufficiency; and

[0020] In response to the above situation, the blood pressure in a renal vein of the subject is reduced by placing an impeller in the renal vein of the subject and activating the impeller to pump blood from the renal vein to a vena cava of the subject.

[0021] For some applications, activating the impeller to pump blood from the renal vein to the vena cava includes increasing a rate of blood flow from the renal vein into the vena cava without causing a substantial change in a direction of blood flow relative to a direction of blood flow from the renal vein into the vena cava when the pump is not activated.

[0022] For some applications, activating the impeller to pump blood from the renal vein to the vena cava includes activating the impeller to pump blood from the renal vein directly to a portion of the vena cava adjacent to the renal vein.

[0023] For some applications, activating the impeller to pump blood from the renal vein to the vena cava includes activating the impeller to pump blood from the renal vein to the vena cava without moving blood from a venous system of the subject into a non-venous container.

[0024] For some applications, the step of placing the impeller within the renal vein includes: placing the impeller into the renal vein and having a cover surrounding the impeller, wherein the cover separates an inner wall of the renal vein from the impeller to protect the subject's renal vein from damage by the impeller.

[0025] For some applications, the step of placing the impeller with the cover in the renal vein includes: placing the impeller into the renal vein and setting the cover around the impeller, the cover and the impeller are engaged with each other by a coupling mechanism, so that in response to the cover becoming radially compressed, the impeller can become axially elongated so that the cover maintains separation between the wall of the renal vein and the impeller.

[0026] According to some embodiments of the present invention, there is further provided an apparatus comprising:

[0027] An impeller comprising:

[0028] an impeller frame including a proximal portion and a distal portion and a plurality of helical elongated elements winding from the proximal portion to the distal portion; and

[0029] A material is connected to the plurality of helical elongated elements such that the plurality of helical elongated elements having the material connected thereto define at least one blade of the impeller.

[0030] For some applications, the impeller includes a biocompatible impeller configured for insertion into a blood vessel of a subject.

[0031] For some applications, the plurality of elongated elements comprises: a plurality of spiral ribbons.

[0032] For some applications, at least one of the plurality of helical elongated elements has a variable pitch, wherein the pitch of the at least one of the plurality of helical elongated elements varies along a length of the helical elongated element.

[0033] For some applications, the impeller is configured to be placed within a blood vessel of a subject and to pump blood through the blood vessel by rotating relative to the blood vessel, and the device further includes a radially expandable cover configured to be positioned between the impeller and an inner wall of the blood vessel and to separate the inner wall of the blood vessel from the impeller.

[0034] For some applications, the proximal portion and the distal portion include: a proximal ring and a distal ring.

[0035] For some applications, at least one of the proximal portion and the distal portion defines a notch in an edge thereof, the notch being configured to facilitate coupling of the material to the plurality of helical elongated elements.

[0036] For some applications, the impeller further includes: a plurality of sutures tied around the plurality of helical elongated elements, the plurality of sutures configured to facilitate attachment of the material to the plurality of helical elongated elements.

[0037] For some applications, the plurality of helical elongated elements includes three helical elongated elements winding from the proximal portion to the distal portion.

[0038] For some applications, when the impeller is in its unrestrained configuration, a length of each of the plurality of helical elongated elements measured along a longitudinal axis of the impeller is greater than 5 mm. For some applications, when the impeller is in its unrestrained configuration, a length of each of the plurality of helical elongated elements measured along a longitudinal axis of the impeller is less than 14 mm.

[0039] For some applications, when the impeller is in its unrestrained configuration, a span width of the impeller in a direction perpendicular to a longitudinal axis of the impeller is greater than 8 mm. For some applications, the span width of the impeller is greater than 10 mm. For some applications, the span width of the impeller is less than 15 mm. For some applications, the span width of the impeller is less than 12 mm.

[0040] For some applications, the plurality of helical elongated elements include two helical elongated elements winding from the proximal portion to the distal portion.

[0041] For some applications, the radius of each of the two helical elongated elements is within 20% of the other. For some applications, the radius of each of the two helical elongated elements is similar to the other. For some applications, the pitch of each of the two helical elongated elements is within 20% of the other. For some applications, the pitch of each of the two helical elongated elements is similar to the other. For some applications, the longitudinal axes of each of the two helical elongated elements are parallel to each other and to a longitudinal axis of the impeller.

[0042] For some applications, the material comprises: a continuous film of material supported by the plurality of helical elongated elements.

[0043] For some applications, each of the plurality of helical elongated elements defines more than one eighth of a winding of a helix. For some applications, each of the plurality of helical elongated elements defines less than one half of a winding of a helix.

[0044] For some applications:

[0045] The plurality of helical elongated elements define a proximal end and a distal end thereof;

[0046] The plurality of helical elongated elements are configured to support the material between the proximal ends and the distal ends of the plurality of helical elongated elements; and

[0047] The impeller does not include any additional supports for supporting the material between the proximal ends and the distal ends of the plurality of helical elongated elements.

[0048] For some applications, the impeller is configured such that rotational motion is imparted from the proximal portion of the impeller to the distal portion of the impeller substantially solely through the plurality of helical elongated elements of the impeller.

[0049] For some applications, the impeller can be configured to be radially compressible to a smaller diameter by not including any additional supports for supporting the material between the proximal and distal ends of the plurality of helical elongated elements than would be assumed if the impeller included any additional supports for supporting the material between the proximal and distal ends of the plurality of helical elongated elements.

[0050] For some applications, the impeller is configured to be more flexible by not including any additional supports for supporting the material between the proximal ends and the distal ends of the plurality of helical slender elements than would be assumed if the impeller included any additional supports for supporting the material between the proximal ends and the distal ends of the plurality of helical slender elements.

[0051] For some applications, by not including any additional supports for supporting the material between the proximal and distal ends of the plurality of helical elongated elements, the impeller can be configured such that a predetermined amount of force required to axially elongate the impeller can be less than would be required assuming the impeller included any additional supports for supporting the material between the proximal and distal ends of the plurality of helical elongated elements.

[0052] According to some applications of the present invention, there is further provided a method comprising the steps of:

[0053] An impeller is manufactured by the following steps:

[0054] cutting a tube so that the cut tube defines a structure having a first end portion and a second end portion at a proximal end and a distal end of the structure, the first end portion and the second end portion being interconnected by a plurality of elongated members;

[0055] axially compressing the structure, causing the plurality of elongated elements to radially expand and form a plurality of helical elongated elements; and

[0056] A material is attached to the plurality of helical elongated elements such that the plurality of helical elongated elements having the material attached thereto define at least one blade of the impeller.

[0057] For some applications, cutting the tube includes laser cutting the tube.

[0058] For some applications, the step of manufacturing the impeller includes manufacturing a biocompatible impeller configured for insertion into a blood vessel of a subject.

[0059] For some applications, cutting the tube includes cutting the tube so that the cut tube defines a structure having a first end portion and a second end portion at a proximal end and a distal end of the structure, the first end portion and the second end portion being interconnected by a plurality of strips.

[0060] For some applications, radially expanding the elongated elements to form a plurality of helical elongated elements includes providing at least one of the elongated elements with a variable pitch, the pitch of the at least one of the elongated elements varying along a length of the helical elongated element.

[0061] For some applications, the step of cutting the tube so that the cut tube defines a structure having a first end portion and a second end portion at a proximal end and a distal end of the structure includes cutting the tube so that the cut tube defines a structure having a first ring and a second ring at a proximal end and a distal end of the structure.

[0062] For some applications, cutting the tube further includes forming a notch in an edge of at least one of the first end portion and the second end portion, the notch configured to facilitate coupling of the material to the plurality of helical elongated elements.

[0063] For some applications, the method further includes tying a plurality of sutures around the plurality of helical elongated elements, the plurality of sutures configured to facilitate attachment of the material to the plurality of helical elongated elements.

[0064] For some applications, the step of cutting the tube includes cutting the tube so that the cut tube defines a structure having a first end portion and a second end portion at a proximal end and a distal end of the structure, the first end portion and the second end portion being interconnected by three elongated elements, and wherein the step of causing the plurality of elongated elements to radially expand and form a plurality of helical elongated elements includes forming the plurality of elongated elements into three helical elongated elements.

[0065] For some applications, the step of cutting the tube includes cutting the tube so that the structure has a length measured along a longitudinal axis of the structure greater than 15 mm when no axial compression is applied to the structure. For some applications, the step of cutting the tube includes cutting the tube so that the length of the structure measured along a longitudinal axis of the structure is less than 25 mm when no axial compression is applied to the structure. For some applications, the step of cutting the tube includes cutting the tube so that each of the plurality of elongated elements has a length measured along a longitudinal axis of the structure greater than 14 mm when no axial compression is applied to the structure. For some applications, cutting the tube includes cutting the tube so that each of the plurality of elongated elements has a length measured along a longitudinal axis of the structure less than 22 mm when no axial compression is applied to the structure.

[0066] For some applications, the step of axially compressing the structure includes axially compressing the structure so that the structure defines a length measured along a longitudinal axis of the structure that is greater than 8 mm. For some applications, the step of axially compressing the structure includes axially compressing the structure so that the length defined by the structure measured along the longitudinal axis of the structure is less than 18 mm. For some applications, axially compressing the structure includes axially compressing the structure so that each of the plurality of elongated elements defines a length measured along a longitudinal axis of the structure that is greater than 5 mm. For some applications, axially compressing the structure includes axially compressing the structure so that each of the plurality of elongated elements measured along the longitudinal axis of the structure is less than 14 mm.

[0067] For some applications, the step of axially compressing the structure includes axially compressing the structure so that a span width of the structure in a direction perpendicular to a longitudinal axis of the structure is greater than 8 mm. For some applications, the step of axially compressing the structure includes axially compressing the structure so that the span width of the structure is greater than 10 mm. For some applications, the step of axially compressing the structure includes axially compressing the structure so that the span width of the structure is greater than 15 mm. For some applications, the step of axially compressing the structure includes axially compressing the structure so that the span width of the structure is less than 12 mm.

[0068] For some applications, the step of connecting the material to the plurality of helical elongated elements comprises: dipping at least a portion of the structure into the material while the material is in a liquid state, and drying the material while the material is supported by the plurality of helical elongated elements. For some applications, the step of drying the material comprises: curing the material.

[0069] For some applications, the step of cutting the tube includes cutting the tube so that the cut tube defines a structure having a first end portion and a second end portion at a proximal end and a distal end of the structure, the first end portion and the second end portion being interconnected by two elongated elements, and wherein the step of radially expanding the plurality of elongated elements and forming a plurality of helical elongated elements includes forming the plurality of elongated elements into two helical elongated elements.

[0070] For some applications, when the material is supported by the plurality of helical elongated elements, drying the material includes forming the material into a continuous film between the plurality of helical elongated elements, the continuous film being supported by the plurality of helical elongated elements.

[0071] For some applications, cutting the tube includes cutting the tube so that the cut tube defines a structure having a first end portion and a second end portion at a proximal end and a distal end of the structure, the first end portion and the second end portion being interconnected by two elongated elements, and wherein radially expanding the elongated elements and forming a plurality of helical elongated elements includes forming the elongated elements into two helical elongated elements.

[0072] For some applications, the step of forming the plurality of elongated elements into two spiral elongated elements includes forming the plurality of elongated elements into two spiral elongated elements both starting from the first end portion and terminating at the second end portion, the radius of the plurality of spiral elongated elements being similar to one another. For some applications, the step of forming the plurality of elongated elements into two spiral elongated elements includes forming the plurality of elongated elements into two spiral elongated elements both starting from the first end portion and terminating at the second end portion, the radius of the plurality of spiral elongated elements being within 20% of one another.

[0073] For some applications, forming the plurality of elongated elements into two helical elongated elements includes forming the plurality of elongated elements into two helical elongated elements, both of which start at the first end portion and terminate at the second end portion, the pitch of the plurality of helical elongated elements being similar to one another. For some applications, forming the plurality of elongated elements into two helical elongated elements includes forming the plurality of elongated elements into two helical elongated elements, both of which start at the first end portion and terminate at the second end portion, the pitch of the plurality of helical elongated elements being within 20% of one another.

[0074] For some applications, forming the plurality of elongated elements into two helical elongated elements includes forming the plurality of elongated elements into two helical elongated elements, wherein longitudinal axes of the two helical elongated elements are parallel to each other and to a longitudinal axis of the impeller.

[0075] For some applications, the step of forming the plurality of elongated elements into two helical elongated elements includes forming the plurality of elongated elements into two helical elongated elements, each of the helical elongated elements defining more than one eighth of a winding of a helix. For some applications, the step of forming the plurality of elongated elements into two helical elongated elements includes forming the plurality of elongated elements into two helical elongated elements, each of the helical elongated elements defining less than one half of a winding of a helix.

[0076] For some applications, the step of cutting the tube includes cutting the tube so that the cut tube defines a structure having a first ring and a second ring at a proximal end and a distal end of the structure, and so that the first end and the second end of each of the plurality of elongated elements are disposed at an angle relative to the periphery of the first ring and the second ring, the angle being greater than 50 degrees. For some applications, the step of cutting the tube includes cutting the tube so that the first end and the second end of each of the plurality of elongated elements are disposed at an angle relative to the periphery of the first ring and the second ring, the angle being greater than 70 degrees. For some applications, the step of cutting the tube includes cutting the tube so that the first end and the second end of each of the plurality of elongated elements are disposed at an angle relative to the periphery of the first ring and the second ring, the angle being greater than 90 degrees.

[0077] For some applications, the step of cutting the tube includes cutting the tube so that the cut tube defines a structure having a first ring and a second ring at a proximal end and a distal end of the structure, and thereby the first end and the second end of each of the plurality of elongated elements are disposed at an angle relative to the periphery of the first ring and the second ring, the angle being less than 180 degrees. For some applications, the step of cutting the tube includes cutting the tube so that the first end and the second end of each of the plurality of elongated elements are disposed at an angle relative to the periphery of the first ring and the second ring, the angle being less than 150 degrees. For some applications, the step of cutting the tube includes cutting the tube so that the first end and the second end of each of the plurality of elongated elements are disposed at an angle relative to the periphery of the first ring and the second ring, the angle being less than 110 degrees.

[0078] For some applications, the step of connecting the material to the plurality of helical elongated elements includes connecting the material to the plurality of helical elongated elements so that the material between the proximal ends and the distal ends of the plurality of helical elongated elements is supported by the plurality of helical elongated elements and there are no additional supports between the proximal ends and the distal ends of the plurality of helical elongated elements for supporting the material.

[0079] For some applications, the step of connecting the material to the plurality of helical elongated elements, without any additional support positioned between the proximal and distal ends of the plurality of helical elongated elements for supporting the material, includes configuring the impeller so that rotational motion is transmitted from the proximal portion of the impeller to the distal portion of the impeller substantially solely through the plurality of helical elongated elements of the impeller.

[0080] For some applications, the step of connecting the material to the plurality of helical elongated elements without any additional support for supporting the material between the proximal and distal ends of the plurality of helical elongated elements includes configuring the impeller to be radially compressible to a smaller diameter than would be the case if the impeller included an additional support for supporting the material between the proximal and distal ends of the plurality of helical elongated elements.

[0081] For some applications, the step of connecting the material to the plurality of helical elongated elements without any additional support for supporting the material between the proximal and distal ends of the plurality of helical elongated elements includes configuring the impeller to be more flexible than would be the case if the impeller included an additional support for supporting the material between the proximal and distal ends of the plurality of helical elongated elements.

[0082] For some applications, the step of connecting the material to the plurality of helical elongated elements without any additional support positioned between the proximal and distal ends of the plurality of helical elongated elements for supporting the material includes configuring the impeller so that a predetermined amount of force required to axially elongate the impeller is less than would be required assuming that the impeller included an additional support positioned between the proximal and distal ends of the plurality of helical elongated elements for supporting the material.

[0083] According to some applications of the present invention, there is also provided a device comprising:

[0084] an impeller configured to draw a fluid by rotating in a radially expanded configuration;

[0085] a radially expandable shroud disposed about the impeller so that the impeller is separated from an inner surface of the shroud in a radially expanded configuration of the impeller and the shroud; and

[0086] An engagement mechanism is configured to engage the impeller relative to the cover so that in response to the cover becoming radially compressed, the engagement mechanism axially elongates the impeller to maintain the impeller separated from the inner surface of the cover.

[0087] For some applications:

[0088] The shroud and the impeller define an axially elongated configuration thereof, wherein the shroud is configured to receive the impeller within the shroud while the impeller is in its axially elongated configuration; and

[0089] The cover includes a plurality of struts, at least some of the struts including: portions thereof that undulate at least when the cover is in the radially expanded configuration of the cover;

[0090] An extent of undulation of the undulating portions of the struts when the cover is in its radially expanded configuration is greater than an extent of undulation of the undulating portions of the struts when the cover is in its axially elongated configuration.

[0091] For some applications, the engagement mechanism is configured to allow rotation of the impeller while the cover is maintained in a rotationally fixed position.

[0092] For some applications, the engagement mechanism is configured to axially lengthen the impeller by imparting longitudinal movement of the impeller caused by longitudinal movement of the shroud in response to the shroud becoming radially compressed.

[0093] For some applications, the impeller includes: a biocompatible impeller configured to be placed within a blood vessel and to pump blood through the blood vessel by rotation, and wherein the cover is configured to be disposed between the impeller and an inner wall of the blood vessel and to separate the blood vessel wall from the impeller.

[0094] For some applications, the cover includes a plurality of struts configured to define a plurality of cells, and wherein the cover is configured to separate the vessel wall from the impeller even if the vessel wall protrudes through a cell of the cover.

[0095] For some applications:

[0096] The impeller is connected to the housing so that a longitudinal axis of the impeller is aligned with a longitudinal axis of the housing; and

[0097] The cover defines a central portion thereof having a generally cylindrical shape, and an outer surface of the cover at the generally cylindrical portion of the cover is parallel to the longitudinal axis of the cover.

[0098] For some applications, the impeller is configured to be placed in a blood vessel and to pump the blood through the blood vessel by rotating, and wherein the cover is configured to be disposed between the impeller and an inner wall of the blood vessel and to separate the inner wall of the blood vessel from the impeller.

[0099] For some applications, the cover is configured to expand radially within the blood vessel so that the outer surface of the cover at the generally cylindrical portion of the cover engages the inner wall of the blood vessel, and the cover becomes oriented toward the interior of the blood vessel so that the longitudinal axis of the cover is parallel to a local longitudinal axis of the blood vessel.

[0100] According to some applications of the present invention, there is further provided a method comprising:

[0101] Placing within a blood vessel of a subject:

[0102] an impeller configured, in a radially expanded configuration thereof, to pump blood through the blood vessel by rotation; and

[0103] a radially expandable shroud disposed around the impeller;

[0104] radially expanding the cover and the impeller within the blood vessel so that the impeller is separated from an inner wall of the blood vessel by the cover;

[0105] The impeller is engaged relative to the cover so that, in response to the cover becoming radially compressed, the impeller is axially elongated to maintain the impeller spaced from the inner wall of the blood vessel; and

[0106] A control unit is operated to pump blood through the blood vessel by rotating the impeller.

[0107] For some applications, the blood vessel includes: a renal vein, and wherein operating the control unit to pump blood through the blood vessel includes operating the control unit to pump blood away from a kidney of the subject and toward a vena cava of the subject.

[0108] For some applications, the method further includes operating the control unit to:

[0109] measuring pressure within a blood vessel of the subject at a first location within the blood vessel upstream of the impeller and at a second location within the blood vessel downstream of the impeller; and

[0110] The rotation of the impeller is controlled in response to the pressure measured at the first location and the second location.

[0111] For some applications:

[0112] The step of placing the cover and the impeller in the blood vessel comprises: placing the cover and the impeller in the blood vessel when the cover and the impeller are in their axially elongated configurations; and when the cover is in its axially elongated configuration, the cover contains the impeller in the cover while the impeller is in its axially elongated configuration;

[0113] The cover comprises a cover defining a plurality of struts, at least some of the struts comprising: portions thereof that undulate at least when the cover is in the radially expanded configuration of the cover; and

[0114] The step of radially expanding the cover includes radially expanding the cover so that a degree of undulation of the undulating portions of the struts becomes greater than a degree of undulation of the undulating portions of the struts when the cover is in its axially elongated configuration.

[0115] For some applications, operating the control unit to rotate the impeller includes operating the control unit to rotate the impeller while the cover is maintained in a rotationally fixed position.

[0116] For some applications, the shield includes: a plurality of struts configured to define a plurality of cells, and wherein the step of radially expanding the shield includes: separating the vessel wall from the impeller, ie, causing the vessel wall to protrude through a cell of the shield by radially expanding the shield.

[0117] For some applications:

[0118] The step of placing the impeller and the cover into the blood vessel comprises: placing the impeller and the cover into the blood vessel, the impeller being connected to the cover so that a longitudinal axis of the impeller is aligned with a longitudinal axis of the cover;

[0119] The cover includes a cover defining a central portion thereof having a generally cylindrical shape, an outer surface of the cover at the generally cylindrical portion of the cover being parallel to the longitudinal axis of the cover; and

[0120] The step of radially expanding the cover within the blood vessel includes radially expanding the cover within the blood vessel so that the outer surface of the cover at the generally cylindrical portion of the cover engages the inner wall of the blood vessel, the cover thereby becoming oriented within the blood vessel so that a longitudinal axis of the cover is parallel to a local longitudinal axis of the blood vessel.

[0121] For some applications:

[0122] In the absence of the cover, the blood vessel has a predetermined diameter;

[0123] The step of radially expanding the cage includes: widening a portion of the blood vessel such that a diameter of the portion of the blood vessel is greater than the predetermined diameter; and

[0124] The step of radially expanding the impeller includes radially expanding the impeller so that a span width of the impeller is at least the same as the predetermined diameter.

[0125] For some applications, the method further includes: operating the control unit to:

[0126] measuring flow through the blood vessel; and

[0127] The rotation of the impeller is controlled in response to the measured flow.

[0128] For some applications, the step of operating the control unit to measure flow through the blood vessel includes: operating the control unit to measure blood flow through a thermal flow sensor disposed in a housing, the housing being configured such that a direction of blood flow through the housing is substantially parallel to a local longitudinal axis of the blood vessel.

[0129] According to some applications of the present invention, there is also provided a device comprising:

[0130] a radially expandable impeller configured to draw a fluid by rotating when in a radially expanded configuration;

[0131] a radially expandable shroud disposed about the impeller such that the impeller is spaced from an inner surface of the shroud in a radially expanded configuration of the impeller and the shroud;

[0132] The impeller is connected to the cover so that a longitudinal axis of the impeller is aligned with a longitudinal axis of the cover; and

[0133] The cover defines a central portion thereof having a generally cylindrical shape, and an outer surface of the cover at the generally cylindrical portion of the cover is parallel to the longitudinal axis of the cover.

[0134] For some applications:

[0135] The shroud and the impeller define an axially elongated configuration thereof, wherein when the shroud is in its axially elongated configuration, the shroud is configured to accommodate the impeller within the shroud while the shroud is in its axially elongated configuration; and

[0136] The cover includes a plurality of struts, at least some of the struts including: portions thereof that undulate at least when the cover is in the radially expanded configuration of the cover,

[0137] An extent of undulation of the undulating portions of the struts when the cover is in its radially expanded configuration is greater than an extent of undulation of the undulating portions of the struts when the cover is in its axially elongated configuration.

[0138] For some applications:

[0139] The impeller defines a proximal ring and a distal ring located at a proximal end and a distal end thereof respectively;

[0140] The cover defines a proximal ring and a distal ring located at a proximal end and a distal end thereof, respectively;

[0141] The impeller passes through:

[0142] The proximal rings of the impeller and the cover are placed on a first support member so that the proximal rings of the impeller and the cover are aligned with each other; and

[0143] The distal rings of the impeller and the cover are placed on a second support member so that the distal rings of the impeller and the cover are aligned with each other;

[0144] The cover is connected so that the longitudinal axis of the impeller is aligned with the longitudinal axis of the cover.

[0145] For some applications, the apparatus further includes an engagement mechanism configured to engage the impeller relative to the cover, such that in response to the cover becoming radially compressed, the engagement mechanism axially elongates the impeller, thereby maintaining the impeller separated from the inner surface of the cover.

[0146] For some applications, the engagement mechanism is configured to allow rotation of the impeller while the cover is maintained in a rotationally fixed position.

[0147] For some applications, the engagement mechanism is configured to axially lengthen the impeller by imparting longitudinal movement of the impeller caused by longitudinal movement of the shroud in response to the shroud becoming radially compressed.

[0148] For some applications, the impeller is a biocompatible impeller configured to be placed within a blood vessel and to pump blood through the blood vessel by rotation, and wherein the shield is configured to be disposed between the impeller and an inner wall of the blood vessel and to separate the blood vessel wall from the impeller.

[0149] For some applications, the cover includes a plurality of struts configured to define a plurality of cells, and wherein the cover is configured to separate the vessel wall from the impeller even if the vessel wall protrudes through a cell of the cover.

[0150] For some applications, the impeller is a biocompatible impeller configured to be placed within a blood vessel and to pump blood through the blood vessel by rotation, and wherein the cover is configured to be disposed between the impeller and an inner wall of the blood vessel to separate the blood vessel wall from the impeller.

[0151] For some applications, the cover is configured to expand radially within the blood vessel so that the outer surface of the cover at the generally cylindrical portion of the cover engages the inner wall of the blood vessel, the cover thereby becoming oriented toward the interior of the blood vessel so that the longitudinal axis of the cover is parallel to a local longitudinal axis of the blood vessel.

[0152] According to some applications of the present invention, there is also provided a method comprising:

[0153] Placing within a blood vessel of a subject:

[0154] an impeller configured to pump blood through the blood vessel by rotation when in a radially expanded configuration; and

[0155] a radially expandable shroud disposed about the impeller, the impeller being connected to the shroud such that a longitudinal axis of the impeller is aligned with a longitudinal axis of the shroud, and the shroud defines a central portion thereof having a generally cylindrical shape, an outer surface of the shroud at the generally cylindrical portion of the shroud being parallel to the longitudinal axis of the shroud;

[0156] radially expanding the cage within the blood vessel so that:

[0157] separating the impeller from an inner wall of the blood vessel by the cover; and

[0158] The outer surface of the cover at the generally cylindrical portion of the cover is connected to the inner wall of the blood vessel, the cover being oriented inwardly of the blood vessel so that a longitudinal axis of the cover is parallel to a partial longitudinal axis of the blood vessel; and

[0159] A control unit is operated to pump blood through the blood vessel by rotating the impeller.

[0160] For some applications, the method further includes: operating the control unit to:

[0161] measuring pressure within a blood vessel of the subject at a first location within the blood vessel upstream of the impeller and at a second location within the blood vessel downstream of the impeller; and

[0162] The rotation of the impeller is controlled in response to the pressure measured at the first location and the second location.

[0163] For some applications:

[0164] In the absence of the cover, the blood vessel has a predetermined diameter;

[0165] The step of radially expanding the cage includes: widening a portion of the blood vessel such that a diameter of the portion of the blood vessel is greater than the predetermined diameter; and

[0166] The step of radially expanding the impeller includes radially expanding the impeller so that a span width of the impeller is at least the same as the predetermined diameter.

[0167] For some applications, the method further comprises: operating the control unit to:

[0168] measuring flow through the blood vessel; and

[0169] The rotation of the impeller is controlled in response to the measured flow.

[0170] For some applications, the step of operating the control unit to measure flow through the blood vessel includes: operating the control unit to measure blood flow via a thermal flow sensor disposed within a housing, the housing being configured such that a direction of blood flow through the housing is substantially parallel to the local longitudinal axis of the blood vessel.

[0171] According to some applications of the present invention, there is also provided a device comprising:

[0172] a radially expandable impeller configured to draw a fluid by rotation when in a radially expanded configuration; and

[0173] a radially expandable shroud disposed about the impeller so as to separate the impeller from an inner surface of the shroud in a radially expanded configuration of the impeller and the shroud;

[0174] The shroud and the impeller define an axially elongated configuration thereof, wherein when the shroud is in its axially elongated configuration, the shroud is configured to accommodate the impeller within the shroud while the impeller is in its axially elongated configuration;

[0175] The cover includes a plurality of struts, at least some of the struts including: portions thereof that undulate at least when the cover is in the radially expanded configuration of the cover; and

[0176] An extent of undulation of the undulating portions of the struts when the cover is in its radially expanded configuration is greater than an extent of undulation of the undulating portions of the struts when the cover is in its axially elongated configuration.

[0177] For some applications, for each of the plurality of struts comprising the plurality of undulating portions, the strut is configured to:

[0178] a shortest distance from a first longitudinal end of the strut to a second longitudinal end of the strut when the cover is in its axially elongated configuration;

[0179] a shortest distance from a first longitudinal end of the strut to a second longitudinal end of the strut when the cover is in its radially expanded configuration;

[0180] The ratio between the two is greater than 1.05:1.

[0181] For some applications, the ratio is less than 1.4: 1. For some applications, the ratio is greater than 1.15: 1. For some applications, the ratio is greater than 1.2:1.

[0182] For some applications, the apparatus further includes an engagement mechanism configured to engage the impeller relative to the cover so that the impeller is axially stretched in response to the cover becoming radially compressed to maintain the impeller separated from the inner surface of the cover.

[0183] For some applications, the engagement mechanism is configured to allow rotation of the impeller while the cover is maintained in a rotationally fixed position.

[0184] For some applications, the engagement mechanism is configured to axially lengthen the impeller by imparting longitudinal movement of the impeller caused by longitudinal movement of the shroud in response to the shroud becoming radially compressed.

[0185] For some applications:

[0186] The housing and the impeller are biocompatible and configured for insertion between a blood vessel when the impeller is disposed within the housing and when the housing and the impeller are in their axially elongated configurations;

[0187] The impeller is configured to expand radially within the blood vessel to pump blood through the blood vessel by rotation; and

[0188] The cover is configured to expand radially in the blood vessel and is disposed between the impeller and an inner wall of the blood vessel to separate the inner wall of the blood vessel from the impeller.

[0189] For some applications, the plurality of struts of the shield are configured to define a plurality of cells, and wherein the shield is configured to separate the vessel wall from the impeller even if the vessel wall protrudes through a cell of the shield.

[0190] For some applications:

[0191] The impeller is connected to the cover so that a longitudinal axis of the impeller is aligned with a longitudinal axis of the cover; and

[0192] The housing defines a central portion thereof having a generally cylindrical shape, an outer surface of the housing at the generally cylindrical portion of the housing being parallel to the longitudinal axis of the housing.

[0193] For some applications, the impeller is biocompatible and configured to be placed within a blood vessel and to pump blood through the blood vessel by rotation, and wherein the cover is configured to be disposed between the impeller and an inner wall of the blood vessel to separate the blood vessel wall from the impeller.

[0194] For some applications, the cover is configured to expand radially within the blood vessel so that the outer surface of the cover at the generally cylindrical portion of the cover engages the inner wall of the blood vessel, the cover thereby becoming oriented inwardly of the blood vessel so that the longitudinal axis of the cover is parallel to a local longitudinal axis of the blood vessel.

[0195] According to some applications of the present invention, there is further provided a method comprising:

[0196] Placing within a blood vessel of a subject:

[0197] an impeller configured to pump blood through the blood vessel by rotation when in a radially expanded configuration; and

[0198] a radially expandable shroud disposed about the impeller, the shroud defining a plurality of struts, the placing step being performed when the shroud and the impeller are in their axially elongated configurations, and when the shroud is in its axially elongated configuration, the impeller is received within the shroud while the impeller is in its axially elongated configuration;

[0199] radially expanding the cage and the impeller within the blood vessel such that the cage and the impeller are in their radially expanded configurations and the impeller is separated from an inner wall of the blood vessel by the cage; and

[0200] operating a control unit to pump blood through the blood vessel by rotating the impeller,

[0201] The cover includes a plurality of struts, at least some of the struts including: portions thereof that undulate at least when the cover is in the radially expanded configuration of the cover,

[0202] The step of radially expanding the cover includes radially expanding the cover so that a degree of undulation of the undulating portions of the struts becomes greater than a degree of undulation of the undulating portions of the struts when the cover is in its axially elongated configuration.

[0203] For some applications, the blood vessel includes: a renal vein, and wherein operating the control unit to pump blood through the blood vessel includes operating the control unit to pump blood away from a kidney of the subject and toward a vena cava of the subject.

[0204] For some applications, the method further comprises: operating the control unit to:

[0205] measuring pressure within a blood vessel of the subject at a first location within the blood vessel upstream of the impeller and at a second location within the blood vessel downstream of the impeller; and

[0206] The rotation of the impeller is controlled in response to the pressure measured at the first location and the second location.

[0207] For some applications:

[0208] In the absence of the cover, the blood vessel has a predetermined diameter;

[0209] The step of radially expanding the cage includes: widening a portion of the blood vessel such that a diameter of the portion of the blood vessel is greater than the predetermined diameter; and

[0210] The step of radially expanding the impeller includes radially expanding the impeller so that a span width of the impeller is at least the same as the predetermined diameter.

[0211] For some applications, the step of radially expanding the cage includes radially expanding the cage so that for each of the plurality of struts including the plurality of undulating portions:

[0212] a shortest distance from a first longitudinal end of the strut to a second longitudinal end of the strut when the cover is in its axially elongated configuration;

[0213] a shortest distance from a first longitudinal end of the strut to a second longitudinal end of the strut when the cover is in its radially expanded configuration;

[0214] The ratio between the two is greater than 1.05:1.

[0215] For some applications, the step of radially expanding the cover includes radially expanding the cover such that for each of the plurality of struts including the plurality of undulations, the ratio is less than 1.4:1. For some applications, the step of radially expanding the cover includes radially expanding the cover such that for each of the plurality of struts including the plurality of undulations, the ratio is greater than 1.15:1. For some applications, the step of radially expanding the cover includes radially expanding the cover such that for each of the plurality of struts including the plurality of undulations, the ratio is greater than 1.2:1.

[0216] For some applications, the method further comprises: operating the control unit to:

[0217] measuring flow through the blood vessel; and

[0218] The rotation of the impeller is controlled in response to the measured flow.

[0219] For some applications, the step of operating the control unit to measure flow through the blood vessel includes: operating the control unit to measure blood flow through a thermal flow sensor disposed in a housing, the housing being configured such that a direction of blood flow through the housing is substantially parallel to a local longitudinal axis of the blood vessel.

[0220] According to some applications of the present invention, there is also provided a method comprising:

[0221] placing a radially expandable structure within a blood vessel of a subject, wherein the blood vessel has a predetermined diameter in the absence of the radially expandable structure;

[0222] widening the portion of the blood vessel by expanding the radially expandable structure within the portion of the blood vessel such that a diameter of the portion of the blood vessel is greater than the predetermined diameter;

[0223] placing an impeller within the portion of the blood vessel, the impeller comprising a plurality of impeller blades having a span width at least equal to the predetermined diameter; and

[0224] A control unit is operated to pump blood through the blood vessel by rotating the impeller relative to the blood vessel.

[0225] For some applications, the step of expanding the radially expandable structure includes expanding a radially expandable cage disposed around the impeller to separate the impeller from an inner wall of the blood vessel via the cage.

[0226] For some applications, the blood vessel includes: a renal vein, and wherein the step of operating the control unit to pump blood through the blood vessel includes: operating the control unit to pump blood away from a kidney of the subject and toward a vena cava of the subject.

[0227] For some applications, the method further includes: operating the control unit to:

[0228] measuring pressure within a blood vessel of the subject at a first location within the blood vessel upstream of the impeller and at a second location within the blood vessel downstream of the impeller; and

[0229] The rotation of the impeller is controlled in response to the pressure measured at the first location and the second location.

[0230] For some applications, the method further comprises: operating the control unit to:

[0231] measuring flow through the blood vessel; and

[0232] The rotation of the impeller is controlled in response to the measured flow.

[0233] For some applications, the step of operating the control unit to measure flow through the blood vessel includes: operating the control unit to measure blood flow via a thermal flow sensor disposed within a housing, the housing being configured such that a direction of blood flow through the housing is substantially parallel to the local longitudinal axis of the blood vessel.

[0234] For some applications, the step of widening the portion of the vessel comprises widening the portion of the vessel by expanding the radially expandable structure within the portion of the vessel such that the diameter of the portion of the vessel is greater than 105% of the predetermined diameter. For some applications, the step of widening the portion of the vessel comprises widening the portion of the vessel by expanding the radially expandable structure within the portion of the vessel such that the diameter of the portion of the vessel is greater than 115% of the predetermined diameter. For some applications, the step of widening the portion of the vessel comprises widening the portion of the vessel by expanding the radially expandable structure within the portion of the vessel such that the diameter of the portion of the vessel is greater than 125% of the predetermined diameter.

[0235] According to some embodiments of the present invention, there is further provided an apparatus comprising:

[0236] A blood pump configured to pump blood through a blood vessel of a subject, the blood pump comprising:

[0237] an elongated member; and

[0238] an impeller disposed at a distal end of the elongated member and configured to pump blood through the blood vessel by rotation;

[0239] a thermal flow sensor configured to measure the flow of the drawn blood, the thermal flow sensor comprising an upstream temperature sensor, a heating element and a downstream temperature sensor, sequentially disposed along a portion of a length of the elongated element,

[0240] The elongated element includes a housing configured to house the thermal flow sensor and configured such that a direction of blood flow through the housing is substantially parallel to a local longitudinal axis of the blood vessel.

[0241] For some applications, the housing includes: a portion of an outer surface of the elongated member configured to define a groove therein, wherein the upstream temperature sensor, the heating element, and the downstream temperature sensor are sequentially disposed along the groove.

[0242] For some applications, a ratio of a length of the groove to a width of the groove is greater than 4:1.

[0243] For some applications, the device further includes: a cover connected to the elongated member and configured to cover the thermal sensor.

[0244] For some applications, the housing includes: a housing disposed on an outer surface of the elongated element, wherein the upstream temperature sensor, the heating element, and the downstream sensor are sequentially disposed along an interior of the housing.

[0245] For some applications, the housing includes a compressible tube disposed on the outer surface of the elongated member.

[0246] For some applications, a ratio of a length of the housing to a width of the housing is greater than 4:1. For some applications, a ratio of a length of the housing to a height of the housing is greater than 4:1.

[0247] According to some applications of the present invention, there is further provided a method comprising:

[0248] A blood pump is placed into a blood vessel of a subject, the blood pump comprising:

[0249] an elongated member; and

[0250] an impeller disposed at a distal end of the elongated member;

[0251] operating a control unit to measure the flow of the drawn blood using a heating element and a thermal flow sensor, wherein the thermal flow sensor comprises an upstream temperature sensor, a heating element, and a downstream temperature sensor sequentially disposed along a portion of a length of the elongated member;

[0252] The elongated element comprises a housing configured to house the thermal flow sensor and configured such that a direction of blood flow through the housing is substantially parallel to a local longitudinal axis of the blood vessel; and

[0253] The control unit is operated to pump blood through the blood vessel by rotating the impeller at least in part responsive to the measured flow.

[0254] According to some applications of the present invention, there is also provided a device comprising:

[0255] A pump configured to pump a fluid, the pump comprising:

[0256] an elongated member; and

[0257] an impeller disposed at a distal end of the elongated element and configured to draw the fluid by rotation;

[0258] a thermal flow sensor configured to measure the flow rate of the drawn fluid, the thermal flow sensor comprising an upstream temperature sensor, a heating element and a downstream temperature sensor sequentially disposed along a portion of a length of the elongated element,

[0259] The elongated element includes a housing configured to house the thermal flow sensor and configured such that a direction of flow of the fluid through the housing is substantially parallel to a local longitudinal axis of the elongated element.

[0260] For some applications, the housing includes a portion of an outer surface of the elongated member configured to define a groove therein, wherein the upstream temperature sensor, the heating element, and the downstream sensor are sequentially disposed along the groove.

[0261] For some applications, a ratio of a length of the groove to a width of the groove is greater than 4:1.

[0262] For some applications, the device further includes: a cover connected to the elongated member and configured to cover the thermal sensor.

[0263] For some applications, the housing includes: a housing disposed on an outer surface of the elongated element, wherein the upstream temperature sensor, the heating element, and the downstream temperature sensor are sequentially disposed along an interior of the housing.

[0264] For some applications, the housing includes: a compressible tube disposed on the outer surface of the elongated member.

[0265] For some applications, a ratio of a length of the housing to a width of the housing is greater than 4:1. For some applications, a ratio of a length of the housing to a height of the housing is greater than 4:1.

[0266] According to some applications of the present invention, there is also provided a method for use with a plurality of tributary veins providing a main vein, comprising:

[0267] Mechanically separate the blood in multiple veins into a compartment separate from the blood flow in the main vein; and

[0268] Blood flow from the plurality of veins to the main vein is controlled by pumping blood from the compartments into the main vein.

[0269] For some applications, the method further comprises: performing ultrafiltration on the drawn blood.

[0270] For some applications,

[0271] The step of separating the plurality of veins comprises:

[0272] placing a blood-proof sleeve and a spiral support member surrounding the sleeve into the main vein, and

[0273] Using the helical support to connect the sleeve to a wall of the main vein; and

[0274] Pumping blood from the compartment into the main vein includes using the spiral support to guide a distal portion of a blood pump into the compartment and pumping the blood using the blood pump.

[0275] For some applications:

[0276] The step of separating the plurality of veins comprises:

[0277] placing a blood-impermeable sleeve and a spiral portion of a blood pump disposed around the sleeve into the main vein, and

[0278] connecting the sleeve to a wall of the main vein: and

[0279] Pumping blood from the compartment into the main vein includes pumping blood into a plurality of access holes of the blood pump defined by the spiral portion of the blood pump.

[0280] For some applications:

[0281] The step of separating blood in the plurality of veins into a compartment separate from blood flow in the main vein comprises: separating blood in the plurality of renal veins of the subject into a compartment separate from blood flow in a vena cava of the subject by placing a blood impermeable sleeve into the vena cava of the subject so that a downstream end of the sleeve is connected to a wall of the vena cava at a first location downstream of all the renal veins of the subject and so that an upstream end of the sleeve is connected to the wall of the vena cava at a second location upstream of all the renal veins of the subject; and

[0282] The step of pumping blood from the compartment into the main vein includes operating a pump to pump blood from the compartment to a location within an interior portion in fluid communication with the sleeve.

[0283] For some applications, drawing blood from the compartment includes drawing blood in a downstream direction through the plurality of renal veins.

[0284] For some applications, placing the sleeve in the vena cava includes placing the sleeve in the vena cava for less than one week, and operating the pump includes operating the pump for less than one week.

[0285] For some applications, the method further includes identifying the subject as a subject suffering from a condition selected from the group consisting of cardiac insufficiency, congestive heart failure, reduced renal blood flow, increased renal vascular resistance, hypertension and renal insufficiency, and the step of operating the pump includes reducing the blood pressure within multiple renal veins of the subject by operating the pump in response to identifying the subject as suffering from the condition.

[0286] For some applications, placing the sleeve within the subject's vena cava includes anchoring the sleeve to the vena cava by causing the vena cava to compress at least a portion of the sleeve by operating the pump.

[0287] For some applications, operating the pump to pump blood from the compartment to the location within an interior portion in fluid communication with the sleeve includes operating the pump to pump blood from the compartment to a location in the vena cava upstream of the sleeve.

[0288] For some applications, operating the pump to pump blood from the compartment to the location within an interior portion in fluid communication with the sleeve includes operating the pump to pump blood from the compartment to a location in the vena cava downstream of the sleeve.

[0289] For some applications, placing the sleeve into the vena cava comprises placing into the vena cava:

[0290] a support configured to define widened upstream and downstream ends thereof, widened relative to a central portion of said support, and

[0291] an anti-blood seepage sleeve connected to the stent, the sleeve defining its trumpet-shaped upstream and downstream ends, connected to the widened upstream and downstream ends of the stent, respectively; and

[0292] Connecting the stent to the blood vessel so that:

[0293] In response to the blood pressure on a first side of at least one of the plurality of flared ends of the sleeve being greater than on a second side of the at least one flared end of the sleeve, blood flows between an outer side of the at least one flared end of the sleeve and an inner wall of the blood vessel, and

[0294] In response to the blood pressure on the first side of the at least one flared end of the sleeve being smaller than that on the second side of the at least one flared end of the sleeve, the at least one flared end of the sleeve blocks the blood flow between the outer side of the at least one flared end of the sleeve and the inner wall of the blood vessel by contacting the inner wall of the blood vessel.

[0295] For some applications, placing the sleeve into the vena cava comprises placing into the vena cava:

[0296] a sleeve configured to define a plurality of flared ends thereof and a narrow central portion located between the plurality of flared ends; and

[0297] A bracket, configured to define:

[0298] a sleeve-support bracket configured to define a plurality of widened ends thereof and a narrow central portion between the plurality of widened ends that is narrower than the plurality of widened ends of the bracket, the sleeve connecting the sleeve-support bracket of the bracket; and

[0299] A vessel-wall-supporting stent is connected to the narrow central portion of the sleeve-supporting stent and protrudes radially from the sleeve-supporting stent.

[0300] For some applications, drawing blood from the compartment includes drawing blood from a location between an outside of the sleeve and an inner wall of the vena cava.

[0301] For some applications, the method further includes inserting the pump into the compartment through an opening in the sleeve, wherein the pump is insertable.

[0302] For some applications, inserting the pump through the opening includes inserting the pump through an opening having a diameter between 2 mm and 10 mm.

[0303] For some applications, inserting the pump through the opening includes inserting the pump through the opening such that the opening forms a seal around the pump.

[0304] For some applications, the method further includes inserting the pump into the compartment through a pump-receiving sleeve protruding from the sleeve.

[0305] For some applications, inserting the pump into the compartment through the pump-receiving sleeve includes inserting the pump into the compartment through a pump-receiving sleeve having a diameter between 2 mm and 10 mm.

[0306] For some applications, inserting the pump into the compartment through the pump-receiving sleeve includes inserting the pump into the compartment through the pump-receiving sleeve such that the pump-receiving sleeve forms a seal around the pump.

[0307] According to some applications of the present invention, there is also provided a device comprising:

[0308] A blood-proof sleeve;

[0309] at least one support structure configured to connect a first end and a second end of the sleeve to a blood vessel of a subject; and

[0310] A pump is configured to draw blood from an exterior of the sleeve to a location in fluid communication with an interior of the sleeve.

[0311] For some applications, the pump is configured to ultrafilter the blood.

[0312] For some applications, the pump is configured to anchor the structure to the blood vessel by causing the blood vessel to compress at least a portion of the structure around the blood vessel.

[0313] For some applications,

[0314] The structure includes a support configured to define a plurality of widened ends thereof, which widen relative to a central portion of the support, and

[0315] The sleeve comprises a sleeve connected to the bracket,

[0316] The sleeve defines a plurality of flared ends connected to the plurality of widened ends of the bracket, and at least one of the plurality of flared ends of the sleeve is configured to act as a valve by at least partially separating from the widened end of the bracket to which it is connected in response to pressure applied to the flared end of the sleeve.

[0317] For some applications:

[0318] The support structure includes a spiral support member disposed around the sleeve, and

[0319] A distal portion of the blood pump is configured to be guided to surround the exterior of the sleeve using the helical support.

[0320] For some applications:

[0321] The support structure includes a spiral portion of the blood pump disposed around the sleeve and configured to support the sleeve, and

[0322] The pump is configured to draw blood from the exterior of the sleeve by drawing blood into the plurality of access holes of the pump defined by the helical portion of the blood pump.

[0323] For some applications:

[0324] The sleeve is configured to define a plurality of flared ends and a narrow central portion between the plurality of flared ends;

[0325] The structure comprises a support configured to define:

[0326] a sleeve-support bracket configured to define a plurality of widened ends thereof, and a narrow central portion located between the plurality of widened ends that is narrower than the plurality of widened ends of the bracket, the sleeve connecting the sleeve-support bracket of the bracket; and

[0327] A vessel-wall-supporting stent is connected to the narrow central portion of the sleeve-supporting stent and protrudes radially from the sleeve-supporting stent.

[0328] For some applications, the pump is configured to draw blood from between the exterior of the sleeve and an inner wall of the blood vessel by being placed between an exterior of the sleeve and the blood vessel-wall-supporting stent.

[0329] For some applications, the structure is configured to separate blood within a renal vein of the subject into a compartment separate from blood flow within a vena cava of the subject by connecting a downstream end of the sleeve to a wall of the vena cava at a first location downstream of all of the subject's renal veins, and by connecting an upstream end of the sleeve to a wall of the vena cava at a second location upstream of all of the subject's renal veins.

[0330] For some applications, the sleeve is configured to be connected to the vena cava for less than one week, and the pump is configured to operate for less than one week.

[0331] For some applications, the pump is configured to reduce blood pressure within renal veins of the subject by pumping blood.

[0332] For some applications, the pump is configured to pump blood from the compartment to a location within the vena cava.

[0333] For some applications, the pump is configured to pump blood from the compartment to a location within the vena cava upstream of the sleeve.

[0334] For some applications, the pump is configured to pump blood from the compartment to a location within the vena cava downstream of the sleeve.

[0335] For some applications, the sleeve is configured to define an opening through which the pump can be inserted.

[0336] For some applications, the opening has a diameter between 2 mm and 10 mm.

[0337] For some applications, the opening is sized to form a seal around the pump.

[0338] For some applications, the device further includes a pump-containing sleeve protruding from the anti-blood seepage sleeve, the pump-containing sleeve being configured to accommodate insertion of the pump through the exterior of the anti-blood seepage sleeve.

[0339] For some applications, the pump-receiving sleeve has an inner diameter between 2 mm and 10 mm.

[0340] For some applications, the pump-receiving sleeve is sized to form a seal around the pump.

[0341] According to some applications of the present invention, there is further provided a method comprising:

[0342] placing a stent in a blood vessel at a placement location of the stent; and

[0343] The stent is at least partially anchored to the blood vessel at the placement site by applying a suction force within the blood vessel to compress at least a portion of the stent around the blood vessel.

[0344] For some applications, the blood vessel includes a blood vessel having a predetermined diameter at the placement location, and the step of placing the stent in the blood vessel includes placing the stent in the blood vessel having a diameter smaller than the predetermined diameter.

[0345] For some applications, the step of surrounding the vessel to compress at least a portion of the stent includes oversizing the stent to reduce anchoring of the stent to the vessel to a degree relative to if at least the portion of the stent was not anchored around the vessel.

[0346] According to some applications of the present invention, there is also a device comprising:

[0347] a stent configured to be placed in a blood vessel at a placement location of the stent;

[0348] A pump is configured to anchor the stent to the blood vessel at the placement site by applying a suction force within the blood vessel to compress at least a portion of the stent around the blood vessel.

[0349] For some applications, the blood vessel comprises a blood vessel having a predetermined diameter at the placement location, and the stent comprises a stent having a diameter less than the predetermined diameter.

[0350] According to some applications of the present invention, there is further provided an apparatus comprising:

[0351] A stent configured for placement in a blood vessel, the stent being configured to define a plurality of widened ends thereof that are widened relative to a central portion of the stent; and

[0352] a blood-proof sleeve connected to the stent,

[0353] The sleeve defines a plurality of flared ends connected to the plurality of widened ends of the bracket, and at least one of the plurality of flared ends of the sleeve is configured to act as a valve by at least partially separating from the widened end of the bracket to which it is connected in response to pressure applied to the flared end of the sleeve.

[0354] According to some applications of the present invention, there is also provided a method comprising:

[0355] Placing within a blood vessel of a subject:

[0356] a support configured to define widened upstream and downstream ends thereof, widened relative to a central portion of said support, and

[0357] a blood-proof sleeve connected to the stent, the sleeve defining flared upstream and downstream ends thereof connected to the widened upstream and downstream ends of the stent, respectively; and

[0358] Connecting the stent to the blood vessel so that:

[0359] In response to the blood pressure on a first side of at least one of the plurality of flared ends of the sleeve being greater than on a second side of the at least one flared end of the sleeve, blood flows between an outer side of the at least one flared end of the sleeve and an inner wall of the blood vessel, and

[0360] In response to the blood pressure on the first side of the at least one flared end of the sleeve being smaller than that on the second side of the at least one flared end of the sleeve, the at least one flared end of the sleeve blocks the blood flow between the outer side of the at least one flared end of the sleeve and the inner wall of the blood vessel by contacting the inner wall of the blood vessel.

[0361] According to some applications of the present invention, there is further provided an apparatus comprising:

[0362] a blood-proof sleeve defining a plurality of flared ends and a narrow central portion between the flared ends; and

[0363] A stent configured for placement within a blood vessel, the stent being configured to define:

[0364] a sleeve-support bracket configured to define a plurality of widened ends thereof and a narrow central portion located between the plurality of widened ends that is narrower than the plurality of widened ends of the bracket, the sleeve connecting the sleeve-support bracket of the bracket; and

[0365] A vessel-wall-supporting stent is connected to the narrow central portion of the sleeve-supporting stent and protrudes radially from the sleeve-supporting stent.

[0366] For some applications, the device further includes a blood pump configured to draw blood from between the exterior of the sleeve and an inner wall of the blood vessel by being placed between an exterior of the sleeve and the blood vessel-wall-supporting stent.

[0367] For some applications, a diameter of the narrow central portion of the sleeve is between 8 mm and 35 mm.

[0368] For some applications, a maximum diameter of the flared ends of the sleeve is between 10 mm and 45 mm.

[0369] For some applications, a ratio of a maximum diameter of the flared ends of the sleeve to a diameter of the narrow central portion of the sleeve is between 1.1:1 and 2:1.

[0370] For some applications, a maximum diameter of the vessel-wall-supporting stent is between 10 mm and 50 mm.

[0371] For some applications, a ratio of a maximum diameter of the wall-support stent to a diameter of the narrow central portion of the sleeve-support stent is between 1.1:1 and 5:1. For some applications, the ratio is greater than 1.5:1.

[0372] For some applications, a length of the sleeve is greater than 6 mm. For some applications, the length of the sleeve is less than 80 mm. For some applications, a length of each of the plurality of flared ends of the sleeve is greater than 3 mm. For some applications, the length of each of the plurality of flared ends of the sleeve is less than 40 mm. For some applications, a length of the narrow central portion of the sleeve is greater than 3 mm. For some applications, the length of the narrow central portion of the sleeve is less than 70 mm.

[0373] According to some applications of the present invention, there is further provided a method comprising:

[0374] Placing within a blood vessel of a subject:

[0375] a blood-proof sleeve defining a plurality of flared ends and a narrow central portion between the flared ends; and

[0376] A bracket, configured to define:

[0377] a sleeve-support bracket configured to define a plurality of widened ends thereof and a narrow central portion between the plurality of widened ends that is narrower than the plurality of widened ends of the bracket, the sleeve connecting the sleeve-support bracket of the bracket; and

[0378] a vessel-wall-supporting stent connected to the narrow central portion of the sleeve-supporting stent and projecting radially from the sleeve-supporting stent; and

[0379] The stent is connected to the blood vessel by supporting the wall of the blood vessel so that the vessel-wall-supporting stent of the stent holds the blood vessel open, and the sleeve-supporting stent supports the sleeve within the blood vessel.

[0380] For some applications, the method further includes pumping blood from a location between an outer side of the sleeve and an inner wall of the vena cava by placing a pump between the outer portion of the sleeve and the vessel-wall-supporting stent.

[0381] For some applications, placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, wherein a diameter of the narrow central portion of the sleeve is between 8 mm and 35 mm.

[0382] For some applications, placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, wherein a maximum diameter of the flared ends of the sleeve is between 10 mm and 45 mm.

[0383] For some applications, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, wherein a maximum diameter of the plurality of flared ends of the sleeve and a diameter of the narrow central portion of the sleeve are between 1.1:1 and 2:1.

[0384] For some applications, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, and a maximum diameter of the blood vessel-wall-supporting stent is between 10 mm and 50 mm.

[0385] For some applications, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel with a maximum diameter of the wall-supporting stent and a diameter of the narrow central portion of the sleeve-supporting stent being between 1.1:1 and 5:1. For some applications, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel with the ratio being greater than 1.5:1.

[0386] For some applications, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, wherein a length of the sleeve is greater than 6 mm. For some applications, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, wherein the length of the sleeve is less than 80 mm. For some applications, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, wherein each of the plurality of flared ends of the sleeve has a length greater than 3 mm. For some applications, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, wherein each of the plurality of flared ends of the sleeve has a length less than 40 mm. For some applications, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, wherein a length of the narrow central portion of the sleeve is greater than 3 mm. For some applications, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, wherein the length of the narrow central portion of the sleeve is less than 70 mm.

[0387] According to some applications of the present invention, there is also provided a method for operating a blood pump disposed in a blood vessel of a subject, the method comprising:

[0388] placing an occlusive member within the blood vessel, the occlusive member having an occlusive state in which the occlusive member occludes the blood vessel, and a non-occlusive state in which the occlusive member does not occlude the blood vessel;

[0389] drawing blood in a downstream direction from a location on an upstream side of fluid communication with the occlusion member;

[0390] drawing blood into a location of the subject's blood vessel on a downstream side of fluid communication with the occlusion member,

[0391] The pumping of the blood into the subject's blood vessel is performed in a manner to maintain the occluding member in an occlusive state thereof, in which the occluding member occludes the blood vessel.

[0392] For some applications, the method further includes ultrafiltering the blood prior to pumping the blood into the location in the subject's blood vessel.

[0393] For some applications, the step of placing the occlusive member in the blood vessel includes placing the occlusive member in the blood vessel for less than one week, and the step of pumping the blood includes pumping the blood into the blood vessel for less than one week. For some applications, the step of placing the occlusive member in the blood vessel includes placing the occlusive member in the blood vessel for more than one week, and the step of pumping the blood includes pumping the blood into the blood vessel for less than one week.

[0394] For some applications, the method further includes identifying the subject as a subject suffering from a condition selected from the group consisting of: cardiac insufficiency, congestive heart failure, reduced renal blood flow, increased renal vascular resistance, hypertension and renal insufficiency, the blood vessel includes a renal vein of the subject, and the step of drawing blood in the downstream direction from the position on the upstream side of the fluid connected to the occlusion member includes: in response to identifying the subject as suffering from the condition, reducing the blood pressure within the renal vein of the subject by drawing the blood in the downstream direction.

[0395] For some applications, the step of pumping the blood into the subject's blood vessel to maintain the occlusive member in its occlusive state includes: pumping the blood into the subject's blood vessel so that the hydrodynamic pressure of the blood pumped into the subject's blood vessel maintains the occlusive member in its occlusive state.

[0396] For some applications, the step of placing the occlusion member into the blood vessel includes: placing a valve having a plurality of valve leaflets into the blood vessel, and pumping the blood into the subject's blood vessel so that the hydrodynamic pressure of the blood pumped into the subject's blood vessel maintains the occlusion member in its occluded state. The step of pumping the blood into the subject's blood vessel so that the blood pumped into the subject's blood vessel directly impacts a plurality of downstream sides of the plurality of valve leaflets.

[0397] For some applications, the step of placing the valve in the blood vessel includes placing the valve in the blood vessel such that:

[0398] In response to blood pressure on an upstream side of the valve leaflets exceeding pressure on the downstream side of the valve leaflets, blood flows in an antegrade direction between cusps of the valve leaflets and an inner wall of the blood vessel, and

[0399] In response to the blood pressure on the downstream side of the multiple valve leaflets exceeding the pressure on the upstream side of the multiple valve leaflets, the valve occludes retrograde blood flow by the multiple tips of the multiple valve leaflets contacting the inner wall of the blood vessel.

[0400] For some applications, the step of pumping the blood into the subject's blood vessel so that the blood pumped into the subject's blood vessel directly impacts downstream sides of the valve leaflets includes reducing blood clots at the valve leaflets by flushing the valve leaflets.

[0401] For some applications, the method further includes pumping an anticoagulant agent, along with the blood pumped into the subject's blood vessel, into the subject's blood vessel so that the anticoagulant directly impacts the plurality of valve leaflets.

[0402] For some applications, placing the valve into the blood vessel includes maintaining portions of the valve leaflets in contact with a wall of the blood vessel by inflating a balloon.

[0403] For some applications, placing the valve into the blood vessel includes maintaining portions of the valve leaflets in contact with a wall of the blood vessel by radially outwardly expanding portions of a slit tube.

[0404] For some applications, pumping the blood so that the blood directly impacts downstream sides of the valve leaflets includes pumping the blood into a blood vessel of the subject through holes configured to direct the blood toward the downstream sides of the valve leaflets.

[0405] For some applications, the step of pumping the blood so that the blood directly impacts downstream sides of the valve leaflets includes pumping the blood into the subject's blood vessel through a pump catheter configured to define a radial protrusion that curves concavely from a distal end of the catheter, the radial protrusion being configured to direct the blood pumped into the blood vessel toward the valve leaflets.

[0406] For some applications, pumping the blood so that the blood directly impacts downstream sides of the valve leaflets includes pumping the blood into a blood vessel of the subject through holes disposed adjacent bases of the valve leaflets.

[0407] For some applications, the step of pumping the blood so that the blood directly impacts the downstream sides of the valve leaflets includes pumping the blood into the subject's blood vessel through a plurality of holes disposed adjacent a location along the lengths of the valve leaflets below midway between the tines of the leaflets and the bases of the valve leaflets.

[0408] According to some applications of the present invention, there is also provided a device for use with a blood vessel of a subject, the device comprising:

[0409] an occlusive member configured to be placed within one of the blood vessels, the occlusive member having an occlusive state, wherein the occlusive member occludes the blood vessel, and a non-occlusive state, wherein the occlusive member does not occlude the blood vessel;

[0410] A vascular pump is configured to:

[0411] drawing blood in a downstream direction from a location on an upstream side of fluid communication with the occlusion member, and

[0412] Blood is pumped into a location of the subject's blood vessel on a downstream side of fluid communication with the occlusion member, the pump being configured to cause the pumping of blood into the blood vessel to be effected in a manner to maintain the occlusion member in an occlusive state thereof.

[0413] For some applications, the blood pump is configured to ultrafilter the blood before pumping the blood into a blood vessel of the subject.

[0414] For some applications, the occluder is configured to be placed in the blood vessel for less than one week, and the pump is configured to pump blood into the blood vessel for less than one week. For some applications, the occluder is configured to be placed in the blood vessel for more than one week, and the pump is configured to pump blood into the blood vessel for less than one week.

[0415] For some applications, the pump is configured to maintain the occlusive member in its occlusive state by pumping the blood into the subject's blood vessel, and the pump is configured to maintain the occlusive member in its occlusive state by pumping the blood into the subject's blood vessel, so that the hydrodynamic pressure of the blood pumped into the subject's blood vessel maintains the occlusive member in its occlusive state.

[0416] For some applications, the occlusion member includes a valve having multiple valve leaflets, and the pump is configured to pump the blood into the subject's blood vessel so that the hydrodynamic pressure of the blood maintains the occlusion member in its occluded state, by pumping the blood into the subject's blood vessel so that the blood pumped into the subject's blood vessel directly impacts multiple downstream sides of the multiple valve leaflets.

[0417] For some applications, the valve is configured to:

[0418] In response to blood pressure on an upstream side of the valve leaflets exceeding pressure on the downstream side of the valve leaflets, blood flows in an antegrade direction between cusps of the valve leaflets and an inner wall of the blood vessel, and

[0419] In response to the blood pressure on the downstream side of the multiple valve leaflets exceeding the pressure on the upstream side of the multiple valve leaflets, the valve is closed by the multiple tips of the multiple valve leaflets contacting the inner wall of the blood vessel.

[0420] For some applications, the pump is configured to reduce blood clots at the valve leaflets by flushing the valve leaflets by pumping the blood into the subject's blood vessel so that the blood pumped into the subject's blood vessel directly impacts downstream sides of the valve leaflets.

[0421] For some applications, the device is used in conjunction with an anticoagulant, and the pump is configured to pump the anticoagulant, along with the blood pumped into the subject's blood vessel, into the subject's blood vessel so that the anticoagulant directly impacts the multiple valve leaflets.

[0422] For some applications, the device further includes a balloon configured to maintain portions of the valve leaflets in contact with a wall of the blood vessel by being inflated.

[0423] For some applications, the device further includes a slit configured to be inserted into the blood vessel through portions of the slit between the plurality of radially expanded slits and to maintain portions of the plurality of valve leaflets in contact with a wall of the blood vessel.

[0424] For some applications, the blood pump is configured to be connected to the valve, the blood pump includes a plurality of output holes for pumping the blood into a blood vessel of the subject, and the plurality of output holes are configured so that when the blood pump is connected to the valve, the plurality of output holes direct the blood toward the plurality of downstream sides of the plurality of valve leaflets.

[0425] For some applications, the blood pump is configured to be connected to the valve, the blood pump comprising a blood pump catheter defining a radial protrusion that is concavely curved from a distal end of the catheter, the radial protrusion being configured to guide blood drawn into the blood vessel toward the plurality of valve leaflets when the blood pump is connected to the valve.

[0426] For some applications, the blood pump is configured to connect to the valve, the blood pump includes a plurality of output holes for pumping the blood into a blood vessel of the subject, and the plurality of output holes are arranged on the blood pump so that when the blood pump is connected to the valve, the plurality of holes are adjacent to the plurality of bases of the plurality of valve leaflets.

[0427] For some applications, the output holes are positioned on the blood pump so that when the blood pump is connected to the valve, the output holes are adjacent to a position along the lengths of the valve leaflets below midway between the tines of the leaflets and the bases of the valve leaflets.

[0428] According to some applications of the present invention, there is also provided a device for use with a blood vessel of a subject, the device comprising:

[0429] a blood pump configured to draw blood in a downstream direction through the blood vessel into the pump; and

[0430] A valve includes multiple rigid portions thereof, the multiple rigid portions being configured to connect the valve to the blood vessel, the valve being configured to connect to a distal portion of the blood pump and to prevent blood from flowing through the valve in a retrograde direction.

[0431] For some applications, the valve further includes a plurality of resilient valve leaflets coupled to the plurality of rigid portions of the valve.

[0432] According to some applications of the present invention, there is further provided a method comprising:

[0433] providing an artificial valve defining a plurality of valve leaflets; and

[0434] The valve is placed in a blood vessel to:

[0435] In response to blood pressure on an upstream side of the valve leaflets exceeding pressure on the downstream side of the valve leaflets, blood flows in an antegrade direction between cusps of the valve leaflets and an inner wall of the blood vessel, and

[0436] In response to the blood pressure on the downstream side of the multiple valve leaflets exceeding the pressure on the upstream side of the multiple valve leaflets, the valve is closed by the multiple tips of the multiple valve leaflets contacting the inner wall of the blood vessel.

[0437] According to some applications of the present invention, there is also provided a device comprising:

[0438] An artificial valve comprises a plurality of elastic valve leaflets and a rigid valve support, wherein the plurality of valve leaflets are connected to the valve support so that:

[0439] In response to pressure on a first side of the plurality of valve leaflets exceeding pressure on a second side of the plurality of valve leaflets, the plurality of leaflets open by separating the plurality of tines of the plurality of valve leaflets from the rigid support, and

[0440] In response to the blood pressure on the second side of the plurality of valve leaflets exceeding the pressure on the first side of the plurality of valve leaflets, the valve closes by the plurality of tines of the plurality of leaflets contacting the rigid support.

[0441] According to some applications of the present invention, there is further provided a device comprising:

[0442] A blood pump, comprising:

[0443] One tube;

[0444] The first and second one-way valves are respectively disposed at the proximal and distal ends of the tube;

[0445] a membrane connected to the interior of the tube to separate the tube into a first compartment in fluid communication with the plurality of valves and a second compartment not in fluid communication with the plurality of valves; and

[0446] A pumping mechanism is configured to pump fluid through the tube by increasing and gradually decreasing the size of the first compartment by moving the membrane relative to the tube.

[0447] For some applications, the tube includes a support, and a material disposed on the support.

[0448] For some applications, the occlusive member is configured to be placed in the blood vessel for less than one week.

[0449] For some applications, one of the plurality of valves is configured to prevent backflow of blood from the tube into the blood vessel, and a second of the plurality of valves is configured to prevent backflow of blood from the blood vessel into the tube.

[0450] For some applications, the blood pump is configured to be placed in a renal vein of a subject and to pump blood in a downstream direction from the renal vein to a vena cava of the subject.

[0451] For some applications, the blood pump is configured to occlude backflow of blood from the vena cava to the renal vein.

[0452] According to some applications of the present invention, there is further provided a method comprising:

[0453] connecting a tube to an inner wall of a blood vessel of a subject,

[0454] The first and second directional valves are disposed at the proximal and distal ends of the tube, respectively, and

[0455] a membrane connected to the interior of the tube to separate the tube into a first compartment in fluid communication with the plurality of valves and a second compartment not in fluid communication with the plurality of valves; and

[0456] A pumping mechanism is operated to draw fluid through the tube by increasing and gradually decreasing the size of the first compartment by moving the membrane relative to the tube.

[0457] For some applications, the tube includes a stent and a material disposed on the stent, and the step of connecting the tube to the inner wall of the blood vessel includes connecting the stent and the material to the inner wall of the blood vessel.

[0458] For some applications, connecting the tube to the inner wall of the blood vessel includes connecting the tube to the inner wall of the blood vessel for less than one week.

[0459] For some applications, operating the pumping mechanism includes operating the pumping mechanism so that one of the plurality of valves prevents backflow of blood from the tube into the blood vessel and a second of the plurality of valves prevents backflow of blood from the blood vessel into the tube.

[0460] For some applications, the step of connecting the tube to the inner wall of the blood vessel includes connecting the tube to an inner wall of a renal vein of a subject, and the step of operating the pumping mechanism includes pumping blood in a downstream direction from the renal vein to a vena cava of the subject.

[0461] For some applications, connecting the tube to the inner wall of the blood vessel includes occluding backflow of blood from the vena cava to the renal vein.

[0462] For some applications, the method further includes identifying the subject as a subject suffering from a condition selected from the group consisting of: cardiac insufficiency, congestive heart failure, reduced renal blood flow, increased renal vascular resistance, hypertension and renal insufficiency, and the step of operating the pump includes: in response to identifying the subject as suffering from the condition, operating the pump to pump blood in the downstream direction from the renal vein to the vena cava to reduce the blood pressure within the renal vein of the subject.

[0463] According to some applications of the present invention, there is also provided a method comprising:

[0464] operating a pump to draw blood in a downstream direction through a first vein that is a branch of a second vein and forms a confluence with the second vein; and

[0465] A small hole at the confluence is covered with a small hole-covering umbrella disposed in the second vein to avoid backflow of blood from the second vein to the first vein.

[0466] For some applications, operating the blood pump includes ultrafiltration of the pumped blood.

[0467] For some applications, the aperture-covering umbrella includes: when in an open configuration, a aperture-covering umbrella has a diameter greater than 6 mm, and the step of covering the aperture with the umbrella includes covering the aperture with the umbrella having a diameter greater than 6 mm.

[0468] For some applications, operating the blood pump includes causing the ostium-covering umbrella to form a seal relative to a wall of the second vein surrounding the ostium.

[0469] For some applications, the first vein comprises a renal vein of the subject, and the second vein comprises a vena cava of the subject, and pumping blood in the downstream direction comprises pumping blood from the renal vein in a downstream direction toward the vena cava.

[0470] For some applications, preventing backflow of blood from the second vein to the first vein includes preventing backflow of blood from the vena cava to the renal vein.

[0471] For some applications, the method further includes identifying the subject as a subject suffering from a condition selected from the group consisting of cardiac insufficiency, congestive heart failure, reduced renal blood flow, increased renal vascular resistance, hypertension and renal insufficiency, and the step of operating the pump includes, in response to identifying the subject as suffering from the condition, operating the pump to pump blood in the downstream direction from the renal vein to the vena cava to reduce the blood pressure within the renal vein of the subject.

[0472] According to some applications of the present invention, there is also provided a device for use with a first vein of a subject, wherein the first vein is a branch of a second vein and merges with a second vein, the device comprising:

[0473] a catheter configured to be placed in the first vein, a distal end of the catheter configured to draw blood in a downstream direction through the first vein and into the catheter; and

[0474] A pore-covering umbrella is provided around the outside of the catheter and is configured to be placed on the second vein at the confluence, and the pore-covering umbrella covers a pore at the confluence from a position within the second vein so that the umbrella prevents backflow of blood from the second vein to the first vein.

[0475] For some applications, the catheter is configured to cause the ostium-covering umbrella to become sealed relative to a wall of the second vein surrounding the ostium by pumping the blood.

[0476] For some applications, the aperture-covering umbrella has a diameter greater than 6 mm when in an open configuration.

[0477] For some applications, the first vein comprises a renal vein of the subject, and the second vein comprises a vena cava of the subject, and the catheter is configured to draw blood by drawing blood in a downstream direction from the renal vein.

[0478] For some applications, the ostium at a confluence of the renal vein and the vena cava is covered by the ostium-covering umbrella from a position within the vena cava, the ostium-covering umbrella being configured to prevent blood from flowing back from the vena cava into the renal vein.

[0479] According to some applications of the present invention, there is also provided a device comprising:

[0480] A catheter;

[0481] an extraction mechanism configured to draw fluid into a distal end of the catheter; and

[0482] An orifice-covering umbrella is disposed about the catheter, the umbrella having a diameter of at least 6 mm when in an open configuration thereof.

[0483] For some applications, the diameter of the aperture-covering umbrella is between 10 mm and 20 mm. For some applications, the diameter of the aperture-covering umbrella is between 15 mm and 25 mm.

[0484] According to some applications of the present invention, there is further provided a method for measuring flow in a blood vessel, comprising:

[0485] occluding the blood vessel with an occluding member;

[0486] drawing blood from an upstream side of the occluding member to a downstream side of the occluding member;

[0487] measuring blood pressure on the upstream and downstream sides of the occlusive member;

[0488] modulating the pumping to equalize the pressure on the downstream side of the occlusion member to the pressure on the upstream side of the occlusion member;

[0489] measuring a flow rate of blood through the pump when the pressure on the downstream side of the occlusion member is equal to the pressure on the upstream side of the occlusion member;

[0490] designating the measured flow rate as a baseline flow rate; and

[0491] Subsequently, a flow rate of blood through the pump relative to the baseline flow rate is measured.

[0492] For some applications, the method further includes specifying a baseline measure of vascular resistance of the subject in response to specifying the baseline flow rate, and then measuring the subject's vascular resistance relative to the baseline vascular resistance.

[0493] The present invention will be more fully understood from the following detailed description of its various embodiments in conjunction with the accompanying drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS

[0494] Figure 1A -B is a schematic diagram of a healthy subject's right heart during diastole and systole respectively;

[0495] Figure 1C A set of graphs showing a central venous flow velocity distribution and a central venous pressure distribution of a healthy subject relative to an ECG cycle of the subject;

[0496] Figure 2A - B is a schematic diagram of the right heart of a subject suffering from congestive heart failure during diastole and systole respectively;

[0497] Figure 2C a set of graphs showing the distribution of central venous flow velocity and central venous pressure of the subject suffering from congestive heart failure relative to the subject's ECG cycle;

[0498] Figure 3A is a schematic diagram of blood return toward the plurality of kidneys of the subject suffering from congestive heart failure;

[0499] Figure 3B a set of graphs showing the central venous flow velocity distribution and renal venous pressure distribution of the subject suffering from congestive heart failure relative to the subject's electrocardiogram cycle;

[0500] Figure 4Ais a schematic diagram of a pump and an occlusive member placed in the left and right renal veins of a subject suffering from congestive heart failure according to certain applications of the present invention;

[0501] Figure 4B A set of graphs showing the central venous flow velocity distribution and renal venous pressure distribution of a subject suffering from congestive heart failure after placing a blood pump in the left and right renal veins of the subject and activating the blood pump relative to the subject's electrocardiogram cycle according to some applications of the present invention;

[0502] Figure 5A -D is a schematic diagram of a reversing valve disposed around a blood pump catheter according to certain applications of the present invention;

[0503] Fig. 6A -G is a schematic diagram of the configuration of the blood pump catheter used with the reversing valve according to certain applications of the present invention;

[0504] Fig. 7A -B is a schematic diagram of a blood pump catheter and a non-retrograde valve placed in the renal vein when the non-retrograde valve is in its closed and open states, respectively, according to certain applications of the present invention;

[0505] Fig. 8A -B is a schematic diagram of various fields of view of a blood pump according to certain applications of the present invention;

[0506] Fig.9A -D is according to some applications of the present invention Fig. 8A -B is a schematic diagram of the various stages of an operating cycle of the blood pump;

[0507] Fig. 10A -D is a schematic diagram of a sleeve configured to occlude blood flow from the vena cava of a subject to multiple renal veins of the subject according to certain applications of the present invention;

[0508] Fig. 10E -F is a schematic diagram of connecting a sleeve to a vena cava of a subject using a helical support configured to occlude blood flow from the vena cava of the subject to a plurality of renal veins of the subject in accordance with certain applications of the present invention;

[0509] Figure 10G is a schematic diagram of a sleeve connected to a spiral blood pump catheter according to some applications of the present invention, the sleeve and the blood pump catheter being configured to occlude blood flow from a subject's vena cava to a plurality of renal veins of the subject;

[0510] Fig.11A-C is a schematic diagram of a blood pump catheter placed in a renal vein of a subject according to certain applications of the present invention such that a small hole-covering umbrella surrounding the exterior of the catheter covers the small hole located at the confluence between the vena cava and the renal vein of the subject;

[0511] Figure 12Ai -ii and 12B-E are schematic diagrams of a blood pump including an impeller disposed in a radially expanding cover according to certain applications of the present invention;

[0512] Fig.13A -D is a schematic diagram of stages in a method of manufacturing an impeller for a blood pump according to certain applications of the present invention;

[0513] Fig.14A -B is a schematic diagram of a plurality of sutures tied around a portion of a stent of an impeller according to certain applications of the present invention;

[0514] Fig.15 is a schematic diagram of an impeller for use in a blood pump according to certain applications of the present invention;

[0515] Fig.16A -B is a schematic diagram of a three-blade impeller for use in a blood pump according to certain applications of the present invention;

[0516] Fig.17 A radially expanding shield for use with an impeller-based blood pump according to certain applications of the present invention;

[0517] Figure 18Ai-18Aiii are schematic diagrams of various views and / or multiple configurations of a support for an impeller according to certain applications of the present invention;

[0518] Figure 18Bi-18Biii are various views and / or configurations of a support for an impeller according to certain applications of the present invention, Figure 18Bi-18Biii The impeller support configuration to define the expansion ratio is shown in Figure 18Ai-18Aiii A schematic diagram of a plurality of blades of the impeller support having a larger cross-section;

[0519] Fig. 18C is a schematic diagram of a radially expandable shield including a plurality of struts having a plurality of undulating portions thereof according to certain applications of the present invention;

[0520] Fig.18D is a schematic diagram of multiple side views of multiple radially expanding shields according to certain applications of the present invention;

[0521] Fig.19A-B is a schematic diagram of an impeller shroud configuration according to certain applications of the present invention to define a generally cylindrical central portion in the absence of any forces acting on the shroud;

[0522] Fig. 20 is a schematic diagram of an impeller guard configured to be placed in a blood vessel to expand the diameter of a portion of the blood vessel relative to the diameter of the portion of the blood vessel in the absence of the impeller guard, according to some applications of the present invention;

[0523] Fig.21A is a schematic diagram of a plurality of impeller-based blood pumps according to certain applications of the present invention inserted into the left and right renal veins of a subject through the femoral vein of the subject;

[0524] Fig. 21B is a schematic diagram of inserting impeller-based blood pumps into the left and right renal veins of a subject through the subject's subclavian vein according to certain applications of the present invention;

[0525] Figure 22Ai -ii, 22Bi-ii, and 22Ci-ii are schematic diagrams of a heat flow sensor and a housing for accommodating the heat flow sensor according to certain applications of the present invention; and

[0526] Fig.23 is a graph illustrating the results of experiments performed on a pig using an impeller-based blood pump according to some applications of the present invention. DETAILED DESCRIPTION

[0527] Please refer to Figure 1A -B, which is a schematic diagram of a healthy subject's heart during diastole and systole. Figure 1A As shown, during diastole, blood flows from the subject's right atrium (RA) 20 to the subject's right ventricle (RV) 22. Figure 1B As shown, during systole, the tricuspid valve 24 separating the right ventricle from the right atrium closes as the right atrium pumps blood toward the subject's lungs. During systole, the long-axis contraction of the right ventricle, the right atrium fills with blood from the vena cava 26, and the right atrium expands to pump blood into the right atrium.

[0528] Figure 1CA set of graphs showing the central venous flow velocity distribution and central venous pressure distribution of a healthy subject relative to the subject's electrocardiographic cycle. The flow velocity distribution is characterized by biphasic forward flow, with flow during systole greater than during diastole. Typically, there is a small amount of reverse flow AR during atrial systole. The central venous pressure distribution is characterized by relatively low pressures over the duration of the cardiac cycle, with the A-wave (e.g., the pressure during atrial systole) being generally greater than the V-wave (e.g., the pressure during systole).

[0529] Please refer to Figure 2A -B, which is a schematic diagram of the right heart of a subject suffering from congestive heart failure during diastole and systole respectively. Figure 2A As shown, as in the healthy heart, during diastole, blood flows from the subject's right atrium 20 to the subject's right ventricle 22. Figure 2B As shown, when the high atrial pressure is transmitted to the vena cava, during systole, the congestion of the subject's right atrium is shortened because the pressure in the right atrium is too high, causing it to increase pressure in the vena cava 26. In certain situations (such as situations of excessive right atrial pressure, tricuspid regurgitation, or atrial fibrillation), due to the shortening of the congestion of the subject's right atrium, there may be retrograde flow of blood from the right atrium into the vena cava 26, and / or multiple tributaries of the vena cava.

[0530] Figure 2C A set of graphs showing the central venous flow velocity distribution and the central venous pressure distribution of the subject suffering from congestive heart failure relative to the electrocardiographic cycle of the subject. The flow velocity distribution is characterized by an increase in retrograde flow AR at the end of diastole, and an antegrade flow during systole that is less than that during diastole. For example, in some subjects there is zero flow, or retrograde flow during systole. The central venous pressure distribution is characterized by a relatively high pressure over the duration of the cardiac cycle, with the V wave being higher relative to the V wave of, in particular, a healthy heart, and relative to the A wave of the subject.

[0531] Please refer to Figure 3A , which is a schematic diagram of blood returning through the subject's left and right renal veins 32 toward the multiple kidneys 30 of the subject suffering from congestive heart failure. Figure 3B A set of graphs showing the central venous flow velocity distribution and renal venous pressure distribution of the subject suffering from congestive heart failure relative to the subject's electrocardiogram cycle. Figure 3BThe diagram shown in Figure 2C Same as shown in Figure 3B The pressure distribution shown in FIG. 1 is that of the renal vein, while in Figure 2C The pressure profile depicted in is the central venous pressure profile. As shown, substantially in the absence of a device placed in the renal vein (as practiced in accordance with certain applications of the present invention), and assuming that the renal vein is at the same height as the central venous system, the renal venous pressure profile is identical to the central venous pressure profile. The renal venous pressure profile is characterized by relatively high pressures exceeding the duration of the cardiac cycle, with the V wave being particularly higher relative to a healthy heart.

[0532] Please refer to Figure 4A , which is a schematic diagram of a blood pump 34 and an occlusion member 36 placed in the left and right renal veins 32 of a subject suffering from congestive heart failure according to certain applications of the present invention. To provide acute treatment to a subject suffering from cardiac insufficiency, congestive heart failure, low renal blood flow, high renal vascular resistance, hypertension, and renal insufficiency, the pump and the occlusion member are typically placed in the renal veins of the subject. For example, the pump and the occlusion member may be placed in the renal veins of the subject for a period of more than one hour (e.g., more than one day), less than one week (e.g., less than four days), and / or between one hour and one week (e.g., between one day and four days). For certain applications, to provide chronic treatment to a subject suffering from cardiac insufficiency, congestive heart failure, low renal blood flow, high renal vascular resistance, hypertension, and renal insufficiency, the pump and the occlusion member are chronically placed in the renal veins of the subject. For some applications, a long-term treatment is applied to a subject for more than a few weeks, months, or years, wherein the pump and the occlusion are intermittently placed in multiple renal veins of the subject, and the subject undergoes intermittent treatment according to the techniques described herein. For example, the subject can undergo intermittent treatment at intervals of several days, weeks, or months.

[0533] The occlusion member is configured to occlude the renal vein at an occlusion position. The pump is configured to pump blood in a downstream direction from a location on the upstream side of the occlusion member to a location on the downstream side of the occlusion member. In doing so, the pump reduces pressure within the renal vein. The occlusion member is configured to protect the renal vein from blood backflow from the vena cava into the renal vein.

[0534] Typically, due to the decrease in pressure in the renal vein caused by the pumping of the blood in the downstream direction, perfusion of the kidney increases. In turn, due to the increased blood flow into the renal vein, this may cause the pressure in the multiple renal veins to increase relative to the pressure in the multiple renal veins immediately after the start of the pumping. Typically, the pump is configured to maintain the pressure in the renal vein at a lower value compared to the pressure in the renal vein before the start of the pumping, even after the perfusion of the kidney increases. For some applications, in addition to reducing the pressure in the subject's renal veins and / or increasing perfusion of the subject's kidneys, the blood pump performs ultrafiltration on the subject's blood.

[0535] It is noteworthy that for some applications, due to the reduction in pressure within the renal vein caused by the pumping of the blood in the downstream direction, the renal venous resistance of the subject is reduced according to the physiological mechanism described, for example, by Haddy et al., Circulation Research, 1956, entitled "Effect of elevation of intraluminal pressure on renal vascular resistance," which is incorporated herein by reference. It is further noteworthy that increasing renal perfusion by increasing blood pressure in the subject's multiple renal arteries does not generally affect the above physiological mechanism.

[0536] In general, when blood pumps as described herein are used to reduce pressure within the subject's renal veins, the response by the subject is expected to be improved over that of administering a diuretic to the subject due to the reduction in renal vein pressure. Thus, for some applications, a reduced diuretic dose may be administered to the subject relative to a diuretic dose that would be administered to the subject if the techniques described herein were not performed. Alternatively, a conventional diuretic dose may be administered to the subject, but the diuretic may have a better effect on the subject due to the reduction in renal vein pressure.

[0537] High central venous pressure results in a high level of blood pressure within the heart, which in turn results in the subject releasing atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP), both of which act as natural diuretics. In general, when blood pumps as described herein are used to reduce pressure within the subject's renal veins, the response by the subject is expected to be more improved than by the release of the subject's natural diuretics due to the reduced renal vein pressure. For some applications, since the subject's central venous pressure is not reduced by the blood pumps described herein, even when the subject's renal vein pressure is reduced by the use of the blood pumps described herein, it is expected that the subject will continue to release atrial natriuretic peptide and B-type natriuretic peptide. Thus, for some applications, utilizing the multiple blood pumps described herein may result in sustained release of atrial natriuretic peptide and B-type natriuretic peptide in the subject and in the effect of the aforementioned natural diuretics being greater than the effect of the diuretics when the multiple blood pumps are not used.

[0538] For some applications, a pressure and / or flow sensor is disposed at the distal end of the catheter, and the suction pressure applied to the renal vein by the pump is modulated in response to feedback from the pressure and / or flow sensor. For example, a first pressure sensor 35 may be disposed on the side of the occlusion member proximal to the kidney, and a second pressure sensor 37 may be disposed on the side of the occlusion member proximal to the vena cava. When the pumping of the pump begins, the flow rate of the pumping is modulated (e.g., automatically, or manually) so that the pressure measured by the first sensor (indicating the pressure in the renal vein) is the same as the pressure measured by the second sensor (indicating the central venous pressure). When the pressure measured at the first sensor is the same as that measured at the second sensor, the pump control unit interprets the flow rate of the pumping to indicate the native blood flow rate from the subject's renal vein to the subject's vena cava because the renal vein pressure was the same as the central venous pressure before the occlusion member was inserted into the renal vein. For some applications, the pump control unit assigns the measured flow rate as a baseline flow rate. Subsequently, when the pump is activated to reduce the pressure in the renal vein relative to the central venous pressure, the pump control unit measures the flow rate of the pumped blood relative to the assigned baseline flow rate.

[0539] For some applications, a third sensor (e.g., a non-invasive blood pressure sensor, or an invasive blood pressure sensor) is used to measure the subject's arterial blood pressure. As described above, when the pumping of the pump begins, the flow rate of the pumping is modulated so that the pressure measured by the first sensor is the same as the pressure measured by the second sensor. When the pressure measured at the first sensor is the same as that measured at the second sensor, the pump controller determines a baseline measure of the subject's renal vascular resistance by measuring the difference between the measured arterial and venous pressures and distinguishing the difference by the baseline flow rate. Subsequently, when the pump is activated to reduce the pressure in the renal vein relative to the central venous pressure, the pump control unit measures the current renal vascular resistance relative to the assigned baseline renal vascular resistance (based on the current difference between the measured arterial and venous pressures and the current flow rate).

[0540] Figure 4B A set of graphs of the central venous flow rate distribution and renal venous pressure distribution of the subject suffering from congestive heart failure after the blood pump 32 and the occlusion member 36 are placed in the left and right renal veins 32 of the subject and the pumps are activated relative to the subject's electrocardiogram cycle is shown according to certain applications of the present invention. The renal venous pressure graphs show the original venous pressure distribution as a dashed curve, and two curves are shown to show the renal venous pressure after the pumps and the occlusion members are placed in the veins and the pumps are activated. Generally, the height of the venous pressure curve after the pumps and the occlusion members are placed in the veins and the pumps are activated is based on the rate of the draw applied to the renal veins by the operator through the pumps. Therefore, two curves show the renal venous pressure after the pumps and the occlusion members are placed in the veins and the pumps are activated. As shown, placing the pumps and occlusion members in the veins and activating the pumps substantially results in a reduction and flattening of the renal vein pressure profile, even if the subject's central venous pressure is elevated. For some applications, the renal vein pressure profile is not completely flat because, although the pumps provide a certain amount of suction pressure to the renal veins throughout the duration of the subject's cardiac cycle, small cyclic variations in blood pressure are transmitted to the renal veins through the renal capillary system. Alternatively, after placing the pumps and occlusion members in the veins and activating the pumps, the renal vein pressure profile is flattened.

[0541] Please refer to Figure 5A -D, which is a schematic diagram of a reverse valve 40 disposed around a blood pump catheter 42 according to some applications of the present invention. The reverse valve 40 is a reference Figure 4A -B An example of the occlusive member 36 described above, and the blood pump catheter 42 are referenced Figure 4A -B An example of the blood pump 34 described above.

[0542] The inverse valve 40 generally comprises a rigid stent 44 configured to anchor the inverse valve to the renal vein 32. Figure 5A -B, the reverse valve 40 is shown in the left renal vein, but the scope of the invention includes placing the reverse valve 40 and blood pump catheter 42 in the right renal vein and, as is typically the case, in each of the subject's multiple renal veins.) The reverse valve 40 may also include a plurality of valve leaflets 46. In response to blood pressure on the upstream side of the plurality of valve leaflets exceeding the pressure on the downstream side of the plurality of valve leaflets, the plurality of valve leaflets are configured to open by dividing the wall of the blood vessel (and generally by dividing the rigid support of the valve) to allow blood to flow in an antegrade direction between the plurality of cusps of the plurality of valve leaflets and an inner wall of the blood vessel. In this sense, the inverse valve is inversely proportional to a conventional vascular valve, wherein the plurality of leaflets are configured to open through the plurality of cusps of the plurality of leaflets separated from one another in order to allow blood flow between the plurality of leaflets in response to the blood pressure on the upstream side of the plurality of valve leaflets exceeding the pressure on the downstream side of the plurality of valve leaflets. Furthermore, a typical vascular valve is arranged in the blood vessel so that the plurality of valve leaflets converge toward each other in the downstream direction, and as Figure 5A As shown in -B, the plurality of leaflets 46 of the valve 40 diverge from each other in the downstream direction.

[0543] Figure 5A The inverse valve is shown in an open state, with arrows 48 indicating blood flow in an antegrade direction between the cusps of the valve leaflets and an inner wall of the renal vein 32. Typically, when the inverse valve 40 and blood pump catheter 42 are placed in the renal vein, and the blood pump catheter is not activated, the valve leaflets will open to allow blood flow from the renal vein to the vena cava in response to the blood pressure in the renal vein exerting pressure on the upstream side of the leaflets 46.

[0544] Figure 5BThe reverse valve 40 is shown in the closed state. As shown, in the closed state of the valve, the valve occludes blood flow from the renal vein to the vena cava by the plurality of cusps of the plurality of valve leaflets 46 contacting the inner wall of the renal vein at an occluded position 49. For some applications, when in the occluded state of the valve, the plurality of cusps of the plurality of valve leaflets contact a portion of the rigid support of the valve. Typically, the valve closes in response to the blood pressure on the downstream side of the plurality of valve leaflets exceeding the pressure on the downstream side of the plurality of valve leaflets. When the catheter blood pump is activated, the pump draws blood in a downstream direction from a location on the upstream side of the valve and draws blood back to the venous system at a location on a downstream side of the valve. For example, the catheter blood pump may define a plurality of inlet holes 50 that flow through an upstream side of the valve and through which blood is pumped into the pump, and the catheter blood pump may also define a plurality of outlet holes 52 that flow through the downstream side of the valve and through which blood is pumped into the renal vein or the vena cava. For some applications, the catheter blood pump pumps blood using an impeller disposed within a lumen 56 defined by the catheter blood pump, as shown.

[0545] For some applications, blood pump catheter 42 is connected to support 44 of valve 40 before blood pump catheter 42 and valve 40 are inserted into the body of the subject. The pump is connected to the valve support so that, when placed in the renal vein, multiple inlet holes 50 communicate with an upstream side of multiple valve leaflets 46, and multiple outlet holes 52 are arranged to communicate with the downstream side of the valve. For some applications, valve 40 and blood pump catheter 42 are inserted separately into the renal vein of the subject. For example, the valve can be inserted into the renal vein, and then the blood pump catheter can be inserted through the valve so that the blood pump catheter becomes connected to valve support 44. Or the blood pump catheter can be inserted into the renal vein, and then the valve can be inserted into the renal vein and beyond the blood catheter. Typically, the blood pump and the valve support define a connection mechanism connecting the blood pump conduit to the valve support such that a plurality of inlet holes 50 communicate with an upstream side of a plurality of valve leaflets 46, and such that a plurality of outlet holes 52 are provided to communicate with the downstream side of the valve.

[0546] Typically, the blood pump catheter 42 is configured to pump blood into the renal vein in a manner that places the reverse valve 40 in one of its occluded states and / or maintains the reverse valve 40 in one of its occluded states. For example, the blood pump catheter can be configured to pump blood out of the multiple output holes 52 in a manner that the blood flow outside the multiple output holes directly impacts the multiple downstream sides of the multiple valve leaflets 46 so that the multiple cusps of the multiple leaflets are in and / or maintained in contact with the inner wall of the renal vein. Therefore, the hydrodynamic pressure of the blood pumped into the subject's blood vessel causes the cusps of the multiple leaflets to be in and / or maintained in contact with the inner wall of the renal vein. For certain applications, the blood pump catheter is structurally configured in the manner described above to pump blood out of the multiple output holes, for example, according to the multiple applications of the present invention described above and with reference to Figure 6B Typically, valve 40 and blood pump catheter 42 are configured such that in response to the blood pump catheter becoming inoperative (e.g., due to lack of power for the pump), valve leaflets 46 will open to allow blood flow from the renal vein to the vena cava in response to pressure exerted on the upstream side of the valve leaflets by blood in the subject's renal vein.

[0547] As described above, for some applications, the blood pump catheter 42 is configured to pump blood out of the plurality of outlet orifices 52 in such a manner that the blood flow out of the plurality of outlet orifices directly impinges upon the plurality of downstream sides of the plurality of valve leaflets 46. For some applications, pumping the blood directly toward the plurality of downstream sides of the plurality of valve leaflets has an anticoagulant effect by flushing the leaflets with the blood pumped toward the leaflets, and reduces the buildup of blood clots and / or tissue growth on the plurality of valve leaflets relative to if the blood is not pumped directly toward the plurality of valve leaflets. Alternatively or in addition, along with pumping the blood directly toward the plurality of leaflets, the blood pump catheter pumps an anticoagulant directly toward the plurality of leaflets. For some applications, by pumping an anticoagulant directly toward the plurality of leaflets, a higher dose of the anticoagulant is provided to the plurality of leaflets than, for example, if the anticoagulant is administered systemically to the subject. Thus, the amount of the anticoagulant administered to the subject can be reduced relative to if the anticoagulant was administered systemically to the subject, and / or the anticoagulant can be more effective in reducing blood clots and / or tissue growth at the plurality of leaflets relative to if the anticoagulant was administered systemically to the subject. For some applications, the plurality of valve leaflets define a plurality of apertures configured to allow the flow of the anticoagulant therethrough to the plurality of upstream sides of the plurality of valve leaflets.

[0548] according to Figure 5A -B, the combination of the reverse valve 40 and the blood pump conduit 42 is thus configured so that: (a) when the blood pump is not functioning, the reverse valve opens in response to pressure exerted by blood in the renal vein on the upstream sides of the multiple valve leaflets, and (b) when the blood pump is functioning, the pumping of blood into the renal vein on the downstream side of the multiple leaflets 46 maintains the valve in an occluded state.

[0549] Figure 5C -D is a schematic diagram of multiple views of the upstream ends of the reversing valve 40 and the blood pump conduit 42 when the valve is in a non-occluded state and an occluded state, respectively. Figure 5C As shown, when the valve is in its non-occlusive state, the cusps 58 of the leaflets 46 are separated from the valve support to allow blood to flow between the cusps of the leaflets and the inner wall of the blood vessel (the blood vessel is not shown). It is worth noting that for some applications, the structure of the valve support is similar to Figure 5C -D. For example, the valve support may have Figure 5A -A structure shown in B, so that even when the valve is in its occluded state, the multiple cusps of the multiple leaflets do not directly contact a portion of the valve support, but contact the inner wall of the blood vessel.

[0550] Please refer to Fig. 6A -G, which is a schematic diagram of multiple configurations of the blood pump catheter used with the reversing valve 40 according to certain applications of the present invention.

[0551] Fig. 6AA control unit 60 is shown for controlling pumping of a blood pump catheter 42. The plurality of dashed boxes 62 indicate a plurality of locations of the blood pump motor, in accordance with respective applications of the invention. For some applications, the blood pump motor is located at the location indicated by box 62A, outside the subject's body, and in the vicinity of the pump control unit (e.g., in the same housing as the pump control unit). For some applications, the motor being located outside the subject's body allows for the use of a smaller diameter catheter for the blood pump catheter than would be required if the motor were located within the catheter. Alternatively, the blood pump motor is located at the location indicated by box 62B, such that when the distal end of the blood pump catheter is located within the renal vein 32, the motor is located within the vena cava. For some applications, the motor being located within the portion of the catheter located within the vena cava allows for the distal portion of the catheter within the renal vein to be placed smaller than would be required if the motor were located within the distal portion of the catheter. Alternatively, the blood pump motor is located at the position indicated by box 62C, within the distal portion of the catheter placed in the renal vein. For some applications, the blood pump motor is located within the vicinity of impeller 54 (e.g., at the position indicated by box 62C) in order for the pump motor to impart rotational motion to the impeller more efficiently than if the blood pump motor were located at a greater distance from the impeller 54.

[0552] Figure 6B -D are schematic diagrams of the blood pump catheter 42, wherein the pump structure is configured to pump blood out of the output holes 52 in a manner to maintain the reverse valve 40 in a closed state.

[0553] like Figure 6B As shown, for some applications, the plurality of output holes are located so that, when the blood pump catheter is placed through (or connected to) the valve and the plurality of access holes 50 are disposed to flow through the upstream side of the valve, the plurality of output holes are disposed adjacent to the plurality of bases 64 of the plurality of valve leaflets 46. For example, the plurality of output holes of the pump may be disposed adjacent to a position along the length of the plurality of valve leaflets below midway between the plurality of cusps 58 of the plurality of leaflets and the plurality of bases 64 of the plurality of leaflets. Typically, due to the arrangement of the plurality of output holes relative to the plurality of valve leaflets, blood flowing out of the plurality of output holes flows relative to the plurality of downstream sides of the plurality of valve leaflets 46, thereby maintaining the plurality of cusps of the plurality of leaflets in contact with the inner wall of the renal vein, for example, to maintain the valve in an occluded (closed) state.

[0554] For some applications, the blood pump catheter is configured to define a radial projection 66 that is concave therefrom and curves toward a distal end of the catheter, such as Figure 6C . The curvature and arrangement of the projection 66 are typically such that a first end of the projection connected to the catheter is disposed proximally to the plurality of output holes 52, and the other end of the radial projection is disposed distally to the plurality of output holes. Typically, blood flowing outside the plurality of output holes is directed through the radial projection 66 toward the plurality of downstream sides of the plurality of valve leaflets 46, so that the plurality of cusps of the plurality of leaflets maintain contact with the inner wall of the renal vein, for example, thereby maintaining the valve in an occluded (e.g., closed) state.

[0555] For some applications, the plurality of output holes 52 are configured to direct blood at a distance and outside of the plurality of holes (e.g., toward the upstream end of the catheter pump). Fig.6D As shown in , the surfaces 68 defining the plurality of holes can be curved toward the distal end of the pump catheter. Thus, the blood flowing out of the plurality of output holes is directed toward the downstream sides of the plurality of valve leaflets 46 so that the cusps of the plurality of leaflets maintain contact with the inner wall of the renal vein, for example, thereby maintaining the valve in an occluded (e.g., closed) state.

[0556] Fig. 6E -G illustrates a stent 40 for supporting the reverse valve 40 in the renal vein as an alternative or additional stent 40 (e.g. Figure 5A -D).

[0557] For some applications, valve 40 is a three-leaflet valve. Alternatively, the valve can be a two-leaflet valve, or can have more than three leaflets. The plurality of leaflets maintain contact with the renal vein at the plurality of commissures of the plurality of valve leaflets. Between the plurality of commissures of the plurality of valve leaflets, when the valve is in the occluded state of the valve, the plurality of cusps of the plurality of valve leaflets contact the renal vein wall, and when the valve is in the non-occluded state of the valve, the plurality of cusps of the plurality of valve leaflets separate from the renal vein wall to allow blood flow between the plurality of valve leaflets and the renal vein wall.

[0558] For some applications (e.g. Figure 5A -D), the plurality of valve leaflets are connected to a valve support 48 located at the plurality of confluences of the plurality of valve leaflets, and the valve support maintains the plurality of confluences of the plurality of valve leaflets in contact with the renal vein wall. Alternatively or additionally, as Fig. 6E, a slit tube 72 is pushed over a blood pump catheter 42. The tube is configured so that when the distal end of the tube is pushed toward the distal end of the catheter, the portions of the tube between the slits expand radially outward. The radially expanded portions of the tube are configured to maintain the confluences of the valve leaflets in contact with the renal vein wall.

[0559] Alternatively or additionally, a balloon 74 having a star-shaped cross-section (e.g., a three-pointed star-shaped cross-section, as shown) is disposed around the portion of the blood pump catheter 42 disposed within the valve 40. Various views of the balloon 74, the blood pump catheter 42, and the valve 40 are shown in FIG. Fig. 6F -G. For some applications, the three-dimensional shape of the balloon, when the balloon is in its inflated state, is similar to the shape of a carambola (e.g., a star-shaped fruit). Typically, the balloon is inflated so that the balloon maintains the confluences of the valve leaflets in contact with the renal vein wall at the plurality of points of the star-shaped cross-section of the balloon.

[0560] As described herein, typically, the reversing valve 40 and the blood pump catheter 42 are used to provide an acute treatment to a subject. For example, the reversing valve and the blood pump catheter may be placed in the renal veins of the subject for a period of more than one hour (e.g., more than one day), less than one week (e.g., less than four days), and / or between one hour and one week (e.g., between one day and four days). For some applications, after the termination of the treatment, the slit tube 72 or balloon 74 is used to maintain the valve confluences in contact with the renal vein wall to facilitate removal of the valve from the renal vein. For example, to remove the valve from the renal vein, the slit tube may be retracted so that the radially expanded portions of the tube are compressed and the valve leaflets no longer maintain contact with the renal vein wall, and / or the balloon 74 may be inflated so that the valve leaflets no longer maintain contact with the renal vein wall.

[0561] Please refer to Fig. 7A -B, which is a schematic diagram of a blood pump catheter 42 and a non-reciprocating valve 80 according to certain applications of the present invention, when the non-reciprocating valve is in its closed and open states, respectively. In certain applications, as an alternative to placement through a reciprocating valve, the blood pump catheter 42 is inserted through a non-reciprocating valve, such as Fig. 7A -B. The non-reversing valve 80 is the same as the one mentioned above. Figure 4A -B is an example of an occlusive member 36. A non-reversible valve typically includes a rigid support 82 and a plurality of valve leaflets 84.

[0562] Typically, the blood pump catheter 42 is used to draw blood in a downstream direction from a location on an upstream side of the plurality of valve leaflets 84 to a location on a downstream side of the plurality of valve leaflets 84, such as a location within the vena cava or a location within the renal vein. In response to the pressure on the downstream side of the plurality of valve leaflets exceeding the pressure on the upstream side of the plurality of valve leaflets, the valve 80 is configured to contact the catheter through the plurality of cusps 86 of the plurality of valve leaflets to prevent backflow of blood. In response to the pressure on the upstream side of the plurality of valve leaflets exceeding the pressure on the downstream side of the plurality of valve leaflets, the valve 80 is also configured to separate from the catheter through the plurality of cusps of the plurality of leaflets to allow the blood to flow across the valve, thereby allowing blood to flow between the plurality of leaflets and the blood pump catheter in the direction of arrow 88 ( Fig. 7A ).

[0563] For some applications, initially, a valve (e.g., a reverse valve, such as Figure 5A -D and 6A-G, or a non-reversing valve, such as Fig. 7A -B) and a pump are used to treat the subject. Subsequently (e.g., after a period of more than one hour, less than one week, and / or after between one hour and one week), the pump is removed from the subject's renal vein and the valve is left in place within the renal vein. The valve is configured to reduce pressure within the subject's renal vein by preventing backflow of blood from the subject's vena cava into the subject's renal vein and allowing blood to flow from the subject's renal vein to the subject's vena cava, even in the absence of the pump, relative to renal pressure within the subject's renal vein in the absence of the valve. Thus, for some applications, the valve is left in place within the renal vein even after the subject's acute treatment (using the pump in combination with the valve) has terminated in order to provide long-term treatment for the subject.

[0564] Please refer to Fig. 8A -B, which is a schematic diagram of various views of a blood pump 90 according to some applications of the present invention. The pump 90 is the above-mentioned reference Figure 4A -B is an example of both the occlusion member 36 and the pump 34, since the pump 90 when placed in the renal vein of the subject is configured to both occlude the renal vein and draw blood downstream from a location on an upstream side of the pump to a location on a downstream side of the pump.

[0565] Pump 90 includes an outer tube 92, the outer surface of the tube being configured to contact the inner wall of the renal vein. Typically, outer tube 92 includes a stent having a material (typically, a blood-impermeable material) disposed thereon. First and second one-way valves 94 and 96 are disposed at respective ends of the tube, the valves permitting blood to flow into and out of the tube only in the downstream direction. A membrane 98 is connected to the interior of the tube so that the membrane divides the tube into a first compartment 100 through which the valves flow, and a second compartment 102 through which the valves do not flow. A pumping mechanism 104, such as an electromagnetically driven pumping mechanism, cyclically drives the membrane to move relative to the tube so that the relative sizes of the first and second compartments change.

[0566] Please refer to Fig.9A -D, which is a schematic diagram of various stages of an operating cycle of the blood pump 90 according to some applications of the present invention. Fig.9A The blood pump is shown at an arbitrary starting point in the operating cycle of the blood pump, at which point both valve 94 and valve 96 are closed. FIG. 9A to FIG. 9B and Figures 9B to 9C As shown in the transition period of FIG. 1 , the pumping mechanism 104 moves the membrane 98 to increase the volume of the first compartment 100, for example, by pumping fluid (air or saline) outside the second compartment by the pumping mechanism. The increase in the volume of the first compartment reduces the pressure in the first compartment relative to the pressure on the upstream side of the first valve 94, causing the valve 94 to open and blood to be drawn into the first compartment. Subsequently, the pumping mechanism moves the membrane to increase the volume of the second compartment, for example, by pumping fluid into the second compartment, such as from FIG. 9C to FIG. 9D and Figures 9D to 9A The transition period of the pump 90 is shown in FIG. 1 . The movement of the membrane causes the volume of the first compartment to decrease and the pressure in the first compartment to increase. The pressure in the first compartment causes valve 94 to close and valve 96 to open and allow the blood in the first compartment to flow to the downstream side of the pump 90.

[0567] Please refer to Fig. 10A-D, which is a schematic diagram of a blood-impermeable sleeve 110 configured to occlude blood flow from a subject's vena cava 26 to the subject's multiple renal veins 32 according to certain applications of the present invention. Typically, the sleeve is placed in the vena cava so that a downstream end 112 of the sleeve is connected to the wall of the vena cava at a first location 114 downstream of all of the subject's renal veins (e.g., the left and right renal veins in a typical subject with two renal veins), and so that an upstream end 116 of the sleeve is connected to a wall of the vena cava at a second location 118 upstream of all of the subject's renal veins. Thus, the sleeve isolates the blood in the multiple renal veins into a compartment that separates blood flow through the vena cava. Typically, a rigid structure, such as a stent 120 as shown, is configured to connect the upstream and downstream ends of the sleeve to the vena cava.

[0568] A pump 122 is configured to draw blood from a location outside of the sleeve 110 (e.g., from the separated compartments) to a location inside the sleeve (e.g., a location within the vena cava upstream or downstream of the sleeve). Thus, the pump draws blood outside of the subject's renal veins and into the subject's vena cava. The sleeve prevents backflow of blood from the vena cava into the renal veins.

[0569] For some applications, as shown, the support 120 defines a plurality of flared ends thereof. The sleeve 110 also defines a plurality of flared ends thereof. If the pressure in the vena cava is greater than or equal to the pressure in the plurality of renal veins, the plurality of flared ends of the sleeve are configured to occlude blood flow from the vena cava to the plurality of renal veins by contacting the wall of the vena cava. For some applications, at least one of the plurality of flared ends of the sleeve is configured to act as a valve, such as by providing blood flow from outside the sleeve to the vena cava to relieve pressure and / or a blood spill outside the sleeve. In response to the blood pressure in the plurality of renal veins exceeding the blood pressure in the vena cava, the flared end of the sleeve is configured to at least partially separate from the wall of the vena cava to allow the blood to flow between the outer side of the flared end of the sleeve and the inner wall of the vena cava. For some applications, the upstream and downstream ends of the sleeve are configured to act as a valve in a manner similar to that described above. Fig. 10A The sleeve is shown when the upstream and downstream ends of the sleeve are closed to occlude the blood flow between the exterior of the sleeve and the wall of the vena cava. Fig. 10BThe sleeve is shown with the upstream and downstream ends of the sleeve open to allow the blood flow from the renal veins to the vena cava and between the exterior of the sleeve and the wall of the vena cava.

[0570] like Fig. 10A -B and Fig. 10D As shown in , for some applications, a pump housing sleeve 124 protrudes from the exterior of one of the plurality of flared ends of sleeve 110 (e.g., the downstream flared end of sleeve 110, as shown). The pump housing sleeve is configured to facilitate insertion of pump 122 therethrough. The pump housing sleeve is configured to form a seal around the pump so that there is minimal or zero blood flow between the exterior of the pump and the interior of the pump housing sleeve. For some applications (not shown), a pump housing sleeve is not used to form a seal around the exterior of the pump, and the flared end of the sleeve defines an opening (e.g., a hole) through which the pump is inserted, the opening being sized so that the interface between the exterior of the pump and the flared distal end of the sleeve is closed.

[0571] It is noted that while the pump receiving sleeve is shown protruding from the exterior of the flared upstream end of the sleeve, for some applications, the pump is inserted through the downstream flared end of the sleeve, and the downstream flared end of the sleeve defines a pump receiving sleeve, or an aperture through which the pump is inserted. Generally, the scope of the present invention includes inserting the blood pumps and occlusion members described herein toward the renal veins via the renal veins through the vena cava, from above the renal veins or from below the renal veins. For example, the renal veins may be accessed via the vena cava in the upstream direction of the femoral vein or via the downstream direction of the jugular vein.

[0572] Depending on the application, pump 122 pumps blood into the vena cava at a location upstream or downstream of the sleeve. For some applications, the pump pumps the blood into the vena cava at a location downstream of the sleeve to reduce the blood flow through the sleeve relative to if the pump pumped the blood into the vena cava at a location upstream of the sleeve. For some applications, an advantage is that the blood flow through the sleeve in the aforementioned manner is reduced because the sleeve acts as a resistor to blood flow through the sleeve. As described above, and for example, Fig. 10D As shown, for some applications, a guide wire 126 is positioned where the pump draws blood into the vena cava at a location upstream of the sleeve.

[0573] For some applications, sleeve 110 and stent 120 are inserted into the vena cava of the subject while a guide wire 126 is disposed within pump housing sleeve 124. After anchoring sleeve 110 and stent 120 to the vena cava, pump 122 is inserted through the pump housing sleeve by disposing the pump outside the guide wire.

[0574] like Fig. 10C As shown, for some applications, the stent 120 is configured to define a sleeve-supporting stent 128 that is generally configured to conform to the shape of the sleeve. Typically, the sleeve-supporting stent is configured to define a plurality of widened ends 130 and a narrow central portion 132 elongated between the plurality of widened ends 130, the plurality of flared ends elongated from the plurality of ends of the narrow central portion. In addition, the stent defines a vessel-wall-supporting stent 134 that is connected to the narrow central portion of the sleeve-supporting stent and that protrudes radially outward from the plurality of sides of the narrow central portion of the sleeve-supporting stent.

[0575] For some applications, pumping of blood from outside the sleeve through pump 122 causes the walls of the vena cava to be pulled inward. Vessel-wall-supporting stent 134 supports the inner wall of the vena cava and prevents the inner wall of the vena cava from collapsing around the narrow central portion 132 of the stent's sleeve-supporting stent 128. Typically, during operation of the pump, the pump head, including the plurality of holes 125 of the pump head, is disposed within the gap between the narrow central portion of the sleeve-supporting stent of the stent (which supports the sleeve) and the vessel-wall-supporting stent (which supports the wall of the vena cava).

[0576] As described above, for some applications, the pumping of blood from the exterior of the sleeve by pump 122 causes the walls of the vena cava to be compressed by being pulled inward. For some applications, the pump is configured to anchor stent 120 to the vena cava by applying a suction force to the vena cava, thereby compressing the vena cava around at least a portion of the stent. For some applications, a stent that is not substantially oversized relative to the vena cava and / or a stent having a diameter smaller than the vena cava is anchored to the vena cava due to the suction force applied to the vena cava by the pump, thereby compressing the vena cava around at least a portion of the stent.

[0577] As described above, typically, the sleeve-support bracket 128 is configured to generally conform to the shape of the sleeve. The sleeve and the sleeve-support bracket define a narrow central portion diameter D1 ( Fig. 10C), and a maximum diameter D2 at the ends of the flared ends of the sleeve. For some applications, D1 is greater than 8 mm, less than 35 mm, and / or between 8 and 35 mm. For some applications, D2 is greater than 10 mm, less than 45 mm, and / or between 10 and 45 mm. For some applications, the ratio of D2:D1 is greater than 1.1:1, less than 2:1, and / or between 1.1:1 and 2:1. For some applications, an overall length L1 of the sleeve is greater than 6 mm, less than 80 mm, and / or between 6 and 80 mm. For some applications, a length L2 of the flared ends of the sleeve (e.g., the length from the location where the sleeve begins to flare to the end of the sleeve) is greater than 3 mm, less than 40 mm, and / or between 3 and 40 mm. For some applications, a length L3 of the narrow central portion of the sleeve and the sleeve-support bracket is greater than 3 mm, less than 70 mm, and / or between 3 and 70 mm.

[0578] For some applications, a maximum diameter D3 of the vessel-wall-supporting stent 134 of the stent 120 is greater than 10 mm, less than 50 mm, and / or between 10 and 50 mm. For some applications, a ratio of D3:D1 is greater than 1.1:1 (e.g., greater than 1.5:1, or greater than 2:1), less than 5:1, and / or between 1.1:1 and 5:1.

[0579] For some applications, an inner diameter D4 ( Fig. 10A ) is greater than 2 mm, less than 10 mm, and / or between 2 and 10 mm. For many applications, wherein sleeve 110 defines an opening through which pump 122 is inserted, the diameter of the opening through which pump 122 is inserted is typically greater than 2 mm, less than 10 mm, and / or between 2 and 10 mm.

[0580] For some applications, the pump 122 is substantially similar to the catheter blood pump 42 described above, for example, with reference to Figure 5A -D. For example, in Fig. 10D As described in the drawings, the blood pump may include an impeller 123 to pump blood. Blood is drawn from the renal veins into the catheter through a plurality of inlet holes 125, which are disposed between the exterior of the sleeve and the wall of the vena cava, and through a plurality of outlet holes 127 disposed in the vena cava to pump blood into the vena cava, for example at a location upstream of the sleeve, such as Fig. 10D As described in.

[0581] Please refer to Fig. 10E-F, which is a schematic diagram of connecting a blood-impermeable sleeve 135 to the vena cava 26 using a spiral support configured to occlude blood flow from the subject's vena cava to the subject's multiple renal veins 32 according to certain applications of the present invention. According to various applications, the spiral support is an inflatable spiral support (e.g., a spiral balloon), or a spiral support made of a shape memory alloy, such as nitinol. Typically, the spiral support is connected to the vena cava so that a downstream end of the spiral support is connected to the wall of the vena cava at a first location 114 downstream of all of the subject's renal veins (e.g., the left and right renal veins in a typical subject with two renal veins) and so that an upstream end of the spiral support is connected to a wall of the vena cava at a second location 118 upstream of all of the subject's renal veins. Thus, the spiral support separates the blood in the multiple renal veins into a compartment outside the sleeve that separates blood flow through the vena cava. It is worth noting that sleeve 135 need not have multiple flared ends configured to occlude blood flow from the vena cava to the multiple renal veins by contacting the wall of the vena cava. Instead, as shown in the figure, the spiral support can occlude the blood flow from the vena cava to the multiple renal veins by contacting the wall of the vena cava. Alternatively, sleeve 135 has the above-mentioned reference Fig. 10A -D, a substantially identically shaped sleeve 110 defining flared ends configured to contact the wall of the vena cava.

[0582] Typically, a blood pump catheter 137 is inserted into the vena cava via a delivery device 138 ( Fig.10F ). FIG. 10E to FIG. 10FAs shown in the transition of , for some applications, the blood pump catheter is guided into the compartment outside the sleeve by being pushed beyond the spiral support. For some applications, a distal portion of the blood pump catheter is configured to assume a spiral shape automatically when being pushed outside the delivery device. Alternatively, the distal portion of the blood pump catheter is treated as assuming a spiral shape by being pushed outside the spiral support. Typically, the blood pump catheter defines a plurality of access holes 139 along a majority (e.g., more than 50 percent, or more than 75 percent of the length) of the distal portion of the blood pump catheter (e.g., the portion of the blood pump catheter placed in the compartment outside the sleeve by being pushed beyond the spiral support). The blood pump catheter draws blood outside the compartment outside the sleeve (e.g., outside the plurality of renal veins) into the plurality of access holes. The blood pump is typically configured to have a plurality of output holes (not shown) disposed in the vena cava that flows through the interior of the sleeve (e.g., at a location in the vena cava upstream of the sleeve, or at a location in the vena cava downstream of the sleeve). The pump draws blood into the vena cava through the plurality of output holes.

[0583] Please refer to Figure 10G , which is a schematic diagram of a blood-impermeable sleeve 141 connected to a spiral blood pump catheter 143 according to some applications of the present invention, wherein the sleeve and the blood pump catheter are configured to occlude blood flow from the subject's vena cava 26 to the subject's multiple renal veins 32. The sleeve 141 is typically configured to define its multiple flared ends 145, as shown. Typically, the sleeve 141 has a substantially similar Fig. 10A -D-shaped sleeve 110, which defines multiple flared ends configured to contact the wall of the vena cava.

[0584] Sleeve 141 and blood pump catheter 143 are inserted into the vena cava via a delivery device 149. A distal end of the catheter 143 (e.g., the end of the catheter that is farthest from an insertion site through insertion of the catheter into the body of the subject) is connected to a distal end of the sleeve (e.g., a downstream end of the sleeve, as shown) at a connection location 147. The blood pump catheter is pre-configured so that when pushed outside the distal end of the insertion device, a distal portion of the catheter assumes a helical shape disposed around the exterior of the sleeve. Typically, by assuming the helical shape, the distal portion of the catheter axially holds the sleeve open (e.g., prevents axial collapse of the sleeve). For some applications, a ring 151 made of a shape memory alloy material (e.g., Nitinol) is connected to the proximal end of the sleeve and is configured to support the proximal end of the sleeve. Typically, the blood pump catheter defines a plurality of access holes 153 along a majority (e.g., more than 50 percent, or more than 75 percent) of the length of the distal portion (e.g., the spiral portion of the blood pump catheter disposed around the sleeve) of the blood pump catheter. The blood pump catheter draws blood from outside the sleeve (e.g., outside the renal veins) into the plurality of access holes. Typically, the sleeve is placed in the vena cava so that a downstream end of the sleeve is connected to the wall of the vena cava at a first location 114 downstream of all of the subject's renal veins (e.g., the left and right kidneys in a typical subject having two renal veins) and so that an upstream end of the sleeve is connected to the wall of the vena cava at a second location 118 upstream of all of the subject's renal veins. Also typically, the drawing of blood into the plurality of access holes compresses the vena cava around the exterior of the sleeve such that blood within the plurality of renal veins becomes isolated in a compartment outside the sleeve separated from blood flow by the vena cava.

[0585] The blood pump is typically configured to have a plurality of output holes (not shown) disposed in the vena cava that flows through the interior of the sleeve (e.g., at a location in the vena cava upstream of the sleeve, or at a location in the vena cava downstream of the sleeve). The pump draws blood into the vena cava through the plurality of output holes.

[0586] It is worth noting that although Fig. 10E-G, the blood pump is shown inserted from the upstream end of the sleeve to the outside of the sleeve, and for some applications, the blood pump is inserted from the downstream end of the sleeve to the outside of the sleeve. Generally, the scope of the present invention includes inserting the multiple blood pumps and the multiple occlusion members described herein toward the multiple renal veins by passing through the multiple renal veins through the vena cava, from above the multiple renal veins or from below the multiple renal veins. For example, the multiple renal veins can be accessed by passing through the vena cava from the upstream direction of the femoral vein or through the downstream direction of the jugular vein.

[0587] Please refer to Fig.11A -C, which is a schematic diagram of a blood pump catheter 42 placed in a subject's renal vein 32 according to certain applications of the present invention, such that an orifice-covering umbrella 140 disposed around the exterior of the catheter covers an orifice located at a confluence 142 between the subject's vena cava 25 and the renal vein 32. It is noteworthy that although the orifice-covering umbrella is described as an "umbrella", the scope of the present invention includes covering the orifice with any orifice-covering member configured around the exterior of the catheter and made of multiple elastic portions (e.g., multiple elastic tissue portions), and providing shape and structure to the multiple rigid support members of the orifice-covering member. The orifice-covering umbrella 140 is the above-mentioned reference Figure 4A -B is an example of an occlusive member 36, and a blood pump catheter 42 is the above-mentioned reference Figure 4A - An example of a blood pump 34 of B. (In Fig.11A -C, an orifice-covering umbrella 140 is shown covering the left renal vein orifice, but the scope of the present invention includes using an orifice-covering umbrella 140 to cover the right renal vein orifice, and, as a typical case, placing an orifice-covering umbrella at the opening of the multiple confluences of the vena cava and each of the left and right renal veins.)

[0588] like Fig.11A As shown in FIG. 1-C, the blood pump catheter 42 and the orifice-covering umbrella 140 are inserted into the vena cava 26 through an insertion device 144. During the insertion, the orifice-covering umbrella is typically in a closed state. The blood pump catheter and the orifice-covering umbrella are pushed outside the insertion device, and the orifice-covering umbrella opens to respond to being pushed outside the distal end of the insertion device ( Fig. 11B). The orifice-covering umbrella is placed in the vicinity of the junction 142. The blood pump catheter is activated to pump blood downstream of the plurality of access holes 50 at the distal end of the blood pump catheter through the renal vein. Typically, due to the suction of the blood pump, the orifice-covering umbrella is pulled relative to the wall of the vena cava surrounding the orifice at the junction 142 ( Fig. 11C ).

[0589] Typically, the orifice-covering umbrella 140 blocks the return flow of blood from the vena cava to the renal veins by being pushed relative to the walls of the vena cava surrounding the orifice at the confluence 142. Also typically, when the blood pump is activated, the orifice-covering umbrella blocks blood flow both from the renal veins to the vena cava and from the vena cava to the renal veins due to the suction generated by the blood pump by the orifice-covering umbrella becoming closed relative to the walls of the vena cava surrounding the orifice at the confluence 142. In response to the pump 42 becoming inactive (e.g., due to a loss of power to the pump), the umbrella surrounding the orifice at the confluence allows blood to flow from the renal veins to the orifice in the direction of arrows 146 ( Fig. 11B ) of the vena cava because when the pump is inactive, the umbrella is not closed relative to the multiple walls of the vena cava surrounding the orifice at the confluence 142.

[0590] For some applications, a diameter D5 of the aperture-covering umbrella 140 is greater than 5 mm (e.g., greater than 10 mm, or greater than 20 mm), less than 30 (e.g., less than 25 mm, or less than 20 mm), and / or between 5 and 30 mm (e.g., between 10 and 20 mm, or between 15 and 25 mm) when the aperture-covering umbrella is in its open state.

[0591] Please refer to Figure 12Ai -ii and 12-B, which are schematic diagrams of a blood pump 150 including an impeller 152 disposed within a radially expanding impeller cage 154 according to certain applications of the present invention. Figure 12Ai and 12Aii Various views of the blood pump 150 are shown. Fig. 12C -D, which depicts multiple side views of the blood pump 150 disposed within the renal vein 32 when the cover 154 is respectively in its radially expanded and radially compressed configurations according to certain applications of the present invention. Fig.12E , which illustrates an end view of the impeller 152 in combination with a cross-sectional view of a plurality of struts 204 of the cover 154 and a cross-sectional view of the renal vein 32 when the blood pump is disposed in the renal vein 32 according to certain applications of the present invention.

[0592] It is worth noting that the term "impeller" used herein refers to a bladed rotor, such as Figure 12Ai When the vane rotor is placed in a blood vessel (e.g., the renal vein 32) and rotated, the vane rotor functions as an impeller by virtue of the blood flowing through the blood vessel and / or by virtue of creating a pressure differential between the upstream end and the downstream end of the impeller.

[0593] For some applications, blood pump 150 is placed in one or both of a subject's renal veins and is used to pump blood in a downstream direction through the renal veins toward the vena cava to reduce renal venous pressure and / or enhance perfusion of the subject's kidneys.

[0594] To provide acute treatment to a subject suffering from cardiac insufficiency, congestive heart failure, low renal blood flow, high renal vascular resistance, hypertension, and renal insufficiency, the blood pump 150 is typically placed in the renal veins of the subject. For example, the pump can be placed in the renal veins of the subject for a period of more than one hour (e.g., more than one day), less than one week (e.g., less than four days), and / or between one hour and one week (e.g., between one day and four days). For some applications, to provide chronic treatment to a subject suffering from cardiac insufficiency, congestive heart failure, low renal blood flow, high renal vascular resistance, hypertension, and renal insufficiency, the pump is chronically placed in the renal veins of the subject. For some applications, a chronic treatment is applied to a subject for more than several weeks, months, or years, wherein the pump is intermittently placed in the renal veins of the subject, and the subject undergoes intermittent treatment according to the techniques described herein. For example, the subject can undergo intermittent treatment at intervals of several days, weeks, or months.

[0595] Typically, the effects of pumping blood through the renal veins in a subject suffering from cardiac insufficiency, congestive heart failure, low renal blood flow, high renal vascular resistance, hypertension, and renal insufficiency are substantially similar to those of a control subject. Figure 4B In other words, the extraction causes a decrease and flattening of the renal venous pressure distribution of the subject, even if the central venous pressure of the subject is increased. Figure 4B The renal pressure graph depicts the original venous pressure profile after activation of the blood pump as a curved dashed line. Typically, during the pumping of the blood through the renal vein, the height of the venous pressure curve is based on the amount of pumping applied to the renal vein by the operator through the pump, such as Figure 4BAs indicated by the two curved solid lines shown in , the curves represent renal venous pressure profiles at various rates of pumping of blood pump 150. For some applications, as shown, the renal venous pressure profiles are not completely flat because cyclic changes in blood pressure are transmitted to the renal veins through the renal capillary system.

[0596] Typically, perfusion of the kidneys increases due to the decrease in pressure within the renal veins caused by the pumping of the blood in the downstream direction through pump 150. Conversely, after the pumping begins, this may cause the pressure within the multiple renal veins to increase relative to the pressure within the multiple renal veins immediately after the pumping begins, due to the increased blood flow into the renal veins. Typically, even after the renal perfusion increases, the pump is configured to maintain the pressure within the renal veins at a lower value compared to the pressure within the renal veins before the pumping begins. For some applications, in addition to reducing the pressure in the subject's renal veins and / or increasing perfusion of the subject's kidneys, the blood pump performs ultrafiltration on the subject's blood.

[0597] It is noteworthy that for some applications, due to the reduction in pressure within the renal vein caused by the pumping of blood in the downstream direction by pump 150, the subject's renal venous resistance is reduced according to the physiological mechanisms described, for example, by Blackfield et al., 1956, Circulation Research, an article entitled "Effect of Increased Intraluminal Pressure on Renal Vascular Resistance," which is incorporated herein by reference. More noteworthy, increasing renal perfusion by increasing blood pressure in the subject's multiple renal arteries typically does not affect the above physiological mechanisms.

[0598] As described above, typically, when blood pump 150 is used to reduce pressure within the subject's renal veins, a diuretic may be administered to the subject with an improved response by the subject due to the reduction in renal vein pressure. Thus, for some applications, a reduced diuretic dose may be administered to the subject relative to a diuretic dose that would be administered to the subject if the techniques described herein were not practiced. Alternatively, a conventional diuretic dose may be administered to the subject, but due to the reduction in renal vein pressure, the diuretic may have a better effect on the subject.

[0599] High central venous pressure results in a high level of blood pressure within the heart, which in turn results in the subject releasing atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP), both of which act as natural diuretics. Typically, when a blood pump 150 as described herein is used to reduce pressure within the subject's renal veins, it is expected that the response by the subject will be more improved than by the release of the subject's natural diuretics due to the reduced renal vein pressure. For some applications, since the subject's central venous pressure is not reduced by the use of blood pump 150, even when the subject's renal vein pressure is reduced by the use of the blood pumps described herein, it is expected that the subject will continue to release atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP). Thus, for some applications, utilizing the blood pump 150 described herein may result in a sustained release of ANP and BNP in the subject and in the effects of the aforementioned natural diuretics being greater than the effects of the diuretics when the blood pump 150 is not used.

[0600] Notably, blood pump 150 typically pumps blood in a manner that enhances the rate of blood flow through the renal veins and into the vena cava, but does not cause a substantial change in the direction of the blood flow relative to the natural direction of flow through the renal veins, or from the renal veins to the vena cava (e.g., relative to blood flow without pumping through the pump). That is, the pump pumps blood in the downstream direction through the renal veins and then directly into the portion of the vena cava adjacent to the renal veins, rather than, for example, pumping blood from the renal veins into a different portion of the subject's veins (e.g., at an upstream location within the vena cava). Also typically, the blood pump enhances blood flow through the renal veins without removing blood from the subject's venous system into a non-venous reservoir, such as an artificial lumen of a blood pump.

[0601] Typically, the shroud 154 defines a non-compressed, radially expanded configuration, in which the shroud is assumed in the absence of any forces applied to the shroud, and a radially-compressed configuration, in which the shroud is assumed when the shroud is axially elongated. Similarly, typically, the impeller 152 defines a non-compressed, radially expanded configuration, in which the impeller is assumed in the absence of any forces applied to the impeller, and a radially-compressed configuration, in which the impeller is assumed when the impeller is axially elongated.

[0602] Typically, during insertion of the hood 154 and impeller 152 into a renal vein of the subject, the hood and impeller are curled by axially stretching the hood and impeller so that the hood and impeller are radially compressed. The hood and impeller are inserted into the renal vein while being maintained in a plurality of radially compressed configurations by an insertion device 155, such as a catheter. The hood and impeller are advanced to the exterior of the distal end of the insertion device and into the renal vein. In response to being advanced to the exterior of the distal end of the insertion device, the hood and impeller automatically expand radially and contract axially.

[0603] Typically, the cover 154 is configured to keep the inner wall of the renal vein open and to separate the inner wall of the renal vein from the impeller so that the renal vein is not damaged by the impeller. Also typically, the blood pump 150 includes an engagement mechanism 156 configured to engage the impeller relative to the cover. For example, Fig. 12B As shown in FIG. 1 , which depicts a cross-sectional view of the impeller and the cover, proximal and distal bearings 250P and 250D are disposed adjacent to the proximal and distal ends of the impeller 152 and are configured to impart rotational motion to the impeller. The coupling mechanism 156 is disposed on a ring 202 disposed at the distal end of the cover (described below with reference to FIG. Fig.17 ) and a surface of the distal bearing 250P so that when the ring 202 moves distally, the ring pushes the engagement mechanism distally, which in turn pushes the distal bearing distally. The distal bearing is connected to a distal ring 164 of the impeller (hereinafter referred to as Fig.13A -D) so that the distal action of the distal bearing distally pulls the distal ring of the impeller, thereby axially lengthening the impeller.

[0604] In response to the cage becoming radially compressed and axially elongated (e.g., in response to the renal vein exerting radial pressure on the cage), the engagement mechanism thereby engages the impeller relative to the cage, the impeller axially elongates and radially compresses. FIG. 12C to FIG. 12D As shown in the transition, in response to the renal vein applying pressure P to the cover 154, the cover becomes partially radially compressed, causing the cover to elongate, for example, by moving the distal end of the cover in the direction of arrow 160. In response to the cover becoming elongated, the engagement mechanism 156 causes the impeller to elongate. The elongation of the impeller causes the impeller to be radially compressed.

[0605] The engagement mechanism 156 is typically configured so that even if a separation S1 ( Fig. 12C and 12D) is minimal at a circumferential position at which the impeller and the inner surface of the cover are maintained to have a separation between them (e.g., the impeller and the inner surface of the cover remain separated from each other) even if the cover is radially compressed. Needless to say, even if a separation S2 between the impeller and the outer surface of the cover is minimal at a circumferential position at which the impeller and the outer surface of the cover are maintained to have a separation between them (e.g., the impeller and the outer surface of the cover remain separated from each other even if the cover is radially compressed. Because the inner wall of the renal vein is supported by the outer surface of the cover, the separation S2 between the impeller and the outer surface of the cover is typically also the separation between the impeller and the inner wall of the renal vein at the position where the inner wall of the renal vein is closest to the impeller. Therefore, the engagement mechanism maintains the separation between the impeller and the inner wall of the renal vein even at the position where the inner wall of the renal vein is closest to the impeller, and even when the renal vein exerts pressure on the cover to cause the cover to compress radially.

[0606] It is noteworthy that in response to the renal vein applying pressure P to the cover 154 and causing the cover to compress radially, the separation S1 between the impeller and the inner surface of the cover, and / or the separation S between the impeller and the outer surface of the cover, may be reduced. However, even if the cover is radially compressed, the engagement mechanism maintains the impeller and the inner surface of the cover separated from each other. In this manner, the cover protects the renal vein from being damaged by the impeller even if the renal vein is compressed. It is also noted that although the inner wall of the renal vein is supported by the outer surface of the cover, the cover typically includes a plurality of struts defining a plurality of cells, and the wall of the renal vein is typically able to protrude from the plurality of cells into the cover. By maintaining the separation S1 between the impeller and the inner surface of the cover, the engagement mechanism protects the inner wall of the renal vein from being damaged by the impeller even if the inner wall of the renal vein protrudes into the cover.

[0607] When blood pump 150 is deployed in a blood vessel, such as renal vein 32, cage 154 is expanded relative to the inner wall of the blood vessel, e.g., the cage becomes rotationally fixed relative to the inner wall of the blood vessel. When the cage is rotationally fixed relative to the inner wall of the blood vessel, impeller 152 rotates to pump blood through the blood vessel. Engagement mechanism 156 is configured to engage the impeller relative to the cage so that (a) the impeller becomes radially compressed when the cage is radially compressed, (b) the impeller becomes axially elongated when the cage is axially elongated, but (c) the impeller can rotate even when the cage is rotationally fixed in place. Rotation of distal bearing 250D within the engagement mechanism is permitted by the engagement mechanism, and the engagement mechanism is configured to permit rotation of the impeller even when the cage is rotationally fixed in place.

[0608] Typically, in order to insert the cover and the impeller into the blood vessel, the cover is placed in the insertion device 155 in a crimped configuration. Typically, crimping the cover so that the cover assumes an axially elongated configuration automatically causes the impeller to assume an axially elongated configuration because the engagement mechanism imparts the longitudinal movement of the distal end of the cover to the distal end of the impeller in the manner described above.

[0609] As shown in the figure, for example, Fig. 12C -D, for some applications, pressure sensors 157 and 159 are located on the upstream and downstream sides of blood pump 150. When blood pump 150 is located in a renal vein, for example Fig. 12C -D, the pressure measured by the upstream pressure sensor 157 indicates the blood pressure upstream of the blood pump in the renal vein, and the pressure measured by the downstream pressure sensor 159 indicates the central venous pressure. For some applications, one or more sensors 161 are also provided on the blood pump (e.g., on a downstream side of the blood pump, such as Fig. 12C -D, or on an upstream side of the blood pump), and is configured to measure one or more additional parameters, such as flow through the renal vein, and / or oxygen saturation within the renal vein. Alternatively or additionally, a thermal flow sensor is used to measure flow through the renal vein. For example, a thermal flow sensor 260, as described below with reference to Figure 22Ai -Cii, can be used to measure the flow through the subject's renal vein.

[0610] Fig.12EAn end view of the impeller 152 is shown in combination with struts 204 of the cage 154 and a cross-sectional view of the renal vein 32 when the blood pump 150 is disposed within the renal vein 32 according to some applications of the present invention. The cross-sectional view of the cage and the renal vein is in a plane perpendicular to a longitudinal axis 222 of the cage at a longitudinal position at the center of the longitudinal axis of the cage. Typically, at this position, the diameter of the cage, perpendicular to the longitudinal axis of the cage, is at its maximum. Also typically, at this position, a span width of the impeller SP, perpendicular to a longitudinal axis 224 of the impeller, is also at its maximum. For some applications, the outer edge of the impeller and the inner surfaces of the struts of the cage are at their smallest separation from one another at this longitudinal position, and the outer edge of the impeller and the outer surfaces of the struts of the cage are at their smallest separation from one another at this longitudinal position.

[0611] Because the cover includes a plurality of struts 204 configured to define a plurality of cells, the cover typically allows blood to flow therethrough by allowing blood to flow through the plurality of cells defined by the cover. Fig.12E Typically, when the housing and impeller are in their radially expanded configurations within a blood vessel, such as a renal vein 32, there is a minimum separation S1 between the outer edge of the impeller and the plurality of struts 204, and a minimum separation S2 between the outer edge of the impeller and the outer surface of the plurality of struts 204 of the housing (which is also typically the minimum separation between the outer edge of the impeller and the inner wall of the blood vessel). Also typically, there are spaces between the plurality of blades of the impeller. Typically, blood can flow through the blood pump by flowing through the plurality of cells defined by the housing, and by flowing through the plurality of separations between the impeller and the housing, through the plurality of separations between the impeller and the blood vessel wall, and / or through the separations between the plurality of blades of the impeller, even if the impeller is not actively pumping blood through the blood vessel.

[0612] It is worth noting that the blood pump 150 typically does not include an occlusive member (e.g., a seal) to achieve the prevention of retrograde flow of blood through the blood pump. For some applications, when the blood pump is pumping blood in an antegrade direction, there is some retrograde flow of blood through the plurality of divisions between the impeller and the housing, through the plurality of divisions between the impeller and the vessel wall, and / or through the divisions between the plurality of blades of the impeller (e.g., within the vicinity of the center of the impeller). Alternatively or additionally, when the blood pump is pumping blood in a downstream direction, there is downstream flow of blood through the plurality of divisions between the impeller and the housing, through the plurality of divisions between the impeller and the vessel wall, and / or through the divisions between the plurality of blades of the impeller (e.g., toward the center of the impeller). Typically, regardless of whether the blood flow through the aforementioned plurality of regions is in an antegrade or retrograde direction, the blood flow through these regions reduces a likelihood of blood stagnating in these regions.

[0613] For some applications, when the impeller is in a non-compressed, radially expanded configuration (e.g. Fig.12E ), a span width SP of the impeller in a direction perpendicular to a longitudinal axis of the impeller is greater than 8 mm, less than 15 mm, and / or between 8 and 15 mm. For example, the span width SP may be greater than 8 mm, less than 12 mm, and / or between 8 and 12 mm. Alternatively, the span width SP may be greater than 10 mm, less than 15 mm, and / or between 10 mm and 15 mm.

[0614] Please refer to Fig.13A -D, which is a schematic diagram of various stages in a method of manufacturing an impeller (e.g., bladed rotor) 152 according to certain applications of the present invention. For some applications, a tube 162 (e.g., a nitinol, a stainless steel, or a plastic tube) such as Fig.13A The tube is cut (laser cut) along the dashed lines shown in the figure so that the cut tube ( Fig. 13B ) defines a structure 165 having first and second end portions, such as a plurality of rings 164 at the ends of the plurality of structures, the plurality of rings being connected by a plurality of (e.g. Fig. 13BThe first and second ends of each of the plurality of elongated elements are typically disposed at an angle α (alpha) relative to each other about the circumference of the plurality of loops. Typically, the angle α is greater than 5 degrees (e.g., greater than 50 degrees, greater than 70 degrees, or greater than 90 degrees), less than 360 degrees (e.g., less than 180 degrees, less than 150 degrees, or less than 110 degrees), and / or between 5 and 360 degrees (e.g., between 50 and 180 degrees, between 70 and 150 degrees, or between 90 and 110 degrees).

[0615] It is noted that although the plurality of elongated elements 166 are described and illustrated as a plurality of bands, the scope of the present invention includes utilizing a plurality of elongated elements having other structures, such as a plurality of elongated tubular structures, a plurality of elongated rod structures, etc., and the like shall apply accordingly.

[0616] The structure 165 is axially compressed, for example, by pushing the two rings toward each other, so that the plurality of elongated elements 166 radially expand, such as from FIG. 13B to FIG. 13C Typically, prior to axial compression of the structure (e.g., in the axially elongated configuration of the structure), a length L4 of the structure measured along the longitudinal axis of the structure is greater than 15 mm, less than 25 mm, and / or between 15 and 25 mm. Prior to axial compression of the structure (e.g., in the axially elongated configuration of the structure), a length L5 of each of the plurality of elongated elements measured along the longitudinal axis of the structure is greater than 14 mm, less than 22 mm, and / or between 14 and 22 mm. Typically, when the impeller 152 is axially elongated, the plurality of lengths of the impeller 154 and the plurality of elongated elements 166 measured along the longitudinal axis of the impeller are the same as the lengths L4 and L5, respectively. Also typically, when the impeller 152 is axially elongated, the plurality of lengths of the plurality of impeller blades 168 measured along the longitudinal axis of the impeller are the same as L5.

[0617] Typically, the structure is configured in the configuration of the axially compressed state of the structure. The structure 165 forms the support of the impeller 152. Also typically, in the axially-compressed state of the structure, each of the plurality of elongated elements 166 of the structure 165 forms a spiral shape. Each of the plurality of helical elongated elements begins at a first of the plurality of end portions (e.g., plurality of rings 164) and terminates at the second of the plurality of end portions (e.g., plurality of rings 164). The plurality of pitches of each of the plurality of helical elongated elements are typically within 20% of the other, and the plurality of helical elongated elements typically have the same pitch as the other. For some applications, the pitch of the plurality of helical elongated elements varies along the length of the plurality of helical elongated elements. The radius of the plurality of helical elongated elements is typically within 20% of the other, and the plurality of helical elongated elements typically have the same radius as the other. For some applications, the spiral defined by the two elongated elements is not symmetrical relative to the other. The longitudinal axis of each of the plurality of helical elongated elements is typically parallel to the longitudinal axis of another of the plurality of helical elongated elements, and is typically parallel to the longitudinal axis of the impeller. For some applications, each of the plurality of elongated elements defines more than one eighth of a winding of a helix, and / or less than one half of a winding of a helix, for example, between one eighth of a winding and one half of a winding of a helix.

[0618] It is noteworthy that while each of the plurality of elongated elements is described as being helical, for some applications, the plurality of elongated elements do not define a precise mathematical spiral, but rather each of the plurality of elongated elements defines a generally helical shape, wherein the elongated element spirals radially outward from a first of the plurality of end portions (e.g., a plurality of rings) when axially elongated away from the first of the plurality of end portions, and then spirals inward toward the second of the plurality of end portions when axially elongated toward the second of the plurality of end portions.

[0619] It is noted that, typically, cutting the tube 162 so that the angle α is as described above, promotes the configuration of the plurality of elongated elements 166 into the desired plurality of spiral shapes. For some applications, the tube is cut so that the angle α is not as described above, and although when a contour setting treatment is applied to the structure 165, the plurality of elongated elements 166 are configured into the desired plurality of spiral shapes by twisting the structure 165. Typically, other things being equal, when the tube 162 is cut so that the angle α is as described above, the pressure on the plurality of elongated elements 166 is reduced, promoting the configuration of the plurality of elongated elements 166 into the desired plurality of spiral shapes relative to the pressure on the plurality of elongated elements if the plurality of elongated elements were configured into the desired plurality of spiral shapes without cutting the tube to achieve the angle α as described above.

[0620] Typically, in the axially compressed configuration of the structure, a length L6 of the structure measured along the longitudinal axis of the structure is greater than 8 mm, less than 18 mm, and / or between 8 and 18 mm. Also typically, in the axially compressed configuration of the structure, a length L7 of each of the plurality of elongated elements measured along the longitudinal axis of the structure is greater than 5 mm, less than 14 mm, and / or between 5 and 14 mm. Typically, when the impeller 152 is in its uncompressed, radially expanded configuration, the lengths of the impeller 154 and the plurality of elongated elements 166 measured along the longitudinal axis of the impeller are the same as lengths L6 and L7, respectively. Also typically, when the impeller is in its uncompressed, radially expanded configuration, the lengths of the plurality of impeller blades 168 measured along the longitudinal axis of the impeller are typically the same as L7.

[0621] After axially compressing the structure 165, a material 168 (e.g., an elastic polymeric material such as silicone, polyurethane, and / or polyester) is attached to at least a portion of the structure 165, such as to the plurality of spiral elongated elements of the structure 165. Typically, the material 168 is attached to the portion of the structure 165 by dipping the structure 165 into the material 168 while the material 168 is in a liquid state. For example, the structure 165 may be dipped into liquid silicone, a silicone-based elastomer, and / or a different elastomer. Thereafter, the material is dried (e.g., by a curing and / or a polymerization process) to allow the structure 165 to be attached to the portion of the structure 165. 165. For some applications, a plurality of techniques are used to facilitate the formation of a thin film on structure 165 and / or to attach the material to the plurality of spiral elongated elements of structure 165, as described below. For some applications, during the drying of material 168, structure 165 is rotated about its longitudinal axis to facilitate the formation of a thin film of material 168 having a uniform thickness. For some applications, material 168 is attached to structure 168 in a manner other than that described above, for example, by stitching and / or electrostatically attaching an elastic polymeric material (e.g., silicone, polyurethane, and / or polyester) to the plurality of spiral elongated elements of structure 165.

[0622] The helical elongated member 166 having the material attached thereto defines the impeller blade. To form an impeller 152 having a single blade, as Fig.13D As shown in FIG. 1 , the tube 162 is cut to define a structure defining two helical elongated elements positioned between a plurality of loops 164. (Note that as shown in FIG. 1 , the tube 162 is cut to define a structure defining two helical elongated elements positioned between a plurality of loops 164.) Fig.13D The impeller in the embodiment may alternatively be described as a two-blade impeller, with each of the elongated elements connected thereto defining a blade. For example, in the end view of the impeller, as Figure 18Ai As shown in FIG. 1 , the portions of the impeller on respective sides of the ring 164 may each be considered as a blade. Although, in the context of the present application, an impeller comprising two helical elongated elements, such as Fig.13D ) For some applications, a three-blade impeller is formed by cutting the tube 162 to define a structure, defining three elongated elements between the plurality of rings 164, so that when the structure is axially compressed, the structure defines three helical elongated elements, for example, as described below with reference to Fig.16A - B. Alternatively or additionally, use an impeller with a different number of blades, for example 4-8.

[0623] Typically, the material 168 is connected to the structure 165 so that the material forms a continuous layer (e.g., a continuous film) between the plurality of elongated elements 166. More particularly, when the material is dried (e.g., by a curing or a polymerization process), and without the use of any instrument, such as a shaping mandrel configured to impart shape to the plurality of blades, the material 168 is typically configured to form one or more blades with the material supported by the plurality of spiral elongated elements 166.

[0624] like Fig.13D , the impeller blades typically form a continuous film of material 168 supported by a plurality of helical elongated elements 166, the plurality of helical elongated elements typically forming the plurality of outer edges of the blades of the impeller. Of note, the impeller typically does not include an axial support member (e.g., a shaft) along the axis of the impeller between the proximal and distal ends of the plurality of helical elongated elements to provide support to the film of material. More generally, the impeller typically does not include any support member (e.g., a shaft) between the proximal and distal ends of the plurality of helical elongated elements to provide support to the film of material 168. Thus, typically, there is no support member that disrupts the continuity of the film of material disposed between the plurality of helical elongated elements. Furthermore, rotational motion is imparted from the proximal portion (e.g., proximal ring 164) of the impeller to the distal portion (e.g., distal ring 164) of the impeller through the multiple spiral slender elements of the impeller (e.g., substantially only through the multiple spiral slender elements), and not through an axial support member (e.g., a shaft).

[0625] During the insertion of the impeller by the insertion device 155 ( Figure 12Ai ), by axially elongating structure 165, the impeller is radially compressed to straighten the plurality of helical elongated elements 166. Typically, during the axial elongation of structure 165, the film of material 168 conforms to the plurality of shape changes experienced by the plurality of helical elongated elements because no additional support member provides support to the material 168 between the proximal and distal ends of the plurality of helical elongated elements. Still typically, ceteris paribus, the lack of an axial support member (e.g., a shaft member) between the proximal and distal ends of the plurality of helical elongated elements promotes radial compression of the impeller such that the maximum diameter of the impeller when the impeller is in a maximum radially compressed configuration is smaller than that of an otherwise similar impeller but including an axial support member, e.g., the impeller is configured to be radially compressible to a smaller diameter than if the impeller included an additional support member for supporting the material between the proximal and distal ends of the plurality of helical elongated elements.

[0626] For some applications, ceteris paribus, the impeller is more resilient due to the lack of an axial support (e.g., a shaft) between the proximal and distal ends of the plurality of helical elongated elements than an impeller that is otherwise similar but includes an axial support (e.g., a shaft). During the insertion into the renal vein, the impeller and the cage are typically inserted through multiple confluences of multiple blood vessels that form multiple acute angles relative to each other and are located at relatively short distances from each other. For example, the impeller and the cage can be passed through the femoral vein, the iliac vein, into the vena cava, and then into the renal vein. The resiliency of the impeller typically facilitates the insertion of the impeller into the renal vein.

[0627] Furthermore, ceteris paribus, the absence of an axial support (e.g., a shaft) between the proximal and distal ends of the plurality of helical elongated elements facilitates axial elongation of the impeller by a predetermined length using less force than would be required to axially elongate an impeller including an axial support (e.g., a shaft) between the proximal and distal ends of the plurality of helical elongated elements by the predetermined length, since axial elongation of an impeller including an axial support typically requires axial elongation of the axial support (e.g., by axial telescoping of the support). Similarly, ceteris paribus, if a predetermined force is applied to the impeller to axially elongate the impeller, the axial elongation of the impeller is greater than the axial elongation that would be experienced by a substantially similar impeller including an axial support (e.g., a shaft) between the proximal and distal ends of the plurality of helical elongated elements.

[0628] For certain alternative applications of the present invention, the material 168 of the impeller itself is cast to facilitate the insertion of an axial support therethrough. For example, an elastomer (e.g., silicone, a silicone-based elastomer) may be used as material 168, and the elastomer may be cast to form a hollow central cavity therethrough. An axial support may be connected to the impeller by being inserted through the hollow central cavity defined by the elastomer.

[0629] Please refer to Fig.14A -B, which is a schematic diagram of a structure 165 formed from an impeller 152 having a plurality of sutures 170 tied around a portion of the structure according to some applications of the present invention. Fig.15 , which is a schematic diagram of an impeller 152 according to certain applications of the present invention.

[0630] As described above, typically, material 168 is connected to at least a portion of structure 165 when material 168 is in a liquid state and is immersed in material 168 through structure 165. For example, structure 165 can be immersed in liquid silicone. Subsequently, the material is dried (e.g., through a curing and / or a polymerization process) to form a thin film of the material supported by the plurality of spiral elongated elements of structure 165. For some applications, in order to promote the formation of a thin film of material 168 on structure 165, and / or to promote the connection of material 168 to the plurality of spiral elongated elements 166, a plurality of sutures 170 are tied around a portion of structure 165. For example, the plurality of sutures can be tied around the plurality of spiral elongated elements 166 of structure 165, such as Fig.14A , which shows a plurality of sutures 170 tied around a plurality of helical elongated elements 166 before material 168 has been attached to structure 165 .

[0631] For some applications, the sutures increase the surface area that material 168 comes into contact with when material 168 is in its liquid state. Alternatively or additionally, the surface of the sutures is rougher and / or more porous than that of elongated elements 166 (which are typically made of Nitinol). Thus, material 168 becomes connected to the sutures with a greater connection strength than the connection between material 168 and elongated elements 166. For some applications, the sutures act as intermediaries between a material from which the elongated elements are made, which typically has a relatively high stiffness (and is typically Nitinol), and material 168, which is typically an elastomer with a relatively low stiffness. The sutures thereby enhance the strength of the connection between material 168 and helical elongated elements 166 when the material dries. For some applications, the stitches prevent grooves from forming between the material 168 and the spiral elongated elements 166 during and / or after the drying of the material 168 by enhancing the strength of the connection between the material 168 and the spiral elongated elements 166. In this manner, the stitches facilitate the formation of a continuous film of the material 168 between the spiral elongated elements. Fig. 14B The impeller 152 is shown after the formation of a film of material 168 on the structure 165 , the film being supported by a plurality of helical elongated elements 166 of the structure 165 .

[0632] Alternatively or additionally, to facilitate the formation of a film of material 168 on structure 165, the edges of the end portions (e.g., loops 164) of structure 165 closest to the helical elongated elements 166 may define notches 180 therein, such as Fig.15As described above, typically, when the material 168 is in a liquid state, the material 168 is connected to at least a portion of the structure 165 by being immersed in the material 168 by the structure 165. Typically, some of the liquid material enters the plurality of indentations 180 in the plurality of end portions (e.g., the plurality of rings 164) so ​​that the contact area between the material and the structure is increased relative to the situation if the plurality of end portions do not define a plurality of indentations. Therefore, when the material is subsequently dried, the strength of the connection of the material to the structure 165 is enhanced.

[0633] Please refer to Fig.16A -B, which is a schematic diagram of an impeller 152 according to some applications of the present invention, wherein the impeller defines three blades 190. Typically, a substantially similar impeller is used as described above with reference to FIG. Fig.13A -D The impeller described in the technique produces an impeller 152 having three blades. However, instead of cutting the tube 162 ( Fig.13A ) to define two elongated elements 166 ( Fig. 13B ), the tube 162 is cut to define three elongated elements. The tube is then axially compressed so that the plurality of elongated elements form three spiral shapes, and the tube is contoured in the axially compressed configuration. Material 168 is then connected to at least a portion of structure 165. Typically, the material 168 is connected to at least a portion of structure 165 when the material 168 is in a liquid state and is immersed in the material 168 through the structure 165. For example, the structure 165 can be immersed in liquid silicone. Typically, the material is dried (e.g., by curing, and / or polymerizing) onto the plurality of spiral elongated elements so that the plurality of spiral elongated elements having the material thereon form a three-blade impeller, such as Fig.16A -B. It is worth noting that the typical Fig.16A The three-blade impeller illustrated in -B does not include an axial support member (e.g., a shaft) between the proximal and distal ends of the plurality of helical elongated elements and along the axis of the impeller for providing support to the material 168. More generally, typically, the impeller does not include a support member (e.g., a shaft) for providing support to the material 168 other than the plurality of helical elongated elements between the proximal and distal ends of the plurality of helical elongated elements. Furthermore, rotational motion is imparted from the proximal portion (e.g., proximal ring 164) of the impeller to the distal portion (e.g., distal ring 164) of the impeller by the plurality of helical elongated elements of the impeller (e.g., substantially solely by the plurality of helical elongated elements), and not by an axial support member (e.g., a shaft).

[0634] During insertion through the insertion device 155 ( Figure 12Ai), by axially elongating the impeller, the impeller is radially compressed to straighten the plurality of helical elongated elements 166. Typically, during the axial elongation of the structure 165, the material 168 conforms to the plurality of shape changes experienced by the plurality of helical elongated elements because no additional support member (e.g., a shaft) provides support to the material 168 between the proximal and distal ends of the plurality of helical elongated elements. Still typically, ceteris paribus, the lack of an axial support member (e.g., a shaft member) between the proximal and distal ends of the plurality of helical elongated elements promotes radial compression of the impeller such that the maximum diameter of the impeller when the impeller is in its maximum radially compressed configuration is smaller than that of an impeller that is otherwise similar but includes an axial support member, e.g., the impeller is configured to be radially compressible to a smaller diameter than if the impeller included an additional support member for supporting the material between the proximal and distal ends of the plurality of helical elongated elements.

[0635] For some applications, ceteris paribus, the impeller is more resilient than an impeller similar in other respects but including an axial support (e.g., a shaft) due to the lack of an axial support (e.g., a shaft) between the proximal and distal ends of the plurality of helical elongated elements. During the insertion into the renal vein, the impeller and the cover are typically inserted through multiple confluences of multiple blood vessels that form multiple acute angles relative to each other (e.g., multiple angles exceeding 70 degrees) and are located at relatively short distances from each other. For example, the impeller and the cover can be inserted into the renal vein by passing through the femoral vein, the iliac vein, into the vena cava, and then into the renal vein. The resiliency of the impeller typically facilitates the insertion of the impeller into the renal vein.

[0636] Furthermore, as described above, the absence of an axial support member (e.g., a shaft member) between the proximal and distal ends of the plurality of helical elongated elements facilitates axial elongation of the impeller by a predetermined length using less force than would be required to axially elongate an impeller including an axial support member (e.g., a shaft member) between the proximal and distal ends of the plurality of helical elongated elements. Similarly, other things being equal, if a predetermined force is applied to the impeller to axially elongate the impeller, the axial elongation of the impeller is greater than the axial elongation that would be experienced by a substantially similar impeller including an axial support member (e.g., a shaft member) between the proximal and distal ends of the plurality of helical elongated elements.

[0637] For certain alternative applications of the present invention, the material 168 of the impeller itself is cast to facilitate the insertion of an axial support therethrough. For example, an elastomer (e.g., silicone, a silicone-based elastomer) may be used as material 168, and the elastomer may be cast to form a hollow central cavity therethrough. An axial support may be connected to the impeller via the hollow central cavity defined through the elastomer.

[0638] Please refer to Fig.17 , which is a schematic diagram of a protective cover 154 of a blood pump 150 according to some applications of the present invention. Typically, the cover includes proximal and distal rings 202. Between the proximal and distal rings, the cover includes a plurality of struts 204 configured to define a plurality of cells. For some applications, in a non-compressed, radially expanded configuration of the cover (e.g., without any external force applied to the cover), the cover between the proximal and distal rings defines a generally spherical or ovoid shape, such as Fig.17 As shown in FIG. 156 ( Fig. 12B ) typically with respect to the cover 154 through a plurality of rings 164 of the impeller ( Fig.13A -D), the plurality of rings 202 of the cover, and the distal bearing 250D ( Fig. 12B ) to engage the impeller.

[0639] For some applications, when the cover 154 is in its radially expanded configuration, a length L8 of the cover, measured along the longitudinal axis of the cover and including the rings 202 of the cover, is greater than 17 mm, less than 26 mm, and / or between 17 and 26 mm. A length L9 of the cover, measured along the longitudinal axis of the cover and excluding the rings 202 of the cover, is greater than 12 mm, less than 21 mm, and / or between 12 and 21 mm. For some applications, when the cover is axially elongated and radially compressed by being crimped (configuration not shown), the length of the cover, measured along the longitudinal axis of the cover and including the rings 202 of the cover, is greater than 22 mm, less than 35 mm, and / or between 22 and 35 mm. Typically, for such applications, when the cover is axially elongated by being crimped (configuration not shown), the length of the cover measured along the longitudinal axis of the cover and excluding the plurality of rings 202 of the cover is greater than 18 mm, less than 30 mm, and / or between 18 and 30 mm. For some applications, the cover 154, in its radially expanded configuration, has a diameter D7 of greater than 8 mm, less than 20 mm, and / or between 8 and 20 mm. For example, the diameter D7 may be greater than 8 mm, less than 15 mm, and / or between 8 mm and 15 mm. Alternatively, the diameter D7 may be greater than 13 mm, less than 19 mm, and / or between 13 mm and 19 mm.

[0640] The cage is typically inserted into a blood vessel (e.g., into the renal vein) while in a crimped configuration thereof (e.g., when the cage is axially elongated and radially compressed relative to the non-compressed configuration of the cage). As described above, during insertion of the impeller into the blood vessel, the impeller is radially compressed by axially elongating structure 165 to straighten the plurality of helical elongated elements 166. Typically, the film of material 168 conforms to the plurality of shape changes experienced by the plurality of helical elongated elements during the elongation of the impeller. Also typically, during insertion of the blood pump into the blood vessel, the impeller 152 is already disposed within the cage. Thus, during insertion of the blood pump into the blood vessel, the impeller 150 is disposed within the cage when the cage is in a crimped configuration thereof, and when the impeller is in an axially elongated configuration thereof, wherein the plurality of helical elongated elements of the impeller are straightened. Typically, in response to release from the insertion device positioned within the blood vessel, the cover automatically assumes the non-compressed, radially expanded configuration of the cover. Similarly, in response to release of the cover and the impeller from the insertion device, the impeller typically automatically expands radially within the cover to assume one of the non-compressed, radially expanded configurations.

[0641] Please refer to Figure 18Ai-18Aii , which is a schematic diagram of an example of a structure 165 forming the support of the impeller 152 according to some applications of the present invention.

[0642] As indicated by the inner dashed circle 194, it is Figure 18Ai-18Aii The two have the same size, shown in Figure 18Ai and 18Bi The plurality of impellers depicted in each of the FIGS. rotate to encompass a circular area of ​​equal size. Thus, as indicated by the outer dashed circle 196, the Figure 18Ai-18Aii The two are the same size, shown in Figure 18Ai and 18Bi The plurality of impellers in each of the plurality of impellers are adapted to be placed in a blood vessel having a predetermined cross-sectional area to have a separation between the inner wall of the blood vessel and the impellers, as described above. (The outer dotted circle represents the cross-section of the inner wall of the blood vessel into which the impellers are placed). Figure 18Bi-18Biii The impeller structure 165 is configured so that, compared to the impeller structure shown in Figure 18Ai-18Aiii The plurality of impeller blades formed by the structure 165 in the embodiment of the present invention span a large cross-sectional area. In other words, when viewed from one end of the impeller (e.g. Figure 18Ai and 18Bi ), and then plotted in Figure 18Bi-18Biii The plurality of blades of the impeller support in the embodiment of the present invention span a transverse area (e.g., an area transverse to the axis of the impeller) that is greater than that of the impeller support in the embodiment of the present invention. Figure 18Ai-18Aiii Similarly, when viewed from one end of the impeller (e.g. Figure 18Ai and 18Bi ), and then plotted in Figure 18Bi-18Biii Each of the plurality of blades of the impeller support is defined by a surround smaller than Figure 18Ai-18Aiii Each of the plurality of blades of the impeller depicted in FIG. 8 defines an angle θ (theta) with respect to the longitudinal axis of the impeller.

[0643] Typically, ceteris paribus, for an impeller placed in a blood vessel of a predetermined diameter, the greater the motive force of the blood passing through the vessel at a predetermined rotational rate of the impeller (and, therefore, the greater the efficiency of the impeller), the greater the area across which the plurality of blades of the impeller span the vessel (e.g., the area of ​​the blood is transverse to the longitudinal axis of the vessel). Figure 18Ai -iii and 18Bi-iii, the efficiency of the impeller is typically greater, the greater the angle θ is defined by the impeller blades on each side of the longitudinal axis of the impeller. Figure 18Ai -iii and 18Bi-iii, other things remaining unchanged, are shown in Figure 18Bi The typical ratio of the impeller in -iii is shown in Figure 18Ai However, as described in more detail below, when the impellers are axially elongated, then, other things being equal, an impeller defining blades spanning a larger cross-sectional area will typically be longer than an impeller defining blades spanning a smaller cross-sectional area.

[0644] It is noteworthy that for certain applications, such as a single blade impeller used herein, and the value of θ (e.g., the angle defined by the blades of the impeller on each side of the longitudinal axis of the impeller) is greater than 5 degrees (e.g., greater than 50 degrees, greater than 70 degrees, or greater than 90 degrees), less than 360 degrees (e.g., less than 180 degrees, less than 150 degrees, or less than 110 degrees), and / or between 5 and 360 degrees (e.g., between 50 and 180 degrees, between 70 and 150 degrees, or between 90 and 110 degrees).

[0645] During insertion of the blood pump 150 into the blood vessel, the impeller 152 is typically disposed within the housing when the housing is in one of its axially elongated, curled configurations and when the impeller is in one of its axially elongated, curled configurations. Thus, the length defined by the impeller when the impeller is in its axially elongated, curled configuration is typically less than the length of the housing when the housing is in its axially elongated, curled configuration. Conversely, the size of the housing is limited because the diameter of the housing in its radially expanded configuration is limited based on the size of the blood vessel into which the blood pump is to be placed.

[0646] For some applications, the cover is configured to include a plurality of struts 204 having a contour setting to include a plurality of undulating portions 210, such as Fig. 18C , as shown in (which is described in more detail below). Typically, when the shroud is in its radially expanded configuration, the undulation of the undulating portions of the struts of the shroud is greater than the undulation of the undulating portions of the struts when the shroud is in its axially elongated configuration. For some applications, a shroud having a predetermined diameter and / or outer profile in its radially expanded configuration may be elongated to define a greater length by including struts having undulations as compared to a shroud having a similar diameter and / or outer profile that does not include struts having undulations. In this manner, the shroud (a) may accommodate an impeller that is longer in its axially elongated configuration (and, therefore, defines a larger traverse area in its radially expanded configuration) as compared to a shroud that does not include struts having undulations but (b) the diameter and / or outer profile of the shroud in its radially expanded configuration is substantially similar to the shroud that does not include struts having undulations.

[0647] as follows Figure 18Ai-18C There is a more detailed description.

[0648] As mentioned above, the Figure 18Bi-18Biii The impeller structure 165 is configured so that, compared to the impeller structure shown in Figure 18Ai-18Aiii The multiple impeller blades formed by the structure 165 in the embodiment of the present invention, the multiple blades of the impeller span a larger cross-over area. Figure 18Aii and 18Bii side views of the two examples of the structure 165 are shown, and Figure 18Aiii and 18BiiiThe examples of the structure 165 are shown in the axially elongated configurations of the structures, wherein the helical elongated elements of the structures are flattened. As described above, during insertion of the blood pump 150 into the blood vessel, the impeller is typically in the axially elongated configuration, such as Figure 18Aiii and 18Biii In order to make the plurality of impeller blades span a larger traverse area (such as Figure 18Bi ), compared to having a smaller traversal area (as shown in Figure 18Ai ) of an impeller having multiple blades, the lengths of the multiple elongated elements 166 are typically longer. Thus, when the multiple impellers are in their multiple axially elongated configurations, the multiple lengths of the multiple elongated elements 166 are typically longer. Figure 18Bi-18Biii The length LB of the impeller in is greater than that shown in Figure 18Ai-18Aiii The length LA of the impeller.

[0649] Please refer to Fig. 18C , which is a schematic diagram of a cover 154 according to some applications of the present invention, the cover including at least some of the struts 204 having a plurality of undulating portions 210 thereof. Fig.18D , which is a schematic diagram of side views of radially expanding shields according to certain applications of the present invention, one of which includes struts 204 with undulating portions 210 thereof (the left shield), and another of which does not include struts with undulating portions thereof (the middle shield). Fig.18D The right side of the cover including the plurality of pillars with the plurality of undulating portions covers the cover not including the plurality of pillars with the plurality of undulating portions, and has the plurality of pillars including the plurality of undulating portions drawn with a plurality of solid lines, and the plurality of corresponding pillars of the second cover not including the plurality of undulating portions drawn with a plurality of dotted lines. Fig.18D The inclusion of the plurality of undulating portions within some of the plurality of struts does not change the outer profile of the cover when viewed in the portion of the cover. However, the plurality of undulating portions of the plurality of struts add length to the plurality of struts, such that, other things being equal, the total axially elongated length of the stent including the plurality of struts having the plurality of undulating portions is greater than the total axially elongated length of the stent not including the plurality of struts having the plurality of undulating portions.

[0650] As described above, typically, the length of the impeller when the impeller is in its axially elongated, curled configuration is less than the length of the cover when the cover is in its axially elongated, curled configuration, so that the curled cover can accommodate the axially elongated impeller. Conversely, the multiple sizes of the cover are limited because the diameter of the cover in the radially expanded configuration of the cover is limited based on the size of the blood vessel into which the blood pump is to be placed. For a blood vessel having a diameter such as Fig.17 Of the multiple cages of the multiple configurations depicted in , a cage having a longer crimped length then typically expands to have a larger maximum diameter within the vessel, which is undesirable.

[0651] For some applications, in order to increase the axially extended length of the cage without increasing the diameter of the cage when the cage is in the radial expansion state, a Fig. 18C A cover is shown in FIG. Fig. 18C The mask in the embodiment of the present invention comprises certain struts, including a plurality of undulating portions 210. During crimping of the mask, the plurality of undulating portions are configured to become at least partially flattened, thereby adding to the crimped length of the mask relative to if the plurality of portions 210 were not undulated. When the mask is radially expanded within the vessel, the plurality of undulating portions become undulated, but do not add to the diameter of the mask or otherwise change the outer profile of the mask relative to if the plurality of undulating portions were straight. Thus, in general, when the mask is in one of its crimped configurations, the additional length provided to the mask by the plurality of undulating portions does not add to the diameter of the mask while the mask is expanded within the vessel.

[0652] As described above, during insertion of the mask into the renal vein, the plurality of undulating portions of the plurality of struts of the mask at least partially flatten. When the mask assumes its radially expanded configuration within the renal vein, the degree of undulation of the plurality of undulating portions of the plurality of struts of the mask increases. For some applications, for each of the plurality of struts defining the plurality of undulating portions, the struts are configured such that:

[0653] (a) the shortest distance from a first longitudinal end of the strut to a second longitudinal end of the strut when the cover is in its axially elongated configuration (e.g., when the undulating portion is at least partially flattened),

[0654] and

[0655] (b) the shortest distance from the first longitudinal end of the strut to the second longitudinal end of the strut when the shield is in its radially expanded configuration (e.g., when the undulating portion is at the level of undulation at which the strut is contoured),

[0656] A ratio of the above two is greater than 1.05:1, such as greater than 1.15:1 or greater than 1.2:1.

[0657] For some applications, the ratio is less than 1.4:1, for example, the ratio may be between 1.05:1 and 1.4:1, between 1.15:1 and 1.4:1, or between 1.2:1 and 1.4:1.

[0658] Please refer to Fig.19A -B, which is a schematic diagram of an impeller guard 154 according to some applications of the present invention, wherein the guard is configured to define a central portion having a generally cylindrical shape without any force applied to the guard. The outer surface of the guard at the generally cylindrical portion of the guard is parallel to the longitudinal axis 222 of the guard. Fig.19A The cover itself is shown, and Fig.19B The cage is shown positioned within a blood vessel, such as a renal vein 32 .

[0659] Fig.19B The cover 154 is shown with radial expansion within the blood vessel (e.g., within the renal vein 32) to anchor the cover to the blood vessel. As described above, the blood pump 150 ( Figure 12Ai ) is configured to pump blood axially through the blood vessel. Typically, in order to achieve efficient pumping of blood through the blood vessel, it is desirable that a longitudinal axis 224 of the impeller is aligned with a longitudinal axis 226 of the blood vessel. Also typically, the plurality of rings 164 of the impeller 152 are aligned with the plurality of rings 202 of the cover 154 so that the longitudinal axes of the impeller and the cover are aligned with each other. For example, Fig. 12B As shown in , the longitudinal axes of the impeller and the cover can be aligned with each other by: (a) placing the multiple proximal rings of the impeller and the cover around a first support member (e.g., a proximal bearing 250P) so that the multiple proximal rings of the impeller and the cover are aligned with each other; and (b) placing the multiple distal rings of the impeller and the cover around a second support member (e.g., a distal bearing 250D) so that the multiple distal rings of the impeller and the cover are aligned with each other.

[0660] like Fig.19BAs shown in , the generally cylindrical central portion 220 of the cover 154 becomes anchored to the blood vessel so that the longitudinal axis of the cover is aligned with the longitudinal axis of the blood vessel. Because the longitudinal axes of the impeller and the cover are aligned with each other, the generally cylindrical central portion 220 of the cover allows the impeller to be positioned within the blood vessel so that the longitudinal axis of the impeller is aligned with the longitudinal axis of the blood vessel.

[0661] As used in this application, including in the claims, a "longitudinal axis" of a structure is the set of all centroids of cross-sectional portions of the structure along the structure. The cross-sectional portions are thus locally perpendicular to the longitudinal axis along the direction of the structure. (If the structure is circular in cross-section, the centroids correspond to the centers of the circular cross-sectional portions.)

[0662] Please refer to Fig. 20 , which is a schematic diagram of an impeller guard 154 configured to be placed within a blood vessel (e.g., renal vein 32) to increase the diameter of a portion of the blood vessel relative to the diameter of the blood vessel without the impeller guard. Fig. 20 As shown in , for some applications, the cover is configured to expand a blood vessel having a diameter D6 in the absence of the cover so that a portion of the blood vessel has a diameter greater than D6. For example, the cover can widen the blood vessel so that when the blood vessel is widened, the diameter of the blood vessel is greater than 105 percent of the diameter D6, such as greater than 110 percent, or greater than 115 percent. For some applications, the cover widens the blood vessel so that when the blood vessel is widened, the diameter of the blood vessel is less than 125 percent of the diameter D6. For example, the widened diameter can be 105-125 percent, 110-125 percent, and / or 115-125 percent of the diameter D6. For some applications, the impeller 152 of the blood pump 150 is configured to span a diameter that is at least the same as the diameter D6 of the blood vessel. Typically, all other factors being equal, the more the impeller spans the diameter, the greater the flow rate at which the impeller can pump blood through the blood vessel.

[0663] Please refer to Fig.21A , which is a schematic diagram of a plurality of blood pumps 150 based on an impeller according to some applications of the present invention inserted into the left and right renal veins 32 of a subject through the femoral vein 230 of the subject. It is noted that the details of the blood pumps 150 are not shown in FIG. Fig.21A, but the pumps are substantially as described above. Typically, the blood pumps are inserted into the left and right renal veins via respective catheters 155, and both catheters are inserted via the femoral vein. Alternatively (not shown), the blood pumps are inserted via a single catheter passed from a femoral access point to the subject's vena cava.

[0664] Typically, the impellers of the blood pump 150 are connected to rotors 232 that impart rotational motion to the impellers. Depending on the application, the applications are located outside the subject's body (as shown) or placed inside the subject's body (not shown). Typically, a control unit 234 and a user interface 236 are located outside the subject's body. Also typically, the control unit receives inputs from pressure sensors 157 and 159, which are located on the upstream and downstream sides of the blood pumps, as described above with reference to Fig. 12C -D. When the blood pump 150 is located in a renal vein (e.g., Fig.21A ), the pressure measured by upstream pressure sensor 157 indicates the blood pressure upstream of the blood pump, in the renal vein, and the pressure measured by downstream pressure sensor 159 indicates the central venous pressure. For some applications, the control unit receives an input from an additional sensor 161 (e.g., a flow sensor and / or an oxygen saturation sensor), which is located on the blood pump (e.g., at a downstream of the blood pump, such as Figure 12Ai Alternatively or additionally, the control unit receives an input from a thermal flow sensor, such as the following reference Figure 22Ai - Thermal flow sensor 260 of Cii.

[0665] For some applications, in response to one or more of the above inputs, control unit 234 controls the rotation of impeller 152 by controlling motor 232. Typically, user interface 236 displays the subject's current renal venous pressure and central venous pressure based on the multiple pressures measured by sensors 157 and 159. Typically, a user (e.g., a medical professional) enters a target value for the subject's renal venous pressure through the user interface based on the multiple current values ​​of the subject's renal venous pressure and central venous pressure. In response to the above, control unit 234 controls the speed of the rotation of the impeller so that the impeller draws through the renal vein and toward the vena cava at a flow rate that reduces the renal venous pressure toward the target level, as indicated by the user. For some applications, in response to a message received from sensor 159 indicating that the central venous pressure is downstream of the target renal venous pressure, the control unit stops the impeller rotation. Generally, in response to multiple inputs from pressure sensors 157 and 159, the control unit typically controls the speed of the rotation of the impeller. For some applications, in response to the additional sensor 161 and / or the heat flow sensor 260 (such as Figure 22Ai-22Cii With an input from a sensor (shown in ), the control unit typically controls the speed of the rotation of the impeller.

[0666] It is noteworthy that a "control unit" described in this application, in the description and the claims, includes any type of processor (e.g., a computer processor) configured to perform the multiple actions described herein. A "user interface" includes any type of user interface configured to receive multiple inputs from a user and / or provide multiple outputs to the user. For example, the user interface may include one or more input devices (e.g., a keyboard, a mouse, a trackball, a touch screen display, a touchpad, a voice interface, a smartphone, a tablet computer, and / or other types of input devices known in the art), and / or one or more output devices (e.g., a display, an audio output device, a smartphone, a tablet computer, and / or other types of output devices known in the art).

[0667] Please refer to Fig. 21B , which is a schematic diagram of a plurality of impeller-based blood pumps 150 inserted into the left and right renal veins 32 of a subject through the subject's subclavian vein 240 according to some applications of the present invention. It is worth noting that the details of the blood pumps 150 are not shown in FIG. Fig. 21BTypically, the blood pumps are inserted into the left and right renal veins via separate catheters, and both catheters are inserted through the femoral vein. Alternatively (not shown), the blood pumps are inserted via a single catheter that is then passed from a subclavian access point to the subject's vena cava. In addition to inserting the renal veins via a different vein, such as Fig. 21B The plurality of blood pumps 150 shown in FIG. 1 are substantially the same as those in FIG. Fig.21A A plurality of blood pumps 150 are shown in FIG.

[0668] Please refer to Figure 22Ai -Cii, which is a schematic diagram of a thermal flow sensor 260 used in conjunction with a blood pump 150 according to some applications of the present invention. The thermal flow sensor typically includes an upstream temperature sensor 262, a downstream temperature sensor 264, and a heating element 266 disposed between the upstream and downstream temperature sensors. Figure 22Ai According to the multiple flow arrows shown in the enlarged view of the thermal flow sensor shown in , blood flows over the upstream temperature sensor to the heating element. When the blood flows over the heating element, the heating element heats the blood. The heated blood then flows to the downstream temperature sensor. The extent to which the blood that has been heated by the heating element flows over the downstream temperature sensor is based on the flow rate of the blood. Therefore, the thermal flow sensor measures a change in the temperature of the blood between the upstream and downstream temperature sensors, and determines the flow of the blood in response to the above situation.

[0669] As reference Fig.21A -B, for some applications, the control unit controls the speed of the rotation of the impeller in response to an input from a thermal flow sensor 260. Typically, the component of the blood flow through the renal vein in the axial direction is of interest, such as the axial component of the blood flow parallel to the local longitudinal axis of the renal vein, because this determines the blood flow rate away from the subject's kidney. However, due to the rotation of the impeller, the blood flow downstream of the impeller typically includes multiple components other than the axial component (e.g., rotational and multiple radial components). For some applications, the thermal flow sensor is disposed in a housing 268 and is configured to direct blood flow through the housing generally in the axial direction, and relative to blood flow through the renal vein outside the housing, so that multiple components that are not the axial component of the blood flow (e.g., rotational and multiple radial components) are reduced.

[0670] Please refer to Figure 22Ai and 22Aii, which are schematic diagrams of a cross-sectional view and a top view, respectively, of a thermal flow sensor 260 and a housing 268 according to certain applications of the present invention. Typically, the impeller 152 and the cover 154 of the blood pump 150 are disposed at the rear end of an elongated element 270 (e.g., a tube) of the pump. For certain applications, the elongated element 270 defines a notch, and the thermal flow sensor is received within the notch, the outer surface of the elongated element 170 defining the notch thus comprising the housing 168. The upstream temperature sensor 262, the heating element 266, and the downstream temperature sensor 264 are typically disposed in sequence along the length of the notch, as shown. Typically, a ratio of a length LI of the notch to a width WI of the notch is greater than 4:1; and / or less than 8:1, such as between 4:1 and 8:1. The ratio of the length LI to the width WI is typically such that blood flow through the aperture is generally in the direction parallel to the local longitudinal axis of the renal vein (and parallel to the local longitudinal axis of the elongated element) and such that components other than the axial components of the blood flow (e.g., rotational and radial components) are reduced relative to blood flow through the renal vein outside the housing. Because the thermal sensor is housed within the aperture, the thermal flow sensor measures the blood flow in the direction generally parallel to the local longitudinal axis of the renal vein (and parallel to the local longitudinal axis of the elongated element).

[0671] For some applications (not shown), a single thermistor is used to measure flow, and the single thermistor is placed within a housing, typically such that blood flow through the housing is generally in the direction parallel to the local longitudinal axis of the renal vein (and parallel to the local longitudinal axis of the elongate element), and such that components other than the axial components of the blood flow (e.g., rotational and multiple radial components) are reduced relative to blood flow through the renal vein outside the housing, for example using a relative comparison. Fig.21A i-22Cii describes a plurality of techniques. For such applications, a ratio of a length of the housing to a width of the housing is typically greater than 1:1, such as greater than 4:1, and / or less than 8:1, such as between 4:1 and 8:1. For such applications, when Figure 22Ci -ii is used, wherein the ratio of the length of the shell to the height of the shell is typically greater than 1:1, such as greater than 4:1, and / or less than 8:1, such as between 4:1 and 8:1.

[0672] Please refer to Figure 22Bi and 22Bii , which are schematic diagrams of a cross-sectional view and a top view of a thermal flow sensor 260 and a housing 280 according to certain applications of the present invention. Figure 22Bi-22BiiThe housing 268 shown is generally similar to that in Figure 22Ai-22Aii Except for the Figure 22Bi -ii, the thermal flow sensor is covered by a cover except for the space within the notch in the elongated element 5. In other respects, the thermal sensor and housing are substantially as described with reference to Figure 22Ai-22Aii described.

[0673] Please refer to Figure 22Ci-22Cii , which is a schematic diagram of various cross-sectional views of thermal flow sensor 260 and housing 268 according to some applications of the present invention. For some applications, housing 268 containing thermal sensor 260 includes a housing, such as a tube, connected to the outer surface of elongated member 270 of blood pump 150. Typically, the housing is compressible so that the housing can be compressed during insertion of the blood pump into the blood vessel of the subject via insertion device 155.

[0674] The upstream temperature sensor 262, the heating element 266, and the downstream elongation sensor 264 are typically disposed sequentially along the length of the housing, within the housing, as shown. Typically, a ratio of a length LH of the housing to a width WH of the housing is greater than 4:1; and / or less than 8:1, such as between 4:1 and 8:1. Still typically, a ratio of a length LH of the housing to a height HH of the housing is greater than 4:1; and / or less than 8:1, such as between 4:1 and 8:1. The ratios of length LH to width WH, and length LH to height HH are typically such that blood flow through the housing is generally in the direction parallel to the local longitudinal axis of the renal vein (and parallel to the local longitudinal axis of the elongated element), and such that components other than the axial component of the blood flow (e.g., rotational and radial components) are reduced relative to blood flow through the renal vein outside the housing. Because the thermal sensor is housed within the notch, the thermal flow sensor measures the blood flow in the direction generally parallel to the local longitudinal axis of the renal vein (and parallel to the local longitudinal axis of the elongate element).

[0675] It is worth mentioning that in Figure 22Cii In the embodiment of the present invention, the interior of the elongated member 270 is shaded for explanation purposes. However, typically, the elongated member 270 houses a plurality of control mechanisms for controlling the movement of the impeller 152 and the cage 154.

[0676] Experimental results:

[0677] Please refer to Fig.23, which is a graph illustrating the results of experiments performed on a healthy pig using an impeller-based blood pump 150 according to certain applications of the present invention. Throughout the experiment, the pig's left renal vein pressure was directly measured using a pressure sensor located in the pig's left renal vein. In addition, the pig's right renal vein pressure was measured using a pressure sensor in the vena cava at the level of the renal vein. Baseline levels of left renal blood flow, and urine output from the left and right kidneys were also measured, and the aforementioned parameters were measured again at certain time points during the experiment.

[0678] A balloon is inflated within the porcine vena cava at the confluences between the vena cava and both the left and right renal veins. The balloon is inflated to increase the blood pressure within the porcine vena cava downstream of the renal veins by partially obstructing blood flow through the vena cava downstream of the renal veins. While the balloon is inflated within the porcine vena cava, an impeller-based blood pump, such as described herein, is activated to pump blood through the porcine left renal vein, although no assistance is provided to the blood flow through the porcine right renal vein. While the balloon remains in an inflated state, the blood pump in the left renal vein is temporarily shut off for a period of time before being reopened. Subsequently, the balloon within the vena cava is deflated, and the blood pump is shut off.

[0679] exist Fig.23The upper graph in FIG. 1 indicates the left renal vein pressure, indicated by the solid curve, and the right renal vein pressure, indicated by the phantom curve, as measured during the experiment. It is noteworthy that in order to more clearly illustrate the left and right renal vein pressure measurements, where the left and right renal vein pressure measurements are the same (e.g., approximately between 12:35 and 13:28), the two curves have been slightly separated. In addition, multiple small changes in venous pressure have been ignored. As shown, initially, during the baseline period, the left and right renal vein pressures were similar to each other, approximately 8 mmHg. Subsequently, at 13:28, the balloon was inflated, and the impeller-based blood pump was activated in the left renal vein. As a result of the balloon being inflated, the pressure in the vena cava rose, and therefore the right renal vein pressure rose to approximately 22 mmHg. Although the pressure in the vena cava increased significantly, the impeller-based blood pump was activated in the left renal vein. The pressure in the vein rose, and the left renal pressure did not increase due to the pumping of blood through the renal vein. At approximately 14:10, the blood pump in the left renal vein was turned off, and as a result, the left renal pressure rose to the level of the venous pressure in the vena cava. Subsequently, at approximately 14:40, the pump was turned on again, and as a result, the pressure in the left renal vein dropped. Subsequently, at 15:24, the balloon was deflated and the renal pressure in the vena cava, and therefore the right renal vein pressure, dropped. These results indicate that an impeller-based blood pump as described herein can effectively reduce renal venous pressure even if a subject has elevated central venous pressure.

[0680] Fig.23 The middle graph of depicts the renal blood flow measured in the left renal vein. As shown, the baseline value of the left renal blood flow is approximately 360 mm / min. When the balloon has been inflated in the vena cava and the blood pump is operated in the left renal vein, the renal blood flow is measured again. As shown, the left renal blood flow has risen to approximately 440 ml / min due to the extraction of blood by the blood pump. Subsequently, when the balloon is inflated in the vena cava, and when the blood pump has been turned off, the left renal blood flow is measured, and the renal blood flow has dropped to approximately 380 ml / min. Subsequently, when the blood pump has been turned back on, the left renal blood flow is measured again, and the left renal blood flow has risen again to approximately 340 ml / min. These results indicate that an impeller-based blood pump as described herein can effectively increase renal blood flow even if a subject's central venous pressure is elevated.

[0681] It is noted that for explanation purposes, the changes in renal blood flow between one data point and the next are plotted on the graph as having occurred at a constant rate. However, the inventors speculate that the changes in renal blood flow are largely due to the blood pump being turned on or off in the left renal vein and / or due to the inflation of the balloon in the vena cava, such that most of the changes in renal blood flow have already occurred based on the occurrence of the above events.

[0682] Fig.23 The lower graph of shows urine volume measured at the left kidney (indicated by the solid curve) and the right kidney (indicated by the phantom curve) of the pigs at certain times during the experiment. It is noteworthy that, in general, the blood flow rate through the kidneys is known to have an effect on the urine volume rate. As shown, urine production from the left and right kidneys was approximately 21 mm per 10 minutes when measured during the baseline period. Subsequently, urine volume was measured at approximately 14:00 when the balloon in the vena cava was inflated and when the blood pump was operated in the left renal vein. As shown, urine volume from the left kidney increased when urine volume production from the right kidney had decreased. These results indicate that even when central venous pressure increases, which may result in decreased urine volume (as indicated by the urine volume from the right kidney), increasing renal blood flow by pumping blood using a blood pump (as implemented in the left renal vein) can increase urine volume.

[0683] Then, at approximately 14:35, while the balloon was still inflated in the vena cava, but while the blood pump was turned off, urine output from the left and right kidneys was measured. At this point, urine production at the right kidney had continued to decline, while urine output from the left kidney had also declined. Then, after the blood pump had been turned on again, and while the balloon of the vena cava was still inflated, urine output from the right kidney had stabilized at approximately 14 mm per 10 minutes, while urine output from the right kidney rose to approximately 48 mm per 10 minutes.

[0684] Note that for explanation purposes, the changes in urine production between one data point and the next are plotted on the graph as having occurred at a constant rate. However, the inventors speculate that the changes in urine production are generally due to the blood pump being turned on or off in the left renal vein and / or due to the inflation of the balloon in the vena cava, such that most of the changes in urine production have already occurred based on the occurrence of such events.

[0685] In yet another experiment, an impeller-based blood pump as described herein was used to pump blood through the renal veins of a different pig over a continuous period of three hours. During this time period, there was no incidence of thrombosis or abnormal levels of hemolysis. This indicates that an impeller-based blood pump as described herein can be used to increase blood flow through a subject's kidneys, thereby reducing pressure in the renal veins, without causing a risk of thrombosis and / or abnormal levels of hemolysis. It is worth noting that during the aforementioned experiment, an anticoagulant was administered to the pigs. However, because in a typical procedure performed on a human subject using an impeller-based blood pump as described herein, the subject is administered an anticoagulant, it remains the case that the results indicate that an impeller-based blood pump as described herein can be used to increase blood flow through a subject's renal veins, thereby reducing pressure in the renal veins, without causing a risk of hemolysis and / or thrombosis.

[0686] In general, in the experiments described above, and in additional experiments performed by the inventors of the present application using blood pump 150 in pigs, the following observations were made:

[0687] 1. The blood pump 150 is smoothly deployed and retracted in one minute or less.

[0688] 2. An effective and continuous reduction in renal venous pressure from approximately 20 mmHg to a predetermined target value of 8 mmHg within a minimal margin of change.

[0689] 3. Increased venous pressure in the renal vein decreased urine output, creatinine clearance, and sodium excretion rate in untreated kidneys, but not in kidneys treated with blood pump 150. These results indicate that use of blood pump 150 has a beneficial effect on glomerular and tubular function.

[0690] 4. Use of blood pump 150 preserves and restores renal blood flow, urine volume, and sodium excretion rate even when venous pressure in the vena cava is elevated

[0691] 5. Blood pump 150 successfully operated in a closed loop mode with the pressure in the renal vein remaining constant for more than 3 hours.

[0692] 6. No thrombus was observed in any part of the blood pump or the catheter.

[0693] 7 No clinically significant hemolysis was observed when the pump was operated for more than 3 hours.

[0694] It is noted that while some of the pumps and / or occlusion members described herein are depicted as being inserted into a predetermined one of the subject's renal veins, the scope of the present invention includes inserting the pumps and occlusion members into a left or right renal vein, or both renal veins of a subject. Furthermore, the scope of the present invention includes inserting the pumps and occlusion members into more than two renal veins of a subject having more than two renal veins, as in some humans.

[0695] It is worth noting that although some of the pumps and / or occlusion members described herein are depicted as being inserted into the renal veins of the subject, the scope of the present invention includes inserting the pumps and occlusion members into other blood vessels of a subject, as described above. For example, in order to reduce venous pressure in the veins and / or reduce pressure in an organ that draws blood from the veins (e.g., to reduce liver congestion), the reversing valve 40 ( Figure 5A -D and 6A-F) can be placed in a subject's hepatic vein, intestinal vein, or adrenal vein.

[0696] Alternatively or additionally, in order to reduce venous pressure in the vein and / or to reduce pressure in an organ that draws blood from the vein (e.g., to reduce liver congestion), blood pump 90 ( Fig. 8A -B and 10A-D) can be placed in a subject's hepatic vein, intestinal vein, or adrenal vein. Alternatively, a blood pump can be placed in a fluid-filled cavity inside the brain in order to reduce intracranial pressure by draining cerebrospinal fluid from the cavity. Alternatively or additionally, blood pump 90 can function as a left ventricular assist device by being placed in the subject's aorta and pumping blood away from the left ventricle. Still alternatively or additionally, blood pump 90 can be placed in the urethra to maintain open the subject's prostate and drain the subject's bladder.

[0697] In general, the sleeve 110 ( Fig. 10A -C) can be used to separate into a separate compartment blood from blood flow in a main vein, blood in multiple tributary veins supplying the main vein, and pump 122 can then be used to control the blood flow from the compartment to the main vein.

[0698] For some applications, in order to reduce venous pressure in the vein and / or reduce pressure in an organ that draws blood from the vein (e.g., to reduce liver congestion), the pore-covering umbrella 140 ( Fig.11A-C) used to cover a small hole at a confluence between a hepatic vein, intestinal vein, or adrenal vein and another vein of a subject, and a blood pump catheter used to control the blood flow from the hepatic vein, intestinal vein, or adrenal vein and other vein.

[0699] For some applications, the blood pump 150 ( Figure 12Ai -E) placed in an artery supplying an external limb to increase perfusion of the external limb, for example to treat a gangrenous limb. Alternatively or additionally, a blood pump, such as blood pump 150, is placed in an artery, such as the descending aorta, in order to push blood away from the heart, for example to reduce afterload, and / or otherwise improve heart function.

[0700] In general, in the specification and claims of this application, the term "proximal" and related terms, when used in reference to a device or a portion thereof, should be interpreted as referring to an end of the device or the portion thereof, when inserted into a subject's body, typically closer to a position through which the device is inserted into the subject's body. The term "distal" and related terms, when used in reference to a device or a portion thereof, should be interpreted as referring to an end of the device or the portion thereof, when inserted into a subject's body, typically farther from a position through which the device is inserted into the subject's body.

[0701] In general, in the specification and claims of the present application, the term "downstream" and related terms, when used with reference to a blood vessel, or with reference to a portion of a device configured for placement in a blood vessel, should be interpreted as referring to a location in the blood vessel, or a portion of the device, which is intended to be placed in the blood vessel at a location that is downstream, relative to the direction of antegrade blood flow through the blood vessel, relative to a different location in the blood vessel. The term "upstream" and related terms, when used with reference to a blood vessel, or with reference to a portion of a device configured for placement in a blood vessel, should be interpreted as referring to a location in the blood vessel, or a portion of the device, which is intended to be placed in the blood vessel at a location that is upstream, relative to the direction of antegrade blood flow through the blood vessel, relative to a different location in the blood vessel.

[0702] Therefore, according to some applications of the present invention, the following multiple inventive concepts are provided:

[0703] Inventive concept 1: A method for use with multiple tributary veins providing a main vein, comprising:

[0704] Mechanically separate the blood in multiple veins into a compartment separate from the blood flow in the main vein; and

[0705] Blood flow from the plurality of veins to the main vein is controlled by pumping blood from the compartments into the main vein.

[0706] Inventive concept 2: The method according to inventive concept 1 further comprises: performing ultrafiltration on the drawn blood.

[0707] Inventive concept 3: According to the method of inventive concept 1,

[0708] The step of separating the plurality of veins comprises:

[0709] placing a blood-proof sleeve and a spiral support member surrounding the sleeve into the main vein, and

[0710] Using the helical support to connect the sleeve to a wall of the main vein; and

[0711] The step of pumping blood from the compartment to the main vein includes: using the spiral support to guide a distal portion of a blood pump into the compartment and using the blood pump to pump the blood.

[0712] Inventive concept 4: The method according to inventive concept 1, wherein:

[0713] The step of separating the plurality of veins comprises:

[0714] placing a blood-impermeable sleeve and a spiral portion of a blood pump disposed around the sleeve into the main vein, and

[0715] connecting the sleeve to a wall of the main vein: and

[0716] Pumping blood from the compartment into the main vein includes pumping blood into a plurality of access holes of the blood pump defined by the spiral portion of the blood pump.

[0717] Inventive concept 5: The method according to any one of inventive concepts 1-4, wherein:

[0718] The step of separating blood in the plurality of veins into a compartment separate from blood flow in the main vein comprises: separating blood in the plurality of renal veins of the subject into a compartment separate from blood flow in a vena cava of the subject by placing a blood impermeable sleeve into the vena cava of the subject so that a downstream end of the sleeve is connected to a wall of the vena cava at a first location downstream of all the renal veins of the subject and so that an upstream end of the sleeve is connected to the wall of the vena cava at a second location upstream of all the renal veins of the subject; and

[0719] The step of pumping blood from the compartment into the main vein includes operating a pump to pump blood from the compartment to a location within an interior portion in fluid communication with the sleeve.

[0720] Inventive concept 6: According to the method of inventive concept 5, wherein: the step of drawing blood from the compartment includes: drawing blood in a downstream direction through the multiple renal veins.

[0721] Inventive concept 7: According to the method of inventive concept 5, wherein: the sleeve is placed in the vena cava for less than one week, and wherein the step of operating the pump includes: operating the pump for less than one week.

[0722] Inventive concept 8: The method according to inventive concept 5 also includes: identifying the subject as a subject suffering from a condition selected from the group consisting of: heart failure, congestive heart failure, reduced renal blood flow, increased renal vascular resistance, hypertension and renal insufficiency, and the step of operating the pump includes: in response to identifying the subject as suffering from the condition, reducing the blood pressure within the multiple renal veins of the subject by operating the pump.

[0723] Inventive concept 9: According to the method of inventive concept 5, the step of placing the sleeve in the vena cava of the subject includes: anchoring the sleeve to the vena cava by causing the vena cava to surround and compress at least a portion of the sleeve by operating the pump.

[0724] Inventive concept 10: According to the method of Inventive concept 5, wherein: the step of operating the pump to pump blood from the compartment to the position inside a fluid connected to the sleeve includes: operating the pump to pump blood from the compartment to a position in the vena cava upstream of the sleeve.

[0725] Inventive concept 11: According to the method of Inventive concept 5, wherein: the step of operating the pump to pump blood from the compartment to the position inside a fluid connected to the sleeve includes: operating the pump to pump blood from the compartment to a position in the vena cava downstream of the sleeve.

[0726] Inventive concept 12: According to the method of inventive concept 5, the step of placing the sleeve into the vena cava comprises: placing in the vena cava:

[0727] a support configured to define widened upstream and downstream ends thereof, widened relative to a central portion of said support, and

[0728] an anti-blood seepage sleeve connected to the stent, the sleeve defining its trumpet-shaped upstream and downstream ends, connected to the widened upstream and downstream ends of the stent, respectively; and

[0729] Connecting the stent to the blood vessel so that:

[0730] In response to the blood pressure on a first side of at least one of the plurality of flared ends of the sleeve being greater than on a second side of the at least one flared end of the sleeve, blood flows between an outer side of the at least one flared end of the sleeve and an inner wall of the blood vessel, and

[0731] In response to the blood pressure on the first side of the at least one flared end of the sleeve being smaller than that on the second side of the at least one flared end of the sleeve, the at least one flared end of the sleeve blocks the blood flow between the outer side of the at least one flared end of the sleeve and the inner wall of the blood vessel by contacting the inner wall of the blood vessel.

[0732] Inventive concept 13: According to the method of inventive concept 5, the step of placing the sleeve into the vena cava comprises: placing in the vena cava:

[0733] a sleeve configured to define a plurality of flared ends thereof and a narrow central portion located between the plurality of flared ends; and

[0734] A bracket, configured to define:

[0735] a sleeve-support bracket configured to define a plurality of widened ends thereof and a narrow central portion between the plurality of widened ends that is narrower than the plurality of widened ends of the bracket, the sleeve connecting the sleeve-support bracket of the bracket; and

[0736] A vessel-wall-supporting stent is connected to the narrow central portion of the sleeve-supporting stent and protrudes radially from the sleeve-supporting stent.

[0737] Inventive concept 14: According to the method of inventive concept 13, wherein: the step of drawing blood from the compartment includes: drawing blood from a position between an outer side of the sleeve and an inner wall of the vena cava.

[0738] Inventive concept 15: The method according to inventive concept 5, further comprising: inserting the pump into the compartment through an opening in the sleeve by the pump being insertable.

[0739] Inventive concept 16: The method according to inventive concept 15, wherein: the step of inserting the pump through the opening includes: inserting the pump through an opening having a diameter between 2 mm and 10 mm.

[0740] Inventive concept 17: The method according to inventive concept 15, wherein: the step of inserting the pump through the opening includes: inserting the pump through the opening so that the opening forms a seal around the pump.

[0741] Inventive concept 18: The method according to inventive concept 5, further comprising inserting the pump into the compartment through a pump-receiving sleeve protruding from the sleeve.

[0742] Inventive concept 19: According to the method of inventive concept 18, the step of inserting the pump into the compartment through the pump-containing sleeve includes inserting the pump into the compartment through a pump-containing sleeve having a diameter between 2 mm and 10 mm.

[0743] Inventive concept 20: According to the method of inventive concept 18, the step of inserting the pump into the compartment through the pump-containing sleeve includes inserting the pump into the compartment through the pump-containing sleeve so that the pump-containing sleeve forms a seal around the pump.

[0744] Inventive concept 21: A device comprising:

[0745] A blood-proof sleeve;

[0746] at least one support structure configured to connect a first end and a second end of the sleeve to a blood vessel of a subject; and

[0747] A pump is configured to draw blood from an exterior of the sleeve to a location in fluid communication with an interior of the sleeve.

[0748] Inventive concept 22: The device according to inventive concept 21, wherein: the pump is configured to perform ultrafiltration on the blood.

[0749] Inventive concept 23: The device according to inventive concept 21, wherein: the pump is configured to anchor the structure to the blood vessel by causing the blood vessel to surround and compress at least a portion of the structure.

[0750] Inventive concept 24: According to the device of inventive concept 21,

[0751] wherein: the structure comprises a support configured to define a plurality of widened ends thereof, widening relative to a central portion of the support, and

[0752] The sleeve comprises a sleeve connected to the bracket,

[0753] The sleeve defines a plurality of flared ends thereof connected to the plurality of widened ends of the bracket,

[0754] At least one of the plurality of flared ends of the sleeve is configured to act as a valve by at least partially separating from the widened end of the bracket to which it is connected in response to pressure applied to the flared end of the sleeve.

[0755] Inventive concept 25: The device according to inventive concept 21, wherein:

[0756] The support structure includes a spiral support member disposed around the sleeve, and

[0757] A distal portion of the blood pump is configured to be guided to surround the exterior of the sleeve using the helical support.

[0758] Inventive concept 26: The device according to inventive concept 21, wherein:

[0759] The support structure includes a spiral portion of the blood pump disposed around the sleeve and configured to support the sleeve, and

[0760] The pump is configured to draw blood from the exterior of the sleeve by drawing blood into the plurality of access holes of the pump defined by the helical portion of the blood pump.

[0761] Inventive concept 27: The device according to any one of inventive concepts 21-24, wherein:

[0762] The sleeve is configured to define a plurality of flared ends and a narrow central portion between the plurality of flared ends;

[0763] The structure comprises a support configured to define:

[0764] a sleeve-support bracket configured to define a plurality of widened ends thereof, and a narrow central portion located between the plurality of widened ends that is narrower than the plurality of widened ends of the bracket, the sleeve connecting the sleeve-support bracket of the bracket; and

[0765] A vessel-wall-supporting stent is connected to the narrow central portion of the sleeve-supporting stent and protrudes radially from the sleeve-supporting stent.

[0766] Inventive concept 28: The device according to inventive concept 27, wherein: the pump is configured to draw blood from between the outside of the sleeve and an inner wall of the blood vessel by being placed between an outside of the sleeve and the blood vessel-wall-supporting stent.

[0767] Inventive concept 29: The device according to any one of inventive concepts 21-26, wherein: the structure is configured to separate blood within a renal vein of the subject into a compartment separate from the blood flow within a vena cava of the subject, by connecting a downstream end of the sleeve to a wall of the vena cava at a first position downstream of all the renal veins of the subject, and by connecting an upstream end of the sleeve to a wall of the vena cava at a second position upstream of all the renal veins of the subject.

[0768] Inventive concept 30: The device according to inventive concept 29, wherein: the sleeve is configured to be connected to the vena cava for less than one week, and the pump is configured to operate for less than one week.

[0769] Inventive concept 31: The device according to inventive concept 29, wherein: the pump is configured to reduce blood pressure in multiple renal veins of the subject by pumping blood.

[0770] Inventive concept 32: The device according to inventive concept 29, wherein: the pump is configured to pump blood from the compartment to a location within the vena cava.

[0771] Inventive concept 33: The device according to inventive concept 32, wherein: the pump is configured to pump blood from the compartment to a location within the vena cava upstream of the sleeve.

[0772] Inventive concept 34: The device according to inventive concept 32, wherein: the pump is configured to pump blood from the compartment to a location within the vena cava downstream of the sleeve.

[0773] Inventive concept 35: The device according to any of inventive concepts 21-26, wherein: the sleeve is configured to define an opening through which the pump can be inserted.

[0774] Inventive concept 36: The device according to inventive concept 35, wherein: a diameter of the opening is between 2 mm and 10 mm.

[0775] Inventive concept 37: The device according to inventive concept 35, wherein: the size of the opening is set to form a seal around the pump.

[0776] Inventive concept 38: The device according to any one of inventive concepts 21-26, further comprising a pump-accommodating sleeve protruding from the anti-blood seepage sleeve, the pump-accommodating sleeve being configured to accommodate insertion of the pump through the exterior of the anti-blood seepage sleeve.

[0777] Inventive concept 39: The device according to inventive concept 38, wherein: an inner diameter of the pump-containing sleeve is between 2 mm and 10 mm.

[0778] Inventive concept 40: The device according to inventive concept 38, wherein: the pump-receiving sleeve is sized to form a seal around the pump.

[0779] Inventive concept 41: A method comprising:

[0780] placing a stent in a blood vessel at a placement location of the stent; and

[0781] The stent is at least partially anchored to the blood vessel at the placement site by applying a suction force within the blood vessel to compress at least a portion of the stent around the blood vessel.

[0782] Inventive concept 42: According to the method of inventive concept 41, wherein: the blood vessel includes a blood vessel having a predetermined diameter at the placement position, and the step of placing the stent into the blood vessel includes placing the stent having a diameter smaller than the predetermined diameter into the blood vessel.

[0783] Inventive concept 43: According to the method of inventive concept 41, the step of causing the blood vessel to surround and compress at least a portion of the stent includes: oversizing the stent to reduce the anchoring of the stent to the blood vessel to a certain extent relative to if the blood vessel is not surrounded and anchored to at least the portion of the stent.

[0784] Inventive concept 44: A device comprising:

[0785] a stent configured to be placed in a blood vessel at a placement location of the stent;

[0786] A pump is configured to anchor the stent to the blood vessel at the placement site by applying a suction force within the blood vessel to compress at least a portion of the stent around the blood vessel.

[0787] Inventive concept 45: The device according to inventive concept 44, wherein: the blood vessel includes a blood vessel having a predetermined diameter at the placement position, and the stent includes a stent having a diameter smaller than the predetermined diameter.

[0788] Inventive concept 46: A device comprising:

[0789] A stent configured for placement in a blood vessel, the stent being configured to define a plurality of widened ends thereof that are widened relative to a central portion of the stent; and

[0790] a blood-proof sleeve connected to the stent,

[0791] The sleeve defines a plurality of flared ends thereof connected to the plurality of widened ends of the bracket,

[0792] At least one of the plurality of flared ends of the sleeve is configured to act as a valve by at least partially separating from the widened end of the bracket to which it is connected in response to pressure applied to the flared end of the sleeve.

[0793] Inventive concept 47: A method comprising:

[0794] Placing within a blood vessel of a subject:

[0795] a support configured to define widened upstream and downstream ends thereof, widened relative to a central portion of said support, and

[0796] a blood-proof sleeve connected to the stent, the sleeve defining flared upstream and downstream ends thereof connected to the widened upstream and downstream ends of the stent, respectively; and

[0797] Connecting the stent to the blood vessel so that:

[0798] In response to the blood pressure on a first side of at least one of the plurality of flared ends of the sleeve being greater than on a second side of the at least one flared end of the sleeve, blood flows between an outer side of the at least one flared end of the sleeve and an inner wall of the blood vessel, and

[0799] In response to the blood pressure on the first side of the at least one flared end of the sleeve being smaller than that on the second side of the at least one flared end of the sleeve, the at least one flared end of the sleeve blocks the blood flow between the outer side of the at least one flared end of the sleeve and the inner wall of the blood vessel by contacting the inner wall of the blood vessel.

[0800] Inventive concept 48: A device comprising:

[0801] a blood-proof sleeve defining a plurality of flared ends and a narrow central portion between the flared ends; and

[0802] A stent configured for placement within a blood vessel, the stent being configured to define:

[0803] a sleeve-support bracket configured to define a plurality of widened ends thereof and a narrow central portion located between the plurality of widened ends that is narrower than the plurality of widened ends of the bracket, the sleeve connecting the sleeve-support bracket of the bracket; and

[0804] A vessel-wall-supporting stent is connected to the narrow central portion of the sleeve-supporting stent and protrudes radially from the sleeve-supporting stent.

[0805] Inventive concept 49: The device according to inventive concept 48 further includes a blood pump, which is configured to draw blood from between the outside of the sleeve and an inner wall of the blood vessel by being placed between an outside of the sleeve and the blood vessel-wall-supporting stent.

[0806] Inventive concept 50: The device according to inventive concept 48, wherein: a diameter of the narrow central portion of the sleeve is between 8 mm and 35 mm.

[0807] Inventive concept 51: The device according to inventive concept 48, wherein: a maximum diameter of the multiple flared ends of the sleeve is between 10 mm and 45 mm.

[0808] Inventive concept 52: The device according to inventive concept 48, wherein: a ratio of a maximum diameter of the multiple flared ends of the sleeve to a diameter of the narrow central portion of the sleeve is between 1.1:1 and 2:1.

[0809] Inventive concept 53: The device according to inventive concept 48, wherein: a maximum diameter of the vessel-wall-supporting stent is between 10 mm and 50 mm.

[0810] Inventive concept 54: The device according to any one of inventive concepts 48-53, wherein: a ratio of a maximum diameter of the wall-support bracket to a diameter of the narrow central portion of the sleeve-support bracket is between 1.1:1 and 5:1.

[0811] Inventive concept 55: The device according to inventive concept 54, wherein: the ratio is greater than 1.5:1.

[0812] Inventive concept 56: The device according to any one of inventive concepts 48-53, wherein: a length of the sleeve is greater than 6 mm.

[0813] Inventive concept 57: The device according to inventive concept 56, wherein: the length of the sleeve is less than 80 mm.

[0814] Inventive concept 58: The device according to inventive concept 56, wherein: a length of each of the plurality of flared ends of the sleeve is greater than 3 mm.

[0815] Inventive concept 59: The device according to inventive concept 58, wherein: the length of each of the plurality of flared ends of the sleeve is less than 40 mm.

[0816] Inventive concept 60: The device according to inventive concept 56, wherein: a length of the narrow central portion of the sleeve is greater than 3 mm.

[0817] Inventive concept 61: The device according to inventive concept 60, wherein: the length of the narrow central portion of the sleeve is less than 70 mm.

[0818] Inventive concept 62: A method comprising:

[0819] Placing within a blood vessel of a subject:

[0820] a blood-proof sleeve defining a plurality of flared ends and a narrow central portion between the flared ends; and

[0821] A bracket, configured to define:

[0822] a sleeve-support bracket configured to define a plurality of widened ends thereof and a narrow central portion between the plurality of widened ends that is narrower than the plurality of widened ends of the bracket, the sleeve connecting the sleeve-support bracket of the bracket; and

[0823] a vessel-wall-supporting stent connected to the narrow central portion of the sleeve-supporting stent and projecting radially from the sleeve-supporting stent; and

[0824] The stent is connected to the blood vessel by supporting the wall of the blood vessel so that the vessel-wall-supporting stent of the stent holds the blood vessel open, and the sleeve-supporting stent supports the sleeve within the blood vessel.

[0825] Inventive concept 63: The method according to inventive concept 62 further includes placing a pump between the outside of the sleeve and the blood vessel-wall-supporting stent to draw blood from a location between an outer side of the sleeve and an inner wall of the vena cava.

[0826] Inventive concept 64: According to the method of inventive concept 62, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, a diameter of the narrow central portion of the sleeve is between 8 mm and 35 mm.

[0827] Inventive concept 65: According to the method of inventive concept 62, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, a maximum diameter of the multiple flared ends of the sleeve is between 10 mm and 45 mm.

[0828] Inventive concept 66: According to the method of inventive concept 62, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, and the ratio of a maximum diameter of the multiple flared ends of the sleeve to a diameter of the narrow central portion of the sleeve is between 1.1:1 and 2:1.

[0829] Inventive concept 67: According to the method of inventive concept 62, wherein: the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, and a maximum diameter of the blood vessel-wall-supporting stent is between 10 mm and 50 mm.

[0830] Inventive concept 68: According to the method of any one of Inventive concepts 62-67, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, a maximum diameter of the wall-support stent and a diameter of the narrow central portion of the sleeve-support stent are between 1.1:1 and 5:1.

[0831] Inventive concept 69: According to the method of inventive concept 68, wherein: the step of placing the sleeve into the blood vessel includes: placing the sleeve into the blood vessel, and the ratio is greater than 1.5:1.

[0832] Inventive concept 70: According to the method of any one of inventive concepts 62-67, wherein: the step of placing the sleeve into the blood vessel includes: placing the sleeve into the blood vessel, a length of the sleeve is greater than 6 mm.

[0833] Inventive concept 71: According to the method of inventive concept 70, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, the length of the sleeve being less than 80 mm.

[0834] Inventive concept 72: According to the method of inventive concept 70, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, a length of each of the multiple flared ends of the sleeve being greater than 3 mm.

[0835] Inventive concept 73: According to the method of inventive concept 72, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, the length of each of the multiple flared ends of the sleeve being less than 40 mm.

[0836] Inventive concept 74: According to the method of inventive concept 70, wherein: the step of placing the sleeve into the blood vessel includes: placing the sleeve into the blood vessel, a length of the narrow central portion of the sleeve is greater than 3 mm.

[0837] Inventive concept 75: According to the method of inventive concept 74, the step of placing the sleeve into the blood vessel includes placing the sleeve into the blood vessel, the length of the narrow central portion of the sleeve being less than 70 mm.

[0838] Inventive concept 76: A method for operating a blood pump disposed in a blood vessel of a subject, the method comprising:

[0839] placing an occlusive member within the blood vessel, the occlusive member having an occlusive state in which the occlusive member occludes the blood vessel, and a non-occlusive state in which the occlusive member does not occlude the blood vessel;

[0840] drawing blood in a downstream direction from a location on an upstream side of fluid communication with the occlusion member;

[0841] drawing blood into a location of the subject's blood vessel on a downstream side of fluid communication with the occlusion member,

[0842] The pumping of the blood into the subject's blood vessel is performed in a manner to maintain the occluding member in an occlusive state thereof, in which the occluding member occludes the blood vessel.

[0843] Inventive concept 77: The method according to inventive concept 76 further comprises ultrafiltration of the blood before pumping the blood into the location in the subject's blood vessel.

[0844] Inventive concept 78: According to ...

Claims

1. A method for manufacturing a blood pump device, characterized in that: Include: An impeller is manufactured by connecting a material to a structure defining a plurality of helical elongated elements, such that the plurality of helical elongated elements to which the material is connected define one or more blades of the impeller, the connecting being performed by: immersing at least a portion of the structure in the material while the material is in a liquid state; drying said material while said material is supported by a plurality of said spiral elongated elements; as well as During drying of the material, the structure is rotated about its longitudinal axis so as to promote formation of a film of the material having a substantially uniform thickness within the blades of the impeller.

2. The method according to claim 1, characterized in that: The structure defines three of the helical elongated elements, and connecting the material to a plurality of the helical elongated elements includes connecting the material to three of the helical elongated elements such that each of the elongated elements and the material connected thereto define a respective blade of the impeller.

3. The method according to claim 1, characterized in that: The structure defines two of the helical elongated elements, and connecting the material to at least one of the helical elongated elements includes connecting the material to two of the helical elongated elements such that the two helical elongated elements and the material connected thereto define blades of the impeller.

4. The method according to claim 1, characterized in that: The material includes silicone, and drying the material includes curing the silicone.

5. The method according to any one of claims 1 to 4, characterized in that: The method further comprises forming the structure defining a plurality of the helical elongated elements by: cutting a tube such that the cut tube defines an initial structure having a first end and a second end at a proximal end and a distal end of the initial structure, the first end and the second end being interconnected by a plurality of elongated elements; and The plurality of elongated elements are radially expanded and formed into a plurality of helical elongated elements at least in part by axially compressing the initial structure.

6. The method according to claim 5, characterized in that: Radially expanding the plurality of elongated elements and forming the plurality of helical elongated elements further comprises twisting the initial structure.

7. The method according to any one of claims 1 to 4, characterized in that: Connecting the material to the plurality of the elongated elements includes connecting the material to the plurality of the elongated elements such that the material defines a hollow central lumen therethrough, the hollow central lumen facilitating insertion of an axial support member therethrough.

8. The method according to claim 7, characterized in that: The method also includes inserting the axial support member through the hollow central lumen.

9. A method for manufacturing a blood pump device, characterized in that: The method comprises: An impeller is manufactured by connecting a material to a structure defining three or more helical elongated elements, such that each of the three or more helical elongated elements to which the material is connected defines a respective blade of the impeller, the connecting being performed by: Immersing at least a portion of the structure in the material while the material is in a liquid state; and drying the material while the material is supported by three or more of the spiral elongated elements so that the material forms a film having a substantially uniform thickness within each blade of the impeller.

10. The method according to claim 9, characterized in that: Connecting the material to three or more of the spiral elongated elements includes rotating the structure about its longitudinal axis during drying of the material to facilitate forming the film of the material having a substantially uniform thickness.

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