Linear pulsatile cardiac assist pump

Abstract

Described herein is a linearly reciprocating pump to assist in circulating blood within a patient's body. Red blood cell damage can be avoided or minimized by such linear pumping motion. Linearly reciprocating motion can also generate a pulsatile pumping cycle that mimics the natural pumping cycle of the heart. The pump can be configured to reside in various body locations. For example, the pump can be mounted in the right ventricle, left ventricle, ascending aorta, descending aorta, thoracic aorta, or abdominal aorta. In some cases, the pump can be deployed in the venous circulation. In other cases, the pump can reside outside the patient.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Application No. 63 / 152,126, filed February 22, 2021, U.S. Provisional Application No. 63 / 176,817, filed April 19, 2021, and U.S. Provisional Application No. 63 / 299,385, filed January 13, 2022, each of which is incorporated herein by reference in its entirety.

[0002] This application relates generally to blood pumping devices. The devices may be cardiac assist devices or pumps of the type used to supplement or sustain blood flow on a short-term basis. Such devices are generally utilized in the treatment of patients suffering from impaired cardiac function or heart failure in order to stabilize the patient and gain time to implement longer-term treatments. [Background technology]

[0003] The treatment and survival of patients who suffer severe cardiac trauma or heart failure is typically an emergency process. In most cases, the treatment of patients who suffer traumatic heart failure requires immediate life support measures. Essentially, medical personnel must first assist or stabilize the failing heart to maintain systemic circulation until further diagnostic measures are taken or treatment options are determined.

[0004] In some cases, it may be conceivable that a physician may be able to stabilize such patients through the judicious administration of various drugs, but the stabilization process often requires the application of an auxiliary blood pumping device. Generally, such auxiliary blood pumping devices, known in the art as "cardiac assist devices" or "cardiac assist pumps", have had limited success despite the availability of various designs. These cardiac assist pumps generally utilize a miniature pumping device combined with a catheter support that is operatively coupled to an external pump drive and pump control system. The purpose is to insert the pump into the patient's bloodstream at a strategic point to supplement or replace the pumping action of the patient's heart. Although various pump design approaches have been employed, most cardiac assist pumps developed include rotary type pumps, such as turbine impellers or the like.

[0005] Unfortunately, rotary pumps have proven problematic for several reasons. Perhaps the most important limitation of such pumps results from their undesirably high speed operation. By nature, such rotary pumps are required to be operated at higher rotational speeds to provide sufficient pressure and blood flow. Another drawback is that the use of high rotational speed pumps, such as turbines, even on a short-term basis can cause damage to the patient's blood cells, which in turn can endanger the patient's life. As a result, the operating time of cardiac assist pumps employing rotary turbine-type pumping devices is typically limited. In addition to blood cell damage caused by high-speed rotary pumping devices, problems also arise due to the constant flow characteristics of such rotary pumps. It has been found that the constant draw of the rotary pump can interfere with the operation of the heart valves and the pumping action of the heart.

[0006] Therefore, it would be beneficial to have an improved cardiac pump device that avoids excessive damage to blood cells and that is compatible with the pulsatile blood flow and pumping characteristics of the human heart. Summary of the Invention [Means for solving the problem]

[0007] Described herein is a linearly reciprocating pump to assist in circulating blood within a patient's body. Red blood cell damage can be avoided or minimized by such linear pumping motion. The linearly reciprocating motion can also generate a pulsatile pumping cycle that results in a pulsatile blood flow that is compatible with the operation of the patient's heart. The pump may be configured to reside in various body locations. For example, the pump may be mounted in the right ventricle, left ventricle, ascending aorta, descending aorta, thoracic aorta, or abdominal aorta. In some cases, the pump may be placed in the inferior vena cava. In other cases, the pump may reside outside the patient.

[0008] In general, the pump for assisting blood circulation described herein may include an expandable housing and a valve member disposed within the expandable housing that reciprocates linearly therein. The valve member may be, for example, a flexible diaphragm or a valve cone. In addition, the valve member may include an inlet side facing the inlet of the expandable housing and an outlet side facing the outlet side of the expandable housing. The expandable housing may include an inner surface and an expanded configuration and may define a chamber for collecting blood. The flexible diaphragm may have an extended configuration and a collapsed configuration and may include a diaphragm body and a periphery. The valve cone may have an expanded configuration and a collapsed configuration and may include a layer having multiple flaps that allow blood flow into the housing through the valve cone during a filling stroke but prevent blood flow through the valve cone during a pumping stroke. In some cases, the pump includes a housing that is not expandable.

[0009] The valve members may be coupled to a support element having an expanded configuration and a collapsed configuration. The valve members may be structured such that expansion of the support element transforms the valve members into their expanded or extended configuration. In some variations, the support element may be an expandable frame having a conical shape. The expandable frame may be coupled to an actuator and may support the valve cone or flexible diaphragm as it linearly reciprocates within the housing. In other variations, the support element may be a tine support comprising a base and a plurality of tines coupled to the actuator that support the flexible diaphragm in an extended configuration during a pump stroke. The plurality of tines may be flexible and / or elastic and have an expanded configuration and a compressed configuration.

[0010] The pump may include an actuator coupled to the valve member (e.g., a flexible diaphragm, valve cone, or umbrella structure), which may be configured to linearly reciprocate the valve member within the expandable housing to generate the fill stroke and the pump stroke of the pumping cycle. The periphery of the valve member may be configured to maintain contact with the inner surface of the expandable housing during the pump stroke. In some variations, the contact may be maintained for the entire duration of the pump stroke. In other variations, the contact may be maintained for a portion of the pump stroke as long as sufficient pressure is generated to move a desired amount of blood out of the housing during the pump stroke. In further variations, for example, when high pump speeds are required, the valve member may be configured such that there is a slight clearance or gap between the periphery and the inner surface of the housing. The clearance may help to avoid creating excessive friction within the pump. The clearance may also be sized such that the proper pressure is generated over the pump stroke while also avoiding crushing or damaging red blood cells during the pump stroke. Here, the diameter of the valve member in their extended or expanded configuration may be at least about 95 percent of the diameter of the housing in its expanded configuration. For example, the valve member in their extended or expanded configuration may be at least about 95 percent, at least about 96 percent, at least about 97 percent, at least about 98 percent, or at least about 99 percent of the diameter of the housing in its expanded configuration. The pump may be driven by an external linear motor drive and linear motor controller mounted on the end of a catheter outside the patient. The linear motor drive may be operatively coupled to a linearly acting cardiac assist pump by a flexible cable or other flexible actuator. A movable sleeve or sheath may hold the expandable housing and valve member (e.g., flexible diaphragm, valve cone, or umbrella structure) in the collapsed configuration and allow their insertion and advancement to a target location within the circulatory system.

[0011] More specifically, the expandable housing of the pump may comprise a support or scaffold including a proximal end and a distal end. The scaffold may be made of a material including stainless steel, titanium, or alloys thereof. With respect to the proximal and distal ends, they may or may not be tapered. Additionally, the distal end of the scaffold may include an inlet for blood flow during the pump stroke. The proximal end of the scaffold may include an outlet for blood flow during the pump stroke.

[0012] In the expanded configuration, the chamber of the expandable housing may have a diameter ranging from about 12 mm to about 30 mm, including all values ​​and subranges therein. The expandable housing may further include a coating. For example, the expandable housing may include a polymer layer, which may include, but is not limited to, an elastomeric polymer, such as silicone, polyester, polyurethane, fluoropolymer, or combinations thereof. Alternatively, the expandable housing may include a fabric layer bonded to the scaffold. For example, the fabric layer may include a woven material, such as a material woven from buckram or polyester fibers. A film or sheet of a nonwoven material, such as Mylar® plastic film, may also be bonded to the expandable housing.

[0013] The pump may further include a cannula extending from the expandable housing. The cannula may extend from either the proximal or distal end of the expandable housing. The length of the cannula may vary depending on factors such as the intended location of pump placement or the age or size of the patient. For example, the cannula length may range from about 2.5 cm to about 5.0 cm, about 25 cm to about 30 cm, or about 35 cm to about 40 cm. Some variations of the cannula may have a length ranging from about 0.5 cm to about 10 cm, including all values ​​and subranges therein. In these variations, the length of the cannula may be about 0.5 cm, about 1.0 cm, about 1.5 cm, about 2.0 cm, about 2.5 cm, about 3.0 cm, about 3.5 cm, about 4.0 cm, about 4.5 cm, about 5.0 cm, about 5.5 cm, about 6.0 cm, about 6.5 cm, about 7.0 cm, about 7.5 cm, about 8.0 cm, about 8.5 cm, about 9.0 cm, about 9.5 cm, or about 10 cm.

[0014] When the pump includes a valve cone in an expandable housing, the valve cone may include a single layer of material or multiple layers of material coupled to the expandable frame. The multiple layers of material may include a mesh layer, a flow control layer, or a combination thereof. In some cases, a mesh layer may be disposed between the flow control layer and the expandable frame. A woven fabric or an elastomeric polymer may be used to form the mesh layer. Exemplary elastomeric polymers include, but are not limited to, silicone, polyester, polyurethane, fluoropolymer, or combinations thereof. The material layer may be coupled to the expandable frame in any suitable manner, for example, by sewing, sewn, or sewn, by use of an adhesive, by heat sealing, or by welding. The expandable frame may include stainless steel, nickel, titanium, or alloys thereof. Generally, the valve cone has a conical shape, but any shape that can be collapsed to allow advancement through the cannula may be used. When the valve cone is molded into a cone, the multiple layers of material (e.g., mesh and flow control layers) and the expandable frame in their expanded configuration are molded into a cone. As mentioned above, the valve cone may have an inlet side that faces the inlet of the expandable housing and an outlet side that faces the outlet of the expandable housing.

[0015] The flow control layer of the valve cone (also referred to herein as the flow control cone) may also be formed from various polymers, such as elastomeric polymers as described above, or from Mylar® plastic film. The flow control layer may include a plurality of flaps having an open configuration and a closed configuration. Generally, the plurality of flaps are in an open configuration during the filling stroke and in a closed configuration during the pumping stroke. The flow control layer may be cut to generate a plurality of flaps, which may be of any suitable size and shape that allows blood to flow into the housing during the filling stroke. For example, the flaps may have a semicircular, arc, circular, triangular, diamond, square, or rectangular shape. Any suitable number of flaps in the flow control layer may also be employed. For example, a flow control layer including 15 flaps may be useful. The valve cone may be configured such that a greater number of flaps are included when they are smaller in size and a fewer number of flaps are included when they are larger in size. For example, three flaps may be employed when the flaps are larger in size. When the flaps are semicircular in shape, they may have a radius ranging from about 0.50 mm to about 3.0 mm, including all values ​​and subranges therein.

[0016] Some valve members may also include a membrane coupled to a plurality of radially expandable and collapsible struts. The membrane may completely or partially cover the struts and may be formed from any suitable elastomer. Non-limiting examples of elastomers include silicone, polyester, polyurethane, fluoropolymer, or combinations thereof. Exemplary fluoropolymers may be polytetrafluoroethylene (PTFE) or expanded polytetrafluoroethylene (ePTFE). Here, the valve member may also have an open configuration and a collapsed configuration. For example, the valve member may have an umbrella structure. A plurality of struts may support the membrane, and any suitable number of struts may be included. The number of struts may range from 3 to 10, including all values ​​and subranges therein. In general, a valve member including struts may have a collapsed configuration during a filling stroke and an open configuration during a pumping stroke. In some cases, the valve member is comprised of an umbrella structure without an associated expandable frame.

[0017] The length of the struts included within the umbrella structure may vary depending on factors such as the expanded diameter of the housing, the size of the membrane, and the manner of attachment of the struts to the linear actuator, and may range from about 1.0 cm to about 3.0 cm, including all values ​​and subranges therein. Struts having longer lengths may extend beyond the periphery of the membrane. In some cases, the struts include one or more bends along their length. The one or more bends may be provided anywhere along the struts. For example, the one or more bends may be provided at the distal (free) end of the strut and / or at the midpoint of the strut. The bends in the struts may form a bend angle of about 5 degrees to about 15 degrees, including all values ​​and subranges therein, with respect to the longitudinal axis of the umbrella structure.

[0018] The struts may have one or more sections, and the one or more sections may have any suitable shape or geometry. The cross-sectional shape of the struts may be circular, oval, triangular, square, or rectangular. The struts may have different cross-sectional shapes along their length. For example, the struts may have one or more sections with a circular cross-sectional shape and one or more sections with a rectangular cross-sectional shape. In some cases, the struts may include three sections, two end sections and a middle section therebetween. The end sections may have a circular cross-sectional shape and the middle section may have a rectangular cross-sectional shape. The rectangular cross-sectional shape may provide the middle section with a flattened profile. In some variations, different sections of the struts may have different widths. For example, when the struts include three sections (two end and one middle section), the middle section may be wider than the two end sections. The distal tips of the struts may be rounded to help prevent the struts from damaging the inner surface of the housing during the pump stroke. Radiopaque markers may also be provided at any suitable location along the length of one or more struts, for example, at the distal end of one or more struts (e.g., one-third of a strut, half of a strut, all of a strut).

[0019] The umbrella structure may further include an anchor having a proximal end and a distal end. The proximal end may be configured to be attached to a linear actuator of the pump. The distal end may be configured to be attached to the plurality of struts. When the umbrella structure is in its expanded configuration, the plurality of struts may diverge radially outward from the distal end of the anchor to generate a strut angle relative to a longitudinal axis of the umbrella structure. The strut angle may range from about 30 degrees to about 60 degrees, including all values ​​and subranges therein.

[0020] The mesh layer may be used to support the flow control layer so that when pressure against the flaps is applied during the pump stroke, the flaps are not pushed through the openings in the expandable frame. Thus, the mesh layer may help maintain the flaps in a closed configuration during the pump stroke when blood is moved out of the housing through the housing outlet. However, during the fill stroke, the mesh layer allows blood to flow from the housing inlet through the holes in the mesh and then through the flaps, transitioning them to their open configuration so that blood can move to the outlet side of the valve cone. In some cases, for example, when the openings in the expandable frame are smaller than the flaps, the valve cone may not include a mesh layer.

[0021] In addition to the rim, the flow control layer may include a body. The body and rim may be made of the same material or of different materials. Additionally, the body and rim may be separate components or integrally formed with each other. When provided as separate components, the body may be formed of an elastomeric polymer or of Mylar® plastic film, and the rim may be an O-ring. The peripheral edge of the flow control layer may be wrapped over the O-ring to form the rim. The thickness of the rim may exceed the thickness of the body. The body may have a thickness ranging from about 0.03 mm to about 0.05 mm. The rim may have a thickness ranging from about 0.20 mm to about 1.5 mm. In some cases, the thickness of the rim and the body may be equal.

[0022] Some variations of the valve member include a flexible diaphragm contained within an expandable housing. The flexible diaphragm may include an elastomeric polymer. Non-limiting examples of elastomeric polymers include silicone, polyester, polyurethane elastomers, fluoropolymers, or combinations thereof. Exemplary fluoropolymers may include polytetrafluoroethylene (PTFE) or expanded polytetrafluoroethylene (ePTFE). The body and rim of the flexible diaphragm may include the same material or different materials. In some cases, the diaphragm body and rim are integrally formed. The thickness of the diaphragm body may range from about 0.03 mm to about 0.3 mm. With respect to the rim of the diaphragm, the thickness may range from about 0.70 mm to about 1.5 mm. The thickness of the rim may exceed the thickness of the diaphragm body, which may allow the flexible diaphragm to be in its collapsed configuration during the filling stroke and in an extended configuration during the pumping stroke of the pumping cycle. However, in some variations, the periphery and the body may have the same thickness. The periphery of the flexible diaphragm may have a width ranging from about 1 mm to about 2 mm.

[0023] Further, the flexible diaphragm may have any suitable shape or geometry capable of creating a seal between the periphery of the diaphragm and the inner surface of the expandable housing during a pump stroke. For example, the flexible diaphragm may have a conical shape when in an extended configuration. A plurality of ribs extending from a central portion of the diaphragm body to the periphery may be employed to maintain the conical shape during a pump stroke. The plurality of ribs may have a rib angle between the ribs and an axis perpendicular to the actuator ranging from about 30 degrees to about 60 degrees. The plurality of ribs may be equally spaced from one another. In some variations, the plurality of ribs may be unequally spaced from one another. Some variations of the pump may also include a tine support comprising a base and a plurality of tines coupled to the actuator that support the flexible diaphragm in the extended configuration during a pump stroke. The plurality of tines may be flexible and / or elastic and have an expanded configuration and a compressed configuration. In other variations, the flexible diaphragm may be coupled to an expandable frame that is conically shaped. Coupling to the expandable frame may be accomplished in any suitable manner, for example, by sewing, stitching, or suturing, by use of adhesive, by heat sealing, or by welding.

[0024] Some of the pumps described herein may include a valve member with an element that limits its expansion. For example, the valve member may include an expandable frame bonded to a polymer layer, where a number of control lines or tethers attach the valve member to a pump actuator. The tethers may have a relaxed state and a tensioned state, and may have a length that limits the expansion of the valve member so that it contacts and creates a seal with the inner surface of the pump housing during the pump stroke of a pumping cycle without creating excessive friction. The length of the tether may also be adjusted so that a small gap is created between the valve member and the inner surface of the pump housing during the pump stroke. During the filling stroke, the valve member may collapse to a collapsed configuration, which in turn may move the tethers to the relaxed state. During the pump stroke, the valve member may expand to an expanded configuration, which may transition the tethers from the relaxed state to the tensioned state.

[0025] In some cases, the expandable housing of the pump may include multiple openings or perforations. The number of openings utilized may range from about 2 to about 25. The openings may be equally or unequal spaced on a portion of the expandable housing. Additionally, the multiple openings may have a diameter ranging from about 0.10 mm to about 6.50 mm. When the expandable housing includes openings, a skirt may also be coupled to the expandable housing that surrounds the multiple openings.

[0026] Any component of the pumps described herein may be coated. For example, one or more of the cannula, expandable housing, expandable frame, valve cone, flexible diaphragm, and umbrella strut may be coated. The pump components may be fully or partially coated. The coating may provide increased lubricity and / or wettability to the portion of the pump that is coated, or may provide anti-fouling, anti-proliferative, or anti-bacterial properties to the pump.

[0027] The coating may generally comprise a polymeric material. Exemplary polymeric materials may include, but are not limited to, hydrophilic polymers, hydrophobic polymers, or a mixture of these two types of polymers. The coating may be a single layer on the pump component, or may comprise multiple layers. When multiple layers are employed, each layer may be made from the same polymer or from different polymers. Coatings comprising polytetrafluoroethylene (PTFE) or expanded polytetrafluoroethylene (ePTFE) may be useful.

[0028] There are several variations in which the pump may be placed in a console external to the patient. A coaxial catheter coupled to the pump housing provides continuous and pulsatile blood flow between the patient and the external pump and may have a diameter of about 10F to 18F. The coaxial catheter may include an inflow lumen and an outflow lumen. The inflow lumen may generally have a diameter greater than about 5F.

[0029] A method for pumping blood is further described herein. The method generally includes advancing a pump to a target location within a patient's circulatory system, the pump including an expandable housing having an inner surface, an expanded configuration, and a collapsed configuration. The pump may further include a valve member that reciprocates linearly within the housing. An exemplary valve member may be a valve cone, a flexible diaphragm, or an umbrella structure including multiple layers of material coupled to an expandable frame. The membranes of the valve cone, the flexible diaphragm, and the umbrella structure may include a body and a periphery, the valve cone having an expanded configuration and a collapsed configuration, the flexible diaphragm having an extended configuration and a collapsed configuration, and the umbrella structure having an expanded and collapsed configuration. Once at the target location, the expandable housing may be expanded to an expanded configuration, and the valve cone, the flexible diaphragm, or the umbrella structure contained therein may be linearly reciprocated to generate a filling stroke and a pumping stroke of a pumping cycle. During the pump stroke, contact between the periphery of the valve member and the inner surface of the expandable housing may be maintained such that a seal is created to prevent blood flow between the periphery and the inner surface. Additionally, during the pump stroke, blood is drawn into the expandable housing. Depending on the variation of the pump used, blood may be drawn into the expandable housing from the left ventricle or the aorta. The pump stroke may generally push blood out of the expandable housing into a portion of the aorta, for example the ascending aorta or the descending aorta. During the pumping cycle, a flap in the flow control layer of the valve cone closes during the pump stroke and opens during the fill stroke. When a flexible diaphragm is employed, it may collapse to a collapsed configuration during the fill stroke and extend to an extended configuration during the pump stroke. Similarly, when linearly reciprocated, the umbrella structure may collapse to a collapsed configuration during the fill stroke and expand to an extended configuration during the pump stroke.

[0030] The pump may be advanced and positioned in various portions of the patient's circulatory system. For example, the expandable housing of the pump may be advanced through an arterial vessel, such as through the femoral artery, the aorta, and the aortic valve, into the patient's left ventricle. When the pump further comprises a cannula, the cannula may also be advanced through the aortic valve into the patient's left ventricle. Non-limiting examples of target locations for the expandable housing include the aortic arch, the descending aorta, the thoracic aorta, and the abdominal aorta. In some cases, the expandable housing of the pump may be advanced within the descending aorta and specifically positioned to assist in perfusion of the patient's kidneys. For example, the expandable housing may be positioned within the descending aorta near the renal arteries to assist in renal perfusion.

[0031] In addition to the arterial vessel, the pump may be advanced and positioned within the venous circulation. For example, the pump's expandable housing may be advanced within the inferior vena cava to a location between the hepatic vein and the right atrium of the heart. Once in this location, the pump may draw blood toward the heart and increase circulation from the lower extremities and from the liver. The pump may be positioned at various locations between the hepatic vein and the right atrium. In some variations, the expandable housing is placed closer to the hepatic vein than to the right atrium. In one variation, for example, when the pumps are placed within the venous circulation, they may include a housing chamber (flow chamber) without an associated cannula.

[0032] As explained above, the expandable housing may include a plurality of openings or perforations and a skirt coupled to the expandable housing. In this case, blood exiting the openings may be directed by the skirt in a retrograde direction toward the patient's heart during the pump stroke. The length of the skirt may be adjusted to achieve a predetermined amount of retrograde blood flow toward the patient's heart. The number of openings may also be adjusted to achieve a predetermined amount of retrograde blood flow toward the patient's heart. Alternatively, the diameter of the openings may be adjusted to achieve a predetermined amount of retrograde blood flow toward the patient's heart. Adjustment of any one or combination of the aforementioned features may be utilized such that about 60% of the blood from the pump stroke flows in a retrograde direction toward the patient's heart, about 50% of the blood from the pump stroke flows in a retrograde direction toward the patient's heart, or about 40% of the blood from the pump stroke flows in a retrograde direction toward the patient's heart.

[0033] When the pump is disposed external to the patient, a method for pumping blood may include accessing the patient's circulatory system with a coaxial catheter and coupling the coaxial catheter to a housing of the pump. The housing may have an interior surface. A flexible diaphragm contained within the housing may comprise a diaphragm body and a periphery, the flexible diaphragm having an extended configuration and a collapsed configuration. Alternatively, a valve cone may be disposed within the housing and linearly reciprocate therein. The external pump may be disposed within or attached to a console that includes a user interface.

[0034] Access to the circulatory system may be obtained from any suitable artery or vein, for example, the femoral, subclavian, carotid, or jugular artery. Once access is obtained, the coaxial catheter may be advanced to a target location within the circulatory system, and a valve member, for example, a valve cone, a flexible diaphragm, or an umbrella structure, may be linearly reciprocated within the expandable housing to generate the fill stroke and the pump stroke of a pumping cycle. During the pump stroke, contact between the periphery of the valve cone, the flexible diaphragm, or the umbrella structure and the inner surface of the expandable housing may be maintained to create a seal therebetween and prevent blood from flowing around the flexible diaphragm. The seal may help to generate and maintain the force of the pump stroke and minimize red blood cell damage that may occur due to blood flowing between the space that exists between the periphery and the inner surface. The methods described herein may include advancing the coaxial catheter to various target locations within a patient. For example, the target location for the inflow lumen may be the patient's left ventricle, or the target location for the outflow lumen may be above the patient's aortic valve.

[0035] The coaxial catheter may include an inflow lumen and an outflow lumen. The inflow lumen may receive blood from the left ventricle and the outflow lumen may return blood to the ascending aorta. In general, the pump stroke may pull blood into the housing through the inflow lumen and push blood out of the housing through the outflow lumen. During the filling stroke, the flexible diaphragm may be collapsed to a collapsed configuration. Correspondingly, the flexible diaphragm may be extended to an extended configuration during the pumping stroke. When a valve cone is used, a plurality of flaps in the flow control layer may be opened during the filling stroke and closed during the pumping stroke. A mesh layer may comprise the flow control layer to support the flaps and prevent them from opening during the pumping stroke.

[0036] Other methods for pumping blood may include advancing a pump to a target location within a patient's aorta, such as the thoracic aorta or abdominal aorta, the pump having a fill stroke and a pump stroke, drawing a fill volume of blood into the pump during the pump stroke, and pushing an exit volume of blood out of the pump during the pump stroke, the exit volume comprising a first portion of blood and a second portion of blood. The fill stroke may draw blood from the patient's left ventricle. Additionally, the first portion of blood may be pumped in a retrograde direction toward the patient's head, and the second portion of blood may be pumped in an antegrade direction. The second portion of blood may be about 60% of the exit volume, about 50% of the exit volume, or about 40% of the exit volume.

[0037] In some methods, an expandable housing, having a cannula extending from a proximal end of the housing, is advanced within a selected artery and positioned at a target location, such as the aorta and left ventricle of a patient. The selected artery may be the femoral artery. Once at the target location, a sheath surrounding the expandable housing may be retracted, thereby allowing the expandable housing to expand to its pumping configuration. An actuator may then be advanced within the housing, and a linear motor drive may be activated to induce reciprocating motion of a valve member (e.g., a valve cone or flexible diaphragm) coupled thereto within the expandable housing in forward and backward directions. During the reciprocating motion, the forward motion may induce blood flow within the housing, and the backward motion may impart a pumping force to the blood within the housing. The result is a linear pulsatile pumping action that may be highly efficient and may match the pulsatile behavior of the human heart. The reciprocating motion characteristics of the pumps described herein may be independently varied to provide optimized forward stroke, backward stroke, and motion profiles.

[0038] A system for pumping blood is also described herein. The system may generally include a pump, the pump comprising an expandable housing having an inner surface and an expanded configuration. A valve member including a periphery may be disposed within the expandable housing and may have an expanded or extended configuration and a collapsed configuration. The pump may also include an actuator coupled to the valve member that linearly reciprocates the valve member within the housing to generate a pump stroke and a fill stroke of a pumping cycle. During the pump stroke, the periphery of the valve member may be configured to maintain contact with the inner surface of the housing. In some variations, the contact may be maintained for the entire duration of the pump stroke. In other variations, the contact may be maintained for a portion of the pump stroke as long as sufficient pressure is generated to move a desired amount of blood out of the housing during the pump stroke. In further variations, for example, when high pump speeds are required, the valve member may be configured such that there is a slight clearance or gap between the periphery and the inner surface of the housing. The clearance may help to avoid creating excessive friction within the pump. The gap may also be sized such that the proper pressure may be generated over the pump stroke while also avoiding crushing or damaging the red blood cells during the pump stroke, where the diameter of the valve members in their extended or expanded configuration may be at least about 95 percent of the diameter of the housing in its expanded configuration, for example, the valve members in their extended or expanded configuration may be at least about 95 percent, at least about 96 percent, at least about 97 percent, at least about 98 percent, or at least about 99 percent of the diameter of the housing in its expanded configuration.

[0039] Additionally, the system may include a console, external to the patient, containing a controller configured to adjust the actuators. A user interface may be coupled to the controller and configured to manually set or adjust pump and / or patient parameters and / or display pump and patient parameters. The user interface may be a display forming part of the console that houses the linear actuators. The console may be a stationary component of the system or a mobile component when coupled to a wheeled cart or other rolling base.

[0040] Exemplary pump parameters include, but are not limited to, pump cycles per minute and pump cycle duration. When setting or adjusting the pump cycle duration, the duration of either the fill stroke or the pump stroke may be set or adjusted. Non-limiting examples of patient parameters include age, height, weight, left ventricular pressure, left ventricular end diastolic pressure, aortic pressure, and systemic blood pressure. The system may provide an audible and / or visual alert when any pump or patient parameter is above or below a preset value or above or below a preset range of values.

[0041] In use, the pump of the system may be advanced to a target location within the patient's circulatory system. The pump may comprise an expandable housing including an inner surface, an expanded configuration, and a collapsed configuration, and a valve member with a periphery disposed within the expandable housing, as described above. Once at the target location, the expandable housing may be expanded from the collapsed configuration to the expanded configuration. Pump parameters and / or patient parameters may be determined, and the valve member may be linearly reciprocated within the expandable housing according to those parameters to generate a filling stroke and a pump stroke. During the pump stroke, contact between the periphery of the valve member and the inner surface of the expandable housing may be maintained. As mentioned above, the pump parameters may include pump cycles per minute, the duration of the pump cycle, or both. When setting or adjusting the duration of the pump cycle, the duration of either the filling stroke or the pump stroke may be set or adjusted, or both may be set or adjusted. When pump parameters are determined, they may be based on patient parameters such as age, height, weight, left ventricular pressure, left ventricular end diastolic pressure, aortic pressure, or systemic blood pressure.

[0042] The pump and patient parameters may be displayed on a user interface. The parameters may be continuously or intermittently monitored and the measurements may be continuously or intermittently displayed on the user interface. The user interface may be a display forming part of a console that houses the linear actuator. The console may be a stationary component of the system, as mentioned above, or a mobile component when coupled to a wheeled cart or other rolling base. The pump and patient parameters may be manually adjusted via buttons on the user interface. In some cases, the display of the user interface includes touch-sensitive buttons for manually adjusting the parameters. In other cases, the pump parameters may be automatically adjusted based on the measured patient parameters.

[0043] The pump of the system may be advanced to a target location within an artery. When the artery is the aorta, the target location may be the ascending aorta, the aortic arch, the thoracic aorta, the descending aorta, or the abdominal aorta. The pump may also be advanced to a target location within a vein. The vein may be the inferior vena cava. When advanced within the inferior vena cava, the target location may reside between the hepatic vein and the right atrium. At this location, the pump may increase circulation from the liver or from the lower extremities. Another target location for the pump may be above or below the renal vein. Yet another target location may be within the aorta, either above or below the renal artery. Pumps positioned at these target locations may assist in perfusion of the kidney as part of a treatment for cardiorenal syndrome due to acute or chronic heart failure or reduced renal perfusion due to other causes. [Brief description of the drawings]

[0044] [Figure 1] FIG. 1 depicts a perspective view of an example pump and linear motor drive.

[0045] [Diagram 2] FIG. 2 depicts the pump of FIG. 1 being advanced within the aorta into the left ventricle of the heart.

[0046] [Diagram 3] FIG. 3 illustrates the blood movement resulting from the pumping stroke of the pump of FIG.

[0047] [Figure 4] FIG. 4 illustrates the filling stroke of the pump of FIG.

[0048] [Diagram 5] FIG. 5 depicts an enlarged cross-sectional view of the pump of FIG. 1 prior to deployment within the heart.

[0049] [Figure 6] FIG. 6 depicts an enlarged cross-sectional view of the pump of FIG. 1 at a midpoint during its configuration for pumping operation.

[0050] [Figure 7] FIG. 7 depicts an enlarged cross-sectional view of the pump of FIG. 1 upon completion of its configuration for pumping operation.

[0051] [Figure 8] FIG. 8 depicts an enlarged cross-sectional view of the pump of FIG. 1 during the fill stroke portion of its pumping operation.

[0052] [Figure 9] FIG. 9 depicts an enlarged cross-sectional view of the pump of FIG. 1 during a pumping stroke portion of its pumping operation.

[0053] [Figure 10] 10A-10C depict side views of an exemplary housing comprising a scaffold and a barrier layer. The scaffold is shown in Fig. 10A and the barrier layer is shown in Fig. 10B. In Fig. 10C, the scaffold is shown coupled to the barrier layer.

[0054] [Figure 11] FIG. 11 depicts a perspective view of an exemplary pump including the housing of FIG. 10C and a flexible diaphragm supported by a plurality of tines.

[0055] [Figure 12] Figures 12A and 12B depict close-up views of a flexible diaphragm according to one variation: Figure 12A shows a top view of the flexible diaphragm, and Figure 12B shows a side cross-sectional view of the diaphragm of Figure 12A taken along line AA.

[0056] [Figure 13] 13A-13C depict close-up views of tines according to one variation: Fig. 13A shows a side view of the tines, Fig. 13B shows a side cross-sectional view of the tines of Fig. 13A taken along line AA, and Fig. 13C shows a front view of the tines of Fig. 13A illustrating their spacing from one another.

[0057] [Figure 14] Figures 14A-14C depict close-up views of another exemplary design for the tines: Figure 14A shows a side view of the tines, Figure 14B shows a side cross-sectional view of the tines of Figure 14A taken along line AA, and Figure 14C shows a front view of the tines of Figure 14A illustrating their spacing from one another.

[0058] [Figure 15] FIG. 15 depicts a perspective view of another exemplary pump including a conical flexible diaphragm.

[0059] [Figure 16] Figures 16A-16C depict close-up views of the conical flexible diaphragm of Figure 15. Figure 16A shows a top view of the diaphragm of Figure 15, Figure 16B shows a side view of the diaphragm of Figure 16A, and Figure 16C shows a side cross-sectional view of the diaphragm of Figure 16B.

[0060] [Figure 17] FIG. 17 illustrates the formation of a seal between an exemplary conical flexible diaphragm and an inner surface of a housing.

[0061] [Figure 18A] 18A and 18B depict a pump according to another variation in which the housing lacks a cannula extending therefrom. Fig. 18A shows the pump positioned in the descending thoracic portion of the aorta. Fig. 18B shows the pump positioned in the descending abdominal portion of the aorta. [Figure 18B] 18A and 18B depict a pump according to another variation in which the housing lacks a cannula extending therefrom. Fig. 18A shows the pump positioned in the descending thoracic portion of the aorta. Fig. 18B shows the pump positioned in the descending abdominal portion of the aorta.

[0062] [Figure 19] FIG. 19 depicts an example pump comprising a housing including a plurality of openings and a skirt coupled to the housing.

[0063] [Figure 20] FIG. 20 depicts an enlarged view of the housing of FIG. 19 with cutouts to show how the skirt and multiple openings cooperate with the flexible diaphragm to generate retrograde blood flow.

[0064] [Figure 21] FIG. 21 illustrates how blood flows during a pumping cycle, including retrograde and antegrade flow.

[0065] [Figure 22] Figures 22A-22C depict a pump according to yet another variation coupled to a linear motor drive external to the patient: Figure 22A shows the pump within the patient and coupled to a linear motor drive in an external console, Figure 22B shows a close-up view of the pump housing within the patient, and Figure 22C shows a close-up view of the distal end of the cannula within the left ventricle.

[0066] [Figure 23] 23A-23C depict an exemplary external pump located in a bedside console that is coupled to a patient via a coaxial catheter. Fig. 23A shows the coaxial catheter in the patient and coupled to a linear motor drive in the bedside console, Fig. 23B shows a close-up view of the inflow and outflow lumens of the coaxial catheter, and Fig. 23C shows a close-up view of the inlet and outlet of the coaxial catheter.

[0067] [Figure 24] Figures 24A-24C depict example locations for pressure sensor attachment to a pump: Figure 24A shows a perspective view of the pump and pressure sensors, Figure 24B shows a close-up of two pressure sensors at the outlet of the pump, and Figure 24C shows a close-up of two pressure sensors at the inlet of the pump.

[0068] [Diagram 25]25A-25C depict an exemplary valve member including an expandable frame, a mesh cone, and a flow control cone: Fig. 25A shows the mesh cone and flow control cone coupled to the expandable frame, Fig. 25B shows an assembled view of the expandable frame, mesh cone, and flow control cone, and Fig. 25C shows the mesh cone and flow control cone sewn to the expandable frame at multiple attachment points.

[0069] [Figure 26]

[0023] Figures 26A-26C depict the expandable frame shown in Figures 25A and 25B. Figure 26A shows a perspective view of the expandable frame, Figure 26B shows a side view of the expandable frame, and Figure 26C shows a top view of the expandable frame.

[0070] [Figure 27] Figures 27A and 27B depict the mesh cone of Figures 25A-25C. Figure 27A shows a circular piece of mesh, including a free edge, that can be rolled into the cone shape shown in Figure 27B.

[0071] [Figure 28] Figures 28A-28C depict the flow control cone of Figures 25A-25C: Figure 28A shows a circular piece of material including multiple flaps and a free edge, Figure 28B shows a peripheral edge that extends circumferentially about the periphery of the material, and Figure 28C shows a circular piece of material that is rolled into a cone shape.

[0072] [Figure 29] 29A and 29B depict another example valve member that includes multiple flaps.

[0073] [Figure 30A] 30A-30D depict a further variation of a valve member that includes multiple struts in an umbrella structure and a membrane. [Figure 30B] 30A-30D depict a further variation of a valve member that includes multiple struts in an umbrella structure and a membrane. [Figure 30C] 30A-30D depict a further variation of a valve member that includes multiple struts in an umbrella structure and a membrane. [Figure 30D] 30A-30D depict a further variation of a valve member that includes multiple struts in an umbrella structure and a membrane.

[0074] [Diagram 31] FIG. 31 depicts an exemplary valve member that includes multiple tethers that limit its expansion.

[0075] [Figure 32A] 32A and 32B depict an exemplary controller console and user interface. [Figure 32B] 32A and 32B depict an exemplary controller console and user interface.

[0076] [Diagram 33] 33 depicts an exemplary pump that lacks a cannula and includes a housing chamber. The pump is shown positioned in the descending aorta above the renal arteries.

[0077] [Diagram 34] FIG. 34 depicts a view of another exemplary expandable frame supporting a flexible diaphragm.

[0078] [Figure 35A] 35A-35B depict perspective and side views of an exemplary umbrella structure including struts completely covered by a membrane. [Figure 35B] 35A-35B depict perspective and side views of an exemplary umbrella structure including struts completely covered by a membrane.

[0079] [Figure 35C] FIG. 35C depicts a side view of another example umbrella structure including bends in multiple struts.

[0080] [Figure 36A] 36A-36C depict views of additional exemplary umbrella structures including longer struts that are partially covered by a membrane. [Figure 36B] 36A-36C depict views of additional exemplary umbrella structures including longer struts that are partially covered by a membrane. [Figure 36C] 36A-36C depict views of additional exemplary umbrella structures including longer struts that are partially covered by a membrane.

[0081] [Figure 37] FIG. 37 depicts a side view of another exemplary variation of the expandable housing in its expanded configuration.

[0082] [Figure 38] FIG. 38 depicts another exemplary variation of a valve member that includes a plurality of posts that are fixed to a linear actuator at one end and are slidable over the linear actuator at the other end.

[0083] [Figure 39] 39A-39B depict an exemplary variation of an inverted umbrella structure.

[0084] [Diagram 40] FIG. 40 depicts an exemplary variation of the strut distal end in an umbrella structure.

[0085] [Diagram 41] FIG. 41 depicts another exemplary variation of the post distal end.

[0086] [Figure 42A] 42A-42C depict further example umbrella structures in which the struts include bends and openings at their distal ends, with Fig. 42A being a side view of the umbrella structure, Fig. 42B being an end view of the umbrella structure, and Fig. 42C providing an assembly view of the umbrella structure. [Figure 42B]42A-42C depict further example umbrella structures in which the struts include bends and openings at their distal ends, with Fig. 42A being a side view of the umbrella structure, Fig. 42B being an end view of the umbrella structure, and Fig. 42C providing an assembly view of the umbrella structure. [Figure 42C] 42A-42C depict further example umbrella structures in which the struts include bends and openings at their distal ends, with Fig. 42A being a side view of the umbrella structure, Fig. 42B being an end view of the umbrella structure, and Fig. 42C providing an assembly view of the umbrella structure.

[0087] [Diagram 43] FIG. 43 depicts an example cell shape formed by the struts of the expandable housing.

[0088] [Diagram 44] FIG. 44 depicts an exemplary diamond shaped cell shape formed by the struts of the expandable housing.

[0089] [Diagram 45] FIG. 45 depicts an exemplary expandable housing that includes multiple parallel struts.

[0090] [Diagram 46] 46A-46B depict an exemplary housing having an enlarged end.

[0091] [Figure 47] 47A-47B depict another exemplary housing having an enlarged end.

[0092] [Figure 48] FIG. 48 depicts a further exemplary valve member that includes a hinge to assist in collapsing the post during the filling stroke of the pumping cycle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0093] (Detailed Description) Described herein is a pump for assisting blood circulation. Instead of a rotating impeller, the pump may include a linearly reciprocating member for moving blood, which may help to avoid shear forces that cause red blood cell damage, and pump blood in a pulsatile manner, mimicking the natural pumping cycle of the heart. The pump may generate a pressure wave or back pulse during the filling stroke to assist the associated heart action, eliminating blood vessel collapse. Additionally, the pump may be capable of providing adequate blood flow at operating speeds of 50 to 500 cycles per minute, which provides a very slow movement compared to a rotating impeller and may prevent red blood cell hemolysis. At slow pump speeds, less heat is generated than with a rotating impeller, avoiding the need to include a cooling device.

[0094] In some cases, linearly reciprocating pumps may be used to increase renal perfusion. The kidneys perform several important functions, including maintaining overall fluid balance, regulating and filtering minerals from the blood, and filtering waste products from food, drugs, and toxic substances. Thus, when blood flow through the kidneys is reduced, fluids may be retained and waste products may build up to dangerous levels within the body. Reduced renal perfusion may occur in patients with acute or chronic heart failure (e.g., cardiorenal syndrome), where lower cardiac output results in reduced renal blood flow, or the patient may suffer from a medical condition, such as diabetes or hypertension, that affects the small blood vessels within the kidney. The pumps described herein may assist in perfusion of the kidney as part of the treatment of cardiorenal syndrome due to acute or chronic heart failure or reduced renal perfusion due to other causes. The renal perfusion pump may be advanced to a target location within the aorta, either above or below the renal artery, to assist circulation to the renal artery.

[0095] The linearly reciprocating member may include a valve constructed such that a seal is created between it and the housing during the pump stroke of the pumping cycle, thereby generating the blood pressure required to move blood, for example, peripherally to the renal artery. The pump stroke and length of the linearly reciprocating member, and the stroke speed may be independently adjustable. Blood pressure and blood flow rate may be controlled by stroke length and speed adjustment. Additionally, adjustable back and forth stroke speed ramping may avoid perturbations in the pressure characteristics of the circulatory system. The pump may be placed in various parts of the patient's circulatory system, such as the left ventricle, right ventricle, and aorta. The pump may be used to assist renal perfusion when placed in the descending aorta above or below the renal arteries. In some cases, it may be useful to have the pump external to the patient.

[0096] (pump) The pump for assisting blood circulation described herein may include a housing and a linearly reciprocating member with a valve, e.g., a flexible diaphragm, a valve cone, an umbrella structure, or an inverted umbrella structure, disposed within the housing. The housing may be expandable and may include an inner surface, an expanded configuration, and a collapsed configuration. A sheath, which may be concentrically disposed about the housing, may maintain the housing in the collapsed configuration during advancement to the target location. Upon reaching the target location, the sheath may be retracted to allow expansion of the housing to the expanded configuration. The diameter of the sheath may vary depending on the diameter of the pump housing, which in turn may depend on factors such as whether the pump is located within or outside the body, the utility of use, the age or size of the patient, etc. In variations in which the pump is used within the body, specifically within an artery, it may be beneficial for the sheath to be relatively small and flexible. For example, the diameter of the sheath may be about 9F, about 10F, about 11F, about 12F, about 13F, about 14F, or any diameter between about 9F and about 14F, including all values ​​and subranges therein. Additionally, when the valve member is a flexible diaphragm, the flexible diaphragm may have an extended configuration and a collapsed configuration and may include a diaphragm body and a periphery. Similarly, when the valve member is a valve cone, the valve cone may have an expanded configuration and a collapsed configuration and may include a layer having multiple flaps that allow blood flow into the housing during a fill stroke but prevent blood flow through the valve cone during a pump stroke. Bearings within the expandable housing may also be provided to inhibit movement of the flexible diaphragm or valve cone within the housing.

[0097] The pump may also include an actuator coupled to the valve member (e.g., a flexible diaphragm, valve cone, umbrella structure, or inverted umbrella structure) via a support element, which may be configured to linearly reciprocate the valve member within the housing to generate the fill stroke and the pump stroke of a pumping cycle. The periphery of the valve member may be configured to maintain contact with the inner surface of the housing during the pump stroke. However, the support elements may generally be sized and / or shaped such that they do not contact the inner surface of the housing while they linearly reciprocate within the housing. The pump may be driven by an external linear motor drive and linear motor controller, which may be mounted at the proximal end of the catheter outside the patient. The linear motor drive may be operatively coupled to the pump by a cable or other actuator. Additionally, the pump may be powered by an AC or DC source.

[0098] (Housing) Generally, the pump housing comprises a body, a proximal end, and a distal end. Additionally, the housing may be expandable and include an expanded configuration and a collapsed configuration, as described above. The housing may define a chamber for collecting blood and holding it until it is moved out by the pump stroke, and may comprise a support or scaffold and a covering. The housing may be advanced to a target location within the patient's circulatory system in the collapsed configuration. In response to reaching the target location, the housing may then expand to an expanded configuration to provide a chamber for collection of blood to be pumped. The housing chamber may have a diameter ranging from about 12 mm to about 30 mm, including all subranges therein, in its expanded configuration. For example, the housing chamber may have a diameter of about 12 mm, about 13 mm, about 14 mm, about 15 mm, about 16 mm, about 17 mm, about 18 mm, about 19 mm, about 20 mm, about 21 mm, about 22 mm, about 23 mm, about 24 mm, about 25 mm, about 26 mm, about 27 mm, about 28 mm, about 29 mm, or about 30 mm in its expanded configuration. The diameter may be selected based on factors such as the location where the housing will reside, the age of the patient, and other characteristics, such as whether a cannula, coaxial catheter, skirt, or the like will be utilized with the housing. Additionally, the housing chamber may have a length ranging from about 2.5 cm to about 4.5 cm in its expanded configuration, including all values ​​and subranges therein. For example, the housing chamber may have a length of about 2.5 cm, about 3.0 cm, about 3.5 cm, about 4.0 cm, or about 4.5 cm in its expanded configuration. In some variations, as shown in FIG. 37, the expandable housing 2100 may have a chamber diameter 2102 of about 20 mm and a chamber length 2104 of about 2.9 cm. The cannula length 2108 may be about 1.3 cm. The cannula of the pump device is further described below. Using these measurements, the overall length of the pump residing within the heart below the aortic valve 2106 may be about 8.8 cm.

[0099] The support or scaffold may also include a proximal end and a distal end. The scaffold may be formed from braided, woven, and / or coiled filaments and may be made from a variety of materials. For example, the scaffold material may include biocompatible polymers and metals including stainless steel, titanium, or alloys thereof. For example, the scaffold may include a nickel-titanium alloy (nitinol). With respect to the proximal and distal ends of the scaffold, they may be tapered, blunt, or straight. Additionally, the distal end of the scaffold may include an inlet for blood flow during the pump stroke. The proximal end of the scaffold may include an outlet for blood flow during the pump stroke. In one variation, the scaffold may be a self-expanding stent. In another variation, the scaffold comprises a plurality of struts, which may range in number from 10 to 24. For example, the scaffold may include 10 struts, 11 struts, 12 struts, 13 struts, 14 struts, 15 struts, 16 struts, 17 struts, 18 struts, 19 struts, 20 struts, 21 struts, 22 struts, 23 struts, or 24 struts.

[0100] The housing may further comprise a covering, coating, or layer configured to block blood flow. The covering, coating, or layer may be provided over the entire scaffold or over a section or portion of the scaffold. In one variation, the covering or layer may include a polymer, thus forming a polymer layer. The polymer layer may be overmolded onto the scaffold such that the scaffold is embedded within the polymer layer. In some variations, the scaffold may be positioned within the center of the polymer layer, while in other variations, the scaffold may be positioned toward the inner or outer edge of the polymer layer. Embedding or otherwise completely covering the scaffold with a polymer layer may provide the expandable housing with a smooth inner surface. The polymer layer may include an elastomeric polymer, such as, but not limited to, silicone, polyester, polyurethane, or combinations thereof. Alternatively, the covering or layer may include a fabric, thus forming a fabric layer. In these variations, the expandable housing may include a fabric layer attached to the scaffold, typically to the inner surface of the scaffold. The fabric layer may be bonded to the scaffold by any suitable means, such as, for example, sewing the fabric layer to the scaffold at one or more points (e.g., multiple points). The sewing points may be specifically selected so that the fabric layer forms a smooth surface (e.g., on the interior of the housing) so as not to disrupt the interface between the flexible diaphragm and the housing. In other variations, the fabric layer may be bonded to the scaffold using an adhesive such as an acrylic adhesive, a cyanoacrylate adhesive, or a silicone adhesive. Non-limiting examples of materials that may be used as the fabric layer include woven materials such as buckram or materials woven from polyester fibers. Films or sheets of nonwoven materials such as Mylar® plastic film may also be used.

[0101] In some cases, the pump housing (e.g., coating or layer) may include a plurality of openings or perforations. The number of openings utilized may range from about 2 to about 25, including all values ​​and subranges therein. For example, the expandable housing may include 2 openings, 3 openings, 4 openings, 5 openings, 6 openings, 7 openings, 8 openings, 9 openings, 10 openings, 11 openings, 12 openings, 13 openings, 14 openings, 15 openings, 16 openings, 17 openings, 18 openings, 19 openings, 20 openings, 21 openings, 22 openings, 23 openings, 24 openings, or 25 openings. The openings may be equally or unequal spaced on a portion of the housing and / or arranged in a pattern on a portion of the housing. Additionally, the plurality of openings may have a diameter ranging from about 0.10 mm to about 6.50 mm, including all values ​​and subranges therein. For example, the diameter may be about 0.10 mm, about 0.5 mm, about 1.0 mm, about 1.5 mm, about 2.0 mm, about 2.5 mm, about 3.0 mm, about 3.5 mm, about 4.0 mm, about 4.5 mm, about 5.0 mm, about 5.5 mm, about 6.0 mm, or about 6.5 mm. The multiple openings in the expandable housing may have the same diameter or different diameters. Furthermore, the multiple openings may have any suitable shape, for example, circular, oval, or slot-like. In variations with slots, the slots may be linear, V-shaped, or arcuate in shape. In one variation, the housing includes four openings that are evenly spaced about the center of the housing.

[0102] When the housing includes openings or perforations, the skirt may be coupled to the expandable housing in a manner that covers, surrounds, or otherwise overlies the multiple openings to help generate retrograde blood flow directed toward the patient's head during the pump stroke of the pumping cycle. Retrograde blood flow may help provide proper perfusion of arteries branching from the aortic arch, such as the carotid and subclavian arteries. The ability to maintain proper perfusion of the subclavian artery may prevent backflow from the vertebral basilar artery into the subclavian artery, a phenomenon known as "subclavian steal." The combination of the number of openings and the opening diameter may provide a certain amount of open surface area on the housing for retrograde blood flow. In addition, the skirt may be configured to adjust the amount of open surface area for retrograde flow by adjusting the number of patent (open) and closed openings. In general, a larger amount of open surface area may provide more retrograde blood flow toward the patient's head and heart, and a smaller amount of open surface area may provide more antegrade blood flow to the body. In some variations, a mechanism may be provided to lift, open, or flare the skirt from the exterior of the housing. For example, a tether may be coupled to the skirt, e.g., around the exterior of the skirt, and configured to open and close the skirt relative to the housing, similar to the way a noose can be tightened and loosened. The amount of opening or closing may be adjusted, e.g., using a rotatable dial located on a console external to the patient.

[0103] The skirt may have any suitable shape (e.g., cylindrical or frustoconical) that directs blood back toward the head and heart, and may be coupled to the housing in a variety of ways. In one variation, the skirt may be a separate component from the housing and may be attached to the housing by any suitable means, such as, for example, a friction fit or the use of adhesives. In another variation, the skirt may be integral with the housing (e.g., the two may be integrally formed, such as by molding the two as a single component). The skirt may be made from the same material as the housing. For example, the skirt may comprise a mesh made from stainless steel, titanium, or an alloy thereof (e.g., Nitinol), and a polymer or fabric layer. The length of the skirt may also vary and range from about 0.32 cm (0.125 inches) to about 1.90 cm (0.750 inches).

[0104] The housing may or may not be associated with a cannula, as described further below. With reference to Fig. 33, pump 1700 is shown positioned in descending aorta 1702 above renal arteries 1704. Pump 1700 may include a valve member 1706 within housing 1708 that reciprocates linearly to increase perfusion of kidney 1710. In this variation, housing 1708 may lack a cannula.

[0105] (Cannula) In some variations, the pump may include a cannula with an elongated body, a proximal end, a distal end, and a lumen extending therethrough. The cannula may be coupled to the housing as a separate component or integrally formed as an extension thereof. Depending on the placement of the housing, the cannula may be coupled to or extend from the proximal or distal end of the housing. For example, when the housing resides in the left ventricle, the cannula may extend from the proximal end of the housing such that it traverses the aortic valve and extends into the ascending aorta. In this variation, the cannula may have a smaller diameter than the housing in its expanded configuration, thus aiding in positioning the pump across the aortic valve. In other variations, the pump may include a cannula extending from the distal end of the housing. For example, when the housing resides in the aorta, the cannula may extend from the distal end of the housing such that it traverses the aortic valve and extends into the left ventricle. In further variations, the housing may not have a cannula extending therefrom. In these cases, the housing may reside in any portion of an aorta, such as the thoracic or abdominal aorta, or in a vein, such as the inferior vena cava. The cannula may also be expandable and have an expanded configuration and a collapsed configuration.

[0106] Like the housing, the cannula may include a covering, coating, or layer configured to block the flow of blood. When both the housing and the cannula include a covering, coating, or layer, the length of the covering, coating, or layer may range from about 4.0 cm to about 10 cm, including all values ​​and subranges therein. For example, the covering, coating, or layer may have a length of about 4.0 cm, 4.5 cm, about 5.0 cm, about 5.5 cm, about 6.0 cm, about 6.5 cm, about 7.0 cm, about 7.5 cm, about 8.0 cm, about 8.5 cm, about 9.0 cm, about 9.5 cm, or about 10 cm.

[0107] Cannulas of various lengths may be used. For example, short, medium, or long cannulas may be used. When a short cannula is employed, the length of the cannula may range from about 2.5 cm to about 5.0 cm in its expanded configuration, including all values ​​and subranges therein. For example, the length of a short cannula may be about 2.5 cm, about 3.0 cm, about 3.5 cm, about 4.0 cm, about 4.5 cm, or about 5.0 cm in its expanded configuration. When a medium length cannula is used, the length of the cannula may range from about 25 cm to about 30 cm in its expanded configuration, including all values ​​and subranges therein. For example, the length of a medium cannula may be about 25 cm, about 26 cm, about 27 cm, about 28 cm, about 29 cm, or about 30 cm in its expanded configuration. When a long cannula is used, the length of the cannula may range from 35 cm to about 40 cm in its expanded configuration, including all values ​​and subranges therein. For example, the long cannula may be about 35 cm, about 36 cm, about 37 cm, about 38 cm, about 39 cm, or about 40 cm in its expanded configuration. In some variations, the pump may include each of short, medium, and long cannulas, and the user may select the appropriate cannula based on the desired use of the pump. It should be understood that in some cases, other cannula lengths may also be used. For example, the length of the cannula may range from about 0.5 cm to about 10 cm in its expanded configuration, including all values ​​and subranges therein. For example, the length of the cannula may be about 0.5 cm, about 1.0 cm, about 1.5 cm, about 2.0 cm, about 2.5 cm, about 3.0 cm, about 3.5 cm, about 4.0 cm, about 4.5 cm, about 5.0 cm, about 5.5 cm, about 6.0 cm, about 6.5 cm, about 7.0 cm, about 7.5 cm, about 8.0 cm, about 8.5 cm, about 9.0 cm, about 9.5 cm, or about 10 cm in its expanded configuration. The diameter of the cannula may also range from about 5.0 mm to about 15 mm (including all values ​​and subranges therein) in its expanded configuration.For example, the cannula diameter may be about 5.0 mm, about 6.0 mm, about 7.0 mm, about 8.0 mm, about 9.0 mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, or about 15 mm.

[0108] In some variations, the pump may include a housing chamber having a length of about 3.8 cm and a diameter of about 20 mm in its expanded configuration, and a cannula having a length of about 4.8 cm and a diameter of about 8.0 mm in its expanded configuration. In other variations, the pump may include a housing chamber having a length of about 3.5 cm and a diameter of about 20 mm in its expanded configuration, and a cannula having a length of about 2.2 cm and a diameter of about 8.0 mm in its expanded configuration. In further variations, the pump may include a housing chamber having a length of about 2.8 cm and a diameter of about 20 mm in its expanded configuration, and a cannula having a length of about 1.3 cm and a diameter of about 8.0 mm in its expanded configuration.

[0109] (Coaxial Catheter) As mentioned above, in some variations, the pump may be located outside the body, for example, in a console at the patient's bedside. In these variations, the pump may further comprise a coaxial catheter. A first end of the coaxial catheter may be coupled to the pump housing via a connector or adapter, and an opposite (second) end of the coaxial catheter may be inserted into the patient such that blood flows between the patient and the housing. The coaxial catheter may have an outer diameter of about 10F to about 18F, including all values ​​and subranges therein. For example, the outer diameter of the coaxial catheter may be about 10F, about 11F, about 12F, about 13F, about 14F, about 15F, about 16F, about 17F, or about 18F. The coaxial catheter may include an inflow lumen and an outflow lumen. In some variations, the outflow lumen may be concentrically disposed about the inflow lumen. In other variations, the inflow and outflow lumens may extend parallel to one another within the coaxial catheter. The inflow lumen may generally have an inner diameter of about 7F to about 14F.

[0110] The inflow and / or outflow lumens of the coaxial catheter may be flushed, for example, with sterile saline or heparinized saline. Flushing may be performed at any time, but is generally performed prior to use of the coaxial catheter. Fluids for flushing the coaxial catheter may be introduced into one or more of the catheter lumens by various types of connectors, for example, Y-connectors or two- or three-way connectors. Other types of catheter connectors and fittings may also be used. Flushing around the coaxial catheter site may also be performed around the site of insertion into the body.

[0111] (Valve cone) The linearly reciprocating member of the pumps described herein may include a valve member, such as a valve cone. The valve cone may include multiple layers of material disposed within the expandable housing and coupled to a support member. The support member may be an expandable frame. However, in some variations, a single layer of material may be coupled to the support member. As mentioned above, the valve cone may have an inlet side facing the inlet of the expandable housing and an outlet side facing the outlet of the expandable housing. The multiple layers of material may include a mesh layer, a flow control layer, or a combination thereof. Any number of layers of material may be used, so long as at least one flow control layer is included. The flow control layer generally includes multiple flaps that open when blood is drawn into the expandable housing during a filling stroke and close when blood is moved out of the expandable housing during a pump stroke. The mesh layer may be disposed between the flow control layer and the expandable frame and used to support the flow control layer so that the flaps are not pushed or bent through the openings in the expandable frame when pressure against the flaps is applied during the pump stroke. Thus, the mesh layer may help to maintain the flaps in a closed configuration during the pump stroke when blood is moved out of the housing through the housing outlet. However, during the fill stroke, the mesh layer allows blood to flow from the housing inlet through the holes in the mesh and then through the flaps, transitioning them to their open configuration so that blood can move to the outlet side of the valve cone.

[0112] Woven fabrics or elastomeric polymers may be used to form the mesh layer. Exemplary elastomeric polymers include, but are not limited to, silicone, polyester, polyurethane, fluoropolymer, or combinations thereof. The thickness of the mesh layer may range from about 0.03 mm to about 0.05 mm, including all values ​​and subranges therein. The size and shape of the mesh openings may also vary and may depend on the size and shape of the flaps in the flow control layer given their support function, as explained above. In terms of shape, the mesh openings may be circular, triangular, square, rectangular, diamond-shaped, or the like.

[0113] The material layer may be coupled to the expandable frame in any suitable manner, for example, by sewing, stitching, or suturing, by use of adhesive, by heat sealing, or by welding. The material layer may be coupled to the expandable frame at multiple attachment points on the frame. The expandable frame may have an expanded configuration and a collapsed configuration and may include stainless steel, nickel, titanium, or alloys thereof (e.g., Nitinol). In one variation, the expandable frame is made from laser cut Nitinol tubing. The expandable frame may have a first end that connects to the actuator of the pump and a shaped second end that connects to the material layer of the valve cone. In general, the shape of the valve cone corresponds to the shape of the expandable frame. The expandable frame typically has a conical shape, but any shape that can be collapsed to allow advancement through a cannula may be used. When the expandable frame is shaped into a cone, the multiple material layers (e.g., mesh and flow control layers) may also be shaped into a cone.

[0114] The flow control layer of the valve cone may also be formed from various polymers, such as elastomeric polymers as described above, or from Mylar® plastic film. The flow control layer may include a plurality of flaps having an open configuration and a closed configuration. Generally, the plurality of flaps are in an open configuration during the filling stroke and in a closed configuration during the pumping stroke. The flow control layer may be cut to generate a plurality of flaps, which may be of any suitable size and shape that allows blood to flow into the housing during the filling stroke. For example, the flaps may have a semicircular, arc, circular, triangular, diamond, square, or rectangular shape. Any suitable number of flaps in the flow control layer may also be employed. The number of flaps may range from 2 to 20. For example, 2 flaps, 3 flaps, 4 flaps, 5 flaps, 6 flaps, 7 flaps, 8 flaps, 9 flaps, 10 flaps, 11 flaps, 12 flaps, 13 flaps, 14 flaps, 15 flaps, 16 flaps, 17 flaps, 18 flaps, 19 flaps, or 20 flaps may be included. In one variation, a flow control layer including 15 flaps may be useful. The valve cone may be configured such that a greater number of flaps are included when they are smaller in size and fewer flaps are included when they are larger in size. When the flaps are semicircular in shape, they may have a radius ranging from about 0.50 mm to about 3.0 mm, including all values ​​and subranges therein.

[0115] When the cone valve is molded into a cone, the flow control layer is also generally molded into a cone. Here, the material of the flow control layer may first be provided as a circle with a center cutout and slits extending from the cutout to the periphery of the circle (see, e.g., 28A). The slits provide free edges so that the layer can later be rolled to form the cone shape. Flaps may then be formed by laser cutting or stamping the flap shapes into the flow control layer. The flaps may have any suitable size and shape, as described above. In one variation, a perimeter is then created around the perimeter of the circle by rolling the edge of the flow control layer onto itself to create a thickness at the perimeter, and sewing, heat sealing, gluing, etc. the rolled edge to maintain the thickness in that area. In another variation, the edge may be rolled over an O-ring to form the perimeter. In a further variation, the rim is a separate component from the flow control layer and includes an O-ring that is sewn, heat sealed, glued, bonded, etc. to the edge of the flow control layer. After the rim is formed, the free edge of the circular flow control layer is rolled to form it into a cone. The rim may help create a seal between the rim of the flow control cone and the inner surface of the housing during the pump stroke. A cone-shaped shaped mesh layer may be formed by the same process, except that a rim need not be included.

[0116] In addition to the rim, the flow control layer may include a body. The body and rim may be made from the same material or from different materials. Additionally, the body and rim may be separate components or may be integrally formed with one another. When provided as separate components, the body may be formed from an elastomeric polymer or from a Mylar® plastic film, and the rim may be an O-ring. The peripheral edge of the flow control layer may be wrapped over the O-ring to form the rim. The thickness of the rim may exceed the thickness of the body. The body may have a thickness ranging from about 0.03 mm to about 0.05 mm, including all values ​​and subranges therein. The rim may have a thickness ranging from about 0.20 mm to about 1.5 mm, including all values ​​and subranges therein. For example, the rim may have a thickness of about 0.20 mm, about 0.30 mm, about 0.40 mm, about 0.50 mm, about 0.60 mm, about 0.70 mm, about 0.80 mm, about 0.90 mm, about 1.0 mm, about 1.1 mm, about 1.2 mm, about 1.3 mm, about 1.4 mm, or about 1.5 mm.

[0117] (flexible diaphragm) In some variations, the linearly reciprocating member of the pumps described herein may include a flexible diaphragm as a valve member. The flexible diaphragm may be contained within a housing. The flexible diaphragm may have a collapsed configuration and an extended configuration, and may linearly reciprocate within the housing. In the collapsed configuration, the flexible diaphragm may have a smaller diameter than when in the extended configuration to allow advancement through the vessel. Once at the target location within the patient, the flexible diaphragm may be deformed to its extended configuration and move blood from the inlet of the housing, through the body of the housing, to the outlet of the housing, and through it, generating the pressure required to pump the blood. The flexible diaphragm may be coupled to a support member, which in turn is coupled to an actuator that linearly reciprocates the flexible diaphragm within the housing. The support member may be a conically shaped expandable frame (shown in FIG. 34) or a tine support, as further described below. The coupling to the expandable frame may be accomplished in any suitable manner, for example, by sewing, stitching, or suturing, by use of adhesives, by heat sealing, or by welding. The flexible diaphragm may include a diaphragm body and a periphery. In some variations, the flexible diaphragm may include an elastomeric polymer. Non-limiting examples of elastomeric polymers include, but are not limited to, silicone, polyester, polyurethane elastomers, fluoropolymers, or combinations thereof. Some variations of the flexible diaphragm include polytetrafluoroethylene (PTFE) as the elastomeric polymer. The body and periphery of the flexible diaphragm may include the same material or different materials. In some cases, the diaphragm body and periphery are integrally formed.

[0118] The material and / or thickness of the diaphragm body and rim may be selected such that the flexible diaphragm can flex during the filling stroke and allow blood to flow around it, but is sufficiently elastic to prevent the flexible diaphragm from everting or folding during the pumping stroke. Additionally, the material and / or thickness of the flexible diaphragm may be sufficiently rigid so that the pressure required to effect the pumping stroke is generated and to prevent stretching of the diaphragm body. In one variation, the flexible diaphragm may maintain its shape during the pumping cycle by including a rim that is thicker than the diaphragm body.

[0119] In some variations, the thickness of the diaphragm body may range from about 0.03 mm to about 0.3 mm, including all values ​​and subranges therein. For example, the diaphragm thickness may be about 0.03 mm, about 0.04 mm, about 0.05 mm, about 0.06 mm, about 0.07 mm, about 0.08 mm, about 0.09 mm, about 0.10 mm, about 0.20 mm, or about 0.30 mm. With respect to the periphery of the diaphragm, the thickness may range from about 0.20 mm to about 1.5 mm, including all values ​​and subranges therein. For example, the rim thickness may be about 0.20 mm, about 0.30 mm, about 0.40 mm, about 0.50 mm, about 0.60 mm, about 0.70 mm, about 0.80 mm, about 0.90 mm, about 1.0 mm, about 1.1 mm, about 1.2 mm, about 1.3 mm, about 1.4 mm, or about 1.5 mm. In some variations, the rim thickness may range from about 0.5 mm to about 1.0 mm (including all values ​​and subranges therein). The thickness of the rim may exceed the thickness of the diaphragm body, which may help the flexible diaphragm maintain its shape during a pumping cycle, as mentioned above. A larger rim thickness may also help create a seal between the rim and the inner surface of the housing during a pump stroke. However, in some variations, the rim and the body may have equal thickness. The thickness ratio between the diaphragm body and the rim may range from about 1:5 to about 1:20. The periphery of the flexible diaphragm may have a width ranging from about 1.0 mm to about 2.0 mm, including all values ​​and subranges therein. In one variation, the diaphragm body may have a thickness of about 0.05 mm and the periphery may have a thickness of about 0.25 mm.

[0120] Further, the flexible diaphragm may have any suitable shape or geometry capable of creating a seal between the periphery of the diaphragm and the inner surface of the housing during the pump stroke. For example, the flexible diaphragm may have a conical, frustoconical, or hemispherical shape when in the extended configuration. The flexible diaphragm may also include ribs, which may help provide additional stiffness to the flexible diaphragm body. In one variation, the flexible diaphragm has a conical shape and ribs that help maintain the conical shape during the pump stroke. The ribs may be integrally formed with the diaphragm body or they may be separate components that are coupled to the diaphragm body, for example, by the use of adhesives, welding, etc. In some variations, the ribs may extend from a central portion of the diaphragm body to the periphery. The ribs may have a rib angle between a longitudinal axis of the ribbed rib and an axis perpendicular to the actuator ranging from about 30 degrees to about 60 degrees, including all values ​​and subranges therein. For example, the rib angle may be about 30 degrees, about 35 degrees, about 40 degrees, about 45 degrees, about 50 degrees, about 55 degrees, or about 60 degrees. The ribs may be equally spaced from one another. In some variations, the ribs may have unequal spacing from one another.

[0121] (Actuator / Controller) The pumps described herein may include an actuator, typically coupled to a valve member via a support member. The valve member may be a flexible diaphragm or valve cone. The actuator may generally be configured to linearly reciprocate the flexible diaphragm or valve cone within a housing to generate the fill stroke and pump stroke of a pumping cycle. Exemplary actuators may include, but are not limited to, cables, wires, rods, or other actuators having the flexibility to track over guidewires and navigate vessels, and the stiffness required to reciprocate the flexible diaphragm during pump and fill cycles. The linear reciprocating movement of the actuator may be generated by a linear motor drive and a linear motor controller. Although the linear motor is typically mounted external to the patient, in some variations the linear motor may be provided as part of a pump that is implanted within the patient, for example, within a subcutaneous pocket or placed within the patient's heart or vessels.

[0122] The linear motor controller may adjust various parameters of the pumping cycle. For example, the linear motor controller may adjust the speed of the linear reciprocating motion of the actuator and the flexible diaphragm and the length of the pump and fill stroke. The speed of the linear reciprocating motion may be adjusted by increasing or decreasing the number of pumping cycles per minute. In some variations, the number of pumping cycles per minute may be preset or adjusted to a rate corresponding to the patient's natural cardiac pumping cycle. In other variations, patient parameters such as blood pressure (e.g., left ventricular pressure, left ventricular end diastolic pressure, aortic pressure, and / or systemic blood pressure) may be preset to a target value or range, and the pumping cycle parameters may be adjusted to meet the preset blood pressure value or range. The preset targets for blood pressure and pumping cycles per minute may be based on factors such as the patient's age, height, or weight, or any combination of these factors. The type of heart failure the patient is diagnosed with (e.g., systolic heart failure, diastolic heart failure, right heart failure, left heart failure) may also be a factor when establishing pumping cycles per minute and blood pressure target values.

[0123] In some variations, adjustment or control of pump or patient parameters (e.g., left ventricular pressure, left ventricular end-diastolic pressure, aortic pressure, and / or systemic blood pressure) may be accomplished manually, e.g., by one or more control features or buttons provided on a user interface of an external console. In other variations, pump parameters may be adjusted automatically, e.g., using a closed-loop system. A closed-loop system may comprise a processor and instructions stored in a memory of the processor. During operation of the pump, the processor may store and / or process data from the pump and / or the patient, execute instructions from the memory, and automatically adjust pump parameters based on data received from one or more sensors provided with the pump. For example, the rate of the pumping cycle may be automatically adjusted (i.e., increased or decreased) such that a preset blood pressure is met, as described above.

[0124] Various types of sensors may be employed to measure pump parameters (e.g., pump cycles per minute) and patient parameters (e.g., blood pressure and blood flow rate). Non-limiting examples of sensors include pressure sensors, flow sensors, temperature sensors, heart rate sensors, and heart rhythm sensors. Pressure sensors may be placed at various pump locations. In some variations, one or more pressure sensors may be mounted in or on the blood flow inlet or inlet / inflow tubing, and one or more pressure sensors may be mounted in or on the blood flow outlet, outlet / outflow tubing, or skirt of the pump. In other variations, two pressure sensors may be mounted in or on the inlet and outlet for redundancy in case one inlet and / or outlet pressure sensor fails. In further variations, one or more pressure sensors may be mounted near the blood flow inlet or inlet / inflow tubing, and one or more pressure sensors may be mounted near the blood flow outlet, outlet / outflow tubing, or skirt of the pump. The pressure sensors may be communicatively coupled to the controller such that the controller may receive measurements from the pressure sensors and utilize those measurements to modify pump parameters, as described above. For example, in some variations, the controller may be configured to have a predetermined high blood pressure set point, a low blood pressure set point, and / or a predetermined target blood pressure range. The controller may further be configured to compare measurements received from one or more of the pressure sensors to the high blood pressure set point, the low blood pressure set point, and / or a predetermined desired blood pressure range, and modify one or more pump parameters (e.g., the speed of reciprocating motion) accordingly. For example, when measurements from the pressure sensors indicate that the patient's measured blood pressure has fallen below the low set point and / or falls below the desired range, the controller may increase the speed of the linear reciprocating motion.When measurements from the pressure sensor indicate that the patient's measured blood pressure has risen above the high blood pressure set point and / or above the desired range, the controller may decrease the speed of the linear reciprocating motion, thereby reducing the flow and bringing the blood pressure back below the high set point and / or back within the target range.

[0125] (Tyne) Some variations of the pumps described herein may also include a tine support as a support member. The tine support may include a base and a plurality of tines configured to support the flexible diaphragm in an extended configuration during a pump stroke. In other variations, the tine support may be coupled to the flexible diaphragm, as further described below in Figures 5-7. The plurality of tines may be flexible and / or elastic and may have an expanded configuration and a compressed configuration. In the compressed configuration, the plurality of tines may have a smaller diameter than when in the extended configuration to allow advancement through the vessel. Once at the target location within the patient, the plurality of tines may be expanded to a larger diameter. Additionally, the plurality of tines may have an expanded configuration during the pump stroke of a linear pumping cycle and a compressed or partially compressed configuration during a filling stroke. The plurality of tines may be coupled to an actuator. In one variation, the plurality of tines may each extend from a common hub or base to a free end. The hub may be configured to couple to the actuator. Additionally, the free ends of the tines may extend or flex outwardly as the tines move from the compressed configuration to the expanded configuration.

[0126] The number of tines included in the plurality of tines may range from about 2 to about 8. For example, the plurality of tines may include two (2) tines, three (3) tines, four (4) tines, five (5) tines, six (6) tines, seven (7) tines, or eight (8) tines. In one variation, the plurality of tines includes six (6) tines. The plurality of tines may be equally spaced or unequal spaced from one another. With respect to materials, the plurality of tines may be made from a metal, such as stainless steel, titanium, or alloys thereof, or a biocompatible polymer, such as a fluoropolymer, polyamide, polyetheretherketone (PEEK), polyimide, polyolefin, polyurethane, or combinations thereof.

[0127] In one variation, the plurality of tines may include a metal strip. The metal strip may extend from a common base at one end. At the other end, each tine of the plurality of tines has a free end. The free end may be attached to a sleeve, e.g., a short cylinder, by welding, soldering, or gluing. The sleeve provides additional support area for the flexible diaphragm to bear against during the pump stroke and may help prevent movement of the flexible diaphragm between the tines during the pump stroke. In one variation, the length of each sleeve is about 1.0 mm. The tines may be made from a metal cylinder that is laser cut to form the strip.

[0128] Instead of strips, the multiple tines may include multiple flexible first wires. Any suitable number of first wires may be employed. For example, four (4), six (6), eight (8), ten (10), or twelve (12) wires may be used. A number of holes corresponding to the number of first wires may be drilled into the base so that one end of the wire may be inserted into the hole. At the other end (free end) of the wire, a sleeve may be attached in the same manner as described above. The sleeve may include a central hole through which the second wire is threaded. After all sleeves are threaded through, the end of the second wire may be joined by soldering, welding, gluing, and the like. The second wire may be made of a variety of materials, including, but not limited to, stainless steel, spring steel (piano wire), or Nitinol. In some variations, each tine of the plurality of tines may include two wires attached at their free ends to the same barrel. Thus, when the plurality of tines includes six (6) tines, the number of wires would be twelve (12). The second wire may provide additional flexible diaphragm support during the pump stroke to that provided by the barrel, such that movement of the flexible diaphragm between the tines during the pump stroke is prevented or minimized.

[0129] (umbrella structure) In some variations, a pump for assisting blood circulation may include a housing having an inner surface and an expanded configuration, and a valve member having an umbrella structure disposed within the expandable housing. The umbrella structure may include a membrane having a body and a periphery, a frame including a plurality of struts, and an anchor, and may have an expanded configuration and a collapsed configuration. An actuator coupled to the umbrella structure may be configured to linearly reciprocate the umbrella structure within the housing. During the pumping stroke and the filling stroke of the pump, the periphery of the membrane may be configured to maintain contact with the inner surface of the housing. In some variations, the contact may be maintained for the entire duration of the pump stroke. In other variations, the contact may be maintained for a portion of the pump stroke as long as sufficient pressure is generated to move a desired amount of blood out of the housing during the pump stroke. In further variations, for example, when a high pump speed is required, the umbrella structure may be configured such that there is a slight play or gap between the periphery and the inner surface of the housing. The gap may help to avoid creating excessive friction within the pump. The gap may also be sized such that adequate pressure may be generated over the pump stroke while also avoiding crushing or damaging the red blood cells during the pump stroke, where the diameter of the umbrella structures in their expanded configuration may be at least about 95 percent of the diameter of the housing in their expanded configuration. For example, the umbrella structures in their expanded configuration may be at least about 95 percent, at least about 96 percent, at least about 97 percent, at least about 98 percent, or at least about 99 percent of the diameter of the housing in their expanded configuration.

[0130] The membrane of the umbrella structure may be bonded to the plurality of struts and completely or partially cover the struts. The membrane may comprise an elastomeric polymer. Non-limiting examples of elastomeric polymers include silicone, polyester, polyurethane, fluoropolymer, or combinations thereof. Fluoropolymers that may be employed include polytetrafluoroethylene (PTFE) or expanded polytetrafluoroethylene (ePTFE). In some variations, the umbrella structure may comprise a plurality of struts and a PTFE or ePTFE membrane coated on the struts. The membrane may cover the entire struts or a portion thereof, as mentioned above. In some variations, the membrane may cover a length of the struts ranging from about 0.5 cm to about 3.0 cm, including all values ​​and subranges therein. For example, the length of the covering may be about 0.5 cm, about 1.0 cm, about 1.5 cm, about 2.0 cm, about 2.5 cm, or about 3.0 cm. The body and periphery of the membrane may comprise the same or different materials. In some cases, the membrane body and periphery are integrally formed. The thickness of the membrane body may range from about 0.03 mm to about 0.3 mm. With respect to the membrane periphery, the thickness may range from about 0.70 mm to about 1.5 mm. The thickness of the periphery may be greater than the thickness of the membrane body. However, in some variations, the periphery and the body may have equal thicknesses.

[0131] The umbrella structure may comprise a frame including any suitable number of struts. The number of struts may range from 3 to 10, including all values ​​and subranges therein. For example, the number of struts may be 3, 4, 5, 6, 7, 8, 9, or 10. In one variation, the umbrella structure comprises six struts. In another variation, the umbrella structure comprises ten struts. A plurality of struts may support the membrane, and the struts may be made from stainless steel, nickel, titanium, or alloys thereof (e.g., Nitinol). In one variation, the struts are made from laser cut Nitinol tubing.

[0132] The struts may have any suitable shape or geometry. The struts may have one or more sections, and the one or more sections may have any suitable shape or geometry. The cross-sectional shape of the struts may be circular, oval, triangular, square, or rectangular. The struts may have different cross-sectional shapes along their length. For example, the struts may have one or more sections with a first cross-sectional shape (e.g., circular) and one or more sections with a second cross-sectional shape (e.g., rectangular). In some cases, the struts may include three sections, i.e., two end sections and a middle section therebetween. The end sections may have a circular cross-sectional shape and the middle section may have a rectangular cross-sectional shape. The rectangular cross-sectional shape may provide the middle section with a flattened profile. In some variations, different sections of the struts may have different widths. For example, when a strut includes three sections (two end and one middle section), the middle section may be wider than one or both of the two end sections. In other variations, different sections of the strut may have different thicknesses. For example, one or both end sections may have a thickness that exceeds the middle section (the middle section is flatter than one or both end sections).

[0133] The distal tip of the strut may be configured to be atraumatic. In one variation, the atraumatic distal tip may be shaped to help prevent the strut from damaging the inner surface of the housing during the pump stroke. For example, the atraumatic distal tip may have a rounded or oval shape. Additionally or alternatively, one or more slits or cutouts may be provided along the length of the strut to increase strut flexibility, which may help prevent the strut from damaging the inner surface of the housing during the pump stroke. In some variations, the distal tip may include an opening that allows blood flow therethrough. The opening may have various sizes and shapes, which may depend on the size and shape of the distal end. For example, the opening may be shaped to be circular, oval, square, rectangular, triangular, etc. In one variation, the opening at the distal tip is rectangular in shape. In another variation, the opening at the distal tip is circular in shape. Radiopaque markers may also be provided at any suitable location along the length of one or more struts, for example, at the distal end of one or more struts (e.g., one-third of the struts, half of the struts, all of the struts). In some variations, the umbrella structure may include a bend and an opening in one or more of the struts. In some variations, the inclusion of both of these features may help minimize the risk of the strut puncturing the housing during a pump stroke.

[0134] The length of the struts may range from about 1.0 cm to about 3.0 cm, including all values ​​and subranges therein. For example, the struts may have a length of about 1.0 cm, about 1.1 cm, about 1.2 cm, about 1.3 cm, about 1.4 cm, about 1.5 cm, about 1.6 cm, about 1.7 cm, about 1.8 cm, about 1.9 cm, about 2.0 cm, about 2.1 cm, about 2.2 cm, about 2.3 cm, about 2.4 cm, about 2.5 cm, about 2.6 cm, about 2.7 cm, about 2.8 cm, about 2.9 cm, or about 3.0 cm. In some variations, e.g., variations having struts of longer length, the struts may extend beyond the periphery of the membrane. In other variations, the struts may not extend beyond the periphery and may instead be completely covered by the membrane.

[0135] As mentioned above, in some variations, one or more of the struts may include one or more bends or curves along their length. The one or more bends may be provided anywhere along the strut. For example, the one or more bends may be provided at the distal (free) ends of the struts and / or at the midpoints of the struts. The bend region of the struts may have a variety of lengths. For example, the length of the bend region may range from about 0.2 cm to about 1.0 cm (including all values ​​and subranges therein). For example, the bend region may have a length of about 0.2 cm, about 0.3 cm, about 0.4 cm, about 0.5 cm, about 0.6 cm, about 0.7 cm, about 0.8 cm, about 0.9 cm, or about 1.0 cm.

[0136] The bends in the struts may form a bend angle of about 5 degrees to about 15 degrees (including all values ​​and subranges therein) relative to the longitudinal axis of the umbrella structure. For example, the bend angle may be about 5 degrees, about 6 degrees, about 7 degrees, about 8 degrees, about 9 degrees, about 10 degrees, about 11 degrees, about 12 degrees, about 13 degrees, about 14 degrees, or about 15 degrees. In addition to a rounded, atraumatic distal tip, the bends may be employed to prevent the struts from puncturing or otherwise damaging the inner surface of the housing during a pump stroke.

[0137] The umbrella structure may further include an anchor having a proximal end and a distal end. The proximal end of the anchor may be configured to attach the strut to a linear actuator of the pump. The distal end of the anchor may be configured to attach to the plurality of struts. In some variations, the anchor and the strut are integrally formed by laser cutting from a Nitinol tube. The anchor length may range from about 0.5 cm to about 1.5 cm, including all values ​​and subranges therein. For example, the anchor length may be about 0.5 cm, about 0.6 cm, about 0.7 cm, about 0.8 cm, about 0.9 cm, about 1.0 cm, or about 1.5 cm. The umbrella structure in some cases may include components that facilitate collapse of the strut during the filling stroke of the pumping cycle. For example, the strut may be attached to the proximal or distal end of the anchor via a hinge, pivot, joint, or other pivoting mechanism that increases the flexibility of the strut at that point. Exemplary types of hinges may include, but are not limited to, butt hinges, non-recessed hinges, pivot hinges, and bi-fold hinges, which would be sized according to the width and / or length of the strut. Flexible connectors may also be used to join the strut to the anchor. The flexible connector may include a polymer or a polymer with fiber reinforcement. The polymer may include a thermoplastic elastomer, such as a styrenic block copolymer, a thermoplastic polyolefin, a thermoplastic polyurethane, a thermoplastic polyamide, or a thermoplastic copolyester. All of the struts or some of the multiple struts may be attached to the anchor by a pivot mechanism or a flexible connector.

[0138] When the umbrella structure is in its expanded configuration, the plurality of struts may extend radially from the distal end of the anchor to generate a strut angle relative to a longitudinal axis of the umbrella structure. The strut angle may depend, in part, on the strut length and may range from about 30 degrees to about 60 degrees, including all values ​​and subranges therein. For example, the strut angle may be about 30 degrees, about 35 degrees, about 40 degrees, about 45 degrees, about 50 degrees, about 55 degrees, or about 60 degrees.

[0139] Instead of extending radially from the anchor, the struts may be configured to invert (e.g., fold back) about the anchor, forming, for example, a conical shape. In such a configuration, the struts may be attached to a proximal end of the anchor. In contrast, when the struts extend radially from the anchor, the anchor may generally be attached to a distal end of the anchor. The membrane may also fully or partially cover the inverted struts.

[0140] In some variations, for example when longer struts are employed, the struts may form a cage structure. The struts of the cage may be fixed or tethered to the linear actuator at one end and slidable over the linear actuator at the other end. In this configuration, as shown in FIG. 38, the cage expands to an expanded configuration during the pump stroke of the pumping cycle and collapses to a collapsed configuration during the filling stroke. With reference to FIG. 38, the plurality of struts 2200 may include a proximal end 2202, a distal end 2204, and a middle section 2206. When the cage 2208 is in the expanded configuration (as shown in FIG. 38), the middle section 2206 of the struts 2200 may be flat and may form a flattened region of the cage 2208. The proximal end 2202 of the struts 2200 may be fixedly attached to the linear actuator (not shown). Distal end 2204 is not attached to a linear actuator and therefore may slide along the linear actuator during reciprocation of cage 2208. A membrane (not shown) may be coupled to cage 2208 and cover any suitable length of strut 2200 that allows a pump stroke to be generated.

[0141] Any component of the pumps described herein may be coated. For example, one or more of the cannula, expandable housing, expandable frame, and flexible diaphragm may be coated. One or more tines or one or more struts may also be coated. Pump components may be fully or partially coated. The coating may provide increased lubricity and / or wettability to the portion of the pump that is coated, or may provide anti-fouling, anti-proliferative, or anti-bacterial properties to the coated pump component.

[0142] The thickness of the coating may vary depending on the pump component being coated. In some variations, when the expandable housing includes a coating, the coating thickness may range from about 0.0025 cm to about 0.010 cm (about 0.001 inch to about 0.004 inch), including all values ​​and subranges therein. For example, the coating thickness may be about 0.0025 cm, about 0.003 cm, about 0.004 cm, about 0.005 cm, about 0.006 cm, about 0.007 cm, about 0.008 cm, about 0.009 cm, or about 0.010 cm. When the flexible diaphragm is coated, the coating thickness may range from about 0.0013 cm to about 0.0025 cm (about 0.0005 inch to about 0.001 inch), including all values ​​and subranges therein. For example, the coating thickness may be about 0.0013 cm, about 0.0015 cm, about 0.0020 cm, or about 0.0025 cm.

[0143] The coating may generally comprise a polymeric material. Exemplary polymeric materials may include, but are not limited to, hydrophilic polymers, hydrophobic polymers, or a mixture of these two types of polymers. The coating may be a single layer on the pump component, or may comprise multiple layers. When multiple layers are employed, each layer may be made from the same polymer or from different polymers.

[0144] Examples of hydrophilic polymers that may be used to form the coating include, but are not limited to, polyurethanes, including polyether polyurethanes, polyester polyurethanes, polyurethane ureas, and copolymers thereof, polyvinylpyrrolidones, polyvinyl alcohols, polyethylene glycols and their copolymers, polypropylene glycols and their copolymers, polyoxyethylenes and their copolymers, polyacrylic acid, polyacrylamides, carboxymethylcellulose, cellulose and its derivatives, dextran and other polysaccharides, starch, guar, xantham and other gums and thickeners, collagen, gelatin, and other biological polymers.

[0145] Examples of hydrophobic polymers that may be used to form the coating include, but are not limited to, fluoropolymers such as polytetrafluoroethylene (PTFE) and expanded polytetrafluoroethylene (ePTFE), polyvinyl chloride (PVC), polyvinyl acetate, poly(ethylene terephthalate), silicone, polyester, polyamide, polyurea, styrene-block copolymers, polymethyl methacrylate, acrylic-butadiene-styrene copolymers, polyethylene, polystyrene, polypropylene, natural and synthetic rubber, acrylonitrile rubber, and mixtures and copolymers of any of the foregoing. In one variation, the coating includes polytetrafluoroethylene (PTFE) as the polymeric material. In another variation, the coating includes expanded polytetrafluoroethylene (ePTFE) as the polymeric material.

[0146] (Pump system) A system for pumping blood is also described herein. The system may generally include a pump, the pump comprising an expandable housing having an inner surface and an expanded configuration. A valve, including a periphery, may be disposed within the expandable housing and may have an expanded or extended configuration and a collapsed configuration. The pump may also include an actuator coupled to the valve and linearly reciprocating the valve within the housing to generate a pump stroke and a fill stroke of a pumping cycle. During the pump stroke, the periphery of the valve member may be configured to maintain contact with the inner surface of the housing. In some variations, the contact may be maintained for the entire duration of the pump stroke. In other variations, the contact may be maintained for a portion of the pump stroke as long as sufficient pressure is generated to move a desired amount of blood out of the housing during the pump stroke. In further variations, for example, when high pump speeds are required, the valve member may be configured such that there is a slight clearance or gap between the periphery and the inner surface of the housing. The clearance may help to avoid creating excessive friction within the pump. The gap may also be sized such that the proper pressure may be generated over the pump stroke while also avoiding crushing or damaging the red blood cells during the pump stroke, where the diameter of the valve members in their extended or expanded configuration may be at least about 95 percent of the diameter of the housing in its expanded configuration, for example, the valve members in their extended or expanded configuration may be at least about 95 percent, at least about 96 percent, at least about 97 percent, at least about 98 percent, or at least about 99 percent of the diameter of the housing in its expanded configuration.

[0147] In addition, the system may include a console, external to the patient, containing a controller configured to adjust the actuator. A user interface may be coupled to the controller and configured to manually set or adjust pump or patient parameters and / or display pump and patient parameters. The user interface may be a display forming part of the console that houses the linear actuator. The console may be a stationary component of the system or a mobile component when coupled to a wheeled cart or other rolling base.

[0148] Exemplary pump parameters include, but are not limited to, pump cycles per minute and pump cycle duration. When setting or adjusting the pump cycle duration, the duration of either the fill stroke or the pump stroke may be set or adjusted. Non-limiting examples of patient parameters include age, height, weight, left ventricular pressure, left ventricular end diastolic pressure, aortic pressure, and systemic blood pressure.

[0149] 32A, an exemplary console 1600 is shown coupled to a mobile base 1602. The controller 1600 may be removably coupled to the mobile base 1602 and may be lifted from the base 1602 when desired. In addition, the mobile base 1602 may include a handle 1604 and a storage compartment 1606 for holding pump components. The console 1600 may include an area 1608 for accessing and connecting drive lines / cables. A user interface 1610, including a display 1612, may also be provided on the console 1600. The display 1612 may show various pump and patient parameters and may include a touch screen and / or buttons (e.g., touch sensitive buttons). For example, as shown in FIG. 32B, pump parameters such as cycles per minute (CPM) (also referred to herein as pump cycles per minute), total number of pump cycles, and pump activation time are displayed. Patient parameters such as blood flow, left ventricular pressure, aortic pressure, and blood pressure may also be displayed. Touch-sensitive buttons 1614 may be used to manually set or adjust, e.g., increase or decrease, the pump cycles per minute. Audible and / or visual alerts may be issued when any pump or patient parameter rises above or falls below a preset value or falls above or below a preset range of values.

[0150] In use, the pump of the system may be advanced to a target location within the patient's circulatory system. The pump may comprise an expandable housing, including an inner surface, an expanded configuration, and a collapsed configuration, and a valve member with a periphery disposed within the expandable housing, as described above. Once at the target location, the expandable housing may be expanded from the collapsed configuration to the expanded configuration. Pump parameters and / or patient parameters may be determined, and the valve member may be linearly reciprocated within the expandable housing according to those parameters to generate a filling stroke and a pump stroke. During the pump stroke, contact between the periphery of the valve member and the inner surface of the expandable housing may be maintained. In some variations, the valve member may be configured not to contact the inner surface of the housing, as mentioned above, with a slight play or gap between the periphery and the inner surface of the housing. Also, as mentioned above, the pump parameters may include pump cycles per minute, duration of the pump cycle, or both. When setting or adjusting the duration of the pump cycle, the duration of either the filling stroke or the pump stroke may be set or adjusted, or both may be set or adjusted. When pump parameters are determined, they may be based on patient parameters such as age, height, weight, left ventricular pressure, left ventricular end diastolic pressure, aortic pressure, or systemic blood pressure.

[0151] The pump and patient parameters may be displayed on a user interface. The parameters may be continuously or intermittently monitored and the measurements may be continuously or intermittently displayed on the user interface. The user interface may be a display forming part of a console that houses the linear actuator. The console may be a stationary component of the system, as mentioned above, or a mobile component when coupled to a wheeled cart or other rolling base. The pump and patient parameters may be manually adjusted via buttons on the user interface. In some cases, the display of the user interface includes touch-sensitive buttons for manually adjusting the parameters. In other cases, the pump parameters may be automatically adjusted based on the patient parameters. The automatic adjustment may be accomplished by a controller.

[0152] The pump of the system may be advanced to a target location within an artery. When the artery is the aorta, the target location may be the ascending aorta, the aortic arch, the thoracic aorta, the descending aorta, or the abdominal aorta. The pump may also be advanced to a target location within a vein. The vein may be the inferior vena cava. When advanced within the inferior vena cava, the target location may reside between the hepatic vein and the right atrium. In this location, the pump may increase circulation from the liver or from the lower extremities. Another target location for the pump may be above or below the renal vein.

[0153] When the pumps are positioned such that they traverse the aortic valve, the length of the pumps below the aortic valve (and within the left ventricle) may range from about 4.0 cm to about 10 cm, including all values ​​and subranges therein. For example, the length of the pump below the aortic valve may be about 4.0 cm, about 4.5 cm, about 5.0 cm, about 5.5 cm, about 6.0 cm, about 6.5 cm, about 7.0 cm, about 7.5 cm, about 8.0 cm, about 8.5 cm, about 9.0 cm, or about 10 cm. These lengths may include the length of all or a portion of the housing chamber and associated cannula. The total pump length from the distal tip of the device to the proximal end of the associated cannula may range from about 5.0 cm to about 14 cm, including all values ​​and subranges therein. For example, the total pump length may be about 5.0 cm, about 5.5 cm, about 6.0 cm, about 6.5 cm, about 7.0 cm, about 7.5 cm, about 8.0 cm, about 8.5 cm, about 9.0 cm, about 9.5 cm, about 10 cm, about 10.5 cm, about 11 cm, about 11.5 cm, about 12 cm, about 12.5 cm, about 13 cm, about 13.5 cm, or about 14 cm.

[0154] (Additional Exemplary Variations) An exemplary pump is shown in FIG. 1. As shown therein, pump 10 includes an elongated outer sheath 11 having an inner end 12 that supports a bearing 13. An expandable housing 25 (seen in more detail in FIG. 3) is received within the interior of outer sheath 11 and holds bearing 13 in a fixed attachment. An inner sheath 16 extends from bearing 13 through the interior of outer sheath 11. A tine support 15 having a plurality of tines 20 for supporting a flexible diaphragm 30 is disposed within inner sheath 16 in a collapsed configuration. An actuator (drive cable) 40 is coupled at one end to tine support 15 by a fixed attachment, extends through the interior of inner sheath 16, and is attached at its other end to a linear motor 19 within linear motor drive 18.

[0155] With reference to Figures 5, 6, and 7, another variation of the pump is illustrated. In these figures, pump 100 is substantially similar to pump 10 in both structure and function, with the difference being found in the configuration of the expandable housing. In comparison to Figures 3 and 4, it is noted that pump 10 utilizes an expandable housing 25 having a cannula or extension portion 28 extending therefrom. Turning to Figure 5, it is noted that pump 100 utilizes an expandable housing 60 that does not have a cannula or extension portion 28. Except for this difference in the structure of the expandable housing, pumps 10 and 100 are substantially the same.

[0156] More specifically, FIG. 5 illustrates a cross-sectional view of the pulsatile pump portion (expandable housing and flexible diaphragm) of pump 100. FIG. 5 shows expandable housing 60 in its collapsed configuration. Expandable housing 60 may be advanced from within outer sheath 11 (shown in FIG. 4). Expandable housing 60 includes an inlet (scaffold portion) 63 proximate end 62, which in turn supports bearing 13 in a fixed attachment. Expandable housing 60 further includes an outlet (scaffold portion) 64 and a chamber 61 within expandable housing 60. Chamber 61 may be formed by overmolding a portion of the scaffold of expandable housing 60 with a polymer layer or by bonding a fabric layer to the scaffold, as previously described. Pump 100 further includes inner sheath 16, which extends through outlet 64 and chamber 61 to an inner end of bearing 13. A tine support 15 is received within inner sheath 16 and includes a plurality of tines 20. A drive cable 40 extends through the inner sheath 16 and is coupled to the tine support 15. A flexible diaphragm 30 is also coupled to the tine support 15.

[0157] 5, the pump 100 has begun to expand the expandable housing 60 while the tine supports 15 remain captured within the inner sheath 16 in a compressed configuration. Thus, the next step in configuring the pump 100 for operation requires removing the inner sheath 16 and allowing the tines 20 to expand and assume their operational expanded configuration.

[0158] FIG. 6 illustrates a cross-sectional view of the pulsatile pump portion of pump 100. As mentioned above, FIG. 6 shows pump 100 at an intermediate point between the compact configuration of FIG. 5 and the operational configuration of FIG. 7. Pump 100 includes an expandable housing 60. Expandable housing 60 includes an inlet 63 proximate end 62, which in turn supports bearing 13 in a fixed mount. Expandable housing 60 further includes an outlet 64 and a chamber 61. Pump 100 further includes inner sheath 16 that has been retracted to a point within outlet 64, thereby releasing tines 20 and diaphragm 30 from capture of inner sheath 16. Expandable housing 60 further includes chamber 61 and end 62. A tine support 15 is received within inner sheath 16 and includes a plurality of tines 20. A drive cable 40 extends through inner sheath 16 and outer sheath 11 and is coupled to tine support 15. A flexible diaphragm 30 is also coupled to the tine support 15 .

[0159] 6, the pump 100 has begun expanding the expandable housing 60 and releasing the tine support 15 from the inner sheath 16. Thus, the next step in configuring the pump 100 for operation requires allowing the tines 20 and diaphragm 30 of the tine support 15 to expand and assume their operational configuration.

[0160] FIG. 7 depicts a cross-sectional view of the pulsatile pump portion of pump 100. As mentioned above, FIG. 6 depicts pump 100 in its operational configuration. Expandable housing 60 includes an inlet 63 proximate end 62, which in turn supports bearing 13 in a fixed mount. Expandable housing 60 further includes a mesh portion 64 and a chamber 61. Pump 100 further includes inner sheath 16 that has been retracted to a point within outlet 64, thereby releasing tines 20 and diaphragm 30 from capture of inner sheath 16. Expandable housing 60 further includes chamber 61 and end 62. Tine support 15 extends partially into bearing 13. Tine support 15 includes a plurality of tines 20 that are expanded to the position shown. Drive cable 40 extends through inner sheath 16 and outer sheath 11 and is coupled to tine support 15. Flexible diaphragm 30 is also coupled to tine support 15 and expands to its fully extended configuration overlapping the outer ends of tines 20 .

[0161] 7, the pump 100 has completed expansion of the expandable housing 60 and released the tine supports 15 from the inner sheath 16, allowing the tines 20 and diaphragm 30 to assume their fully extended positions. Thus, the pump 100 is fully configured for operation.

[0162] In some variations, a pump for assisting blood circulation includes an expandable housing as illustrated in FIGS. 10A-10C. Referring to FIG. 10A, the expandable housing 200 has a cannula 202 extending therefrom. The cannula 202 may have a smaller diameter than the expandable housing 200, which may be useful when the cannula is to cross the aortic valve. The expandable housing 200 may include a scaffold 204, which in some variations may be an expandable stent. The scaffold 204 may include a tapered proximal end 208 and a tapered distal end 210, although this is not required. The distal end 210 may function as an inlet for blood into the expandable housing 200, and the proximal end 208 may function as an outlet for blood exiting the expandable housing 200. To block blood from flowing through the stent openings and to provide a smooth surface over which the flexible diaphragm may reciprocate, the expandable housing 200 may include a layer 206 that is bonded to and / or covers the scaffolding (e.g., stent) 204. FIG. 10B depicts a polymer layer 206 that may be overmolded onto or otherwise attached to the scaffolding 204. The polymer layer 206 may be overmolded onto the scaffolding 204 such that the scaffolding 204 is embedded within or otherwise completely surrounded by the polymer layer 206. FIG. 10C shows the expandable housing 200 and cannula 202 with the polymer layer 206 bonded to the scaffolding 204.

[0163] The expandable housing of FIG. 10C may include a flexible diaphragm, which in some variations may be supported by multiple tines, as shown in FIG. 11. With reference to FIG. 11, a flexible diaphragm 212 may be disposed within a chamber formed within the body of the expandable housing 200, and the flexible diaphragm 212 may have a collapsed configuration and an expanded configuration (as depicted in FIG. 11). The flexible diaphragm 212 may be coupled to an actuator 214 such that linear movement of the actuator 214 results in corresponding linear movement of the diaphragm 212. A plurality of tines 216, which may help support the flexible diaphragm 214 against blood pressure during a pump stroke, are also shown in their expanded configuration. The expandable housing 200, flexible diaphragm 212, and / or tines 216 may be configured to self-expand such that expansion of the expandable housing 200, flexible diaphragm 212, and tines 216 may be achieved by relative motion between the expandable housing 200 and the flexible outer sheath 218, which may constrain the expandable housing 200, flexible diaphragm 212, and / or tines during advancement (e.g., retraction of the outer sheath 218 and / or advancement of the expandable housing 200 relative to the outer sheath 218) to a desired location within the body.

[0164] Instead of multiple tines, the support member for coupling to the flexible diaphragm may be an expandable frame. With reference to FIG. 34, the flexible diaphragm 1800 may be disposed within a chamber formed by an expandable housing 1802. The flexible diaphragm 1800 may have a collapsed configuration and an expanded configuration (as shown in FIG. 34). The flexible diaphragm 1800 may be coupled to an actuator 1804 such that linear movement of the actuator 1804 results in a corresponding linear movement of the flexible diaphragm 1800. The expandable frame 1806, which may help support the flexible diaphragm 1800 against blood pressure during a pump stroke, is also shown in its expanded configuration. The expandable housing 1802, the flexible diaphragm 1800, and / or the expandable frame 1806 may be configured to self-expand.

[0165] In general, a flexible diaphragm contained within the expandable housing creates pressure to move and pump blood from an inlet of the housing, through a chamber within the body of the expandable housing, to an outlet of the housing. As shown in FIG. 12A, flexible diaphragm 300 in its extended configuration includes a diaphragm body 302 and a rim 304 centered around the periphery of body 302. Body 302 and rim 304 of flexible diaphragm 300 are integrally formed. However, in other variations, they may be formed separately and coupled to one another.

[0166] In some variations, the diaphragm body 302 and the rim 304 may have different thicknesses. For example, in some variations, the thickness of the rim 304 may exceed the thickness of the diaphragm body 302, as shown in the cross-sectional view provided in FIG. 12B. The smaller thickness of the diaphragm body 302 may allow the flexible diaphragm to be in its collapsed configuration during the fill stroke or a portion thereof and in an extended configuration during the pump stroke of the pumping cycle. The larger rim thickness may provide additional rigidity to the diaphragm body 302 around the periphery of the diaphragm 300 and may help create a seal between the rim 304 and the inner surface of the expandable housing during the pump stroke.

[0167] Some variations of the pump may include a tine support comprising a base and a plurality of tines coupled to the actuator that support the flexible diaphragm in an extended configuration during a pump stroke. For example, as shown in FIGS. 13A-13C, a tine support 401 includes a base 404 and a plurality of tines 400. The plurality of tines 400 may comprise six (6) flexible metal strips 402 having an expanded configuration (as shown in FIG. 13A) and a compressed configuration (see FIG. 5). The metal strips 402 may have a compressed configuration during advancement of the expandable housing within the vessel to the target location and may expand radially outwardly to an expanded configuration at the target location. Although shown as having a rectangular cross-sectional shape, the plurality of tines 400 may have any suitable shape or geometry, e.g., circular, square, triangular, oval, etc. The metal strips 402 may extend from a common hub or base 404 at one end and may have a free end 406 at the other end. As shown in the cross-sectional view of FIG. 13B, the base 404 may include a bore 408 configured to couple a plurality of tines to the actuator. Although shown as including six (6) metal strips 402, more or fewer strips may be utilized. The metal strips 402 may be equally spaced from one another, as shown in FIG. 13C. However, in some variations, the metal strips 402 may be unequally spaced from one another. Also shown in FIGS. 13A-13C is a sleeve 412, which is a short cylinder that is attached to the free ends 406 of the metal strips 402. The free ends 406 may be attached to the sleeve 412 using any suitable means, such as, for example, by welding, soldering, or gluing. The sleeve 412 provides additional supportive area for the flexible diaphragm to bear against during the pump stroke and may help prevent movement of the flexible diaphragm between the tines during the pump stroke.

[0168] In some variations, the plurality of tines 500 may comprise a plurality of flexible first wires 502, as illustrated in FIGS. 14A-14C. Although each tine of the plurality of tines in the figures is shown to include two first wires 502, they may include one wire or more than two wires. A plurality of holes (not shown) corresponding to the number of first wires 502 may be formed (e.g., drilled) in the base 504 of the tine support 501 such that one end of the wire may be inserted into the hole. At the other end (free end 506) of the wire, a sleeve 508 is attached in the same manner as described above. More specifically, in FIGS. 14A-14C, a pair of first wires 502 are attached at their free ends 506 to the same sleeve to form one tine of the plurality of tines. Thus, when twelve (12) first wires are paired, six (6) tines are formed. The sleeves 508 may each include a central hole 510 through which a second wire 512 may be threaded. After being threaded through all of the sleeves 508, the ends of the second wire 512 may be joined by soldering, welding, glueing, and / or the like. The second wire may provide additional flexible diaphragm support during the pump stroke to that provided by the sleeve, such that movement of the flexible diaphragm between the tines during the pump stroke may be prevented or minimized. As shown in the cross-sectional view of FIG. 14B, the base 504 may include a bore 514 configured for coupling to an actuator. The first wires 502 may be equally spaced from each other, as shown in FIG. 14C. However, the first wires 502 may also be configured to be unequally spaced from each other.

[0169] Other pump variations may not include multiple tines supporting the flexible diaphragm. For example, as shown in FIG. 15, a flexible conical diaphragm 600 is disposed within an expandable housing 602. The flexible diaphragm 600 may have a compressed configuration and an extended configuration, and may have a conical shape when in the extended configuration. As shown in FIG. 16A (end view) and 16B (side view), the flexible diaphragm 600 may include a diaphragm body 604 and a rim 606 centered around the periphery of the body 602. As depicted in FIG. 16A-16B, the body 604 and rim 606 of the flexible diaphragm 600 may be integrally formed and may be formed from the same material. However, in other variations, they may be separate components and / or may include different materials.

[0170] In some variations, the body 604 and the ribs 606 may have the same thickness, while in other variations, the thickness of the body 604 and the rim 606 may differ. For example, in some cases, it may be advantageous to utilize a diaphragm with a rim 606 that has a thickness greater than the body 604. Turning to FIG. 17, shown therein is an enlarged cross-sectional view of the diaphragm 600 in an extended configuration, coupled to an actuator 612 and positioned within a chamber of the body of the expandable housing 614. The rim 606 contacts the inner surface 612 of the expandable housing 614 such that a seal 610 can be formed between the expandable housing 614 and the diaphragm 600. Also, as can be seen in FIG. 17, the rim 606 of the diaphragm 600 has a thickness greater than the diaphragm body 604. The greater thickness of the perimeter 606 may help create a seal 610 between the perimeter 606 and the expandable housing's inner surface 612 during the pump stroke, while still allowing the diaphragm body 606 to have the necessary flexibility for collapse during the filling stroke. In this variation, the conical shape of the diaphragm helps seal the diaphragm against the inner surface 612 and also prevents eversion of the diaphragm as pressure from the blood flow (in the direction of the arrows) pushes against it.

[0171] In some variations, the flexible diaphragm may include one or more (e.g., multiple, two, three, four, five, six, or more) ribs. With reference to the cross-sectional view provided in FIG. 16C, multiple ribs 608 may extend from a central portion 601 to a peripheral edge 606 of the diaphragm body 604. The multiple ribs 608 may be employed to maintain a conical shape of the diaphragm body 604 during a pump stroke. The multiple ribs 608 may have a rib angle between a longitudinal axis of each rib and an axis perpendicular to the actuator of about 60 degrees. Although the multiple ribs 608 are shown as being equally spaced from each other, in some instances they may be unequally spaced from each other.

[0172] Instead of a flexible diaphragm, the pump may include a valve cone as a linearly reciprocating valve member. In one variation, as illustrated in FIGS. 25A-25C, the valve cone 1200 may include an expandable frame 1202, a mesh cone 1204, and a flow control cone 1206. The flow control cone 1206 includes a plurality of arc-shaped flaps 1212. Other flap shapes may also be used. Additionally, although the expandable frame 1202, mesh cone 1204, and flow control cone 1206 are shown as being conically shaped, they may be formed to have different shapes. The expandable frame 1202 may be a stent-like structure having an expanded configuration at one end and a collapsed configuration. In the expanded cone shape shown in the figures, the expandable frame 1202 contains a mesh cone 1204 and a flow control cone 1206 within a cone 1208 of the frame 1202. The flow control valve 1200 may be generally configured such that the mesh cone 1204 seats between the flow control cone 1206 and the expandable frame 1202. In this configuration, as illustrated in FIG. 25B, the multiple flaps 1212 open in the direction of arrow A when blood is drawn into the expandable housing through the mesh cone during the fill stroke and close when blood is moved out of the expandable housing in the direction of arrow B during the pump stroke. The mesh cone 1204 may be disposed between the flow control cone 1206 and the expandable frame 1202 and provide support to the flaps 1212 of the flow control cone 1206 so that the flaps 1212 are not pushed or bent through the openings 1201 in the expandable frame 1202 when pressure on the flaps 1212 is applied during the pump stroke. Thus, the mesh cone 1204 may help maintain the flaps 1212 in a closed configuration during the pump stroke when blood is moved out of the housing via the housing outlet. However, during the fill stroke, the mesh cone 1204 allows blood to flow from the housing inlet through the holes in the mesh and then through the flaps 1212, transitioning them to their open configuration so that blood can move to the outlet side of the valve cone.The mesh cone 1204 and the flow control cone 1206 may be sewn to the expandable frame 1202 at multiple attachment points 1210, as shown in Figure 25C. Other mechanisms for attaching the material layers to the expandable frame may also be employed.

[0173] The expandable frame 1202 is shown separate from the remainder of the valve cone depicted in FIGS. 26A-26C. FIG. 26A provides a perspective view of the expandable frame 1202, FIG. 26B provides a side view of the frame 1202, and FIG. 26C provides a top view of the frame 1202. As shown in the figures, the expandable frame 1202 may include a first end 1214 and a second end 1216. The first end 1214 may be coupled to an actuator for reciprocating the valve cone back and forth within the housing. The second end 1216 is generally expandable and forms a shaped end, for example, a cone shape 1208. The expandable frame 1202 may comprise a plurality of cells 1218, which may be diamond shaped. However, the cell shapes are not so limited and they may have any suitable shape. In addition, the cells may have any suitable size. In one variation, the cells may be sized smaller than the flaps in the flow control cone so that the flaps are not pushed through the cells during a pump stroke.

[0174] In Figures 27A and 27B, the mesh cone 1204 is shown separate from the remainder of the valve cone depicted in Figures 25A-25C. With reference to Figure 27A, the material of the mesh cone 1204 may be initially provided as a circular layer 1220 with a center cutout 1222 and slits 1224 extending from the cutout 1222 to the periphery 1226 of the circle. The slits 1224 provide a free edge so that the circular layer 1220 may be subsequently rolled to form the mesh cone 1204. The conical shape of the mesh cone 1204 may be maintained by sewing, heat sealing, gluing, etc. the mesh material. The height (H) of the mesh cone 1204 may be from about 1.0 cm to about 2.0 cm, including all values ​​and subranges therein. For example, the height of the mesh cone may be about 1.0 cm, about 1.1 cm, about 1.2 cm, about 1.3 cm, about 1.4 cm, about 1.5 cm, about 1.6 cm, about 1.7 cm, about 1.8 cm, about 1.9 cm, or about 2.0 cm.

[0175] 28A-28C depict the flow control cone 1206 separate from the remainder of the valve cone depicted in FIGS. 25A-25C. With reference to FIG. 28A, the material for the flow control cone 1206 may first be provided as a circular layer 1228 with a center cutout 1230 and slits 1232 extending from the cutout 1230 to the periphery 1234 of the circle. The slits 1232 provide a free edge so that the circular layer 1228 can later be rolled to form the flow control cone 1206. The flaps 1212 may then be formed by laser cutting or stamping a flap shape into the circular layer 1228. The flaps 1212 are shown as arc-shaped in the figures, but may have any suitable size and shape, as described above. Referring to FIG. 28B, a perimeter 1236 may be created around the perimeter of the circular layer 1228 by rolling an edge of the layer onto itself to create a thickness at the perimeter 1234, and then sewing, heat sealing, gluing, etc., the rolled edge to maintain the thickness in that area. After the perimeter 1236 is formed, the free edge of the slit 1232 is rolled to mold the circular layer 1228 into the flow control cone 1206. The perimeter 1236 may help create a seal between the flow control cone 1206 and the inner surface of the housing during the pump stroke. The cone-shaped flow control cone 1206 may be held together by sewing, heat sealing, gluing, etc., a mesh material. The height (H) of the flow control cone 1204 may be from about 1.0 cm to about 2.0 cm, including all values ​​and subranges therein. For example, the height of the flow control cone can be about 1.0 cm, about 1.1 cm, about 1.2 cm, about 1.3 cm, about 1.4 cm, about 1.5 cm, about 1.6 cm, about 1.7 cm, about 1.8 cm, about 1.9 cm, or about 2.0 cm.

[0176] In some variations, the flow control cone may include one or more slits that extend radially outward from a central portion of the flow control cone but terminate before an outer edge of the flow control cone that may form multiple flaps. For example, the flow control cone may be cut to create one or more slits and thus multiple flaps. The multiple flaps may be of any suitable size and shape that allows blood to flow into the housing during the filling stroke. In general, the flow control cone may be configured such that a greater number of flaps may be included when they are smaller in size and a fewer number of flaps may be included when they are larger in size. For example, as shown in Figures 29A and 29B, three triangular shaped flaps may be employed when the flaps are larger in size. Figure 29A shows the side of the flow control cone that would face the outlet of the pump housing, and Figure 29B shows the side of the flow control cone that would face the inlet of the pump housing. Referring to the figure, the valve cone 1300 includes a flow control cone 1302 that is disposed within and covers an expandable frame 1304. Three slits 1306 in the flow control cone 1302 form three triangular shaped flaps 1308 in the flow control cone 1302. The expandable frame 1304 supports the flow control cone 1302 so that when pressure is applied against the flaps 1308 during a pump stroke, the flaps are not pushed through openings 1310 in the expandable frame 1304. However, during a fill stroke, the expandable frame 1304 allows blood to flow from the housing inlet, through the expandable frame openings 1310, and then through the flaps 1308, lifting them off the surface of the expandable frame 1304 so that blood can move to the outlet side of the flaps 1308.

[0177] In further variations, the flow control cone may include a membrane and a number of struts arranged in an umbrella structure and may have an open configuration and a collapsed configuration. For example, the membrane may be coupled to and supported by the number of struts. Any suitable number of struts may be included. For example, the number of struts may range from 3 to 10. For example, 3 struts, 4 struts, 5 struts, 6 struts, 7 struts, 8 struts, 9 struts, or 10 struts may be employed. In general, the flow control cone including the membrane and a number of struts may have a collapsed configuration during a fill stroke (FIGS. 30A and 30B) and an open configuration during a pump stroke (FIGS. 30C and 30D). With specific reference to FIGS. 30A-30D, the valve cone 1400 includes an expandable frame 1402 and a flow control cone 1404 disposed within the expandable frame 1402. As shown in more detail in FIGS. 30B and 30C, the flow control cone 1404 may comprise an umbrella structure including a membrane 1406 having a perimeter 1412 and a number of struts 1408. The membrane 1406 is coupled at one end to the expandable frame 1402 via a weld ring 1410. The perimeter 1412 is a free edge that is not attached to the expandable frame 1402. During a fill stroke, the collapse of the membrane 1406 allows blood to flow from the housing inlet through the expandable frame opening 1414 to fill the pump of the housing. During a pump stroke, the expandable frame 1402 supports the membrane 1406 such that when pressure is applied against the membrane 1406, the membrane 1406 transitions to its open configuration and covers the expandable frame opening 1414, thus preventing blood from being displaced to the outlet side of the housing and flowing back towards the inlet side. However, as mentioned above, in some variations, the expandable frame 1402 may not be required and the membrane 1406, including multiple struts 1408, reciprocates linearly without the expandable frame 1402 to generate pump and fill strokes.

[0178] An umbrella structure that may reciprocate linearly without an associated expandable frame is shown in FIGS. 35A-35C and 36A-36C. In the figures, the umbrella structure may include a membrane, a number of struts, and an anchor. The membrane may completely or partially cover the struts. With reference to FIG. 35A, an umbrella structure 1900 is shown with a membrane 1902 that completely covers a number of struts 1904, and an anchor 1906 having a proximal end 1908 and a distal end 1910. As shown in the side view of FIG. 35B, the struts 1904 may diverge radially outward to form a conical shape and create a strut angle (SA) of 40 degrees relative to the longitudinal axis 1912 of the umbrella structure 1900. In a variation shown in FIG. 35C, the strut angle (SA) is also 40 degrees, but the struts 1914 include an additional bend 1916. The bend angle (BA) of the struts formed therefrom may be 30 degrees relative to the longitudinal axis 1918 of the umbrella structure 1920. In yet a further variation, as shown in FIGS. 36A-36C , the umbrella structure 2000 also includes a membrane 2002, a plurality of struts 2004 having a proximal end 2005 and a distal end 2006, and an anchor 2008 having a proximal end 2010 and a distal end 2012. In this variation, the struts 2004 may have a ski-like profile, with the distal ends 2006 of the struts 2004 including a bend and the middle section 2007 being flattened and of a greater width than the proximal ends 2005 or the distal ends of the struts 2004. The membrane 2002 may partially cover the plurality of struts 2004. The distal ends 2006 of some of the plurality of struts may include rounded tips 2014. The rounded tip 2014 may include a radiopaque marker. Referring to FIG. 36C, a side view of the umbrella structure 2000 is provided showing a strut angle (SA) of 40 degrees relative to the longitudinal axis 2016 of the umbrella structure 2000. Additionally, the struts 2004 each include a bend 2018 at the strut distal end 2006. The strut bend angle (BA) formed therefrom may be 15 degrees relative to the longitudinal axis 2016 of the umbrella structure 2000.

[0179] The umbrella structure may include components that facilitate collapsing of the struts during the filling stroke of a pumping cycle. In some cases, the components may be pivot mechanisms, e.g., hinges, or flexible connectors that increase the flexibility of the struts at that point. The pivot mechanisms or flexible connectors may attach the struts to the anchors at the proximal or distal ends of the anchors. For example, as shown in FIG. 48, a valve member 4000 may include an umbrella structure 4001 that includes a plurality of struts 4002. The struts 4002 may be attached to the proximal end 4003 of the anchor 4004 by a pivot mechanism 4006.

[0180] Instead of extending radially from the anchor, the struts may invert (e.g., fold back) about the anchor, forming, for example, a cone shape. For example, as shown in FIG. 39A , an umbrella structure 2300 includes a plurality of struts 2302 that are inverted about an anchor 2304. The anchor 2304 may include a proximal end 2306 and a distal end 2308. When the plurality of struts 2302 are inverted, an actuator (not shown) may generally be attached to the proximal end 2306 of the anchor 2304. In contrast, when the plurality of struts 2302 extend radially from the anchor 2304 and are not inverted, an actuator (not shown) may generally be attached to the distal end 2308 of the anchor 2304. A membrane 2310 may also cover the plurality of struts 2302, as shown in FIG. 39B . Although shown as completely covering the struts in the variation of FIG. 39B, in some variations the membrane may only partially cover the struts.

[0181] The distal tips of the struts may be configured to be atraumatic, as mentioned above. In one variation, the atraumatic distal tips may be shaped to help prevent the struts from damaging the inner surface of the housing during a pump stroke. For example, the atraumatic distal tips may have a rounded or oval shape as shown in FIG. 40. Referring to FIG. 40, a plurality of struts 2400 are shown including distal ends 2402 having an oval (e.g., paddle-like) shape. Additionally or alternatively, one or more slits or cutouts 2404 may be provided along the length of the struts to increase strut flexibility, which may help prevent the struts from damaging the inner surface of the housing during a pump stroke.

[0182] In some variations, the distal tip of one or more struts may include an opening that allows blood flow therethrough. The opening may have a variety of sizes and shapes, which may depend on the size and shape of the distal end. The opening may be shaped to be circular, oval, square, rectangular, triangular, and the like. In one variation, the opening at the distal tip is rectangular in shape. In another variation, the opening at the distal tip is circular in shape. With reference to FIG. 41, a valve member 2500 includes a plurality of struts 2502 having a circular distal tip 2504 and a membrane 2508 that extends beyond the distal tip 2504, for example, about 1.0 mm to about 2.0 mm beyond the distal tip, including all values ​​and subranges therein. For example, the membrane may extend about 1.0 mm, about 1.1 mm, about 1.2 mm, about 1.3 mm, about 1.4 mm, about 1.5 mm, about 1.6 mm, about 1.7 mm, about 1.8 mm, about 1.9 mm, or about 2.0 mm beyond the distal tip. Each circular distal tip 2504 includes a circular opening 2506. Although all of the distal ends of the struts are depicted in FIG. 41B with openings, in some variations only a portion of the distal ends may include openings (e.g., in one-fifth of the struts, in one-quarter of the struts, in one-third of the struts, in one-half of the struts). Radiopaque markers 2510 may also be provided at any suitable location along the length of the struts, for example, at the distal ends of one or more struts (e.g., one-third of the struts, half of the struts, all of the struts). In lieu of radiopaque markers, a portion of the strut may be coated with a radiopaque material.

[0183] In other variations, the umbrella structure may include a bend and an opening in one or more of the struts. In some variations, the inclusion of both of these features may further help minimize the risk of the struts puncturing the housing during the pump stroke. With reference to FIGS. 42A-42C, an umbrella structure 2600 may include a membrane 2602, a number of struts 2604, and an anchor 2606. An actuator 2608 (e.g., a drive tube) linearly reciprocates the umbrella 2600, causing it to expand during the pump stroke and collapse during the fill stroke. The struts 2604 may include a bend 2614. The portion of the strut 2604 distal to the bend 2614 may form a distal tip 2610 of the strut 2604. The distal tip 2610 may include an opening 2612 that allows for the flow of blood therethrough. While the shape of the opening 2612 corresponds to the shape of the distal tip 2610 in the variation shown in FIG. 42A, it should be understood that this need not be the case and other shapes may be used and the shape of the opening need not correspond to the shape of the distal tip 2610. For example, the shape of the distal tip may be oval, while the opening may be square shaped. The umbrella structure 2600 may include ten struts 2604, although in other variations, as noted herein, a lesser or greater number of struts may be employed. As shown in FIG. 42B, the struts 2604 may be equally spaced about the circumference of the membrane 2602. Referring to FIG. 42C, an assembly view of a variation of a valve member 2618 including an umbrella structure 2600 is provided. In the variation depicted therein, the valve member 2618 includes an umbrella structure 2600 comprising a membrane, a plurality of struts 2604, an anchor 2606, and an actuator 2608 (e.g., a drive tube). The membrane may be formed from multiple layers, for example, by sealing an outer layer of material 2620 to an inner layer of material 2622 with the umbrella structure 2600 therebetween. The sealing of the outer and inner layers may be accomplished in a variety of ways, for example, by the use of heat, pressure, and / or adhesives. The ring 2616 may also be attached to the inner layer 2622 by heat or pressure sealing or by employing an adhesive.The ring 2616 may further include a number of openings through which the posts 2604 may extend. The ring 2616 may thicken the membrane edge and aid in contact between the membrane 2602 and the housing (not shown) during the pump stroke.

[0184] The inner layer, outer layer, and ring may be made of the same material or different materials. In some variations, one or more of the inner layer, outer layer, and ring may include an elastomeric polymer. Non-limiting examples of elastomeric polymers include silicone, polyester, polyurethane, fluoropolymer, or combinations thereof. Fluoropolymers that may be employed include polytetrafluoroethylene (PTFE) or expanded polytetrafluoroethylene (ePTFE). In one variation, the inner layer, outer layer, and ring are made of PTFE. In another variation, the inner layer, outer layer, and ring are made of ePTFE.

[0185] Other variations of the pump may include a valve member with an element that limits its expansion. For example, the valve member may include an expandable frame bonded to a polymer layer, where a number of control lines or tethers attach the valve member to a pump actuator. The tethers may have a relaxed state and a tensioned state, and may have a length that limits the expansion of the valve member so that they contact and create a seal with the inner surface of the pump housing during the pump stroke of a pumping cycle without creating excessive friction. The length of the tether may also be adjusted so that a small gap is created between the valve member and the inner surface of the pump housing during the pump stroke. During the filling stroke, the valve member may collapse to a collapsed configuration, which in turn may move the tethers to the relaxed state. During the pump stroke, the valve member may expand to an expanded configuration, which may transition the tethers from the relaxed state to the tensioned state.

[0186] For example, referring to FIG. 31 , an exemplary valve member disposed within an expandable housing 1500 is shown. The valve member includes a frame 1502, which may be a hollow hemispherical structure made from Nitinol and coated with a thin polymer. The frame 1502 may have an expanded configuration and a collapsed configuration. When expanded, the element frame may have a diameter of about 20 mm. A plurality of control lines 1504 attach an open end 1508 of the frame 1502 to a pump actuator 1506. Additionally, a check valve 1510 may be included within the pump. During the filling stroke, the hydraulic pressure of the blood may partially collapse the frame 1502, allowing blood to flow around it. At the start of the filling stroke, the closing of the check valve 1510 may ensure rapid collapse of the frame 1502. When the stroke is reversed to the pump stroke of the pump cycle, the check valve 1510 may open and the frame 1502 may expand to its expanded configuration. The control lines 1504 can adjust the sealing pressure of the element against the housing 1500 during the pump stroke to prevent excessive pressure from being applied that can create excessive friction. The check valves can also be equipped with alternative valve members described herein to aid in their collapse and expansion.

[0187] In some variations, the pump may include an expandable housing with multiple openings or perforations in its body, as mentioned above. The openings may be through-wall openings in the body (e.g., through both the scaffold and the layer) so that blood from the chamber of the expandable housing's body may flow directly from within the chamber to outside the chamber without passing through an inlet or back through an outlet. When openings are included, a skirt may be coupled to or extend from the outer surface of the expandable housing in a manner that surrounds, overlies, or otherwise covers the multiple openings to direct blood flowing through the openings. For example, the skirt may be configured to generate retrograde blood flow that is directed toward the patient's heart during the pump stroke of the pumping cycle. Retrograde blood flow may help provide proper perfusion of arteries branching from the aortic arch, such as the carotid and subclavian arteries.

[0188] 19, the pump 800 may include an expandable housing 802 including a plurality of openings 804 and a cylindrical skirt 806 coupled to the expandable housing 802 in a spaced-apart manner therefrom. The skirt 806 may be coupled to an outer surface of the housing 802 and circumferentially (or partially circumferentially) surround it and overlie at least a portion of the plurality of openings 804. The skirt 806 may comprise a first diameter at its proximal end and a second, larger diameter at its distal end such that the skirt 806 may be coupled to the housing 802 at its proximal end but then widen or spaced from the plurality of openings 804 formed in the housing 802 to allow retrograde flow of blood therethrough. The skirt 806 and the expandable housing 802 may be integrally formed as a single piece or they may be separate components coupled to one another by friction fit, adhesives, welding, soldering, and / or the like. At the proximal end 801 of the expandable housing 802, an outlet 808 may be provided for antegrade blood flow to the body. A cannula 810 may be coupled to the expandable housing 802 and may extend from a distal end 820 of the housing, through the aorta 816 and the aortic valve 822, and into the left ventricle 814. At the distal end 824 of the cannula 810, an inlet 812 may be provided for blood entry from the left ventricle 814. The cannula may have a variety of lengths. Various lengths may be used to accommodate factors such as different patient anatomies, patient sizes or ages, desired locations of pump placement, and / or points of access to the circulatory system. While any suitable length may be utilized, the cannula may have a short, medium, or long length as described above. In FIG. 19, the cannula 810 has a medium length ranging from about 25 cm to about 30 cm.

[0189] 20, an enlarged view of the pump 800 of FIG. 19 is shown. Cutouts are provided within the expandable housing 802 to further illustrate the structure and configuration of the skirt 806 in relation to the plurality of openings 804. In FIG. 20, the housing 802 includes a plurality of openings 804 at its distal end 820. The skirt 806 is concentrically disposed about the expandable housing 802 and overlies the plurality of openings 804. In addition, the skirt 806 is configured such that a space 805 is provided between the plurality of openings 804 and the skirt 806. In use, as the flexible diaphragm 803 is moved toward the outlet 808, blood within the expandable housing 802 is pushed in the direction of arrow 826 through the outlet 808 of the expandable housing 802 toward the patient's foot. During the movement of the flexible diaphragm 803, a first portion of blood is pushed through the plurality of openings 804 as the flexible diaphragm passes by them. A first portion of the blood is pushed into the space 805 and then directed by the skirt 806 back toward the heart in the direction of arrow 828. As the flexible diaphragm 803 continues to move toward the outlet 808, the portion of the blood that remains within the expandable housing 802 (the second portion) is pushed through the outlet 808 toward the feet and to the rest of the body. The combination of the number of openings and the diameter of each opening can provide an amount of open surface area on the expandable housing for retrograde blood flow. In addition, the skirt can be configured to adjust the amount of open surface area for retrograde flow by adjusting the number of openings that are patent (open) and closed. In general, a larger amount of open surface area can provide more retrograde blood flow toward the patient's head, and a smaller amount of open surface area can provide more antegrade blood flow to the body.

[0190] Some variations of pumps may be used to assist renal perfusion. In these variations, the pump may include any combination of the structures described herein. For example, the pump may include a housing and a linearly reciprocating member with a valve, e.g., a flexible diaphragm, a valve cone, an umbrella structure, or an inverted umbrella structure, disposed within the housing. The housing may be expandable and may include an inner surface, an expanded configuration, and a collapsed configuration. A sheath, which may be disposed about the housing, may maintain the housing in the collapsed configuration during advancement to the target location. In response to reaching the target location, the sheath may be retracted to allow expansion of the housing to the expanded configuration.

[0191] In some variations, the renal perfusion pump is configured as shown in FIG. 33. With reference to the figure, the pump 1700 is shown positioned in the descending aorta 1702 above the renal artery 1704. The pump 1700 may include a valve member 1706 in a housing 1708 that reciprocates linearly to increase perfusion of the kidney 1710. In this variation, the housing 1708 may lack a cannula. The housing 1708 may include a plurality of cells 1707 having a diamond shape upon expansion of the housing 1708. However, it should be understood that the struts may form wider or narrower diamond shapes or may be configured to form other cell shapes. For example, instead of a diamond shape, the cells 2700 may be oval in shape, as shown in FIG. 43. Other cell shapes may include circles, triangles, squares, rectangles, etc. In variations that include a cannula 2802, the expandable housing 2800 may also include diamond shaped cells 2804, as illustrated in FIG 44. In further variations, the struts 2902 of the expandable housing 2900 may be straight and extend parallel to one another, as shown in FIG 45.

[0192] As described above, when in its expanded configuration, the housing may have a diameter ranging from about 12 mm to about 30 mm, including all subranges therein. For example, the housing may have a diameter of about 12 mm, about 13 mm, about 14 mm, about 15 mm, about 16 mm, about 17 mm, about 18 mm, about 19 mm, about 20 mm, about 21 mm, about 22 mm, about 23 mm, about 24 mm, about 25 mm, about 26 mm, about 27 mm, about 28 mm, about 29 mm, or about 30 mm in its expanded configuration. Additionally, the housing chamber of the renal perfusion pump may have a length ranging from about 2.5 cm to about 10 cm in its expanded configuration, including all values ​​and subranges therein. For example, the housing chamber may have a length in its expanded configuration of about 2.5 cm, about 3.0 cm, about 3.5 cm, about 4.0 cm, about 4.5 cm, about 5.0 cm, about 5.5 cm, about 6.0 cm, about 6.5 cm, about 7.5 cm, about 8.0 cm, about 8.5 cm, about 9.0 cm, about 9.5 cm, or about 10 cm.

[0193] Some variations of the expandable housing may also include one or more enlarged ends having a diameter larger than that of the housing in its expanded state. In some cases, the diameter of the enlarged end may be about 1.5 times to about 2 times larger than the diameter of the expanded housing. The one or more ends may be self-expandable. The expansion at the one or more ends may aid in anchoring the housing within a vessel, for example, the descending aorta. The one or more ends may be expanded to anchor within a blood vessel having a diameter ranging from about 15 mm to about 25 mm, including all values ​​and subranges therein. For example, the one or more ends may be expanded to anchor within a blood vessel having a diameter of about 15 mm, about 16 mm, about 17 mm, about 18 mm, about 19 mm, about 20 mm, about 21 mm, about 22 mm, about 23 mm, about 24 mm, or about 25 mm. In some variations, the housing may include one enlarged end. In other variations, the housing may include two enlarged ends. Depending on the expansion, the ends may be configured to have the same or different shapes. For example, referring to Figures 46A, 46B, 47A, and 47B, the housing 2900, 3000 includes two expansion ends, a first expansion end 2902, 3002 and a second expansion end 2904, 3004. The first expansion end 2902, 3002 has a rounded shape, while the second expandable end 2904, 3004 has a taper 2906, 3006. The shape of the expansion ends may be different and may depend, for example, on the orientation of the struts and / or the shape of the cells formed by the struts.

[0194] The housing may further comprise a covering, coating, or layer configured to block the flow of blood, as previously described herein. The covering, coating, or layer may be provided on the entire housing or on a section or portion of the housing. In some variations, the covering, coating, or layer may be provided on a length of the housing ranging from about 1.0 cm to about 6.0 cm, including all values ​​and subranges therein. For example, the coated length of the housing may be about 1.0 cm, about 1.5 cm, about 2.0 cm, about 2.5 cm, about 3.0 cm, about 3.5 cm, about 4.0 cm, about 4.5 cm, about 5.0 cm, about 5.5 cm, or about 6.0 cm. Referring to Figures 46B, 47A, and 47B, the coating 2908, 3008 may be provided on a portion of the housing 2900, 3000 between the first expandable end 2902, 3002 and the second expandable end 2904, 3004. As shown in FIG. 47B, the valve member 3010 may reciprocate within the coated length of the housing.

[0195] When the valve member is a flexible diaphragm, the flexible diaphragm may have an extended configuration and a collapsed configuration and may include a diaphragm body and a periphery, as mentioned above. Similarly, when the valve member is a valve cone, the valve cone may have an expanded configuration and a collapsed configuration and may include a layer with multiple flaps that allows blood flow into the housing during the filling stroke but prevents blood flow through the valve cone during the pump stroke. Bearings within the expandable housing may also be provided to prevent movement of the flexible diaphragm or valve cone within the housing. When the valve member is an umbrella structure, the umbrella may include a membrane having a body and a periphery, a frame with multiple struts, and an anchor, as described above, and may have an expanded configuration and a collapsed configuration.

[0196] The distal tip of the strut may be configured to be atraumatic, as mentioned above. In one variation, the atraumatic distal tip may be shaped to help prevent the strut from damaging the inner surface of the housing during the pump stroke. For example, the atraumatic distal tip may have a rounded or oval shape. Additionally or alternatively, one or more slits or cutouts may be provided along the length of the strut to increase strut flexibility, which may help prevent the strut from damaging the inner surface of the housing during the pump stroke. In some variations, the distal tip may include an opening that allows blood to flow therethrough. The opening may have various sizes and shapes, which may depend on the size and shape of the distal end. The opening may be shaped to be circular, oval, square, rectangular, triangular, etc. In one variation, the opening at the distal tip is rectangular in shape. In another variation, the opening at the distal tip is circular in shape. Radiopaque markers may also be provided at any suitable location along the length of one or more struts, for example, at the distal end of one or more struts (e.g., one-third of the struts, half of the struts, all of the struts). In some variations, the umbrella structure may include a bend and an opening in one or more of the struts. The inclusion of both of these features may help minimize the risk of the strut puncturing the housing during a pump stroke.

[0197] The renal perfusion pump linearly reciprocates in the same manner as described above. Briefly, the renal perfusion pump may include an actuator coupled to a valve member (e.g., a flexible diaphragm, valve cone, or umbrella structure) via a support element, which may be configured to linearly reciprocate the valve member within the housing to generate the fill stroke and pump stroke of a pumping cycle. The periphery of the valve member may be configured to maintain contact with the inner surface of the housing during the pump stroke. However, the support elements may generally be sized and / or shaped such that they do not contact the inner surface of the housing while they linearly reciprocate within the housing. The pump may be driven by an external linear motor drive and linear motor controller, which may be mounted at the proximal end of a catheter outside the patient. The linear motor drive may be operatively coupled to the pump by a cable or other actuator. Additionally, the pump may be powered by an AC or DC source.

[0198] The pumps described herein may be driven by an external linear motor drive and linear motor controller mounted at the end of a catheter outside the patient. The linear motor drive may be operatively coupled to the pump by a flexible cable or other flexible actuator extending through the catheter. For example, as shown in FIG. 22A, a pump 900 may be coupled to a linear motor drive 902 and a linear motor controller 904 via a catheter 906. The linear motor drive 902 and the linear motor controller 904 may be mounted outside the patient in a console 908. The catheter 906 may be coupled to an expandable housing 910 of the pump 900, as shown in a close-up view in FIG. 22B. Here, the expandable housing 910 includes a plurality of openings 914 and a skirt 912 concentrically disposed about the opening 914. A cannula 916 may extend from the expandable housing 910 such that a distal end 918 of the cannula 916 may be positioned within the left ventricle 920. As shown in a close-up view in FIG. 22C, an inlet 922 may be provided at the distal end 918 of the cannula 916. The inlet 922 may draw blood from the left ventricle 920 into the expandable housing 910 for systemic pumping. The linear motor controller 904 may further be configured to control the pump 900. In some variations, the linear motor controller 904 may be configured to control the pump 900 via sensor feedback, such as, for example, pressure sensor feedback. For example, as described above, one or more pressure sensors (not shown) may be mounted in or on the inlet 922 of the cannula 916 and one or more pressure sensors may be mounted in or on the outlet 924 of the expandable housing 910. In some variations, two pressure sensors may be mounted in or on the inlet 922 and / or outlet 924 for redundancy. For example, referring to FIG. 24A, the pump 1100 may include two pressure sensors 1102 on the distal end of the inner sheath 1103 at the pump outlet 1104, and another two pressure sensors 1106 may be disposed on the nose cap 1105 at the pump inlet 1108.24B and 24C show close-up views of the pressure transducer at the pump outlet 1104 and pump inlet 1108. The controller 904 may be configured to have predetermined high and low blood pressure set points. When measurements from the pressure transducer indicate that the blood pressure has dropped below the low set point, the controller 904 may increase the speed of the linear reciprocating motion, and / or when measurements from the pressure transducer indicate that the blood pressure has increased above the high set point, the controller 904 may decrease the speed of the linear reciprocating motion, thereby reducing the flow and bringing the blood pressure back within the target range.

[0199] Turning to FIGS. 23A-23C, in some variations, the pump may be located outside the body, for example, in a console at the patient's bedside. A coaxial catheter may be coupled to the pump at one end and inserted into the patient at the other end such that blood flows between the patient and the external pump. The coaxial catheter may include an inflow lumen and an outflow lumen. Similar to that described with respect to FIG. 22A, the external pump may be driven by a linear motor drive and a linear motor controller mounted on the end of the coaxial catheter outside the patient. The linear motor drive may be operatively coupled to the pump by any suitable connector or coupling, for example, a quick connect coupler. For example, as shown in FIG. 23A, an external pump 1000 may be coupled to the coaxial catheter 1006 via inlet and outlet tubes 1016. The pump 1000 may also be coupled to a linear motor drive 1002 and a linear motor controller 1004 in a console 1008. The console 1008 may also include a power supply 1010, a battery 1012, and / or a user interface 1014. The coaxial catheter may include an inflow lumen 1018 and an outflow lumen 1020, as shown in a close-up view provided in FIG. 23B. The distal end of the coaxial catheter 1006 is illustrated in a close-up view provided in FIG. 23C, where blood is shown being pulled from the left ventricle 1024 into the inflow lumen 1018 at the pump intake end and pushed out of the outflow lumen 1020 at the pump exhaust end just above the aortic valve 1022. The linear motor controller 1004 may be further configured to control the pump 1000 via pressure transducer feedback, as described in more detail herein. For example, one or more pressure transducers (not shown) may be mounted in or on the inflow lumen 1018 and another pressure transducer may be mounted in or on the outflow lumen 1020. In some variations, two pressure transducers may be mounted in or on the inflow and outflow lumens for redundancy. method

[0200] Methods for pumping blood using a linear reciprocating pump are also described herein. Utilizing a linear pump, as opposed to a rotary pump, can help avoid shear forces that cause red blood cell damage and can pump blood in a pulsatile manner, mimicking the heart's natural pumping cycle. In order for the pump to generate sufficient blood pressure to move blood peripherally, the linearly reciprocating member may be configured such that a seal is created between it and the pump housing during the pump stroke of the pumping cycle. The pump may be placed in various parts of the patient's circulatory system, such as the left ventricle, right ventricle, and aorta. However, in some cases, it may be useful to place the pump external to the patient. A linear reciprocating pump may be placed to assist with heart failure resulting from, for example, myocardial infarction, high blood pressure, trauma, and cardiac malformations.

[0201] As a first step, the method may include accessing the patient's circulatory system. Access may generally be accomplished using the Seldinger technique, whereby a guidewire is placed in the desired artery or vein, and the pump is advanced over the guidewire to the target location. Arterial access may be obtained, for example, from the femoral artery or carotid artery. Arterial access may be useful when the target location for the pump is the left ventricle or aorta. Venous access may be obtained, for example, from the femoral vein or internal jugular vein. Venous access may be useful when the target location for the pump is the right ventricle. The guidewire may be slidingly advanced through a lumen of a pump actuator, such as a drive line, cable, or rod, that linearly reciprocates a valve member, for example, a valve cone or flexible diaphragm, within an expandable housing of the pump.

[0202] The method may also include advancing a pump to a target location within the patient's circulatory system, the pump including an expandable housing having an outer surface, an inner surface, an expanded configuration, and a collapsed configuration. The pump may further include a valve member. In some variations, the valve member may be a valve cone including a flow control layer and a mesh layer coupled to the expandable frame. In other variations, the valve member may be a flexible diaphragm including a diaphragm body and a periphery disposed within the expandable housing, the flexible diaphragm having an extended configuration and a collapsed configuration. Once at the target location, the expandable housing may be expanded from the collapsed configuration to the expanded configuration, and the valve cone or flexible diaphragm contained therein may be linearly reciprocated to generate the filling stroke and the pumping stroke of the pumping cycle. When the pump further includes a cannula, the cannula may be advanced through the aortic valve and into the left ventricle of the patient. Non-limiting examples of target locations for the expandable housing and flexible diaphragm include the aortic arch, the descending aorta, the thoracic aorta, and the abdominal aorta.

[0203] In addition to the arterial vessels, the pump may be advanced and positioned within the venous circulatory system. For example, the expandable housing of the pump may be advanced within the inferior vena cava to a location between the hepatic vein and the right atrium of the heart. Once in this location, the pump may draw blood toward the heart to increase circulation from the lower extremities and from the liver. The pump may be positioned in various locations between the hepatic vein and the right atrium. In some variations, the expandable housing is positioned closer to the hepatic vein than to the right atrium.

[0204] The expandable housing and valve member (e.g., valve cone and flexible diaphragm) may be in their collapsed configuration within the outer and inner sheaths, respectively, during advancement within the vessel. In some variations, once the expandable housing is positioned at the target location, the outer sheath may be retracted, allowing the housing to expand from the collapsed configuration to the expanded configuration. In other variations, the expandable housing may be advanced out of the housing, for example, using a pusher, thereby allowing the housing to expand from the collapsed configuration to the expanded configuration. The inner sheath, which may be concentrically disposed about the valve cone or flexible diaphragm, may then be retracted, allowing the valve cone or diaphragm to expand from the collapsed configuration to the expanded or extended configuration. When the pump includes a support member, such as an expandable frame, removal of the inner sheath may also allow the frame to expand from the collapsed configuration to the expanded configuration. When the pump includes a support member, such as a tine support, removal of the inner sheath may also allow the tines to expand from a compressed configuration to an expanded configuration.

[0205] The pump may be reciprocated within the expandable housing under the force of a reciprocating actuator (e.g., a drive cable) to initiate a series of filling and pumping strokes. In variations where the valve member is a flexible diaphragm, during each filling stroke of the pump, the flexible diaphragm may collapse, allowing blood to flow past the diaphragm (with or without supporting tines) and fill the expandable housing. During each pumping stroke of the pump, the flexible diaphragm may return to its extended configuration, forcing blood out of the expandable housing. In variations where the valve member is a valve cone, including a flow control layer and a mesh layer, during each filling stroke of the pump, flaps in the flow control layer open, and openings in the mesh allow blood to flow through the valve cone and fill the expandable housing. During each pumping stroke of the pump, the flaps return to their closed configuration, supported by the mesh layer, and remain closed against the pressure of the blood as it is forced out of the expandable housing. The reciprocating motion of the drive cable and pulsatile pump may be controlled by a programmable linear motor controller to provide the desired blood flow and pressure characteristics. In some variations, the linear motor controller may be configured to control the pump via sensor (e.g., pressure transducer) feedback, as described in more detail herein.

[0206] During the pump stroke, contact between the periphery of the valve cone or flexible diaphragm and the inner surface of the expandable housing may be maintained so that a seal is created to prevent blood flow between the periphery and the inner surface. In addition, blood may be drawn into the expandable housing during the pump stroke. Depending on the variation of the pump used, blood may be drawn into the expandable housing from the left ventricle or the aorta. The pump stroke may generally push blood out of the expandable housing and into a portion of the aorta, for example the ascending aorta or the descending aorta. When the expandable housing and the flexible diaphragm are mounted outside the patient, blood may be pushed into the ascending aorta just above the aortic valve through a coaxial catheter coupled thereto. During the pumping cycle, the valve cone or flexible diaphragm may be collapsed into a collapsed configuration during the filling stroke and expanded into an expanded or extended configuration during the pump stroke.

[0207] The pump may be advanced and positioned in various portions of the patient's circulatory system. In one variation, the pump may be advanced until the expandable housing and the pulsatile portion of the pump (e.g., the flexible diaphragm with or without tines) are located in the left ventricle and the cannula extending from the proximal end of the expandable housing extends through the aortic valve. In this variation, blood may flow through the proximal inlet of the expandable housing to fill the expandable housing during the filling stroke (backward movement of the flexible diaphragm toward the foot). The blood then exits the distal outlet of the expandable housing to provide blood to the body during the pumping stroke (forward movement of the flexible diaphragm toward the head).

[0208] For example, as illustrated in FIG. 2, pump 10 may be advanced into the left ventricle in its collapsed configuration within the aorta of a patient. Heart 50 includes left ventricle 56 in fluid communication with ascending aorta 52 and descending aorta 51. Ascending aorta 52 further supports multiple arteries, such as arteries 53 (brachiocephalic artery), 54 (left common carotid artery), and 55 (left subclavian artery). In FIG. 2, pump 10 is advanced into the left ventricle through descending aorta 51 in the direction of arrow 35. As described above, pump 10 may include outer sheath 11 through which drive cable 40 may pass. Also, as described above, pump 10 may define end 12 within which bearing 13 may be supported. Expandable housing 25 (seen in more detail in FIG. 3) may be deployed from outer sheath 11 and may fixedly support bearing 13. A tine support 15 including a plurality of tines 20 may be coupled to an end of a drive cable 40 and captured within outer sheath 11 in the manner described above in FIG.

[0209] Once the pump 10 is positioned within the left ventricle 56, it assumes the operating position shown in Figure 3. Here, the expandable housing 25 has been expanded to its expanded configuration and is thus shown to include a distal inlet (mesh portion) 26 and a proximal outlet (mesh portion) 27. The proximal outlet 27 is provided at the end of a cannula (housing extension) 28, which extends from the expandable housing 25, through the aortic valve, and into the ascending aorta 52. In this configuration, blood is drawn from the left ventricle 56 into the expandable housing 25 during the filling stroke and moved out of the expandable housing 25 to the ascending aorta 52 and arteries 53, 54, and 55 in the direction of the arrows during the pumping stroke.

[0210] The pumping action of pump 10 may be initiated by activating linear motor 19 (seen in FIG. 1) to initiate the reciprocating action of tine support 15 (and plurality of tines 20) with a continuous force pushing and pulling flexible cable 40. The pumping action of pump 10 is described in more detail below in FIGs. 8 and 9. However, for now, it is sufficient to note that FIG. 3 generally illustrates the operation of pump 10 during a pump stroke, which is characterized by a pulling force on drive cable 40 and movement of tine support 15 in the direction indicated by arrow 36. Note that during this pump stroke, diaphragm 30 is extended to its fully open configuration, thus providing a driving force to the blood within expandable housing 25, pushing blood upward through cannula (housing extension) 28 and outward through proximal outlet (mesh portion) 27, generating blood flow through ascending aorta 52 and outwardly to the patient's body through arteries such as arteries 53, 54, and 55. With reference to FIG. 4 , note that a pushing force on drive cable 40 in the direction indicated by arrow 37 therein produces a fill stroke during which diaphragm 30 collapses and blood flows into expandable housing 25 through distal inlet 26.

[0211] With the cardiac assist pulsatile pump 10 remaining positioned within the left ventricle and aorta, and the expandable housing 25 remaining configured for operation, the pumping action of the pump 10 continues as the linear motor 19 (seen in FIG. 1) continues the reciprocating action of the tine support (and the plurality of tines 20) by the continued force of pushing and pulling the flexible cable 40. Again, it should be understood that the pumping action of the pump 10 is described in more detail below in FIGS. 8 and 9. However, for now, it is sufficient to note that FIG. 4 illustrates the operation of the pump 10 during a fill stroke, which is characterized by a pushing force on the drive cable 40 that moves the tine support 15 in the direction indicated by arrow 37. Note that during this fill stroke, the diaphragm 30 is partially collapsed, thus exerting a reduced force on the blood within the expandable housing 25. As a result, blood is able to flow inwardly through the distal inlet (mesh portion) 26 and fill the interior of the expandable housing 25. For purposes of illustration, turning momentarily back to Figure 3, recall that a pulling force on drive cable 40 in the direction indicated by arrow 36 therein produces a pumping stroke during which diaphragm 30 expands and blood flows outwardly from expandable housing 25. Thus, referring simultaneously to Figures 3 and 4, the pumping action of pump 10 can be illustrated by alternating pumping strokes, as shown in Figure 3, and filling strokes, as shown in Figure 4.

[0212] Some pump variations do not include a cannula extending from the expandable housing. For example, pump 100 of Figures 5, 6, and 7 is substantially the same as pump 10 of Figures 3 and 4 in both structure and function, except for the absence of cannula (extension) 28. In addition, as shown in Figures 18A and 18B, pump 700 does not include a cannula extending from either the proximal end 702 or the distal end 704 of the expandable housing 710, but is otherwise substantially the same as pump 100. Exemplary target locations for pumps 100 and 700 may be the thoracic aorta 706 (Figure 18A) or abdominal aorta 708 (Figure 18B). In Figure 5, blood from one portion of the aorta enters the expandable housing 60 via inlet 63 and is pumped to a second portion of the aorta in response to exiting from outlet 64 of the expandable housing 60. 18A, blood from one portion 716 of the thoracic aorta 706 is pumped to a second portion 718 of the thoracic aorta 706 in response to blood entering the expandable housing 710 via the inlet 712 and exiting the expandable housing 710 via the outlet 714. In FIG. 18B, blood from one portion 720 of the abdominal aorta 708 is pumped to a second portion 722 of the abdominal aorta 708 in response to blood entering the expandable housing 710 via the inlet 712 and exiting the expandable housing 710 via the outlet 714.

[0213] As an overview, Figures 5, 6, and 7 set forth sequential cross-sectional views of pulsatile pump 100 illustrating the transition of the pulsatile pump portion between its compact configuration utilized during catheter insertion and its expanded operating configuration utilized during pumping operations. Thus, Figure 5 shows a cross-sectional view of linear cardiac assist pump 100 in its collapsed configuration, while Figure 7 shows a cross-sectional view of pump 100 in its expanded operating configuration. Figure 6 sets forth a cross-sectional view of pump 100 at an intermediate point between the configurations shown in Figures 5 and 7.

[0214] Figures 8 and 9 depict cross-sectional views of pump 100 during operation. Figure 8 depicts a cross-sectional view of pump 100 during a filling stroke, while Figure 9 depicts a cross-sectional view of pump 100 during a pumping stroke. A series of filling and pumping strokes are repeatedly performed to produce a pulsatile pumping action as a linear motor (linear motor 19 seen in Figure 1) reciprocates drive cable 40, thereby reciprocating a pumping mechanism within pump 100.

[0215] With specific reference to FIG. 8, the pump 100 includes an expandable housing 60 having an end 62 that supports a bearing 13 and an inlet (scaffolding portion) 63. The expandable housing 60 further includes a chamber 61 and an outlet (scaffolding portion) 64. The chamber may be formed by embedding (e.g., overmolding) a portion of the scaffolding of the expandable housing 60 in a polymer layer or by bonding a fabric layer to the scaffold, as described above. A tine support 15 is slidably received within the bearing 13 and may be joined to an inner end of the drive cable 40. The tine support 15 supports a plurality of tines 20 and a flexible diaphragm 30. The tine support 15 may define a plurality of outwardly extending spline ribs between which spline grooves are formed. The spline grooves provide a blood flow path by which blood may flow past the tine support 15.

[0216] As mentioned, FIG. 8 illustrates the fill stroke during operation of pump 100. Thus, a reciprocating force applied to drive cable 40 causes tine support 15 to move in the direction indicated by arrow 38. Because blood is present in chamber 61, movement of tine support 15 in the direction indicated by arrow 38 causes a force against the rear side of diaphragm 30 which in turn causes it to flex in the manner shown. Flexion of diaphragm 30 away from its outwardly extended position (seen in FIG. 9) allows blood flow around tines 20 and diaphragm 30 in chamber 61. This provides for filling of chamber 61, with blood being drawn through inlet portion 63 and bearing 13. Once tine support 15 reaches the end of its fill stroke, the driver described above applies a pulling force to drive cable 40, commencing the pump stroke shown in FIG. 9.

[0217] With specific reference to FIG. 9, pump 100 includes an expandable housing 60 having an end 62 that supports bearing 13 and an inlet (scaffolding portion) 63. Expandable housing 60 further includes a chamber 61 and an outlet (scaffolding portion) 64. Tine support 15 is slidably received within bearing 13 and is coupled to an inner end of drive cable 40. Tine support 15 includes a plurality of tines 20 and a flexible diaphragm 30. Tine support 15 defines a plurality of outwardly extending spline ribs having spline grooves formed therebetween. The spline grooves provide a blood flow path by which blood can flow past tine support 15.

[0218] As mentioned, FIG. 9 illustrates a pump stroke during operation of pump 100. Thus, a reciprocating force applied to drive cable 40 moves tine support 15 in the direction indicated by arrow 39. Because blood is present in chamber 61, movement of tine support 15 in the direction indicated by arrow 39 causes a force against the front side of diaphragm 30, which in turn pushes diaphragm 30 against tines 20 in the extended position shown. Extension of diaphragm 30 to its outwardly extended position pushes blood from chamber 61 in front of diaphragm 30 as diaphragm 30 moves in the direction indicated by arrow 39. This in turn creates a blood flow outwardly from chamber 61 through outlet 64. Once tine support 15 reaches the end of its pump stroke, the drive arrangement described above applies a pushing force to drive cable 40 to initiate the next fill stroke shown in FIG. As the drive device described above reciprocates, alternating pushing and pulling forces are generated on the cable 40, corresponding to successive filling and pumping strokes of the pump 100, which produces pulsatile blood flow.

[0219] As explained above, the expandable housing in some variations may include a plurality of openings and a skirt coupled to the expandable housing. In this case, blood exiting the openings may be directed by the skirt in a retrograde direction toward the patient's heart during the pump stroke. Retrograde blood flow may help provide proper perfusion of arteries branching from the aortic arch, such as the carotid and subclavian arteries. The ability to maintain proper perfusion of the subclavian artery may prevent backflow from the vertebral basilar artery into the subclavian artery, a phenomenon known as "subclavian steal." For example, referring to FIG. 21, the pump 800 may draw blood from the left ventricle 814 through an inlet 812 provided at the distal end 824 of a cannula 810, which may extend from the expandable housing 802. From the inlet 812, blood may flow in the direction of arrow 830 and fill the expandable housing 802. During a pump stroke, blood from the expandable housing 802 may generally be moved in the direction of arrow 826 toward the outlet 808. However, as blood is moved past the plurality of openings 804, a first portion of the blood may be pushed through the openings 804 and then directed by the skirt 806 back toward the heart in the direction of arrow 828 to perfuse the blood vessels 818 branching off the aortic arch. The portion of the blood that is not pushed out of the expandable housing through the plurality of openings 804 and remains within the expandable housing 802 (a second portion) is pushed through the outlet 808 toward the feet and to the remainder of the body.

[0220] The length of the skirt may be adjusted to achieve a predetermined amount of retrograde blood flow toward the patient's heart. Alternatively, the number of openings may be adjusted to achieve a predetermined amount of retrograde blood flow toward the patient's heart. The diameter of the openings may also be adjusted to achieve a predetermined amount of retrograde blood flow toward the patient's heart. The combination of the number of openings and the opening diameter may provide an amount of open surface area on the expandable housing for retrograde blood flow. Thus, adjustment of any one or combination of the aforementioned features may be utilized such that about 60% of the blood from the pump stroke flows in a retrograde direction toward the patient's heart, about 50% of the blood from the pump stroke flows in a retrograde direction toward the patient's heart, or about 40% of the blood from the pump stroke flows in a retrograde direction toward the patient's heart.

[0221] In some variations, the skirt may be configured to adjust the amount of open surface area for retrograde flow by adjusting the number of openings that are patent (open) and closed. For example, a tether may be coupled to the skirt and configured to open and close the skirt relative to the expandable housing, similar to the way a noose can be tightened and loosened. The amount of opening or closing may be adjusted, for example, using a rotatable dial located on a console external to the patient. In general, a larger amount of open surface area may provide more retrograde blood flow toward the patient's head and heart, and a smaller amount of open surface area may provide more antegrade blood flow to the body.

[0222] Other methods for pumping blood may include advancing a pump to a target location within a patient's aorta, such as the thoracic aorta or abdominal aorta, the pump having a fill stroke and a pump stroke, drawing a fill volume of blood into the pump during the pump stroke, and pushing an exit volume of blood out of the pump during the pump stroke, the exit volume comprising a first portion of blood and a second portion of blood. The fill stroke may draw blood from the patient's left ventricle. Additionally, the first portion of blood may be pumped in a retrograde direction toward the patient's head, and the second portion of blood may be pumped in an antegrade direction. The second portion of blood may be about 60% of the exit volume, about 50% of the exit volume, or about 40% of the exit volume.

[0223] When the pump is located external to the patient, the method for pumping blood may include accessing the patient's circulatory system with a coaxial cable. The external pump may include the same valve member, e.g., valve cone or flexible diaphragm, as the internal pump located in the vessel or ventricle, but the housing may not be expandable. The valve cone or flexible diaphragm contained within the expandable housing may include a body and a periphery. The flexible diaphragm may have an extended configuration and a collapsed configuration, and the valve cone may have an expanded configuration and a collapsed configuration. The external pump may be located within a console that includes a user interface. The coaxial catheter may include an inflow lumen and an outflow lumen. The coaxial catheter may be coupled to the external pump at one end, and the other end may be inserted and advanced into the patient.

[0224] Access to the circulatory system with the coaxial catheter may be obtained from any suitable artery or vein, for example, the femoral, subclavian, carotid, or jugular artery. Once access is obtained, the coaxial catheter may be advanced to a target location within the circulatory system and the flexible diaphragm may be linearly reciprocated within the housing to generate the fill stroke and pump stroke of the pumping cycle. During the pump stroke, contact between the periphery of the valve cone or flexible diaphragm and the inner surface of the housing may be maintained to create a seal therebetween and prevent blood from flowing around the valve cone or flexible diaphragm. The seal may help to generate and maintain the force of the pump stroke and minimize red blood cell damage that may occur from blood flowing between the space that exists between the periphery and the inner surface. The methods described herein may include advancing the coaxial catheter to various target locations within the patient. For example, the target location for the inflow lumen of the coaxial catheter may be the left ventricle of the patient and the target location for the outflow lumen of the coaxial catheter may be above the aortic valve of the patient.

[0225] For example, as shown in FIGURE 23A, an external pump 1000 is coupled to a coaxial catheter 1006 by inlet and outlet tubing 1016. The coaxial catheter 1006 includes an inflow lumen 1018 and an outflow lumen 1020, as shown in the close-up view provided in FIGURE 23B. Access to the circulatory system by the coaxial catheter 1006 is via the femoral artery 1026. Once access is obtained, the coaxial catheter 1006 is advanced into the left ventricle 1024. More specifically, as shown in the close-up view of FIGURE 23C, the distal end of the coaxial catheter 1006 is advanced until the inflow lumen 1018 is within the left ventricle and the outflow lumen 1020 is seated above the aortic valve. In FIG. 23C, blood is shown being pulled from the left ventricle 1024 into an inflow lumen 1018 at the pump intake end and pushed out an outflow lumen 1020 at the pump exhaust end just above the aortic valve 1022. The pump 1000 is also coupled to a linear motor drive 1002 and a linear motor controller 1004 in a console 1008. The console 1008 also includes a power supply 1010, a battery 1012, and a user interface 1014. The linear motor controller 1004 may be configured to control the speed of the pump 1000 via pressure transducer feedback. For example, a pressure transducer (not shown) may be mounted in or on the inflow lumen 1018 and another pressure transducer may be mounted in or on the outflow lumen 1020. In some variations, two pressure transducers may be mounted in or on the inflow and outflow lumens for redundancy in case one fails. The controller may be configured to have predetermined high and low blood pressure set points. When measurements from the pressure transducer indicate that the blood pressure has fallen below the low set point, the controller 1004 will increase the speed of the linear reciprocating motion, and if it is too high (e.g., above the high set point), the controller 1004 will slow down the speed of the linear reciprocating motion, thereby reducing the flow and reducing the blood pressure back within the target range.

[0226] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that specific details are not required to practice the invention. Thus, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously, many modifications and variations are possible in light of the above teachings. The embodiments have been chosen and described in order to explain the principles of the invention and its practical application, thereby enabling those skilled in the art to utilize the invention and its various embodiments with various modifications as suited to the particular use envisaged.

Claims

1. 1. A pump for assisting blood circulation, comprising: a housing having an interior surface and an extension structure; a valve member comprising an umbrella structure disposed within the expandable housing, the umbrella structure comprising a membrane having a periphery and a plurality of struts, each of the plurality of struts having a distal end, the umbrella structure having an expanded configuration and a collapsed configuration; A pump comprising:

2. The pump of claim 1 , further comprising an actuator coupled to the umbrella structure, the actuator configured to linearly reciprocate the umbrella structure within the housing.

3. The pump of claim 2 , wherein the pump has a fill stroke and a pump stroke, the peripheral edge of the membrane configured to maintain contact with the inner surface of the housing during the pump stroke.

4. The pump of claim 1 , wherein the membrane comprises an elastomeric polymer.

5. The pump of claim 4 , wherein the elastomeric polymer comprises a silicone, a polyester, a polyurethane, a fluoropolymer, or a combination thereof.

6. The pump of claim 5 , wherein the fluoropolymer comprises polytetrafluoroethylene (PTFE) or expanded polytetrafluoroethylene (ePTFE).

7. The pump of claim 1 , wherein the plurality of struts comprises between 6 struts and 10 struts.

8. The pump of claim 1 , wherein at least one strut of the plurality of struts comprises a bend.

9. The pump of claim 8 , wherein the bend comprises a bend angle ranging from about 5 degrees to about 15 degrees.

10. The pump of claim 1 , wherein each strut of the plurality of struts has a strut angle ranging from about 30 degrees to about 60 degrees.

11. The pump of claim 1 , wherein a distal end of each of the plurality of struts comprises an opening.

12. The pump of claim 1 , wherein a distal end of each of the plurality of struts comprises a circular or oval shape.

13. The pump of claim 1 , wherein the plurality of struts are configured to be inverted about an anchor.

14. The pump of claim 1, wherein the umbrella structure further comprises an anchor attached to the proximal end of each of the plurality of struts.

15. The pump of claim 1, wherein at least a portion of the housing or the valve member is provided with a polymer coating.

16. The pump of claim 15, wherein the polymer coating comprises polytetrafluoroethylene (PTFE) or expanded polytetrafluoroethylene (ePTFE).

17. A pump as described in claim 1, wherein the thickness of the peripheral edge is greater than the thickness of the body.

18. The pump of claim 1, wherein the plurality of struts comprise stainless steel, nickel, titanium, or alloys thereof.

19. The pump of claim 1, wherein the periphery has a thickness ranging from about 0.20 mm to about 1.5 mm.

20. The pump of claim 1, further comprising a cannula.

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