Interventional catheter pump and pump body thereof

Abstract

The invention discloses an intrusive catheter pump capable of stably maintaining a pump gap and a pump body thereof. The pump body comprises a pump shell with a blood inlet and a blood outlet, and an impeller accommodated in the pump shell and used for providing power for flowing of blood; the pump shell at least comprises a covering film for limiting a blood flowing channel; wherein the pump body comprises a radial folding state and a radial unfolding state, and the pump body can be operably switched between the radial folding state and the radial unfolding state; compared with an unstressed state, the covering film is configured to be free of tensile deformation when the pump shell is in a radial expansion state.

Description

Technical Field

[0001] This invention relates to the field of medical devices, particularly to a cardiac assist device, and more particularly to an interventional catheter pump and its pump body. Background Technology

[0002] An interventional catheter pump device (referred to as a blood pump) can pump blood. Taking left ventricular assist as an example, current technology generally places the pump of the interventional catheter pump device in the left ventricle of the subject's body. A flexible shaft drives the impeller of the pump to rotate, and a motor drives the flexible shaft to transmit power to the pump.

[0003] Existing catheter pumps are designed to ensure stable contraction and expansion, enabling insertion into a patient's blood vessel and subsequent expansion. During compression and expansion, the rotor (e.g., impeller) and housing typically deform accordingly. The challenge here is to maintain the pump clearance—the gap between the radially outer end of the impeller and the inner wall of the housing—at a minimum and keep it stable to optimize pump efficiency. Summary of the Invention

[0004] In view of the above-mentioned shortcomings, one object of the present invention is to provide an interventional conduit pump and its power transmission assembly capable of stably maintaining pump clearance.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An interventional catheter pump body is disclosed, capable of pumping blood to a desired location on the heart; comprising: a pump housing having a blood inlet and a blood outlet; an impeller housed within the pump housing and used to power blood flow; the pump housing includes at least a membrane defining a blood flow channel. The pump body includes a radially folded state and a radially expanded state, operable to switch between the two states. The membrane is configured not to undergo tensile deformation in the radially expanded state compared to an unstressed state.

[0007] An interventional catheter pump body is disclosed, capable of delivering blood to a desired location on the heart. It includes: a pump housing having a blood inlet and a blood outlet; an impeller housed within the pump housing and used to power blood flow; the pump housing includes at least a membrane defining a blood flow channel. The pump body includes a radially folded state suitable for delivery within the subject's vascular system, a naturally unfolded state corresponding to the impeller not rotating, and an operating state corresponding to the impeller rotating. During the transition from the naturally unfolded state to the operating state, the blood back pressure applied to the membrane due to the impeller rotation causes at least partial flattening of the membrane's folds.

[0008] Preferably, the flattening of the folds increases the diameter of the coating.

[0009] Preferably, the flattening of the wrinkles results in an increase in the diameter of the coating of no more than 3%.

[0010] Preferably, during the process from the naturally unfolded state to the working state, the coating process includes at least one sub-process in which the diameter does not increase.

[0011] Preferably, the membrane is configured to not undergo tensile deformation when the pump housing is in its naturally unfolded state or in operation, compared to the unstressed state.

[0012] Preferably, the pump casing further includes a support member for supporting the unfolded membrane; the radial unfolded state includes the natural unfolded state corresponding to the impeller not rotating; the membrane is configured such that the critical stress causing it to undergo tensile deformation is greater than or equal to the force applied to it by the support member when the pump casing is in the natural unfolded state.

[0013] Preferably, the radially expanded state also includes the working state corresponding to the impeller rotation; the critical stress at which the membrane undergoes tensile deformation is greater than or equal to the force exerted on the membrane by the blood back pressure caused by the impeller rotation when the pump body is in maximum working condition.

[0014] Preferably, the material strength of the membrane itself is sufficient to resist the outward expansion force of the supporting member, so that the circumferential tensile deformation of the membrane is 0 when the pump casing switches from a radially folded state to a naturally unfolded state.

[0015] Preferably, the material strength of the membrane itself is sufficient to resist the force exerted on it by the blood back pressure caused by the rotation of the impeller, so that the circumferential tensile deformation of the membrane is 0 when the pump housing switches from the naturally unfolded state to the working state.

[0016] Preferably, the diameter of the membrane when the pump body is in the working state is larger than the diameter when the pump body is in the naturally unfolded state.

[0017] Preferably, when the pump is in operation, the blood back pressure applied to the membrane caused by the rotation of the impeller causes the wrinkles of the membrane to be at least partially flattened.

[0018] An interventional catheter pump body is disclosed, capable of delivering blood to a desired location on the heart; comprising: a pump housing having a blood inlet and a blood outlet; an impeller housed within the pump housing and used to power blood flow; the pump housing includes at least a membrane defining a blood flow channel. The pump body includes a radially folded state suitable for delivery in the subject's vascular system, a naturally unfolded state corresponding to the impeller not rotating, and an operating state corresponding to the impeller rotating. The diameter of the membrane in the operating state is larger than the diameter of the pump body in the naturally unfolded state.

[0019] Preferably, the pump housing further includes a support member for supporting the unfolded membrane; in the naturally unfolded state, the support member is radially constrained by the membrane and is not fully unfolded.

[0020] Preferably, the pump housing further includes a support member for supporting the unfolded membrane; in the naturally unfolded state, the support member has a contact support portion that contacts the membrane. In the operating state, at least a portion of the contact support portion is spaced apart from the membrane.

[0021] Preferably, the membrane includes a cylindrical section and a proximal conical section disposed at the proximal end of the cylindrical section. A blood inlet extends from the proximal conical section into the cylindrical section, and a portion of the blood outlet is located in the proximal conical section, while another portion of the blood outlet is located in the cylindrical section. At least a portion of the axial length of the blood inlet gradually decreases in circumferential width as it extends from its distal end to its proximal end. Alternatively, the length of the blood outlet portion in the proximal conical section is greater than its length portion in the cylindrical section.

[0022] Preferably, the coating material is TPU, PTFE, or PEBAX.

[0023] An interventional duct pump includes: a duct, a drive shaft passing through the duct, a power assembly connected to the proximal end of the drive shaft, and a pump body as described in any of the above embodiments; the impeller of the pump body is connected to the distal end of the drive shaft.

[0024] The duct pump and pump body provided in this embodiment of the invention have a membrane that does not undergo tensile deformation in the radially expanded state, and the membrane has strong resistance to deformation. Furthermore, in the radially expanded state, it can stably constrain and maintain the shape of the supporting components, maintain the pump clearance, and ensure optimal pump efficiency. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of an interventional catheter pump structure provided in one embodiment of the present invention;

[0026] Figure 2 yes Figure 1 Enlarged view of part A;

[0027] Figure 3 yes Figure 2 A three-dimensional image;

[0028] Figure 4 yes Figure 3 Partial cross-sectional view;

[0029] Figure 5 yes Figure 1 A three-dimensional view of the coating;

[0030] Figure 6 yes Figure 5 The front view;

[0031] Figure 7 This is a schematic diagram of the pump body of an interventional catheter pump provided in another embodiment of the present invention;

[0032] Figure 8This is a graph showing the diameter variation of six different pump bodies under fluid back pressure according to the present invention.

[0033] Explanation of reference numerals in the attached drawings: 1. Pump body; 2. Conduit; 3. Power assembly; 4. Coupler; 5. Impeller; 6. Impeller shaft; 7. Proximal bearing chamber; 8. Flexible support component; 10. Pump casing; 11. Membrane; 12. Support component; 13. Blood inlet; 14. Blood outlet; 15. Distal bearing chamber; 16. Connecting ring; 17. Proximal end of membrane; 18. Distal end of membrane; 19. Connecting strip; 20. Front blood outlet; 21. Rear blood outlet; 50. Blade; 51. Hub; 121. Proximal end of conical support; 123. Distal end of conical support; 122. Cylindrical support section; 125. Ring; 110. Cylindrical section; 111. Proximal conical section. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0035] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or may be interposed with another element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] The terms "proximal" and "distal," and "anterior" and "posterior" as used in this invention are relative to the clinician operating the interventional catheter pump. The terms "proximal" and "posterior" refer to the portion relatively close to the clinician, while the terms "distal" and "anterior" refer to the portion relatively far from the clinician. For example, the external portion is located at the proximal and posterior ends, while the internal portion of the interventional procedure is located at the distal and anterior ends.

[0038] Please see Figures 1 to 6 The interventional catheter pump of this invention includes: a pump body 1, a catheter 2, and a power assembly 3. The power assembly 3 is disposed at the proximal end of the catheter 2, connected to the catheter 2 via a coupling body 4, and connected to the pump body 1 via a flexible shaft passing through the catheter 2.

[0039] Pump 1 can be delivered to the desired location on the heart to pump blood. The power source of pump 1 can be an external motor or an internal motor, and the present invention does not impose any particular limitation. In an embodiment with an external power source, pump 1 can be connected to an external motor via a conduit 2. The conduit 2 houses a flexible shaft and transmits power to the impeller 5 of pump 1.

[0040] In the embodiment where the power source is built-in, the built-in motor can be a hydraulic motor or an electric motor (e.g., an electric motor). The power component 3 can be sent into the body via the conduit 2 and kept in a position close to the pump body 1, thereby reducing the length of the connecting shaft between the two and reducing problems such as friction and heat caused by the rotation of a long shaft.

[0041] The pump body 1 includes a pump housing 10 having a blood inlet 13 and a blood outlet 14, and an impeller 5 housed within the pump housing 10. The impeller 5 is used to provide power for the flow of blood, and the pump housing 10 includes at least a membrane 11 defining a blood flow channel.

[0042] The pump body 1 includes a radially folded state and a radially expanded state. The pump casing 10 can be operatively switched between the radially folded and radially expanded states. Compared to the unstressed state, the membrane 11 does not undergo tensile deformation when the pump casing is in the radially expanded state.

[0043] The pump housing 10 also includes a support member 12 for supporting the unfolded membrane 11. The support member 12 may be integrally disposed inside the membrane 11 or even separately disposed outside the membrane 11 to support the membrane 11.

[0044] When the pump casing 10 is in a radially expanded state, the supporting member 12 contacts the inner wall of the membrane 11 and expands radially to support and expand the membrane 11. In this case, the membrane 11 does not undergo tensile deformation in the unstressed state compared to the radially expanded state when the pump casing 10 is unstressed.

[0045] The radially expanded state of the pump casing 10 when it is not under force is the natural expanded state when the impeller 5 is not rotating.

[0046] The radially expanded state includes the natural expanded state when the impeller 5 is not rotating. The critical stress at which the membrane 11 undergoes tensile deformation is greater than or equal to the force applied to it by the support member 12 when the pump casing is in the natural expanded state. Thus, when only the support member 12 applies a radial supporting force to the membrane 11, since the critical stress for tensile deformation of the membrane 11 is not reached, the membrane 11 does not undergo tensile deformation in the natural expanded state supported by the support member 12.

[0047] The radially expanded state also includes the working state when the impeller 5 rotates. To ensure the toughness of the membrane 11, provide a more stable pump clearance, and stabilize pump efficiency, the critical stress at which the membrane 11 undergoes tensile deformation is greater than or equal to the force exerted on the membrane 11 by the blood back pressure caused by the rotation of the impeller 5 when the pump body 1 is in maximum operating condition.

[0048] The maximum operating condition of pump body 1 corresponds to the maximum speed of impeller 5 under rated power. At this time, the pump flow rate corresponds to the maximum value, and the blood back pressure is also at its maximum value. In this embodiment, the maximum value of blood back pressure still does not exceed the critical stress point for tensile deformation of membrane 11. Therefore, even when the impeller is rotating, membrane 11 will not undergo tensile deformation to avoid changes in pump clearance and stabilize pump efficiency.

[0049] It should be clarified that the tensile deformation of the coating 11 in this invention refers to the circumferential length deformation of the coating 11. When subjected to radial force, this manifests as an increase in the circumferential length (circumference). However, if the coating 11 itself has wrinkles, the flattening of the wrinkles due to the expansion of the supporting member 12 does not constitute stretching of the coating 11.

[0050] The wrinkles in the coating 11 are mostly caused by folding. Due to the radial constraint of the folded sheath, the coating 11 is forcibly compressed and folded, resulting in wrinkles. Of course, this does not rule out other factors that may cause wrinkles in the coating 11. For example, they may be formed during manufacturing, or caused by deformation during placement, or during testing, etc. Wrinkles can take the form of creases or (fine) wrinkles.

[0051] The pump body 1 has an interventional configuration and an operational configuration. In the interventional configuration, the pump housing 10 and impeller 5 are radially folded, allowing the pump body 1 to intervene in and / or deliver blood within the vascular system of the subject with a smaller first outer diameter. In the operational configuration, the pump housing 10 and impeller 5 are radially extended, allowing the pump body 1 to pump blood at a desired location (e.g., the left ventricle) with a second outer diameter larger than the first outer diameter.

[0052] like Figure 4 As shown, the impeller 5 includes a hub 51 connected to the distal end of the drive shaft and blades 50 supported on the outer wall of the hub 51. The blades 50 can be helical blades, thereby driving blood flow through rotation.

[0053] In the intervention configuration of the pump body 1, the blade 50 is wrapped around the outer wall of the hub 51 and at least partially contacts the inner wall of the pump casing 10. In the working configuration of the pump body 1, the blade 50 extends radially outward from the hub 51 and is spaced apart from the inner wall of the pump casing 10, so as to avoid the pump casing 10 affecting the rotation of the blade 50 and to avoid the rotation of the blade 50 damaging the pump casing 10.

[0054] In this embodiment, when the catheter pump is in use, the pump body 1 and part of the catheter 2 (specifically, the front end portion of the catheter 2) are inserted into and held in the subject's body. The size of the pump body 1 and part of the catheter 2 needs to be as small as possible. Therefore, the axial projected area of ​​the pump body 1 and part of the catheter 2 is smaller than the axial projected area of ​​other components, including the power assembly 3 (e.g., motor) of the pump body 1.

[0055] Therefore, the smaller size of the pump body 1 and part of the catheter 2 can reduce the patient's discomfort and minimize complications caused by excessively large interventional sizes during insertion and retention within the patient. Other parts of the power assembly 3 can have relatively larger dimensions to meet structural design requirements.

[0056] This catheter pump can replace blood in the heart, pumping blood from the left ventricle into the aorta to support blood circulation, reduce the workload on the subject's heart, or provide additional continuous pumping support when the heart's pumping capacity is insufficient. Of course, this catheter pump can also be placed in the desired location in the body, such as inside a blood vessel or other organ, via interventional surgery to pump blood or body fluids.

[0057] In this embodiment, the material strength of the membrane 11 itself is sufficient to resist the outward expansion force of the supporting member. Therefore, the circumferential tensile deformation of the membrane 11 is 0 when the pump housing 10 switches from the radially folded state to the naturally unfolded state, and no circumferential tensile deformation occurs.

[0058] Furthermore, the material strength of the membrane 11 itself is sufficient to resist the force exerted on it by the blood back pressure caused by the rotation of the impeller 5, so that the circumferential tensile deformation of the membrane 11 is 0 when the pump housing switches from the naturally unfolded state to the working state.

[0059] The coating 11 is made of TPU (thermoplastic polyurethane elastomer rubber), PEBAX, or PTFE (polytetrafluoroethylene). Preferably, the coating 11 is made of a block polyetheramide resin material such as PEBAX. The coating 11 does not lose mechanical properties under repeated deformation, is fatigue resistant, and has good resilience and elastic recovery properties as well as precise dimensional stability. Therefore, it does not undergo tensile deformation under the support of the support member 12, thus stably maintaining the pump clearance.

[0060] The membrane 11 bears and resists the radial expansion force of the support member 12 by its own material, and does not produce tensile deformation when the pump housing 10 is in a naturally unfolded state. The tensile deformation is circumferential tensile deformation.

[0061] Understandably, the inner diameter or cross-sectional area of ​​the membrane 11 remains the same in its unstressed state compared to its naturally unfolded state. The membrane 11, in the unstressed state of the pump casing 10, is a cylindrical structure unsupported by the supporting member 12. Similarly, it can be understood that the membrane 11, in its naturally unfolded state compared to its state when supported by the member 12 expanding outwards, does not undergo tensile deformation; the tensile deformation is zero.

[0062] The unforced condition in the radially expanded state (naturally expanded state) is relative to the condition where the impeller 5 rotates and drives the fluid (working state). When the impeller 5 rotates and drives the blood flow, the blood will also generate a certain radial expansion force (fluid back pressure) on the membrane 11.

[0063] When the diaphragm 11 is in a radially expanded state without being subjected to force by the pump housing 10, that is, when only the expansion force is applied to the diaphragm 11 by the support member 12, the diaphragm 11 will not undergo tensile deformation and has better resistance to deformation. Therefore, it can better maintain its shape, maintain the pump clearance, and maintain pump efficiency during the pumping process.

[0064] Furthermore, the membrane 11 does not undergo tensile deformation in the radially expanded state, thus the membrane 11 has strong resistance to deformation. In this way, in the radially expanded state, it can stably constrain and maintain the shape of the support member 12, maintain the pump clearance, and keep the pump body 1 at optimal pump efficiency.

[0065] Following the above description, the pump body 1 includes a radially folded state suitable for delivery in the subject's vascular system, a naturally unfolded state when the impeller 5 is not rotating, and an operating state when the impeller 5 is rotating. During the process of switching the pump body 1 from the naturally unfolded state to the operating state, the blood back pressure applied to the membrane 11 caused by the rotation of the impeller 5 causes the folds of the membrane 11 to be at least partially flattened.

[0066] The flattening of the wrinkles increases the diameter of the coating 11, and the increase in the diameter of the coating 11 does not exceed 3%, further does not exceed 2%, and even does not exceed 1%.

[0067] The aforementioned diameter increase rate is the rate of change of the diameter of the membrane 11 in the pump housing 10 in its naturally unfolded state compared to its working state. This diameter increase rate depends on the number and degree of undulation of the folds in the membrane 11, and further on the flexibility of the material of the membrane 11.

[0068] Specifically, the flexibility of the coating material 11 largely determines the number and degree of folds. That is, the less flexible the coating material 11, the more folds and the greater the degree of folds; when the folds are smoothed out, the increase in the diameter of the coating material 11 will be closer to 3%. Conversely, the more flexible the coating material 11, the fewer folds and the smaller the degree of folds; when the folds are smoothed out, the increase in the diameter of the coating material 11 will deviate further from 3%.

[0069] Therefore, in certain scenarios that cannot be explicitly ruled out, where the selected coating material 11 has particularly soft characteristics and thus has very few wrinkles, the contribution of wrinkle smoothing to the increase in the diameter of the coating 11 may be close to 0.

[0070] The membrane 11 is an integrally molded structure. The distal end 19 of the membrane 11 has a distal opening, which is circular and is unfolded by the support member 12 to form the blood inlet 13 of the pump housing 10 together with the support member 12. The distal end 19 of the membrane 11 is also provided with a connecting strip 19, the distal end of which is fixedly connected to the distal bearing chamber 15.

[0071] With the membrane 11 in a radially expanded state, the connecting strip 19 is roughly in a taut and stretched state. The proximal and distal ends of the membrane 11 are fixed by the connecting strip 19 and the connecting ring 16 of the distal end 18 of the membrane 11, thereby keeping the membrane 11 in an overall straight state in the axial direction, providing a continuous and stable rotational pumping space for the impeller 5.

[0072] Of course, in other embodiments, the distal end 19 of the membrane 11 can also be fixedly connected to the support member 12. For example, the inner wall of the distal end 19 of the membrane 11 is adhered to the outer wall of the support member 12, and expands and contracts together with the support member 12.

[0073] In its naturally unfolded state, the pump casing 10 has a contact support portion that contacts the membrane 11. Specifically, the support member 12 includes a conical support proximal end 121, a conical support distal end 123, and a cylindrical support segment 122 located between the conical support proximal end 121 and the conical support distal end 123. At least a portion of the axial length of the cylindrical support segment 122 constitutes the contact support portion.

[0074] The membrane 11 is fitted over the cylindrical support section 122 and is supported by the cylindrical support section 122 to form a stable cylindrical pump casing 10. The distal end 19 (end face) of the membrane 11 does not extend beyond the cylindrical support section 122.

[0075] The radially deployed state of the pump casing 10 forms the working configuration. In the working configuration, there are two states: one where the impeller 5 rotates and drives the blood flow (working state) and another where the impeller 5 is stationary (naturally deployed state). Due to the different states of the blood (stationary and flowing), the forces exerted on the membrane 11 are different. Furthermore, in the state where the impeller 5 rotates and drives the blood flow, there is not only a supporting force from the supporting member 12 on the membrane 11, but also a radial pushing force (fluid back pressure) on the membrane 11 caused by the blood being driven by the impeller 5.

[0076] Therefore, compared to the non-working state (natural unfolding state) of the coating 11, when the impeller 5 is in a high-speed working state (thousands or even tens of thousands of revolutions per minute or more), the coating 11 is stretched to a certain extent in the circumferential direction because the wrinkles are flattened. This stretching is caused by the flattening of the wrinkles, but the coating 11 itself does not undergo circumferential stretching deformation.

[0077] The diameter of the membrane 11 when the pump body 1 is in the working state is larger than the diameter when the pump body 1 is in the naturally unfolded state. When the pump body 1 is in the naturally unfolded state, the diameter of the membrane 11 is a first diameter. When the pump body is in the working state, the diameter of the membrane 11 is a second diameter. The second diameter is larger than the first diameter.

[0078] The diameter is the diameter of the internal cavity of the membrane 11. In the working state, due to the presence of fluid back pressure, at least some of the wrinkles of the membrane 11 are flattened, making the cross-sectional shape of the internal cavity of the structure more circular and the inner wall of the membrane 11 smoother, thereby increasing the diameter of the membrane 11 (the diameter of the cavity of the structure).

[0079] Specifically, when the pump housing 10 is in the operating state, the blood back pressure applied to the membrane 11 caused by the rotation of the impeller 5 causes the wrinkles of the membrane 11 to be at least partially flattened. During the process of the pump body 1 switching from the naturally unfolded state to the operating state, the blood back pressure applied to the membrane 11 caused by the rotation of the impeller 5 causes the wrinkles of the membrane 11 to be at least partially flattened, and the flattening of the wrinkles causes the increase in the diameter of the membrane 11 to not exceed 3%.

[0080] The rate of increase of the diameter is Figure 8 The diameter changes of the six groups of membranes 11 (where 1#-A to 3#-C represent different membrane names) under different back pressures can be observed. Each curve shows two pressure endpoints and the diameter of the membrane 11 at a roughly intermediate pressure. It can be seen from each curve that as the back pressure increases, the circumferential length of the membrane 11 elongates to a certain extent, but the increase in diameter is within 0.1 mm.

[0081] It should be noted that during the transition of the pump casing 10 from its naturally unfolded state to its working state, there is at least one sub-process in which the diameter of the membrane 11 does not increase. During the test, as the back pressure increases, the diameter of the membrane 11 sometimes remains unchanged or even decreases within a certain pressure range.

[0082] The reason for the aforementioned process where the diameter does not increase is that, due to the presence of wrinkles, the coating 11, in its naturally unfolded state, exhibits a cross-sectional shape that is nearly circular but not strictly circular. Wrinkles include radially inward depressions and may also include radially outward protrusions. If the selected diameter measurement points are two protrusion points, the initially measured diameter will be larger. However, after the wrinkles are flattened, the protrusions are flattened, leading to a phenomenon where, although the back pressure increases, the diameter decreases.

[0083] This further or indirectly proves that the circumferential elongation of the coating 11 in this invention is due to the flattening of the wrinkles rather than stretching deformation. This is because stretching deformation leads to a continuous increase in diameter, rather than a constant or decreasing diameter.

[0084] In one embodiment, when the impeller 5 rotates to drive blood flow, at least a portion of the contact support (cylindrical support section 122) of the pump housing 10 is separated from the membrane 11. Under the action of fluid back pressure, some of the wrinkles on the membrane 11 further flatten, and the inner diameter increases until it separates from the contact support. The membrane 11 itself is strong and tough, which limits the occurrence of tensile deformation. The further flattening of the wrinkles causes the membrane 11 to elongate circumferentially, but the change in elongation rate is less than 3%. The change in circumferential elongation is small, so that the gap between the impeller 5 and the membrane 11 can still be maintained in the working state, and the pump efficiency can be kept stable.

[0085] During the transition of the pump casing 10 from a radially folded state to a radially unfolded state, relative movement is permitted between the contact support and the membrane 11, and the location where the membrane 11 contacts the contact support, such as the cylindrical support section 122, is allowed to change. The relative position of the support member 12 and the membrane 11 remains fixed.

[0086] The contact support and the film 11 are only in contact and not fixedly connected. Therefore, during the unfolding of the film 11, a certain degree of relative movement occurs between the contact support and the film 11, thereby achieving the desired unfolding. Furthermore, the contact support provides circumferential support to the film 11 without providing radial or circumferential relative movement constraints, allowing the film 11 to undergo radial or circumferential relative movement relative to the contact support, thus changing the location of contact between the film 11 and the contact support or bracket during unfolding.

[0087] like Figure 5 , Figure 6As shown, the membrane 11 includes a cylindrical section 110 and a proximal conical section 111 disposed at the proximal end of the cylindrical section 110. The axial length of the cylindrical section 110 is greater than the length of the proximal conical section 111. The blood inlet 13 extends from the proximal conical section 111 to the cylindrical section 110, and the length of the cylindrical section 110 of the membrane 11 is greater than the length of the proximal conical section 111.

[0088] A connecting ring 16 is provided at the proximal end of the proximal tapered segment 111. The connecting ring 16 is fixedly connected to the outer wall of the conduit 2, thereby achieving a fixed connection to the distal end 18 of the membrane 11. The connecting ring 16 can be fixedly connected to the conduit 2 by adhesive bonding, heat fusion, or compression fitting. The connection position between the membrane 11 and the conduit 2, or the position of the connecting ring 16, is located on the proximal side of the proximal bearing chamber 7.

[0089] Of these, some blood outlets 21 are located in the proximal conical section 111, and another portion of blood outlets 20 are located in the cylindrical section 110. Multiple blood outlets 14 are arranged circumferentially. The presence of some blood outlets 20 in the cylindrical section 110 allows the output blood to flow centrifugally at that location, thus stabilizing the position of the pump body 1 and ensuring stable blood flow from the multiple blood outlets 14. The presence of some blood outlets 21 in the proximal conical section 111 allows the output blood to flow approximately axially, which, together with the blood outlets 14 in the cylindrical section 110, ensures the flow rate of the blood outlets 14 and prevents flow direction loss.

[0090] To maintain the structural strength of the front end of the membrane 11 and to maintain the stability of the shape structure, the circumferential width of the blood inlet 13, at least a portion of its axial length, gradually decreases as it extends from its distal end to its proximal end.

[0091] In this embodiment, as Figure 5 , Figure 6 As shown, the circumferential width of the blood outlet 21 located in the proximal conical segment 111 gradually decreases as it extends from the distal end to the proximal end, while the circumferential width of the other blood outlet 20 located in the cylindrical segment 110 gradually increases as it extends from the distal end to the proximal end.

[0092] In one embodiment, such as Figure 7 As shown, the circumferential width of the blood outlet 14 gradually decreases along the direction extending from the distal end to the proximal end.

[0093] The portion of blood outlet 14 located in the proximal conical section 111 is designated as the rear blood outlet portion 21, and the other portion of blood outlet 14 located in the cylindrical section 110 is designated as the front blood outlet portion 20. The length of the portion of blood outlet 14 in the proximal conical section 111 is greater than the length of its portion in the cylindrical section 110. That is, the length of the rear blood outlet portion 21 is greater than the length of the front blood outlet portion 20.

[0094] The circumferential width of at least a portion (axial) of the front blood outlet portion 20 is greater than or equal to the maximum circumferential width of the rear blood outlet portion 21. In the rear blood outlet portion 21, at any two axial locations of the blood outlet 14, the circumferential width of the downstream location is less than or equal to the circumferential width of the upstream location. The circumferential width of the proximal end of the blood outlet 14 is less than the circumferential width of its distal end.

[0095] In this embodiment, the support member 12 or a single bracket is an integrally formed structure, while the support member 12 and the covering film 11 are separate structures. At least a portion of the support member 12 is located inside the covering film 11 and contacts the inner wall of the supporting covering film 11.

[0096] In the unloaded radially expanded state of the pump casing 10, the support member 12 is radially constrained by the membrane 11 and does not fully expand. The support member 12 is made of shape memory alloy. After losing the constraint of the sheath, the support member 12 recovers its shape and expands the membrane 11 until it is constrained by the membrane 11 and can no longer expand. At this time, the support member 12 provides radially outward support force to the membrane 11. The membrane 11 resists the deformation of the support member 12 with its own toughness, does not produce tensile deformation, and maintains the stability of its shape.

[0097] It should be noted that the support member 12 of the present invention is not limited to a single support in the membrane 11, but may also include multiple supports distributed at different axial positions to support different parts of the membrane 11. For example, there may be a support for the proximal end 17 of the membrane 11 to stably support the blood outlet 14, maintain the stability of the shape of the blood outlet 14, and reduce the impact on blood flow.

[0098] In this embodiment, the support member 12 is a bracket with a mesh structure. The design of the multiple mesh holes, especially the diamond-shaped mesh holes, on the foldable bracket facilitates the folding and unfolding of the support member 12. The impeller 5 is housed within the support member 12 and located within the membrane 11.

[0099] The support member 12 is supported at the distal end 18 of the membrane 11, with part of the support member 12 located outside the distal end 18 of the membrane 11 and the other part located inside the membrane 11. The impeller 5 is fixedly mounted on the impeller shaft 6, which is rotatably fitted inside the support member 12, and the distal end of the impeller shaft 6 is rotatably supported in the distal bearing chamber 15. The distal end of the support member 12 is fixedly connected to the distal bearing chamber 15.

[0100] The support member 12 has a spindle-shaped structure, providing a support space to accommodate the impeller 5. The proximal end of the support member 12 is connected to the distal end of the conduit 2. The proximal end of the support member 12 of the pump body 1 is fixedly connected to the distal end of the conduit 2. The proximal end 17 of the membrane 11 is fixedly sleeved on the outer wall of the conduit 2 on one side of the proximal end of the support member 12.

[0101] The distal end of the duct 2 has a proximal bearing chamber 7, through which the proximal ring 125 of the support member 12 is connected. The proximal bearing chamber 7 contains a proximal bearing for rotating support of the drive shaft. The distal bearing chamber 15 is located at the distal end of the drive shaft and rotates to support the distal end of the drive shaft via the distal bearing. The distal end of the support member 12 is fixedly connected to the distal bearing chamber 15, maintaining the distance between the proximal bearing chamber 7 and the distal bearing chamber 15, thereby providing stable rotational support for the impeller shaft 6.

[0102] A non-invasive support member 8 is also fixedly connected to the distal end of the distal bearing chamber 15. The non-invasive support member 8 is a flexible tubular structure, characterized by a flexible protrusion (pigtail or tip member) with an arc-shaped or coiled end. This flexible end is supported on the ventricular wall in a non-invasive or non-damaging manner, separating the suction port (blood inlet 13) of the pump body 1 from the ventricular wall. This prevents the suction port of the pump body 1 from adhering to the ventricular wall due to the reaction force of the fluid (blood) during operation, thus ensuring the effective suction area of ​​the pump body 1.

[0103] Pump body 1 is a collapsible pump body. To reduce subject discomfort and facilitate intervention, pump body 1 is desired to be small in size. However, to provide stronger assistive functions for the subject, pump body 1 is desired to have a high flow rate, which generally requires a larger pump body 1.

[0104] By designing a retractable pump body 1, the pump body 1 has a small retractable size and a large unfolded size, so as to meet the needs of reducing the patient's pain and making the intervention easy during the intervention / delivery process, as well as providing a large flow rate.

[0105] As described above, the design of the multi-mesh structure, especially the diamond-shaped mesh, of the support member 12 can achieve better folding and unfolding by taking advantage of the memory properties of the nickel-titanium alloy.

[0106] The blade 50 is made of a flexible material that stores energy when folded. When the external constraints are removed, the stored energy of the blade 50 is released, causing the blade 50 to unfold.

[0107] The pump body 1 is folded down by external constraints, and unfolds itself after the constraints are removed. In this embodiment, the "folded state" refers to the state in which the pump body 1 is radially constrained, that is, the pump body 1 is radially compressed and folded to its minimum radial dimension under external pressure. The "unfolded state" refers to the state in which the pump body 1 is not radially constrained, that is, the bracket and impeller 5 are radially unfolded to their maximum radial dimension.

[0108] The aforementioned external constraints are applied by a folded sheath (not shown) that slides around the outside of the conduit 2. When the folded sheath moves forward outside the conduit 2, the pump body 1 can be completely housed within it, achieving forced folding of the pump body 1. When the folded sheath moves backward, the radial constraint on the pump body 1 disappears, and the pump body 1 unfolds on its own.

[0109] As described above, the folding of the pump body 1 is achieved by the radial constraint force applied by the folded sheath. Since the impeller 5 contained in the pump body 1 is housed within the pump casing 10, the folding process of the pump body 1 is essentially as follows: the folded sheath applies a radial constraint force to the pump casing 10, and when the pump casing 10 is radially compressed, it applies a radial constraint force to the impeller 5.

[0110] In other words, the pump casing 10 is folded directly by the folding sheath, while the impeller 5 is folded directly by the pump casing 10. As mentioned above, the impeller 5 is elastic. Therefore, although it is in a folded state, the energy stored in the folding of the impeller 5 makes it always tend to expand radially, thus the impeller 5 will contact the inner wall of the pump casing 10 and exert a reaction force on the pump casing 10.

[0111] After the constraints of the folded sheath are removed, the pump casing 10, under its own memory characteristics, supports the unfolding of the elastic diaphragm 11, and the impeller 5 unfolds itself under the released energy storage. In the unfolded state, the outer diameter of the impeller 5 is smaller than the inner diameter of the pump casing 10.

[0112] In this way, a gap is maintained between the radially outer end of the impeller 5 (that is, the tip of the blade 50) and the inner wall of the pump casing 10 (specifically, the inner wall of the support), and this gap is called the pump clearance. The existence of the pump clearance allows the impeller 5 to rotate without obstruction and without hitting the wall.

[0113] Furthermore, from a fluid dynamics perspective, it is desirable for the pump clearance to be small and maintained. In this embodiment, the outer diameter of the impeller 5 is slightly smaller than the inner diameter of the support member 12, so that the pump clearance is as small as possible while ensuring that the impeller 5 rotates without hitting the wall. The main means of maintaining the pump clearance is through the support strength provided by the support member 12 and the tensile deformation resistance of the membrane 11. This support strength and the toughness of the membrane 11 can resist the back pressure of the fluid (blood) without excessive deformation, thereby maintaining the shape stability of the pump casing 10, and thus the pump clearance is also stably maintained.

[0114] The folding and unfolding process of pump body 1 is as follows:

[0115] During the process of inserting pump body 1 into the left ventricle, pump body 1 is in a radially constrained state (folded state) due to the externally applied radial constraint force. After being inserted into the left ventricle and the radial constraint force is removed, the support member 12 expands autonomously by utilizing its own memory characteristics and the blades 50 of the impeller 5 by releasing stored energy, so pump body 1 automatically presents its unconstrained shape (expanded state).

[0116] Conversely, when the pump body 1 needs to be withdrawn from the subject's body after completing its work, the pump body 1 is folded up using a folding sheath. Once the pump body 1 is completely withdrawn from the subject's body, the constraint of the folding sheath on the pump body 1 is removed, allowing the pump body 1 to return to its natural state of minimum stress, which is the unfolded state.

[0117] The above descriptions are merely a few embodiments of the present invention. Those skilled in the art can make various modifications or variations to the embodiments of the present invention based on the content disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A pump body for an interventional catheter pump, characterized in that, The pump body can be delivered to a desired location on the heart to pump blood; the pump body includes: A pump housing having a blood inlet and a blood outlet, and an impeller housed within the pump housing for powering the flow of blood; the pump housing includes at least a membrane defining a blood flow channel and a support member for supporting the deployment of the membrane; The pump body includes a radially folded state and a radially extended state, and the pump body can be operatively switched between the radially folded state and the radially extended state; The distal end of the membrane has a distal opening, which, when unfolded by the support member, forms the blood inlet together with the support member.

2. The pump body according to claim 1, characterized in that, The distal end of the coating is also provided with a connecting strip, and the distal end of the connecting strip is fixedly connected to the distal bearing chamber; when the coating is in the radially expanded state, the connecting strip is in a roughly taut and stretched state.

3. The pump body according to claim 1, characterized in that, The radial unfolding state includes the natural unfolding state corresponding to when the impeller is not rotating; In its naturally unfolded state, the pump casing has a contact support portion that contacts the membrane, and the contact support portion and the membrane are in contact support.

4. The pump body according to claim 3, characterized in that, In the operating state, at least a portion of the contact support portion of the pump housing is separated from the membrane.

5. The pump body according to claim 3, characterized in that, There is no fixed connection between the contact support and the film.

6. The pump body according to claim 3, characterized in that, The distal inner wall of the coating is bonded to the outer wall of the support member.

7. The pump body according to claim 3, characterized in that, The support member includes a conical support proximal end, a conical support distal end, and a cylindrical support segment located between the conical support proximal end and the conical support distal end; The cylindrical bracket segment, at least a portion of its axial length, constitutes the contact support portion.

8. The pump body according to claim 7, characterized in that, The membrane is fitted over the cylindrical support section, and the membrane is supported by the cylindrical support section to form a stable cylindrical pump casing.

9. The pump body according to claim 7, characterized in that, The distal end face of the coating does not extend beyond the cylindrical support segment.

10. The pump body according to claim 1, characterized in that, The coating includes a cylindrical section and a proximal conical section disposed at the proximal end of the cylindrical section; The proximal end of the proximal conical segment is provided with a connecting ring sleeve, which is fixedly connected to the outer wall of the catheter of the interventional catheter pump.

11. The pump body according to claim 1, characterized in that, The support member is supported at the distal end of the membrane, with a portion of the support member located outside the distal end of the membrane and another portion located inside the membrane.

12. The pump body according to any one of claims 1 to 11, characterized in that, The membrane is configured to not undergo tensile deformation when the pump housing is in the radially expanded state, compared to the unstressed state. The radial unfolding state includes the natural unfolding state when the impeller is not rotating, and the working state when the impeller is rotating; The membrane is configured such that the critical stress causing it to tensile deformation is greater than or equal to the force exerted on it by the support member when the pump housing is in the naturally unfolded state. The critical stress at which the membrane undergoes tensile deformation is greater than or equal to the force exerted on the membrane by the blood back pressure caused by the rotation of the impeller when the pump body is in maximum operating condition. When the pump body is in the operating state, the blood back pressure applied to the membrane caused by the rotation of the impeller causes the wrinkles of the membrane to be at least partially flattened, and the flattening of the wrinkles causes the diameter of the membrane to increase.

13. The pump body according to any one of claims 1 to 11, characterized in that, The pump body has an intervention configuration and a working configuration; With the pump body corresponding to the aforementioned intervention configuration, the pump casing and the impeller are in a radially constricted state; In the working configuration corresponding to the pump body, the pump casing and the impeller are in a radially extended state.

14. The pump body according to any one of claims 1 to 11, characterized in that, The impeller is housed within the support member and located within the membrane.

15. An interventional catheter pump, wherein, include: catheter; The drive shaft passes through the conduit; The power assembly is connected to the proximal end of the drive shaft; The pump body as described in any one of claims 1-14, wherein the impeller of the pump body is connected to the distal end of the drive shaft.

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