Interventional catheter pump and pump body thereof

Abstract

Disclosed are an interventional catheter pump capable of stably maintaining a pump gap and a pump body thereof. The pump body comprises: a pump shell having a blood inlet and a blood outlet; an impeller accommodated in the pump shell and used for providing power for blood flow; and a covering film provided in the pump shell and used for defining a blood flow channel. The pump body comprises a radially folded state and a radially unfolded state, and the pump body is operable to be switched between the radially folded state and the radially unfolded state. The covering film is configured to not be stretched in the radially unfolded state of the pump shell compared with an unstressed state.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of medical devices, in particular to a device for cardiac assist use, more particularly to an interventional catheter pump and a pump body thereof. BACKGROUND

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

[0003] In order to ensure stable contraction and expansion, the existing catheter pump can be inserted into the blood vessel of the patient and can be expanded after being inserted. During the compression and expansion, the rotor (for example, the impeller) and the shell will be deformed accordingly, and at this time, the problem is that the pump gap, that is, the interval gap between the radially outer end of the impeller and the inner wall of the shell, needs to be kept in a minimum state and remain stable in order to optimize the efficiency of the pump. SUMMARY

[0004] In view of the above deficiencies, an object of the present application is to provide an interventional catheter pump and a power transmission assembly thereof capable of stably maintaining the pump gap.

[0005] To achieve the above object, the present application adopts the following technical solutions:

[0006] An interventional catheter pump body capable of pumping blood when delivered to a desired location of a heart; comprising: a pump housing having a blood inlet and a blood outlet, an impeller housed within the pump housing and configured to provide a motive force for blood flow; the pump housing comprises at least a membrane defining a blood flow passage. The pump body comprises a radially collapsed state and a radially expanded state, and is operable to switch between the radially collapsed state and the radially expanded state. The membrane is configured to not stretch when the pump housing is in the radially expanded state compared to an unstressed state.

[0007] An interventional catheter pump body capable of pumping blood when delivered to a desired location of a heart; comprising: a pump housing having a blood inlet and a blood outlet, an impeller housed within the pump housing and configured to provide a motive force for blood flow; the pump housing comprises at least a membrane defining a blood flow passage. The pump body comprises a radially collapsed state suitable for delivery in a subject's vasculature, a natural expanded state corresponding to when the impeller is not rotating, and a working state corresponding to when the impeller is rotating. During the process of switching the pump body from the natural expanded state to the working state, the blood back pressure exerted on the membrane by the rotation of the impeller causes the wrinkles of the membrane to be at least partially flattened.

[0008] Preferably, the flattening of the wrinkles causes the diameter of the membrane to increase.

[0009] Preferably, the flattening of the folds is such that the increase in diameter of the covering is not more than 3%.

[0010] Preferably, during the passage from the natural deployed state to the working state, the covering undergoes at least a sub-process in which the diameter does not increase.

[0011] Preferably, the covering is configured so as not to undergo tensile deformation when the pump housing is in the natural deployed state or in the working state, compared to the unstressed state.

[0012] Preferably, the pump housing further comprises a support member for supporting the deployed covering; the radially deployed state comprises a natural deployed state corresponding to the impeller not rotating; the covering is configured so that the critical point stress at which it undergoes tensile deformation is greater than or equal to the force exerted by the support member on it when the pump housing is in the natural deployed state.

[0013] Preferably, the radially deployed state further comprises a working state corresponding to the impeller rotating; the critical point stress at which the covering undergoes tensile deformation is greater than or equal to the force exerted on it by the blood back pressure due to the rotation of the impeller when the pump body is in the maximum operating condition.

[0014] Preferably, the material strength of the covering itself is sufficient to resist the outward expansion force of the support member, and in turn the circumferential tensile deformation of the covering when the pump housing is switched from the radially collapsed state to the natural deployed state is 0.

[0015] Preferably, the material strength of the covering itself is sufficient to resist the force exerted on it by the blood back pressure due to the rotation of the impeller, and in turn the circumferential tensile deformation of the covering when the pump housing is switched from the natural deployed state to the working state is 0.

[0016] Preferably, the diameter of the covering when the pump body is in the working state is greater than the diameter of the covering when the pump body is in the natural deployed state.

[0017] Preferably, the pump body comprises a working state corresponding to the impeller rotating; the blood back pressure exerted on the covering due to the rotation of the impeller when the pump body is in the working state causes the folds of the covering to be at least partially flattened.

[0018] A pump body for an interventional catheter pump, capable of being delivered to a desired location in the heart to pump blood; comprising: a pump housing having a blood inlet and a blood outlet, an impeller housed within the pump housing and configured to provide power for the flow of blood; the pump housing comprising at least a covering defining a blood flow passage. The pump body comprises a radially collapsed state suitable for delivery in the vasculature of a subject, a natural deployed state corresponding to the impeller not rotating, and a working state corresponding to the impeller rotating. The diameter of the covering when the pump body is in the working state is greater than the diameter of the covering when the pump body is in the natural deployed state.

[0019] Preferably, the pump housing further comprises a support member for supporting the expanded covering; in the natural expanded state, the support member is radially constrained by the covering and is not fully expanded.

[0020] Preferably, the pump housing further comprises a support member for supporting the expanded covering; in the natural expanded state, the support member has a contact support portion in contact with the covering. In the working state, at least a portion of the contact support portion is spaced apart from the covering.

[0021] Preferably, the covering comprises a cylindrical segment, a proximal conical segment disposed at the proximal end of the cylindrical segment. The blood inlet extends from the proximal conical segment to the cylindrical segment, and the blood outlet is partially located in the proximal conical segment and partially located in the cylindrical segment. The blood inlet has a gradually decreasing circumferential width from the distal end to the proximal end of at least a portion of the axial length. Alternatively, the length of the portion of the blood outlet in the proximal conical segment is greater than the length of the portion of the blood outlet in the cylindrical segment.

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

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

[0024] The catheter pump and the pump body provided by the embodiments of the present application have the advantages that the covering does not produce tensile deformation in the radially expanded state, and the covering has strong deformation resistance. Furthermore, the covering can stably constrain and maintain the shape of the support member in the radially expanded state, keep the pump gap, and keep the pump body having a better pump efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a structural schematic diagram of an interventional catheter pump provided by an embodiment of the present application;

[0026] Figure 2 is Figure 1 an enlarged view of part A of

[0027] Figure 3 is Figure 2 a perspective view of

[0028] Figure 4 is Figure 3 a partial cross-sectional view of

[0029] Figure 5 is Figure 1 a perspective view of the covering of

[0030] Figure 6 is Figure 5 a front view of

[0031] Figure 7 is a schematic view of a pump body of an interventional catheter pump according to another embodiment of the present application;

[0032] Figure 8 is a graph of the diameter change of six different pump bodies of the present application under fluid back pressure.

[0033] BRIEF DESCRIPTION OF DRAWINGS 1. Pump body; 2. Catheter; 3. Power assembly; 4. Coupling body; 5. Impeller; 6. Impeller shaft; 7. Proximal bearing chamber; 8. Flexible support; 10. Pump housing; 11. Membrane; 12. Support member; 13. Blood inlet; 14. Blood outlet; 15. Distal bearing chamber; 16. Connection collar; 17. Membrane proximal end; 18. Membrane distal end; 19. Connection strip; 20. Front blood outlet portion; 21. Rear blood outlet portion; 50. Blades; 51. Hub; 121. Conical support proximal end; 123. Conical support distal end; 122. Cylindrical support section; 125. Collar; 110. Cylinder section; 111. Proximal conical section. DETAILED DESCRIPTION

[0034] In order to make the technical solutions in the present application better understood, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work should belong to the scope of protection of the present application.

[0035] It should be noted that when an element is referred to as being "on" another element, it can be directly on the other element or an intervening element can also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or an intervening element can also be present. The terms "vertical", "horizontal", "left", "right", and similar expressions used herein are only for the purpose of illustration and are not intended to be the only implementation.

[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 application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0037] The terms "proximal", "distal" and "anterior", "posterior" are relative to the clinician who manipulates the interventional catheter pump. The terms "proximal", "posterior" refer to the parts relatively close to the clinician, and the terms "distal", "anterior" refer to the parts relatively far from the clinician. For example, the extracorporeal part is at the proximal end and the posterior end, and the intracorporeal interventional part is at the distal end and the anterior end.

[0038] Please refer to Figures 1 to 6 The interventional catheter pump of the embodiment of the present application comprises a pump body 1, a catheter 2, and a power assembly 3. The power assembly 3 is arranged at the proximal end of the catheter 2, is connected to the catheter 2 through a coupling body 4, and is connected to the pump body 1 through a flexible shaft arranged in the catheter 2.

[0039] The pump body 1 can be delivered to a desired position of the heart to pump blood. The power source of the pump body 1 can be an external motor or an internal motor, and the present application does not make a special limitation. In the embodiment in which the power source is external, the pump body 1 can be connected to an external motor through the catheter 2, and the catheter 2 accommodates the flexible shaft to transmit power to the impeller 5 of the pump body 1.

[0040] In the embodiment in which the power source is internal, the internal motor can be a hydraulic motor or an electric motor (for example, a motor). The power assembly 3 can be sent into the body by relying on the catheter 2 and is kept in a position close to the pump body 1, so as to reduce the length of the connecting shaft between the two and thereby reduce the friction heat and other problems caused by the rotation of the long shaft.

[0041] The pump body 1 comprises a pump shell 10 having a blood inlet 13 and a blood outlet 14, and an impeller 5 accommodated in the pump shell 10. The impeller 5 is used to provide power for the flow of blood, and the pump shell 10 at least comprises a covering film 11 defining a blood flow channel.

[0042] The pump body 1 comprises a radially collapsed state and a radially expanded state. The pump shell 10 is operatively switchable between the radially collapsed state and the radially expanded state. Compared with the unstressed state, the covering film 11 does not produce tensile deformation when the pump shell is in the radially expanded state.

[0043] The pump shell 10 further comprises a support member 12 for supporting the expanded covering film 11. The support member 12 can be integrally arranged in the covering film 11 or even arranged outside the covering film 11 to support the covering film 11.

[0044] In the radially expanded state, the support member 12 contacts the inner wall of the covering film 11 to expand the covering film 11 radially. Compared with the covering film 11 in the radially expanded state of the pump shell 10 in the unstressed state, the covering film 11 does not produce tensile deformation in the unstressed state.

[0045] The radially expanded state of the pump shell 10 in the unstressed state is the natural expanded state when the impeller 5 is not rotating.

[0046] The radially expanded state includes a natural expanded state corresponding to the impeller 5 not rotating. The critical point stress at which the covering 11 is deformed by stretching is greater than or equal to the force exerted by the support member 12 on the pump housing in the natural expanded state. Thus, when only the support member 12 exerts a radial support expansion force on the covering 11, the critical force at which the covering 11 is deformed by stretching is not reached, and the covering 11 does not deform by stretching in the natural expanded state supported by the support member 12.

[0047] The radially expanded state also includes an operating state corresponding to the impeller 5 rotating. To ensure the toughness of the covering 11 and provide a more stable pump gap and pump efficiency, the critical point stress at which the covering 11 is deformed by stretching is greater than or equal to the force exerted by the blood back pressure on the covering 11 due to the rotation of the impeller 5 when the pump body 1 is in the maximum working condition.

[0048] The maximum working condition of the pump body 1 corresponds to the maximum rotational speed of the impeller 5 at rated power. At this time, the pump flow corresponds to the maximum value, and the blood back pressure is also at the maximum value. In this embodiment, the maximum value of the blood back pressure still does not exceed the critical point stress at which the covering 11 is deformed by stretching, and thus the covering 11 will not deform by stretching in the operating state of the impeller rotating, to avoid changes in the pump gap and stabilize the pump efficiency.

[0049] It should be clear that the deformation by stretching of the covering 11 in the present application refers to the deformation of the length of the covering 11 in the circumferential direction. When subjected to a radial force, it manifests as an increase in the circumferential length (circumference). However, in the case of the covering 11 having wrinkles, the flattening of the wrinkles by the expansion of the support member 12 does not constitute stretching of the covering 11.

[0050] The wrinkles of the covering 11 are mostly caused by folding. Due to the radial constraint of the folding sheath, the covering 11 is forced to compress and fold, thereby causing the wrinkles to form. Of course, this does not rule out other factors causing the covering 11 to wrinkle. For example, it can be formed during manufacturing, or it can be deformed by itself when placed, or it can be caused during testing, etc. The wrinkles can be in the form of creases, (fine) wrinkles, etc.

[0051] The pump body 1 has an interventional configuration and an operating configuration. In the interventional configuration of the pump body 1, the pump housing 10 and the impeller 5 are in a radially folded state, so that the pump body 1 has a first outer diameter size and is inserted into and / or transported in the vasculature of the subject. In the operating configuration of the pump body 1, the pump housing 10 and the impeller 5 are in a radially expanded state, so that the pump body 1 has a second outer diameter size greater than the first outer diameter size and pumps blood at the desired location (e.g., the left ventricle).

[0052] As Figure 4As 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 to drive blood flow by rotation.

[0053] In the corresponding intervention configuration of the pump body 1, the blades 50 are wrapped on the outer wall of the hub 51 and at least partially in contact with the inner wall of the pump shell 10. In the corresponding working configuration of the pump body 1, the blades 50 extend radially outward from the hub 51 and are spaced from the inner wall of the pump shell 10, avoiding the influence of the pump shell 10 on the rotation of the blades 50, and avoiding damage to the pump shell 10 by the rotation of the blades 50.

[0054] In use, the pump body 1 and part of the catheter 2 (specifically the front end part of the catheter 2) are sent into and maintained in the body of a subject, and the size of the pump body 1 and part of the catheter 2 needs to be as small as possible. Therefore, the axial projection area of the pump body 1 and part of the catheter 2 is smaller than the axial projection area of other parts of the power assembly 3 (such as the motor) including the pump body 1.

[0055] Thus, the smaller size of the pump body 1 and part of the catheter 2 can reduce the pain of the subject during the process of being sent into and maintained in the body of the subject, and reduce complications caused by excessive size of the intervention. Other parts of the power assembly 3 can have relatively large sizes to meet the needs of structural design.

[0056] The catheter pump can displace heart blood, pump blood from the left ventricle into the aorta, provide support for blood circulation, reduce the workload of the heart of the subject, or provide additional continuous pump blood power support when the heart pump body 1 is insufficient. Of course, the catheter pump can also be placed at a desired position in the human body, such as a blood vessel or other organs, for blood or body fluid pumping, relying on interventional surgery.

[0057] In the present embodiment, the material strength of the covering membrane 11 itself is sufficient to resist the outward expansion force of the supporting member, and the circumferential tensile deformation amount of the covering membrane 11 is 0 when the pump shell 10 is switched from the radially collapsed state to the naturally expanded state, and no circumferential tensile deformation occurs.

[0058] Further, the material strength of the covering membrane 11 itself is sufficient to resist the force exerted by the blood back pressure due to the rotation of the impeller 5, and the circumferential tensile deformation amount of the covering membrane 11 is 0 when the pump shell is switched from the naturally expanded state to the working state.

[0059] The material of the cover film 11 is TPU (thermoplastic polyurethane elastomer rubber) or PEBAX material or PTFE (polytetrafluoroethylene). Preferably, the cover film 11 is made of a block polyether amide resin material such as PEBAX. The cover film 11 has no loss of mechanical properties under repeated deformation and is fatigue resistant, with good resilience and elastic recovery properties and precise dimensional stability. Furthermore, it does not produce tensile deformation under the support of the support member 12, stably maintaining the pump gap.

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

[0061] It can be understood that the inner diameter or inner cross-sectional area of the cover film 11 does not change in the unstressed state compared to the naturally expanded state. The cover film 11 in the unstressed state of the pump housing 10 is a cylindrical structure without being supported by the support member 12. It can also be understood that the cover film 11 does not produce tensile deformation in the naturally expanded state compared to the state of being supported from the inside to the outside by the support member 12, and the amount of tensile deformation is 0.

[0062] The unstressed condition (naturally expanded state) in the radial expansion state is compared to the condition of the impeller 5 rotating to drive the fluid (working state). In the case of the impeller 5 rotating to drive the blood flow, the blood will also produce a certain radial expansion force (fluid back pressure) on the cover film 11.

[0063] The cover film 11 does not produce tensile deformation in the radial expansion state of the pump housing 10, i.e. only by the support member 12 applying an expansion force to the cover film 11, and has good anti-deformation ability. Furthermore, it better maintains the shape during blood pumping, maintains the pump gap, and maintains the pump efficiency.

[0064] Further, the cover film 11 does not produce tensile deformation in the radial expansion state, and the cover film 11 has strong anti-deformation ability. In this way, the shape of the support member 12 can be stably constrained and maintained in the radial expansion state, the pump gap is maintained, and the pump body 1 is in a better pump efficiency.

[0065] Based on the above description, the pump body 1 includes a radial folding state suitable for delivery in the vasculature of a subject, a naturally expanded state corresponding to the non-rotation of the impeller 5, and a working state corresponding to the rotation of the impeller 5. During the switching of the pump body 1 from the naturally expanded state to the working state, the blood back pressure exerted on the cover film 11 by the rotation of the impeller 5 causes the wrinkles of the cover film 11 to be at least partially flattened.

[0066] The flattening of the folds causes an increase in the diameter of the covering 11, the increase in the diameter of the covering 11 caused by the flattening of the folds being less than 3%, further less than 2%, and even less than 1%.

[0067] The increase in the diameter mentioned above is the variation in the diameter of the covering 11 between the natural unfolded state and the working state of the pump casing 10, and depends on the number and amplitude of the folds of the covering 11, and further on the flexibility of the material of the covering 11.

[0068] In particular, the flexibility of the material of the covering 11 determines to a large extent the number and amplitude of the folds. That is, the worse the flexibility of the material of the covering 11, the more folds the covering 11 can have and the greater the amplitude of the folds, and the closer the increase in the diameter of the covering 11 caused by the flattening of the folds is to 3%. Conversely, the better the flexibility of the material of the covering 11, the fewer folds the covering 11 has and the smaller the amplitude of the folds, and the further the increase in the diameter of the covering 11 caused by the flattening of the folds is from 3%.

[0069] Thus, in certain scenarios that cannot be explicitly excluded, the contribution of the flattening of the folds to the increase in the diameter of the covering 11 can be close to 0 in the case where the material of the covering 11 chosen has such a particularly soft character that it has very few folds.

[0070] The covering 11 is a one-piece structure, the distal end 19 of the covering 11 has a distal end opening which is circular and is unfolded by the support member 12, and forms with the support member 12 the blood inlet 13 of the pump casing 10. The distal end 19 of the covering 11 is also provided with a connecting strip 19, the distal end of which is fixed to the distal end bearing chamber 15.

[0071] In the radially unfolded state of the covering 11, the connecting strip 19 is in a substantially straightened and stretched state, and the proximal and distal ends of the covering 11 are fixed by the connecting strip 19 and the connecting ring 16 of the distal end 18 of the covering 11, and thus the covering 11 is in an overall flat state in the axial direction, providing a continuous and stable rotation pump blood space for the rotation of the impeller 5.

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

[0073] In the natural unfolded state of the pump casing 10, the support member 12 has a contact support portion in contact with the covering 11. In particular, the support member 12 includes a conical support proximal end 121, a conical support distal end 123, and a cylindrical support section 122 between the conical support proximal end 121 and the conical support distal end 123. At least part of the axial length of the cylindrical support section 122 forms the contact support portion.

[0074] The cover film 11 is sleeved on the outer side of the cylindrical support section 122 and is supported by the cylindrical support section 122 to form a stable cylindrical pump housing 10. The distal end 19 (end surface) of the cover film 11 does not exceed the cylindrical support section 122.

[0075] The radial expansion state of the pump housing 10 forms a working configuration. In the working configuration, there is a state in which the impeller 5 rotates to drive blood flow (working state) and a state in which the impeller 5 is stationary (natural expansion state). Due to the different states of the blood (stationary and flowing), different forces are generated on the cover film 11. Furthermore, in the state in which the impeller 5 rotates to drive blood flow, not only is there a supporting force of the support member 12 on the cover film 11, but there is also a radial pushing (fluid back pressure) of the cover film 11 by the blood driven by the impeller 5.

[0076] Therefore, compared with the cover film 11 in the non-working state (natural expansion state), in the working state of the impeller 5 at a high rotational speed (thousands of revolutions or even tens of thousands of revolutions per minute), the cover film 11 is stretched in the circumferential direction due to the unfolding of the folds, and the stretching of the cover film 11 itself does not occur in the circumferential direction.

[0077] The diameter of the cover film 11 in the working state of the pump body 1 is greater than the diameter of the cover film 11 in the natural expansion state of the pump body. In the natural expansion state of the pump body 1, the diameter of the cover film 11 is a first diameter. In the working state of the pump body, the diameter of the cover film 11 is a second diameter. The second diameter is greater than the first diameter.

[0078] The diameter is the diameter of the cover film 11 surrounding the internal cavity. In the working state, due to the existence of the fluid back pressure, at least part of the folds of the cover film 11 are unfolded, so that the cross-sectional shape of the surrounding internal cavity tends to be circular, the inner wall of the cover film 11 tends to be smooth, and the diameter of the cover film 11 (the diameter of the surrounding cavity) increases.

[0079] Specifically, in the working state of the pump housing 10, the blood back pressure exerted on the cover film 11 by the rotation of the impeller 5 causes the folds of the cover film 11 to be at least partially unfolded. In the process of switching the pump body 1 from the natural expansion state to the working state, the blood back pressure exerted on the cover film 11 by the rotation of the impeller 5 causes the folds of the cover film 11 to be at least partially unfolded, and the unfolding of the folds causes the diameter of the cover film 11 to increase at a rate of not more than 3%.

[0080] The rate of increase in the diameter is not more than 3%. Figure 8The diameter variation of the 6 groups of the film 11 (1#-A to 3#-C represent different film names) in the different back pressure can be seen. In each graph, two pressure end point values and the film 11 diameter at an approximate intermediate pressure are shown. As can be seen from each graph, as the back pressure increases, the circumferential direction of the film 11 is elongated 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 housing 10 from the natural unfolded state to the working state, the film 11 at least has a sub-process in which the diameter does not increase. During the test, as the back pressure increases, the diameter of the film 11 sometimes remains unchanged or even decreases within a certain pressure range.

[0082] The reason for the above-mentioned process of not increasing the diameter is that due to the existence of the folds, the film 11 in the natural unfolded state presents a cross-sectional shape that is approximately circular but not strictly circular. The folds include radial inward recesses, and there can also be radial outward protrusions. If the selected diameter measurement point is the two protruding points, the initially measured diameter is larger, and after the folds are flattened, the protrusions are flattened, thereby causing the diameter to decrease although the back pressure increases.

[0083] Of course, this further or indirectly proves that the circumferential elongation of the film 11 in the present application is due to the flattening of the folds rather than the tensile deformation. Because tensile deformation will cause the diameter to continuously increase, and will not appear unchanged and decreased.

[0084] In one embodiment, at least a part of the contact support part (cylindrical support section 122) is separated from the film 11 when the impeller 5 is rotating to drive the blood flow. Under the action of the fluid back pressure, part of the folds of the film 11 are further flattened, and the inner diameter is increased to be separated from the contact support part. Under the action of the toughness of the film 11 itself, the tensile deformation is limited, and the further flattening of the folds causes the circumferential elongation of the film 11, but the elongation rate change is less than 3%, the circumferential elongation change is small, and the separation gap between the impeller 5 and the film 11 is maintained in the working state, and the pump efficiency is continuously and stably maintained.

[0085] During the transition of the pump housing 10 from the radially folded state to the radially unfolded state, the contact support part and the film 11 are allowed to move relative to each other, and the part of the film 11 that contacts the contact support part such as the cylindrical support section 122 is allowed to change. The relative position between the support member 12 and the film 11 does not change.

[0086] The contact support part is only in contact with the covering film 11 without fixed connection, and then a certain degree of relative movement is formed between the contact support part and the covering film 11 during the unfolding of the covering film 11, so as to realize the desired unfolding of each other. Moreover, the contact support part provides a circumferential support force to the covering film 11 without providing a radial and circumferential relative motion constraint, allowing the covering film 11 to generate a radial or circumferential relative motion with respect to the contact support part, so that the position of the covering film 11 in contact with the contact support part or the stent changes during the unfolding process.

[0087] As shown in Figure 5 , Figure 6 , the covering film 11 includes a cylindrical segment 110 and a proximal conical segment 111 arranged at the proximal end of the cylindrical segment 110. The axial length of the cylindrical segment 110 is greater than the length of the proximal conical segment 111. The blood inlet 13 extends from the proximal conical segment 111 to the cylindrical segment 110, and the length of the cylindrical segment 110 of the covering film 11 is greater than the length of the proximal conical segment 111.

[0088] The proximal end of the proximal conical segment 111 is provided with a connecting ring 16 fixedly connected to the outer wall of the catheter 2, thereby realizing the fixed connection of the distal end 18 of the covering film 11. The connecting ring 16 can be fixedly connected to the catheter 2 by means of adhesion, or heat fusion, or crimping. The connecting position of the covering film 11 and the catheter 2 or the position of the connecting ring 16 is located on the proximal side of the proximal bearing chamber 7.

[0089] Among them, part of the blood outlet 21 is located in the proximal conical segment 111, and the other part of the blood outlet 20 is located in the cylindrical segment 110. The plurality of blood outlets 14 are arranged in the circumferential direction. The part of the blood outlet 20 is located in the cylindrical segment 110, thereby forming a centrifugal flow of the output blood at this position, and then the outward flow of the plurality of blood outlets 14 can stabilize the position of the pump body 1 and stabilize the blood flow. The part of the blood outlet 21 is located in the proximal conical segment 111, thereby forming a substantially axial flow of the output blood, and the part of the blood outlet 20 in the cylindrical segment 110 together ensures the flow of the blood outlet 14, avoiding flow loss.

[0090] In order to maintain the structural strength of the front end of the covering film 11 and maintain the stability of the shape structure, at least part of the axial length of the blood inlet 13 gradually decreases in the circumferential width when extending from the distal end to the proximal end.

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

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

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

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

[0095] In the present embodiment, the support member 12 or the single stent is a one-piece structure, and the support member 12 and the covering membrane 11 are separate structures. At least part of the support member 12 is located inside the covering membrane 11 and contacts the inner wall of the supporting covering membrane 11.

[0096] In the radially expanded state of the pump shell 10 without force, the support member 12 is radially constrained by the covering membrane 11 and is not fully expanded. The support member 12 is made of a memory alloy material, and after losing the constraint of the sheath, the support member 12 restores its shape and expands the covering membrane 11 until it is constrained by the covering membrane 11 and cannot continue to expand. At this time, the support member 12 provides a radially outward support force to the covering membrane 11, and the covering membrane 11 relies on its own toughness to resist the deformation of the support member 12 and does not produce tensile deformation, maintaining the stability of the shape.

[0097] It should be noted that the support member 12 of the present application is not limited to a single stent in the covering membrane 11, but can also include multiple stents dispersed at different axial positions to support different parts of the covering membrane 11. For example, there can be a stent supporting the proximal end 17 of the covering membrane 11 to stably support the blood outlet 14 and maintain the stability of the shape of the blood outlet 14, thereby reducing the influence on blood flow.

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

[0099] The support member 12 supports the distal end 18 of the covering 11. Part of the support member 12 is located outside the distal end 18 of the covering 11, and another part of the support member 12 is located inside the covering 11. The impeller 5 is fixedly arranged on the impeller shaft 6, the impeller shaft 6 is rotatably sleeved in the support member 12, and the distal end of the impeller shaft 6 is rotatably supported in the distal end bearing chamber 15. The distal end of the support member 12 is fixedly connected with the distal end bearing chamber 15.

[0100] The support member 12 is in a spindle structure as a whole, and provides a support space for accommodating the impeller 5. The proximal end of the support member 12 is connected with the distal end of the catheter 2. The proximal end of the support member 12 of the pump body 1 is fixedly connected with the distal end of the catheter 2. The proximal end 17 of the covering 11 is fixedly sleeved on the outer wall of the catheter 2 at the side of the proximal end of the support member 12.

[0101] The distal end of the catheter 2 has a proximal end bearing chamber 7, through which a proximal end ring sleeve 125 of the support member 12 is connected. The proximal end bearing chamber 7 is provided with a proximal end bearing for rotatably supporting the driving shaft. The distal end bearing chamber 15 is arranged at the distal end of the driving shaft and rotatably supports the distal end of the driving shaft through a distal end bearing. The distal end of the support member 12 is fixedly connected with the distal end bearing chamber 15. The support member 12 maintains the distance between the proximal end bearing chamber 7 and the distal end bearing chamber 15, thereby providing stable rotatable support for the impeller shaft 6.

[0102] The distal end of the distal end bearing chamber 15 is also fixedly connected with a non-invasive support member 8. The non-invasive support member 8 is a flexible tube structure, which is a flexible protrusion (pigtail or tip member) in the form of a circular arc or a winding shape. Therefore, the flexible end is supported on the inner wall of the heart chamber in a non-invasive or non-injurious manner, so as to separate the suction port (blood inlet 13) of the pump body 1 from the inner wall of the heart chamber, and avoid the suction port of the pump body 1 from being attached to the inner wall of the heart chamber due to the reaction force of the fluid (blood) during the operation of the pump body 1, thereby ensuring the effective area of the pump body 1.

[0103] The pump body 1 is a foldable pump body. In order to reduce the pain of the subject and facilitate the intervention, it is desirable that the size of the pump body 1 is small. However, in order to provide a strong auxiliary function for the subject, it is desirable that the flow rate of the pump body 1 is large, and generally requires a large size of the pump body 1.

[0104] By arranging the foldable pump body 1, the pump body 1 has a small folded size and a large unfolded size, so as to meet the requirements of reducing the pain of the subject and facilitating the intervention during the intervention / transportation, and providing a large flow rate.

[0105] From the above, the design of the multi-mesh, especially the diamond mesh, of the support member 12 can achieve better folding, and the memory characteristics of the nickel-titanium alloy can be used to achieve unfolding.

[0106] The blades 50 are made of a flexible elastic material, and store energy when being folded. When the external constraint is removed, the blades 50 are unfolded by releasing the stored energy.

[0107] The pump body 1 is folded by means of external constraint, and is unfolded automatically when the constraint is removed. In the present embodiment, the "folded state" refers to the state that the pump body 1 is radially constrained, that is, the state that the pump body 1 is compressed radially to the minimum radial size by external pressure. The "unfolded state" refers to the state that the pump body 1 is not radially constrained, that is, the state that the stent and the impeller 5 are unfolded radially to the maximum radial size.

[0108] The external constraint is applied by a folding sheath (not shown) which is sleeved on the catheter 2. When the folding sheath moves forward outside the catheter 2, the pump body 1 is accommodated in the folding sheath, and is forced to fold. When the folding sheath moves backward, the radial constraint on the pump body 1 is removed, and the pump body 1 is unfolded automatically.

[0109] As described above, the folding of the pump body 1 is realized by the radial constraint force applied by the folding sheath. The impeller 5 is accommodated in the pump shell 10, and therefore, in essence, the folding process of the pump body 1 is that the folding sheath applies a radial constraint force to the pump shell 10, and the pump shell 10 is compressed radially to apply a radial constraint force to the impeller 5.

[0110] That is, the pump shell 10 is directly folded by the folding sheath, while the impeller 5 is directly folded by the pump shell 10. As described above, the impeller 5 is elastic. Therefore, although in the folded state, the impeller 5 is always inclined to unfold radially due to the stored energy, and further, the impeller 5 will contact the inner wall of the pump shell 10 and apply a counterforce to the pump shell 10.

[0111] When the constraint of the folding sheath is removed, the pump shell 10 is unfolded by the support of the elastic coating 11 due to the memory characteristics of the pump shell 10, and the impeller 5 is unfolded by releasing the stored energy. In the unfolded state, the outer diameter of the impeller 5 is smaller than the inner diameter of the pump shell 10.

[0112] In this way, the radial outer end of the impeller 5 (that is, the blade tip of the blade 50) is spaced apart from the inner wall of the pump shell 10 (specifically, the inner wall of the stent), and the spacing is the pump gap. The existence of the pump gap enables the impeller 5 to rotate without obstruction, and without bumping.

[0113] In addition, it is desirable that the pump gap size is small and maintained for fluid mechanics. In the present embodiment, the outer diameter of the impeller 5 is slightly smaller than the inner diameter of the support member 12, so that the pump gap is as small as possible while satisfying the condition that the impeller 5 does not hit the wall during rotation. The main means for maintaining the pump gap is the support strength provided by the support member 12 and the tensile deformation resistance of the coating film 11, which can resist the effect of the back pressure of the fluid (blood) without excessive deformation, thereby maintaining the shape of the pump housing 10 stable, and the pump gap is also maintained stable.

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

[0115] During the process of inserting the pump body 1 into the left ventricle, the pump body 1 is in a radially constrained state (folding 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 its memory characteristics and the blades 50 of the impeller 5 release the stored energy, so the pump body 1 automatically assumes its unconstrained shape (unfolding state).

[0116] Conversely, when the pump body 1 needs to be removed from the subject's body after completing the work, the pump body 1 is folded by the folding sheath, and after the pump body 1 is completely removed from the subject's body, the constraint of the pump body 1 by the folding sheath is removed, so that the pump body 1 returns to the natural state with the minimum stress, that is, the unfolding state.

[0117] The above only describes several embodiments of the present application, and those skilled in the art can make various modifications or changes to the embodiments of the present application according to the disclosed content of the application document without departing from the spirit and scope of the present application.

Claims

1. A pump body for an interventional catheter pump, the pump body being deliverable to a desired location in a heart to pump blood; comprising: A pump housing having a blood inlet and a blood outlet, an impeller housed in the pump housing and configured to provide a motive force for blood flow; the pump housing comprising at least a membrane defining a blood flow channel; The pump body comprises a radially collapsed state and a radially expanded state, and is operable to switch between the radially collapsed state and the radially expanded state; The membrane is configured to not undergo tensile deformation when the pump housing is in the radially expanded state compared to an unstressed state; The pump housing further comprises a support member configured to support the expanded membrane; the radially expanded state comprises a natural expanded state corresponding to when the impeller is not rotating, and a working state corresponding to when the impeller is rotating; The membrane is configured such that a critical point stress causing the membrane to undergo tensile deformation is greater than or equal to a force exerted by the support member on the membrane when the pump housing is in the natural expanded state; the critical point stress causing the membrane to undergo tensile deformation is greater than or equal to a force exerted by a blood back pressure on the membrane due to rotation of the impeller when the pump body is in a maximum working condition; the blood back pressure exerted on the membrane due to rotation of the impeller in the working state causes at least partial flattening of a fold of the membrane; the flattening of the fold causes an increase in a diameter of the membrane.

2. A pump body for an interventional catheter pump, the pump body being deliverable to a desired location in a heart to pump blood; comprising: A pump housing having a blood inlet and a blood outlet, an impeller housed in the pump housing and configured to provide a motive force for blood flow; the pump housing comprising at least a membrane defining a blood flow channel; The pump body comprises a radially collapsed state and a radially expanded state, and is operable to switch between the radially collapsed state and the radially expanded state; The pump body comprises a radially collapsed state and a radially expanded state, and is operable to switch between the radially collapsed state and the radially expanded state; The pump housing further comprises a support member configured to support the expanded membrane; the radially expanded state comprises a natural expanded state corresponding to when the impeller is not rotating, and a working state corresponding to when the impeller is rotating; 3. The pump body of claim 1 or 2, wherein, The membrane is configured such that a critical point stress causing the membrane to undergo tensile deformation is greater than or equal to a force exerted by the support member on the membrane when the pump housing is in the natural expanded state; the critical point stress causing the membrane to undergo tensile deformation is greater than or equal to a force exerted by a blood back pressure on the membrane due to rotation of the impeller when the pump body is in a maximum working condition; the blood back pressure exerted on the membrane due to rotation of the impeller in the working state causes at least partial flattening of a fold of the membrane; the flattening of the fold causes an increase in a diameter of the membrane.

4. The pump body of claim 2, wherein, The flattening of the fold causes an increase in the diameter of the membrane at a rate of no more than 3%.

5. The pump body of claim 2, wherein, The pump housing comprises at least a sub-process of no increase in the diameter of the membrane during the transition from the natural expanded state to the working state.

6. The pump body of claim 1 or 2, wherein, The membrane is configured to not undergo tensile deformation when the pump housing is in the natural expanded state or the working state compared to an unstressed state. The membrane is configured such that a material strength of the membrane itself is sufficient to resist an outward expansion force of the support member, and thus the membrane has a circumferential tensile deformation of 0 when the pump housing is switched from the radially collapsed state to the natural expanded state.

7. The pump body of claim 6, wherein, The cover film is configured to have a material strength sufficient to resist a force exerted thereon by blood back pressure due to rotation of the impeller, and a circumferential tensile deformation amount of the cover film is 0 when the pump body is switched from the natural expansion state to the working state.

8. The pump body of claim 6, wherein, The cover film has a diameter in the working state of the pump body that is greater than a diameter in the natural expansion state of the pump body.

9. A pump body for an interventional catheter pump, the pump body being deliverable to a desired location in a heart to pump blood; comprising: A pump body having a blood inlet and a blood outlet, an impeller housed in the pump body and configured to provide power for blood flow; the pump body comprising at least a cover film defining a blood flow channel; The pump body comprises a radially collapsed state suitable for delivery in a subject's vasculature, a natural expansion state corresponding to the impeller not rotating, and a working state corresponding to the impeller rotating; The cover film has a diameter in the working state of the pump body that is greater than a diameter in the natural expansion state of the pump body. The pump body further comprises a support member for supporting the expansion of the cover film; the cover film is configured to have a critical point stress causing tensile deformation greater than or equal to a force exerted thereon by the support member when the pump body is in the natural expansion state; the critical point stress causing tensile deformation of the cover film is greater than or equal to a force exerted thereon by blood back pressure due to rotation of the impeller when the pump body is in a maximum working condition.

10. The pump body of claim 9, wherein, In the natural expansion state, the support member is radially constrained by the cover film and is not fully expanded.

11. The pump body of claim 9, wherein, In the natural expansion state, the support member has a contact support portion in contact with the cover film; in the working state, at least a portion of the contact support portion is spaced apart from the cover film.

12. The pump body of claim 9, wherein, The cover film comprises a cylindrical segment, a proximal tapered segment disposed at a proximal end of the cylindrical segment; the blood inlet extends from the proximal tapered segment to the cylindrical segment; wherein part of the blood outlet is located in the proximal tapered segment, and another part of the blood outlet is located in the cylindrical segment; the blood inlet gradually decreases in circumferential width from a distal end to a proximal end of at least part of the axial length; or, the length of the blood outlet in the part of the proximal tapered segment is greater than the length of the blood outlet in the part of the cylindrical segment.

13. The pump body of claim 1 or 2 or 9, wherein, The material of the cover film is TPU or PTFE or PEBAX.

14. An interventional catheter pump, wherein, Comprising: A catheter; A drive shaft passing through the catheter; A power assembly connected to the proximal end of the drive shaft; The pump body of any one of claims 1-13, the impeller of the pump body being connected to the distal end of the drive shaft.

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