CN116271501B

CN116271501B - Catheter pump

Info

Publication number: CN116271501B
Application number: CN202310459663.9A
Authority: CN
Inventors: 屠攀; 颜翊凡; 陈伟
Original assignee: Xinqing Medical Suzhou Co ltd
Current assignee: Xinqing Medical Suzhou Co ltd
Priority date: 2023-04-26
Filing date: 2023-04-26
Publication date: 2024-06-11
Anticipated expiration: 2043-04-26
Also published as: CN116271501A

Abstract

Disclosed is a catheter pump comprising: a catheter, a pump head that pumps blood through the catheter to a desired location of the heart; the pump head comprises a pump shell with a blood inlet and a blood outlet, and an impeller accommodated in the pump shell; the impeller rotates to draw blood into the pump housing from the blood inlet and pump the blood out of the blood outlet; the pump housing includes a stand that is operable to switch between a radially collapsed state and a radially expanded state. A plurality of meshes are distributed on the main body of the bracket, each mesh comprises a first edge and a second edge, the first edge and the second edge at the same axial position are sequentially connected end to end along the circumferential direction to form a sawtooth ring, and the sawtooth ring is provided with a plurality of far-end vertexes and a plurality of near-end vertexes which are distributed along the circumferential direction in a staggered manner. The plurality of sawtooth rings are connected in an axial arrangement, a part of the sawtooth rings are aligned in an axial direction and adjacent distal vertexes are connected with the proximal vertexes so as to realize fixed connection of the adjacent two sawtooth rings, and the part of the sawtooth rings are aligned in the axial direction and the adjacent distal vertexes and the proximal vertexes are in an unconnected empty state.

Description

Catheter pump

Technical Field

The present disclosure relates to the field of medical devices, and in particular to a catheter pump.

Background

Catheter pumps are classified into non-collapsible and collapsible. Among other things, collapsible catheter pumps have less trauma during intervention and thus have the benefit of more convenient and faster use.

One core component that enables the catheter pump to be collapsible is a stent. During pumping, a greater stiffness of the stent is desirable to maintain the pump gap. When the support is folded, the rigidity of the support is expected to be low, so that the support is convenient to fold. These two even opposite technical requirements present a great challenge to the structural design of the stent.

The stent provided by CN102805885B improves the overall support of the stent by arranging the openings of the inlet and outlet portions of the blood to be large or sparse by arranging the openings of the pump portion surrounding the impeller to be small or dense. However, it is obvious that this structural design also results in a large folding force of the bracket, which is not easy to fold.

Therefore, how to fold the stent of the foldable catheter pump with a small force is a problem to be solved.

Disclosure of Invention

In view of the shortcomings of the prior art, it is an object of the present disclosure to provide a catheter pump that can achieve smooth collapse of a stent with less force.

A catheter pump comprising: a catheter, a pump head that pumps blood through the catheter to a desired location of the heart; the pump head includes: a pump casing having a blood inlet and a blood outlet, and an impeller housed in the pump casing; the impeller is driven to rotate to draw blood into the pump housing from the blood inlet and then out the blood outlet.

The pump housing includes a stand that is operable to switch between a radially collapsed state and a radially expanded state. In the radially expanded state, the stent includes a generally cylindrical main body portion, and generally tapered inlet and outlet portions at axially distal and proximal ends of the main body portion, respectively. The main body part is provided with a plurality of meshes, each mesh comprises two oppositely arranged first edges and two oppositely arranged second edges, the first edges and the second edges at the same axial position are sequentially connected end to end along the circumferential direction to form a sawtooth ring, and the sawtooth ring is provided with a plurality of far-end vertexes and a plurality of near-end vertexes which are staggered along the circumferential direction. The plurality of sawtooth rings are connected in an axial arrangement, a part of the sawtooth rings are aligned in an axial direction and adjacent distal vertexes are connected with the proximal vertexes so as to realize fixed connection of the adjacent two sawtooth rings, and the part of the sawtooth rings are aligned in the axial direction and the adjacent distal vertexes and the proximal vertexes are in an unconnected empty state.

Preferably, the distal and proximal apices in the empty state are axially spaced apart.

Preferably, the portions are axially aligned and adjacent distal and proximal apices are indirectly connected by an axial connecting rod.

Preferably, the portions are axially aligned and adjacent distal and proximal apices are directly connected.

Preferably, in the two zigzag rings located at the axially most distal end, part of the axially aligned and adjacent distal and proximal apices are in a free state, and the rest of the axially aligned and adjacent distal and proximal apices are connected by an axial connecting rod.

Preferably, in the two zigzag rings located axially most proximal, part of them are axially aligned and adjacent distal and proximal apices are in a free state, the rest of them are axially aligned and adjacent distal and proximal apices are connected by an axial connecting rod.

Preferably, there are also at least two zigzag rings between the most proximal zigzag ring and the most distal zigzag ring, of which at least two zigzag rings each adjacent two zigzag rings are axially aligned and all adjacent distal and proximal apices are connected by an axial connecting rod.

Preferably, the two zigzag rings at the axially most distal end form a first mesh group and the two zigzag rings at the axially proximal end form a second mesh group. In the first mesh group or the second mesh group, there is at least one pair of axially aligned and adjacent distal and proximal apices between two circumferentially adjacent axial connecting rods, which are in a free state.

Preferably, the distal and proximal apices in the free state in the two most proximal serration rings are axially offset from the distal and proximal apices in the free state in the two most distal serration rings.

Preferably, the distal and proximal apices in the free state in the two most proximal serration rings are offset uniformly in the axial direction from the distal and proximal apices in the free state in the two most distal serration rings.

Preferably, the distal and proximal apices in the free state in the two most proximal serration rings differ from the distal and proximal apices in the free state in the two most distal serration rings by 180 °/m in circumferential phase angle, m being the number of proximal or distal free points.

Preferably, a spacing gap is formed between the distal apex and the proximal apex in the empty state, the spacing gap connecting the meshes on both sides in the circumferential direction; the main body portion includes a closed mesh having an opening area smaller than that of the meshes included in the inlet portion and the outlet portion, and both side meshes communicating with the gap have an opening area larger than that of the meshes included in the inlet portion and the outlet portion.

Preferably, the distal and proximal apices in the null have greater corner radii than the distal and proximal apices not in the null.

Preferably, the pump head further comprises a coating film arranged outside the bracket. The pump head is switchable between a radially expanded state and a radially collapsed state. The catheter pump further includes an access sheath having an access channel and configured to be partially accessible through the puncture to the vasculature of the subject. When the catheter is threaded into the interventional sheath, the pump head in the radially expanded state enters the interventional channel from the distal end of the interventional sheath by pulling the catheter backward, so that the pump head is switched to the radially collapsed state. The thickness of the wall defining the access channel is between 0.15 and 0.3 mm.

The main body part of the support is aligned along the axial direction, and the adjacent part of the distal end vertex and the proximal end vertex are arranged in a non-connected empty state, which is equivalent to reducing the number of edges of the main body part, so that the rigidity of the main body part can be properly reduced, the folding force of the support is reduced, and the support can be smoothly folded from a radial unfolding state to a radial folding state.

Drawings

FIG. 1 is a schematic view of a structure of a stent provided in one embodiment of the present disclosure;

FIG. 2 is a schematic view of a stent according to another embodiment of the present disclosure;

FIG. 3 is a schematic diagram of a catheter pump provided in accordance with another embodiment of the present disclosure;

FIG. 4 is a partial cross-sectional view of FIG. 3;

FIG. 5 is a schematic view of the catheter pump with an insertion sheath of the introducer deployed;

FIG. 6 is a schematic diagram showing the phenomenon of "dog bones" of the prior art when the stent is subjected to a radial external force;

FIG. 7 is a cross-sectional view of the stent in the vicinity of the first mesh group/second mesh group;

fig. 8A to 8C are schematic diagrams showing distribution of the proximal and distal vertices in the empty state.

Reference numerals illustrate:

1000. A catheter pump; 100. a power assembly; 101. a housing; 200. a working assembly; 201. a conduit; 202. a drive shaft; 2021. a flexible shaft; 2022. a hard shaft; 204. driving the catheter handle; 205. a pump head; 2051. a pump housing; 2051a, a blood inlet; 2051b, blood outlet; 20511. a bracket; 20512. coating a film; 2052. an impeller; 20521. a hub; 20522. a blade; 206. a proximal bearing chamber; 207. a distal bearing chamber; 208. a proximal bearing; 209. a distal bearing; 210. a non-invasive support; 211. a stop; 212. limiting; 11. a main body portion; 12. an inlet portion; 121. a closed mesh of the inlet portion; 122. open mesh of the inlet portion; 13. an outlet portion; 131. a closed mesh of the outlet portion; 132. an open mesh of the outlet portion; 14. a mesh; 15. a first edge; 16. a second edge; 17. a saw tooth ring; 18. a distal vertex; 19. a proximal vertex; 20. a spacing gap; 21. an axial connecting rod; 24. a first set of cells; 25. a second set of cells; 26. a third set of cells; 22. a distal connection; 221. the far end is connected with the supporting leg; 222. a distal shaft; 223. a third lever portion; 224. a fourth lever portion; 225. a remote transition unit; 226. a second extension; 23. a proximal connection; 231. the proximal end is connected with the supporting leg; 232. a proximal shaft; 233. a first lever portion; 234. a second lever portion; 235. a proximal transition unit; 236. a first extension; 5. an introducer; 9. an interventional sheath; x, axial direction.

Detailed Description

The present invention will be described in detail below with reference to specific embodiments shown in the drawings. These embodiments are not intended to limit the invention and structural, methodological, or functional modifications of these embodiments by one of ordinary skill in the art are included within the scope of the present disclosure.

The terms "proximal", "distal" and "anterior", "posterior" as used in this disclosure are relative to a clinician manipulating the catheter pump of this embodiment. The terms "proximal", "posterior" and "anterior" refer to portions relatively closer to the clinician, and the terms "distal" and "anterior" refer to portions relatively farther from the clinician. For example, the extracorporeal portion is at the proximal or rear end and the intervention into the intracorporal portion is at the distal or front end.

In the present invention, the terms "connected," "connected," and the like should be construed broadly unless otherwise specifically indicated and defined. For example, the device can be fixedly connected, detachably connected, movably connected or integrated; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In addition, the technical features of the different embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.

Referring to fig. 1 and 2, a stent 20511 of an embodiment of the present disclosure is operable to switch between a radially collapsed state and a radially expanded state. In the radially expanded state, the holder 20511 includes a substantially cylindrical main body portion 11, and substantially tapered inlet and outlet portions 12 and 13 located at distal and proximal ends, respectively, of the main body portion 11 in the axial direction X.

The main body 11 is provided with a plurality of meshes 14, and the meshes 14 comprise two oppositely arranged first edges 15 and two oppositely arranged second edges 16. The first edges 15 and the second edges 16 at the same position in the axial direction X are sequentially connected end to end in the circumferential direction to form a sawtooth ring 17, the sawtooth ring 17 is provided with a plurality of distal vertexes 18 and a plurality of proximal vertexes 19 which are staggered in the circumferential direction, the sawtooth ring 17 is arranged in the axial direction X, partial sawtooth rings are aligned in the axial direction X, and adjacent distal vertexes 18 and proximal vertexes 19 are connected to realize fixed connection of two adjacent sawtooth rings 17 in the axial direction. Also, the stent 20511 has a portion aligned along the axial direction X and adjacent distal and proximal apices 18, 19 are in an unconnected, empty state. The distal apex 18 and the proximal apex 19 in the empty state are spaced apart in the axial direction X, and a spacing gap 20 is formed therebetween, and the spacing gap 20 communicates the mesh holes 14 on both circumferential sides thereof.

As shown in fig. 1, the sawtooth ring 17 is formed by connecting a first edge 15 and a second edge 16 which are positioned at the same axial position in sequence end to end along the circumferential direction, and the first edge 15 and the second edge 16 are connected at an angle, so as to form a circumferential continuous ring (shown by a dotted line frame in fig. 1) in a tooth shape or a partial W shape.

In one embodiment, the distal apex 18 and the proximal apex 19, which are partially opposite in the axial direction X, may be indirectly fixedly connected by an axial connecting rod 21, and both ends of the axial connecting rod 21 are respectively connected to the distal apex 18 and the proximal apex 19. At this time, the mesh 14 (closed mesh 14) is surrounded by 2 first edges 15, 2 second edges 16, and 2 axial connecting rods 21, and is substantially hexagonal. Since the corresponding distal and proximal apices 18, 19 are indirectly connected by the axial connecting rod 21, the distal and proximal apices 18, 19 in the empty state are axially spaced apart due to the absence of the axial connecting rod 21. At this time, the structures of all the serration rings 17 may be identical (as shown in fig. 1). Of course, the structure of the serrated ring 17 may not be identical, i.e., the distal and proximal apices 18, 19 in the empty state have larger fillet radii, as shown in fig. 2, making the distal and proximal apices 18, 19 in the empty state shorter.

In other alternative embodiments, the distal and proximal apices 18, 19, which are partially opposite in the axial direction X, may also be directly connected, without having to be connected by means of the axial connecting rod 21 described above. At this time, the mesh 14 (closed mesh 14) is surrounded by 2 first edges 15 and 2 second edges 16, and is substantially quadrangular (not shown). As described below, when the distal and proximal apices 18, 19 are directly connected, the distal and proximal apices 18, 19 in the idle state may be separated in the axial direction X by providing a large rounded corner (as shown in fig. 2) to make the distal and proximal apices 18, 19 in the idle state shorter.

In the embodiment where the distal apices 18 and the proximal apices 19 are connected by axial connecting rods 21, the axial connecting rods 21 isolate the mesh 14 on both sides in the circumferential direction thereof. The axial connecting rod 21 extends in the axial direction X, connects two axially adjacent serration rings 17, connects the originally isolated serration rings 17 to each other, and connects the inlet portion 12, the outlet portion 13, and the main body portion 11 together while forming the main body portion 11 of the bracket 20511, thereby forming the complete bracket 20511. The structural design of the distal apices 18 and the proximal apices 19 in the empty state is matched, so that the support 20511 has better folding compliance and better rigidity.

Further, in order not to cause a decrease in the overall stiffness of the stent 20511 due to the structural design in which the distal apex 18 and the proximal apex 19 are in a vacant state, the main body portion 11 may be similarly designed with a small mesh as compared with the inlet portion 12 and the outlet portion 13. That is, the opening area of the closed mesh 14 (such as the mesh 14 of the third mesh group 26, hereinafter) included in the main body portion 11 is smaller than the opening areas of the meshes included in the inlet portion 12 and the outlet portion 13.

As shown in fig. 1, wherein the mesh openings of the inlet portion 12 and the outlet portion 13 comprise closed mesh openings 121, 131, and also open mesh openings 122, 132. The opening areas of the closed mesh 14 of the main body 11, the closed mesh 121 of the inlet 12 and the closed mesh 131 of the outlet 13 are calculated as closed areas surrounded by the openings. While the areas of the open mesh openings 122, 132 of the inlet and outlet portions 12, 13 are calculated as the portions of the stent 20511 other than the connection interfaces (shown by broken lines in fig. 1) of the proximal and distal connection members, respectively, at both ends thereof. That is, the open mesh 122, 132 performs area calculation with the broken line as a boundary on the open side.

Specifically, as described below, the proximal connection member may be a proximal bearing housing 206 or a distal portion of the catheter, and the distal connection member may be a distal bearing housing 207 or a atraumatic support 210. The proximal and distal connection portions 23, 22 of the stent 20511 are connected to proximal and distal connection members, respectively, and the proximal connection legs 231 defining the open mesh 122 have a portion connected to the proximal connection member. Likewise, distal connecting legs 221 defining open cells 132 have a portion connected to the distal connecting member. This results in the open cells 122, 132 being partially blocked by the corresponding connecting members, respectively, with the dashed lines in fig. 1 being the locations where the open cells 122, 132 are substantially blocked. The portions of the open mesh 122, 132 that are occluded overlap the corresponding connecting members, so blood does not circulate but only through the portions that are not occluded. Thus, the open area of the open mesh openings 122, 132 is calculated as the area outside the dotted line, that is, the area of the portion of the open mesh openings 122, 132 through which blood can actually flow. Specifically, in fig. 1, the open area of the open mesh 122 is the area of the portion of the right-side broken line to the left, and the open area of the open mesh 132 is the area of the portion of the left-side broken line to the right.

The two side meshes communicated by the interval gap 20 form a large mesh like an "8" shape, and the opening area of the "8" shape large mesh is larger than the opening area of the meshes included in the inlet portion 12 and the outlet portion 13.

The first edge 15, the second edge 16 and the axial connecting rod 21 are linear as a whole, and the lengths of the first edge 15 and the second edge 16 are equal. On the same serrated ring 17, a plurality of distal apices 18 are coplanar and the face is perpendicular to the axial direction X, and a plurality of proximal apices 19 are coplanar and the face is perpendicular to the axial direction X. In the adjacent two serration rings 17, the line connecting the distal apex 18 of one serration ring 17 and the proximal apex 19 of the other serration ring 17 is parallel to the axial direction X.

In the two zigzag rings 17 located at the most distal end in the axial direction X, part of the distal and proximal apices 18 and 19 opposed in the axial direction X are left in a vacant state, and the rest of the distal and proximal apices 18 and 19 opposed in the axial direction X are connected by an axial connecting rod 21. The two zigzag rings 17 located at the most distal end in the axial direction X form a first mesh group 24, the first mesh group 24 being located at the end of the main body portion 11 near the inlet portion 12. By providing both the spacing gap 20 and the axial connecting rod 21 within the first mesh group 24, rigidity of the bracket 20511 can be ensured while reducing the folding force.

Likewise, in the two zigzag rings 17 located at the most proximal end in the axial direction X, part of the distal apexes 18 and the proximal apexes 19 opposed in the axial direction X are left in a vacant state, and the rest of the distal apexes 18 and the proximal apexes 19 opposed in the axial direction X are connected by the axial connecting rod 21. Two zigzag rings 17 located at the proximal end in the axial direction X form a second mesh group 25, the second mesh group 25 being located at the end of the main body portion 11 near the outlet portion 13. By providing both the spacing gap 20 and the axial connecting rod 21 in the second mesh group 25, rigidity of the bracket 20511 can be ensured while reducing the folding force.

As shown in fig. 7, 8A to 8C, the distribution of the distal and proximal apices 18 and 19 in the empty state is shown. In fig. 8A to 8C, the broken line ring represents the distal vertex 18 and the proximal vertex 19 in the empty state, and the solid line ring represents the distal vertex 18 and the proximal vertex 19 in the connected state, respectively.

In some embodiments, as shown in fig. 8B, at least one pair of axially opposed distal and proximal apices 18, 19 are left free between two axially adjacent tie bars 21 in the first or second mesh group 24, 25. That is, the interval gap 20 and the axial connecting rod 21 are sequentially arranged in the circumferential direction. Or the axial connecting rods 21 are arranged one at a time at intervals 20. This also means that the first set of cells 24 and the second set of cells 25 comprise all cells 14 that are large cells like an "8" shape, but not closed small cells.

In other embodiments, there may be multiple pairs (e.g., two, three, or other pairs, etc.) of axially X-opposed distal and proximal apices 18, 19 between two axially-oriented connecting rods 21 circumferentially arranged in either the first or second mesh set 24, 25. That is, there may be two, three, or other number of spacing gaps 20 between two axially oriented connecting rods 21 circumferentially arranged.

Specifically, as shown in fig. 7 and 8A, there are 4 pairs of distal vertexes 18 and proximal vertexes 19 in the empty state in the first mesh group 24 or the second mesh group 25. Fig. 8C illustrates that there are 2 pairs of distal and proximal apices 18 and 19 in a null state. In both embodiments, a plurality of axial connecting rods 21 (3 and 7, respectively) are spaced between the distal and proximal apices 18, 19, respectively, in the empty state. This also means that the first set of cells 24 and the second set of cells 25 comprise all cells 14, including both large cells like an "8" shape and small cells that are closed.

In this embodiment, between the most proximal and distal toothed rings 17, 17 there are also at least two adjacent toothed rings 17, of which at least two toothed rings 17, all distal and proximal apices 18, 19 opposite in the axial direction X are connected by an axial connecting rod 21. The at least two serration rings 17 are located between the axially most proximal serration ring 17 and the axially most distal serration ring 17, and the at least two serration rings 17 form a third mesh group 26, the third mesh group 26 being located between the first mesh group 24 and the second mesh group 25.

By providing only axial connecting rods 21 within the third mesh group 26, without providing the spacing gaps 20, a relatively large stiffness of the rack 20511 in the middle region can be ensured. In the cells 14 of the third cell group 26, one axial connecting rod 21 is connected between one first edge 15 and one second edge 16, and the other axial connecting rod 21 is connected between the other first edge 15 and the other second edge 16. The first edge 15, the second edge 16 and the axial connecting rod 21 enclose a closed mesh 14.

It has been found that the regions of greatest folding force are located at both ends of the main body 11, not at the middle of the main body 11. Therefore, the space gaps 20 are provided in the first mesh group 24 and the second mesh group 25 at both ends of the main body portion 11, so that the folding force can be reduced more effectively without significantly reducing the rigidity of the bracket 20511.

In this embodiment, the "stiffness" is embodied by the ability of the stent 20511 to deform against radially outward forces in a radially deployed state (particularly an operational state). The greater the stiffness of the stent 20511, the better the ability to resist deformation by radially outward forces, or the less the degree of radially inward deformation will occur with the same radially outward force. Conversely, the less stiff the stent 20511, the less resistant to deformation by radially outward forces, or the greater the extent to which radially inward deformation occurs with the same radially outward forces.

Specifically, as described below, when the pump head of the catheter pump employing the support 20511 of the present embodiment is involved in the ventricle and the impeller 2052 is rotated to pump blood, there is a possibility that the pump head swings in the ventricle to laterally hit the inner wall of the ventricle due to some cause such as patient movement or heart action. If the carrier 20511 is poorly rigid, such lateral impact may cause radial recession of the carrier 20511, which in turn may cause the rotating impeller 2052 to scrape against the carrier 20511. This unexpected situation is undesirable because it may cause the impeller 2052 to wrap around the support 20511, thereby causing the impeller 2052 to be forced out and the pump to fail.

Since the most axially opposite ends of the main body portion 11 of the holder 20511 are connected to the inlet portion 12 and the outlet portion 13, respectively, the width of the rod included in the inlet portion 12 and the outlet portion 13 is generally large. That is, the inlet portion 12 and the outlet portion 13 are more "strong". Therefore, the axially most end meshes or rods of the main body 11 are supported by the inlet and outlet portions 12, 13 having greater rigidity, and the axial connecting rods 21 are selectively removed from the first and second end mesh groups 24, 25 without significantly impairing the overall rigidity of the bracket 20511.

Further, since the holder 20511 is folded from the end, the rigidity of the axial end of the main body 11 is high, which is disadvantageous for folding the holder 20511. Therefore, with the above-described arrangement, the rigidity of the axial end portion of the main body portion 11 is appropriately weakened, which is advantageous for folding the bracket 20511.

As described above, with respect to the main body portion 11 only, since the mesh or rod at the extreme ends thereof in the axial direction is supported by the inlet portion 12, the outlet portion 13 which are relatively rigid, it is possible to have relatively high rigidity, while the mesh or rod at the intermediate portion can be supported only by the mesh or rod at the extreme ends. Therefore, the rigidity of both ends of the main body 11 is greater than that of the intermediate portion. It has been found that if the two ends of the main body 11 and the middle portion are designed to have the same grid structure or density, the main body 11 will exhibit a "dog bone" phenomenon (dog bone) in which the middle portion is concave and the two end portions are substantially unchanged when the pump head is subjected to radially external force, as shown in fig. 6. Since the impeller 2052 is mostly located in the middle region of the main body portion 11, the "dog bone" phenomenon is liable to cause the above-described problem in which the impeller 2052 is wound around the bracket 20511.

The structural design is adopted, and the design that the middle part of the main body part 11 is provided with small closed meshes and the two sides are provided with small closed meshes and large meshes is matched, namely, the scheme that the grid structures at the two ends of the main body part 11 are properly weakened and the middle grid structure is properly reinforced is adopted, so that the overall rigidity of the main body part 11 is uniform, and the phenomenon of dog bones is avoided.

In an alternative embodiment, as shown in fig. 1 and 2, the stent 20511 comprises four zigzag rings 17, all of the distal apices 18 and proximal apices 19 of the middle two zigzag rings 17 that are opposite in the axial direction X are connected by an axial connecting rod 21. The four zigzag rings 17 form a first mesh group 24, a third mesh group 26 and a second mesh group 25 in this order from the distal end to the proximal end, the first mesh group 24 and the third mesh group 26 sharing one zigzag ring 17, and the second mesh group 25 and the third mesh group 26 sharing another zigzag ring 17.

Of course, the number of the serration rings 17 is not limited to four. For example, the number of the zigzag rings 17 may be 5, 6 or … n (n is greater than 4), and the number of the mesh groups formed is (n-1). As described above, in the case where the number of the zigzag rings 17 is more than four, the distal and proximal apices 18 and 19 in the vacant state exist only in the two mesh groups at the most proximal and distal ends, and the middle mesh group between the two mesh groups at the most proximal and distal ends does not exist in the distal and proximal apices 18 and 19 in the vacant state.

As shown in fig. 8A-8C, the left side of each figure is the empty space of the distal apices 18 in the first mesh group 24 and the right side is the empty space of the proximal apices 19 in the second mesh group 25. In some embodiments, the distal and proximal apices 18, 19 in the most proximal two zigzag rings 17 are offset in the axial direction X from the distal and proximal apices 18, 19 in the most distal two zigzag rings 17. That is, the spacing gap 20 (abbreviated as distal end free point) of the first mesh group 24 and the spacing gap 20 (abbreviated as proximal end free point) of the second mesh group 25 are offset in the axial direction X.

Preferably, the staggering is a uniform staggering. Specifically, the circumferential phase angles of the proximal and distal nulls differ by 180 °/m, where m is the number of proximal or distal nulls.

For example, as illustrated in fig. 8A to 8C, the number of distal vertexes 18 and proximal vertexes 19 is 16, and the 16 distal vertexes 18 and proximal vertexes 19 are sequentially numbered 1 to 16. Where the distal free points are 4 as illustrated in fig. 8A, the distal apices 18 numbered 1, 5, 9, 13 in the first mesh group 24 are free. Correspondingly, the proximal apices 19 numbered 3, 7, 11 in the second mesh group 25 are free, the circumferential phase angles of the proximal free and distal free being 45 °.

Similarly, where the distal free points are 8 as illustrated in fig. 8B, the distal apices 18 numbered 1,3, 5, 7, 9, 11, 13, 15 in the first mesh group 24 are free, and the proximal apices 19 numbered 3, 7, 11, 115 in the second mesh group 25 are free, the proximal free points differing from the distal free points by 22.5 ° in circumferential phase angle. When the distal free points are 2 as illustrated in fig. 8C, the distal apexes 18 numbered 1, 9 in the first mesh group 24 are free, the proximal apexes 19 numbered 5, 13 in the second mesh group 25 are free, and the circumferential phase angles of the proximal and distal free points differ by 90 degrees

By staggering the proximal and distal free points axially, the occurrence of the free points in the same axial direction of the main body 11 can be avoided, and further, the occurrence of an area with obviously weakened supporting rigidity of the main body 11 can be avoided. By uniformly staggering the empty points, the weakened areas of the main body 11 can be uniformly distributed, and the supporting rigidity of the main body 11 can be balanced as much as possible.

As shown in connection with fig. 1, the proximal end of the outlet portion 13 is provided with a proximal connection portion 23. The proximal connection portion 23 includes a plurality of proximal connection legs 231 circumferentially spaced apart, and the proximal connection legs 231 are configured to connect with a catheter or proximal bearing housing to provide a secure connection of the support 20511 to the catheter.

As in the known embodiment provided in publication No. CN114588533a, the distal connection structure of the stent is prior art with discrete legs (in particular, a plurality of legs are arranged at intervals along the circumferential direction). However, in order to maintain a high strength fixed connection with the catheter or proximal bearing housing, the proximal connection of the stent is most commonly a circumferentially continuous collar structure. The reason is that the circumferentially continuous loop structure does not lift up due to the lever principle when the pump head is folded, and thus the fixed connection relation with the catheter is always maintained. In view of this, the proximal connection structure of the stent cannot be constructed with discrete legs that are the same or similar to the distal connection structure.

In addition, in consideration of the fact that the process is as simple as possible, a prefabricated pipe can be used for carving or laser cutting to manufacture the support, and the connecting ring sleeve is arranged at the proximal end of the support to realize connection and fixation with the pipe or the proximal bearing chamber, so that the diameter of the sleeve-shaped connecting ring sleeve part is the same as that of the pipe prefabricated to form the support part.

The prefabricated pipe has a smaller diameter due to the small size that is ultimately to be met for ease of placement and intervention. Meanwhile, the requirement of the final larger unfolding diameter of the bracket part is met, the carving amount is increased, the rod width of the bracket is smaller, and the rigidity is weaker. Conversely, if the strut width and stiffness of the stent meet the requirements, the amount of engraving removal is less, resulting in a smaller stent deployment diameter.

In addition, prefabricated pipes with larger diameters can be used for carving to manufacture the bracket, and finally, the connecting ring sleeve at the near end is thinned. But this results in waste, high cost and complex process.

The above problems can be better solved by arranging a plurality of proximal connecting legs 231 which are circumferentially arranged at intervals, that is, a plurality of proximal connecting legs 231 are distributed, instead of the connecting ring sleeve which is at least partially continuous in the circumferential direction in the prior art. The method comprises the following steps:

As mentioned above, if a circumferentially continuous attachment collar structure is used (the attachment collar is the proximal portion of the preformed tube), the diameter of the attachment collar is the diameter of the stent after collapsing. That is, the diameter of the stent 20511 after collapsing is limited by the diameter of the proximal connection collar, i.e., by the diameter of the preformed tube. If the diameter of the prefabricated tube is large, it is difficult to meet the small diameter of the folded bracket 20511, and thus the requirement of the small insertion size of the pump head cannot be met. If the diameter of the preformed tube is small, the large deployment diameter and deployment support stiffness of the stent 20511 cannot be met at the same time, although the small collapsed and intervening dimensions of the stent 20511 can be met. The reason is that: in order to satisfy a large deployment diameter, the amount of the tube to be cut and removed is large, and the width of the stent 20511, particularly the stem of the main body 11, is small, resulting in a decrease in the support rigidity after deployment. Conversely, to meet a large deployment support stiffness, the width of the stent 20511, and particularly the stem of the main body portion 11, is required to be large, which requires that the amount of tubing cut removal not be too great, but which in turn results in an insufficient deployment diameter of the stent 20511.

In contrast, the stent 20511 of this embodiment no longer employs a circumferentially continuous loop structure at the proximal end, but rather employs a plurality of discrete leg structures that are not connected to one another. Thus, the diameter of the folded stent 20511 is not limited by the diameter of the preformed tube, i.e., the stent can be made by laser cutting from a preformed tube having a relatively large diameter. Since the diameter of the selected prefabricated tube is larger than that of the prior art, the amount of cutting removal of the material is reduced to achieve the same expanded diameter, the rod width of the main body portion 11 of the bracket 20511 is increased, and the supporting rigidity of the bracket 20511 is further improved. Alternatively, to achieve the same support stiffness, the amount of material cut away may be increased, the stem width of the body portion 11 of the stent 20511 reduced, and the deployment diameter of the stent 20511 increased.

It is noted that the bracket 20511 of this embodiment is manufactured by laser cutting an integral body of prefabricated pipe material. That is, in comparison with the prior art, the present embodiment forms the entire structure of the bracket 20511, including the main body 11, the proximal connecting leg 231, and the distal connecting leg 221, by laser cutting, as compared with the main body 11 and the distal connecting leg of the bracket 20511 formed by laser cutting only. Thus, the fabrication process of the bracket 20511 is rather simple.

The bracket 20511 formed in the above manner has a hollow cylindrical structure (in this case, the main body, the proximal connection leg 231, the distal connection leg 221, and the like are not distinguished), and the outer diameters of the respective axial portions are equal. And then shaping the hollow cylindrical structure (the bracket before molding for short) to obtain a final bracket structure. The method comprises the following steps: the support before forming is sleeved on the inner shaping mould, and then the outer shaping mould is sleeved outside the shaping mould (the external outline shape of the inner shaping mould and the inner cavity shape of the outer shaping mould can refer to the support shape as shown in fig. 1 or fig. 2). And then, performing a heat treatment process on the bracket before forming, heating to the phase transition temperature of a bracket material (such as nickel-titanium alloy), preserving heat for a period of time, cooling, and demolding to obtain the final bracket.

Therefore, compared with the prior art, the present embodiment adopts the structure of the proximal end dispersed connection legs, which can ensure that the main body portion 11 of the support 20511 has a larger expansion diameter and support rigidity in the radially expanded state on the premise of meeting the requirement that the main body portion 11 of the support 20511 is small in size in the radially collapsed state. And compared with a bracket with the connecting ring sleeve at the proximal end and engraved by adopting a prefabricated pipe with a larger diameter, the bracket has the advantages of no waste, low cost and simple process.

The proximal connecting leg 231 includes a proximal shaft 232 connected to the outlet portion 13 and a first extension 236 connected to the proximal shaft 232. The proximal shaft 232 extends in the axial direction X and the first extension 236 extends circumferentially such that the first extension 236 is perpendicular to the proximal shaft 232.

The circumferential width of the first extension 236 is greater than the circumferential width of at least a portion of the proximal shaft body 232 such that the proximal connecting leg 231 forms a generally "T" shaped structure for positioning engagement with the groove of the outer wall of the proximal bearing chamber 206 to achieve a secure connection of the support 20511 to the catheter 201.

The proximal shaft 232 includes a first shaft 233 connected to the outlet portion 13, and a second shaft 234 connected at both ends to the first shaft 233 and the first extension 236, respectively. The second stem 234 has a circumferential width that is less than the circumferential width of the first stem 233 and also less than the circumferential width of the first extension 236. Thus, a constriction is formed at the second stem 234 that can mate with a groove in the outer wall of the proximal bearing chamber 206, securing the proximal connecting leg 231 to the proximal bearing chamber 206.

A proximal transition unit 235 is provided between the first stem 233 and the second stem 234. The circumferential width of the proximal transition unit 235 gradually increases from equal to the second stem 234 to equal to the first stem 233 in the proximal to distal direction, which may enhance the rigidity of the second stem 234 having a smaller circumferential width.

Similarly, the distal end of the inlet 12 is further provided with a distal connecting portion 22, and the distal connecting portion 22 includes a plurality of distal connecting legs 221 arranged at intervals in the circumferential direction, and the distal connecting legs 221 include a distal rod 222 connected to the inlet 12, and a second extending portion 226 connected to the distal rod 222. The distal rod 222 extends in the axial direction X, and the second extension 226 extends in the circumferential direction such that the second extension 226 is perpendicular to the distal rod 222.

The second extension 226 has a circumferential width greater than the circumferential width of at least a portion of the distal stem 222 such that the distal connecting leg 221 forms a generally "T" shaped structure for positioning engagement with the groove of the outer wall of the distal bearing chamber 207 to effect a secure connection of the bracket 20511 to the distal bearing chamber 207.

The distal rod 222 includes a third rod portion 223 connected to the inlet portion 12, and a fourth rod portion 224 connected at both ends to the third rod portion 223 and the second extension portion 226, respectively. The circumferential width of the fourth stem 224 is smaller than the circumferential width of the third stem 223 and also smaller than the circumferential width of the second extension 226. Thus, a constriction is also formed at the fourth stem 224, which can cooperate with a groove in the outer wall of the distal bearing chamber 207 to secure the distal connecting leg 221 to the distal bearing chamber 207.

A distal end transition unit 225 is provided between the third rod portion 223 and the fourth rod portion 224, and the circumferential width of the distal end transition unit 225 gradually decreases from equal to the third rod portion 223 to equal to the fourth rod portion 224 in the proximal-to-distal direction, so that the rigidity of the fourth rod portion 224 having a smaller circumferential width can be enhanced.

The distal connecting leg 221 and the proximal connecting leg 231 have the same or similar structural design, so that substantially the same technical effect can be achieved, and the detailed description is omitted.

The catheter pump of the embodiments of the present disclosure is used to achieve a partial pumping function of the heart. In a scenario suitable for left ventricular assist, a catheter pump pumps blood from the left ventricle into the main artery, providing support for blood circulation, reducing the workload of the subject's heart, or providing additional sustained pumping power support when the heart is not sufficiently pumping. Of course, the catheter pump may also be used to intervene as desired in other target locations of the subject, such as the right ventricle, blood vessels, or other organ interiors, depending on the interventional procedure.

Referring to fig. 3 and 4, a catheter pump 1000 of an embodiment of the present disclosure includes a power assembly 100 and a work assembly 200. The power assembly 100 includes a housing 101, a motor (not shown) housed within the housing 101, and a driving member (not shown) driven by the motor. As shown in connection with fig. 4, the working assembly 200 includes a catheter 201, a drive shaft 202 disposed through the catheter 201, a follower coupled to the proximal end of the drive shaft 202, and a drive catheter handle 204 and a pump head 205 coupled to the proximal and distal ends of the catheter 201, respectively. The pump head 205 may be delivered to a desired location of the heart, such as the left ventricle for pumping blood through the catheter 201, including a pump housing 2051 having a blood inlet 2051a and a blood outlet 2051b, and an impeller 2052 housed within the pump housing 2051. Blood inlet 2051a is located at a distal end of pump housing 2051 and blood outlet 2051b is located at a proximal end of pump housing 2051. A motor is provided at the proximal end of the catheter 201 and drives the impeller 2052 via the drive shaft 202 to spin the blood. An impeller 2052 is coupled to the distal end of the drive shaft 202. When the impeller 2052 rotates, blood may be drawn into the pump housing 2051 from the blood inlet 2051a and pumped out of the pump housing 2051 from the blood outlet 2051 b.

A pump housing 2051 is attached to the distal end of the catheter 201 and an impeller 2052 is attached to the distal end of the drive shaft 202. The pump housing 2051 includes a cover 20512 defining a blood flow path and a collapsible bracket 20511 supporting the deployed cover 20512, with the proximal end of the bracket 20511 being connected to the distal end of the catheter 201. The stent 20511 is any of the stent 20511 embodiments described above, wherein the proximal connector 23 of the stent 20511 is connected to the distal end of the catheter 201.

The coating 20512 has elasticity and covers a portion of the outside of the coating 20511, the impeller 2052 is housed in the coating 20511 and is positioned in the coating, the coating 20511 is supported at the distal end of the coating, a portion of the coating 20511 is positioned outside the distal end of the coating, and another portion of the coating 20511 is positioned in the coating. Wherein the impeller 2052 is mostly located within the main body portion 11 of the support 20511, with both ends (mainly hubs 20521) extending into the inlet portion 12 and the outlet portion 13.

The cover 20512 may cover the middle and rear end portions of the stent 20511, with the mesh 14 of the portion of the front end of the stent 20511 not covered by the cover 20512 forming a blood inlet 2051a. The rear end of the cover 20512 is wrapped around the distal end of the catheter 201, and the blood outlet 2051b is an opening formed in the rear end of the cover 20512.

The coating 20512 has a cylindrical section as a main body structure and a tapered section at a proximal end of the cylindrical section. The proximal end of the tapered section is disposed outside of the catheter 201 and secured to the outer wall of the catheter 201. The catheter 201 is connected to the proximal end of the support 20511 via a proximal bearing chamber 206 at its distal end, the proximal bearing chamber 206 having a proximal bearing 208 disposed therein for rotatably supporting the drive shaft 202.

Impeller 2052 includes a hub 20521 and blades 20522 supported on the outer wall of hub 20521. The blades 20522 are made of a flexible material, which in turn forms the collapsible pump head 205 with the support 20511 and the cover 20512 made of nickel, titanium memory alloy.

The distal end of the bracket 20511 is provided with a distal bearing chamber 207, and a distal bearing 209 for rotatably supporting the distal end of the drive shaft 202 is provided in the distal bearing chamber 207. The drive shaft 202 includes a flexible shaft 2021 that is inserted into the catheter 201 and a hard shaft 2022 that is connected to the distal end of the flexible shaft 2021 and is inserted into the hollow channel of the hub 20521, with the hub 20521 of the impeller 2052 being sleeved over the hard shaft 2022, and the proximal and distal ends of the hard shaft 2022 being inserted into the proximal and distal bearings 208 and 209, respectively. Thus, the hard shaft 2022 is supported at both ends by two bearings, coupled with the higher stiffness of the hard shaft 2022, provides a stiff support for the impeller 2052 within the pump casing 2051, allowing the impeller 2052 to be preferably retained within the pump casing 2051, maintaining a stable position of the impeller 2052 within the pump casing 2051.

The proximal bearing housing 206 may be an additional component connected between the distal end of the catheter 201 and the support 20511. Of course, the proximal bearing chamber 206 may also be part of the structure of the stent 20511, consisting of a proximal hypotube of the stent 20511.

The hard shaft 2022 is provided with a stop 211 proximal to the proximal bearing 208 for limiting distal movement of the hard shaft 2022 and impeller 2052 to prevent distal movement of the impeller 2052 due to reverse blood action when the impeller 2052 is rotated to pump blood. The shaft 2022 is further provided with a stop 212 proximal to the stop 211 for limiting proximal movement of the shaft 2022 and the stop 211 to prevent release of particulates by the stop 211 biasing the distal end of the catheter 201.

The distal end of the distal bearing chamber 207 is provided with a non-invasive support 210 made of a flexible material, and the non-invasive support 210 is supported on the inner wall of the ventricle in a non-invasive or non-invasive manner, separates the blood inlet 2051a of the pump head 205 from the inner wall of the ventricle, avoids the pump head 205 from attaching the blood inlet 2051a of the pump head 205 to the inner wall of the ventricle due to the reaction force of blood during operation, and ensures the effective pumping area.

The drive catheter handle 204 and the power assembly 100 may be removably coupled in a manner that may be a lock nut or a snap-fit connection as provided in US9421311B 2. The driven member is non-contact coupled with the driving member to transfer the rotational power of the motor to the drive shaft 202, thereby driving the impeller 2052 to rotate for pumping blood. As mentioned above, the driven member and the driving member may be magnetically coupled to each other as provided in CN103120810B or CN101820933B, or may be coupled to an eddy current coupler (Eddy Current Coupling) as provided in CN216061675U or CN114452527a, which is not limited in this embodiment.

The radially expanded state of the pump housing 2051 includes a natural expanded state and an operational expanded state when the impeller 2052 rotates, the natural expanded state and the operational expanded state being different states before and after the rotation of the impeller 2052. The support 20511 has a straight tube structure in a radially collapsed state and a spindle structure in a radially expanded state, and the axial length of the support 20511 in the radially collapsed state is greater than the axial length in the radially expanded state.

In the radially expanded state, the holder 20511 includes a substantially cylindrical main body portion 11 and substantially conical taper portions provided at both ends of the main body portion 11 in the axial direction X. The taper portion provided at the distal end of the main body portion 11 is an inlet portion 12, and the distal end of the inlet portion 12 is connected to a distal end connecting portion 22, and is connected to a distal end bearing chamber 207 via the distal end connecting portion 22. The tapered portion provided at the proximal end of the main body 11 is an outlet portion 13, and the proximal end of the outlet portion 13 is connected to a proximal connection portion 23, and is connected to a proximal bearing chamber 206 or a catheter 201 via the proximal connection portion 23.

The catheter pump 1000 is an external motor. Based on the above, the catheter pump 1000 may be configured with a built-in motor. At this point, the motor is coupled to the distal end of the catheter 201, and the elongate flexible drive shaft 202 is no longer threaded within the catheter 201, and the motor drives the impeller 2052 by way of a stiff shaft, magnetic coupling, or the like.

As shown in fig. 5, catheter pump 1000 further includes a delivery system including introducer 5 and interventional sheath 9. The introducer 5 has a pre-collapsed channel adapted to receive the pump head 205 therein in a radially expanded state to switch the pump head 205 to a radially collapsed state. The access sheath 9 has an access channel that may partially access the subject's vasculature through the puncture.

The introducer 5 is used to fold the pump head 205 from the radially expanded state to the radially collapsed state in vitro. Subsequently, the introducer 5 is docked with the interventional sheath 9 and the pump head 205 is transferred from the introducer 5 to the interventional sheath 9 by pushing the catheter 201 forward. Continuing to advance catheter 201, pump head 205 is moved out of the distal end of access sheath 9, expanding to a radially deployed state.

The catheter 201 is in a state of being inserted into the interventional sheath 9 during the pumping of blood by the pump head 205. When the pump blood is required to be removed, the pump head 205 moves backwards by pulling the catheter 201 backwards until the proximal end of the pump head 205 contacts the distal end of the intervention sheath 9, the catheter 201 is continuously pulled backwards, the pump head in the radial expansion state enters the intervention channel from the distal end of the intervention sheath 9, the pump head 205 is switched to the radial folding state, and then the pump head 205 can be removed after the pump head is continuously withdrawn.

For the working principle of the transport system, see the description of CN115227962 a. In addition, the operation of the introducer 5 for pre-folding the pump head in vitro can be referred to the scheme provided by CN217854163U, which is not described herein. The foregoing prior art is incorporated by reference herein for all purposes.

It has been demonstrated that the selective removal of the axial connecting rod 21 (Link) allows some of the proximal and distal apices 19, 18 to be left free, compared to stents that do not have a free state, and that the pump head 205 is prone to the problem of the membrane 20512 being pierced or punctured by either the proximal or distal apices 19, 18 when collapsed.

As can be seen from the foregoing, the direct cause of the membrane 20512 being pierced or punctured by the distal or proximal apices 18, 19 is due to the proximal or distal apices 19, 18 being left free. When the proximal 19 or distal 18 apices are relatively sharp, the risk of the covering film 20512 being pierced or punctured is higher. One means to solve this problem is to reduce the sharpness of the proximal and distal apices 19, 18 appropriately to make them more rounded or smooth.

Referring to fig. 2, distal vertex 18 and proximal vertex 19 in the null state have greater corner radii than distal vertex 18 and proximal vertex 19 not in the null state. Specifically, the corner radii of the distal and proximal apices 18, 19 in the unoccupied state are a plurality of times, such as 2 times, 3.5 times, 4 times, 5 times, etc., that of the corner radii of the distal and proximal apices 18, 19 in the unoccupied state.

Wherein only 2 distal vertices 18 and 2 proximal vertices 19 in the empty state are illustrated with larger fillet radii within the dashed box of fig. 2. It should be understood that reference is made to this illustration to the distal vertex 18 and the proximal vertex 19 being otherwise in the empty state.

All of the corner radii of the distal and proximal apices 18, 19 in the empty state are equal to maintain the balance of stent support.

By employing a large fillet radius design for the distal and proximal apices 18, 19 in the empty state, the exposed distal and proximal apices 18, 19 ends are blunted and no longer sharpened, greatly reducing the risk of the covering film 20512 being pierced.

In addition, it has been found that the indirect cause of the membrane 20512 being pierced or punctured by the distal tip 18 or the proximal tip 19 is due to the weaker stiffness of the sheath (including the interventional sheath 9 and introducer 5 described above) that folds the pump head 205. When the pump head 205 is folded, a strong reaction force is generated to the sheath tube which is folded. Once the sheath has insufficient wall thickness stiffness, it is difficult to withstand the puncture forces of the bare distal and proximal apices 18, 19, and the sheath can be pierced along with the covering film 20512. The opposite practice also demonstrates that when the sheath has a wall thickness that is sufficiently stiff to resist the penetration force of the exposed distal and proximal apices 18, 19, the covering film 20512 is also better protected from penetration.

Thus, the problem of puncture of the covering film 20512 can be solved by increasing the wall thickness rigidity of the sheath. One practical way to do this is to increase the wall thickness of the sheath.

The pump head 205 may be manually tampered with and assisted when pre-collapsed in vitro, for example by a physician pinching the stent with his or her hand to introduce it into the introducer 5. Thus, when the pump head 205 is pre-collapsed with the introducer 5, there is relatively little risk of the covering film 20512 being pierced.

In contrast, during withdrawal, the pump head 205 is collapsed by the access sheath 9, with the risk of the covering film 20512 being pierced being relatively great, mainly because the pump head 205 is still in the body at this time, and is no longer manually accessible and assisted, but can be collapsed by the radial force exerted by the access sheath 9 on the pump head 205. Then the stent 20511 reaction force is greater and the force exerted on the access sheath 9 by the distal tip 18 or proximal tip 19 to puncture or puncture is also greater.

Thus, the wall thickness of the access sheath 9 may be suitably increased, for example to a thickness of between 0.15 and 0.3mm, preferably between 0.2 and 0.25mm, defining the access channel. Practice has shown that increasing the wall thickness also greatly reduces the risk of the covering film 20512 being pierced.

Theoretically, the greater the wall thickness of the interventional sheath 9, the greater the wall thickness stiffness and the more pronounced the effect of preventing the covering film 20512 from being pierced. However, the larger the wall thickness of the insertion sheath 9, the larger the outer diameter of the insertion sheath 9, and the larger the corresponding puncture size, for the same inner diameter (reaching the desired folded size). The larger the size of the puncture, the more pain is given to the patient, and the higher the probability of causing complications, the more difficult the postoperative healing is.

Therefore, an upper limit needs to be set for the wall thickness increase of the interventional sheath 9. When the wall thickness is below 0.3mm, the external diameter of the interventional sheath 9 is not obviously increased, and the requirement of small interventional dimension is met.

The foregoing examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. A catheter pump comprising:

a catheter, a pump head through which blood can be pumped to a desired location of the heart;

The pump head includes: a pump housing having a blood inlet and a blood outlet, an impeller housed within the pump housing; the impeller is driven to rotate so as to suck blood into the pump shell from the blood inlet and pump the blood out from the blood outlet;

The pump housing includes a support operable to switch between a radially collapsed state and a radially expanded state; in a radially expanded state, the stent comprises a generally cylindrical main body portion, an inlet portion at an axially distal end of the main body portion, an outlet portion at an axially proximal end of the main body portion;

The main body part is provided with a plurality of meshes, each mesh comprises two oppositely arranged first edges and two oppositely arranged second edges, the first edges and the second edges at the same axial position are sequentially connected end to end along the circumferential direction to form a sawtooth ring, and the sawtooth ring is provided with a plurality of far-end vertexes and a plurality of near-end vertexes which are staggered along the circumferential direction;

The plurality of sawtooth rings are axially arranged, part of the sawtooth rings are axially aligned, adjacent distal vertexes are connected with the proximal vertexes so as to realize the fixed connection of the adjacent two sawtooth rings, and part of the sawtooth rings are axially aligned, and the adjacent distal vertexes and the adjacent proximal vertexes are in an unconnected empty state;

there are also at least two serration rings between the most proximal serration ring and the most distal serration ring, of which each adjacent two serration rings are axially aligned and all between adjacent distal and proximal apices are connected by an axial connecting rod.

2. The catheter pump of claim 1, wherein the distal and proximal apices in the empty state are axially spaced apart.

3. The catheter pump of claim 1, wherein the distal apices and proximal apices are partially axially aligned and adjacent are indirectly connected by an axial connecting rod.

4. The catheter pump of claim 1, wherein portions are axially aligned and adjacent distal and proximal apices are directly connected.

5. A catheter pump as claimed in claim 1 or 2, wherein, of the two axially most distal serrated rings, part of the axially aligned and adjacent distal and proximal apices are in a free state, the remainder of the axially aligned and adjacent distal and proximal apices being connected by an axial connecting rod.

6. Catheter pump according to claim 1 or 2, wherein in the two zigzag rings located axially most proximal, part of the axially aligned and adjacent distal and proximal apices are left free, the remaining axially aligned and adjacent distal and proximal apices are connected by an axial connecting rod.

7. The catheter pump of claim 6, wherein two of the zigzag rings at the axially distal-most end form a first mesh group and two of the zigzag rings at the axially proximal-most end form a second mesh group;

in the first mesh group or the second mesh group, there is at least one pair of axially aligned and adjacent distal and proximal apices between two circumferentially adjacent axial connecting rods, which are in a free state.

8. The catheter pump of claim 1, wherein the distal and proximal apices in the two most proximal serration rings are offset axially from the distal and proximal apices in the most distal two serration rings.

9. The catheter pump of claim 1, wherein the distal and proximal apices in the two most proximal serration rings are offset axially uniformly from the distal and proximal apices in the most distal two serration rings.

10. The catheter pump of claim 1, wherein the distal and proximal apices in the most proximal two sawtooth rings are at a null position, and the circumferential phase angles of the distal and proximal apices in the most distal two sawtooth rings are 180 °/m, where m is the number of proximal or distal null points.

11. The catheter pump of claim 1, wherein a gap is formed between the distal and proximal apices in the empty state, the gap connecting the circumferential mesh openings on both sides;

The main body portion includes a closed mesh having an opening area smaller than that of the meshes included in the inlet portion and the outlet portion, and both side meshes communicating with the gap have an opening area larger than that of the meshes included in the inlet portion and the outlet portion.

12. The catheter pump of claim 1, wherein the distal and proximal apices in the empty state have greater corner radii than the distal and proximal apices not in the empty state.

13. The catheter pump of claim 1, the pump housing further comprising a cover disposed outside the stent;

The pump head can be switched between a radial unfolding state and a radial folding state;

the catheter pump further includes an access sheath having an access channel and configured to be partially accessible through the puncture to the vasculature of the subject;

When the catheter is penetrated in the intervention sheath, the pump head in the radial unfolding state enters the intervention channel from the distal end of the intervention sheath by pulling the catheter backwards, so that the pump head is switched to the radial folding state;

Wherein,

The thickness of the wall defining the access channel is between 0.15 and 0.3 mm.