CN114588533B

CN114588533B - Foldable support and catheter pump thereof

Info

Publication number: CN114588533B
Application number: CN202210352238.5A
Authority: CN
Inventors: 付建新
Original assignee: Magassist Inc
Current assignee: Xinqing Medical Suzhou Co ltd
Priority date: 2022-04-03
Filing date: 2022-04-03
Publication date: 2023-05-30
Anticipated expiration: 2042-04-03
Also published as: CN114588533A

Abstract

A collapsible stent for facilitating collapsing and a catheter pump thereof are disclosed, the collapsible stent comprising a substantially cylindrical main body portion in a radially expanded state, an inlet portion and an outlet portion provided at both axial ends of the main body portion, respectively. The main body part is distributed with first mesh openings, the inlet part is distributed with second mesh openings, and the outlet part is distributed with third mesh openings. The mesh area of the first mesh is not smaller than the mesh area of the second mesh and/or the third mesh.

Description

Foldable support and catheter pump thereof

Technical Field

The present disclosure relates to the field of medical devices, in particular to an apparatus for heart assist use, more particularly to a collapsible stent and catheter pump thereof.

Background

Heart disease, represented by heart failure, is a major health problem leading to high mortality rates. While heart transplantation (Heart Transplantation, HT) is the best option for treating end-stage heart failure, the development and use of HT is hampered by the limited organ donor. Ventricular assist, in particular left ventricular assist devices (Left Ventricular Assist Device, LVAD), have demonstrated its value in heart failure patients who are not fit for HT. Thus, in the face of such patients, there is an urgent need to clinically support the treatment of heart failure using mechanical ventricular assist devices, and to rapidly and minimally invasively deploy therapeutic regimens.

A traditional mechanical device for treating the above-mentioned diseases is an intra-aortic balloon pump (IABP), which is placed in the aorta and actuated in an anti-pulse manner to provide partial support to the circulatory system. However, IABP is capable of providing very small flows (typically 0.5L/min). Therefore, in practice, the IABP is difficult to independently play or take on the ventricular assist function, and in many cases, only plays a role in regulating flow and pressure. For this reason, minimally invasive rotary catheter pumps have been developed in which the pump head can be inserted into the ventricle, which can provide higher flow rates.

The pump head of the catheter pump comprises a pump shell and an impeller arranged in the pump shell, wherein the pump shell comprises a bracket and a coating film covered outside the bracket. The support is a grid structure and comprises a middle part which is approximately cylindrical, an inlet part and an outlet part which are approximately conical and are positioned at two ends of the middle part. Wherein the impeller is located substantially in the middle portion, which is therefore also commonly referred to as the pump portion.

The stent disclosed in the prior art, represented by CN102805885B, finds that the foldable stent has the problems of large folding force and difficult folding when the sheath tube is folded during the interventional procedure, and the problem may and very probably will cause structural damage of the pump shell and disconnection of the stent and the catheter.

In addition, the negative or bad technical effects of the above structure include difficulty in achieving a desired size of the pump head after folding.

Disclosure of Invention

The inventor has found that the main reason for the problems is the design of the stent grid. In particular, the mesh openings of the inlet and outlet portions of the disclosed stent are larger than the mesh openings of the intermediate portion. Thus, the support part corresponding to the impeller is provided with higher strength.

The reason for this is: in the process of rotating the impeller to drive blood to flow, the blood can exert a radial outward fluid back pressure on the stent and the tectorial membrane, thereby leading to the stent and the tectorial membrane having radial expansion trend. This tendency to expand can lead to instability of the pump gap and thus to poor hydraulics.

For the reasons, the existing bracket adopts the design of dense middle grids and sparse two ends grids, and is beneficial to maintaining the strength of the impeller part and further stabilizing the pump clearance and the hydraulic effect.

This design of the existing stent, while having the benefits described above, also provides negative or undesirable technical effects. In particular, the stent is designed with the mesh opening size according to the above characteristics, the strength of the intermediate pump portion is high, which is advantageous in terms of stabilization of the pump gap and the hydrodynamic effect, but disadvantageous in terms of the folding compliance. The folding of the middle pump part with high strength can bring about the problems of high folding force and difficult folding, and the problems can possibly and very probably cause structural damage of the pump shell and disconnection of the connection between the bracket and the catheter.

And, the mesh of the intermediate pump portion is dense, corresponding to a larger volume of the stent. In the case of a defined axial length after collapsing of the stent, the thickness, i.e. the radial dimension, is large, which results in a difficulty in achieving the desired pump head dimensions after collapsing.

Based on the above study, the present disclosure solves the above problems by adopting the following technical scheme:

the foldable stand comprises a substantially cylindrical main body portion in a radially expanded state, an inlet portion and an outlet portion provided at axial ends of the main body portion, respectively. The main body portion is provided with first meshes, the inlet portion is provided with second meshes, and the outlet portion is provided with third meshes. The mesh area of the first mesh is greater than or equal to the mesh area of the second and/or third mesh.

The catheter pump includes: a drive shaft disposed through the catheter and having a proximal end drivingly connected to an output shaft of the motor, and a pump head that can be delivered through the catheter to a desired location of the heart for pumping blood. The pump head includes: a pump casing, and an impeller accommodated in the pump casing. The pump housing comprises a support for housing the impeller as described in the above embodiments, a cover defining a blood flow path. The pump housing is connected to the distal end of the catheter and the impeller is connected to the distal end of the drive shaft.

The present disclosure provides a foldable stand having a main body portion with a first mesh size distributed larger than the mesh of an inlet portion or an outlet portion. The main body of the support adopts a large grid design, so that the solid volume of the support is conveniently reduced, the solid volume of the support in the sheath tube is ensured to be as small as possible when the support is folded to the sheath tube, and the size (intervention size) after folding is reduced, so that the size of the pump head after folding is expected to be more easily achieved. In addition, the design of the big meshes is beneficial to properly reducing the strength of the main body part for resisting folding, thereby being more convenient for folding.

Drawings

FIG. 1 is a schematic illustration of a catheter pump provided in one embodiment of the present disclosure;

FIG. 2 is a front view of the pump head of FIG. 1;

FIG. 3 is a cross-sectional view of FIG. 2;

FIG. 4 is a partial cross-sectional view of the pump head of FIG. 1;

FIG. 5 is a perspective view of the foldable stand structure of FIG. 1;

fig. 6 is a front view of fig. 5.

Detailed Description

The terms "proximal", "distal" and "anterior", "posterior" are used in this disclosure with respect to a clinician manipulating an interventional catheter pump. 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 proximal and posterior and the intervening intracorporeal portion is distal and anterior.

The catheter pump of the embodiment of the disclosure is used for assisting in heart failure and realizing partial blood 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. 1 to 6, a catheter pump of an embodiment of the present disclosure includes a power assembly 3 and a working assembly. The power assembly 3 includes a housing and a motor having an output shaft and accommodated in the housing, and the working assembly includes a guide tube 2, a drive shaft 30 penetrating the guide tube 2, and a pump head 1. The pump head 1 can be delivered to a desired location of the heart, such as the left ventricle for pumping blood, through the catheter 2, and includes a pump housing having a blood inlet 106 and a blood outlet 105, and an impeller 10 housed within the pump housing. The motor is provided at the proximal end of the catheter 2, is connected to the catheter 2 via the coupler 4, and drives the impeller 10 to rotate to pump blood via the drive shaft 30.

The pump housing is connected to the distal end of the catheter and the impeller 10 is connected to the distal end of the drive shaft 30. The pump housing comprises at least a covering membrane 5 defining a blood flow path and a foldable support 6 supporting the unfolded covering membrane 5, the proximal end of the support 6 being connected to the distal end of the catheter 2. As shown in fig. 4 and 6, the proximal end of the stent 6 is provided with a connecting secondary tube 43. The connecting sub-pipe 43 is provided with a connecting hole 430 constituting a female buckle, thereby forming a mechanical connection structure of a snap-fit type with the catheter 2.

As shown in fig. 2 and 3, the cover 5 is covered on the outside of a part of the foldable bracket 6, and the bracket 6 is partially provided inside the cover 5 and partially provided outside the cover 5. The impeller 10 is accommodated in the holder 6 and is positioned in the coating 5, the holder 6 is supported at the distal end of the coating 5, part of the holder 6 is positioned at the outer side of the distal end of the coating 5, and the other part of the holder 6 is positioned in the coating 5.

The coating 5 has a cylindrical section as a main structure and a tapered section located at the proximal end of the cylindrical section. The proximal end of the conical section is sleeved outside the catheter 2 and fixed with the outer wall of the catheter 2. The catheter 2 is connected to the proximal end of the stent 6 by a proximal bearing housing at its distal end, in which a proximal bearing is provided for rotatably supporting the drive shaft 30.

The distal end of the bracket 6 is provided with a distal bearing chamber 7, and a distal bearing for rotatably supporting the distal end of the drive shaft 30 is provided in the distal bearing chamber 7. The bracket 6 maintains the spacing of the proximal and distal bearing chambers 7, thereby providing stable rotational support for the drive shaft 30. The drive shaft 30 comprises a flexible shaft penetrating the catheter 2 and a hard shaft connected to the distal end of the flexible shaft, the hub of the impeller 10 being sleeved on the hard shaft, the proximal and distal ends of the hard shaft penetrating in the proximal and distal bearings, respectively. By means of the hard shaft and the bearings at both ends, a stable strength support is provided for the impeller 10 in the pump casing, keeping the position of the impeller 10 stable in the pump casing.

The coupler 4 is connected to the proximal end of the catheter 2, and a fluid flow path is provided between the catheter 2 and the drive shaft 30, through which perfusion fluid is introduced to lubricate the rotation of the drive shaft 30 and avoid frictional heat generation. The coupler 4 is provided with a perfusate input interface communicated with the liquid flow channel, and the perfusate input interface is communicated with the liquid flow channel. The distal end of the coupler 4 is provided with a retaining sleeve for the catheter 2 to pass through, which sleeve can act as a fixation for the catheter 2.

The far end of the far end bearing chamber 7 is connected with a noninvasive support piece 8, the noninvasive support piece 8 is of a flexible pipe body structure and is characterized in that the end part of the noninvasive support piece 8 is a flexible bulge in an arc shape or a winding shape, so that the noninvasive support piece 8 is supported on the inner wall of a ventricle in a noninvasive or nondestructive mode, the blood inlet 106 of the pump head 1 is separated from the inner wall of the ventricle, the suction inlet of the pump head 1 is prevented from being attached to the inner wall of the ventricle due to the reaction force of blood in the working process of the pump head 1, and the effective area of pumping is ensured.

The pump housing comprises a radially collapsed state adapted to be inserted into or transported within the subject's vasculature, corresponding to a natural deployed state when the impeller 10 is not rotated. By arranging the foldable pump shell, the pump shell has smaller folding size and larger unfolding size, so that the requirements of relieving pain of a subject and easy intervention in the intervention/transportation process and providing large flow are met.

The pump head 1 has an interposed configuration and an operating configuration. In the corresponding insertion configuration of the pump head 1, the pump housing and the impeller 10 are in a radially collapsed state, so that the pump head 1 is inserted into or transported in the vasculature of the subject at a first outer diameter dimension. In the corresponding operating configuration of the pump head 1, the pump housing and the impeller 10 are in a radially expanded state, so that the pump head 1 pumps blood at a desired location with a second outer diameter dimension that is larger than the first outer diameter dimension.

Accordingly, the radially expanded state of the pump casing includes a natural expanded state in which the impeller 10 is stationary and an operational expanded state in which the impeller 10 is rotated. The support 6 is wholly in a straight tube structure (intervention configuration) in a radial folding state and wholly in a spindle structure (working configuration) in a natural unfolding state. The stent 6 has a first axial length in the radially collapsed state and a second axial length in the naturally expanded state, wherein the first axial length is greater than the second axial length. Wherein the extent of the change in length of the stent 6 is greater than the strain of the transition 53.

The support 6 is an integrally formed structure made of memory alloy material, more specifically, a hot-press integrally formed structure. The polygonal mesh, especially diamond mesh design of the bracket 6 can realize better folding and unfolding by means of the memory property of nickel-titanium alloy. In the radially expanded state, the holder 6 includes a substantially cylindrical main body portion 40, and substantially conical taper portions (41, 42) provided at both axial ends of the main body portion 40. The cone portions (41, 42) provided at the distal end of the main body portion 40 are inlet portions 41, and the distal end of the inlet portions 41 is further provided with a front connecting portion 44, and the distal bearing housing 7 is connected by the front connecting portion 44. The cone portions (41, 42) provided at the proximal end of the main body portion 40 are outlet portions 42, and the proximal end of the outlet portions 42 is provided with a connecting sub-tube through which the catheter 2 is connected by the connecting sub-tube 43.

In the natural expanded state, the axial length of the main body portion 40 is 5.2mm to 12mm, the outer diameter of the main body is 6.5mm to 8.5mm, the axial length of the cone portions (41, 42) is 3.5mm to 7.5mm, more specifically, the axial length of the cone portions (41, 42) is 4mm to 7mm, and the taper is 10 degrees to 50 degrees.

Further, for ease of folding, a transition 53 is provided between the cone portions (41, 42) and the body portion 40. Wherein, when the bracket 6 is switched from the radial folding state to the natural unfolding state, the strain of the transition part 53 is larger than that of the main body part 40, and the strain of the transition part 53 is larger than that of the cone parts (41, 42).

The cone sections (41, 42) are provided with: a distally located generally conical inlet portion 41, and a proximally located generally conical outlet portion 42. There is a proximal transition between the body portion 40 and the outlet portion 42, and a distal transition between the body portion 40 and the inlet portion 41. The proximal and distal transitions are located substantially symmetrically at the axial ends of the body portion 40. The axial length (projected length on the central axis) or the extension length (length extending from one axial end to the other end) of the transition 53 is much smaller than the axial length or the extension length of the main body portion 40, the inlet portion 41 or the outlet portion 42, wherein the axial length of the main body portion 40 is substantially the same as the extension length.

The main body portion 40 is provided with first mesh openings 50, the inlet portion 41 is provided with second mesh openings 51, and the outlet portion 42 is provided with third mesh openings 52. The first, second and

third mesh openings

50, 51, 52 are closed polygonal holes to form a stable support structure, stabilizing the pump gap. The first mesh 50 and the second mesh 51, the third mesh 52 are equal in number. Further, the first mesh 50, the second mesh 51 and the third mesh 52 are at least two polygonal holes with unequal side lengths, and the polygonal holes can be irregular polygonal holes or polygonal holes with mirror symmetry structures, which is not limited in this application.

The body portion 40 is of a large mesh design, with less mesh density and better collapse compliance than the inlet portion 41 and outlet portion 42 of the body portion 40. Specifically, the mesh area of the first mesh 50 is greater than or equal to the mesh area of the second mesh 51, and the mesh area of the first mesh 50 is greater than or equal to the mesh area of the third mesh 52. At this time, the first mesh 50 is the largest area mesh of the stent, and is distributed on the main body portion 40.

Of course, in other embodiments, the first mesh 50 may be greater than or equal to the mesh area of at least one of the second mesh 51 and the third mesh 52. For example, the first mesh 50 is larger than or equal to the mesh area of the second mesh 51, but smaller than the mesh area of the third mesh 52.

Further, the mesh perimeter of the first mesh 50 is larger than the mesh perimeter of the second mesh 51 and/or the third mesh 52. Preferably, the mesh perimeter of the first mesh 50 is not only larger than the mesh perimeter of the second mesh 51, but also larger than the mesh perimeter of the third mesh 52. Wherein the perimeter of the mesh is the total length of the edges surrounding the mesh or the total length of the hole edges of the mesh.

The first, second and

third mesh openings

50, 51, 52 may be partially located on one of the body portion 40, the

inlet portion

41, 42 and partially located on the other of the body portion 40, the

inlet portion

41, 42, except that a majority of the first mesh openings 50 are located on the body portion 40, a majority of the second mesh openings 51 are located on the inlet portion 41, and a majority of the third mesh openings 52 are located on the outlet portion 42. Specifically, more than 80% of the mesh area of the first mesh 50 is located on the main body portion 40, and further, the first mesh 50 is entirely located on the main body portion 40. More than 60% of the mesh area of the second mesh 51 is located at the inlet portion 41, and more than 60% of the mesh area of the third mesh 52 is located at the outlet portion 42.

Further, 71% or more of the mesh area of the second mesh 51 is located at the inlet portion 41, and 71% or more of the mesh area of the third mesh 52 is located at the outlet portion 42. Further, more than 75% of the mesh area of the second mesh openings 51 is located at the inlet portion 41, and more than 75% of the mesh area of the third mesh openings 52 is located at the outlet portion 42.

The main body portion 40, the inlet portion 41, the outlet portion 42 do not exclude the additional provision of other meshes, and the first mesh 50, the second mesh 51, the third mesh 52 are the main meshes of the main body portion 40, the inlet portion 41, the outlet portion 42, respectively. Specifically, the first mesh 50 is located at a side area of the main body portion 40 where the total area of the main body portion 40 occupies 78% or more, the second mesh 51 is located at a side area of the inlet portion 41 where the total area of the inlet portion 41 occupies 72% or more, and the third mesh 52 is located at a side area of the outlet portion 42 where the total area of the outlet portion 42 occupies 72% or more. Further, the first mesh 50 is located at a side area of the main body portion 40 where the total area of the main body portion 40 occupies 82% or more, the second mesh 51 is located at a side area of the inlet portion 41 where the total area of the inlet portion 41 occupies 84% or more, and the third mesh 52 is located at a side area of the outlet portion 42 where the total area of the outlet portion 42 occupies 84% or more.

The side area of the main body 40 is the surface area of the cylindrical surface of the main body 40, and the side areas of the inlet 41 and outlet 42 are the tapered surface areas of the corresponding cones. The proportion of the area is calculated as the area of the mesh at the position of the main body 40, the inlet 41 and the outlet 42, and the area of the mesh at the other position does not participate in calculation. For example, the second mesh openings 51 include a first portion of the main body portion 40 having a triangular shape and a second portion of the main body portion 40 having an elongated triangular shape, wherein the first portion is located at the main body portion 40 and the second portion is located at the inlet portion 41, and accordingly, the total area of the plurality of second mesh openings 51 located at the inlet portion 41 is the total area of mesh openings of all the second portions, and the proportion of the side area with respect to the inlet portion 41 is calculated as the total area of mesh openings of the second portions.

In the present embodiment, the maximum axial length L1 of the first mesh 50 is greater than the maximum circumferential length L2 of the first mesh 50. Specifically, the maximum axial length L1 of the first mesh 50 is 5 to 10mm, more preferably 6 to 9mm, still more preferably 7.34 to 8.96mm. The maximum circumferential length L2 of the first mesh 50 is 2 to 3.5mm, more preferably 2.21 to 3.21mm, still more preferably 2.75 to 3.0mm.

It should be noted that, the maximum axial length L1 and the maximum circumferential length L2 are obtained by measuring different positions of the foldable stand 6 in a naturally unfolded state, and are not obtained by comparing in different states. As shown in fig. 6 for example, the maximum axial length L1 of the first mesh 50 is the spacing between two axially opposite apices 505, and the maximum axial length L1 is the spacing between two circumferentially opposite apices 504.

The maximum axial length L1 of the first mesh 50 is 0.4 times or more the axial length of the main body portion 40, more preferably 0.5 times or more the axial length of the main body portion 40, and still more preferably 0.8 times or more the axial length of the main body portion 40.

The body portion 40 has edges that are contoured to form a first mesh 50. To ensure that the body portion 40 has sufficient strength against fluid back pressure in the operational deployment state to stably maintain the pump gap, the radial thickness Lh of the edges of the first mesh 50 is 0.12 to 0.34mm, further, the radial thickness Lh is 0.16 to 0.24mm, still further, the radial thickness Lh is 0.187 to 0.221mm. The circumferential width Lk of the edge is 0.1 to 0.4mm, further, the circumferential width Lk is 0.13 to 0.28mm, and still further, the circumferential width Lk is 0.157 to 0.254mm. By the design, the problem of support strength reduction caused by the design of the big meshes can be avoided, and the support 6 can meet the strength requirement of the catheter pump for stabilizing the blood pumping and the requirement of folding compliance.

To facilitate smooth folding and avoid stress concentration, a transition radius is provided between adjacent edges of the first mesh 50, the radius of curvature of the transition radius being 0.05-0.5 mm. That is, each vertex position of the first mesh 50 is provided with a smooth transition structure having a radius of curvature of 0.05 to 0.5mm.

The first mesh 50 may be quadrangular holes such as diamond holes or hexagonal holes. For example, the first mesh 50 may be a diamond-shaped mesh having a major axial dimension, the diamond-shaped first mesh 50 having two axial first peaks 505 forming front and

rear peaks

510a and 510b of a saw-tooth configuration for the first and

second edges

501 and 502, respectively. The two second peaks 504 are disposed opposite to each other in the circumferential direction, and the first and

second edges

501 and 502 form left and right tooth tops of a saw-tooth structure, respectively.

The first mesh 50 is a mirror-symmetrical structure mesh. As shown in fig. 5 and 6, the first mesh 50 is a hexagonal hole of mirror symmetry. Specifically, the first mesh 50 has two main edges 503 arranged in parallel in the circumferential direction, and the main edges 503 extend in the axial direction F1. Where major edge 503 is the longest edge (also referred to as an edge) of first mesh 50, the axial length of major edge 503 is greater than 0.5 times the axial length of first mesh 50. The length of the main edge 503 is 0.5 times or more the length of the first edge 501.

The axial dimension of first mesh 50 is increased by major edge 503 such that the axial dimension of first mesh 50 is the major dimension. And when the sheath tube is taken in, the sheath tube can be smoothly folded along the axial direction F1, and the resistance during folding is reduced. Further, the length of second edge 502 is equal to the length of first edge 501, and the length of main edge 503 is greater than the length of second edge 502. The major edge 503 is the longest edge of the first mesh 50, providing the largest side length of the mesh.

The first mesh 50 further comprises two first edges 501 in parallel and two second edges 502 in parallel. A major edge 503 is connected between a first edge 501 and a second edge 502, the first edge 501, the second edge 502, and the major edge 503 enclosing a closed hexagonal first mesh 50. The axial length of the first mesh 50 is substantially equal to the radial projected length thereof on the axis. The second vertex 504 is located at least one end of the second edge 502 and the first vertex 505 is located at least one end of the first edge 501. The first edge 501 and the second edge 502 have the same length and are arranged in a mirror symmetry manner. The first edge 501 and the second edge 502 are the longest edges of the first mesh 50, and have substantially the same strain, and are symmetrically designed.

As described above, the folding is facilitated by providing the major edges 503 with a length direction parallel to the axial direction, so that the major length direction of the first mesh 50 is the axial direction F1. Specifically, the length of the main edge 503 is 3 to 5mm, more preferably 3.26 to 4.87mm, and still more preferably 3.861 to 4.532mm. The length of major edge 503 is greater than the length of first edge 501. The length of the first edge 501 is 0.4 times or more the length of the main edge 503, and further 0.5 times or more the length of the main edge 503.

The radial thickness and circumferential width of the first edge 501, the second edge 502, and the main edge 503 may be different or equal, and may be within the above range. In this embodiment, the radial thickness of the first edge 501, the second edge 502, and the main edge 503 is equal, and the circumferential widths of the first edge 501, the second edge 502, and the main edge 503 are also equal.

It is noted that any numerical value in this disclosure includes all values of the lower value and the upper value that increment by one unit from the lower value to the upper value, and that there is at least two units of space between any lower value and any higher value.

For example, the length of major edge 503 is illustrated as 3-5 mm, further 3.26-4.87 mm, and still further 3.861-4.532 mm, for purposes of illustration as not explicitly recited above such as 3.901mm, 3.951mm, 4.125mm, 4.235mm, 4.452mm, 4.576mm, 4.531mm, etc.

As mentioned above, the exemplary ranges given above in 0.1 interval units do not exclude increases in interval in appropriate units, e.g., in numerical units of 0.01, 0.02, 0.03, 0.04, 0.05, etc. These are merely examples that are intended to be explicitly recited in this description, and all possible combinations of values recited between the lowest value and the highest value are believed to be explicitly stated in the description in a similar manner.

Unless otherwise indicated, all ranges include endpoints and all numbers between endpoints. "about" or "approximately" as used with a range is applicable to both endpoints of the range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30," including at least the indicated endpoints.

Other descriptions of the numerical ranges presented herein are not repeated with reference to the above description.

The two axial end points of the main edge 503 respectively form a second vertex 504, the rear axial end point of the main edge 503 is shared with a first edge 501, the shared end point forms a second vertex 504, the front axial end point of the main edge 503 is shared with a second edge 502, and the shared end point forms another second vertex 504. The circumferential spacing of the two major edges 503 is the spacing of the circumferentially opposite second vertices 504. The common end point of the first edge 501 and the second edge 502 forms a first vertex 505. The first vertex 505 is provided with a first rounded structure (transition rounded as described above) and the second vertex 504 is provided with a second rounded structure (transition rounded as described above). By providing a transition rounded structure to provide a smooth transition between the edges of the first mesh openings 50, a stable support structure is constructed.

At least one of the first edge 501, the second edge 502, and the main edge 503 is a straight edge, the multiple edges of the mesh form a polygonal mesh, and the whole edge is a straight line, which may be a straight line without bending as shown in fig. 4 and 5. Alternatively, the edges may be straight edges that allow some slight curvature and still be intuitively considered as polygons.

In embodiments of the present disclosure, the edges of the polygonal mesh may be of generally rectilinear configuration.

As shown in fig. 6, the plurality of first mesh holes 50 are sequentially arranged in the circumferential direction to form a support hole ring, and the body portion may be distributed with one or more support hole rings in the axial direction F1. In this embodiment, the main body portion is provided with only one support eyelet, i.e. the main body portion is provided with a single ring of support eyelets. Considering that the first mesh 50 has a large mesh area, its axial dimension is also large, and thus, there is no need to provide an excessive number of support rings. Based on this design, the body portion 40 of the present disclosure may be provided with one or two support orifice rings. In embodiments of two or more support hole rings, adjacent two support hole ring portions are staggered.

The first edges 501 and the second edges 502 are alternately arranged along the circumferential direction to form sawtooth rings 520 with sawtooth structures, and two axially adjacent sawtooth rings 520 are opposite to form a supporting hole ring. Considering the number of support rings in this embodiment, the number of zigzag rings 520 is 2-3 to facilitate the formation of one or two support rings.

The serration rings 520 have front tooth tips 510a toward the inlet portion 41 and rear tooth tips 510b toward the outlet portion 42, the plurality of serration rings 520 are circumferentially arranged, and the front tooth tips 510a of one serration ring 520 are disposed opposite to the rear tooth tips 510b of the other serration ring 520 in the axial direction F1 in adjacent two serration rings 520 and are connected by a main edge.

The front tooth top 510a of one sawtooth ring 520 is connected (e.g., integrally formed or welded, etc.) with the rear tooth top 510b of the other sawtooth ring 520 along the axial direction F1 by a main edge 503 parallel to the axial direction, so as to form a hexagonal first mesh 50. Accordingly, each support ring includes a plurality of hexagonal first mesh openings 50 arranged in a circumferential direction.

In other embodiments, the first mesh may not have a main edge, and the front tooth top 510a of one sawtooth ring 520 and the rear tooth top 510b of the other sawtooth ring 520 are directly connected along the axial direction F1 to form a diamond-shaped first mesh. Correspondingly, each supporting hole ring comprises a plurality of diamond-shaped first meshes which are distributed along the circumferential direction.

In this embodiment, the inlet portion 41 is located on the front side of the main body portion 40, at the distal end of the foldable stand 6. The second mesh 51 is a closed mesh provided at the inlet portion 41. The second mesh 51 has an extension length of 4 to 12mm, and a maximum circumferential length of 2 to 3.5mm, more preferably 2.21 to 3.21mm, still more preferably 2.75 to 3.0mm. Similar to the second mesh openings 51, the third mesh openings 52 have a maximum circumferential length of 2 to 3.5mm, more preferably 2.21 to 3.21mm, still more preferably 2.75 to 3.0mm.

The proximal end of the second mesh 51 extends onto the main body portion 40 and the distal end of the third mesh 52 extends onto the main body portion 40. The extension length of the second mesh hole 51 mainly includes the length thereof extending on the tapered surface of the inlet portion 41 and the partial length thereof extending on the main body portion 40, and is not the radial projection length in the axial direction. The third mesh 52 is similar thereto.

Specifically, the second mesh 51 includes a first portion 51a located at the main body portion and a second portion 51b located at the inlet portion. Since the first portion 51a is located on the main body portion, the first portion 51a extends substantially the same length as the axial length thereof. The maximum circumferential length L2 of the second mesh holes 51 is equal to the maximum circumferential length L2 of the first mesh holes 50. Wherein the area of the second portion 51b is larger than the area of the first portion 51a, and the extension length of the second portion 51b is larger than the extension length of the first portion 51 a. Specifically, the extension length of the second portion 51b is 2 times or more the extension length of the first portion 51 a.

In the desired expanded state, the inlet portion 41 and the outlet portion 42 are substantially mirror-symmetrical, and the first mesh 50 and the second mesh 51 are substantially mirror-symmetrical. In contrast, the fourth mesh 54 is a non-closed cell, the fifth mesh 55 is a closed cell, and the description of the similar structures for both may be referred to by reference to each other, and the present disclosure will not be specifically described here.

The distal end of the second mesh 51 does not extend beyond the inlet portion 41 and the proximal end of the third mesh 52 does not extend beyond the outlet portion 42. That is, the second mesh 51 does not extend to the front connection part 44, and the third mesh 52 does not extend to the connection sub-pipe 43. The proximal end of the fourth mesh 54 is axially spaced from the main body portion 40 by more than 1/5 of the axial length of the inlet portion 41 and the distal end of the fifth mesh 55 is axially spaced from the main body portion 40 by more than 1/5 of the axial length of the outlet portion 42.

The plurality of second mesh holes 51 are circumferentially arranged in a circle, and similarly, the plurality of third mesh holes 52 are circumferentially arranged in a circle. Further, the inlet portion 41 is also provided with fourth mesh openings 54, the fourth mesh openings 54 extending distally to the distal end face of the holder 6, thereby forming circumferentially distributed connecting legs 440 at the front connecting portion 44 for facilitating connection of the distal bearing chamber 7.

The outlet portion 42 is provided with a fifth mesh 55 having a smaller mesh area than the third mesh 52. The fifth mesh 55 is a closed mesh that extends to the transition between the connecting sub-pipe 43 and the outlet portion 42, avoiding affecting the structural strength of the connecting sub-pipe 43. Further, the mesh area of the fifth mesh 55 is smaller than 0.5 times the mesh area of the third mesh 52.

In view of the above, the first edge 501 and the second edge 502 have a common end point (front tooth top 510a or rear tooth top 510 b). The plurality of common end points (front tooth top 510a or rear tooth top 510 b) are circumferentially arranged, and the stretching ribs 518/528 extend from the common end points to the cone portions (inlet portions, outlet portions), and the stretching ribs 518/528 extend to the front end of the bracket or the rear end of the bracket and diverge at the cone portions to form two sub-ribs 5181, 5182. One of the sub-ribs 5181 of one of the tensile ribs merges with an extension of one of the sub-ribs 5182 of an adjacent tensile rib to form a connecting leg 440. The number of connecting legs 440 is equal to the number of (front) stretch ribs 518.

The inlet portion 41 is provided at an end remote from the main body portion 40 with a front connecting portion 44, the front connecting portion 44 including a plurality of connecting legs 440 dispersed in a circumferential direction, the connecting legs 440 having a T-shaped configuration. The distal end of the connection leg 440 has a leg end 45 with a circumferential dimension larger than that of the leg body, the connection leg 440 can be clamped into a clamping groove on the outer wall of the distal bearing chamber 7, the distal end of the clamping groove is communicated with an annular groove, the leg body of the connection leg 440 is clamped into the clamping groove, the leg end 45 of the connection leg 440 is clamped into the annular groove, and the dispersed plurality of connection legs 440 are fixed on the distal bearing chamber through an outer hoop.

The inlet portion 41 includes a plurality of forward stretching ribs 518 extending from the forward tip 510a toward the forward connecting portion 44, the distal end of each forward stretching rib 518 branching into two sub-ribs extending forward at the inlet portion 41, and a fourth mesh opening is formed between the two sub-ribs. A sub-rib of one of the front-stretch ribs 518 (front-stretch rib a) merges with a sub-rib extension of an adjacent front-stretch rib 518 (front-stretch rib b) to form a connecting leg 440.

The outlet portion 42 is located at the proximal end of the collapsible bracket 6, and is provided with a connecting sub-tube 43 at the proximal end thereof, the connecting sub-tube 43 being arranged around the outer wall of the catheter, and being fixed to the catheter or the proximal bearing chamber by means of heat-melting or gluing, whereby the proximal fixation of the collapsible bracket 6 is achieved. The connecting sub-tube 43 is provided with a clamping hole 430 for buckling and buckling the outer wall of the catheter or the proximal bearing chamber.

The outlet portion 42 includes a plurality of rear tensile ribs 528 extending from the rear tooth top 510b toward the connecting secondary tube 43, the proximal end of each rear tensile rib 528 extending rearwardly and bifurcating to form two sub-ribs, with a fifth mesh opening formed therebetween. The fifth mesh extends to connect the secondary pipe 43 to stop forming a closed mesh. One sub-rib of one of the rear tensile ribs 528 (rear tensile rib c) merges with one sub-rib extension of the adjacent rear tensile rib 528 (rear tensile rib d) to terminate in the connecting sub-tube 43.

The foregoing is merely a few embodiments of the present invention and those skilled in the art, based on the disclosure herein, may make numerous changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the invention.

Claims

1. A collapsible stent for a catheter pump for assisting pumping of blood for heart failure, operable to switch between a radially collapsed state and a radially expanded state; in a radially expanded state, the holder includes a substantially cylindrical main body portion, an inlet portion and an outlet portion provided at both axial ends of the main body portion; the main body part is distributed with a plurality of first meshes, the inlet part is distributed with a plurality of second meshes, and the outlet part is distributed with a plurality of third meshes; the mesh area of the first mesh is larger than the mesh area of the second and/or third mesh; the first meshes are sequentially distributed along the circumferential direction to form a supporting hole ring; the main body part is provided with only one supporting hole ring;

a total area of the plurality of first mesh openings accounting for 78% or more of the main body portion side area; the total area of the plurality of second mesh openings accounts for 72% or more of the side area of the inlet portion; the total area of the plurality of third mesh openings occupies 72% or more of the side area of the outlet portion.

2. The foldable stand of claim 1, the first, second, third mesh being closed mesh; the mesh perimeter of the first mesh is greater than the mesh perimeter of the second and/or third mesh.

3. The foldable stand of claim 1, wherein more than 80% of the first mesh area is located in the main body portion, more than 60% of the second mesh area is located in the inlet portion, and more than 60% of the third mesh area is located in the outlet portion.

4. A foldable stand as claimed in claim 3, wherein the first mesh is located entirely within the main body portion.

5. The foldable stand of claim 1, the first mesh having a maximum axial length that is greater than 0.4 times the axial length of the main body portion.

6. The foldable stand of claim 5, the first mesh having a maximum axial length that is greater than 0.5 times the axial length of the main body portion.

7. The foldable stand of claim 5, the first mesh having a maximum axial length that is greater than 0.8 times the axial length of the main body portion.

8. The foldable stand of claim 1, wherein the first mesh has a maximum axial length of 5-10 mm.

9. The foldable stand of claim 8, the first mesh having a maximum axial length of 6-9 mm.

10. The foldable stand of claim 8, the first mesh having a maximum axial length of 7.34-8.96 mm.

11. The foldable stand of claim 1, wherein the first mesh has a maximum circumferential length of 2-3.5 mm.

12. The foldable stand of claim 11, wherein the first mesh has a maximum circumferential length of 2.21-3.21 mm.

13. The foldable stand of claim 11, wherein the first mesh has a maximum circumferential length of 2.75-3.0 mm.

14. The foldable stand of claim 1, the body portion having edges that are contoured to form a first mesh; the radial thickness of the edge is 0.12-0.34 mm.

15. The foldable stand of claim 14, wherein the radial thickness of the rim is between 0.16 mm and 0.24mm.

16. The foldable stand of claim 14, wherein the radial thickness of the edge is between 0.187 and 0.221mm; the circumferential width of the edge is 0.1-0.4 mm.

17. The foldable stand of claim 16, wherein the circumferential width of the edge is between 0.13 mm and 0.28mm.

18. The foldable stand of claim 16, wherein the circumferential width of the rim is between 0.157 mm and 0.254mm.

19. The foldable stand of claim 1, the axial length of the first mesh being greater than the circumferential length of the first mesh; the first mesh is provided with main edges which are arranged in parallel along the circumferential direction, and the main edges extend along the axial direction; the axial length of the major edge is greater than 0.5 times the maximum axial length of the first mesh.

20. The foldable stand of claim 19, the first mesh further comprising two first edges in parallel, two second edges in parallel, the first and second edges being equal in length and less than the length of the main edge, wherein the first edge has a length that is greater than 0.4 times the length of the main edge.

21. The foldable stand of claim 20, wherein the first edge has a length that is greater than 0.5 times the length of the main edge.

22. The foldable stand of claim 19, wherein the major edges have a length of 3-5 mm.

23. The foldable stand of claim 19, wherein the major edge has a length of 3.26-4.87 mm.

24. The foldable stand of claim 19, wherein the major edges have a length of 3.861-4.532 mm.

25. The foldable stand of claim 20, wherein a transition radius is provided between adjacent edges of the first mesh, the transition radius having a radius of curvature of 0.05-0.5 mm.

26. A foldable stand as claimed in claim 3, the second mesh including a first portion at the main body portion and a second portion at the inlet portion; the second portion extends a length greater than an axial length of the first portion.

27. The foldable stand of claim 1, the distal end of the second mesh does not extend beyond the inlet portion; the proximal end of the third mesh does not extend beyond the outlet portion.

28. The foldable stand of claim 1, the inlet portion further provided with a fourth mesh extending distally up to a distal end face of the stand; the axial spacing between the proximal end of the fourth mesh and the body portion is greater than 1/5 times the axial length of the inlet portion.

29. The foldable stand of claim 1, the outlet portion further having a fifth mesh with a smaller mesh area than the third mesh, the fifth mesh being a closed mesh.

30. The foldable stand of claim 29, the fifth mesh having a mesh area that is less than 0.5 times the mesh area of the third mesh.

31. The foldable stand of claim 29, the axial spacing between the distal end of the fifth mesh and the main body portion being greater than 1/5 times the axial length of the outlet portion.

32. The foldable stand of claim 20, wherein the first and second edges are alternately arranged in a circumferential direction to form a zigzag ring having a zigzag structure; the serrated ring having a front tooth tip towards the inlet portion and a rear tooth tip towards the outlet portion; the main body part is provided with two or three sawtooth rings in an axial direction.

33. The foldable stand of claim 32, said inlet portion including a plurality of forward stretching ribs extending from a forward tooth top of a serrated ring to a forward end of said stand; one end of each front stretching rib far away from the main body part extends forwards at the inlet part to form two sub ribs; a fourth mesh is arranged between the two sub-ribs of each front stretching rib.

34. The foldable stand of claim 33, the outlet portion including a plurality of rear tensile ribs extending from a rear tooth top of another serrated ring toward a rear end of the stand; one end of each rear stretching rib far away from the main body part extends backwards at the outlet part to form two sub ribs; a fifth mesh is arranged between the two sub-ribs of each rear stretching rib.

35. A catheter pump comprising:

a motor;

a conduit;

the driving shaft is arranged in the guide pipe in a penetrating way, and the proximal end of the driving shaft is in transmission connection with the output shaft of the motor;

a pump head, which pumps blood through the catheter to a desired location of the heart, comprising: a pump casing, an impeller accommodated in the pump casing; the pump housing comprising a support as defined in any one of claims 1 to 34 for housing an impeller, a cover defining a blood flow path; the covering film covers part of the outside of the bracket; the stent is connected to the distal end of the catheter, and the impeller is connected to the distal end of the drive shaft.