CN115770352A

CN115770352A - Intervention type catheter pump and pump body thereof

Info

Publication number: CN115770352A
Application number: CN202111046167.8A
Authority: CN
Inventors: 付建新; 张家良
Original assignee: Magassist Inc
Current assignee: Magassist Inc
Priority date: 2021-09-07
Filing date: 2021-09-07
Publication date: 2023-03-10

Abstract

Disclosed are an intervention type catheter pump capable of stably maintaining a pump gap and a pump body thereof, the pump body comprising: a pump housing having a blood inlet and a blood outlet, an impeller housed in the pump housing and configured to provide power to a flow of blood; the pump housing includes at least a membrane defining a blood flow channel; the pump body comprises a radial folding state and a radial unfolding state, and can be switched between the radial folding state and the radial unfolding state in an operation mode; the cover film is configured not to undergo tensile deformation in a radially expanded state of the pump casing, as compared to an unstressed state.

Description

Intervention type catheter pump and pump body thereof

Technical Field

The invention relates to the field of medical equipment, in particular to equipment for assisting the heart, and more particularly relates to an interventional catheter pump and a pump body thereof.

Background

An interventional catheter pump device (blood pump for short) can pump blood. Taking left ventricle assistance as an example, in the prior art, a pump of an interventional catheter pump device is generally disposed in a left ventricle of a subject, an impeller of the pump is driven to rotate by a flexible shaft, and the flexible shaft is driven by a motor to transmit power to the pump.

To ensure stable contraction and expansion, existing catheter pumps are capable of being inserted into a patient's blood vessel and expanded after insertion. During compression and expansion, the rotor (e.g., impeller) and the housing are often deformed accordingly, which presents problems: it is desirable to maintain the pump clearance, i.e., the spacing gap between the radially outer end of the impeller and the inner wall of the casing, at a minimum and constant level in order to optimize the pump performance.

Disclosure of Invention

In view of the above-mentioned disadvantages, it is an object of the present invention to provide an interventional catheter pump and a power transmission assembly therefor, which can stably maintain a pump gap.

In order to achieve the purpose, the invention adopts the following technical scheme:

a pump body for an interventional catheter pump capable of being delivered to a desired location of a heart to pump blood; the method comprises the following steps: a pump housing having a blood inlet and a blood outlet, an impeller housed in the pump housing and serving to provide power to the flow of blood; the pump housing includes at least a membrane defining a blood flow channel. The pump body comprises a radial folding state and a radial unfolding state, and can be switched between the radial folding state and the radial unfolding state in an operation mode. The cover film is configured not to undergo tensile deformation in a radially expanded state of the pump casing, as compared to an unstressed state.

A pump body for an interventional catheter pump capable of being delivered to a desired location of a heart to pump blood; the method comprises the following steps: a pump housing having a blood inlet and a blood outlet, an impeller housed in the pump housing and serving to provide power to the flow of blood; the pump housing includes at least a membrane defining a blood flow channel. Wherein the pump body comprises a radially collapsed state adapted for delivery in the vasculature of a subject, a naturally expanded state when the corresponding impeller is not rotating, and an operative state when the corresponding impeller is rotating. During the switching of the pump body from the naturally deployed state to the operating state, the blood backpressure exerted on the membrane caused by the rotation of the impeller causes the folds of the membrane to be at least partially flattened.

Preferably, flattening of the pleats increases the diameter of the film.

Preferably, the flattening of the pleats is such that the increase in diameter of the film does not exceed 3%.

Preferably, during the process from the natural deployment state to the working state, there is at least a sub-process of the covering membrane without diameter increase.

Preferably, the membrane is configured to not undergo tensile deformation when the pump casing is in a naturally deployed or operating state, as compared to an unstressed state.

Preferably, the pump casing further includes a support member for supporting the deployed coating film; the radially deployed state comprises a natural deployed state when the corresponding impeller does not rotate; the membrane is configured such that a critical point stress causing tensile deformation thereof is equal to or greater than a force applied thereto by the support member when the pump casing is in a naturally expanded state.

Preferably, the radially deployed state also comprises an operating state when the corresponding impeller is rotating; the stress of the critical point of the film stretching deformation is larger than or equal to the force applied to the film by the blood backpressure caused by the rotation of the impeller when the pump body is in the maximum working condition.

Preferably, the material strength of the film itself is sufficient to resist the outward expansion tension of the support member, and the circumferential tensile deformation amount of the film when the pump casing is switched from the radially collapsed state to the naturally expanded state is 0.

Preferably, the material strength of the film itself is sufficient to resist the force applied thereto by the back pressure of blood due to the rotation of the impeller, and the amount of circumferential tensile deformation of the film when the pump casing is switched from the naturally expanded state to the operating state is 0.

Preferably, the diameter of the film in the operating condition of the pump body is greater than the diameter of the film in the natural deployment condition of the pump body.

Preferably, the pump body comprises a working state corresponding to the rotation of the impeller; in the operating state of the pump body, the rotation of the impeller induces a blood backpressure exerted on the membrane such that the folds of the membrane are at least partially flattened.

A pump body for an interventional catheter pump capable of being delivered to a desired location of a heart to pump blood; the method comprises the following steps: a pump housing having a blood inlet and a blood outlet, an impeller housed in the pump housing and serving to provide power to the flow of blood; the pump housing includes at least a membrane defining a blood flow channel. The pump body includes a radially collapsed state adapted for delivery within the subject's vasculature, a naturally expanded state when the corresponding impeller is not rotating, and an operative state when the corresponding impeller is rotating. The diameter of the film in the working state of the pump body is larger than that of the film in the natural unfolding state of the pump body.

Preferably, the pump casing further includes a support member for supporting the deployed coating film; in the pump casing in the naturally expanded state, the support member is radially restrained by the film without being completely expanded.

Preferably, the pump casing further includes a support member for supporting the deployed coating film; in the naturally expanded state of the pump casing, the support member has a contact support portion that contacts the film. At least a part of the contact support portion is spaced from the film in an operating state of the pump case.

Preferably, the cover membrane comprises a cylindrical section, a proximal conical section provided at a proximal end of the cylindrical section. The blood inlet extends to the cylinder section at the proximal conical section, part of the blood outlet is positioned at the proximal conical section, and the other part of the blood outlet is positioned at the cylinder section. The blood inlet port, at least part of the axial length, tapers in circumferential width as it extends proximally from its distal end. Alternatively, the length of the portion of the blood outlet in the proximal conical section is greater than the length of the portion in the cylindrical section.

Preferably, the material of tectorial membrane is TPU or PTFE or PEBAX.

An interventional catheter pump comprising: the pump comprises a catheter, a driving shaft arranged in the catheter in a penetrating mode, a power assembly connected with the near end of the driving shaft and a pump body in any one embodiment; the impeller of the pump body is connected with the far end of the driving shaft.

According to the catheter pump and the pump body thereof provided by the embodiment of the invention, the film does not generate tensile deformation in a radial expansion state, and has strong deformation resistance. And further, the shape of the supporting component can be stably restrained and maintained in a radial expansion state, and the pump gap is kept, so that the pump body keeps better pump efficiency.

Drawings

FIG. 1 is a schematic diagram of an interventional catheter pump configuration provided by one embodiment of the present invention;

FIG. 2 is an enlarged view of portion A of FIG. 1;

FIG. 3 is a perspective view of FIG. 2;

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

FIG. 5 is a perspective view of the cover of FIG. 1;

FIG. 6 is a front view of FIG. 5;

FIG. 7 is a schematic diagram of a pump body of an interventional catheter pump provided in accordance with another embodiment of the present invention;

FIG. 8 is a graph of the change in diameter under fluid back pressure for 6 different sets of pumps of the present invention.

Description of reference numerals: 1. a pump body; 2. a conduit; 3. a power assembly; 4. a coupling body; 5. an impeller; 6. an impeller shaft; 7. a proximal bearing chamber; 8. a flexible support; 10. a pump housing; 11. coating a film; 12. a support member; 13. a blood inlet; 14. a blood outlet; 15. a distal bearing chamber; 16. connecting a loop; 17. covering the film near end; 18. coating the distal end of the membrane; 19. a connecting strip; 20. a front blood outlet part; 21. a posterior blood outlet; 50. a blade; 51. a hub; 121. a tapered stent proximal end; 123. a tapered stent distal end; 122. a cylindrical stent section; 125. sleeving a ring; 110. a cylinder section; 111. a proximal conical section.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without making creative efforts based on the embodiments in the present invention, shall fall within the protection scope of the present invention.

It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a single embodiment.

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

The terms "proximal", "distal" and "anterior", "posterior" are used herein with respect to a clinician operating an interventional catheter pump. The terms "proximal" and "posterior" refer to portions that are relatively close to the clinician, and the terms "distal" and "anterior" refer to portions that are relatively far from the clinician. For example, the extracorporeal portion is proximal and posterior, and the interventional intracorporeal portion is distal and anterior.

Referring to fig. 1 to 6, an interventional catheter pump according to an embodiment of the present invention includes: pump body 1, pipe 2, power component 3. The power component 3 is arranged at the near end of the guide pipe 2, is connected with the guide pipe 2 through the coupling body 4, and is connected with the pump body 1 through a flexible shaft arranged in the guide pipe 2 in a penetrating way.

The pump body 1 can be delivered to a desired position of the heart to pump blood, and the power source of the pump body 1 can be an external motor or an internal motor, and the invention is not particularly limited. In the external embodiment of power supply, the pump body 1 can be connected with an external motor through a conduit 2, and the conduit 2 accommodates a flexible shaft and transmits power to an impeller 5 of the pump body 1.

In the embodiment with a built-in power source, the built-in motor can be a hydraulic motor or an electric motor (such as an electric motor), and the power assembly 3 can be conveyed into the body by means of the conduit 2 and can be kept close to the pump body 1, so that the length of the connecting shaft between the two is reduced, and the problems of friction heating and the like caused by the rotation of the long shaft are reduced.

The pump body 1 includes a pump housing 10 having a blood inlet 13 and a blood outlet 14, and an impeller 5 housed in the pump housing 10. The impeller 5 is used to power the flow of blood, and the pump housing 10 includes at least a film 11 defining a blood flow passage.

The pump body 1 comprises a radially collapsed state and a radially expanded state. Wherein the pump housing 10 is operable to be switched between a radially collapsed state and a radially expanded state. Compared with the unstressed state, the film 11 does not generate tensile deformation when the pump casing is in a radial expansion state.

The pump casing 10 further includes a support member 12 for supporting the deployed film 11. The support member 12 may be integrally provided in the coating film 11, or may be provided separately from the coating film 11 to support the coating film 11.

In the radially expanded state of the pump casing 10, the support member 12 is expanded in the radial direction in contact with the inner wall of the coating film 11 to support and expand the coating film 11. In the unstressed state, the film 11 is not subjected to tensile deformation in comparison with the radially expanded state in which the film 11 is not subjected to a force in the pump casing 10.

The radially expanded state in which the pump casing 10 is not subjected to a force is a naturally expanded state in which the impeller 5 does not rotate.

The radially expanded state includes a natural expanded state corresponding to when the impeller 5 is not rotated. The critical point stress at which the film 11 undergoes tensile deformation is equal to or greater than the force applied to it by the support member 12 when the pump casing is in the naturally expanded state. In this way, when only the support member 12 applies the radial support expanding force to the film 11, the film 11 does not reach the stretching deformation limit force, and further, the film 11 is not stretched in the naturally expanded state supported by the support member 12.

The radially expanded state also includes an operating state corresponding to the rotation of the impeller 5. In order to ensure the toughness of the coating film 11, a more stable pump gap is provided, the pump efficiency is stabilized, and the stress of the critical point of tensile deformation of the coating film 11 is greater than or equal to the force applied to the coating film 11 by the blood backpressure caused by the rotation of the impeller 5 when the pump body 1 is in the maximum working condition.

The maximum operating condition of the pump body 1 corresponds to the maximum rotational speed of the impeller 5 at nominal power. At this time, the pump flow rate corresponds to the maximum value, and the blood back pressure is also at the maximum value. In this embodiment, the maximum value of the blood back pressure still does not exceed the stress of the critical point of the film 11 where the tensile deformation occurs, and further, in the working state of the rotation of the impeller, the film 11 still does not generate the tensile deformation, so as to avoid the change of the pump gap and stabilize the pump efficiency.

It should be understood that the tensile deformation of the film 11 in the present invention means that the film 11 is deformed in length in the circumferential direction. When subjected to a radial force, it is reflected in an increase in circumferential length (circumference). However, when the film 11 itself has wrinkles, the wrinkles are flattened by the expansion action of the support member 12, and the stretching of the film 11 is not included.

The wrinkles of the coating 11 are generated in many cases by folding, and the coating 11 is forcibly compressed and folded by the radial restraining action of the folded sheath, and the wrinkles are generated. This, of course, does not exclude wrinkles in the cover film 11 caused by other factors. For example, wrinkles may be in the form of e.g. creases, (micro) wrinkles, which may be formed during manufacture, or may be deformed by themselves during placement, or may be formed during testing, etc.

The pump body 1 has an intervention configuration as well as an operating configuration. In the respective access configuration of the pump body 1, the pump housing 10 and the impeller 5 are radially collapsed, so that the pump body 1 can be accessed and/or transported in the vascular system of a subject with a first, smaller outer diameter dimension. In the corresponding operating configuration of the pump body 1, the pump casing 10 and the impeller 5 are in a radially expanded condition, so that the pump body 1 pumps blood at a desired location (for example the left ventricle) with a second outer diameter dimension greater than the first outer diameter dimension.

As shown in fig. 4, the impeller 5 includes a hub 51 connected to the distal end of the drive shaft and blades 50 supported on the outer wall of the hub 51. The blade 50 may be a helical blade so as to drive the flow of blood by rotation.

In the corresponding intervening configuration of the pump body 1, the vanes 50 are wrapped around the outer wall of the hub 51 and at least partially contact the inner wall of the pump casing 10. In the corresponding operating configuration of the pump body 1, the vanes 50 extend radially outward from the hub 51 and are spaced from the inner wall of the pump casing 10, so as to avoid the pump casing 10 from affecting the rotation of the vanes 50 and to avoid the rotation of the vanes 50 from damaging the pump casing 10.

In the catheter pump of the present embodiment, in use, the pump body 1 and a part of the catheter 2 (specifically, the front end portion of the catheter 2) are fed into and held in the subject, and the size of the pump body 1 and the part of the catheter 2 needs to be as small as possible. Therefore, the axial projected area of the pump body 1 and a portion of the duct 2 is smaller than the axial projected area of other components of the power assembly 3 (e.g., motor) including the pump body 1.

Thus, the smaller size of the pump body 1 and a portion of the catheter 2 can be maintained in the subject during delivery to reduce subject pain and complications due to the oversized intervention. Other parts of the power assembly 3 may have relatively large dimensions to meet the structural design requirements.

The catheter pump may be used to displace blood from the heart, pump blood from the left ventricle into the aorta, provide support for blood circulation, reduce the workload on the subject's heart, or provide additional continuous pump body 1 hemodynamic support when the heart pump body 1 is not fully capable of blood flow. Of course, the catheter pump may also be placed as desired into a target site of the body, such as a blood vessel, or other organ, for pumping blood or body fluids, by invasive surgery.

In the present embodiment, the material strength of the film 11 itself is sufficient to resist the outward expansion tension of the support member, and the amount of circumferential tensile deformation of the film 11 when the pump casing 10 is switched from the radially collapsed state to the naturally expanded state is 0, and no circumferential tensile deformation occurs.

Further, the material strength of the film 11 itself is sufficient to resist the force applied thereto by the back pressure of blood due to the rotation of the impeller 5, and the amount of circumferential tensile deformation of the film 11 when the pump casing is switched from the naturally expanded state to the operating state is 0.

The material of the coating 11 is TPU (thermoplastic polyurethane elastomer rubber), PEBAX (polyethylene terephthalate elastomer) or PTFE (polytetrafluoroethylene). Preferably, the film 11 is made of a block polyether amide resin material such as PEBAX. The film 11 has no loss of mechanical properties under repeated deformation and is fatigue resistant, possessing good resilience and elastic recovery properties and precise dimensional stability. Further, the pump gap is stably maintained without tensile deformation under the support of the support member 12.

The cover 11 is made of a material that can withstand the radial expansion force of the support member 12, and does not undergo tensile deformation when the pump casing 10 is in a naturally expanded state, and the tensile deformation is circumferential tensile deformation.

It will be appreciated that the inner diameter or cross-sectional area of the membrane 11 is the same in the unstressed condition as compared to the naturally deployed condition and does not change. The coating film 11 assumes a cylindrical structure in an unstressed state of the pump casing 10 without being supported by the support member 12. It is also understood that the natural spread state of the film 11 is not subjected to tensile deformation, and the amount of tensile deformation is 0, compared to the state in which the supported member 12 is spread from the inside to the outside.

The unstressed condition in the radially expanded state (natural expanded state) is compared with the condition in which the impeller 5 rotationally drives the fluid (operating state). When the impeller 5 rotates and drives the blood to flow, the blood generates a certain radial expansion force (fluid back pressure) on the film 11.

In the radially expanded state in which the pump casing 10 is not subjected to force, that is, in the case where the expansion force is applied to the coating 11 only by the support member 12, the coating 11 does not undergo tensile deformation and has a good deformation resistance. Further, the shape is better maintained during the blood pumping process, the pump gap is maintained, and the pump efficiency is maintained.

Further, the coating 11 does not generate tensile deformation in the radial expansion state, and the coating 11 has strong deformation resistance. In this way, the shape of the support member 12 can be stably restrained and maintained in the radially expanded state, the pump gap is maintained, and the pump body 1 is kept at a preferable pump efficiency.

Bearing in mind the above description, the pump body 1 comprises a radially collapsed condition suitable for delivery in the vascular system of a subject, a natural expanded condition when the corresponding impeller 5 is not rotating and an operative condition when the corresponding impeller 5 is rotating. During the switching of the pump body 1 from the naturally deployed state to the operating state, the blood backpressure exerted on the membrane 11, induced by the rotation of the impeller 5, causes the folds of the membrane 11 to be at least partially flattened.

The flattening of the pleats increases the diameter of the film 11, and the flattening of the pleats increases the diameter of the film 11 by no more than 3%, further no more than 2%, or even no more than 1%.

The diameter increase rate is a rate of change in diameter of the coating film 11 in a naturally expanded state of the pump casing 10 as compared with an operating state, and is determined by the number of folds and the degree of undulation of the coating film 11, and further by the flexibility of the material of the coating film 11.

Specifically, the flexibility of the material of the coating 11 largely determines the number of wrinkles and the degree of undulation. That is, the lower the flexibility of the material of the coating film 11, the greater the number of wrinkles and the greater the degree of undulation of the coating film 11, and the closer to 3% the increase rate of the diameter of the coating film 11 is to be achieved when the wrinkles are flattened. On the other hand, the more flexible the material of the coating film 11, the smaller the number of wrinkles of the coating film 11 and the smaller the undulation degree, and the larger the rate of increase in the diameter of the coating film 11 deviates from 3% when the wrinkles are flattened.

Therefore, in some scenarios that cannot be clearly excluded, the contribution of the flattening of the wrinkles to the rate of increase in the diameter of the coating 11 may be close to 0 in the case where the coating 11 is selected from a material that conforms to the characteristics of being particularly soft and thus has few wrinkles.

The cover 11 is of an integrally formed construction, and the distal end 19 of the cover 11 has a distal opening that is circular and is flared by the support member 12 to form, with the support member 12, the blood inlet 13 of the pump housing 10. The distal end 19 of the cover film 11 is further provided with a connecting strip 19, and the distal end of the connecting strip 19 is fixedly connected to the distal bearing chamber 15.

When the covering membrane 11 is in a radial expansion state, the connecting strip 19 is approximately in a stretched state, the near end and the far end of the covering membrane 11 are fixed through the connecting strip 19 and the connecting ring sleeve 16 of the far end 18 of the covering membrane 11, and then the covering membrane 11 is in an overall straight state in the axial direction, so that a continuous and stable rotary blood pumping space is provided for the rotation of the impeller 5.

Of course, in other embodiments, the distal end 19 of the cover 11 may be fixedly attached to the support member 12. For example, the inner wall of the distal end 19 of the cover membrane 11 is bonded to the outer wall of the support member 12, and contracts and expands with the support member 12.

In the pump case 10 in the naturally expanded state, the support member 12 has a contact support portion that contacts the film 11. In particular, support member 12 includes a tapered stent proximal end 121, a tapered stent distal end 123, and a cylindrical stent segment 122 located between tapered stent proximal end 121 and tapered stent distal end 123. Wherein at least part of the axial length of the cylindrical carrier section 122 constitutes a contact support.

The covering film 11 is sleeved outside the cylindrical stent section 122 and is supported by the cylindrical stent section 122 in a contact manner to construct the pump casing 10 in a stable cylindrical shape. The distal end 19 (end face) of the cover 11 does not extend beyond the cylindrical stent section 122.

The radially expanded state of the pump casing 10 forms an operative configuration. In the operating configuration, there are a state in which the impeller 5 rotationally drives the blood flow (operating state) and a state in which the impeller 5 is stationary (natural deployment state). The state of the blood (static state and flow) differs, and a force acts on the cover film 11 differently. Further, when the impeller 5 rotates and drives the blood to flow, not only the supporting force of the support member 12 against the film 11 but also the radial pushing (fluid back pressure) of the blood against the film 11 by the driving of the impeller 5 may occur.

Therefore, in an operating state in which the impeller 5 is at a high rotation speed (thousands of revolutions per minute or more) as compared to the film 11 in a non-operating state (naturally unfolded state), the film 11 is stretched to some extent in the circumferential direction of the film 11 due to the flattening of the wrinkles, but the film 11 itself is not subjected to tensile deformation in the circumferential direction.

The diameter of the film 11 in the working state of the pump body 1 is larger than that in the natural unfolding state of the pump body. The diameter of the film 11 is a first diameter when the pump body 1 is in a naturally unfolded state. The diameter of the film 11 is the second diameter when the pump body is in the working state. Wherein the second diameter is greater than the first diameter.

This diameter is the diameter of the inner cavity enclosed by the cover film 11. Under the working state, due to the existence of fluid back pressure, at least part of folds of the coating film 11 are flattened, so that the cross-sectional shape of the internal cavity of the enclosure tends to be more circular, the inner wall of the coating film 11 tends to be smoother, and the diameter of the coating film 11 (the diameter of the enclosure cavity) is increased.

Specifically, in the operating state of the pump casing 10, the blood back pressure exerted on the film 11 caused by the rotation of the impeller 5 causes the wrinkles of the film 11 to be at least partially flattened. During the switching of the pump body 1 from the naturally deployed state to the operating state, the backpressure of the blood exerted on the membrane 11, induced by the rotation of the impeller 5, causes the flattening of the folds of the membrane 11, at least in part, which results in a rate of increase of the diameter of the membrane 11 of not more than 3%.

The rate of increase in diameter is seen in the diameter variation of the 6 sets of coating films 11 in fig. 8 (where 1# -a to 3# -C represent different coating film names) at different back pressures. Wherein two pressure end points and one diameter of the film 11 at substantially intermediate pressure are shown in each graph. As can be seen from each graph, the coating film 11 is elongated to some extent in the circumferential direction with an increase in back pressure, but the increase in diameter is all within 0.1 mm.

It should be noted that, in the process of shifting the pump casing 10 from the naturally deployed state to the operating state, at least a sub-process in which the diameter of the coating film 11 does not increase exists. As the back pressure increases during the test, the diameter of the coating 11 sometimes remains constant or even decreases with a range of pressures.

The reason why there is a process in which the diameter does not increase is that the film 11 assumes a cross-sectional shape that is circular-like but not strictly circular in a naturally expanded state due to the presence of wrinkles. The corrugations comprise radially inward depressions and possibly also radially outward bulges. If the selected diameter measuring points are two convex points, the initially measured diameter is larger, and after the wrinkles are flattened, the convex points are flattened, thereby causing a phenomenon that the diameter is reduced although the back pressure is increased.

Of course, this also further or indirectly demonstrates that the circumferential elongation of the cover film 11 in the present invention is due to flattening of the wrinkles and not to tensile deformation. Because the stretching deformation can lead to the continuous increase of the diameter without the phenomena of invariance and reduction.

In one embodiment, at least a portion of the contact support (cylindrical shelf section 122) of the pump casing 10 is spaced from the cover 11 in a state where the impeller 5 rotationally drives the blood flow. Under the action of fluid backpressure, part of wrinkles of the coating 11 are further flattened, the inner diameter is increased to be separated from the contact supporting part, and under the action of the toughness of the coating 11, the condition that tensile deformation is not generated is limited, the wrinkles are further flattened to enable the coating 11 to stretch in the circumferential direction, but the change of the elongation is smaller than 3%, the change of the circumferential elongation is small, the interval gap between the impeller 5 and the coating 11 can be maintained under the working state, and the continuous stability of the pump effect is maintained.

During the transition of the pump housing 10 from the radially collapsed state to the radially expanded state, relative movement is permitted between the contact support and the cover 11, and the location at which the cover 11 makes contact with the contact support, such as the cylindrical stent section 122, is permitted to change. The relative position of the support member 12 and the coating film 11 is fixed without change.

The contact support part and the film 11 are only in contact support without fixed connection, and therefore a certain degree of relative movement is formed between the contact support part and the film 11 during the unfolding process of the film 11, so that the expected unfolding of each other is realized. And the contact support part provides circumferential support force for the tectorial membrane 11 without providing radial and circumferential relative movement constraints, and allows the tectorial membrane 11 to generate radial or circumferential relative movement relative to the contact support part, so that the contact part of the tectorial membrane 11 with the contact support part or the stent is changed in the unfolding process.

As shown in fig. 5 and 6, the coating film 11 includes a cylindrical section 110 and a proximal tapered section 111 provided at the proximal end of the cylindrical section 110. The axial length of cylindrical section 110 is greater than the length of proximal conical section 111. The blood inlet 13 extends to the cylindrical section 110 at the proximal conical section 111, and the length of the cylindrical section 110 of the cover film 11 is greater than the length of the proximal conical section 111.

The proximal end of the proximal conical section 111 is provided with a connection collar 16, the connection collar 16 being fixedly connected to the outer wall of the catheter 2, whereby a fixed connection of the distal end 18 of the covering membrane 11 is achieved. The connection ring 16 may be fixedly connected to the catheter 2 by means of adhesion, or heat fusion, or crimping. The connection position of the covering membrane 11 to the catheter 2 or the connection collar 16 is located on the proximal side of the proximal bearing chamber 7.

Wherein part of the blood outlet 21 is located in the proximal conical section 111 and the other part of the blood outlet 20 is located in the cylindrical section 110. The plurality of blood outlets 14 are arranged in the circumferential direction. The partial blood outlets 20 are located in the cylindrical section 110, so that the discharged blood is centrifugally discharged at this position, and the outflow of the plurality of blood outlets 14 stabilizes the position of the pump body 1, and thus stabilizes the blood outflow. The partial blood outlet 21 is located at the proximal conical section 111, so that the outputted blood forms an axial flow, and the partial blood outlet 14 of the cylindrical section 110 ensures the flow rate of the blood outlet 14 to avoid the loss of the flow direction.

To maintain the structural strength of the forward end of the cover 11 and to maintain the stability of the shape structure, the blood inlet 13, which is at least partially axially long, gradually decreases in circumferential width as it extends proximally from its distal end.

In the present embodiment, as shown in fig. 5 and 6, the circumferential width of the part of the blood outlet 21 located in the proximal tapered section 111 gradually decreases as it extends from the distal end to the proximal end, and the circumferential width of the other part of the blood outlet 20 located in the cylindrical section 110 gradually increases as it extends from the distal end to the proximal end.

In one embodiment, as shown in fig. 7, the blood outlet 14 tapers in circumferential width in a direction extending from the distal end to the proximal end.

A part of the blood outlet 14 located in the proximal conical section 111 is used as a rear blood outlet 21, and another part of the blood outlet 14 located in the cylindrical section 110 is used as a front blood outlet 20. Wherein the length of the part of the blood outlet 14 proximal to the conical section 111 is larger than the length of the part thereof proximal to the cylindrical section 110. That is, the length of the rear blood outlet portion 21 is greater than the length of the front blood outlet portion 20.

The circumferential width of the front blood outlet portion 20, at least a portion of the (axial) length, is greater than or equal to the maximum circumferential width of the rear blood outlet portion 21. In any two axial portions of the blood outlet 14 in the rear blood outlet portion 21, the circumferential width of the portion located downstream is smaller than or equal to the circumferential width of the portion located upstream. The proximal end of the blood outlet 14 has a circumferential width smaller than the circumferential width of the distal end thereof.

In the present embodiment, the supporting member 12 or the single stent is an integrally formed structure, the supporting member 12 and the covering membrane 11 are separate structures, and at least a part of the supporting member 12 is located inside the covering membrane 11 and contacts the inner wall of the supporting covering membrane 11.

In the pump casing 10 in an unstressed radially expanded state, the support member 12 is radially constrained by the coating film 11 without being completely expanded. The supporting member 12 is made of memory alloy, and after the constraint of the sheath tube is lost, the supporting member 12 recovers to the shape to support the coating 11 until the coating 11 is constrained and can not be supported. At this time, the support member 12 provides a radially outward supporting force to the coating film 11, and the coating film 11 resists deformation of the support member 12 by its own toughness without tensile deformation, maintaining the stability of the shape.

It should be noted that the support member 12 of the present invention is not limited to a single stent in the cover 11, and may include a plurality of stents distributed at different positions in the axial direction to support different portions of the cover 11. For example, there may be a stent supporting the proximal end 17 of the cover 11 to stably support the blood outlet 14, thereby maintaining the stability of the shape of the blood outlet 14 and reducing the influence on the blood flow.

In the present embodiment, the support member 12 is a stent with a lattice structure, and the design of multiple meshes, especially diamond-shaped meshes, on the collapsible stent facilitates the collapsing and unfolding of the support member 12. The impeller 5 is housed in the support member 12 and is positioned in the coating film 11.

The support member 12 is supported at the distal end 18 of the cover membrane 11, with a portion of the support member 12 being located outside the distal end 18 of the cover membrane 11 and another portion of the support member 12 being located within the cover membrane 11. The impeller 5 is fixedly arranged on an impeller shaft 6, the impeller shaft 6 is rotatably sleeved in the support member 12, and the distal end of the impeller shaft 6 is rotatably supported in the distal bearing chamber 15. The distal end of the support member 12 is fixedly connected to a distal bearing chamber 15.

The support member 12 is of spindle configuration as a whole, providing a support space to accommodate the impeller 5. The proximal end of the support member 12 is connected to the distal end of the catheter 2. The proximal end of the support member 12 of the pump body 1 is fixedly connected to the distal end of the catheter 2. The proximal end 17 of the coating 11 is secured to the outer wall of the catheter 2 on the proximal side of the support member 12.

The distal end of the catheter 2 has a proximal bearing chamber 7, through which proximal bearing chamber 7 a proximal collar 125 of the support member 12 is connected, the proximal bearing chamber 7 being provided with a proximal bearing for rotational support of the drive shaft. A distal bearing chamber 15 is provided at the distal end of the drive shaft and rotatably supports the distal end of the drive shaft by a distal bearing. The distal end of the support member 12 is fixedly connected to the distal bearing chamber 15, and the spacing between the proximal bearing chamber 7 and the distal bearing chamber 15 is maintained by the support member 12, thereby providing stable rotational support for the impeller shaft 6.

The distal end of the distal bearing chamber 15 is also fixedly connected with an atraumatic support 8. The non-invasive support member 8 is a flexible pipe structure, and is represented as a flexible bulge (pigtail or tip chamber) with an end part in an arc shape or a winding shape, so that the flexible end part is supported on the inner wall of the heart chamber in a non-invasive or non-destructive manner, a suction inlet (a blood inlet 13) of the pump body 1 is separated from the inner wall of the heart chamber, the suction inlet of the pump body 1 is prevented from being attached to the inner wall of the heart chamber due to the reactive force of fluid (blood) in the working process of the pump body 1, and the suction effective area of the pump body 1 is ensured.

The pump body 1 is a collapsible pump body. The small size of the pump body 1 is desirable from the viewpoint of alleviating pain of the subject and ease of intervention. The pump body 1 is expected to have a large flow rate due to the strong auxiliary function provided for the subject, and the large flow rate generally requires the large size of the pump body 1.

By arranging the foldable pump body 1, the pump body 1 has smaller folding size and larger unfolding size, so that the requirements of relieving the pain of a subject in the intervention/conveying process, ensuring easy intervention and providing large flow are met.

As a result of the foregoing, the multi-mesh, and in particular diamond-shaped mesh design of the support member 12 allows for superior collapsing while allowing for deployment by the memory properties of nitinol.

The blades 50 are made of a flexible elastic material, and store energy when being folded, and after the external constraint is removed, the stored energy of the blades 50 is released, so that the blades 50 are unfolded.

The pump body 1 is folded by means of external constraint, and after the constraint is removed, the pump body 1 is self-unfolded. In the present embodiment, the "collapsed state" refers to a state in which the pump body 1 is radially constrained, that is, a state in which the pump body 1 is radially compressed and folded into a minimum radial dimension by external pressure. The "developed state" refers to a state in which the pump body 1 is not radially constrained, that is, a state in which the bracket and the impeller 5 are developed radially outward to the maximum radial dimension.

The application of the external restraint described above is accomplished by a folded sheath (not shown) that is slidably fitted over the catheter 2. When the folding sheath pipe moves forwards outside the guide pipe 2, the pump body 1 can be integrally contained in the folding sheath pipe, and the forced folding of the pump body 1 is realized. When the folding sheath moves backward, the radial constraint on the pump body 1 disappears, and the pump body 1 is unfolded.

As described above, the folding of the pump body 1 is achieved by the radial constraining force applied by the folding sheath tube. The impeller 5 included in the pump body 1 is accommodated in the pump housing 10, and therefore, in essence, the folding process of the pump body 1 is: the folded sheath exerts a radial restraining force on the pump casing 10, and when the pump casing 10 is radially compressed, the radial restraining force is exerted on the impeller 5.

That is, the pump casing 10 is folded directly by the folding sheath, and the impeller 5 is folded directly by the pump casing 10. As described above, the impeller 5 has elasticity. Thus, despite being in the collapsed state, the impeller 5 is collapsed to store energy so that it always has a tendency to radially expand, and the impeller 5 will come into contact with the inner wall of the pump casing 10 and exert a reaction force on the pump casing 10.

After the constraint of the folding sheath is removed, the pump shell 10 supports the elastic coating film 11 to be unfolded under the action of the self memory characteristic, and the impeller 5 is automatically unfolded under the action of released energy storage. In the deployed state, the outer diameter of the impeller 5 is smaller than the inner diameter of the pump casing 10.

Thus, the radially outer end of the impeller 5 (i.e., the tip of the blade 50) is kept spaced from the inner wall of the pump casing 10 (specifically, the inner wall of the bracket), which is a pump gap. The presence of the pump gap allows the impeller 5 to rotate unimpeded without wall impingement.

Furthermore, it is desirable that the pump gap size be of a small value and maintained for hydrodynamic considerations. In the present embodiment, the outer diameter of the impeller 5 is slightly smaller than the inner diameter of the holder as the support member 12, so that the pump clearance is as small as possible while satisfying that the impeller 5 rotates without hitting the wall. The main means for maintaining the pump gap is the support strength provided by the support member 12 and the tensile deformation resistance of the coating 11, which support strength and toughness of the coating 11 can resist the action of the back pressure of the fluid (blood) without excessive deformation, and thus the shape of the pump housing 10 is maintained stable, and the pump gap is also maintained stably.

The folding and unfolding processes of the pump body 1 are as follows:

during the intervention of the pump body 1 in the left ventricle, the pump body 1 is in a radially constrained state (collapsed state) due to an externally applied radially constraining force. After intervention in the left ventricle and removal of the radial constraint, the support member 12 expands autonomously by means of the memory characteristics of itself and release of the energy accumulation by the blades 50 of the impeller 5, so that the pump body 1 automatically assumes its unconstrained shape (deployed state).

On the contrary, when the pump body 1 needs to be withdrawn from the body of the subject after completing the work, the folding sheath is used for folding the pump body 1, and after the pump body 1 is completely withdrawn from the body of the subject, the constraint of the folding sheath on the pump body 1 is removed, so that the pump body 1 is restored to the natural state with the minimum stress, namely the unfolded state.

The above description is only a few embodiments of the present invention, and those skilled in the art can make various changes or modifications to the embodiments of the present invention according to the disclosure of the application document without departing from the spirit and scope of the present invention.

Claims

1. A pump body for an interventional catheter pump, the pump body being capable of being delivered to a desired location of a heart to pump blood; the method comprises the following steps: a pump housing having a blood inlet and a blood outlet, an impeller housed in the pump housing and configured to provide power to a flow of blood; the pump housing includes at least a cover defining a blood flow passage;

wherein the pump body comprises a radially collapsed state and a radially expanded state, the pump body being operatively switchable between the radially collapsed state and the radially expanded state;

the cover membrane is configured to not undergo tensile deformation when the pump casing is in the radially expanded state as compared to an unstressed state.

2. The pump body of claim 1, wherein the pump body includes an operating condition corresponding to rotation of the impeller; in the operating state of the pump body, the blood backpressure exerted on the membrane caused by the rotation of the impeller causes the folds of the membrane to be at least partially flattened.

3. A pump body for an interventional catheter pump, the pump body being capable of being delivered to a desired location of a heart to pump blood; the method comprises the following steps: a pump housing having a blood inlet and a blood outlet, an impeller housed within the pump housing for providing power to the flow of blood; the pump housing includes at least a cover defining a blood flow passage;

wherein the pump body comprises a radially collapsed state adapted for delivery within a subject's vasculature, a naturally expanded state corresponding to when the impeller is not rotating, and an operative state corresponding to when the impeller is rotating;

during the switching of the pump body from the natural deployment state to the working state, the blood backpressure exerted on the membrane caused by the rotation of the impeller causes the folds of the membrane to be at least partially flattened.

4. The pump body of claim 3, wherein flattening of the corrugations increases a diameter of the overlay film.

5. The pump body according to claim 4, wherein flattening of the corrugations causes an increase in diameter of the membrane of no more than 3%.

6. The pump body of claim 3, wherein the membrane has at least a sub-process of no diameter increase during transition of the pump housing from the naturally deployed state to the operational state.

7. The pump body of claim 3, wherein the cover is configured to not stretch-deform when the pump casing is in the naturally deployed or operational state as compared to an unstressed state.

8. The pump body according to claim 1, 2 or 3, wherein the pump casing further includes a support member for supporting the spread film; the radially deployed state comprises a natural deployed state corresponding to when the impeller does not rotate;

the membrane is configured such that a critical point stress causing tensile deformation thereof is equal to or greater than a force applied thereto by the support member when the pump casing is in the naturally expanded state.

9. The pump body of claim 8, wherein the radially expanded state further comprises an operating state corresponding to rotation of the impeller;

the stress of the critical point of the film at which the film is subjected to tensile deformation is greater than or equal to the force applied to the film by blood backpressure caused by the rotation of the impeller when the pump body is in the maximum working condition.

10. The pump body of claim 8, wherein the cover membrane is configured to have a material strength sufficient to itself resist the outward expansion tension of the support member, whereby the cover membrane has a circumferential tensile deformation amount of 0 when the pump casing is switched from the radially collapsed state to the naturally expanded state.

11. The pump body according to claim 9, wherein the film is configured to have a material strength sufficient for itself to resist a force applied thereto by a blood back pressure due to rotation of the impeller, and a circumferential tensile deformation amount of the film when the pump case is switched from the naturally expanded state to the operating state is 0.

12. The pump body of claim 9, wherein the membrane has a diameter in an operational state of the pump body that is greater than a diameter of the pump body in a naturally deployed state.

13. A pump body for an interventional catheter pump, the pump body being capable of being delivered to a desired location of a heart to pump blood; the method comprises the following steps: a pump housing having a blood inlet and a blood outlet, an impeller housed in the pump housing and configured to provide power to a flow of blood; the pump housing includes at least a cover defining a blood flow passage;

the diameter of the film in the working state of the pump body is larger than that of the film in the natural unfolding state of the pump body.

14. The pump body of claim 13, wherein the pump housing further includes a support member for supporting deployment of the membrane; in the naturally deployed state of the pump casing, the support member is radially constrained by the coating film without being fully deployed.

15. The pump body of claim 13, wherein the pump housing further includes a support member for supporting deployment of the membrane; in the naturally expanded state of the pump case, the support member has a contact support portion that contacts the film; in the operating state of the pump case, at least a part of the contact support portion is spaced apart from the coating film.

16. The pump body of claim 13, wherein the membrane includes a cylindrical section, a proximal tapered section disposed at a proximal end of the cylindrical section; the blood inlet extends to the cylindrical section at the proximal conical section; wherein part of the blood outlet is located in the proximal conical section, and the other part of the blood outlet is located in the cylindrical section; the blood inlet port, at least part of the axial length, tapers in circumferential width as it extends proximally from its distal end; alternatively, the length of the blood outlet is greater in the proximal conical section than in the cylindrical section.

17. The pump body of any one of claims 1-16, wherein the coating is made of TPU, PTFE, or PEBAX.

18. An interventional catheter pump, comprising:

a conduit;

a drive shaft disposed through the conduit;

a power assembly coupled to the drive shaft proximal end;

the pump body according to any one of claims 1-17, wherein the impeller of the pump body is connected to a distal end of the drive shaft.