Detailed Description
Referring to fig. 1, a catheter pump 100 according to an embodiment of the present invention may be at least partially inserted into a subject to assist in the pumping function of the heart and reduce the heart burden. Catheter pump 100 may act as a left ventricular assist, pumping blood in the left ventricle into the ascending aorta. It can also be used as a right ventricular assist to pump venous blood to the right ventricle.
The scenario will be described below primarily with catheter pump 100 as left ventricular assist. It will be appreciated from the foregoing that the scope of embodiments of the invention is not limited thereby.
Catheter pump 100 includes a motor 1, a catheter 2, a collapsible pump head 3 that can be delivered through catheter 2 to a desired location of a subject's heart, such as the left ventricle, for pumping blood, and a coupler 4 connected to the proximal end of catheter 2 for releasable engagement with motor 1. The collapsible pump head 3 comprises a pump housing 31 connected to the distal end of the catheter 2 and having an inlet end 311 and an outlet end 312, and an impeller (not shown) provided within the pump housing 31.
The pump housing 31 includes a support 313 made of nickel, titanium alloy in a metallic lattice and an elastic coating 314 covering the support 313. The metal lattice of the support 313 has a mesh design, and the cover 314 covers the middle and rear end portions of the support 313, and the mesh of the portion of the front end of the support 313 not covered by the cover 314 forms the inlet end 311. The rear end of the covering film 314 is covered outside the distal end of the catheter 2, and the outlet end 312 is an opening formed at the rear end of the covering film 314.
The impeller comprises a hub and blades supported on the outer wall of the hub. The impeller can be driven in rotation to draw blood into the pump housing 31 from the inlet end 311 and out the outlet end 312.
Catheter pump 100 further comprises a drive shaft (not shown) rotatably disposed through catheter 2, the proximal end of the drive shaft being connectable to motor 1 and the distal end of the drive shaft being connected to the impeller to transfer rotation of motor 1 to the impeller for pumping blood.
The drive shaft comprises a flexible shaft which is flexible and a hard shaft which is connected to the distal end of the flexible shaft, the flexible shaft is penetrated in the catheter 2, and the hard shaft is penetrated in the hub.
The proximal and distal ends of the support 313 are connected to a proximal bearing housing (not shown) and a distal bearing housing 32, respectively, and proximal and distal bearings (not shown) are provided in the proximal and distal bearing housings 32, respectively. The proximal end and the distal end of the hard shaft are respectively penetrated in the proximal end bearing and the distal end bearing. Thus, the two ends of the hard shaft are supported by the two bearings, and the high rigidity of the hard shaft allows the impeller to be preferably held in the pump housing 31.
The motor 1 has a motor shaft and a socket formed at the front end of the motor housing for mating with the coupler 4. The hub includes an active magnet coupled to the motor shaft. The coupler 4 comprises a passive magnet connected to the proximal end of the drive shaft. The disassembly of the motor 1 and the catheter 2 is realized by the disassembly of the connector and the coupler 4.
The pump head 3 and the front end portion of the catheter 2 are fed into and held in the subject, and it is desirable that the size of the pump head 3 and the catheter 2 be as small as possible. The smaller size pump head 3 and catheter 2 can enter the subject's body through the smaller puncture size, reducing the pain of the subject caused by the interventional procedure, and reducing complications caused by oversized puncture.
The dimensions and the hydrodynamic properties of the pump head 3 are two mutually contradictory parameters in the art. From the viewpoints of alleviating pain of a subject and ease of intervention, it is desirable that the pump head 3 be small in size. However, in order to provide a strong assist function to the subject, it is desirable that the flow rate of the pump head 3 is large, and the large flow rate generally requires the pump head 3 to be large in size.
Therefore, in order to reduce the size of the puncture and to ensure a large flow rate of the pump head 3, the pump head 3 is a collapsible pump having a collapsed state and an expanded state. In particular, in the corresponding insertion configuration of the pump head 3, the pump housing and the impeller are in a collapsed state, the pump head 3 being inserted into and/or delivered in the subject's vasculature at a first smaller outer diameter dimension. In the corresponding operating configuration of the pump head 3, the pump housing and the impeller are in a deployed state such that the pump head 3 pumps blood at a desired location with a second radial dimension that is greater than the first radial dimension.
By providing the collapsible pump head 3, the pump head 3 has a smaller collapsed size and a larger expanded size, so as to reduce pain of a subject and ease intervention in the intervention/transportation process, and provide a large flow.
By the above, the design of the multi-mesh, especially diamond-shaped mesh, of the pump housing 31 can realize the preferable folding and unfolding by the memory property of the nickel-titanium alloy. The blades of the impeller are made of flexible materials or shape memory materials, can be bent relative to the hub, and have a folded configuration and an unfolded configuration. The blade tip of the blade in the collapsed configuration is proximate to the hub and the blade tip of the blade in the expanded configuration is distal to the hub. The energy storage of the blade is released after the external constraint is removed, so that the blade is unfolded.
In the corresponding insertion configuration of the pump head 3, the blades are in a folded configuration, which wraps around the hub outer wall and is at least partially in contact with the inner wall of the pump housing 31. In the corresponding operating configuration of the pump head 3, the blades, when in the deployed configuration, extend radially outwardly from the hub and are spaced from the inner wall of the pump head 3.
The pump head 3 is folded by means of external constraint, and after the constraint is removed, the pump head 3 is self-unfolded. In the present embodiment, the "collapsed state" refers to a state in which the pump head 3 is radially restrained, that is, a state in which the pump head 3 is radially compressed and collapsed to a minimum radial dimension by external pressure. The "deployed state" refers to a state in which the pump head 3 is not radially constrained, that is, a state in which the bracket 313 and the impeller are deployed radially outward to the maximum radial dimension.
Referring to fig. 2 and 3, catheter pump 100 further comprises a radial crimping device 5, and switching of pump head 3 between the deployed and collapsed states may be accomplished by radial crimping device 5. The radial crimping device 5 is adapted to compress the pump head 3 in the deployed state to the collapsed state.
The radial crimping apparatus 5 includes a repeatable compression member 51 and an operating member 52 that cooperates with the repeatable compression member 51. The repeatable compression member 51 is made of a flexible and elastic material, and is deformable by an external force and returns to its original shape after the external force is removed. The flexible material may be a material such as silica gel, and is not specifically mentioned herein.
The repeatable compression member 51 has an axially pre-folded channel 511 for receiving the pump head 3. The operating member 52 exerts a force on the repeatable compression member 51 having a first state that exerts a first force on the repeatable compression member 51 and a second state that exerts a second force on the repeatable compression member 51.
The first inner diameter of the pre-folding channel 511 when the operating member 52 is in the first state is at least not smaller than the outer diameter of the pump head 3 in the unfolded state. At this time, the pre-folding passage 511 facilitates the smooth entry of the pump head 3 therein.
The first force is less than the second force and the second inner diameter of the pre-folded channel 511 when the operating member 52 is in the second state is less than the first inner diameter. The second inner diameter of the pre-folded channel 511 when the operating member 52 is in the second state defines the outer diameter of the pump head 3 in the folded state. That is, the second inner diameter dimension of the pre-folded channel 511 is equal to the outer diameter dimension of the pump head 3 in the folded state. When the pre-folding channel 511 is switched from the first inner diameter to the second inner diameter, folding of the pump head 3 is achieved.
For ease of operation, the first force applied by the operating member 52 to the repeatable compression element 51 may be zero when the operating member 52 is in the first state. So that no operation is required, the operating member 52 is kept in the first state, and the pre-folding passage 511 is kept at the first inner diameter, at which time the pump head 3 can be easily introduced into the pre-folding passage 511.
In the present embodiment, the operating member 52 is in contact engagement with the repeatable compression element 51 along the axial end, and the operating member 52 is switched between the first state and the second state by moving in the axial direction. The operating member 52 has an operating passage 521 communicating with the pre-folding passage 511, and the pump head 3 is movable to the pre-folding passage 511 through the operating passage 521. At least not smaller than the outer diameter of the pump head 3 in the expanded state of the operation passage 521 so that the pump head 3 passes smoothly.
The radial crimping apparatus 5 further includes a sleeve 53 which receives the repeatable compression element 51 therein, the sleeve 53 maintaining the outer diameter of the repeatable compression element 51 when the operating element 52 is switched from the first state to the second state. That is, the sleeve 53 limits the outer diameter of the repeatable compression element 51, ensuring that only the inner diameter of the repeatable compression element 51 changes when subjected to an external force.
In addition, the operating member 52 applies a force to the repeatable compression element 51 by moving in the axial direction, and in order to limit the axial movement of the repeatable compression element 51 under the force, the sleeve 53 is provided with a stop end 531 at an end of the repeatable compression element 51 away from the operating member 52, thereby saving the force applied to the operating member 52 and facilitating the operation.
In order to facilitate the subsequent pushing out of the pump head 3 in the folded state from the radial press-holding device 5, the inner wall of the stop end 531 gradually tapers from the proximal end to the distal end. When the pump head 3 moves out of the pre-folding channel 511, the inner diameter size gradually decreases due to the gradual shrinkage of the stop end 531, the pump head 3 is slowly and gradually folded, the folding force is reduced, and the smoothness of the pump head 3 moving out of the radial pressing device 5 is improved.
In order to facilitate the switching of the operation member 52 between the first state and the second state, the operation member 52 and the sleeve 53 may be screwed, the operation member 52 may be rotated toward the front end to switch the operation member 52 to the second state, and the operation member 52 may be rotated toward the rear end to switch the operation member 52 to the first state, thereby improving the operability of the user.
In another embodiment, the operating member 52 may circumferentially encase the repeatable compression member 51, the operating member 52 being switched between the first and second states by moving in a radial direction, enabling the pump head 3 located within the pre-collapse channel 511 to be switched between the expanded and collapsed states. The manner of the interface between the operating member 52 and the repeatable compression member 51 is not particularly limited herein.
The radial crimping device 5 may be separately disposed from the catheter pump 100 with the operating member 52 at the proximal end and the introduction tube 55 at the distal end, and the distal end of the pump head 3 is inserted into the operating channel 521 and enters the pre-crimping channel 511 to switch the operating member 52 to the second state, the pre-crimping channel 511 to the second inner diameter, and the pump head 3 to the crimping state by pulling the radial crimping device 5 rearward, pushing the catheter 2 forward, or pulling the radial crimping device 5 rearward while pushing the catheter 2 forward.
The external restraint imposed on the pump head 3 is accomplished by the radial crimping device 5. When the operating member 52 is in the first state, the pump head 3 is entirely accommodated in the pre-folding passage 511. When the operation member 52 is switched to the second state, the repeatable compression member 51 is at the second inner diameter, and the pump head 3 is subjected to radial folding force, so that the forced folding of the pump head 3 is realized. The folding force is small, the doctor can operate more conveniently and labor-saving, and the operation efficiency is greatly improved. And because the pump head 3 receives radial folding force instead of axial folding force due to a pulling mode, the pump head 3 is not easy to damage and has high safety.
The catheter pump 100 comprises a protecting head 6 connected to the distal end of the pump head 3, and in order for the radial crimping device 5 to smoothly collapse the pump head 3 from the distal end, the protecting head 6 extends along the axis of the pump head 3, that is, the protecting head 6 is linear, so that the distal end can smoothly enter into the radial crimping device 5. In addition, the protective head 6 is configured to be flexible so as not to injure the tissue of the subject, the protective head 6 may be made of any material that macroscopically exhibits flexibility, the flexible end portion of which is supported on the inner wall of the ventricle in a non-invasive or atraumatic manner, separating the suction inlet of the pump head 3 from the inner wall of the ventricle, avoiding the suction inlet of the pump head 3 from adhering to the inner wall of the ventricle due to the reaction force of the fluid (blood) during operation of the pump head 3, ensuring the effective area of pumping.
The present invention provides a method of folding a pump head of a catheter pump as shown above, comprising:
pushing the catheter forward and/or pulling the radial pressing device backward, and inserting the distal end of the pump head into the pre-folding channel;
the operation piece is switched from the first state to the second state, so that the pre-folding channel is switched to the second inner diameter, and the pump head is switched to the folding state.
The radial pressing device and the catheter pump are arranged separately, the operating piece is in a first state, the catheter is pushed forward, or the radial pressing device is pulled backward while the catheter is pushed forward, and the distal end of the pump head enters the pre-folding channel through the operating channel. The specific operation of switching the pump head to the folded state is described above and will not be described in detail herein. The pump head is collapsed for subsequent delivery to the vasculature of the subject.
Referring to fig. 4 to 7, a catheter pump 200 according to another embodiment of the present invention is substantially the same as the catheter pump 100 provided in the above embodiment, and is not described herein, except that the catheter pump 200 according to the present embodiment further includes an insertion sheath 7, and the insertion sheath 7 includes an insertion channel 71 capable of receiving the pump head 3. The radial crimping apparatus 5 is operably docked with the access sheath 7 such that the access channel 71 and the pre-crimping channel 511 are in communication.
The manner in which the radial pressing device 5 folds the pump head 3 is described above and will not be described in detail here.
The distal end of the radial crimping apparatus 5 is operably engaged with the proximal end of the access sheath 7 to advance the catheter 2 so that the pump head 3 in the collapsed state is transferred from the pre-collapsed channel 511 into the access sheath 7.
Wherein the radial crimping device 5 is operably docked with the access sheath 7 in such a way that the distal end of the sleeve 53 of the radial crimping device 5 and the proximal end of the access sheath 7 are end-wise docked to achieve communication between the pre-crimping passage 511 and the access passage 71.
To facilitate docking of the radial crimping apparatus 5 with the access sheath 7, the radial crimping apparatus 5 further comprises an ingress tube 55 defining a straight lumen 551, the proximal end of the straight lumen 551 being in communication with the distal end of the pre-folded channel 511, the pump head 3 being transferred from the pre-folded channel 511 into the straight lumen 551 and into the access channel 71 when the operating member 52 is in the second state. The dimension of the straight cavity 551 is equal to the outer diameter dimension of the pump head 3 in the collapsed state.
The material of the inlet tube 55 is PTFE. By using the PTFE material having a low friction coefficient, the conveying force of the pump head 3 during relative movement in the introduction pipe 55 can be effectively reduced, and the conveying compliance can be improved. In other embodiments, the material of the inlet tube 55 may be other materials with low friction coefficient, which are not listed here.
Another way in which the radial crimping apparatus 5 is operably docked with the access sheath 7 may be for the introduction tube 55 of the radial crimping apparatus 5 to be at least partially operably threaded into the access sheath 7 to enable communication between the pre-crimping passage 511 and the access passage 71 through the straight lumen 551 of the introduction tube 55.
Yet another way in which the radial crimping apparatus 5 may be operably docked with the access sheath 7 is by end-face docking of the distal end of the introduction tube 55 of the radial crimping apparatus 5 with the proximal end of the access sheath 7 to enable communication between the pre-crimping passage 511 and the access passage 71 through the straight lumen 551 of the introduction tube 55.
The pump head 3 is delivered to the vasculature through the access sheath 7 in a collapsed state, enabling the pump head 3 to enter the subject with a smaller access size.
The insertion sheath 7 has an inner diameter smaller than the outer diameter of the coupler 4 and is partially inserted into the vasculature of the subject through the puncture. The interventional sheath 7 has a forward end that enters the vasculature through the puncture and a rearward end that remains outside the body for forming or establishing access for the device into the vasculature.
The second inner diameter of the pre-folded channel 511 when the operating member 52 is in the second state is smaller than or equal to the inner diameter of the access sheath 7, so that the pump head 3 can be smoothly transferred from the pre-folded channel 511 into the access sheath 7. The inner diameter of the same introduction tube 55 is also smaller than or equal to the inner diameter of the insertion sheath 7.
In this embodiment, the distal end of the introducing tube 55 and the proximal end of the insertion sheath 7 are used for end-face butt joint, and when the pump head 3 is inserted into the body of the subject, the introducing tube 55 does not enter the body, so that the size of the insertion sheath 7 is reduced, the related complications caused by insertion puncture are greatly reduced, and the operation safety is improved.
In an embodiment, the outer diameter of the introduction tube 55 may be less than or equal to the inner diameter of the access sheath 7 to achieve at least partial operable penetration of the introduction tube 55 into the access sheath 7.
When the catheter pump 200 is inserted into the body of the subject to assist in pumping blood, the catheter pump 200 is kept in the body of the subject, and the insertion sheath 7 is kept in the puncture.
The distal end of the radial crimping device 5 is provided with a first part 56 and the proximal end of the access sheath 7 is provided with a second part 72 cooperating with the first part 56, the first part 56 and the second part 72 being detachably locked.
The radial crimping device 5 and the access sheath 7 are subjected to a relative rotational movement to effect locking or unlocking of the first part 56 and the second part 72; wherein the angle of rotation does not exceed 90 °.
Specifically, one of the first member 56 and the second member 72 is a projection, and the other of the first member 56 and the second member 72 has a stopper wall that mates with the projection, and the projection and the stopper wall abut when the introduction tube 55 is locked with the insertion sheath 7.
The number of the first parts 56 and the second parts 72 is two, the two first parts 56 are oppositely arranged at two sides of the ingress pipe 55, and the two second parts 72 are also arranged at two sides of the intervention sheath 7, so that locking stability of the radial pressing device 5 and the intervention sheath 7 is improved.
In this embodiment, the first member 56 is a T-shaped slot having two stop walls, and the radial crimping device 5 and the insertion sheath 7 are selectively rotated clockwise or counterclockwise when they are subjected to relative rotational movement, and the second member 72 is abutted against the stop walls to improve operability.
When the distal end of the radial crimping device 5 and the access sheath 7 are docked, the pump head 3 is transferred from the pre-crimping channel 511 into the access channel 71 by pushing the catheter 2 forward. At this time, the first member 56 and the second member 72 are locked, and the radial pressure holding device 5 and the insertion sheath 7 cannot be separated relatively. Thereby preventing the transfer of the pump head 3 from the pre-folding channel 511 to the intervention channel 71 caused by the separation of the radial pressing device 5 from the intervention sheath 7 due to the backward movement of the radial pressing device 5 due to the reaction force of the pump head 3 when the catheter 2 is pushed forward, and also preventing the intervention sheath 7 from moving at the puncture under the action of external force to destroy the puncture during the transfer of the pump head 3. Ensuring the size of the puncture opening, being beneficial to the healing of the puncture opening and reducing the complication probability of the puncture opening, and simultaneously relieving the pain of the subject.
The radial crimping device 5 is operably peeled off after the pump head 3 has entered the vasculature, and the access sheath 7 is threaded through the puncture, thereby avoiding interference of the radial crimping device 5 with the coupler 4.
The axis of the ingress pipe 55 is provided with a pre-pressing tearing seam or a lateral opening, and the operating piece 52 and the sleeve 53 can be designed into a two-flap structure so as to be convenient to peel.
The operating member 52 and the sleeve 53 may be made of polytetrafluoroethylene, and are integrally formed into a two-half symmetrical and completely identical structure by a stamping process, and the two-half symmetrical and completely identical structure is butted by a hot melting process to form a pre-pressing tear seam at the butted position.
The sleeve 53 is further sleeved with a clamping sleeve 54 to ensure circumferential fixation of the operating member 52 and the sleeve 53 in a two-piece structure and prevent circumferential movement of the operating member 52 and the sleeve 53.
The proximal end of the access sheath 7 is provided with an introduction seat 73, the introduction seat 73 being used for fixing and sealing the catheter 2. The three-way extension pipe 74 is disposed on the guiding seat 73, and the three-way extension pipe 74 is a prior art and will not be described herein.
The proximal end of the access sheath 7 has a hemostatic valve 75, and when the pump head is operably threaded into the access sheath 7, blood in the blood vessel is prevented from exiting the body through the hollow structure of the access sheath 7 by the hemostatic valve 75.
The hemostatic valve may be a balloon, a flexible material such as rubber, and the like, which is an existing structure and will not be described herein.
The present invention also provides a method of folding a pump head of a catheter pump as described above, comprising:
pushing the catheter forward and/or pulling the radial pressing device backward, and inserting the distal end of the pump head into the pre-folding channel;
the operation piece is operated to switch from the first state to the second state, so that the pre-folding channel is switched to the second inner diameter, and the pump head is switched to the folding state;
the distal end of the radial pressing and holding device is butted with the proximal end of the interventional sheath, and the catheter is pushed forward, so that the pump head in the folded state is transferred into the interventional sheath through the pre-folded channel when the operating piece is in the second state.
The folding of the pump head into the pre-folding channel is described above and will not be described in detail here.
In the process that the pump head is transferred into the intervention sheath by the pre-folding channel, the radial pressing and holding device and the intervention sheath are axially kept fixed, and concretely, the pump head is realized by locking the first component and the second component.
Wherein the interventional sheath is partially inserted into the vasculature of the subject through the puncture, the method further comprising, after the pump head is transferred into the interventional sheath: the catheter is continuously pushed forward, the pump head is moved out of the distal end of the intervention sheath, enters the vascular system of the subject in a unfolding state and is inserted to a target position, and the motor is connected with the catheter in a matched mode, so that the blood pumping working state of the catheter pump can be realized.
After the pump head is transferred into the interventional sheath, the method further comprises: the radial crimping device is operable to peel apart. The clamp sleeve is removed firstly, the operation piece and the sleeve with the two-flap structure and the ingress pipe with the prepressing tearing seam or the lateral opening can be peeled off under the action of external force, the structure of the external part of the catheter after the catheter pump is inserted into the human body is simplified, and the operation post-nursing of doctors is facilitated.
It should be noted that, the insertion sheath is always partially inserted into the puncture, so as to facilitate the subsequent operation of removing the pump head from the subject.
When the catheter pump assisted pumping is completed, the catheter pump is removed from the subject as: pulling the catheter proximally to house the pump in the deployed state within the insertion sheath to switch the pump head to the collapsed state; the catheter is continued to be pulled proximally, removing the pump head from the interventional sheath. Finally, the interventional sheath is pulled proximally to be removed from the body.
The operation piece is matched with the repeatable compression piece, the operation piece applies acting force to the repeatable compression piece, so that the inner diameter of a pre-folding channel of the repeatable compression piece is changed from at least not smaller than the outer diameter of the pump head in an unfolding state to smaller, the outer diameter of the pump head positioned in the pre-folding channel is reduced accordingly, the folding of the pump head is realized, the radial folding force is received by the pump head, the folding force is small, the operation of doctors is more convenient and labor-saving, and the operation efficiency is greatly improved. And because the pump head receives radial folding force instead of axial folding force due to a pulling mode, the pump head is not easy to damage and has high safety.
The foregoing is merely a few embodiments of the present invention and those skilled in the art may make various modifications or alterations to the embodiments of the present invention in light of the disclosure herein without departing from the spirit and scope of the invention.