Catheter pump

Abstract

A catheter pump (1000) having a drive catheter handle (204) comprising a coupling housing (2045) detachably connected to a motor (102), a proximal end of a drive shaft (202) being connected to a rotor (2046), the rotor (2046) transmitting rotational power of the motor (102) to the drive shaft (202), thereby driving an impeller (2052) of a pump head (205) to rotate. A containing cavity (2049) which supports the rotor (2046) therein and is communicated with the guide pipe (201) is formed in the coupling shell (2045), and a flushing fluid inlet (2043) and a flushing fluid outlet (246) which are communicated with the containing cavity (2049) are formed in the coupling shell (2045). The flushing fluid inlet (2043) and the flushing fluid outlet (246) are communicated with a flushing fluid inlet pipe (501) and a flushing fluid outlet pipe (502) respectively, the flushing fluid outlet pipe (502) is communicated with the flushing fluid inlet pipe (501), the flushing fluid outlet pipe (502), the flushing fluid inlet pipe (501) and the containing cavity (2049) form a cooling circulation loop, and a circulation driving part (503) is arranged on the cooling circulation loop. The cooling circulation loop is connected with a pressure maintaining module (600) used for maintaining the pressure of the flushing liquid in the cooling circulation loop.

Description

Catheter pump Technical Field

[0001] The present application relates to a catheter pump. Background Art

[0002] Heart disease is a health problem with a high mortality rate, and physicians are increasingly using mechanical circulatory support systems to treat heart failure. Treating acute heart failure requires a device that can quickly provide support to the patient, and physicians want treatment options that can be deployed quickly and minimally invasively.

[0003] Mechanical circulatory support (MCS) systems and ventricular assist devices (VADs) are gaining increasing acceptance for the treatment of acute heart failure. For example, they are used to stabilize patients after an acute myocardial infarction (MI) or compensated heart failure, or to support patients during high-risk percutaneous coronary intervention (PCI). An example of an MCS system is a rotary catheter pump placed percutaneously via a catheter.

[0004] Conventionally, a catheter pump is inserted into the body and connected to the cardiovascular system (e.g., connecting the left ventricle to the ascending aorta) to assist the heart's pumping function. Other known applications include pumping venous blood from the right ventricle to the pulmonary artery to support the right side of the heart. Typically, acute circulatory support devices are used to reduce the workload on the myocardium for a period of time, stabilize the patient before heart transplantation, or provide continuous support.

[0005] For example, a known embodiment, such as publication number CN113856036A, provides a catheter pump that achieves a small interventional size by utilizing an external motor. The general operating principle of this catheter pump is as follows: the external motor transmits rotational power to the distal impeller via a drive shaft inserted into the catheter. The impeller's rotation provides flow motive force, pumping blood from the left ventricle to the aorta. During the impeller's power transmission process, multiple rotating components, such as the drive shaft and the proximal and distal bearings supporting the impeller, are involved. Therefore, during operation, the catheter needs to be flushed with fluid to lubricate and cool these rotating components.

[0006] To prevent flushing fluid leakage, particularly preventing it from entering the motor, current catheter pumps utilize non-contact power transmission mechanisms, including magnetic coupling solutions such as those provided in Publication No. CN101820933B and eddy current coupling solutions such as those provided in Publication No. CN114452527A and Publication No. CN216061675U. A liquid-isolating wall is placed between the driver and driven components (both are magnets in the magnetic coupling solution and a magnet and conductor in the eddy current coupling solution), sealing the flushing fluid. This allows the flushing fluid to flow only to the distal end, flushing the drive shaft and proximal and distal bearings without entering the motor.

[0007] The driving member is rotated by the motor, while the driven member is mounted on and supported by the rotor shaft, which is circumferentially fixed to the proximal end of the driving shaft. Thus, through the magnetic coupling between the driving member and the driven member, the motor's rotation is transmitted to the rotor shaft, and further to the driving shaft and impeller.

[0008] A rotor, comprising a driven member and a rotor shaft, is housed in a drive conduit handle removably connected to the motor. The rotor also includes a protective layer covering the driven member and an end cap that axially confines the driven member. The rotor shaft is rotatably supported in the drive conduit handle by two bearings. A flushing fluid port is provided on the drive conduit handle. This allows the flushing fluid to enter the drive conduit handle before entering the conduit. Consequently, the rotor is immersed in the flushing fluid. Consequently, the flushing fluid also lubricates and cools the two bearings supporting the rotor shaft.

[0009] It's worth noting that the torque of a contactless power transmission mechanism is inversely correlated with the distance between the driver and driven parts. This is particularly evident in eddy current couplings. Therefore, increasing the rotor diameter to reduce the distance between the driver and driven parts is a viable solution to increase the torque of power transmission.

[0010] However, increasing the rotor's diameter also reduces the distance between the rotor's outer wall and the inner wall of the drive catheter handle. In practice, it has been found that because the rotor is immersed in the flushing fluid, when the rotor rotates at high speed, the flushing fluid in the narrow space inside the drive catheter handle is driven by the rotor due to the fluid's viscosity, generating significant eddy current losses and, in turn, causing a significant temperature rise in the flushing fluid. Because the flushing fluid at least partially enters the human body through the catheter, this significant temperature rise can adversely affect the human body.

[0011] Therefore, how to solve the temperature rise of the flushing fluid is a technical problem that needs to be solved urgently. Summary of the Invention

[0012] In view of this, an embodiment of the present invention provides a catheter pump for at least partially solving the above-mentioned problem.

[0013] To achieve the above object, the present invention provides the following technical solutions:

[0014] The catheter pump includes a driving component, a working component, a cooling circulation module and a pressure maintaining module.

[0015] The drive assembly includes a motor.

[0016] The working assembly includes a catheter, a drive shaft passing through the catheter, a follower connected to the proximal end of the drive shaft, a drive catheter handle connected to the proximal and distal ends of the catheter respectively, and a pump head. The pump head includes a pump housing connected to the distal end of the catheter and an impeller housed in the pump housing. The impeller is connected to the distal end of the drive shaft so as to be driven to rotate to pump blood. The drive catheter handle includes a coupling housing connected to the proximal end of the catheter and detachably connected to the motor, a rotor driven by the motor, and the proximal end of the drive shaft is connected to the rotor. A accommodating chamber is formed in the coupling housing to rotatably support the rotor therein, and a flushing liquid inlet and a flushing liquid outlet connected to the accommodating chamber are provided on the coupling housing, and the accommodating chamber is connected to the catheter. The flushing liquid inlet is connected to a flushing liquid source, and the flushing liquid entering the accommodating chamber through the flushing liquid inlet is divided into two parts: the first part enters the catheter, and the second part passes through the rotor through the flushing liquid and is discharged from the flushing liquid outlet.

[0017] The first portion of flushing fluid is ultimately discharged from the pump head into the body. This means that the first portion of flushing fluid entering the catheter does not experience backflow and instead enters the body entirely. Backflow occurs when flushing fluid flows back through the catheter or drive shaft from the distal end (roughly where the pump head is located) to the proximal end (specifically, where the drive catheter handle is located).

[0018] The first part of the flushing fluid is mainly discharged at two locations on the distal end (pump head): the distal end of the catheter and the distal end of the drive shaft.

[0019] The catheter pump includes a first flow path for the flow of a first portion of flushing fluid. The first flow path is defined by the internal space of the flushing fluid inlet, the accommodating chamber, the catheter, and the pump head. Thus, the first portion of flushing fluid flows from the flushing fluid inlet into the accommodating chamber, from the accommodating chamber into the catheter, and ultimately out of the pump head.

[0020] The catheter pump also includes a second flow path for the flow of a second portion of the flushing liquid. The second flow path is defined by the internal space of the flushing liquid inlet, the accommodating chamber, and the flushing liquid outlet. Thus, the flow path of the second portion of the flushing liquid is from the flushing liquid inlet into the accommodating chamber and then out of the flushing liquid outlet.

[0021] It's worth noting that there's no clear interface between the first and second portions of flushing liquid during their flow. This description is used in this application for simplicity. For convenience, the flushing liquid that ultimately enters the catheter is defined as the first portion of flushing liquid, and the flushing liquid that ultimately exits the flushing liquid outlet is defined as the second portion of flushing liquid.

[0022] The disclosed technical solution allows for the diversion of irrigating fluid within the drive catheter handle. The first portion of irrigating fluid entering the catheter lubricates and cools rotating components such as the drive shaft and bearings as it flows toward the distal pump head. The second portion of irrigating fluid flowing out of the irrigating fluid outlet removes the high-speed heat generated by the rotor, thus preventing the irrigating fluid from becoming overheated.

[0023] The cooling circulation module includes a flushing liquid inlet pipe connected to the flushing liquid inlet and a flushing liquid outlet pipe connected to the flushing liquid outlet. The flushing liquid outlet pipe is connected to the flushing liquid inlet pipe, and the flushing liquid outlet pipe, the flushing liquid inlet pipe, and the accommodating chamber form a cooling circulation loop. The cooling circulation module also includes a circulation drive member provided in the cooling circulation loop for driving the flushing liquid to flow.

[0024] The pressure maintaining module is connected to the cooling circulation loop and is used to maintain the flushing liquid pressure in the cooling circulation loop to be greater than the ambient pressure of the pump head during operation.

[0025] A cooling circulation loop is established through the flushing liquid inlet and outlet pipes and the accommodating chamber. With the help of a circulating drive, most of the flushing liquid circulates in the cooling circulation loop, avoiding the formation of a flow dead zone in the accommodating chamber. This in turn avoids the high temperature caused by the eddy current loss of the flushing liquid due to the high-speed rotation of the rotor in the accommodating chamber. At the same time, the pressure maintenance module maintains the flushing liquid pressure in the cooling circulation loop greater than the ambient pressure of the pump head, allowing the flushing liquid to enter the human body through the catheter. Since the high temperature of the flushing liquid is solved, the flushing liquid entering the human body will not cause discomfort.

[0026] The circulation driving component is a first pump provided on the flushing liquid inlet pipe and / or the flushing liquid outlet pipe.

[0027] As described above, during the flow of the flushing liquid, part of it enters the catheter and part of it exits the flushing liquid outlet. Furthermore, the amount of flushing liquid entering the catheter (the first portion of flushing liquid) is less than the amount exiting the flushing liquid outlet (the second portion of flushing liquid). The term "amount" can refer to either volume or flow rate. This article uses flow rate as the basis for this description.

[0028] The above distribution of liquid flow can be achieved by controlling the pressure maintaining module to maintain the flushing liquid pressure in the cooling circulation loop greater than the ambient pressure of the pump head during operation.

[0029] The pressure maintenance module includes a flushing liquid source connected to the cooling circuit via a replenishment line, and a second pump located in the replenishment line to replenish the flushing liquid from the flushing liquid source into the cooling circuit. Thus, the power required to circulate the flushing liquid and the pressure required to maintain the flushing liquid pressure are respectively provided by the circulation drive and the second pump.

[0030] Since the pump control technology is relatively mature, when the circulation drive element uses the first pump, the first pump and the second pump respectively provide the power required for the circulation of the flushing liquid and the flushing liquid maintenance pressure, thereby achieving precise control of the flushing liquid flow into the human body.

[0031] To facilitate piping connections, the cooling circulation module also includes a buffer container. The flushing liquid inlet and outlet pipes, as well as the replenishing line, are all connected to the buffer container via Luer connectors. Furthermore, to partially offset the potential for pressure instability (or drop in pressure) caused by expansion of the flushing liquid inlet and outlet pipes when using flexible pipes, ultimately leading to unstable flushing liquid flow entering the body, the buffer container must be able to withstand the pressure replenishment of the pressure maintenance module without experiencing volume changes. A solid tank or T-joint, which maintains constant volume, is preferred.

[0032] To prevent gases released from the flushing fluid during high-speed rotor rotation from entering the human body, a bubble filter is installed in the cooling loop to capture or filter these bubbles. The bubble filter is preferably located on the flushing fluid inlet pipe to substantially prevent bubbles from entering the human body through the catheter. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG1 is a schematic diagram of the three-dimensional structure of a catheter pump according to an embodiment of the present invention;

[0034] FIG2 is a cross-sectional view of the front end pump head portion of the working assembly in FIG1 ;

[0035] FIG3 is a cross-sectional view of the drive assembly and the drive catheter handle in a separated state;

[0036] FIG4 is a simplified structural diagram of a high-temperature solution for flushing liquid corresponding to the third embodiment, in which the circulating drive member is a pump. Implementation Method

[0037] As used herein, the terms "proximal," "posterior," "distal," and "anterior" are used relative to the clinician operating the catheter pump. The terms "proximal" and "posterior" refer to the portion relatively close to the clinician, while the terms "distal" and "anterior" refer to the portion relatively far from the clinician. For example, the drive assembly is at the proximal and posterior end, while the working assembly is at the distal and anterior end. For another example, the proximal end of a component / assembly refers to the end relatively close to the drive assembly, while the distal end refers to the end relatively close to the working assembly.

[0038] It should be understood that the directions "proximal," "distal," "posterior," and "anterior" are defined for ease of description. However, the catheter pump can be used in many directions and positions, so these terms expressing relative positional relationships are not limiting and absolute.

[0039] The catheter pump of an embodiment of the present invention can at least partially assist the heart's pumping function, thereby at least partially alleviating the heart's workload. In one exemplary scenario, the catheter pump can be used to assist the left ventricle. Its working portion (specifically, the pump head below) can be inserted into the left ventricle. When the pump head is in operation, it can pump blood in the left ventricle into the ascending aorta.

[0040] It is worth noting that the aforementioned example of using the catheter pump as a left ventricular assist is only one possible application scenario for the present catheter pump. In other feasible and not explicitly excluded scenarios, the catheter pump can also be used to assist the right ventricle, with the pump head being inserted into the right ventricle and pumping blood from the veins into the right ventricle when the pump head is in operation.

[0041] The following mainly describes the scenario in which the catheter pump is used as a left ventricular assist device. However, based on the above description, it can be seen that the protection scope of the embodiments of the present invention is not limited thereby.

[0042] As shown in Figure 1, the catheter pump 1000 includes a drive assembly 100 and a working assembly 200. In conjunction with Figure 3, the drive assembly 100 includes a motor housing 101, a motor 102 housed in the motor housing 101, and an active member 103 driven by the motor 102. In conjunction with Figure 2, the working assembly 200 includes a catheter 201, a drive shaft 202 passing through the catheter 201, a driven member 203 connected to the proximal end of the drive shaft 202, and a drive catheter handle 204 and a pump head 205 connected to the proximal and distal ends of the catheter 201, respectively. The pump head 205 includes a pump housing 2051 having an inlet 2051a and an outlet 2051b, an impeller 2052 housed in the pump housing 2051, and the impeller 2052 is connected to the distal end of the drive shaft 202. When the impeller 2052 rotates, blood is sucked into the pump housing 2051 through the inlet 2051a and then pumped out of the pump housing 2051 through the outlet 2051b.

[0043] In one embodiment, the pump housing 2051 includes a bracket 20511 and an elastic coating 20512 covering the bracket 20511. The metal lattice structure of the bracket 20511 has a mesh design, and the coating 20512 covers the middle and rear ends of the bracket 20511. The mesh in the front end portion of the bracket 20511 not covered by the coating 20512 forms an inlet 2051a. The rear end of the coating 20512 covers the exterior of the distal end of the catheter, and the outlet 2051b is an opening formed at the rear end of the coating 20512. The impeller 2052 includes a hub 20521 and blades 20522 supported on the outer wall of the hub 20521. The blades 20522 are made of a flexible material and, together with the bracket 20511 and the coating 20512 made of the nickel-titanium memory alloy, form a foldable pump head 205.

[0044] Of course, in other embodiments, the pump head 205 may also be non-foldable. Accordingly, the pump housing 2051 may be a metal sleeve that is non-radially foldable and non-self-expandable. The impeller 2052 is also made of a hard but biocompatible material.

[0045] The drive shaft 202 includes a flexible soft shaft 2021 and a hard shaft 2022 connected to the distal end of the soft shaft 2021. The soft shaft 2021 is inserted into the catheter 201, and the hard shaft 2022 is inserted into the hollow channel of the hub 20521. The outer wall of the hard shaft 2022 and the inner wall of the hollow channel of the hub 20521 are fixed by bonding.

[0046] The proximal and distal ends of bracket 20511 are connected to proximal bearing chamber 206 and distal bearing chamber 207, respectively. Proximal bearing chamber 206 and distal bearing chamber 207 respectively house proximal bearing 208 and distal bearing 209. The proximal and distal ends of rigid shaft 2022 are respectively passed through proximal bearing 208 and distal bearing 209. Thus, rigid shaft 2022 is supported at both ends by bearings 208 and 209. Combined with the high rigidity of rigid shaft 2022, impeller 2052 is effectively retained within pump housing 2051.

[0047] As shown in FIG3 , the drive catheter handle 204 includes a coupling housing 2045, within which is disposed an irrigation bracket 2041 defining an irrigation lumen 2042. The proximal end of the catheter 201 passes through the coupling housing 2045, connects to the irrigation bracket 2041, and communicates with the irrigation lumen 2042. The drive catheter handle 204 is provided with an irrigation liquid inlet 2043 extending through the sidewall of the coupling housing 2045. The inner end of the irrigation liquid inlet 2043 communicates with the irrigation lumen 2042.

[0048] As described above, the magnetic coupling between the driving member 103 and the driven member 203 enables contactless power transmission. Furthermore, a liquid barrier 2048 can be provided between the driving member 103 and the driven member 203 or outside the driven member 203 to seal the flushing liquid and prevent it from entering the motor 102. Furthermore, the liquid barrier 2048 limits the flow direction of the flushing liquid, allowing it to flow only toward the distal end, i.e., the working assembly 200, thereby lubricating and cooling the rotating components of the working assembly 200, such as the drive shaft 202 and bearings.

[0049] As shown in FIG3 , the drive catheter handle 204 further includes a rotor 2046 rotatably disposed within a coupling housing 2045. The rotor 2046 includes a rotor shaft 2047 on which the driven member 203 is disposed. The proximal end of the drive shaft 202 is connected to the rotor shaft 2047. A liquid isolation wall 2048 is disposed within the coupling housing 2045 and is located at the rear end of the irrigation bracket 2041. The liquid isolation wall 2048 is abutted against the irrigation bracket 2041 and together define a housing chamber 2049 for receiving the rotor 2046 therein.

[0050] The accommodating chamber 2049 includes an irrigation chamber 2042 defined by an irrigation bracket 2041 and a liquid isolation chamber 2050 defined by a liquid isolation wall 2048. The irrigation chamber 2042 communicates with the liquid isolation chamber 2050. As shown in FIG4 , the irrigation chamber 2042 is connected to an irrigation fluid source 602 (e.g., saline, glucose solution, anticoagulant, or any combination thereof) via an irrigation fluid inlet 2043. The irrigation fluid enters the irrigation chamber 2042 through the irrigation fluid inlet 2043, then fills the accommodating chamber 2049. The irrigation fluid then enters the proximal end of the catheter 201, which is connected to the irrigation bracket 2041, and flows through the catheter 201 toward the distal end. During this process, the drive shaft 202 is lubricated. Furthermore, the flexible shaft 2021 is a braided structure, allowing liquid to penetrate the flexible shaft. In this way, the flushing liquid flowing out of the flexible shaft 2021 flushes the proximal bearing 208 and flows out from the gap between the proximal bearing 208 and the hard shaft 2022, thereby lubricating and cooling the proximal bearing 208. The flushing liquid flowing forward in the flexible shaft 2021 enters the hard shaft 2022 and flows out from the distal end of the hard shaft 2022. Under the blockage of the seal 213 disposed in the distal bearing chamber 207 and located far from the distal end of the hard shaft 2022, the flushing liquid flows out in the opposite direction and flows out from the gap between the hard shaft 2022 and the distal bearing 209, thereby lubricating and cooling the distal bearing 209.

[0051] As shown in Figure 4, to address the issue of high flushing fluid temperatures caused by the high-speed rotation of rotor 2046, coupling housing 2045 is further provided with a flushing fluid outlet 246 communicating with accommodating chamber 2049. Flushing fluid outlet 246 is specifically communicated with liquid isolation wall 2048. Catheter pump 100 includes a cooling circulation module 500 that allows the majority of flushing fluid to circulate outside the body, and a pressure maintenance module 600 that maintains flushing fluid pressure within the cooling circulation loop.

[0052] The cooling circulation module 500 includes a flushing liquid inlet pipe 501 connected to the flushing liquid inlet 2043 and a flushing liquid outlet pipe 502 connected to the flushing liquid outlet 246. The flushing liquid outlet pipe 502 is connected to the flushing liquid inlet pipe 501, and the two together with the accommodating chamber 2049 form a cooling circulation loop. The cooling circulation loop is equipped with a circulation drive 503 to drive the flushing liquid flow.

[0053] Pressure maintenance module 600 is connected to the cooling loop, maintaining the flushing fluid pressure within the cooling loop above the ambient pressure of pump head 205 during operation. This allows some of the flushing fluid in the cooling loop to enter the human body via conduit 201, cooling and lubricating the rotating components of working assembly 200. Simultaneously, driven by circulation drive 503, the flushing fluid continuously circulates within the cooling loop, removing the high temperature of the flushing fluid caused by the high-speed rotation of rotor 2046 and cooling the flushing fluid.

[0054] During operation of the catheter pump 1000, the front end of the pump head 205 (blood inlet 2051a) is inserted into the left ventricle, while the rear end (blood outlet 2051b) is located in the aorta. Furthermore, as the impeller 2052 rotates to pump blood, the distal end of the catheter 201 is placed in a positive blood pressure zone. Therefore, the ambient pressure of the pump head 205 during operation includes ventricular pressure, aortic pressure, and positive blood pressure. The resistance to flushing fluid entering the catheter 201 is greater than that experienced when exiting the flushing fluid outlet 246. This means that the flushing fluid must overcome this ambient pressure to enter the body through the catheter 201.

[0055] In addition, when the first portion of the flushing liquid flows forward from the catheter 201 to the proximal bearing 208, it needs to pass through the bearing gap and continue to flow forward. The bearing gap is specifically the gap between the outer wall of the hard shaft 2022 and the inner wall of the proximal bearing 208, and the gap between the outer wall of the hard shaft 2022 and the inner wall of the distal bearing 209. The first portion of the flushing liquid will encounter flow resistance at the bearing gap when flowing forward, and the flow resistance is inversely correlated with the size of the bearing gap. That is, the larger the bearing gap, the smaller the flow resistance of the flushing liquid. Conversely, the smaller the bearing gap, the greater the flow resistance of the flushing liquid. The flow resistance caused by the bearing gap also constitutes at least a part of the above-mentioned ambient pressure.

[0056] Furthermore, when the first portion of the flushing liquid flows forward in the catheter 201 and in the driving shaft 202 , there will also be flow resistance, which also constitutes at least a part of the above-mentioned ambient pressure.

[0057] To avoid discomfort to the human body, the amount of flushing fluid entering the body through catheter 201 should be limited and should be less than the amount flowing out of flushing fluid outlet 246. Based on the above, the flushing fluid pressure in the cooling loop is maintained by pressure maintenance module 600 to be greater than the ambient pressure of pump head 205 during operation, which is why the flushing fluid can enter catheter 201, which has greater resistance. Therefore, by controlling the flushing fluid pressure in the cooling loop through pressure maintenance module 600, the flushing fluid can achieve the aforementioned flow distribution.

[0058] Although the amount of flushing fluid required to enter the human body through catheter 201 varies in different clinical situations, in all scenarios, the amount of flushing fluid entering the human body through catheter 201 is generally much smaller than the amount flowing out of flushing fluid outlet 246. Therefore, the flushing fluid pressure in the cooling circulation loop is controlled by pressure maintenance module 600 to be slightly greater than the ambient pressure of pump head 205 during operation.

[0059] As shown in Figures 3 and 4 , rotor shaft 2047 has a channel 2053 extending axially therethrough, connecting flushing chamber 2042 and liquid isolation chamber 2050 via channel 2053 (the proximal end of channel 2053 is located within flushing chamber 2042, and the distal end is located within liquid isolation chamber 2050). Conduit 202 and flushing liquid inlet 2043 are connected to flushing chamber 2042, while flushing liquid outlet 2046 is connected to liquid isolation chamber 2050. Thus, flushing liquid entering flushing chamber 2042 flows backward through channel 2053 to liquid isolation chamber 2050, ultimately exiting through flushing liquid outlet 2046, enabling continuous circulation and cooling of rotor 2046.

[0060] A first bearing 235 is located within the accommodating chamber 2049, providing rotational support for the distal end of the rotor shaft 2047. The first bearing 235 partially isolates the flushing chamber 2042 from the liquid isolation chamber 2050. A flushing liquid inlet 2043 and a flushing liquid outlet 2046 are located on either side of the bearing 235. The liquid isolation provided by the first bearing 235 prevents flushing liquid entering the flushing chamber 2043 from flowing directly toward the flushing liquid outlet 2046. Instead, the flushing liquid is directed primarily backward through the channel 2053, thereby cooling the rotor 2046.

[0061] The diameter of rotor shaft 2047 is smaller than the inner diameter of first bearing 235 , leaving a first gap 2351 between the two. Flushing fluid can pass through first gap 2351 to lubricate first bearing 235 . The cross-sectional area of ​​first gap 2351 is smaller than that of channel 2053 . Therefore, flushing fluid primarily flows backward through channel 2053 , which has a larger cross-sectional area, ensuring sufficient flushing fluid flow for circulating cooling.

[0062] A second bearing 236 is also located within the accommodating cavity 2049 for rotatably supporting the proximal end of the rotor shaft 2047. Located proximal to the first bearing 235, the second bearing 236 cooperates with the first bearing 235 to provide dual-end rotatable support for the rotor 2046, thereby maintaining the stability of the rotor 2046's rotation. Similarly, the diameter of the rotor shaft 2047 is smaller than the inner diameter of the second bearing 236, leaving a second gap 2362 between the two. Flushing fluid can pass through this gap to lubricate the second bearing 236.

[0063] The second bearing 236 is provided with a flow hole 2361 extending axially therethrough, and the cross-sectional area of ​​the flow hole 2361 is larger than the cross-sectional area of ​​the second gap 2362. This increases the channel area for the flushing liquid to flow back forward, reduces the flushing liquid resistance, and facilitates achieving a large circulation flow.

[0064] As shown in FIG4 , the pressure maintaining module 600 includes a flushing liquid source 602 connected to the cooling circulation loop through a replenishing line 601 , and a pump 603 provided on the replenishing line 601 for replenishing the flushing liquid provided by the flushing liquid source 602 into the cooling circulation loop.

[0065] In this embodiment, the flushing liquid consumed due to entering the conduit 201 is replenished by an additional liquid source, namely the flushing liquid source 602. The pressure of the flushing liquid in the cooling circulation loop is maintained by another driving structure, namely the pump 603. In this way, the flushing liquid circulation and the flushing liquid pressure maintenance are completed by the circulation drive 503 and the pump 603 respectively, and the pressure required for the flushing liquid circulation and the pressure required for the flushing liquid pressure maintenance are different (generally, the pressure required for the flushing liquid circulation is less than the pressure required for the flushing liquid pressure maintenance). Therefore, the flushing liquid circulation and the pressure maintenance are driven separately, which can simplify the control of the circulation drive 503 and the pump 603, and make the flushing liquid pressure control and the flushing liquid flow control more accurate.

[0066] To facilitate pipeline connection, the cooling circulation module 600 further includes a buffer container 504. The flushing liquid inlet pipe 501, the flushing liquid outlet pipe 502 and the replenishing pipe 603 are all connected to the buffer container 504. The pipes can be connected to the buffer container 504 using a Luer head, which is convenient for pipeline connection.

[0067] To further improve the accuracy of maintaining or controlling the flushing liquid pressure, the buffer container 504 must at least be able to withstand the pressure replenishment of the pressure maintenance module 600 without any volume change. Furthermore, the buffer container 504 is a solid tank with a high pressure resistance and a constant volume under normal pressure. Alternatively, in certain embodiments, the buffer container 504 can directly use a three-way connector, whose three ports are respectively connected to the flushing liquid inlet pipe 501, the flushing liquid outlet pipe 502, and the replenishment pipeline 603, and the internal chamber of the three-way connector is used to construct the above-mentioned chamber whose volume remains unchanged when under pressure. Therefore, using a three-way connector to construct the buffer container 504 greatly simplifies the flushing pipeline.

[0068] Practice has proven that by installing a constant-volume buffer container 504 within the cooling loop, the precision of maintaining or controlling flushing liquid pressure is significantly improved. This result is surprising because, prior to adopting this design, the flushing liquid inlet pipe 501, flushing liquid outlet pipe 502, and replenishment line 603 were connected using flexible joints. After multiple rounds of testing, R&D personnel consistently found it difficult to achieve stable and expected flushing liquid pressure control.

[0069] The inventor has tried to explore the reasons why this design causes the above effects, but it is still unclear. The possible principles are speculated as follows:

[0070] To facilitate clinical piping deployment and routing, the flushing fluid inlet pipe 501 and flushing fluid outlet pipe 502 that form the cooling circuit are typically flexible tubes. High flushing fluid pressure can cause the flexible tubes to expand in diameter, leading to changes in the cooling circuit's volume. If the cooling circuit's volume changes while the pressure maintenance module 600 continues to operate at its original state (e.g., pump speed), this can cause the flushing fluid pressure in the cooling circuit to fluctuate (or decrease), leading to instability in the amount of flushing fluid entering the catheter 201.

[0071] In contrast, a buffer container 504 with a constant volume is provided in the cooling circulation loop (the volume of the buffer container 504 constitutes a part of the cooling circulation loop). Although the diameter expansion of the flushing liquid inlet pipe 501 and the flushing liquid outlet pipe 502 will not be changed, the volume of the buffer container 504 is larger than that of the flushing liquid inlet pipe 501 and the flushing liquid outlet pipe 502, and the volume of the buffer container 504 is not easy to change. In this way, the volume change rate of the cooling circulation loop can be greatly reduced. In the embodiment shown in FIG4 , the pump 603 that maintains the pressure of the cooling circulation loop is connected to the buffer container 504 through the supplementary pipeline 601. In this way, the pumping pressure of the pump 603 acts directly on the buffer container 504, rather than on the flushing liquid inlet pipe 501 and the flushing liquid outlet pipe 502, which can also slow down the change in the diameter of the flushing liquid inlet pipe 501 and the flushing liquid outlet pipe 502 to a certain extent.

[0072] In summary, by providing a buffer container 504 with a constant volume in the cooling circulation loop, the problem of volume change in the cooling circulation loop is at least partially solved, thereby improving the accuracy of maintaining or controlling the flushing liquid pressure.

[0073] As shown in FIG4 , in one embodiment, circulation drive element 503 is a pump disposed on flushing liquid inlet pipe 501 and / or flushing liquid outlet pipe 502 and is different from pump 603 (for purposes of distinction, this pump is defined as the first pump, and pump 603 is defined as the second pump). Because pump control technology is relatively mature, using a pump as circulation drive element 503 simplifies control.

[0074] Research has found that when rotor 2046 rotates at high speed while immersed in irrigating fluid, bubbles are generated. These bubbles are likely caused by the release of gas originally dissolved in the irrigating fluid due to the agitation and temperature rise of rotor 2046. Clinically, these bubbles are undesirable for entry into the human body, so it is necessary to capture the generated bubbles.

[0075] In an optional embodiment, the cooling circuit is equipped with a bubble filter 258 (Filter Bubble) to filter or capture bubbles, preventing them from entering the human body through the catheter 201. Furthermore, the bubble filter 258 is located on the flushing liquid inlet tube 501. This design facilitates the placement of the bubble filter 258 and avoids interference with other structures.

[0076] Furthermore, bubbles are primarily generated within the liquid isolation chamber 2050. They then flow out with the flushing liquid through the flushing liquid outlet 246, circulate through the flushing liquid outlet pipe 502 and the flushing liquid inlet pipe 501, and then re-enter the flushing chamber 2042 through the flushing liquid inlet 2043. Thus, from the time bubbles are generated until they re-enter the flushing chamber 2042 through the flushing liquid inlet 2043, they do not enter the human body through the catheter 201. This means that as long as bubbles are removed before entering the flushing chamber 2042, they can be substantially prevented from entering the human body. Therefore, installing the bubble filter 258 on the flushing liquid inlet pipe 501 can achieve the aforementioned purpose.

[0077] The bubble filter 258 can be any suitable existing structure, such as a filter screen or a filter membrane, and this embodiment is not limited thereto. The filter screen or filter membrane is housed within a housing structure. To reduce the resistance of the filter screen or filter membrane to the flow of the flushing liquid, the flow area of ​​the filter screen or filter membrane can be maximized. The housing housing the filter screen or filter membrane can be a flat, expanded structure.

[0078] Practice has shown that the flushing solution of this embodiment can not only significantly reduce the high temperature of the flushing liquid, but also cool the drive assembly 100. Specifically, as shown in Figure 3, the motor shaft 1021 is provided with a rotating bracket 105, and the active component 103 is provided on the inner wall of the rotating bracket 105. A bearing chamber 109 is provided in the motor housing 101, and the bearing chamber 109 is connected to the motor 102 through a flange 111. The bearing chamber 109 is provided with a bearing 110 for rotatably supporting the rotating bracket 105. Therefore, the rotating components in the drive assembly 100, such as the motor 102, the active component 103 and the bearing 110, are the parts that generate more heat. In order to solve the heat dissipation problem of these high-heat-generating components, the motor 102 is in contact with the bearing chamber 109 through the flange 111. Thus, during operation, active member 103, rotating bracket 105, bearing 110, bearing chamber 109, flange 111, and motor 102 are connected and physically contacted. This physical contact forms a heat conduction path from motor 102, flange, bearing chamber 109, bearing 110, rotating bracket 105, to active member 103. This allows heat from the main heat-generating components of drive assembly 110—motor 102, bearing 110, and active member 103—to be carried away by the high-flow irrigation fluid circulating within drive catheter handle 204. This heat is further dissipated into the outside air as the irrigation fluid participates in extracorporeal circulation, thereby cooling these components. Active member 103 is the component closest to the irrigation fluid. Therefore, heat from active member 103 is transferred through liquid isolation wall 2048 to the irrigation fluid within liquid isolation chamber 2050, thereby being cooled and forming a relatively low temperature. This allows heat from other physically contacting components to be transferred to active member 103 and then transferred through liquid isolation wall 2048 to liquid isolation chamber 2050, thereby achieving a temperature reduction.

[0079] Since the main heat-generating components of the drive assembly 100 are cooled by the flushing fluid in the drive catheter handle 204, the drive assembly 100 can simplify the heat dissipation design. As shown in Figure 3, the motor housing 101 is made of plastic. Compared with a housing made of metal, the plastic motor housing 101 has lower cost, lighter weight, and better feel, but has a worse heat dissipation effect. Among them, a worse heat dissipation effect is actually better for clinical purposes. The reason is that the outer surface of the motor housing 101 is inevitably touched by the human body. If the motor housing 101 is made of a material with good thermal conductivity such as metal, when it comes into contact with a part of the human body, such as a hand, the heat will be quickly transferred to the human body, which may burn the part of the human body. On the contrary, under the same surface temperature, the plastic motor housing 101 will not cause harm even if it is touched by the human body due to its poor thermal conductivity.

[0080] It should be understood that the above description is intended to be illustrative and not limiting. Many embodiments and applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the appended claims and the full scope of equivalents to which such claims are entitled.

[0081] For the purpose of completeness, all articles and references, including the disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein from the preceding claims is not a disclaimer of such subject matter, nor should it be interpreted that the inventors did not consider such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A catheter pump comprising: motor; catheter; a drive shaft rotatably disposed in the conduit; The pump head comprises: a pump housing connected to the distal end of the catheter, and an impeller housed in the pump housing; the impeller is connected to the distal end of the drive shaft so as to be driven to rotate and pump blood; The drive catheter handle comprises: a coupling housing connected to the proximal end of the catheter and detachably connected to the motor, and a rotor driven by the motor; the proximal end of the drive shaft is connected to the rotor, and the coupling housing is formed with a housing for rotatably supporting the rotor; the catheter is in communication with the housing, and the coupling housing is provided with an irrigation liquid inlet and an irrigation liquid outlet in communication with the housing. A cooling circulation module includes: a flushing liquid inlet pipe connected to the flushing liquid inlet, and a flushing liquid outlet pipe connected to the flushing liquid outlet; the flushing liquid inlet pipe, the accommodating chamber, and the flushing liquid outlet pipe form a cooling circulation loop, and a first pump for driving the flushing liquid is provided on the cooling circulation loop; The pressure maintaining module includes: a flushing liquid source connected to the cooling circulation loop through a supplementary pipeline, and a second pump provided on the supplementary pipeline for replenishing the flushing liquid provided by the flushing liquid source into the cooling circulation loop. 2 . The catheter pump according to claim 1 , wherein the second pump is used to maintain the flushing liquid pressure in the cooling circulation loop greater than the ambient pressure of the pump head during operation.

3. The catheter pump according to claim 1 or 2, wherein a portion of the flushing liquid entering the accommodating chamber through the flushing liquid inlet enters the catheter and is completely discharged into the human body at the pump head, and the other portion passes through the rotor and is discharged from the flushing liquid outlet. 4 . The catheter pump according to claim 3 , wherein the amount of the flushing fluid entering the catheter is smaller than the amount of the flushing fluid discharged from the flushing fluid outlet.

5. The catheter pump as described in claim 1, the cooling circulation module also includes a cache container, the flushing liquid inlet pipe, the flushing liquid outlet pipe and the replenishing pipeline are all connected to the cache container; the cache container can at least withstand the pressure replenishment of the pressure maintaining module without volume change. The catheter pump according to claim 5 , wherein the buffer container comprises a solid tank or a three-way joint. The catheter pump according to claim 1 , wherein the cooling circulation loop is provided with a bubble filter. The catheter pump according to claim 7 , wherein the bubble filter is provided on the flushing liquid inlet tube.

9. The catheter pump according to claim 1, wherein the rotor comprises a rotor shaft connected to the proximal end of the drive shaft, the rotor shaft having a passage extending axially therethrough; the drive catheter handle further comprises a flushing bracket and a liquid isolation wall disposed within the coupling housing, the flushing bracket defining a flushing cavity, and the liquid isolation wall defining a liquid isolation cavity; The flushing chamber and the liquid isolation chamber are communicated through the channel; The conduit and the flushing liquid inlet are in communication with the flushing cavity, and the flushing liquid outlet is in communication with the liquid isolation cavity.

10. The catheter pump according to claim 9, wherein the motor drives an active member to transmit the rotational power of the motor to a driven member coupled to the active member, the liquid isolation wall is located between the active member and the driven member, and the heat of the active member is transferred to the flushing liquid in the liquid isolation chamber through the liquid isolation wall.

11. The catheter pump according to claim 10, wherein the motor shaft of the motor is connected to the rotating bracket, and the active component is arranged on the inner wall of the rotating bracket; the motor is housed in a motor housing, and a bearing chamber is provided in the motor housing, the bearing chamber is connected to the motor through a flange, and a bearing is provided in the bearing chamber for rotatably supporting the rotating bracket.

12. The catheter pump according to claim 10 or 11, wherein the motor housing is made of plastic.

13. The catheter pump according to claim 9, wherein a first bearing is provided in the accommodating chamber for rotatably supporting the distal end of the rotor shaft, the first bearing partially isolates the flushing chamber from the liquid isolation chamber, and the flushing liquid inlet and the flushing liquid outlet are located on both sides of the first bearing. The catheter pump according to claim 13 , wherein a first gap exists between the first bearing and the rotor shaft. The catheter pump according to claim 14 , wherein a cross-sectional area of ​​the first gap is smaller than a cross-sectional area of ​​the channel. 16 . The catheter pump according to claim 13 , wherein a second bearing for rotatably supporting the proximal end of the rotor shaft is provided in the accommodating cavity, and a second gap exists between the second bearing and the rotor shaft. 17 . The catheter pump according to claim 16 , wherein the second bearing is provided with a flow hole penetrating in the axial direction, and a cross-sectional area of ​​the flow hole is larger than a cross-sectional area of ​​the second gap.

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