Catheter pump and method for identifying whether catheter pump is inserted too deep into heart of patient

Abstract

The catheter pump comprises a motor, a blood flow channel connected to the far end of the motor and a sensor. The base, located at the near end, of the motor is connected with the catheter. The blood flow channel comprises a blood outlet located at the near end. A sensor head of the sensor is arranged on the base, and the distance between the sensor head and the blood outlet ranges from 15 mm to 25 mm.

Description

Technical Field

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

[0002] In the prior art, the proximal sensors of catheter pumps are arranged in two ways. One solution, represented by CN210698361U, WO2023104997A1, CN217286896U, CN116271494A, etc., which is also the current mainstream solution, places the proximal sensor head at the distal end of the bleeding port. Another solution, represented by CN116212224A, CN117504115A, etc., places the proximal sensor head at the proximal end of the bleeding port, specifically at the distal end of the motor housing. These two solutions have a common feature, that is, the proximal sensor heads are both arranged close to the bleeding port.

[0003] The proximal sensor head is arranged close to the bleeding port to facilitate detecting whether the catheter pump is inserted too deep into the heart. Taking left ventricular assist as an example, when the catheter pump is correctly positioned, the blood inlet is located in the left ventricle and the bleeding port is located in the aorta. Due to the pulsatility difference in the pressures of the left ventricle and the aorta, by observing the real-time waveform of the pressure measured by the sensor head at the bleeding port, it can be determined whether the catheter pump is abnormally positioned.

[0004] However, both of the above two solutions have some defects. Among them, in the first solution, the optical fiber of the sensor has to cross the strut of the bleeding port, and the strut is relatively thin (for example, 0.3 mm wide and 0.15 mm thick). It is necessary to set a groove for accommodating the optical fiber on the outer wall of the strut, and the fabrication of the bleeding port and the installation of the optical fiber are difficult. This challenge is more obvious when the outlet cage is of a kinked design (such as CN217286896U, CN219251400U), because the optical fiber is embedded in the strut groove of the outlet cage and must adapt to the kinked trend of the strut. And the optical fiber includes brittle glass elements, and the kinked trend will greatly increase the risk of its damage. Therefore, the assembly difficulty and the probability of optical fiber damage are greater. In the second solution, the thickness of the motor housing is relatively thin (for example, 0.25 mm thick), the internal space is limited, and it is not convenient for the assembly of the sensor. In addition, although the problems of assembly difficulty and optical fiber damage probability in the second solution are alleviated to a certain extent compared with the first solution, this method greatly increases the probability of the sensor head being in the blood pressure fluctuation area, resulting in poor accuracy and stability of the measured blood pressure. Summary of the Invention

[0005] The present invention provides a catheter pump that facilitates the installation of a proximal sensor and improves the accuracy and stability of blood pressure detection.

[0006] The catheter pump includes a motor, a blood flow channel connected to the distal end of the motor, and a proximal sensor. The motor is located at the proximal base and is connected to the distal end of the catheter. The blood flow channel includes a bleeding port at the proximal end and a blood inlet at the distal end. The sensor head of the proximal sensor is provided on the base, and the distance between the proximal sensor head and the bleeding port is between 15 mm and 25 mm.

[0007] The catheter pump further includes a distal sensor, and the distal sensor includes a distal sensor head disposed adjacent to the blood inlet. The proximal sensor is used to measure the pressure in the patient's blood vessel (such as the aorta AO), and the distal sensor is used to measure the pressure in the patient's ventricle (such as the left ventricle LV). The method for identifying whether the catheter pump is inserted too deeply into the patient's heart includes: receiving the measured pressure AOP in the blood vessel and the measured pressure LVP in the ventricle measured by the proximal sensor and the distal sensor, obtaining the pressure difference ΔP between the ventricle and the blood vessel based on the motor current I and the motor speed ω, determining the estimated pressure AOP' in the blood vessel based on the measured pressure LVP in the ventricle and the pressure difference ΔP, and determining whether the pump assembly is inserted too deeply into the patient's heart based on the comparison between the estimated pressure AOP' in the blood vessel and the measured pressure AOP in the blood vessel. Description of the Drawings

[0008] Figure 1 It is a schematic diagram of the catheter pump provided by the present invention when applied to left ventricular assistance;

[0009] Figure 2 is Figure 1 a cross-sectional view of the motor in

[0010] Figure 3 a schematic exploded view between the catheter, the base, and the bearing seat;

[0011] Figure 4 and Figure 5 is a perspective view of the base;

[0012] Figure 6 is a perspective sectional view of the base;

[0013] Figure 7 is a schematic diagram of the structure of the bearing seat;

[0014] Figure 8 is a flow field diagram of the bleeding port of the catheter pump;

[0015] Figure 9 is a force-displacement curve of the pull-off test between the catheter and the base;

[0016] Figure 10 is a schematic diagram of the failure situation of each specimen during the pull-off test of the catheter and the motor base in this embodiment;

[0017] Figure 11 is a flowchart of the method for identifying whether the catheter pump is abnormally positioned according to the embodiment of the present invention;

[0018] Figure 12 It is a corresponding relationship diagram of motor current and pressure difference at different motor speeds. Specific embodiments

[0019] The terms "proximal" and "distal" are relative to the doctor operating the catheter pump. "Proximal" refers to the part relatively closer to the doctor, and "distal" refers to the part relatively farther from the doctor. For example, the catheter is located at the proximal end of the pump assembly, and the pump assembly is located at the distal end of the catheter. It should be understood that these orientation terms are defined for convenience of description and are not restrictive and absolute.

[0020] As Figure 1 and Figure 2 shown, the catheter pump includes a catheter 60, a pump assembly 50 provided at the distal end of the catheter 60 and deliverable to the patient's heart by the catheter 60, and a controller 40 located outside the patient's body and used to control the pump assembly 50. The pump assembly 50 includes a motor 10, a blood flow channel 70 connected to the distal end of the motor 10, and an impeller (not shown in the figure) housed in the blood flow channel 70 and drivingly connected to the motor 10. The blood flow channel 70 includes an intubation 73, a bleeding window 71 and a blood inlet window 71 connected to the proximal and distal ends of the intubation 73, and a bleeding port 711 and a blood inlet port 721 are respectively provided on the bleeding windows 71 and 72. Taking the catheter pump 10 for left ventricular assistance as an example, the pump assembly 50 passes through the aortic valve AV into the left ventricle LV, so that the intubation 73 straddles the aortic valve AV, the blood inlet port 721 is located in the left ventricle LV, and the bleeding port 721 is located in the aorta AO. The impeller is driven by the motor 10 to rotate, so that blood is sucked into the blood flow channel 70 through the blood inlet port 721 and then pumped out through the bleeding port 721, realizing auxiliary heart pumping and reducing the heart load.

[0021] The use of the catheter pump for left ventricular assistance is only a feasible application scenario, and it can also be used for right ventricular assistance (the bleeding port 721 is located in the right ventricle and the blood inlet port 721 is located in the pulmonary artery) or kidney assistance. This embodiment does not limit this. The following mainly describes the catheter pump as the main scenario for left ventricular assistance, but based on the above description, the protection scope of this embodiment is not limited thereby.

[0022] The catheter pump further includes a proximal sensor 20 provided on the motor 10 and a distal sensor 30 provided on the blood inlet window 71 and adjacent to the blood inlet port 721. After the pump assembly 50 is correctly positioned, the sensor 30 is used to measure the actual pressure LVP in the position (left ventricle LV) where the blood inlet port 721 is located, and the sensor 20 is used to measure the actual pressure AOP in the position (aorta AO) where the bleeding port 721 is located.

[0023] A cable 80 is threaded through the catheter 60 for realizing the electrical and signal connection between the pump assembly 50 and the controller 40. As Figure 2As shown, cable 80 includes a wire 82 connected to the motor 10 (stator 15) for transmitting an electrical signal to drive the rotation of the motor 10. The cable 80 also includes sensor cables 83 and 84 connected to the sensor heads of sensors 20 and 30 for transmitting the pressure signals measured by the sensor heads of sensors 20 and 30 to the controller 40. The controller 40 stores the electrical signal for driving the motor 10 and the pressure signals measured by sensors 20 and 30 in the memory, and can associate the electrical signal and the pressure signals with time and display them on the display screen.

[0024] Sensors 20 and 30 can adopt any suitable existing structures, including but not limited to piezoelectric pressure sensors, piezoresistive pressure sensors, optical pressure sensors, etc., and this embodiment does not limit this. The corresponding sensor cables 83 and 84 for the above various types of pressure sensors are cables, cables, and optical fibers respectively. Below, the main description scenario is based on the sensor cables 83 and 84 being optical fibers, and the protection scope of this embodiment is not limited thereby.

[0025] As Figure 3 shown, the motor 10 includes a base 11 at the proximal end of its motor housing 13. The base 11 is connected to the distal end of the conduit 60, and the sensor head 21 of the sensor 20 is provided on the base 11. As Figure 3 shown, the pressure-sensitive surface 22 at the distal end of the sensor head 21 deflects in response to changes in blood pressure, thereby realizing the measurement of blood pressure.

[0026] As Figures 4 to 6 shown, the base 11 is generally in a rotary body structure and has a cavity axially penetrating through it. A first groove 111 is formed by recessing the outer wall of the base 11, and a first channel 112 is formed by penetrating the bottom wall of the groove 111. The channel 112 communicates the groove 111 with the internal cavity of the base 11. The sensor head 21 is inserted through the channel 112 and received in the groove 111. Among them, the proximal end of the sensor head 21 is located in the channel 112, and the distal end is located in the groove 111.

[0027] As Figure 6 shown, the channel 112 is a variable-inner-diameter structure, including a section with a smaller inner diameter at the proximal end and a section with a larger inner diameter at the distal end, so as to form a step 113 at the connection of the two sections for limiting the sensor head 21. During the process of inserting the sensor head 21 into the channel 112 from the outside, the step 113 can limit the insertion depth of the sensor head 21, realize the installation limit of the sensor head 21, and can further realize repeatable positioning during assembly, which is very important for developing algorithms based on measurement values. In addition, the variable-diameter channel 112 preferably matches the thicker sensor head 21 and the thinner optical fiber 84 to achieve better positioning of the sensor head 21 and smooth passing of the optical fiber 84.

[0028] AsFigure 3 As shown, the optical fiber 84 connected to the sensor head 21 penetrates into the base 11. Since the sensor head 21 is provided at the proximal end of the motor 10, after the optical fiber 84 is led out from the distal end of the conduit 60, it is connected to the sensor head 21 at the base 11 closest to it, without having to cross the motor 10. This greatly reduces the difficulty of threading the optical fiber 84 and shortens the length of the optical fiber 84, saving material costs. In addition, compared with the bleeding window 71 and the motor housing 13, the base 11 has a greater wall thickness and internal redundant space, which is more conducive to the installation of the sensor head 21 and the routing of the optical fiber 84. The redundant space is the remaining space after removing other necessary structures. Although the space of the motor housing 13 is the largest, after the stator 15, the rotor and the bearing 14 are accommodated therein, the remaining space available for sensor and optical fiber deployment is small.

[0029] Figure 8 It is a flow field diagram obtained by simulating the blood flowing out of the bleeding window 71. The proximal end of the base 11 is set as the coordinate origin, the abscissa x is the axial distance extending from this origin to the distal end, and the ordinate is the maximum shear stress WSS of the blood and the blood pressure. It is found that when x ≤ 15 mm and x ≥ 39 mm, the blood pressure fluctuates little and the maximum shear stress WSS received by the blood is low, and these regions with little blood pressure fluctuation are more suitable for the positioning of the sensor head 21. Therefore, setting the sensor head 21 on the base 11 of the motor 10 can avoid the blood flow disturbance at the bleeding port 711, which is beneficial to improving the detection accuracy and stability of the sensor 20 and reducing the damage to the blood.

[0030] The length of the motor 10 is configured such that the distance between the sensor head 21 and the bleeding port 721 is greater than 15 mm but less than 25 mm (at this time, the sensor head 21 or the base 11 is approximately located in the section between 5 mm and 15 mm as shown in Figure 8 ). For example, the distance between the two can be 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, etc., or it can also be a value that increases at intervals of 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm between 15 - 25 mm. As shown in Figure 8 It can be seen that the distance between the two is defined as the distance between the distal end of the sensor head 21 and the proximal end of the bleeding port 721. Among them, the distance between the two being greater than 15 mm is used to enable the sensor head 21 to avoid the blood pressure fluctuation area and improve the accuracy and stability of the sensor 20 for measuring blood pressure. And the distance between the two being less than 25 mm is used to reduce the length of the rigid section of the pump assembly 50 and improve the bendability of the pump assembly 50 to ensure that the pump assembly 50 can be smoothly inserted into the patient's heart.

[0031] The distance between the two can be further reduced to between 18 mm and 20 mm (at this time, the sensor head 21 or the base 11 is approximately located within the section between 10 mm and 12 mm as shown in Figure 8 ). It can be seen from Figure 8 that the maximum shear stress WSS and blood pressure fluctuations suffered by the blood within this section are further reduced, and the beneficial effects of the detection accuracy and stability of the sensor 20 and the reduction of the rigid section length of the pump assembly 50 will be further highlighted.

[0032] As shown in Figure 3 , Figure 4 and Figure 6 , the inner wall of the base 11 corresponding to the groove 111 bulges inward to form a thickened portion 114, and the thickened portion 114 is used to make the groove 111 recess into it. The thickened portion 114 is formed by locally thickening the inner wall of the base 11. On the one hand, this can provide a setting space for the groove 111 and the channel 112, and on the other hand, it can also avoid compressing the internal space of the base 11 to the greatest extent, thus facilitating the threading of the cable 80.

[0033] The channel 112 runs through the bottom surface of the groove 111 and the inner surface of the thickened portion 114 obliquely with respect to the axis, so as to define that the sensor head 21 inserted therein extends gradually outward and obliquely in the direction from near to far. The channel 112 is only axially inclined, but not circumferentially inclined, which is manifested as the opening 1122 formed by the channel 112 on the bottom wall of the groove 111 being circumferentially aligned with the opening 1121 formed by it on the surface of the thickened portion 114 (that is, the two are in the same diameter direction, or the connection line between the two passes through the center of the cross-section of the base 11), but the opening 1122 is located radially outside the opening 1121.

[0034] The inclined channel 112 can enable the sensor head 21 to fully contact the blood, thus being beneficial to sensing the blood pressure. Moreover, it can also shorten the axial length of the sensor head 21, making the overall structure of the pump assembly 50 more compact. In addition, the inclined channel 112 transforms the originally axially extending optical fiber 84 into an inclined extension at an angle with the axis, which is beneficial to the optical fiber 84 entering the channel 112 from the base 11, ensuring that the optical fiber 84 does not exceed its minimum bending radius and preventing the glass element of the optical fiber 84 from being damaged due to excessive bending. Further, an adhesive material 18 for fixing the sensor head 21 is provided in the groove 111, and the sensor head 21 is inclined in the groove 111, which is beneficial to increasing the contact area between the sensor head 21 and the adhesive material 18 and improving the fixing effect of the sensor head 21.

[0035] As shown in Figure 6As shown, the proximal end of the groove 111 is deep and the distal end is shallow, including a proximal region 1111, a distal region 1112, and a transition region 1113 connecting the proximal region 1111 and the distal region 1112. The bottom surfaces of the regions 1111 and 1112 are planes with unchanged potential energy, but the depth of the proximal region 1111 is greater than that of the distal region 1112. The bottom surface of the transition region 1113 is a ramp surface, and its depth gradually decreases from near to far. Among them, the deeper proximal region 1111 can increase the accommodation capacity of the adhesive material 18 and improve the fixing strength of the sensor head 21. The shallower distal region 1112 can support the distal end of the inclined sensor head 21, prevent the distal end of the sensor head 21 from forming a cantilever structure, and prevent the sensor head 21 from shaking and increasing the risk of damage.

[0036] A step 113 is formed on the inner wall of the channel 112 corresponding to the proximal region 1111, so that the proximal end of the sensor head 21 is located in the proximal region 1111 with a deeper depth and a larger capacity of the adhesive material 18, improving the fixing strength of the sensor head 21. The length of the distal region 1112 is greater than that of the proximal region 1111, ensuring that the distal region 1112 has sufficient support length and improving the distal support effect of the sensor head 21.

[0037] As Figures 3 to 6 shown, the proximal part of the channel 112 obliquely penetrates the wall of the proximal region 1111, and the distal part obliquely passes through the transition region 3111 and then penetrates the bottom surface of the distal region 1112, so that the channel 112 forms an opening 1122 on the bottom wall of the groove 111, and further exposes the outer wall of the distal part of the sensor head 21 into the groove 111, enabling the adhesive material 18 to contact the sensor head 21 more fully and enhancing the fixing strength of the sensor head 21 in the groove 111.

[0038] The sensor 30 includes a distal sensor head (not shown in the figure) disposed adjacent to the blood inlet 721 and an optical fiber 83 connected to the distal sensor head. The base 11 is provided with a second channel 115 for the optical fiber 83 to pass through, and the channel 115 penetrates the distal end face of the base 11 and the inner surface of the thickened portion 114. As Figure 4 shown, taking the extension line of the channel 112 as the reference L1, in the direction from far to near, the channel 115 gradually approaches the channel 112, so that the opening 1151 formed by the channel 115 on the surface of the thickened portion 114 is closer to the reference L1 than the opening 1152 formed by it on the distal end face of the base 11. The trend of the channel 115 gradually approaching the channel 112 is caused by the combined inclination of its axial extension direction and circumferential extension direction, making the channel 115 inclined both axially and circumferentially. As Figure 4The extension line L2 shown. Based on the axis, the opening 1152 is located outside the opening 1151. Based on the circumferential direction, the opening 1152 is circumferentially offset from the opening 1151 (that is, the two are not in the same diametrical direction, or the connection line between the two deviates from the center of the cross-section of the base 11).

[0039] As Figure 1 and Figure 2 shown, the distal optical fiber 83 is led out from the blood inlet window 71, crosses the cannula 73 and is introduced into the motor 10 through the distal opening 131 of the motor housing 13 (runs between the motor housing 13 and the stator 15), and then forms a wire harness with the proximal optical fiber 84 and the motor wire 82 in the base 11 and is then threaded into the catheter 60. Therefore, the optical fiber 83 extends farther than the optical fiber 84, and both need to pass through the base 11. The channel 115 is inclined with respect to the circumferential and axial directions, so that the optical fiber 83 threaded therein is limited to the same inclined trend. In this way, the channel 115 gradually approaching the channel 112 is beneficial to the gathering of the optical fiber 83, the optical fiber 84, and the motor wire 82, and enables the optical fiber 83 to gradually transition from the relatively outer position of the motor housing 11 with a larger diameter to the central position of the catheter 60 with a smaller diameter, reducing the risk of the optical fiber 83 being bent and damaged when the radial position changes greatly.

[0040] Further, as described above, the groove 111 for receiving the sensor head 21 is recessed into the thickened portion 114. It is inclined in both the circumferential and axial directions, so that the extending direction of the channel 115 avoids the groove 111 and prevents the channel 115 from penetrating the groove 111, which is beneficial to reducing the manufacturing difficulty of the base 11 and improving the manufacturing yield of the base 11. And through this staggered design, it is possible to densely arrange the required structures on the base 11 with a small size without interference.

[0041] In addition, since the groove 111 communicates with the internal space of the base 11 through the channel 112, the adhesive material 18 filled in the groove 111 for fixing the sensor head 21 is also used to seal the channel 112 to prevent blood from entering the base 11 during the operation of the catheter pump. And the channel 115 avoiding interference with the groove 111 enables the adhesive material 18 to only seal the channel 112 to achieve the purpose of isolating blood from entering the motor 10, thereby reducing the difficulty of the adhesive material 18 in sealing blood.

[0042] As Figure 4As shown, channel 112 and channel 115 respectively form a first proximal opening 1121 and a second proximal opening 1151 on the inner surface of the thickened portion 114. The opening 1121 is roughly located in the middle region of the thickened portion 114, and the opening 1151 is roughly located in the distal region of the thickened portion 114, that is, the opening 1121 is located proximal to the opening 1151. The openings 1121 and 1151 are offset axially and circumferentially, and there is no overlapping area. In this way, the two openings 1121 and 1151 are close to each other but offset from each other. While facilitating the bundling of the wire harness, it avoids the entanglement of the optical fiber 83 with the optical fiber 84 before the optical fiber 83 is led out to the larger base 11. This not only facilitates the threading operation of the optical fibers 83 and 84, reduces the process difficulty, but also avoids the restraint of the axial movement due to the entanglement of the optical fibers 83 and 84 (when the catheter 60 is bent, the optical fibers 83 and 84 can release stress through axial movement. Limited axial movement will cause the stress on the optical fibers 83 and 84 to increase when the catheter 60 is bent, increasing the risk of fracture).

[0043] As Figure 3 and Figure 7 shown, the motor 10 further includes a bearing seat 12, a motor housing 13, a stator 15 provided in the motor housing 13, and a rotor driven by the stator 15 to rotate (including a rotor shaft 16 connected to the impeller and a magnet 17 provided outside the rotor shaft 16). The bearing seat 12 is connected between the base 11 and the motor housing 13, and a bearing 14 for supporting the rotor 16 is housed therein. The bearing seat 12 is provided with a recess 121 that cooperates with the thickened portion 114. The recess 121 can be understood as a receiving space for accommodating the distal end of the thickened portion 114. With the cooperation of the recess 121 and the thickened portion 114, the bearing seat 12 and the base 11 are circumferentially limited, which can increase the connection stability between the two. The distal end of the thickened portion 114 is close to the distal end of the base 11 or flush with the distal end of the base 11 to better fit with the recess 121.

[0044] The front and rear surfaces of the bearing seat 12 are penetrated to form wire passing holes 126 for allowing the wires 82 of multiple motors 10 to pass through. For example, there are three wire passing holes 126 corresponding to the three-phase motor 10. The circumferential inner walls between adjacent wire passing holes 126 protrude inward to form limiting portions 127 for limiting the wires 82. In this way, the adjacent wires 82 are separated by the limiting portions 127, avoiding the unexpected entanglement of the wires 82 immediately after being led out from the motor 10 (stator 15) and preventing the wires 82 from breaking off at the vulnerable connection points with the motor 10.

[0045] The bearing seat 12 is provided with a third channel 125 for the optical fiber 83 to pass through. The channel 125 is arranged corresponding to the recessed portion 121. After the recessed portion 121 is matched with the thickened portion 114, the distal opening 1152 of the channel 125 is aligned and communicated with the channel 115. In this way, the recessed portion 121 and the thickened portion 114 form an anti-misassembly mechanism. The cooperation between the two realizes the positioning and installation of the base 11 and the motor housing 13, and at the same time realizes the establishment of the threading channel for the optical fiber 83, reduces the alignment difficulty of the channels 115 and 125, and improves the assembly efficiency. Moreover, the cooperation between the two forms a high-strength mechanical anti-rotation effect on the bearing seat 12 and the base 11, preventing the low-strength fixation caused by other connection methods (such as bonding) between the two from causing circumferential relative rotation between the two, and avoiding the kinking and breaking of the optical fibers 83 and 84 and the motor wire 82 passing between the two.

[0046] As Figure 7 shown, the bearing seat 12 includes a proximal connection portion 122 for inserting into the distal end of the base 11, a distal connection portion 122 for inserting into the proximal end of the motor housing 13, and a flange portion 124 located between the two connection portions 122 and 122. The overall contours of the connection portions 122 and 122 and the flange portion 124 are cylindrical or disc-shaped, but the outer diameter of the flange portion 124 is larger than that of the connection portions 122 and 122. In this way, when the base 11 and the motor housing 13 are respectively connected to the connection portions 122 and 122, the flange portion 124 with a larger outer diameter plays a positioning role. By the front surface of the flange portion 124 abutting against the ends of the motor housing 13 and the base 11, the plug-in positioning of the base 11, the motor housing 13 and the bearing seat 12 is realized.

[0047] The recessed portion 121 is formed outside the connection portion 122, making the cross-sectional shape of the originally regular disc-shaped connection portion 122 have a partially concave discontinuous circle. The recessed portion 121 is arranged corresponding to one of the limiting portions 127, so as to utilize the limiting portion 127 with a larger radial thickness to provide space for the formation of the recessed portion 121, so as to improve the structural compactness and make it possible to form the required structure in the limited space of the bearing seat 12.

[0048] The channel 125 includes a first through hole 1251 penetrating the front and rear surfaces of the flange portion 124 and a second groove 1252 formed on the outer wall of the connection portion 122, and the two are axially aligned. The groove 1252 is in a straight strip shape to limit the optical fiber 83 embedded therein to be in a straight trend and avoid bending of the optical fiber 83. The through hole 1251 is aligned with the distal opening 1152 of the channel 115 after the recessed portion 121 is matched with the thickened portion 114, realizing the communication between the two.

[0049] As described in TW202508662A, a rigid structure (e.g., a motor) and a flexible structure (e.g., a cannula, a catheter) are prone to disconnection at the connection, which is mainly due to the different bendability of the two structures. The bending of the flexible structure will form a large stress at the connection with the rigid structure, and when the stress is greater than the connection force between the two, the connection will be disconnected.

[0050] CN118647433A provides a solution for achieving high-strength connection between a catheter and a motor by using a spiral nitinol coil, wherein the motor is similar to the catheter connection part of the base 11 of the present embodiment, including a tubular part for connecting to the catheter, the outer wall of the tubular part forming an external thread for threadably engaging the spiral nitinol coil component of the catheter.

[0051] Medical cannulas or catheters generally include an inner polymer layer, an outer polymer layer, and a metal reinforcement embedded between the two polymer layers, such as a spiral nitinol coil. Manufacturers generally do not provide medical cannulas or catheters with exposed metal reinforcements. CN118647433A uses the spiral metal reinforcement of the catheter to cooperate with the external thread of the tubular part. Although this can achieve the transition and high-strength connection between the catheter and the motor to a certain extent, it is necessary to remove the inner layer of polymer in advance on the basis of the complete catheter provided by the manufacturer to expose the nitinol coil, but this is obviously cumbersome. In addition, it is also required that the nitinol coil should not be damaged while removing the inner layer of polymer, which is also difficult.

[0052] In view of this, the present embodiment provides a high-strength and process-simplified connection solution between the conduit 60 and the motor base 11. Figure 2 , Figure 3 and Figure 6 As shown, the distal end of the catheter 60 is inserted into the proximal end of the base 11, and a second through hole 116 is provided on the side wall of the proximal end of the base 11, which penetrates in the radial direction. The through hole 116 and the outer wall of the distal end of the catheter 60 and the inner wall of the proximal end of the base 11 are filled with an adhesive material 18 to achieve a fixed connection between the two. The adhesive material 18 is a fluid viscous material such as epoxy resin glue, which can be cured by applying a curing condition such as heating to bond the catheter 60 to the base 11.

[0053] The proximal portion of the base 11 is also tubular or cylindrical, and its inner diameter is slightly larger than the outer diameter of the catheter 60 to achieve plugging of the two, and to form a gap between the two for accommodating the adhesive material 18. The adhesive material 18 is applied in advance to the distal outer wall of the catheter 60 and / or the proximal inner wall of the base 11, and then the two are plugged and assembled.

[0054] The through hole 116 can be formed on the base 11 by drilling, milling, laser engraving, etc., and this process does not involve damaging the conduit 60, which is obviously simple for the process. The setting of the through hole 116 increases the filling amount of the bonding material 18, and during the insertion and cooperation process of the conduit 60 and the base 11, the bonding material 18 extruded from the gap between the two can be supplemented, thereby improving the connection strength between the two.

[0055] A first annular groove 61 is formed by the depression of the inner wall of the proximal end of the base 11 and / or the outer wall of the distal end of the conduit 60. The annular groove 61 extends circumferentially and continuously and is axially aligned and communicated with the through hole 116. When pouring the bonding material 18 into the through hole 116, the bonding material 18 enters the annular groove 61 through the through hole 116, further increasing the filling amount of the bonding material 18, thereby improving the connection strength. In addition, the bonding material 18 in the annular groove 61 and the bonding material 18 in the through hole 116 communicated therewith are integrated to form a connection structure similar to a rivet. This structure is also a high-strength mechanical connection structure, greatly improving the connection strength between the two.

[0056] The circumferentially continuous annular groove 61 (including the annular groove 117 below) can be manufactured by a milling process, and the process is also simple. When the annular groove 61 is formed on the outer wall of the conduit 60, although it involves damaging the conduit 60, it should be noted that the thickness of the outer polymer layer of the conduit 60 is greater than that of the inner polymer layer (for example, the thickness of the outer polymer layer accounts for 50% - 80% of the wall thickness of the conduit 60). When forming a relatively shallow annular groove 61 on the outer wall of the conduit 60 (for example, the depth of the annular groove 61 is 20% - 30% of the wall thickness of the conduit 60), it involves damaging the outer polymer layer with a larger thickness and basically does not damage the intermediate metal reinforcement layer. In addition, in this embodiment, it is not expected that the metal reinforcement layer plays any role in assisting in improving the strength during the connection process of the two. Therefore, even if the metal reinforcement layer is damaged during the process of removing the outer polymer layer, it will not have an adverse effect on the final connection strength.

[0057] The axial length (groove width) of the annular groove 61 is greater than the aperture of the through hole 116, which is used to provide redundancy for the alignment of the annular groove 61 and the through hole 116, so that after the conduit 60 and the base 11 are inserted, there is always at least a partially overlapping area between the annular groove 61 and the through hole 116 to ensure the formation of the above rivet structure.

[0058] Furthermore, a circumferentially continuous second annular groove 117 is formed on the outer wall of the proximal end of the base 11, and the through hole 116 is formed at the bottom of the annular groove 117. The annular groove 117 enables multiple through holes 116 to be communicated, so that when applying the bonding material 18, the bonding material 18 can fill the through holes 116 at different positions in the circumferential direction through the annular groove 117. In addition, the annular groove 117 integrates the bonding material 18 in each through hole 116, further strengthening the above rivet connection strength.

[0059] The essence of bonding is the connection among three materials, and it is expected that the bonding material 18 will not separate from the other two materials. In this embodiment, the annular groove 117 mechanically fixes the bonding material 18 to the base 11, and the bonding material 18 hardly separates from the base 11. Similarly, the annular groove 61 mechanically fixes the bonding material 18 to the catheter 60 and hardly separates from it, so that the catheter 60 and the base 11 are strongly connected.

[0060] The bonding material 18 fills the annular groove 117 and is flush with the proximal outer wall of the base 11. This can be achieved by applying a slightly excessive amount of the bonding material 18 and mechanically grinding it after the bonding material 18 cures, avoiding depressions or protrusions at the position of the proximal end of the base 11 corresponding to the annular groove 117 to reduce blood shear.

[0061] A pull-off test was conducted on the catheter 60 and the motor 10 using the connection scheme of this embodiment, and the force-displacement curves of each test sample were obtained as Figure 9 shown. As can be seen from Figure 9 it, each specimen follows the changing trend of a typical stress-strain curve, including the elastic stage, the yield stage, the strengthening stage, and the local deformation stage. In the elastic stage, the specimen (specifically the catheter 60) undergoes elastic deformation, and the force-displacement relationship is linear. After the deformation exceeds the elastic limit, the specimen enters the yield stage. As the deformation increases, the force first decreases and then fluctuates slightly. After the deformation exceeds the yield limit, the specimen enters the strengthening stage. The specimen undergoes uniform plastic deformation, and with the strain hardening effect brought about by the plastic deformation, the strength of the material increases, causing the strain of the specimen to increase and the force to increase as well, but at this time the two are no longer in a linear relationship. After the deformation exceeds the plastic limit, the specimen begins to undergo non-uniform plastic deformation and forms a necking, the force decreases, and finally it fractures.

[0062] Since the base 11 is a rigid material relative to the catheter 60. Therefore, when the connection strength between the base 11 and the catheter 60 is high enough, Figure 9 the force-displacement curve shown is actually the stress-strain curve of the catheter 60. Thus, according to Figure 9 it, the tensile strength limit of the catheter 60 can be obtained, and by comparing which occurs first, the pull-off between the base 11 and the catheter 60 or the fracture of the catheter 60, the connection strength between the base 11 and the catheter 60 can be tested.

[0063] As Figure 10As shown above, during the pull-off test on each specimen, the failure mode of each specimen was recorded synchronously. As can be seen from the figure, the maximum fracture force (pull-off force) of each specimen is greater than 110 N, and even when the catheter 60 has fractured or necked down (necking down is a previous step of fracture, and continued stretching will develop into fracture), the catheter 60 still does not detach from the base 11. This shows that with the connection scheme of this embodiment, the connection strength between the base 11 and the catheter 60 is higher than the tensile strength limit of the material of the catheter 60 itself.

[0064] As described above, in the prior art, the proximal sensor is arranged close to the bleeding port, which can be used to detect whether the pump is inserted too deep into the patient's heart. Although in this embodiment, the sensor head 21 is arranged far from the bleeding port 711 to avoid the blood flow disturbance area, improving the detection accuracy and stability of the actual aortic pressure AOP, it results in that relying only on the actual aortic pressure AOP detected by the sensor head 21 and its waveform change, it is no longer possible to identify whether the catheter pump has been inserted too deep into the patient's heart.

[0065] For example, when the catheter pump moves forward unexpectedly until the middle of the motor 10 straddles the valve LV. At this time, the bleeding port 711 has entered the left ventricle LV, but the sensor head 21 is still located in the aorta AO. Obviously, the pressure measured by the sensor 20 at this time is still the actual aortic pressure AOP, and the pressure waveform displayed on the controller 40 hardly changes compared with the normal situation. This will cause a misjudgment for the doctor that the catheter pump is still correctly positioned, but in fact, at this time, the catheter pump has been inserted too deep into the patient's heart. In this article, the catheter pump being inserted too deep into the patient's heart means that the catheter pump moves forward so that the bleeding port 711 enters the left ventricle LV. At this time, both the blood inlet 721 and the bleeding port 711 of the pump assembly 50 are located in the left ventricle LV, that is, in the same pressure environment.

[0066] Therefore, an algorithm is needed to make up for the structural improvement scheme of the sensor head 21 in this embodiment to identify whether the pump assembly is abnormally positioned in the patient's heart.

[0067] Those skilled in the art should all know that the load overcome by the motor 10 of the pump assembly 50 is the pressure difference between the blood inlet 721 and the bleeding port 711 (when the blood inlet 721 and the bleeding port 711 are in the same pressure environment, theoretically the load that the motor needs to overcome is 0, and at this time the current I supplied to the motor will drop significantly). In this embodiment, the actual aortic pressure AOP measured by the sensor head 21 is not exactly equal to the pressure at the bleeding port 711 because the sensor head 21 and the bleeding port 711 are separated by the motor 10. Therefore, after the blood is pumped out from the bleeding port 711 and flows to the position where the sensor head 21 is located, there will be a pressure drop, which is caused by the length of the motor, so it is called the cross-motor pressure difference ΔPm.

[0068] The inventors of the present application have found that there is a correlation between the pressure difference ΔPm across the motor and the motor length. The pressure drop ΔPm caused by motors 10 of different lengths is generally relatively stable when the pump assembly 50 is correctly positioned (as will be introduced below, the relative stability of ΔPm is the fluctuation around the central value). Through in vitro bench tests, a catheter pump with motors of different lengths is simulated to pump blood in a patient's heart environment, and the pressures at the blood outlet 711 and the motor base 11 are measured respectively using two pressure sensors, and this correlation can be obtained (as shown in the following table) and stored in the controller 40. In actual use, since motors 10 of different lengths result in different distances between the sensor head 21 and the blood outlet 711, when the length of the motor 10 is known, the pressure difference ΔPm across the motor can be obtained by looking up the correlation table stored in the controller 40.

[0069] Therefore, when the pump assembly 50 is normally positioned, given the pressure difference ΔPm across the motor, the pressure Pout at the blood outlet 711 can be obtained using the actual aortic pressure AOP measured by the sensor head 21 (Pout = AOP + ΔPm). That is to say, by compensating the actual aortic pressure AOP measured by the sensor head 21 with the pressure difference ΔPm across the motor, the supplementary aortic pressure AOP” is obtained, which is used to reflect the pressure at the blood outlet of the motor load.

[0070] Table 1 Correlation table between motor length and pressure difference ΔPm across the motor

[0071] Motor length L Differential pressure across the motor ΔPm L1 ΔPm1 … … Ln ΔPm

[0072] When a distal sensor 30 is provided in the catheter pump, the pressure difference between the blood inlet 721 and the blood outlet 711 (hereinafter referred to as the pump load pressure difference) can be obtained based on the actual ventricular pressure LVP, motor current I, and motor speed ω measured by the sensor 30. As Figure 12 shown, according to the known embodiments provided by CN115814262A or CN117282016A, at a specific motor speed ω, the motor current I is proportional to the pump load pressure difference ΔP. The Figure 12 relationship described can also be obtained through in vitro bench tests, and a lookup table similar to the above table for the corresponding relationship between the motor current I and the pump load pressure difference ΔP at a specific motor speed ω is obtained and stored in the controller 40. Therefore, by determining the corresponding curve according to the current speed ω (ω1, ω2, ω3, ω4, …) of the motor 10 and combining the motor current I, the pump load pressure difference ΔP can be determined.

[0073] Since the actual ventricular pressure LVP is measured by the sensor 30 regardless of whether the pump assembly 50 is normally positioned or positioned too deep, the estimated pressure AOP' in the aorta (= LVP + ΔP) can be obtained based on the actual ventricular pressure LVP and the pump load pressure difference ΔP obtained based on the above solution.

[0074] When the pump assembly is normally positioned, the compensated pressure AOP" in the aorta obtained by using the cross-motor pressure difference ΔPm compensation scheme should be equal to the estimated pressure AOP' in the aorta obtained by the estimation scheme based on the actual ventricular pressure LVP, motor current I, and motor speed ω (AOP" = AOP'). Or, in other words, there is an offset value between the actual pressure AOP in the aorta measured by the sensor head 21 and the estimated pressure AOP' in the aorta, and this offset value is the cross-motor pressure difference ΔPm caused by the motor length (AOP' = AOP + ΔPm).

[0075] However, it should be noted that since the value of ΔPm is small and there are more or less disturbances in the blood flow inevitably (for example, this disturbance is affected by blood flow velocity, blood vessel diameter, etc.). Therefore, the offset value or cross-motor pressure difference ΔPm caused by the motor length has fluctuations centered around a certain fixed value, that is, ΔPm is between the minimum cross-motor pressure difference Min_ΔPm and the maximum cross-motor pressure difference Max_ΔPm, ΔPm ∈ [Min_ΔPm, Max_ΔPm]. It is possible that the difference between the actual pressure AOP in the aorta and the estimated pressure AOP' in the aorta takes a value within the range less than Max_ΔPm. Therefore, when the pump assembly 50 is normally positioned, AOP' - AOP < Max_ΔPm.

[0076] As Figure 11 shown, based on the above, the method for identifying whether the catheter pump is positioned too deep provided in this embodiment includes the following steps:

[0077] Step S10: Receive the actual pressure AOP in the blood vessel measured by the sensor 20.

[0078] Step S20: Receive the actual ventricular pressure LVP measured by the sensor 30.

[0079] Step S30: Based on the motor current I and the motor speed ω, obtain the pressure difference ΔP between the ventricle and the blood vessel, that is, the pressure difference between the blood inlet and the blood outlet referred to above, or the pump load pressure difference. The acquisition methods of the motor current I and the motor speed ω can refer to the description of CN118476788B.

[0080] Step S40: Based on the actual pressure LVP in the left ventricle LV and the pressure difference ΔP, determine the estimated pressure AOP' in the aorta (= LVP + ΔP).

[0081] Step S50: Based on the comparison between the estimated pressure AOP' in the aorta AO and the measured pressure AOP in the aorta AO, determine whether the pump assembly 50 is inserted too deeply into the patient's heart.

[0082] As described above, when AOP' - AOP < Max_ΔPm, the pump assembly is normally positioned. When AOP' - AOP ≥ Max_ΔPm, it indicates that the pump assembly 50 is inserted too deeply into the patient's heart. The specific reason is that, as described above, when the pump assembly 50 is inserted too deeply into the patient's heart, both the blood inlet 721 and the blood outlet 711 are located within the left ventricle LV. At this time, the motor 10 pumps blood under the same pressure environment, and the motor current I drops significantly. And according to Figure 12 the corresponding relationship shown, at a specific motor speed ω, the decrease in the motor current I means that the pump load pressure difference ΔP obtained from this relationship curve increases. While the distal sensor 30 still normally measures the actual pressure LVP in the ventricle, resulting in an increase (↑) in the estimated pressure AOP' in the aorta AO (= LVP + ΔP). Similarly, the proximal sensor 20 still normally measures the actual pressure AOP in the aorta AO, and its value remains unchanged, thereby causing the value of AOP' - AOP to increase, that is, to be greater than the maximum offset value Max_ΔPm under normal conditions.

[0083] When it is determined that the pump assembly 50 is normally positioned, no adjustment operation is required. Conversely, when the pump assembly 50 is inserted too deeply, such an operation is needed. As known above, the offset value ΔPm is caused by the motor length. Therefore, the difference between AOP' and AOP essentially reflects the excessive insertion amount of the pump assembly 50 in the patient's heart. Similarly, by obtaining the correlation correspondence table between the difference between AOP' and AOP and the excessive insertion amount through in vitro bench tests, the excessive insertion amount of the pump assembly 50 can be determined through the difference between AOP' and AOP. As Figure 10 shown, the outer surface of the catheter 60 is provided with scale lines. Since eliminating this excessive insertion amount is achieved by the doctor operating the catheter 60 to move outward, based on the determined excessive insertion amount, the outward movement adjustment amount of the catheter 60 (the two are equal) is determined, and the display screen of the controller 40 visualizes the outward movement adjustment amount of the catheter 60. The doctor, based on the recommended outward movement adjustment amount on the display screen, operates the catheter 60 to move outward and determines whether the outward movement distance has reached the recommended value by observing the scale lines on the catheter 60.

[0084] When it is determined that the pump assembly 50 is inserted too deeply, while the controller 40 displays the recommended outward movement adjustment amount of the catheter 60, it can send out early warning signals outward, including beeping alarms, text flashing, etc., to remind the doctor to intervene as early as possible.

[0085] The above are only the embodiments of the present application, and do not limit the scope of the present application accordingly. Any equivalent structural or equivalent process transformations made by using the specification and drawings of the present application, or directly or indirectly applied to other related technical fields, are similarly included in the protection scope of the present application.

Claims

1. A catheter pump, comprising: A catheter; A pump assembly provided at the distal end of the catheter and deliverable to a patient's heart by the catheter, comprising: a motor, a blood flow channel connected to the distal end of the motor, and an impeller received in the blood flow channel; the motor includes a base at the proximal end, and the base is connected to the distal end of the catheter; the blood flow channel includes a blood inlet and a blood outlet proximal to the blood inlet; the impeller is driven by the motor to rotate and pump blood from the blood inlet to the blood outlet; A proximal sensor, including a proximal sensor head; the proximal sensor head is provided on the base; Wherein, the length of the motor is configured such that the distance between the proximal sensor head and the blood outlet is between 15 mm and 25 mm; Preferably, the length of the motor is configured such that the distance between the proximal sensor head and the blood outlet is between 18 mm and 20 mm.

2. The catheter pump according to claim 1, wherein a first groove is formed by recessing the outer wall of the base, a first channel is formed by penetrating through the bottom wall of the first groove, and the proximal sensor head is inserted through the first channel and received in the first groove; Preferably, a thickened portion is formed by the inner wall of the base corresponding to the first groove protruding inward, and the thickened portion is configured to recess the first groove into it.

3. The catheter pump according to claim 2, wherein the first channel penetrates obliquely with respect to the axis through the bottom surface of the first groove and the inner surface of the thickened portion to define that the proximal sensor head inserted therein extends obliquely outward gradually in the direction from near to far.

4. The catheter pump according to claim 2, wherein a step is provided in the first channel for limiting the proximal sensor head; Preferably, the first groove includes a proximal region, a distal region, and a transition region connecting the proximal region and the distal region; the depth of the proximal region is greater than the depth of the distal region, and the depth of the transition region gradually decreases from near to far; Preferably, the length of the distal region is greater than the length of the proximal region, the proximal portion of the first channel penetrates obliquely through the wall of the proximal region, and the distal portion penetrates obliquely through the transition region and then through the bottom surface of the distal region; Preferably, the step is formed on the inner wall of the first channel corresponding to the proximal region.

5. The catheter pump according to claim 2, further comprising a distal sensor, the distal sensor includes a distal sensor head disposed adjacent to the blood inlet and a distal sensor cable connected to the distal sensor head; A second channel for the distal sensor cable to pass through is further provided on the base, and the second channel penetrates through the distal end face of the base and the inner surface of the thickened portion; Preferably, the second channel is inclined with respect to the axis and the circumferential direction such that in the direction from far to near, the second channel gradually approaches the first channel; Preferably, the first channel forms a first proximal opening on the inner surface of the thickened portion, and the second channel forms a second proximal opening on the inner surface of the thickened portion; the first proximal opening and the second proximal opening are offset in the axial and circumferential directions; Preferably, the motor includes a bearing housing connected between the base and the motor housing. The bearing housing is provided with a bearing for supporting the rotor of the motor; a recessed portion cooperating with the thickened portion is provided on the bearing housing.

6. The catheter pump according to claim 5, wherein a third passage for the distal sensor cable to pass through is provided on the bearing housing, and the third passage is configured to be aligned and communicated with the distal opening of the second passage when the recessed portion cooperates with the thickened portion; Preferably, the bearing housing includes: a proximal connecting portion for being inserted into the proximal end of the base, a distal connecting portion for being inserted into the proximal end of the motor housing, and a flange portion located between the proximal connecting portion and the distal connecting portion; the recessed portion is formed on the outer wall of the proximal connecting portion, and the third passage is provided corresponding to the recessed portion, including a first through hole penetrating the front and rear surfaces of the flange portion and a second groove formed on the outer wall of the distal connecting portion; Preferably, through holes for the wires of the motor to pass through are formed through the front and rear surfaces of the bearing housing, and the circumferential inner walls between adjacent through holes protrude inward to form a limiting portion for limiting the wires; Preferably, the recessed portion corresponds to one of the limiting portions.

7. The catheter pump according to claim 1, wherein the distal end of the catheter is inserted into the proximal end of the base, and a second through hole penetrating radially is provided on the proximal side wall of the base. An adhesive material is filled between the distal outer wall of the catheter and the proximal inner wall of the base within the second through hole; Preferably, a first annular groove continuous in the circumferential direction is recessed on the proximal inner wall of the base and / or the distal outer wall of the catheter, and the first annular groove is axially aligned with the second through hole; Preferably, the axial length of the first annular groove is greater than the aperture of the second through hole; Preferably, a second annular groove continuous in the circumferential direction is recessed inward on the proximal outer wall of the base, the second through hole is formed at the bottom of the second annular groove, and the adhesive material fills the second annular groove and is flush with the proximal outer wall of the base.

8. A method for identifying whether the catheter pump according to any one of claims 1-7 is inserted too deeply into a patient's heart. The catheter pump further includes a distal sensor, and the distal sensor includes a distal sensor head disposed adjacent to the blood inlet; the proximal sensor is used to measure the pressure in the blood vessel, and the distal sensor is used to measure the pressure in the ventricle; The method includes: Receiving the measured actual pressure AOP in the blood vessel measured by the proximal sensor; Receiving the measured actual pressure LVP in the ventricle measured by the distal sensor; Obtaining the motor current I and motor speed ω of the motor; Based on the motor current I and motor speed ω, obtaining the pressure difference ΔP between the ventricle and the blood vessel; Based on the measured actual pressure LVP in the ventricle and the pressure difference ΔP, determining the estimated pressure AOP' in the blood vessel; Based on the comparison between the estimated pressure AOP' in the blood vessel and the measured actual pressure AOP in the blood vessel, determining whether the pump assembly is inserted too deeply into the patient's heart.

9. For the method according to claim 8, when the difference between the estimated intravascular pressure AOP’ and the measured intravascular pressure AOP is greater than or equal to the maximum pressure offset value Max_ΔPm caused by the length of the motor, it is determined that the pump assembly is inserted too deeply into the patient's heart; Otherwise, it is determined that the pump assembly is correctly positioned in the patient's heart.

10. For the method according to claim 8, Obtain the excessive insertion amount of the pump assembly based on the difference; Determine the outward movement adjustment amount of the catheter based on the excessive insertion amount; Display the outward movement adjustment amount.

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