Patent Publication Number: US-2022218368-A1

Title: Thrombus removal device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present disclosure claims priority to U.S. Provisional Application Ser. No. 62/883,741 filed on Aug. 7, 2019, the entirety of which is hereby incorporated by reference herein for all purposes. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure relates to a thrombus removal device, which is used to efficiently remove thrombus from the body of a subject. 
     BACKGROUND OF THE INVENTION 
     Thrombosis is caused by abnormal coagulation of blood or debris that blocks the flow of blood in the vessel, which then causes hypoxia of adjacent tissues. Thrombosis is the main reason of ischemic stroke. Treatment of thrombosis focuses on removal of thrombus. Main stream treatment relies on thrombolytic medicines; however, the efficacy could vary from patient to patient. Interventional treatment is another option to remove thrombus in situ. Briefly, traditional interventional treatment introduces a device into the blood vessel to remove the thrombus mechanically. However, from time to time, the device might break the thrombus into pieces and larger pieces might cause thrombosis in other places of the blood vessel. 
     Another interventional treatment is related to the usage of negative pressure suction with a catheter. In a nutshell, the proximal end of the catheter is connected with a suction pump (or a syringe), and the distal end of the catheter is directed into a blood vessel. When the distal end of the catheter arrives the position of thrombus, the pump is used to suck the thrombus into the catheter by the production of the negative pressure so as to remove the thrombus from the patient&#39;s body. However, if the position of thrombus inside the patient&#39;s body is far away from the pump, the long catheter (i.e. long distance) will decrease the negative pressure created by the pump. Thus, the resulted negative pressure would be insufficient to remove the thrombus. Usually, the larger the inner diameter of the catheter, the stronger the pressure conserved. However, the larger catheter cannot be introduced into a small blood vessel and thus could be useless in many critical positions such as brain blood vessels. Another way to increase the negative pressure is to raise the suction power. However, as the maximum negative pressure created by the suction pump or syringe is 760 mmHg, it is limited to adjust or increase the pressure to over 760 mmHg. 
     In light of the foregoing, the field continuously needs a better solution to remove thrombus from the patient&#39;s body. 
     SUMMARY OF THE INVENTION 
     In order to achieve the aforesaid objective, the present disclosure provides a thrombus removal device in which a negative pressure is produced in a position close to thrombus to be removed in a blood vessel. 
     In an aspect of the present disclosure, a thrombus removal device comprising a catheter, at least one valve, and a shaft is provided. The catheter has a proximal end and a distal end, and defines a longitudinal axis. The at least one valve is positioned and movable longitudinally inside the catheter. The shaft is connected with the proximal end of the catheter, and comprises a driving mechanism and a wire. Wherein, the wire is connected to the driving mechanism at one end and connected to the at least one valve at an opposite end. The driving mechanism is configured to create a sudden movement of the at least one valve toward the proximal end of the catheter. 
     Preferably, the driving mechanism comprises a supporting rod and a spring disposed around the supporting rod. 
     Preferably, the shaft further comprises a body, and the spring and a part of the supporting rod are disposed in the body. 
     Preferably, one end of the spring connects to the supporting rod and an opposite end of the spring connects to the body of the shaft. 
     Preferably, the driving mechanism further comprises a releasing member for holding or releasing the supporting rod. 
     Preferably, the driving mechanism further comprises a chunk connected to the wire. 
     Preferably, the shaft further comprises an O-ring for sealing a space in the body. 
     Preferably, the shaft is connected with the catheter through a connector. 
     Preferably, the thrombus removal device comprises a plurality of the valves connected to each other in series and disposed in the catheter. 
     Preferably, the valves are connected to each other through the wire. 
     Preferably, the at least one valve is a ball or an extendable structure. 
     Preferably, the extendable structure is a balloon type or an umbrella type. 
     Preferably, the elasticity coefficient of the spring is 50-1000 N/m. 
     In the present disclosure, there are at least the following advantages: 
     1. In contrast to negative pressure created in the proximal end of the catheter far away from the thrombus to be removed in the prior art, the negative pressure of the present disclosure is created in the distal end of the catheter near the thrombus. 
     2. The effect of the thrombus removal device in the present disclosure will not be influenced by the length of the catheter, and/or the location of thrombus. 
     3. The thrombus removal device of the present disclosure can provide stable negative pressure so as to safely remove thrombus from the individual. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates the operational schematic diagrams of a thrombus removal device to remove thrombus from a blood vessel according to an embodiment of the present disclosure. 
         FIG. 2  illustrates a plurality of valves connected to each other in series according to an embodiment of the present disclosure. 
         FIG. 3  illustrates the schematic diagram of a shaft connected with the catheter according to an embodiment of the present disclosure. 
         FIG. 4  illustrates the schematic diagram of a chunk connected to the wire of a shaft according to an embodiment of the present disclosure. 
         FIG. 5  illustrates the schematic diagram of a shaft without/with an O-ring according to an embodiment of the present disclosure. 
         FIG. 6  illustrates the schematic diagram of a shaft connected with a catheter through a connector according to an embodiment of the present disclosure. 
         FIG. 7  illustrates the schematic diagrams of a valve located at the distal end of a catheter according to an embodiment of the present disclosure. 
         FIG. 8  illustrates the operational schematic diagrams of a thrombus removal device according to an embodiment of the present disclosure. 
         FIG. 9  illustrates the operational schematic diagrams of a valve to remove thrombus from a blood vessel according to an embodiment of the present disclosure. 
         FIG. 10  illustrates the schematic diagrams of a thrombus removal device of (a) a connector, (b) a pump, and (c) a syringe according to an embodiment of the present disclosure. 
         FIG. 11  illustrates the operational schematic diagrams of a valve of single-ball type or multi-ball type to remove thrombus according to an embodiment of the present disclosure. 
         FIG. 12  illustrates the operational schematic diagrams of a valve of single-balloon type or multi-balloon type to remove thrombus according to an embodiment of the present disclosure. 
         FIG. 13  illustrates the operational schematic diagrams of a valve with single-umbrella type or multi-umbrella type to remove thrombus according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Please refer to the following  FIG. 1 , which illustrates a working example of the thrombus removal device of the present disclosure. As shown in  FIG. 1 , the thrombus removal device  100  comprises a catheter  10 , a valve  20 , and a shaft  30   
     The catheter  10  comprises a distal end  11  and a proximal end  12 . The distal end  11  is to be introduced into a blood vessel  50  and eventually be positioned close to a thrombus to be removed (see part (a) of  FIG. 1 ). The proximal end  12 , on the other hand, is more likely to be positioned outside the body of the subject in need of thrombus removing. The proximal end  12  is connected to the shaft  30 . The operator, such as a medical practitioner, can control the movement of the catheter  10  through the shaft  30 . 
     The valve  20  can be any shape while in the working example of  FIG. 1 , the valve  20  is spherical. In an embodiment, the valve  20  has a shape corresponding to the inner wall of the catheter  10 . For example, the valve  20  is a sphere and has a diameter slightly shorter than the inner diameter of the catheter  10  so that the valve  20  is movable longitudinally inside the catheter  10  and is able to create a negative pressure while moving. In another embodiment, the thrombus removal device  100  comprises a plurality of valves  20 . For example, the plurality of valves  20  are linked with each other in series through a wire  34  axially, as shown in  FIG. 2 . In other specific embodiments, the valve  20  can be an extendable structure, such as a balloon type or an umbrella type. These embodiments are particularly favorable for multiple action in one operation. Further elaboration will be provided in following paragraphs. 
     Please refer to  FIGS. 1 and 3 . The shaft  30  comprises a body  31 , a supporting rod  32 , a spring  33 , and the wire  34 . The spring  33  has one end connected to the supporting rod  32  and the other end connected to the body  31 . In an embodiment, the elasticity coefficient of the spring  33  is 50-1000 N/m, preferably 100-600 N/m. Preferably, there are one or two indication lines  32   a  and/or  32   b  labeled on the supporting rod  32  to indicate a loaded position and/or a released position. The travel distance of the supporting rod  32  may range 2-20 cm, preferably 5-15 cm, wherein the travel distances means a distance from the released position to the loaded position. The end of the supporting rod  32  to be pressed may be formed of an elastic material, such as silicone or rubber, to reduce the impact as it is released from the loaded position. The body  31  is constructed for an operator to hold and has a releasing member  36 . The supporting rod  32 , the spring  33  and the releasing member  36  forms a driving mechanism for the valve  20 . The releasing member  36  holds the supporting rod  32  in position and releases the same while being pushed. The releasing member  36  may be formed of an elastic material, such as silicone or rubber, to reduce the vibration while triggering. 
     In an embodiment, the supporting rod  32  has a chuck  35  used to connect to the wire  34 . For example,  FIG. 4  shows the chuck  35  is connected to the wire  34  by clipping the wire  34 . The wire  34  and the chuck  35  can be any biomedical compatible materials, such as stainless. Refer to  FIG. 5 , it shows embodiments of the shaft  30  with or without the O-ring  37 . In an embodiment A′, the shaft  30  further comprises an O-ring  37  for sealing a space in the body  31  such that the negative pressure can be created and maintained more efficiently to increase suction force while the valve  20  is moving back to the proximal end  12  of the catheter  10 . The O-ring  37  also enhances the stabilization of the movement of the supporting rod  32  inside the body  31 . 
     Please refer to  FIG. 6 . The shaft  30  further comprises a connector  38 , which connects the catheter  10  with the body  31 . In this embodiment, the connector  38  is set in the front of the shaft  30  and accommodates the wire  34  to pass therethrough. 
     Operation of Disclosed Thrombus Removal Device 
     After the position of the thrombus of a patient is verified, a medical practitioner can remove the thrombus by using the thrombus removal device of the present disclosure. In a preferable embodiment, the thrombus removal device of the present disclosure can be used simultaneously with an imaging technology such as an X-ray and/or an ultrasound device. 
     Please refer back to  FIG. 1 . The medical practitioner can hold and operate the disclosed thrombus removal device  100  through the shaft  30 . First of all, a leading wire (i.e. guide wire; not shown in the figure) is introduced into the blood vessel  50  until the vicinity of the thrombus  40 . Then, the catheter  10  is extended alongside the leading wire until the distal end  11  of the catheter  10  adjacent to the thrombus  40 . The leading wire is drawn out after the catheter  10  is on position and the valve  20  is moved thereafter. The valve  20  is eventually positioned at the distal end  11  of the catheter  10  and basically at the edge thereof, as shown in  FIG. 7 . In other words, while the distal end  11  of the catheter  10  is adjacent to the thrombus  40  in the blood vessel  50 , the valve  20  is at the position of the catheter  10  closest to the thrombus  40 . 
     Then, please see part (b) of  FIG. 1 . After the catheter  10  and the valve  20  are at the desired position adjacent to thrombus  40  to be removed, the medical practitioner can push the releasing member  36  so as to release the position of the supporting rod  32 . The released supporting rod  32  would be pushed backward by the spring  33 . Consequently, a sudden movement of the valve  20  toward the proximal end  12  of the catheter  10  is initiated. In detail, please refer to  FIG. 8  and  FIG. 9  together. As shown in parts (a) and (b) of  FIG. 8 , the supporting rod  32  of the driving mechanism is pressed into a loaded status. Further refer to part (c) of  FIG. 8 . When the releasing member  36  is pressed, the supporting rod  32  will be released from the loaded status and quickly moved backward by the spring  33 . While the supporting rod  32  is moving backward, the wire  34  connected to the driving mechanism will be also pulled backward so that the valve  20  moves towards the proximal end  12  of the catheter  10 . As a result, at this moment, the pressure at the distal end  11  of the catheter  10  close to the thrombus  40  will be lower than the pressure at the vicinity of the thrombus  40  in the blood vessel  50 . That is, the negative pressure is produced at the distal end  11  of the catheter  10  so as to push or draw the thrombus  40  into the catheter  10  (see  FIG. 9 ). 
     Briefly, without being bound by any theory, the sudden movement of the valve  20  would create a negative pressure at the adjacent position of the thrombus  40 , thereby sucking the thrombus into the catheter  10 . The thrombus  40  will then be moved from the blood vessel  50 , transferred along the catheter  10 , and finally arrived outside of the patient&#39;s body. In an embodiment, a part or all of the connector  38  of the shaft  30  can be exchanged to connect with an external pump  60  or syringe  70 , as shown in parts (a) to (c) of  FIG. 10 . By this way, the thrombus  40  inside the catheter  10  could be easily and quickly took away from the catheter  10  by applying the pump  60  or syringe  70  with/without a tubing  61 . In another embodiment, as the thrombus  40  has been sucked into the catheter  10 , the medical practitioner can simply remove the catheter  10  together with the thrombus  40  so that the purpose of removing thrombus is met. 
       FIG. 11  illustrates the operational schematic diagrams of a valve of single-ball type or multi-ball type to remove thrombus according to an embodiment of the present disclosure. It further shows the corresponding movement of the ball-type valve  20  and the thrombus  40 . If the thrombus cannot be removed once, the medical practitioner can reset the supporting rod  32 , the wire  34 , the ball-type valve  20 , and the releasing member  36  back to an initial position and repeat the aforesaid action again without removing the catheter  10  from the patient&#39;s body. 
       FIG. 12  illustrates the operational schematic diagrams of a valve of single-balloon type or multi-balloon type to remove thrombus according to an embodiment of the present disclosure. In  FIG. 12 , the catheter  10  and the balloon-type valve  20  are positioned adjacent to the thrombus  40  in the blood vessel (Action i). Then, a sudden movement of the balloon-type valve  20  toward the proximal end  12  of the catheter  10  is initiated (Action ii). The sudden movement of the balloon-type valve  20  would create a negative pressure at the adjacent position of the thrombus  40 , thereby resulting in sucking the thrombus  40  into the catheter  10  (Actions ii and iii). In case that thrombus  40  is not fully removed or there is another thrombus needed to be removed, the balloon-type valve  20  can be shrunk to let the thrombus  40  pass (Action iv and v). Then, the shrunk valve  20  can be moved toward the next thrombus spot (Actions vi and vii) and inflated to repeat the aforesaid suction action again (Actions viii). 
       FIG. 13  illustrates the operational schematic diagrams of a valve of single-umbrella type or multi-umbrella type to remove thrombus according to an embodiment of the present disclosure. Likewise, the catheter  10  and the umbrella-type valve  20  are positioned adjacent to the thrombus  40  in the blood vessel (Action i). Then, the umbrella-type valve  20  is suddenly and quickly moved back to the proximal end  12  of the catheter  10  so as to produce a negative pressure at the distal end  11  of the catheter  10  adjacent to the thrombus  40 , causing the thrombus being sucked into the catheter  10  (Actions ii and iii). The umbrella-type valve  20  can be folded and extended repeatedly so that multiple actions of continuously removing thrombus  40  can be achieved in one operation (Actions iv to viii). In light of the foregoing, the thrombus removal device of the present disclosure is convenient to operate and provides better efficiency for removing thrombus. It also can be equipped for the conventional and clinically-used thrombus removal devices to improve its efficiency.