Aspiration thrombectomy system and methods for thrombus removal with aspiration catheter
A clot removal system comprises a catheter, a vacuum source, and a controller. The catheter comprises a proximal end, a distal end, and controller operating parameters and defines a lumen configured to be filled with a liquid column having a proximal portion. The vacuum source is configured to supply vacuum. The controller is configured to carry out a control pattern of turning on and off the vacuum based upon the controller operating parameters and is configured to receive the controller operating parameters in an automatic response to the catheter being operatively connected to at least one of the vacuum source and the controller and, responsive to the connection, to carry out the control pattern to change a level of vacuum at the distal end of the catheter.
1. An aspiration thrombectomy system, comprising:
a catheter system including an aspiration catheter having a proximal portion, a distal end, and a lumen extending through the aspiration catheter;
a vacuum source fluidically coupled to the catheter system;
a vacuum valve connected between the vacuum source and the proximal portion of the aspiration catheter to control a vacuum flow in the catheter lumen;
a vent valve fluidically coupled to the proximal portion of the aspiration catheter, the vent valve being configured to control a flow of a vent fluid in the catheter lumen; and
a controller configured to cyclically open and close the vacuum valve and the vent valve in a predetermined repeated cycle based on a compliance of the catheter system such that a pressure pulse from a vent phase momentarily moves the thromboembolic material downstream in the distal direction and whereby a subsequent vacuum phase reverses the pressure pulse and draws the thromboembolic material back against the distal end of the aspiration catheter.
2. The system of claim 1 , further comprising a vent fluid source, and wherein:
the vent fluid source is configured to provide vent fluid at a pressure greater than atmospheric pressure; and
the controller is configured to cyclically open and close the vacuum valve and the vent valve to alternate between a negative pressure and a positive pressure at the distal end of the aspiration catheter during each cycle.
3. The system of claim 2 wherein the controller is configured to cyclically open and close the vacuum valve and the vent valve such that movement of the fluid column at the distal end of the aspiration catheter is limited to a positive amount of exit flow of less than 20 microliters before fluid is drawn back into the catheter lumen.
4. The system of claim 1 wherein the controller is configured to cyclically open and close the vacuum valve and the vent valve in a cycle comprising a vacuum-only state in which the vacuum valve is open and the vent valve is closed, an off-off state in which the vacuum valve is closed while the vent valve is closed for a controlled period of time, and a vent-only state in which the vacuum valve is closed and the vent valve is open.
5. The system of claim 4 wherein the vacuum-only state is 40-60% of the cycle, the vent-only state is approximately 20-25% of the cycle, and the off-off state is the remainder of the cycle.
6. The system of claim 1 wherein:
the controller is configured to cyclically open and close the vacuum valve and the vent valve in a cycle comprising a combination of a first off-off state in which the vacuum valve is closed while the vent valve is closed, a vacuum-only state in which the vacuum valve is open while the vent valve is closed, a second off-off state in which the vacuum valve is closed while the vent valve is closed, and a vent-only state in which the vacuum valve is closed while the vent valve is open; and
the cycle is repeated.
7. The system of claim 1 wherein the cycle is repeated at a frequency of 6 Hz to 16 Hz.
8. The system of claim 7 wherein a change in vacuum level at the distal end each cycle is at least approximately 15 inHg to 25 inHg in a time of not greater than 20 ms to 50 ms.
9. The system of claim 8 wherein the cycle is repeated at a frequency of 8 Hz to 12 Hz and during each cycle the pressure differential at the distal end of the aspiration catheter is at least approximately 20 inHg in a time of not greater than approximately 20 ms.
10. A method for removing thromboembolic material, comprising:
positioning the distal end of a catheter at least proximate to thromboembolic material in a blood vessel of a person, wherein the catheter has a proximal portion, a distal end and a lumen extending from the proximal portion to the distal end; and
controlling a vacuum valve fluidically coupled to a vacuum source and the catheter and a vent valve fluidically coupled to a vent fluid source and the catheter according to a predetermined cycle based on a compliance of the catheter such that a pressure pulse from a vent phase is reversed before the thromboembolic material moves uncontrollably off the distal end in the distal direction.
11. The method of claim 10 wherein:
the vent fluid source provides the vent fluid at a pressure greater than atmospheric pressure; and
controlling the vacuum valve and the vent valve comprises cyclically opening and closing the vacuum valve and the vent valve to alternate between a negative pressure and a positive pressure at the distal end of the catheter during each cycle.
12. The method of claim 11 wherein controlling the vacuum valve and the vent valve comprises limiting movement of a fluid column in the catheter lumen at the distal end of the catheter to a positive amount of exit flow within a within a specific range of volume of fluid that exits the distal end of the catheter.
13. The method of claim 12 wherein the range of volume is less than 20 microliters.
14. The method of claim 10 wherein controlling the vacuum valve and the vent valve comprises cyclically opening and closing the vacuum valve and the vent valve in a cycle comprising a vacuum-only state in which the vacuum valve is open and the vent valve is closed, an off-off state in which the vacuum valve is closed while the vent valve is closed for a controlled period of time, and a vent-only state in which the vacuum valve is closed and the vent valve is open.
15. The method of claim 14 wherein the vacuum-only state is 40-60% of the cycle, the vent-only state is approximately 20-22% of the cycle, and the off-off state is the remainder of the cycle.
16. The method of claim 10 wherein the controlling the vacuum valve and the vent valve comprises opening and closing the vacuum valve and the vent valve in cycles of approximately 6 Hz to approximately 16 Hz, wherein during each cycle a change in level of vacuum at the distal end of the catheter is at least approximately 15 inHg to 25 inHg in a time of not greater than approximately 20 ms to 50 ms.
17. The method of claim 10 , further comprising:
cyclically opening and closing the vacuum valve and the vent valve in a cycle including a combination of a first off-off state in which the vacuum valve is closed while the vent valve is closed, a vacuum-only state in which the vacuum valve is open while the vent valve is closed, a second off-off state in which the vacuum valve is closed while the vent valve is closed, and a vent-only state in which the vacuum valve is closed while the vent valve is open; and
repeating the cycle.
18. The method of claim 10 , further comprising:
sensing identification information from a sense part associated with the catheter, wherein the identification information includes configuration data of the catheter; and
controlling the vacuum valve and the vent valve according to the configuration information of the catheter.
19. The method of claim 18 , wherein the configuration information is based on the compliance of the catheter.
20. An aspiration thrombectomy system, comprising:
a catheter system including an aspiration catheter having a proximal portion, a distal end, and a lumen extending through the aspiration catheter;
a vacuum source fluidically coupled to the catheter system;
a vacuum valve connected between the vacuum source and the proximal portion of the aspiration catheter to control a vacuum flow in the catheter lumen;
a vent valve fluidically coupled to the proximal portion of the aspiration catheter, the vent valve being configured to control a flow of a vent fluid in the catheter lumen; and
a controller configured to cyclically open and close the vacuum valve and the vent valve in a predetermined repeated cycle based on a compliance of the catheter system such that a pressure pulse from a vent phase causes a small distal movement of the thromboembolic material and is then reversed by subsequent application of vacuum whereby the repeated cycle macerates the thromboembolic material at the distal end of the aspiration catheter.