Apparatus and methods for controlled clot aspiration

A vacuum aspiration control system for use with a vacuum source and an aspiration catheter, said system comprising:

• a connecting tube configured to connect the vacuum source with an aspiration lumen in the aspiration catheter;
• an on-off valve configured to be operatively coupled to the connecting tube;
• a sensing unit configured to detect flow within the connecting tube and to produce a signal representative of such flow;
• and
• a controller connected to receive the signal representative of flow through the connecting tube and to open and close the on-off valve,
• wherein the controller is configured to automatically close the valve to stop flow through the connecting tube when the signal indicates the catheter is aspirating blood free of vessel-obstructing clot, and
• wherein the controller is configured to periodically open the valve to sample flow, and wherein the valve is closed again if unrestricted flow is detected and the valve is held open if unrestricted flow is not detected.

A vacuum aspiration method comprising:

• (a) engaging a distal end of an aspiration catheter against an occlusion in a blood vessel;
• (b) applying a vacuum through an aspiration lumen of the aspiration catheter using a vacuum source coupled to a proximal end of the aspiration lumen by a connecting tube, whereby portions of the occlusion are drawn into the aspiration lumen, through the connecting tube and into a collection receptacle by the vacuum source;
• (c) sensing flow through the connecting tube;
• (d) automatically closing a valve to stop flow through the connecting tube when the sensed flow is unrestricted while the vacuum source remains on;
• (e) periodically opening the valve for a time interval to sample flow;
• (f) based on the sampled flow, closing the valve if the sampled flow is unrestricted flow or holding the valve open if the sampled flow is not unrestricted flow;
• and
• (g) repeating steps (d) through (f) until a desired amount of clot has been aspirated.