An aspiration thrombectomy system for use with a vacuum source and an aspiration catheter includes an aspiration catheter, connection tubing configured to act as a common conduit for fluid communication between the aspiration catheter and a vacuum source, controllable valves operable to selectively open and close to control fluid flow, pressure sensors associated with the aspiration catheter or the connection tubing, and an automatic controller configured to operate the valves in a first operational state to generate fluid pressure changes, detect pressure levels in the system, wherein changes in the detected pressure levels are correlated with the generated fluid pressure changes, determine system states based on system state scores determined based on the detected pressure levels, the system state scores indicating a measure of occlusion in the aspiration catheter or the connection tubing, and operate the valves in a second operational state based on the determined system states.