A dynamic aspiration method including engaging a distal end of an aspiration catheter against an occlusion in a blood vessel, 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, sensing flow through the connecting tube, and automatically generating pressure differentials when a clog or restricted flow is detected.