A suction catheter system is described with a suction extension interfaced with a guide catheter to form a continuous suction lumen extending through a portion of the guide catheter and through the suction extension. The suction extension can be positioned by tracking the suction nozzle through a vessel while moving a proximal portion of the suction extension within the lumen of the guide catheter. The suction extension can comprise a connecting section with a non-circular cross section for interfacing with the inner lumen of an engagement section of the guide catheter. The tubular body of the guide catheter can have a reduced diameter distal section the can be useful to restrain the movement of the suction extension. Proximal fittings attached to the guide catheter can facilitate safe removal of the catheter system from the patient by allowing for the removal of some or all of a tubular extension of the suction extension from the guide catheter behind a hemostatic seal. Pressure sensors connected to the proximal fittings can help to guide the procedures with reduced risk of embolizing thrombus.
