The disclosure provides an apparatus and methods for removing thrombosis in vessels. The apparatus includes a sheath catheter combined with an aspiration catheter. The sheath catheter includes a first sheath opening in a proximal end of the sheath catheter, a second sheath opening in a distal end of the sheath catheter, a first balloon disposed on an outer surface of the distal end of the sheath catheter, and a passageway extending between the first and second sheath openings. The aspiration catheter is configured to pass through the first and second sheath openings and the passageway of the sheath catheter. The aspiration catheter includes a second balloon, a plurality of infusion ports, and an aspiration port disposed on an outer surface of a distal portion of the aspiration catheter. A relative position between the sheath catheter and the aspiration catheter controls the number of unblocked infusion ports.
