Clot removal from a patient's vessel, such as an artery, are described using aspiration and hydraulic forces supporting the removal process. Hydraulic forces can be generated by occluding the vessel distal to the clot and delivering liquid between the clot and the occlusive device. The aspiration catheter is positioned proximal to the clot. Catheters designed to facilitate the delivery of hydraulic forces can be based on single lumen designs or dual lumen designs. The catheters may have a fixed internal wire, or in some embodiments the catheters can ride over a wire with a valve/seal positioned to restrict flow into or out from the guide lumen such that the guide lumen can further function for balloon inflation and/or for infusion of liquid.
