Clot disruption and dissolution are achieved using a catheter having the ability to infuse a thrombolytic agent, agitate the clot and agent, and aspirate broken-up clot from the blood vessel. A flow resistor in the catheter provides for infusion and/or aspiration to be concentrated primarily at a clot treatment area in a blood vessel while also providing optional infusion and/or aspiration distal to the treatment area. In some embodiments, infusion, aspiration and guidewire passage occur through a common lumen. The thrombolytic agent, such as tPA, streptokinase, or urokinase, is directly released into the clot at the point where the agitator is engaging the clot. In this way, the thrombolytic activity of the agent is enhanced and the dissolution of the clot is improved.