A direct stream hydrodynamic catheter system is provided for the removal of thrombus, lesions and the like including provisions for the infusion of drugs, lysing fluids and the like into a blood vessel. Physician controlled powered direct fluid jet streams emanate from a fluid jet emanatory in the form of robust radially directed fluid jet streams to impinge upon and ablate difficult and strong thrombus and lesions within a blood vessel. Effluent aspiration is controlled by an exhaust regulator in the form of a roller pump, but effluent removal can be assistingly influenced by the fluid pressure associated with the radially directed fluid jet streams.