Catheters for aspiration of thrombotic, atherosclerotic or other particulate embolic debris from a blood vessel. An elongate flexible aspiration tube has an aspiration lumen defined by a reinforced tube wall. A guidewire tube is secured alongside the aspiration tube extending proximally from a distal end thereof to define either over-the-wire or single operator catheter configurations. The portion of the aspiration tube alongside the guidewire tube has an oval transverse cross section with a minor axis extending transversely through the guidewire tube. The oval cross section of the aspiration tube improves the catheters efficient use of cross sectional space by making the overall catheter transverse cross section nearly equal in orthogonal dimensions. Methods of making aspiration catheters are also disclosed, including permanently deforming the portion of the aspiration tube into an oval transverse cross section.
