US Patent 7033336 Proximal catheter assembly having a relief valve

The present invention is directed to a proximal catheter assembly that is configured to facilitate natural or suction-assisted aspiration through a catheter lumen. The proximal catheter assembly comprises a relief valve configured to regulate the level of suction-assisted aspiration provided through the working lumen of the catheter. When the level of suction-assisted aspiration exceeds a predetermined threshold, the relief valve opens to allow fluid to be drawn from tubing coupled to the proximal catheter assembly, thereby mitigating the relatively high levels of aspiration imposed upon the working lumen and the patient's vessel.