A nonhuman primate vascular shunt model for thrombus generation.

A nonhuman primate model for thrombus generation was developed. Three different types of test devices constructed of polystyrene or polyethylene-Silastic were exposed to flowing blood in arterioarterial or arteriovenous vascular shunts in rhesus monkeys. The test device design included a simple tube, a vortical flow device, and a turbulent flow device. The amount of thrombus deposited within each individual test device after a 15-minute exposure to blood flowing through the shunt was determined gravimetrically. These studies indicate that a test device designed to include an area of vortical flow generated the greatest amount of thrombus. Test devices fabricated from polystyrene consistently generated larger thrombus deposits than did similar test devices fabricated from polyethylene-Silastic. Arteriovenous shunts proved superior to arterioarterial shunts in that flow was predictable in the former and unpredictable in the latter; venovenous shunts thrombosed quickly. Hematologic studies indicated a progressive fall in platelet count during the 4-hour test interval in all animals, whereas in only a few animals were there a shortening of partial thromboplastin time values, a fall in fibrinogen levels, and the appearance of fibrin degradation products. An optimal model for thrombus generation appears to include vortical flow test devices fabricated of polystyrene exposed to flowing blood in an arteriovenous shunt.