Thrombin generation and fibrin formation following injury to rabbit neointima. Studies of vessel wall reactivity and platelet survival.

Using platelets prelabeled with 51Cr, we have quantified the effect of injury to the neointima on platelet accumulation, thrombus formation at different times following injury, and the effect of injury to the neointima on platelet survival. Platelet accumulation on the neointima is largely determined by activation of coagulation and thrombus formation; this contrasts with platelet accumulation on the subendothelium where coagulation does not play a major role and where few thrombi form. Heparin treatment significantly inhibits platelet accumulation on the injured neointima but is without effect on platelet accumulation on the subendothelium. Like the subendothelium, the neointima rapidly becomes nonreactive to further platelet accumulation, and the platelets and platelet-fibrin thrombi are lost from the surface in the first few days after injury. Despite the formation of extensive platelet thrombi on the injured neointima, platelet survival is unaffected.