Aortocoronary artery vein-graft disease: Experimental and clinical approach for the understanding of the role of platelets and platelet inhibitors

On the basis of our recent experimental studies in dogs and pigs and a prospective clinical study in 407 patients, we describe four consecutive phases of aortocornary artery bypass vein-graft disease. We focus on the role of platelets in its pathogenesis and of platelet inhibitor drugs in its prevention: (1) an early postoperative phase of platelet thrombotic occlusion, which is significantly prevented by platelet inhibitor therapy when started in the perioperative period; (2) an intermediate phase of platelet-related intimal hyperplasia, within the first postoperative year, which is not prevented with platelet inhibitor therapy; (3) a late phase of occlusion, towards the end of the first postoperative year, in which intimal hyperplasia or complicating platelet thrombi superimposed on the intimal hyperplasia may contribute to occlusion - platelet inhibitor therapy is of significant benefit in the prevention of the thrombotic type of occlusion; (4) a phase of atherosclerotic disease, after the first postoperative year, in which the role of platelets and of platelet inhibitor therapy is under investigation. Vein graft disease and occlusion rates vary widely according to time after operation and risk factors of occlusion. Currently, it appears that occlusion rates are decreasing, perhaps related to better surgical and technical experience.