Platelet Consumption in Cardiovascular Disease

Many tests have been devised to investigate the role of platelets in arterial or venous thromboembolism. The mechanisms of platelet reactivity that the tests have measured have been variable and the early studies have been of little value in determining the contribution of platelet consumption in thromboembolic diseases. More recently, tests of in vivo platelet release and of platelet survival and turnover have been introduced and thought to be of great potential in the investigation of thromboembolic disorders. However, the data published thus far using more tests are far from conclusive that platelet activation and consumption occurs in thromboembolic disorders associated with arteriosclerosis. It may be that they are neither sensitive nor specific enough to detect minor changes in platelet activation. There is, however, some consistency that in conditions involving the larger vessels, prosthetic surfaces, or in association with active and recurrent venous thromboembolism, platelet release and platelet consumption measured by platelet survival time may occur. In particular, the abnormal results are consistently found in acute and recurrent venous thromboembolism, cardiac valve replacement with the older prosthetic devices, and arteriosclerosis of the larger arteries with clinical episodes of thromboembolism. However, in coronary artery disease, cerebrovascular disease, and peripheral vascular disease, the data are inconclusive, probably because the tests lack sensitivity. In addition, the value of the tests in the management of patients with thromboembolic disorders appears to be limited.