Platelet Survival in Patients with Substitute Heart Valves

To determine the relation of thromboembolism to the presence of substitute heart valves platelet studies were performed in 55 patients. Average platelet survival was normal in patients with homograft valves and Beall prostheses, but was short in those with older prosthetic mitral valves. Short platelet survival time and the frequency of thromboembolism were significantly related. Thromboembolism had occurred in 62 per cent of patients with short survival but in only 9 per cent of those with normal survival, and average platelet survival was significantly shorter in 13 patients with thromboembolism than in 42 patients without thromboembolism. In postoperative patients with newer mitral valves, average platelet survival was abnormally short in those who had had thromboembolism before operation. Postoperative thromboembolism occurred in 30 per cent of these patients but in none of those without preoperative thromboembolism in whom meah platelet survival also was normal. Results demonstrate that platelet survival correlates with a history of thromboembolism in patients with substitute heart valves. (N Engl J Med 290:534–537, 1974)