Platelet survival time and thromboembolism in patients with mitral valve prolapse.

Thromboembolism (TE) occurs in about 20% of patients with rheumatic mitral valve disease, and platelet survival time in these patients has correlated with TE. In patients with mitral valve prolapse, TE appears to occur very infrequently. Platelet survival (autologous labeling with chromium-51) was performed in 26 patients with mitral prolapse. Five patients had a history of stroke, as well as normal cerebrovascular arteriography and shortened platelet survival (average half-time +/- SEM 2.3 +/- 0.18 days; normal half-time 3.7 +/- 0.03 days; n = 26; p less than 0.01). Platelet survival was shortened in seven of 21 patients without TE (33%) (3.3 +/- 0.06 days; p less than 0.01 vs patients with TE). In 138 patients with rheumatic heart disease, platelet survival was shortened in 40 of 41 (98%) with a history of TE (2.3 +/- 0.08 days) and in 76 of 97 (78%) without TE (2.9 +/- 0.07 days; p less than 0.001 vs patients with TE). In patients with mitral prolapse, sulfinpyrazone increased platelet survival (2.4 +/- 0.16 to 2.7 +/- 0.19 days; n = 7; p less than 0.05). Our results suggest that platelet survival time is shortened in patients with mitral prolapse and rheumatic heart disease who have had TE. Of those without TE there is an increased frequency of shortened platelet survival in patients with rheumatic heart disease (78%) compared with those with mitral prolapse (33%), consistent with the infrequency of TE in mitral prolapse.