Platelet activation in patients with mitral valve prolapse.

: An increased frequency of thromboembolic events in patients with mitral valve prolapse has been demonstrated. It has been suggested that this association may be related to increased systemic platelet activity. Beta-thromboglobulin (BTG) is a platelet specific protein secreted during the platelet release reaction, with BTG levels reflecting ongoing platelet activation. Plasma BTG levels were measured in 14 normal volunteers, 23 patients with mitral valve prolapse and nonthickened mitral leaflets (group 1) and 13 patients with mitral valve prolapse and thickened mitral leaflets (group 2). The BTG level was 8.1 +/- 4.6 ng/mL (mean +/- SD) in normal subjects, 9.6 +/- 5.5 ng/mL in the nonthickened mitral valve prolapse group and 10.0 +/- 5.7 ng/mL in thickened mitral valve prolapse group. There was no significant difference in the BTG levels between groups. Five patients with multiple valvular prolapse did not show elevation of BTG levels. The present study did not demonstrate increased BTG levels in neurologically asymptomatic mitral valve prolapse patients.