[Beta-thromboglobulin and platelet regeneration time in children with mitral valve prolapse]

We studied 12 children with echocardiographic evidence of mitral valve prolapse (MVP) in order to demonstrate platelet activation or consumption as risk for thromboembolism. Therefore, with a standard radioimmunoassay, we measured the plasma levels of Beta-thromboglobulin (BTG), a platelet-specific protein released during platelet release reaction. Platelet turn-over was evaluated by measuring the Platelet Regeneration Time (PRT) with a non-radioisotopic method. Blood samples for BTG assay were collected at rest and after exercise. BTG plasma levels obtained in children with MVP were significantly higher than in normal subjects (p less than 0.01), both at rest and after exercise. We found no difference in either group between BTG level at rest and after exercise. The TRP was within the normal range in all patients except 2, in whom TRP was slightly shorter. Increased BTG levels and normal TRP suggest that in our patients platelet activation, but not consumption, was increased. In children with MVP, periodic controls of platelet activation may be useful to detect an increased risk of thromboembolism.