Abstract
(1) Changes in platelet count, platelet adhesiveness, activated partial thromboplastin time, one-stage prothrombin time, plasma coagulation factors VIII, VII-X, X, V, II (prothrombin), and I (fibrinogen), euglobulin lysis time, plasminogen level, antiplasmin and trypsin inhibitor activity of plasma were determined before and after the development of myocardial infarction in 3 cases.
(2) Before the onset of the infarction, platelet adhesiveness was increased, but fibrinolysis was not decreased. Factor VIII activity was increased in 1 case in which it was measured.
(3) Immediately after the onset of myocardial infarction, platelet adhesiveness was transitorily decreased in 2 cases, factor VIII activity was rapidly enhanced to an extraordinarily high level in I case. Levels of the other clotting factors varied, but a trend was for elevation of these factors. Regarding fibrinolysis, hyperfibrinolysis was present at that time, as indicated by shortened euglobulin lysis time and decreased antiplasmin activity. Subsequently, a marked increase in platelet adhesiveness and fibrinogen, normalization of factor VIII activity, a prolongation of euglobulin lysis time, and a significant increase in plasma trypsin inhibitor activity were found.
(4) The results obtained in the present investigation strongly suggest that increased platelet adhesiveness is of great importance concerning the etiology of coronary thrombosis. Decreased fibrinolysis was not demonstrated in our 3 cases just before the development of myocardial infarction.
