Hypercoagulability in patients with mitral stenosis -- from the viewpoint of the behavior of plasma antithrombin III and alpha2-plasmin inhibitor.
The concentration of plasma antithrombin III (AT III) and the biological activity of plasma alpha2-plasmin inhibitor (alpha 2-PI) were measured in cases of mitral stenosis (MS) and rheumatic heart disease (RHD) without MS. Cases of MS showed the findings of the low levels of plasma AT III and normal or a little higher levels of plasma alpha 2-PI, that was not recognized in RHD without MS. This finding was interpreted to be hypercoagulable because of the acceleration of coagulation and of little or slight retardation of fibrinolysis. Besides, the influence of atrial fibrillation and chronic congestive heart failure on hypercoagulability in cases of MS was detected clearly, but the influence of them in cases of non-RHD was obscure. As the results, the severer the degree of MS, the clearer the hypercoagulable state. Therefore, the prethrombotic state existed in cases of MS, combined with blood flow disturbance due to atrial fibrillation or chronic congestive heart failure, endocardial damage resulted from rheumatic fever in an early stage and hypercoagulable state mentioned above in the present study. There was no significant difference between cases with and without thrombi in the degree of hypercoagulability in subjects with MS shown in the present work. It was concluded that the consumption of AT III caused the low levels of it in cases of MS, and that the low production of AT III in the liver rather than consumption caused the low levels of it in cases of non-RHD.