Regional left atrial coagulation and fibrinolytic activities in patients with mitral stenosis.

Systemic thromboembolism is a major complication of mitral stenosis (MS), especially in those patients having atrial fibrillation (AF). Recent evidence has suggested that regional left atrial coagulation activity may be increased in MS and may contribute to the pathophysiology of left atrial thrombus. However, the relation of left atrial coagulation activity to factors that predispose to left atrial thrombus formation is unknown. Also, the relations between left atrial and systemic coagulation activity, fibrinolysis, and platelet activation remain unresolved. Left atrial and peripheral venous levels of fibrinogen, antithrombin III, factor VII and factor VIII for coagulation, D-dimer, tPA and PAI-I, plasmin and antiplasmin for fibrinolysis, and platelet factor 4 and vWF for platelet activation, and endothelial dysfunction were measured in 46 patients with MS and normal clotting times who were undergoing percutaneous mitral valvuloplasty. Left atrial tPA, plasmin, PAI-I, antiplasmin, PF4, and vWF levels exceeded the corresponding peripheral venous levels (P < 0.05) in patients with MS, being more significant in the AF subgroup. There were no significant differences between left atrial and peripheral venous levels of fibrinogen, D-dimer, factor VII, and factor VIII within the patient group (P > 0.05). The results suggest that there are significant variations in the indices of coagulation, fibrinolytic system and platelet activation, and endothelial dysfunction between left atrial and peripheral venous blood samples of patients with MS that may be due to limited spillover from the left atrium to the systemic circulation.