DETERMINANTS OF INCREASED REGIONAL LEFT ATRIAL COAGULATION ACTIVITY IN PATIENTS WITH MITRAL-STENOSIS

Background Recent evidence suggests that regional left atrial coagulat ion activity may be increased in mitral stenosis and perhaps contribut e to the pathophysiology of left atrial thrombus. However, the relatio n of left atrial coagulation activity to factors that predispose to le ft atrial thrombus formation is unknown, and the relation between left atrial and systemic coagulation activities is unresolved. Methods and Results Left atrial and peripheral venous levels of the coagulation m arker prothrombin fragment 1+2 (F1+2) were measured in 32 patients wit h mitral stenosis with normal clotting times and no left atrial thromb us who were undergoing percutaneous balloon mitral valvuloplasty. Base line peripheral venous F1+2 levels, measured at the beginning of the v alvuloplasty procedure, did not differ from those of 30 age-matched co ntrol patients. Prevalvuloplasty left atrial F1+2 levels, obtained imm ediately after transseptal puncture, were similar to femoral venous le vels in patients without left atrial spontaneous echo contrast (LASEC) (0.81+/-0.32 versus 0.81+/-0.27 nmol/L, n=7) bur greater than femoral venous levels in patients with LASEC and either sinus rhythm (1.57+/- 0.86 versus 0.99+/-0.38 nmol/L, n=16, P<.001) or atrial fibrillation ( 1.52+/-0.69 versus 0.85+/-0.33 nmol/L, n=9, P<.003). Furthermore, LASE C emerged as the only significant predictor of increased regional left atrial coagulation activity (P=.005) on stepwise multivariate logisti c regression analysis. Conclusions Increased regional left atrial coag ulation activity in mitral stenosis occurs in the presence of LASEC, i s evident in either sinus rhythm or atrial fibrillation, and is associ ated with normal systemic coagulation activity.