[Laboratory diagnosis of left atrial thrombi in patients with mitral stenosis].

Left atrial (LA) thrombi sometimes occur in patients with mitral stenosis (MS) and the systemic embolization due to thrombi causes a serious, occasionally fatal complication. Several clinical techniques have been used to estimate the presence of LA thrombi. However, the hitherto available methods, even an echocardiography which has been most widely used, still have some drawbacks, depending on the size and location of thrombi. The author measured D-dimer, fibrinopeptide A (FPA) and thrombin-antithrombin III complex (TAT) in the patients with MS and evaluated the diagnostic value of these molecular markers to estimate the presence of LA thrombi. Twenty six patients with MS who had undergone cardiac operation were studied. Atrial fibrillation was found in all the patients. Episode of obvious thromboembolic diseases is a criteria of exclusion. Blood was drawn from the brachial vein several days (3 +/- 1 days: mean +/- SD) before the operation. The presence or absence of thrombus was confirmed at the surgery in all the cases. 1) Both levels of D-dimer and TAT were significantly higher in the patients with thrombi than those in the patients without thrombus or those in normal controls (mean: 378, 93 and 64 ng/ml, respectively; p less than 0.01 for both and 9.1, 2.0 and 1.7 ng/ml, respectively; p less than 0.01 for both). However, levels of FPA were not significantly different among the three groups (mean: 7.9, 4.9 and 3.7 ng/ml, respectively; NS for both). 2) both levels of D-dimer and TAT were significantly correlated with the weights of LA thrombus (r = 0.87, p less than 0.01: r = 0.79, p less than 0.01, respectively). 3) LA thrombi (ca. greater than or equal to 2 g) were always confirmed at the surgery in the patients who had levels of D-dimer higher than 200 ng/ml and/or TAT higher than 4 ng/ml. The plasma levels of D-dimer and TAT were further followed after the surgery in the same 18 patients (8 patients who had thrombus, the rest who didn't). 1) In the patients who had thrombi, levels of D-dimer were significantly decreased after the surgery (mean: from 267 ng/ml to 73 ng/ml, p less than 0.05). Levels of TAT were slightly but not significantly decreased (mean: from 82 ng/ml to 76 ng/ml, NS).(ABSTRACT TRUNCATED AT 400 WORDS)