Causative Factors for Thrombi Formation in Mitral Stenosis

Abstract

Causative factors for thrombi formation in left atria of 38 patients with mitral stenosis who underwent mitral valve surgery (open mitral commissurotomy or mitral valve replacement) alone or in combination with other procedures were studied. There were 9 cases of left atrial thrombosis (LAT). Left atrial diameter was increased in LAT(+) group (6.1±1.6cm) compared with LAT(-) group (4.6±0.7cm). There was significant difference in the left atrial diameter between the two groups of patients (p<0.01). Cardiac output was decreased in LAT(+) group (3.04±0.74l/min) compared with LAT(-) group (3.99±1.07l/min). Cardiac output of LAT (-) group was significantly larger than that of LAT(+) group (p<0.05). Mean transition time of blood through left atrium (MTT_LA) was calculated using left atrial volume and cardiac output. In LAT (+) group, MTT_LA was significantly increased (6.2±3.9sec) compared with LAT(-) group (2.9±1.6sec). It is considered that, in mitral stenosis, prolongation of MTT_LA is one of the risk factors for thrombi formation in the left atrium.