Background and aims of the study: Left atrial (LA) and/or left atrial appendage (LAA) thrombi are often found in patients with rheumatic mitral stenosis (MS). The fate of these thrombi on optimal oral anticoagulation, and the feasibility of balloon mitral valvulotomy (BMV) is not well established. The study aims were to assess the efficacy of oral anticoagulation in the resolution/organization of these thrombi, and the feasibility and safety of Inoue BMV in these patients.
Methods: All consecutive patients with severe MS and a mitral valve suitable for BMV, but found to have LA/LAA thrombus on transesophageal echocardiography (TEE) between January 1999 and January 2001 were included. Anticoagulation was carried out with oral nicoumalone; the INR was maintained at 2.5-3.5. Follow up TEE was performed at intervals of two months for a maximum of six months. BMV using the Inoue balloon technique was performed as soon as possible after resolution or organization of thrombus.
Results: Sixty-six patients with MS (41 females, 25 males, mean age 33.1+/-10.4 years) and LA thrombus on TEE were studied. Thrombi were categorized into three groups: type I, thrombi localized to LAA (n = 36; 54.6%); type II, LAA thrombi protruding just beyond the LAA mouth (n = 22; 33.3%); and type III, LAA thrombi extending into the LA cavity (n = 8; 12.1%). Mean thrombus size was 27.6+/-9.1 mm (range: 15-35 mm). Complete resolution was seen in 22 patients (33.3%), and organization in 38 (57.6%). No significant change was observed in six patients (9.1%). Resolution was most common in the first two months, and in type I thrombi (41.7%, 27.2% and 12.5% in type I, II and III thrombi, respectively). BMV was performed in 90.9% of patients, and was uneventful in all. BMV was performed in the presence of organized thrombus in 63% of patients.
Conclusion: Anticoagulant therapy is effective in resolution and/or organization of LA thrombi in patients with MS. Six months' duration of anticoagulation appears optimal. BMV using the Inoue balloon technique can be performed safely after resolution or organization of thrombus, with no additional risk of complication.