Angiographie Study of the Left Atrium in Mitral Stenosis

Systemic embolization of left atrial thrombi is a dread complication of mitral stenosis which is particularly likely to occur during and immediately following surgery on the mitral valve. The threat of embolization is confined to patients with atrial fibrillation. Taber and Lam (4) reported from this institution (The Henry Ford Hospital, Detroit) operative or postoperative embolization in only 2 patients of a group of 226 with normal sinus rhythm, compared to 29 operative or postoperative embolizations in 200 patients with atrial fibrillation. In 41 of the 200 patients preoperative embolization was present, and in 11 of these, emboli were noted in the operative or immediate postoperative period. The presence of an atrial thrombus is a contraindication for closed mitral commissurotomy, and unless all patients with fibrillation are to be operated upon by open heart technics the preoperative determination of the presence or absence of thrombi assumes importance. The angiographic demonstration of left atrial thrombi has been reported by Soloff and Zatuchni (3) in 1956, who found an incidence of 5 thrombi in 57 examinations, and also by Huston (2) in 1961. None of these investigators employed cinegraphic technics. We have made it a matter of routine to include angiography in the evaluation of the left atrium in mitral stenosis complicated by atrial fibrillation with or without a history of previous systemic embolization. A total of 97 angiographic studies have been performed, and in 61 patients subsequent valvular surgery was performed with exploration of the left atrium by closed or open technics. In 20 patients atrial thrombi were proved at surgery; none of these had embolization during or immediately following surgery. One from the group without known thrombi had an episode postoperatively which was clinically considered due to embolization. The valve in this instance was heavily calcified, and it was postulated that a piece of calcium had embolized from it. Technic The study is performed in the posterior anterior projection with the patient in the supine position. A No. 7 or No. 8 NIH catheter is positioned in the main pulmonary artery, and 40 ml. of 90 per cent Hypaque is delivered at a pressure of 600 lb. per square inch. The recording is made with a 35-mm. cinegraphic camera on a 9-in. intensifier with a pulsed current and a film speed of 30 frames per second. The filming is started prior to the injection and continued until the left atrium is emptied or the permissible time for a cinegraphic series is attained. Satisfactory opacification of the left atrium is usually obtained by injection of the contrast material into the main pulmonary artery. Injection into the right ventricle is less satisfactory because of the greater dilution effect and occasional incomplete emptying of the medium from the right ventricle before opacification of the left atrium.