Aortic Valve Replacement Using Local Myocardial Hypothermia

Abstract

This material comprises 100 cases of aortic valve replacement. Ninety-one of the valves were replaced with the Björk—Shiley tilting disc valve prosthesis and 9 with the Smeloff—Cutter ball valve. No coronary perfusion was used during surgery. The myocardium was protected by local myocardial hypothermia, achieved by an intracoronary infusion of Bretschneider's solution (+4°C) prior to surgery. A weak and flaccid heart without coronary perfusion cannulas facilitated the surgical procedure. Myocardial function was very good and the course of the patients excellent postoperatively. Seven percent of the patients were lost within one month after operation and late mortality was 13%. A comparison between clinical and haemodynamic findings obtained 2–3 months before and one year after surgery was made in 55 patients. A marked subjective improvement was seen in all but five patients. There was a significant increase of average physical working capacity and regression of ECG-signs of left ventricular hypertrophy and strain as well as of roentgenological heart size. Angina pectoris was present in only three patients postoperatively as compared with 23 before surgery. The improvement of physical working capacity was paralleled by a significant increase of cardiac output during exercise, caused by a rise of stroke volume, heart rate on maximal load tolerated remaining unchanged. Blood pressure reactions during work were normalized in patients with both pre-operative aortic stenosis and aortic insufficiency. A significant postoperative paravalvular leakage was rare in the present material.