CORONARY-ARTERY SURGERY AFTER 70 YEARS OF AGE - ANALYSIS OF THE RISK-FACTORS OF OPERATIVE MORTALITY

The risk factors of operative mortality after coronary bypass surgery in patients over 70 years of age were studied in a consecutive series of 109 patients operated in our department between January 1990 and Ju ne 1992. The anginal pain was classified stage III or IV in 92 cases. Seventy-nine patients had triple vessel disease, 36 patients had left main stem stenosis and 57 had previous myocardial infarction. Twenty-s ix patients had ejection fractions of less than 50 % and 6 were less t han 30 %. The average number of bypass grafts was 2.35. Associated pro cedures included 9 endarteriectomies of the left main coronary, one en darteriectomy of the left anterior descending and right coronary arter ies, 2 myotomies involving the left anterior descending artery, 3 vent ricular remodeling procedures and 3 carotid endarteriectomies. Non-let hal postoperative complications were mainly pulmonary infections (19 c ases). The operative mortality was 5.1 % in the group with stable angi na. On the other hand, the mortality was 31.2 % in the group with unst able angina operated as an emergency or semi-emergency. The causes of death were mainly postoperative low output states (16 cases) and polya rteriopathy (mesenteric infarction: 6 cases). Although age was related to operative risk, the main prognostic factor was the preoperative ca rdiovascular status. The degree of emergency, unstable angina, left ma in coronary disease, duration of cardio-pulmonary bypass and the neces sity for inotropic or mechanical support in the postoperative phase we re significant risk factors for death. Sex, cardiovascular risk factor s, previous myocardial infarction and duration of aortic clamping were not correlated to mortality. A multivariate analysis only revealed 3 independant risk factors: the left ventricular ejection fraction, intr a-aortic balloon pumping, and duration of cardio-pulmonary bypass. The re were only two late deaths and 90 % of survivors were asymptomatic 6 months after surgery. The short-term vital prognosis and the severity of symptoms justify surgery despite the high mortality rate, especial ly in patients operated as an emergency. The operative risk could, how ever, be reduced by referral for surgery before the development of cri tical ischaemia resistant to medical therapy.