CHANGES IN OPERATIVE RISK OF CORONARY-BYP ASS SURGERY AND ITS PREDICTIVE FACTORS

The operative risk of coronary bypass surgery has been reported by man y surgical groups. Although the 1970's were characterised by a progres sive decline in this risk related to improved surgical techniques and myocardial protection, the following decade sawa new rise in operative mortality. In order to assess this problem, the authors undertook a r eview of 3 632 consecutive cases of coronary bypass surgery (without a ny other procedure) from 1982 to 1991. The operative risk increased fr om 2 % in 1982 to 7.7 % in 1989 and was related to an increase in pati ents' age, in left ventricular dysfunction and in the number of emerge ncy and redux operation. The development of interventricular cardiolog y in the last few years (angioplasty for double or triple vessel disea se, thrombolysis in the acute phase of myocardial infarction) has also increased the number of patients operated as emergencies with a high operative risk. The reduction of the operative risk observed since 198 9 is due to better overall management (pre, per and postoperative), es pecially of the high risk patients (patients over 70 years of age, wom en, left ventricular dysfunction, left main coronary stenosis, emergen cies, reoperation). Although many variables indicating extramortality were found to be statistically significant (p < 0.05) on univariate an alysis, multivariate analysis by two year periods showed the following independent prognostic factors of operative mortality : persistence o f the concept of ''emergency surgery'' throughout the period under stu dy and, from 1986, the appearance of gender and NYHA Class; and, from 1988, the factor ''reoperation'' with different values of ''p'' accord ing to the years under consideration.