[Changes in operative risk and its predictive factors in coronary surgery]

The operative risk of coronary bypass surgery has been reported by many surgical groups. Although the 1970's were characterised by a progressive decline in this risk related to improved surgical techniques and myocardial protection, the following decade saw a new rise in operative mortality. In order to assess this problem, the authors undertook a review of 3,632 consecutive cases of coronary bypass surgery (without any other procedure) from 1982 to 1991. The operative risk increased from 2% in 1982 to 7.7% in 1989 and was related to an increase in patients' age, in left ventricular dysfunction and in the number of emergency and redux operation. The development of interventricular cardiology in the last few years (angioplasty for double or triple vessel disease, 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 1989 is due to better overall management (pre, per and postoperative), especially of the high risk patients (patients over 70 years of age, women, left ventricular dysfunction, left main coronary stenosis, emergencies, reoperation). Although many variables indicating extramortality were found to be statistically significant (p < 0.05) on univariate analysis, multivariate analysis by two year periods showed the following independent prognostic factors of operative mortality: persistence of the concept of "emergency surgery" throughout the period under study and, from 1986, the appearance of gender and NYHA Class; and, from 1988, the factor "reoperation" with different values of "p" according to the years under consideration.