Assessment of the impact of coronary artery surgery on mortality after recovery from myocardial infarction.

Death rates over a nine year period were studied in 1,232 survivors of myocardial infarction. From 1973 to 1981, the 29 to 365 day case fatality rate in 28 day survivors dropped from 13.3% to 3.2%. This down-trend in case fatality was highly significant, averaging 14.3% in each year. After adjustment for changes in age and severity of infarction, using a prognostic score derived from the Perth Coronary Register (the PCR score), the estimated decline was still 12.2% in each year. During the nine years, the rate of coronary surgery in the post-infarction year rose from 1.5% to 12.0%. Overall, the surgically treated cases had a lower case fatality rate (1.6%) than the medically treated cases (7.7%). However, the surgical cases had a better prognosis at the time of infarction than the medical cases. When the severity of infarction (PCR score) and year of admission were considered, coronary surgery in the post-infarction year had no independent effect on outcome.