CURRENT EXPECTATIONS FOR SURVIVAL AND COMPLICATIONS IN CORONARY-ARTERY BYPASS-GRAFTING

The outcome of coronary artery bypass surgery is best assessed in term s of two independent components: the operative mortality and complicat ions on the one hand, and the late survival and relief of symptoms on the other. The expected operative mortality rate in a particular patie nt can be calculated with reasonable accuracy from preoperative risk f actors. This calculation also enables results from different units to be compared by correcting for the preoperative risk factors in the pat ient population. Despite improvements in cardiopulmonary bypass, there is still a low but appreciable incidence of subtle neuropsychological changes induced by coronary artery bypass grafting. The expected long -term results of the procedure must be determined from the results of surgery in the past. However, allowance must be made for two new influ ences. One is the expected improvement in the long-term results of cur rent surgery, due to the improved longevity of currently used graft co nduits such as the internal mammary artery. The other is the worsening of late results of present-day coronary artery bypass grafting caused by the greater number of preoperative risk factors in patients curren tly accepted for surgery, such as old age, impaired left ventricular f unction, and reoperation.