Left ventricular function and coronary obstruction as predictors of survival following aorta-coronary bypass

A retrospective analysis was undertaken of clinical data and catheterization studies of 151 consecutive unselected patients who underwent aorta-coronary bypass at the University of Kansas Medical Center between 1971 and 1973. The purpose was to determine the effect of preoperative left ventricular function and extent and severity of coronary artery obstruction on operative mortality rate and long-term survival. The postoperative follow-up period ranged from 10 to 49 months and averaged 26 months. Left ventricular function was assessed by qualitative analysis of left ventricular angiograms. Severity of coronary obstruction was quantified by scoring coronary arteriograms according to the system of Friesinger and associates. Patients with normal or near normal ventriculograms were considered to have good left ventricular function. Patients showing moderate or severe impairment of contraction were considered to have poor left ventricular function. Obstruction scores ranging from 2 to 7 points were classified as low scores, and scores from 8 to 15 points were classified as high scores. Four groups of patients were identified based upon preoperative left ventricular function and obstruction severity: Group I, 29 patients with good left ventricular function and low scores; Group II, 22 patients with poor left ventricular function and low scores. Group III, 28 patients with good left ventricular function and high scores. Elective aorta-coronary bypass in these three groups was accompanied by no operative or late deaths. Group IV comprised 72 patients with poor left ventricular function and high scores. In this group there was a 10 per cent operative mortality rate (7 of 72 patients) and a 5 per cent year late mortality rate. Relief of angina occurred equally in all groups. Thus operative risk can be prospectively determined by analysis of left ventricular function and severity of coronary obstruction. Surgical treatment resulted in negligible operative and late mortality rates (0 per cent) in all patients except those in whom poor ventricular function was accompanied by severe and diffuse coronary artery obstruction. Operation should be offered to this latter group (Group IV) despite the higher operative and postoperative risk because of salutary postoperative results.