Coronary artery bypass surgery in patients with impaired left ventricular function. Predictors of hospital outcome

Abstract

This prospective study evaluates the surgical outcome of 75 consecutive patients with impaired left ventricular function, including an analysis of predictors of the short-term outcome following coronary artery bypass grafting (CABG). Seventy-five patients (mean age 64 +/- 13 years) with coronary artery disease and impaired left ventricular function (left ventricular ejection fraction [EF] < or = 40%) who underwent a coronary artery bypass surgery were prospectively studied. Echocardiography and thallium-201 myocardial scintigraphy were preoperatively performed to measure the left ventricular function and to assess myocardial viability. Postoperative echocardiography was done before discharge and six months later to evaluate recovery of left ventricular function. Five patients (6.7%) died in total: three deaths were cardiac related (4%) and two patients (2.7%) died due to other causes. The left ventricular ejection fraction improved immediately after the operation (from 32.2 +/- 6% to 39.5 +/- 8%, p = 0.01) and showed a sustained improvement at later follow-up (mean = 16.3 +/- 4.5 months) (44.0 +/- 4.0%, p = 0.01). The left ventricular wall motion score improved significantly only at later follow-up (from 12.2 +/- 1.8 to 9.4 +/- 2.0, p = 0.03). In 43 patients of whom a preoperative thallium-201 scintigraphy was available, the presence of extensive reversible defects was correlated with significant improvement in EF. On the other hand, a poor outcome was correlated with the presence of pathological Q waves in the preoperative ECG and with an increased left ventricular end-systolic volume index (> 100 ml/m2). Patients with marked left ventricular dysfunction can safely undergo CABG with a low mortality and morbidity. The presence of extensive reversible defects on preoperative thallium-201 scintigraphy is a strong predictor of postoperative recovery of myocardial function. A poor outcome of surgery can be expected in the presence of pathological Q waves on the preoperative ECG or when the left ventricular endsystolic volume index exceeds 100 ml/m2.