Global left ventricular impairment and myocardial revascularization: determinants of survival

Of 2,782 patients undergoing isolated coronary artery bypass grafting (CABG) from 1970 through 1979, 196 exhibited severe global impairment of left ventricular (LV) wall motion preoperatively (LV score, greater than or equal to 15; ejection fraction, less than 0.40 in all patients and less than 0.30 in 67%). The initial 89 patients (Group 1) underwent CABG without potassium chloride cardioplegia. The subsequent 107 patients (Group 2) were given potassium chloride cardioplegia intraoperatively. Group B patients received more grafts per patient (3.1 versus 2.5; p less than 0.001) and were completely revascularized more often (72.9% versus 58.4%; p less than 0.05). Operative mortality was lower in Group B (3.7% versus 12.4%; p less than 0.025), and 5-year cumulative survival was better in Group B (88.8% versus 63.9%; p less than 0.0001). Preoperative congestive heart failure resulted in higher operative mortality (14.3% versus 4.5%; p less than 0.05) and lower 5-year survival (65.0% versus 81.8%; p less than 0.02). Complete revascularization led to higher 5-year survival (82.2% versus 66.0%; p less than 0.02) but did not alter operative mortality significantly (6.9% versus 9.1%). Potassium chloride cardioplegia may influence operative survival favorably by reducing perioperative myocardial infarction in patients with severe LV dysfunction. Long-term survival relates to completeness of revascularization and severity of congestive heart failure as variables independent of methods of myocardial protection.