Determinants of left ventricular function following aorto-coronary bypass surgery.

Ventricular function was evaluated by the development of ventricular function curves from the vulumes stress of angiographic contrast media in 30 patients before and an average of 5 months after coronary bypass surgery. Patients were grouped according to preoperative operative indications, perioperative events, and postoperative status to determine the most important factors affecting postoperative ventricular function. Progression of lesions in the native coronary circulation correlated most significantly with a decrease in postoperative ventricular function. In 18 of 19 patients the changes in native coronary circulation were progression to complete occlusion. Seventy-three per cent of these changes were associated with a patent graft distal to the change. Patients with very ischemic ventricles as evidenced by a markedly positive stress test (greater than 2 mm. ST depression) and/or main left coronary obstruction maintained or improved postoperatively ventricular function. Increase in postoperative ejection fraction was often associated with decrease in aortic mean pressure, making it difficult to use this parameter to evaluate postoperative ventricular function.