Assisted Circulation by Veno-Arterial By-Pass

Anoxic arrest during open-heart surgery, though now obsolete, presented an opportunity to evaluate veno-arterial bypass in treating acute myocardial failure. After periods of complete normothermic aortic occlusion 12 patients required extracorporeal support up to 70 minutes. Premature interruption of circulatory assistance allowed myocardial deterioration, hypotension, and even ventricular fibrillation. Support of coronary circulation was critical despite the increased pressure work produced by the pump. In one case arterial return was synchronized to occur during diastole and thus reduce systolic pressure work. Veno-arterial bypass was used for emergency resuscitation and maintenance in one patient with massive pulmonary emboli and in another with aortic stenosis pending surgical correction.