Background: Coronary artery bypass grafting with cardioplegia in patients with a low ejection fraction carries a risk of myocardial ischemia. Beating heart surgery is associated with hemodynamic changes when the heart is manipulated. We assessed an alternative: minimal extracorporeal circulation for coronary artery bypass grafting on a beating heart in patients with a poor ejection fraction.
Methods: From January 2000 to January 2002, 50 patients with an ejection fraction of less than 35%, who represented 10% of all patients undergoing coronary artery procedures, underwent revascularization on a beating heart with assistance. We used a closed cardiopulmonary bypass system with a centrifugal pump without reservoir, and the surgical strategy was modified to avoid aortic cross-clamping and to decrease bypass time.
Results: The main preoperative characteristics were: age (mean +/- SD) of 64 +/- 11.2 years (range, 41-87 years), 35 male patients (70%), mean left ejection fraction of 24.8% +/- 11.2%, and a mean EuroSCORE of 5.8 +/- 2.7. Revascularizations of 146 distal anastomoses (2.9 +/- 0.7 grafts/patient) were completed. Twelve percent were double bypass, 86% were triple bypasses, and 2% were quadruple bypasses; the mean bypass time was 64.2 +/- 26.2 minutes. The mean graft number was 2.9, and the hospital mortality was 2%. Perioperative hematocrit levels were 30.1%, and 26% of patients received transfusions. Postoperative data showed a median extubation time of 9 hours, a median intensive care unit stay of 48 hours, and a hospital stay of 8 +/- 2 days. Postoperative complications included inotropic support (14%), cerebrovascular events (2%), reoperation for homeostasis (4%), delayed sternal closure (2%), and mediastinitis (2%). Peak troponin Ic level remained a low 2.4 +/- 1.9 g/mL. Follow-up at 6 months was complete with 1 late mortality and with a mean ejection fraction of 30.5% +/- 10.8% for the survivors.
Conclusions: Coronary revascularization on a beating heart with extracorporeal assistance can be done in patients with a low ejection fraction. It avoids the myocardial injury associated with aortic cross-clamping and allows safe and complete coronary revascularization.