Coronary Artery Bypass Grafting to Acute Marginal Branch: Forgotten Coronary Artery

Background: Current practice for coronary artery bypass grafting focuses on left ventricular function, whereas there is increasing recognition right ventricular dysfunction is associated with a higher risk of mortality and morbidity. We evaluated the impact of acute marginal branch (AMB) bypass on right ventricular function. Methods: We reviewed 134 patients who underwent AMB bypass, comparing pre- and postoperative right heart catheter data. The surgical indication for AMB revascularization was multiple significant stenosis in right coronary artery across AMB or significant stenosis in AMB with lumen size of >1.5 mm. Results: The median age was 63 years, and 97 were male. The median preoperative left ventricular ejection fraction was 55%, and 22% of patients had right ventricular dysfunction by echocardiography. One hundred twenty-one (90%) cases were done by off-pump. The median number of anastomoses was 5. Saphenous vein graft was used in most cases (96%) and mainly done in sequential fashion (84%). There was a significant reduction in right atrial pressure, and diastolic and mean pulmonary artery pressure. Conversely, there was a notable increase in pulmonary artery pulsatility index and cardiac index. Preoperative mean pulmonary artery pressure and preoperative pulmonary artery pulsatility index were identified as significant independent predictors of improved post-operative pulmonary artery pulsatility index. Conclusions: Our initial investigation indicated coronary artery bypass grafting to AMB enhanced right ventricular function. This approach appeared to be advantageous for patients with preoperative pulmonary hypertension and right ventricular dysfunction. Additional research comparing coronary artery bypass grafting with and without AMB bypass is necessary to elucidate the true impact of this surgical intervention on right ventricular function and long-term survival.