[Coronary artery bypass grafting on the beating heart in high-risk patients].Herz. 2007 Sep; 32(6):483-90.HERZ
Since the introduction of off-pump coronary artery bypass grafting (OPCAB) for coronary multivessel disease there was growing interest to evaluate the impact of OPCAB surgery compared to conventional coronary artery bypass grafting (CCAB) with cardiopulmonary bypass and cardioplegic arrest. However, subsequent prospective randomized studies and meta-analyses comparing OPCAB and CCAB surgery were performed on low-risk patients or mixed-risk populations. They usually failed to demonstrate a significant benefit of OPCAB surgery on early mortality or perioperative major cardiac and cerebrovascular events. In recent years, efforts were made to analyze the meaning of beating-heart concepts for patients with specific cardiac and extracardiac risks like ischemic cardiomyopathy, older age, renal failure, acute coronary syndrome, left main stenosis and others. For these subsets of patients several mono- and multicenter studies are available today. Even if most of them were nonrandomized and thus failed to reach evidence level A according to the AHA/ACC (American Heart Association/American College of Cardiology) definition, they still allow analyzing interim results for each specific perioperative risk factor. Particularly multi-risk patients and patients with severely reduced left ventricular function seem to benefit in terms of perioperative mortality and major morbidity by avoiding cardiopulmonary bypass and cardioplegic arrest. Analyzing early results and long-term follow-up of 364 patients with severely reduced ejection fraction<20%, the authors found a long-term benefit for patients when using OPCAB strategies particularly due to reduced perioperative mortality. Moreover, for most subsets of patients with significant extracardiac risk factors the incidence or perioperative stroke was reduced. In patients with preoperative renal and pulmonary dysfunction a decrease of corresponding organ failure was found for OPCAB strategy. For most risk populations transfusion requirements were significantly lower in OPCAB compared to CCAB surgery. In none of the patients an unfavorable outcome of beating-heart surgery compared to CCAB was shown. For emergency patients with an acute coronary syndrome presenting stable and unstable hemodynamics the authors found a clinical benefit by using beating-heart strategies. Particularly in patients with cardiogenic shock, cardiopulmonary bypass was often required to guarantee adequate perioperative organ perfusion. However, these patients seemed to benefit from avoiding global cardiac ischemia and maintaining native coronary blood flow. Follow-up results were comparable for these patients. In conclusion, beating-heart coronary artery bypass grafting seems to be advantageous in various risk populations and should be considered for patients with more than average risks for cardiopulmonary bypass and cardioplegic arrest.