The term minimally invasive coronary artery bypass grafting (CABG) is not well defined. According to one definition, avoidance of cardiopulmonary bypass (CPB) is considered essential in decreasing the morbidity associated with conventional CABG.1 Other authors consider median sternotomy as a potential source for morbidity, due to increased risk of deep sternal wound infection and mediastinitis and delayed return to daily activities.2 Accordingly, a number of surgical strategies have evolved to avoid the need for extracorporeal circulation and minimize surgical access. Furthermore, eluding aortic manipulation and complete arterial revascularization are operative strategies that focus on improving short and long-term results. Likewise, it was widely recognized that conventional harvesting techniques for bypass grafts are often associated with wound-healing problems, especially in diabetic patients. As a consequence, endoscopic harvesting techniques for both, venous and radial artery grafts have been developed.
OFF-PUMP CORONARY ARTERY BYPASS (OPCAB) GRAFTING
Conventional CABG has been performed with CPB under cardioplegic arrest for decades. An empty, arrested heart, a bloodless surgical field, and an excellent exposure of all epicardial vessels have been considered to be the key factors for the success of this procedure. Excellent results and constantly declining mortality despite the ever-increasing risk profile of patients (Davierwala) have made standard CABG the “bread and butter” of our profession.3 Anecdotal reports on the deleterious effects of CPB and systematic reports that examined the pathophysiology of extracorporeal circulation began questioning the dogma, “the pump is your friend.” CPB is associated with (1) a systemic inflammatory response, (2) release of cytokines, (3) activation of the clotting cascade, (4) metabolic disturbances, and (5) microembolization among numerous other adverse effects. Although well tolerated by most patients, these effects alone or in combination may cause substantial morbidity, thus negatively affecting the results of the procedure. With an ever-aging population and increasing comorbidity, surgeons all over the world sought to further minimize the risk of CABG, and it seemed logical to question the role of CPB in CABG.
The evolution of off-pump coronary artery bypass (OPCAB) grafting is closely linked to the development of stabilizers that became available in the early 1990s. Initially, only pressure stabilizers were developed, but it soon became obvious that exposure of vessels on the posterolateral and inferior walls of the heart would require additional means of support. Hence, OPCAB gained greater popularity when vacuum-assisted stabilizers were introduced by the Utrecht group, which facilitated localized myocardial immobilization for all territories. Additionally, it was also recognized that OPCAB requires a team approach between the surgeon and anesthesiologist so as to prevent sudden hemodynamic changes during the procedure and to manage the same when they do occur.
OPCAB is performed under general anesthesia in most centers. Incidental reports in literature demonstrate that OPCAB can also be performed under high epidural anesthesia in an awake patient breathing spontaneously.4 Standard monitoring is used. In ...