Myocardial revascularization began with the sentinel association between angina and myocardial ischemia. This led to the development of procedures aimed at restoring or augmenting blood flow to the heart including epicardial abrasion, pectoralis-to-myocardial muscle flaps, left internal mammary implantation, and ultimately the coronary artery bypass graft (CABG) procedure. Despite dramatic improvements in coronary stent technology and medical therapy including anticoagulants and lipid-lowering therapies, CABG is still the gold standard intervention for complex coronary anatomy including those with left main disease, multivessel disease as well as patients with left ventricular dysfunction. More recently, CABG has firmly demonstrated improved survival versus percutaneous coronary intervention (PCI) for patients with multivessel coronary disease and diabetes mellitus, sparking a renewed interest in surgical revascularization.

The contemporary challenge in surgical revascularization is to leverage the long-term patency of bypass grafts while reducing the incidence of perioperative complications, in particular, stroke. The potential causes of perioperative stroke can be conceptualized as low cerebral perfusion, especially in association with intrinsic cerebrovascular disease, and micro- and macroembolism. The major sources of emboli are microemboli from the use of cardiopulmonary bypass (CPB) and atherosclerotic emboli from manipulation of the ascending aorta. Off-pump CABG (OPCAB) has been proposed to address these limitations of surgical revascularization.

Since Vasilii Kolesov (1967) first published his series of LIMA to left anterior descending (LAD) anastomosis without the use of CPB, OPCAB has been adopted in select centers worldwide. Today, a minority of CABG procedures are performed off pump and this is due to greater technical difficulty, the lack of clear mortality benefit in large randomized controlled trials, and the suggestion of poorer patency outcomes in some series.

Mastery of OPCAB requires a focused and sustained effort to master a new set of physical and psychological skills. If precise and complete revascularization can be accomplished by OPCAB, then the morbidity attributable to aortic cannulation, clamping, cardioplegia, and the use of CPB will be avoided and the patient should benefit.

The single absolute indication for OPCAB is to facilitate surgical revascularization in a patient with a severely atherosclerotic aorta, also referred to as porcelain aorta. Here, violation of the ascending aorta for cannulation, cross clamp, or for construction of proximal anastomosis is associated with high risk of embolism and stroke. OPCAB can be used to accomplish a completely no-touch aorta technique. For this reason, every institution performing surgical revascularization should have at least one surgeon who can perform OPCAB in an emergent situation or in the case of severe aortic plaque.

In addition, there are small randomized controlled trials and a large volume of restrospective database evidence to suggest more favorable outcomes for OPCAB in patients presenting with the following risk factors:

Vulnerable, high-risk patient cohorts may benefit from avoidance of myocardial stunning, hypothermia, formation of microemboli, and systemic inflammation associated with CPB. In patients with previous stroke and the elderly, avoidance of aortic manipulation may reduce stroke risk. Patients with acute coronary syndrome may benefit from preservation of coronary flow and avoidance of myocardial stunning associated with CPB. As always, good surgical judgment based on individual patient risk factors and surgeon experience must guide decision making.

OPCAB is contraindicated in patients who are hemodynamically unstable. For instance, patients in refractory cardiogenic shock should be stabilized on CPB to unload the ventricle, lowering the workload, and decreasing the oxygen demand of an acutely ischemic failing heart.

There is no question that OPCAB is more technically difficult than on-pump CABG. This technique requires greater judgment of optimal grafting strategy, OPCAB candidacy, and coordination between anesthetist and surgeon. Some patient-related factors can make this procedure very challenging:

Persisting in a challenging OPCAB can lead to urgent or emergent conversion to CPB. In our experience, patients more likely to require conversion from an initial OPCAB
strategy to CPB include those with ischemic arrhythmias, those with severe LV dysfunction and cardiomegaly, those with deep intramyocardial coronary artery targets, and those needing coronary endarterectomy. Emergent conversion to CPB has been associated with poor outcomes in multiple published series. Depending on the experience of the surgical team, such patients may be better served with an on-pump procedure.

We do not stop aspirin preoperatively, and give 325 mg PO on the night before surgery; another 325 mg is given per rectum as the Foley catheter is inserted in the operating room.

Median sternotomy is performed and the IMAs are harvested as skeletonized grafts using a Harmonic scalpel (Harmonic Synergy, Ethicon, Somerville, NJ). Skeletonized harvest of IMA grafts minimizes sternal injury and thus potential for pain and sternal wound infection and allows for the greatest graft length. Moreover, the exposed skeletonized mammary artery facilitates sequential anastomoses. The Harmonic scalpel uses high-frequency mechanical vibration to cut and coagulate tissues (Fig. 26.1). The mammary branches can be coagulated by gently oscillating the broad edge of the scalpel against the branch. Compared with electrocautery, the Harmonic scalpel minimizes the risk of injury to the adjacent mammary and sternum during harvest. Radial artery and occasionally saphenous vein conduits are harvested endoscopically, simultaneous with skeletonized IMA harvest.