Over the past several years, there has been a great increase in interest in performing coronary artery bypass graft (CABG) surgery without cardiopulmonary bypass (CPB). Initially in the United States efforts were primarily directed at “minimally invasive” direct coronary artery bypass (MIDCAB), a procedure in which an in situ left internal mammary artery (LIMA) graft is anastomosed to the left anterior descending (LAD) artery through a small left anterior thoracotomy. This procedure was developed to compete with angioplasty for LAD lesions, its proponents emphasizing the decreased cost and time of recovery compared to conventional CABG, usually performing it on younger, healthier patients. However, as time passed, the more widely adopted approach has been to perform CABG surgery on one or more vessels through a full median sternotomy but without CPB, a procedure called off-pump CABG (OPCAB). Its purpose is to provide adequate coronary revascularization while avoiding the morbidity associated with CPB, such as coagulopathy, pulmonary dysfunction, renal insufficiency, and CNS injury. This chapter will discuss how echocardiography can facilitate the management of patients undergoing these procedures.

A few surgeons have performed CABG without CPB for many years (1,2,3). But its widespread application of OPCAB occurred with the development of techniques that enable the performance of distal coronary anastomoses on a beating heart. Early on, drugs such as beta antagonists were used to decrease the heart rate and contractility to help provide a quiet surgical field. But more recently, retracting and stabilizing devices have been developed that usually provide an immobile surgical field without the need for pharmacological intervention (Fig. 26.1).

There are several theoretical advantages of performing CABG surgery without CPB compared to conventional CABG. Proponents of OPCAB claim that it costs less than CABG with CPB. While one might think the cost for disposable equipment might be less, in fact, most of the disposable epicardial stabilization devices actually cost more than the disposables needed to put a patient on cardiopulmonary bypass. Costs for personnel are the same because OPCAB is done with a bypass pump and perfusionist standing by. OPCAB would cost less if patients recover more quickly, are extubated sooner, spend less time in the ICU, and are discharged sooner from the hospital than conventional CABG patients. Reports in the literature suggest that this is the case (4,5). The main theoretical advantage of OPCAB, however, is its lack of the untoward effects of CPB, especially in patients with existing impairment of pulmonary, renal, or central nervous system function. OPCAB may be especially beneficial for patients with atherosclerosis of the ascending aorta. Atheroembolism from cannulation and clamping of the ascending aorta for CPB is an important cause of perioperative stroke in these patients (6). With the use of in situ internal mammary artery grafts, OPCAB allows revascularization of the coronaries without touching the aorta. Using a partially occluding aortic clamp (“j” clamp) to construct proximal anastomoses for grafts would largely negate this advantage of OPCAB. There are at least two theoretical disadvantages of OPCAB compared to CABG with CPB. First, the positioning and stabilization of the heart and the occlusion of the coronary arteries required to construct grafts with this technique may cause hemodynamic instability, especially in patients with poor ventricular function. Second, the quality of distal coronary artery anastomoses performed on a beating heart may not be as good as those made with the quiet, clear field provided by CPB, possibly causing a lower rate of graft patency. Reports suggest comparable patency rates for the two techniques in the short term, but it will be some time before long-term patency rates can be compared.