Off-pump coronary artery bypass grafting in patients with left main disease: is it really safe?

In the October 2009 issue of your journal, Thomas et al. [1] report the safety of off-pump coronary artery bypass grafting (OPCABG) in patients with left main disease (LMD). However, although they address in their introduction the fact that patients with LMD are at higher risk of having calcified ascending aortas (AAs), they do not discuss this issue any further. Heavily calcified aortic root renders mobilisation of the heart hazardous, especially when attempting to expose the obtuse marginal artery (OM). We recently had a case of a 55-year-old woman presenting for 50% LMD, normal left ventricular function, a calcified AA and aortic root as well as bilateral asymptomatic 60% carotid artery stenosis. To avoid cerebrovascular accidents, it was decided to perform OPCABG. However, prior to performing any distal anastomosis, and while displacing the heart to examine the OM artery, the heart very quickly suffered from severe ischaemia, and intractable ventricular fibrillation followed, which lead us to a dramatic and prompt conversion to cardiopulmonary bypass under manual massage, using the small middle anterior aspect of the AA (the only disease free site) as an arterial cannulation site. The procedure was then done on a beating heart, avoiding aortic cross-clamping. Arteriotomies of the left anterior descending and OM arteries showed the absence of any antegrade blood flow, which confirmed the occlusion of the left main. The reason for that occlusion was most probably due to the rupture and displacement of an aortic root plaque extending into the left main. Fortunately, the patient was weaned easily from bypass, without inotropic support. No neurological deficit or other complications ensued and the recovery was uneventful. Although numerous encouraging studies showed the safety of OPCABG in patients with LMD and calcified AA [1—3], this experience indicated that this may not always be the case. Patients with LMD are more prone to having calcified AA and aortic root. We therefore think that in patients with LMD, prior to deciding on performing OPCABG, preoperative