Off-pump coronary artery bypass surgery: physiology and anaesthetic management

Increasing interest is being shown in beating heart (off-pump) coronary artery surgery (OPCAB) because, compared with operations performed with cardiopulmonary bypass, OPCAB surgery may be associated with decreased postoperative morbidity and reduced total costs. Its appears to produce better results than conventional surgery in high-risk patient populations, elderly patients, and those with compromised cardiac function or coagulation disorders. Recent improvements in the technique have resulted in the possibility of multiple-vessel grafting in all coronary territories, with a graft patency comparable with conventional surgery. During beating-heart surgery, anaesthetists face two problems: first, the maintenance of haemodynamic stability during heart enucleation necessary for accessing each coronary artery; and second, the management of intraoperative myocardial ischaemia when coronary flow must be interrupted during grafting. The anaesthetic technique is less important than adequate management of these two major constraints. However, experimental and recent clinical data suggest that volatile anaesthetics have a marked cardioprotective effect against ischaemia, and might be specifically indicated. OPCAB surgery requires team work between anaesthetists and surgeons, who must be aware of each other's constraints. Some surgical aspects of the operation are reviewed along with physiological and anaesthetic data.