When and how to shunt the coronary circulation in off-pump coronary arterybypass grafting

Objective: To assess the sequelae of temporary coronary artery occlusion in off-pump, beating heart CABG, i.e. ischemia, hemodynamic instability and t he need for conversion to cardiopulmonary bypass. Methods: In 200 patients (150 male), mean age 60 (range 35-81) years, 365 distal anastomoses were pe rformed, i.e. 1.8 anastomoses per patient through limited and full access. Onehundredseventysix LAD, 61 diagonal, 71 RCA, and 50 circumflex branches w ere grafted. Patients were pretreated with calcium antagonists, long-acting beta-blockade and had thoracic epidural blockade. The anastomosis was cons tructed using two microvascular clamps, preceded by ischemic preconditionin g in non-occlusive disease. Myocardial ischemia was defined as >1 mm S-T se gment elevation. A simple aorto-coronary shunt, consisting of two intraveno us catheters and a 10 cm connecting tube (flow > 20 mi/min), was used in cr itical ischemia. Results: Ischemia occurred during 35 (10%) temporary coron ary artery occlusions. Fifteen of these (43%) were RCA. In five of these 15 patients, all with non-occlusive disease, critical ischemia occurred with bradycardia, third-degree heart block and subsequently severe hypotension, which normally requires conversion to cardio-pulmonary bypass. Following in troduction of the shunt (4 patients) electrocardiographic and hemodynamic p arameters normalized within 30 s. The off-pump procedures could be continue d uneventfully. There were no pre-operative infarctions. Conclusion: Tempor ary segmental occlusion is an effective method for anastomosis suturing in off-pump, beating heart CABG. Critical ischemia was observed rarely, only i n the RCA and in non-occlusive disease. Temporary aorto-coronary shunting c ould avoid conversion to cardiopulmonary bypass and myocardial infarction. (C) 1999 Elsevier Science B.V. All rights reserved.