When and how to shunt the coronary circulation in off-pump coronary artery bypass grafting.
OBJECTIVE
To assess the sequelae of temporary coronary artery occlusion in off-pump, beating heart CABG, i.e. ischemia, hemodynamic instability and the need for conversion to cardiopulmonary bypass.


METHODS
In 200 patients (150 male), mean age 60 (range 35-81) years, 365 distal anastomoses were performed, i.e. 1.8 anastomoses per patient through limited and full access. One hundred seventy six LAD, 61 diagonal, 71 RCA, 7 RPD and 50 circumflex branches were grafted. Patients were pretreated with calcium antagonists, long-acting beta-blockade and had thoracic epidural blockade. The anastomosis was constructed using two microvascular clamps, preceded by ischemic preconditioning in non-occlusive disease. Myocardial ischemia was defined as > 1 mm S-T segment elevation. A simple aorto-coronary shunt, consisting of two intravenous catheters and a 10 cm connecting tube (flow > 20 ml/min), was used in critical ischemia.


RESULTS
Ischemia occurred during 35 (10%) temporary coronary 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 introduction of the shunt (4 patients) electrocardiographic and hemodynamic parameters normalized within 30 s. The off-pump procedures could be continued uneventfully. There were no peri-operative infarctions.


CONCLUSIONS
Temporary segmental occlusion is an effective method for anastomosis suturing in off-pump, beating heart CABG. Critical ischemia was observed rarely, only in the RCA and in non-occlusive disease. Temporary aorto-coronary shunting could avoid conversion to cardiopulmonary bypass and myocardial infarction.
van Aarnhem
E E
EE
Department of Cardiopulmonary Surgery, Heart-Lung Institute, Utrecht University Hospital, The Netherlands.
Nierich
A P
AP
Jansen
E W
EW
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000714:Anastomosis, Surgical; D002315:Cardiopulmonary Bypass; D017023:Coronary Angiography; D001026:Coronary Artery Bypass / Q000379:methods*; D003326:Coronary Circulation; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D003657:Decision Making; D005260:Female; D006439:Hemodynamics; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D015428:Myocardial Reperfusion Injury / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D017682:Myocardial Stunning / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control