Selective left anterior descending shunting provides effective off-pump myocardial protection

Coronary artery shunting during off-pump coronary artery bypass OPCAB procedures has been addressed only infrequently. To assess the protective effect of shunting, we examined CABG patients' postoperative cardiac enzyme levels and preoperative and postoperative ejection fractions.

During OPCAB, we selectively shunted the left anterior descending coronary artery (LAD) to provide myocardial protection when ischemia developed. We prospectively gathered data from 408 consecutive patients who underwent OPCAB. Data on shunt status were available for 386 of these patients. A "flow-through" shunt providing perfusion to the distal LAD was used whenever ST-segment elevations greater than 2 mm occurred or when patients had hemodynamic compromise unexplained by cardiac manipulation. Ejection fraction was assessed 1 to 3 days preoperatively and again 3 to 10 days postoperatively. Creatine kinase (muscle/brain) levels were assessed postoperatively for 24 hours.

During OPCAB, 99 patients required shunting for presumed ischemia. Thirty-day cardiac mortality was 1.4% (4 of 296 without a shunt; 0 of 90 with a shunt). In patients without a LAD shunt, the mean peak creatine kinase index was 5.3; in patients who needed a shunt, the index was 5.2. Mean ejection fraction improved from 0.536 to 0.589 in the shunted patients and from 0.53.5 to 0.586 in the nonshunted patients.

Selective shunting of the LAD during OPCAB provides effective protection against myocardial ischemia when ischemia is detected by electrocardiogram or when hypotension develops that is unexplained by cardiac manipulation.