Fewer Neurological Events Seen in Off-Pump CABG Procedure

Significantly fewer neurological adverse events occur when surgeons perform coronary artery bypass graft surgery if patients are not placed on the cardiopulmonary bypass pumps, according to a large case review.

“Off-pump surgery improves neurological outcome compared to on-pump surgery,” said Nirav Patel, MD, a surgeon with the Cardiothoracic Centre, Liverpool, United Kingdom, speaking yesterday at the 38th annual meeting of the Society of Thoracic Surgeons.

The results confirm the hypothesis that off-pump operations would reduce neurological problems associated with bypass surgery, he said. Dr. Patel and his colleagues reviewed the neurological outcomes of 2,327 consecutive patients undergoing cardiac bypass graft surgery (CABG) either on-pump or off-pump at his institution and at a second clinic in Manchester, United Kingdom. They also examined the outcomes of the off-pump procedure based on whether the patients underwent aortic manipulation.

Patients in the study were evenly matched, with an average age of about 62 years. There were a few more women in the group that received aortic manipulation with off-pump surgery — 27 percent versus 20 percent in the other arms of the analysis. The average body mass index (BMI) was about 27 for each group.

Results show that 1,210 patients were placed on a cardiopulmonary pump, and 19 (1.6 percent) of those patients experienced focal neurological deficits. That compared to two patients (0.4 percent) of the 520 patients who were off-pump during the procedure and who also underwent aortic manipulation. A total of 597 patients underwent the operation off-pump without receiving aortic manipulation. Three (0.5 percent) of these patients had focal neurological deficits, Dr. Patel noted. The difference between the on-pump and off-pump neurological outcomes was significant to the p=0.03 level.

The analysis also took into consideration other risk factors including diabetes status, the possibility that the patient was having a second CABG procedure, presence of renal function, peripheral vascular disease and other possible confounders.

There appeared to be a trend toward a mortality benefit with off-pump surgery. Thirty patients (2.5 percent) in the on-pump group died in-hospital, compared to five patients (1 percent) who were treated off-pump with manipulation and nine patients (1.5 percent) who died who received off-pump surgery without manipulation. The difference between on-pump and off-pump achieved a value of p=0.08, not reaching statistical significance.

“The skeptics of off-pump surgery will point out that the researchers didn’t do all the maneuvers that are now state-of-the-art to protect patients undergoing on-pump surgery,” said Lishan Aklog, MD, director of minimally-invasive cardiac surgery at Mount Sinai School of Medicine, in New York.

Dr. Aklog suggested that advances in clamping procedures and use of ultrasound to scan vessels for possible emboli have been employed to reduce the risk of neurological consequences during on-pump surgery. He said he is an advocate of off-pump surgery, adding, “The magnitude of the difference was great enough to stand up and make the study implications valid.”

Dr. Aklog said that it might take a prospective randomized trial to settle the question.