Bypass Surgery Safe On or Off Pump

Coronary artery bypass surgery safe to perform either method

(RxWiki News) Previous studies have shown mixed results when it comes to debating whether coronary artery bypass surgery is safer "on pump" with the heart stopped or on a beating heart.

The large CORONARY trial has found that both methods are just as safe, though there are clinical differences between the two when it comes to the procedure and recovery.

"Talk to your cardiologist about the benefits of each bypass method."

While patients were being recruited for the CORONARY trial, initial published results from the ROOBY (Randomized On/Off Bypass) trial suggested worse outcomes for off-pump bypass.

Dr. André Lamy, from the division of cardiac surgery at Canada’s McMaster University and one of the study’s lead investigators, said that after those preliminary ROOBY results, investigators reviewed the CORONARY trial design and decided to continue the trial with approval from the Data Safety Monitoring Board.

ROOBY was through the U.S. Veterans Administration at only 18 hospitals, while the CORONARY trial was considerably larger, and included more women, sicker patients and surgeons who were more experienced with the off-pump procedure, he said.

In the off-pump procedure a surgeon uses a retractor to lift the still-beating heart to perform the bypass graft. In the on-pump method, a patient's heart is stopped and blood is circulated through a heart-lung machine, where it is oxygenated before being returned to the patient.

During the randomized CORONARY trial at 79 medical centers in 19 countries, which began in October 2007, 4,752 patients with coronary artery disease were enrolled. The participants already planned to undergo coronary artery bypass graft surgery. They were randomly assigned to the on-pump or off-pump method after an assessment to ensure they were a suitable candidate for the chosen technique.

The mean patients age was 68 years old, and 81 percent of participants were men. The average number of grafts performed per patient was three.

Both procedures were found to be safe. Among off-pump patients, 9.9 percent died, had a heart attack, stroke or kidney failure at 30 days after the procedure as compared to 10.3 percent in the pump group. The difference was not considered statistically significant. There also were no differences found among the composite outcome, which combines outcomes into one measure.

They did find some differences between the types of procedures though. When the procedure was performed on a beating heart, fewer blood products were needed and patients were less likely to need an additional operation for bleeding, pulmonary complications or acute kidney injury. However, Dr. Lamy noted that there was a higher rate of revascularization in off-pump patients, meaning that the surgery did not completely work, though that complication was rare.

“This introduces a new concept in cardiac surgery, allowing patient-specific decisions for bypass surgery,” Dr. Lamy said. “Off-pump procedures are trickier and more stressful, and the benefit is for the patient, not the surgeon, so in many places, they’re simply not done. My goal is to persuade surgeons to individualize the technique – to do off-pump bypass or on-pump when indicated – so their patients will benefit.”

The study was presented Monday at the American College of Cardiology’s annual scientific sessions.

Review Date: 
March 26, 2012