Approximately 500,000 coronary artery bypass graft (CABG) surgeries are performed in the United States each year to bypass blood around obstructed blood vessels and restore blood flow to undernourished areas of the heart.

Until recently, the bypass procedure—which consists of grafting a blood vessel to the area above and below the obstructed vessel—has been done “on pump.” On pump refers to the heart-lung machine, which pumps oxygen-rich blood through the patient’s circulation, allowing the heart to be temporarily stilled during surgery. Though CABG surgery improves overall survival and quality of life, it carries an increased risk of death during and immediately following the surgery, a 15 to 20% complication rate, and two to three month recovery period. Recent studies have suggested that up to 42% of patients who undergo on-pump CABG surgery experience neurocognitive impairment—including problems with memory, concentration, and information processing—five years after surgery.

These negative consequences have spurred an increase in “off-pump” CABG surgeries, or those that are performed on a beating heart. Though off-pump surgeries have a lower risk of death over the short-term, the procedure is technically more demanding and, until now, the long-term effects of off-pump surgeries compared to on-pump CABG surgeries had not been established.

A study in the January 30, 2003 New England Journal of Medicine found no significant differences in the risk of death, stroke, heart attack, effectiveness of graft, or quality of life between on-pump and off-pump CABG procedures, one year after the surgeries. And, furthermore, off-pump surgeries were significantly less expensive and more cost effective.

About the Study

In this multicenter study, scientists from the Netherlands enrolled 281 patients, with an average age of 61, who had stable or unstable angina and needed CABG surgery on one or two obstructed blood vessels. They randomly assigned 139 patients to on-pump surgery and 142 patients to off-pump surgery.

At one year after surgery, the researchers compared the risk of stroke, heart attack, repeat CABG surgery or angioplasty, and the risk of death from any cause in the on-pump versus off-pump patients. They also compared the effectiveness of the graft as an alternate route for blood flow, quality of life, and costs per patient for the two procedures.

The Findings

At one year after surgery, 90.6% of patients who had on-pump surgery versus 88.0% of patients who had off-pump surgery were free from death, stroke, heart attack, and repeat coronary procedures. This difference was not significant.

Differences in the effectiveness of the graft and in quality of life were also insignificant. However, on average, on-pump surgery cost $1,839 more per patient than off-pump surgery, a 14.1% difference.

How Does This Affect You?

This study indicates that for select patients with one or two obstructed vessels, off-pump surgery is an equally effective and less expensive alternative to on-pump bypass surgery. If you have been advised to undergo CABG surgery, it is worth talking to your doctor about the off-pump option.

However, because the study only looked at patients with limited coronary disease, questions still remain about the relative benefits of off-pump surgery for patients with obstructions in three or more vessels. Largely because of the success of balloon angioplasty as an alternative to CABG, the majority of patients who undergo bypass surgery have three-vessel disease while fewer than 1% have single-vessel disease.