ACC: On-pump CABG is not more beneficial in highest risk patients

SAN FRANCISCO—Off-pump surgery in high-risk patients is associated with a lower incidence of serious complications, and is a safer way of direct revascularization in these patients, according to the late-breaking PRAGUE-6 trial, presented March 11 at the American College of Cardiology (ACC) scientific session.

In the first study to look specifically at on-pump vs. off-pump bypass surgery among patients deemed to be at high operative risk, researchers examined the primary endpoint of patients’ combined outcomes of all-cause death, stroke, MI or renal failure requiring new hemodialysis within 30 days of their procedure. They found significantly better results among patients receiving the off-pump procedure, only half of whom experienced these outcomes compared with on-pump patients (9.2 vs. 20.6 percent).

Previous studies comparing the two techniques found similar results for on-pump and off-pump CABG, but these studies used mixed populations of high-, intermediate- and low-risk patients, explained the study’s lead investigator Jan Hlavicka, MD, a heart surgeon at the Charles University in Prague, Czech Republic. To focus on high-risk patients, researchers rated patients on the EuroSCORE, which predicts patients’ chances of dying during or shortly after cardiac surgery.

Using this method, the researchers randomized 206 high-risk patients, those with a EuroSCORE of six or higher who were scheduled for isolated coronary surgery, to receive on-pump or off-pump CABG. It took approximately five years to enroll for this trial. Overall, the trial’s participants represented only 10 percent of Charles University’s CABG population. Therefore, study discussant Michael Mack, MD, noted that this was “highly selective” group from the institution.

In addition to the primary endpoint, the researchers assessed participants’ postoperative need for blood transfusions and re-exploration for bleeding. They found that a significantly higher percentage of on-pump patients required a blood transfusion than off-pump patients (80.2 vs. 64.9 percent).

The study did not find a significant difference in the need for re-exploration for bleeding with 8.5 percent of on-pump patients vs. 3.2 percent of off-pump requiring a return to the operating room for excessive bleeding or tamponade.

“Patients, especially the sicker and older ones, should know that there is an option to be operated off-pump with potentially better postoperative outcomes,” Hlavicka said. “Our study shows the benefits of this technique to a large group of our patients. Their healthcare providers should offer this method to them.”

When the trial started, Hlavicka said that about 40 percent of patients were referred for on-pump CABG, but since that time, the percentage has dropped to 20, due to their findings.

“Who should I still consider performing on-pump surgery?” questioned Mack. Hlavicka responded that this would be up to the experienced specialists, but there was a general consensus on the panel that the use of on-pump will continue to drop.

Hlavicka noted that this study is limited to the first 30 postoperative days, so further observation of these patients should be done to assess the long-term outcomes of the off-pump CABG procedure. He also recommended that a larger, multicenter, randomized study be done to verify the study’s conclusions.