CABG Equally Safe in Elderly Patients Whether On- or Off-Pump

Download this article's Factoid in PDF (& PPT for Gold Subscribers)

On the heels of a large randomized trial showing equivalent outcomes in patients receiving on-pump vs. off-pump—with the heart still beating—coronary artery bypass graft (CABG) surgery, new findings confirm similar results for the 2 procedures in the elderly, according to a Danish study published online April 20, 2012, ahead of print in Circulation.

In the recent CORONARY trial, presented March 26, 2012, at the annual American College of Cardiology/i2 Scientific Session in Chicago, IL, and published simultaneously in the New England Journal of Medicine, researchers randomized 4,752 patients to on- or off-pump CABG. The largest prospective, randomized trial to date comparing the 2 surgical techniques, CORONARY showed similar outcomes for the 2 procedures at 30 days.

For the Danish On-pump versus Off-pump Randomization Study (DOORS), researchers led by Kim Houlind, MD, PhD, of Aarhus University Hospital (Aarhus, Denmark), randomized 900 nonemergent patients 70 years of age or older to on- (n = 450) or off-pump (n = 450) CABG at 4 hospitals in Denmark. To participate in the trial surgeons (n = 12) were required to have performed at least 25 off-pump procedures with anastomoses to the obtuse marginal branches of the circumflex artery, indicating an intermediate level of experience compared with the more experienced surgeons in the CORONARY trial.

Hard Outcomes, QOL Measures Similar

Patients in the off-pump group received a higher number of mean grafts than the on-pump group (2.9 vs. 3.1; P = 0.007). They also experienced increased blood loss during surgery and within the first 24 postoperative hours (1,500 mL vs. 1,243 mL; P < 0.001). In addition, the cross-over rate from off- to on-pump CABG was 13%.

On intent-to-treat analysis, hard outcomes were equivalent between the 2 groups at 30 days, including the primary endpoint of death, stroke, and MI (table 1).

Table 1. Outcomes at 30 Days

In a noninferiority analysis, the researchers were unable to prove noninferiority (P = 0.49) of off-pump CABG to the on-pump procedure with regard to the primary endpoint. Thirty-day outcomes remained equivalent between the 2 groups in the 90 randomized patients who were 80 years or older. At 6 months, mortality was still similar between the overall groups (4.2% with off-pump CABG vs. 4.7% with on-pump CABG; P = 0.75).

Study subjects also answered questions at baseline and 6 months on the Medical Outcomes Study Short Form-36, showing significant improvement in scores assessing quality-of-life measures such as physical functioning and mental health, with no difference in improvements between the off-pump and on-pump groups.

The study authors conclude that “[b]oth techniques are relatively safe and can be performed with a fairly low rate of major complications in patients with high age and co-morbidities.” They note that contrary to previous published opinions calling for off-pump CABG only in selected patients and under the care of skilled surgeons, “the results of the present study do not prove [off-pump CABG] to be inferior to [on-pump CABG] when applied to a general, elderly population,” and in fact attest to the “comparative safety of the operations.”

A ‘Respectable’ Procedure

Robert A. Guyton, MD, of the Emory University School of Medicine (Atlanta, GA), noted that the DOORS and CORONARY trials have helped reverse the prevailing opinion regarding off-pump CABG after the ROOBY trial, published in 2009, showed worse results with off-pump compared with on-pump CABG.

“ROOBY said off-pump CABG was something that should be on its way out,” Dr. Guyton told TCTMD in a telephone interview. “CORONARY and this study have reversed that opinion and moved it back into the realm of respectability. These 2 studies are really a very effective counterbalance to ROOBY.”

He added that the failure to find noninferiority should not detract from the results of the current trial, noting that the study design was probably overly optimistic in expecting a 50% reduction in complications with off-pump CABG. “It was underpowered for a smaller reduction,” Dr. Guyton said. “That doesn’t take away from the results because the findings that the 2 procedures seem equivalent with surgeons of intermediate experience is probably accurate.”

Off-Pump for Those at Higher Risk?

The planned reduction was due to the expectation that off-pump CABG would be safer in older patients. “The more at risk you are, the more you will benefit from off pump,” explained André Lamy, MD, of McMaster University (Hamilton, Canada), and principal investigator of the CORONARY trial. “On-pump is better in low-risk patients.”

In particular, elderly patients seem to tolerate cardiopulmonary bypass less well, Dr. Guyton added.

From a patient perspective, the trial results mean that “if you go to an institution that has good results with coronary revascularization, the best thing to do is let that institution do what they do best and not ask or demand that they do something other than what they have done to achieve their good results,” Dr. Guyton said. “It varies by institution. Duke, for example, is very much an on-pump site, while Emory is very much an off-pump site.”

“Both techniques are good and safe,” Dr. Lamy commented. “The benefit of off-pump [is better for] people with intermediate and moderate-to-high risk, and people at low risk are probably better off with on-pump, and I’ve changed my practice accordingly.”

He added that off-pump CABG is more difficult to perform and many surgeons are reluctant to learn the procedure. Nevertheless, “people should learn to do off-pump, and if they’re in the middle of the learning curve, they just have to convert more [to on-pump] and that’s okay if you do it early,” Dr. Lamy said. “A wise surgeon will do both techniques and will change their technique for the benefit of the patient.”

 

---

Source:
Houlind K, Kjeldsen BJ, Madsen SN, et al. On-pump versus off-pump coronary artery bypass surgery in elderly patients: Results from the Danish On-pump versus Off-pump Randomization Study (DOORS). Circulation. 2012;Epub ahead of print.

 

 

Related Stories:

• CORONARY Bypass Shows Similar Results Whether On-Pump or Off
• Meta-Analysis: Off-Pump Approach Increases Mortality Risk in CABG
• Off-Pump CABG Reduces Postoperative Stroke vs. Standard Surgery

 

Click here for a listing of companies that provide support to the Cardiovascular Research Foundation, owner and operator of TCTMD.