Boston, MA - Results of a randomized trial show no benefit from coronary revascularization before major vascular surgery for patients with clinically significant but stable coronary disease.

The study, called the Coronary Artery Revascularization Prophylaxis (CARP) trial, is published in the December 30, 2004 issue of the New England Journal of Medicine.[1] The results were presented last fall at the American Heart Association Scientific Sessions 2004 and reported by heartwire at that time.

Dr Edward O McFalls

"In terms of how this will affect practice, I think vascular surgeons and cardiologists can have more confidence that the medications that are given at the time of the operation can protect the heart just as well as a rigorous preoperative revascularization procedure might do," Dr Edward O McFalls (Minneapolis Veterans Affairs Medical Center, University of Minnesota) said in an interview. Revascularization delays the planned vascular procedure and introduces its own complications, although mortality and morbidity related to prophylactic revascularization procedures was lower than previously reported in this study, he added.

Although current guidelines from the American College of Cardiology/American Heart Association and the American College of Physicians recommend revascularization be reserved for patients with unstable symptoms, this recommendation is based on consensus, not randomized data, McFalls pointed out. This has led to a variation in practice patterns, as some physicians elect to revascularize their patients as a precaution.

To illustrate the divergence in practice, McFalls pointed to a companion paper from this study published earlier this year.[2] Clinical tests and history from randomly selected patients participating in CARP were sent to volunteer cardiologists to offer their opinion on whether these patients should receive revascularization or medical therapy before their vascular procedure. The researchers found the likelihood for discordance between cardiologists was 54%, with a 26% chance that the opinions would be directly contradictory. The current findings, then, provide randomized data to support what is already the recommendation in the guidelines, Mc Falls said.

CARP included 510 patients undergoing surgery for expanding abdominal aneurysm (33%) or arterial occlusive disease in the legs (67%). They were randomized to receive either PCI or bypass surgery or no revascularization before their vascular surgery. (Patients requiring urgent or emergent revascularization were excluded from this study.)

Revascularization resulted in a significant delay in the vascular surgery: the median time from randomization to vascular surgery was 54 days with revascularization vs 18 days without (p<0.001). There was no difference in the delay whether PCI or CABG was the method of revascularization.

This delay was not compensated by better long-term outcome. Mortality at 2.7 years after randomization was not significantly different between groups. Although the study was not powered to look at short-term outcomes, there was no difference between the groups either in postoperative MI within 30 days of the vascular surgery or in postoperative deaths or days in the hospital.

McFalls gave kudos to the VA system for providing the funding to systematically study not a new drug or device but a strategy of patient care. The study was physician-initiated, and McFalls reports no conflicts of interest.

Dr Kim A Eagle

In an editorial accompanying the publication, Drs Mauro Moscucci and Kim A Eagle (University of Michigan Cardiovascular Center, Ann Arbor) point out that medical therapy was optimized in both groups in this study.[3] "If one carefully screens candidates for vascular surgery and excludes patients with symptoms of unstable coronary disease, left main coronary artery disease, aortic stenosis, or severe left ventricular dysfunction, and if one provides excellent perioperative medical treatment to those remaining, then coronary revascularization does not appear to provide an additional benefit in reducing the incidence of perioperative death or myocardial infarction," they write.

However, they note, "the issue of whom to screen and how to screen preoperative patients beyond a history taking, physical examination, and preoperative electrocardiography is far from settled." While many patients are protected by beta blockade, results of the DECREASE trial of bisoprolol showed a small group of patients with multiple clinical markers of risk and widespread ischemia on preoperative stress echocardiography who were not adequately protected, Moscucci and Eagle write. Cost-effective identification of this minority of patients is the subject of ACC/AHA guidelines for perioperative cardiovascular evaluation for noncardiac surgery.

"This wasn't a trial of screening, it was a trial of therapy, and clinicians still are going to be challenged to use their best clinical judgment and the technology available to us to identify and stratify the amount of left ventricular dysfunction and coronary heart disease to make the best possible recommendations for perioperative therapy," Eagle told heartwire.

What is needed now, the authors conclude, is a series of additional randomized studies to "settle remaining questions about screening and about the value of medical therapies beyond beta blockade with statins, angiotensin-converting-enzyme inhibitors, antiplatelet agents, and other myocardial protective or vascular stabilizing drugs that are in development."