RSNA News - November 2004

Landmark Study Compares Renal Artery Interventions to Medications

Radiologists should be encouraged that obtaining NIH funding for randomized clinical trials of disease management is feasible.
— Timothy P. Murphy, M.D.

Timothy P. Murphy, M.D.

CORAL Co-Principal Investigator

Enrollment is about to begin for the Cardiovascular Outcomes in Renal Atherosclerosis Lesions (CORAL) trial, an unprecedented national effort that will involve radiology, cardiology and nephrology.

The $28 million trial, funded largely by the National Heart, Lung and Blood Institute, will study 1,080 patients with renal artery stenosis. These patients will be randomized over about 100 sites. Each will be followed for three-and-a-half years.

"Half the cohort will get medications and the rest will get non-drug eluting stents plus medications," says one of the eight co-principal investigators, Timothy P. Murphy, M.D., an interventional radiologist at Rhode Island Hospital and Brown University Medical School in Providence. "We're going to see who has a lower incidence of heart attacks, heart failure, strokes and kidney failure. With that study design, we should be able to tell definitively whether there's any benefit to adding the stent procedure."

Dr. Murphy says three randomized trials of renal artery angioplasty (RAA) surprisingly found no increased benefit when compared with medications. "At the same time, there has been a 2.4-fold increase in the number of procedures done," he explains. "So, if a procedure isn't shown to do any good, why are we dramatically increasing the number of procedures we perform? That's the impetus for the CORAL study. Instead of looking at a single surrogate endpoint—blood pressure—we'll examine hard, clinical endpoints."

Separate studies already under way are gathering similar data for carotid artery stenting. A peripheral artery stenting trial is in the planning stages.

Louis Martin, M.D., a professor in the Department of Radiology at Emory University, will lead the study at his site. "CORAL is an extremely important study," he says. "RAA and stenting have supplanted surgery. Ninety-five percent of renal arteries that are primarily treated for stenosis are treated by these interventions. There are millions of people in this patient population. Hopefully, CORAL will give us an idea of who we should treat and when."

Radiology's Leading Role

Dr. Murphy is also excited about the role radiology is playing in CORAL. "This is one of the few multicenter, randomized clinical trials of disease therapy that has had radiology represented from the beginning. In CORAL, radiology is working with cardiology and nephrology as peers to answer this question," he says. "Many radiologists were integral to getting this study off the ground, from planning and designing to funding and implementation. Radiologists should be encouraged that obtaining NIH funding for randomized clinical trials of disease management is feasible. We should be encouraged to scientifically evaluate our technologies and therapies through NIH funding mechanisms."

In the September 2004 issue of the American Journal of Roentgenology, Dr. Murphy is the lead author of a study showing a dramatic increase in the number of renal revascularizations performed between 1996 and 2000 among Medicare beneficiaries. The total volume increased 62 percent to nearly 22,000 procedures. At the same time, cardiologists increased their annual volume by nearly four-fold.

(left) Renal artery stenoses before treatment and (right) after stenting procedure. Images courtesy of Timothy P. Murphy, M.D.