CORAL Study Shows No Additional Benefit for Renal Stenting Over Medical Therapy

November 18, 2013—The American Heart Association (AHA) announced that findings from the CORAL (Cardiovascular Outcomes in Renal Atherosclerotic Lesions) trial presented at the AHA’s Scientific Sessions 2013 in Dallas, Texas demonstrated that opening narrowed arteries to the kidney did not help patients any more than taking medicine alone. The National Heart, Lung, and Blood Institute of the National Institutes of Health funded the CORAL study.

The CORAL study’s lead author is Christopher J. Cooper, MD, who is Professor and Chairman of the Department of Medicine at the University of Toledo in Toledo, Ohio. Dr. Cooper and the CORAL investigators also published the study’s findings online in the New England Journal of Medicine (NEJM).

In the AHA press release, Dr. Cooper commented, “Stenting of atherosclerotic renal stenosis has been reasonable, despite several negative studies, because other studies suggested it might lower blood pressure and stabilize kidney function. But in our study, opening narrowed kidney arteries with stents provided no additional benefit when added to medications that lower blood pressure, control cholesterol levels, and block substances involved in blood clotting.”

In NEJM, the CORAL investigators stated that the background of the study is that despite two randomized trials that did not show a benefit of renal artery stenting with respect to kidney function, the usefulness of stenting for the prevention of major adverse renal and cardiovascular events is uncertain. Atherosclerotic renal artery stenosis is a common problem in the elderly, noted the investigators.

As summarized in NEJM, 947 participants who had atherosclerotic renal artery stenosis and systolic hypertension while taking two or more antihypertensive drugs or chronic kidney disease were randomly assigned to medical therapy plus renal artery stenting or medical therapy alone by the CORAL investigators. The study patients were followed for the occurrence of adverse cardiovascular and renal events (a composite endpoint of death from cardiovascular or renal causes, myocardial infarction, stroke, hospitalization for congestive heart failure, progressive renal insufficiency, or the need for renal-replacement therapy).

The CORAL investigators found that over a median follow-up period of 43 months (interquartile range, 31 to 55), the rate of the primary composite endpoint did not differ significantly between participants who underwent stenting in addition to receiving medical therapy and those who received medical therapy alone (35.1% and 35.8%; respectively; hazard ratio with stenting, 0.94; 95% confidence interval [CI], 0.76 to 1.17; P = .58). There were also no significant differences between the treatment groups in the rates of the individual components of the primary endpoint or in all-cause mortality. During follow-up, there was a consistent, modest difference in systolic blood pressure favoring the stent group (−2.3 mm Hg; 95% CI, −4.4 to −0.2; P = .03).

Renal artery stenting did not confer a significant benefit with respect to the prevention of clinical events when added to comprehensive, multifactorial medical therapy in people with atherosclerotic renal artery stenosis and hypertension or chronic kidney disease, concluded the CORAL investigators in NEJM.

In a statement from the Society for Cardiovascular Angiography and Interventions (SCAI), the society noted that the CORAL results are consistent with the current guidelines and confirm that effective medical therapy should be the first line of treatment in patients with presumed renovascular hypertension. For patients who fail medical therapy or are unable to tolerate medical therapy, stenting remains a reasonable option, SCAI stated.

SCAI advised that the CORAL findings also showed that the benefit of medical therapy alone lessened over time. At 3 to 5 years after enrollment, event-free survival declined in this patient group. The society suggested that this finding is worthy of continued study, as is the treatment of patients with hemodynamically severe lesions and those who fail medical therapy. Similar to other patient populations, in the real-world setting, optimal medical therapy may present challenges with respect to compliance and tolerance of medications. Continued study of renal stenting is needed to ensure patients have options when medical therapy alone is not enough, concluded SCAI in its statement.