GREAT Study on Renal Artery Stenosis Debated

By Jane Salodof MacNeil

NICE, FRANCE -- Second-year results from a trial comparing sirolimus-eluting and bare stents in patients with renal artery stenosis found a trend toward better clinical results only with the 0.018-inch Palmaz Genesis stent.

Target lesion revascularization occurred at a lower rate with the sirolimus-eluting stent: 3.77% vs. 11.5% of the 105-patient study. The difference did not reach statistical significance, however, reported investigator Claudio Rabbia, M.D., at the annual meeting of the Cardiovascular and Interventional Radiological Society of Europe.

"The latest technology for renal artery stenting is safe and effective," said Dr. Rabbia, director of diagnostic radiology at San Giovanni Battista Hospital in Turin, Italy. "The addition of drug-eluting properties appears beneficial. The study needs confirmation in additional larger and randomized trials."

Eleven European centers participated in the Palmaz Genesis Peripheral Stainless Steel Balloon-Expandable Stent, Comparing a Sirolimus-Coated Versus an Uncoated Stent in Renal Artery Treatment trial, known as the GREAT study.

The investigators did not randomize patients but assigned them sequentially: 52 were treated with the bare stent and 53 with the drug-eluting stent.

All patients had 50% or greater renal artery stenosis. The study excluded those with renal artery occlusion, multiple lesions in a single artery, or a need for multiple stents. The patients receiving the drug-eluting stents were older on average: 67.7 years vs. 63.7 years for the bare-stent group. They also had greater involvement of the renal artery, whereas ostial involvement was greater in the bare-stent patients, according to Dr. Rabbia.

Technical success reached 100% with the bare stent and 98% with the drug-eluting stent, he said. Conversely, procedural success reached 98% with the bare stent and 100% with the drug-eluting stent.

The main end point, mean angiographic in-stent diameter stenosis at 6 months, was comparable for the two groups: 23.9% with the bare stent and 18.7% with the drug-eluting stent. Creatinine levels and hypertension results were similar.

"We detected no significant difference in clinical benefit in treatment of hypertension or renal insufficiency," Dr. Rabbia said.

At 2 years, no statistically significant differences were reported in the binary restenosis rate or late lumen loss. Four patients in the bare-stent group and nine in the drug-eluting stent group had worsening of renal function. Though three patients in the drug-eluting stent group died, compared with none of the patients given a bare stent, this was not statistically significant.

Speaking from the audience, Roger M. Greenhalgh, M.D., challenged the design of the GREAT study. "You treated one type of lesion with bare stents and a different type of lesion with sirolimus-eluting stents," said Dr. Greenhalgh, head of the department of vascular surgery at the Imperial College School of Medicine and Charing Cross Hospital in London. "We all want to know if drug elution is of benefit, but the way to know is to treat the same lesion in two ways. Then we might know.

"What I take from your study is a great experience, but we still don't know the answer," he said.

"I totally agree with you," Dr. Rabbia responded.

When asked to comment on this story, Brian Rubin, M.D., director of the noninvasive vascular laboratory, Barnes Jewish Hospital, St. Louis, stated that the remarks by Dr. Rabbia on the addition of drug-eluting properties appearing beneficial are not supported by the data.

"While the bare metal stent and DES groups treated dissimilar lesions, it appears as though drug-eluting stents do not represent a significant advance in the treatment of renal artery stenosis," he added.