Stent May Improve Stenosis Outcomes

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In a small series of patients with renal artery stenosis, primary patency at six months was 92%.

 

WASHINGTON D.C.—A novel stent may have advantages over previous stents in the treatment of renal artery stenosis (RAS).

 

This newer generation device, the Palmaz Blue cobalt chromium balloon expandable stent, has an excellent technical success rate and excellent primary patency for renal stent artery applications, according to new study findings presented here at the Society of Interventional Radiology's 33rd Annual Scientific Meeting.

 

Renal artery stent procedures have been criticized by many in the nephrology community because of their questionable clinical benefit in renal function and the high rates of in-stent stenosis. Most renal artery stent procedures studied so far, however, have employed stainless steel balloon expandable stents. Researchers at Mount Sinai Medical Center in New York studied whether better results are possible with the Palmaz Blue stent.

 

Over a 12-month period, the researchers recorded in an endovascular database all cases of renal artery stenting at a single institution using the Palmaz Blue stent. In this study, all the cases were scheduled for clinical follow-up and duplex ultrasonography or CT angiography at one month, at six and 12 months, and then annually.

 

All cases were retrospectively reviewed for the clinical and technical details of the procedure, including incidence of complications. The team reviewed each case for primary patency assessed by duplex or CT angiography as well as changes in creatinine clearance at follow-up.

 

100% technical success

A total of 55 stents were placed in 41 patients with RAS. The group consisted of 14 men and 16 women. Patients had a mean age of 75 years (range, 53-92). Forty-seven lesions were de novo and eight were in-stent stenosis from previous stainless steel stents.

 

The technical success for delivery and deployment of the Palmaz Blue stent was 100%, according to the investigators. All of the cases were performed with unfractionated heparin and dual anti-platelet therapy. Access site hematomas requiring transfusion developed in five patients (17%).

 

The mean follow-up for this retrospective study was 6.3 months (range, 1-12 months). At six months, primary patency was 92% and creatinine clearance had improved by mean 7 mL/min.

 

“The reason this material was introduced for this application was to decrease the size of the delivery system,” said investigator Robert Lookstein, MD, assistant professor of radiology at Mount Sinai. The stent is smaller and that makes the procedure safer for the patients and allows the operator to deliver the stents to a larger group of patients.

 

“The smaller the system, the more flexible and the more deliverable [it is],” Dr. Lookstein said. “The big picture is that the newer stent systems are going to improve the technical success rates from previous historical data thanks to newer design and greater durability.”

 

The Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) study is under way to examine whether percutaneous stent placement is comparable or superior to optimal medical management. The trial, which is funded by the National Institutes of Health in Bethesda, Md., is enrolling patients with renal artery stenoses of greater than or equal to 60% and less than 100%.

 

Results from that study are not expected until 2010.  However, Dr. Lookstein said he believes studies over the next couple of years will show that percutaneous stenting of renal arteries will prove to be of clinical benefit in selected patients.

 

“Currently, percutaneous renal stent placement is a very controversial area,” he told Renal & Urology News.

 

“There are many people who feel strongly about this. Some internists, nephrologists, and cardiologists feel clinical efficacy has not been proven against optimal medical management. On the other hand, there are other clinicians, including many interventional radiologists, who feel that the procedure does offer significant clinical benefits.”

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