SilverHawk Midterm Durability in Question

By Sharon Worcester 

RIO GRANDE, P.R. -- The SilverHawk plaque excision device proved safe and effective for reducing early symptoms in patients undergoing lower extremity atherectomy in a recent study, but durability was poor, with significant patency and limb loss at 1-year follow-up, Dr. Timur P. Sarac reported at the annual meeting of the Southern Association for Vascular Surgery.

The retrospective review of outcomes in 73 patients who had 167 lower extremity vessels atherectomized with the device between January 2004 and January 2006 showed that cumulative 1-year primary, primary assisted, and secondary patency rates were 43%, 49%, and 57%, respectively. Limb salvage was only 75%, and survival was 90% at 1 year, said Dr. Sarac of the Cleveland Clinic Lerner School of Medicine, Cleveland, Ohio.

Based on these findings the initial excitement over this device, which was approved by the U.S. Food and Drug Administration in 2004 and is marketed by FoxHollow Technologies, Inc. of Redwood City, Calif., has been tempered, Dr. Sarac said.

"We're much more reluctant to use this on a routine basis, given these findings and those from other reports," he said.

Patency rates in the current study did not differ based on vessel location, degree of stenosis, or number of vessels treated, although there was a trend toward improved patency with stenotic vs. occluded vessels.

Patients included 42 men and 31 women with a mean age of 68 years. The most severe symptom was claudication in 17% of patients, rest pain in 27% of patients, and tissue loss in 56% of patients; however, most patients had multiple symptoms: 85% of patients reported claudication, and 74% reported both rest pain and tissue loss.

A total of 78 legs were treated (5 patients had both legs treated) and up to 5 vessels per leg were treated, with a mean of 2.3 vessels treated per patient.

A total of 63 vessels in 33 patients received adjunctive treatment with either percutaneous angioplasty (61 patients) or percutaneous angioplasty plus stent (2 patients). A total of 84 vessels were totally occluded, and 83 were stenotic.

At 30 days, there were no operative deaths and no acute limb loss. Mean ankle brachial index increased from 0.57 preoperatively to 0.82 at 30 days. Symptom improvement averaged about 80% for claudication, rest pain, and tissue loss.

Procedural complications included one peroneal artery rupture, one femoral artery pseudoaneurysm, one access site hematoma, and one perforation. The most common complication was distal embolization in four patients. All complications were treated successfully.

Multivariate analysis showed that tobacco use, renal disease, diabetes, and tissue loss were predictors of patency loss, and diabetes and tissue loss were predictors of limb loss.

In the univariate analysis, diabetes was a significant risk factor for inferior outcomes in primary, primary assisted, and secondary patency, as well as limb salvage (hazard ratios: 2.62, 3.50, 7.19, 7.46, respectively).

The findings suggest that atherectomy of lower extremity vessels with the SilverHawk device as first-line treatment should be reserved for those patients who have compelling reasons for avoiding other open or interventional procedures, Dr. Sarac concluded.