Clinical data for DURABILITY II study presented at ISET 2012


Jon Matsumura, Division of Vascular Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA, presented one-year results for DURABILITY II, a clinical study set to evaluate the safety and efficacy of the EverFlex stent (Covidien) for peripheral artery disease, at the International Symposium on Endovascular Therapy (ISET) in Miami, Florida.

DURABILITY II enrolled 287 patients at 44 investigational sites in both the USA and Europe. The study evaluated the safety and efficacy of a single self-expanding stent up to 20cm in length. The study focused on patients with atherosclerotic disease of the superficial femoral artery and superficial femoral and proximal popliteal arteries.

Patients with lesions up to 18 cm in length were evaluated. The study’s primary endpoints were 30-day major adverse event rate and primary patency at one year, compared to performance goals published by VIVA Physicians (VPI). The mean age of subjects was 68 years, with 66% male. Prominent comorbidities included hypertension (88%), hyperlipidemia (86%), and diabetes (43%). The mean lesion length as measured by core laboratory was 89.1mm, while the mean normal-to-normal lesion length measured by sites was 109.6 mm.

No major adverse events occurred at 30 days. Primary patency at one year was 67.7% when analysed by simple proportions of patients patent; using Kaplan-Meier time-to-event analysis, it was 77.2%. The results met predetermined VPI performance goals for safety and effectiveness. The one-year stent fracture rate was 0.4%.

“In another new chapter of minimally invasive treatment of peripheral artery disease, DURABILITY II evaluated a novel longer stent system that offers the option of single stent treatment of extensive symptomatic femoral artery disease,” said Matsumura. “The results are impressive.”

The results from this Investigational Device Exemption study are included in the pre-market approval application of the EverFlex stent system, which is currently under review by the US Food and Drug Administration.

The EverFlex stent system is designed to enable physicians to treat long lesions in peripheral artery disease patients with a single stent, thereby minimising the occurrence of stent fractures. Previous studies have reported stent fracture in overlapped nitinol stents. The intent is to eliminate the need for overlapping two short stents by using one long stent in order to reduce the possibility of stent fracture.