DURABILITY II “Long Stent” Study: One Year Data Presented at ISET 2012


Covidien has announced that one-year results on the use of its EverFlex™ stent for superficial femoral artery stenting were presented during the International Symposium on Endovascular Therapy (ISET) Conference.


One of the most common vascular diseases, peripheral arterial disease (P.A.D.) occurs when leg arteries become narrowed or blocked by plaque. These blockages can result in severe pain, limited physical mobility and non-healing leg ulcers. According to the American Heart Association, approximately 10 million people in the U.S. suffer from P.A.D.

The EverFlex stent system is designed to enable physicians to treat long lesions in P.A.D. patients with a single stent, thereby minimizing the occurrence of stent fractures which has been reported when shorter iterations are overlapped. The intent is to eliminate the need for overlapping two short stents by using one long stent.

Presenting the data was co-National Principal Investigator Jon Matsumura, MD, of the Division of Vascular Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin. Named DURABILITY II, the clinical study enrolled 287 subjects at 44 investigational sites in both the U.S. and Europe. The study evaluated the safety and efficacy of a single self-expanding stent up to 20 cm in length. The study focused on patients with atherosclerotic disease of the superficial femoral artery and superficial femoral and proximal popliteal arteries.

The Everflex stent system is CE marked, indicated for common and external iliac, superior femoral and sublavian artery use. It was developed by EV3, a company acquired by Covidien in 2009.

The study 

DURABILITY II enrolled patients with lesions up to 18 cm in length; its primary endpoints were 30-day major adverse event rate and primary patency at one year, compared to performance goals published by VIVA Physicians Inc. (VPI). The mean age of subjects was 68 years, with 66 percent male. Prominent comorbidities included hypertension (88 percent), hyperlipidemia (86 percent), and diabetes (43 percent). The mean lesion length as measured by core laboratory was 89.1 mm, 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 percent when analyzed by simple proportions of patients patent; using Kaplan-Meier time-to-event analysis, it was 77.2 percent. The results met predetermined VPI performance goals for safety and effectiveness. The one-year stent fracture rate was 0.4 percent.

Clinician comments 

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

FDA approval? 

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 U.S. Food and Drug Administration.

 Company comments

“DURABILITY II is part of a series of clinical trials focused on primary stenting as an important option in the treatment of P.A.D.,” said Stacy Enxing Seng, President, Vascular Therapies, Covidien. “Our significant investment in these studies demonstrates Covidien’s ongoing commitment to evidence-based medicine and clinically relevant innovation.”

Source: Covidien