MIAMI BEACH – An investigational, peripheral artery stent graft with heparin bonding showed excellent 1-year performance as long as its size matched the treated vessel, in a multicenter, single-arm study of 119 patients.
The Viabahn heparin-bonded stent graft placed in superficial femoral arteries (SFA) and oversized at the proximal edge by no more than 20%, produced a 91% primary patency rate at 12 months after the intervention, compared with a 70% primary patency rate among patients who received the graft in vessels where proximal edge oversizing exceeded 20%, Dr. Richard Saxon said at the meeting.
Dr. Richard R. Saxon
The overall 12-month primary patency rate for the 119 patients in the study was 74%, including a 79% rate in patients who received the 5-mm diameter stent graft, which was "a marked improvement" compared with prior 5-mm devices, said Dr. Saxon, an interventional radiologist and director of research at the San Diego Cardiac and Vascular Institute.
"If we treat the correct subset of patients with this newer stent graft, patency will be excellent and reinterventions low. We need to measure [vessel diameters] and do it correctly, and we’ll get excellent results. Oversizing will lead to occlusions," Dr. Saxon said. Oversizing compared with not oversizing led to "dramatically" different results.
The investigational stent graft used in the Gore Viabahn Endoprosthesis With Heparin Bioactive Surface in the Treatment of SFA Obstructive Disease (VIPER) trial appeared to perform substantially better than historical experience with the similar stent graft without a heparin-coated surface. The 12-month results in the pivotal study of the Viabahn stent graft without heparin showed a primary patency rate of 57%, suggesting that the heparin coating led to a 17% increase in primary patency, he reported.
In addition, the study achieved a 74% 1-year patency rate in patients with long, complex lesions that averaged 19 cm, and 60% of patients had stage III or IV disease based on classification by the Inter-Society Consensus Guidelines for the Management of PAD (TASC II).
The heparin-coated stent graft also featured contoured edges, designed to minimize the stenoses at proximal edges that have posed a problem with prior models. But the results showed that the contoured edge failed to eliminate edge stenosis, Dr. Saxon said.
Dr. Gary M. Ansel
"These are revolutionary outcomes," said Dr. Gary M. Ansel, an interventional cardiologist and clinical director of peripheral vascular interventions at the Midwest Cardiology Research Foundation in Columbus, Ohio. "The results show it’s not just the engineering, but also the use of the technology" that produces better outcomes. The new findings show the Viabahn heparin-coated stent graft comparable to the investigational Zilver PTX paclitaxel-eluting nitinol stent, said Dr. Ansel, who was a coinvestigator on the pivotal trials for both devices.
"Right now, these two, without a doubt, take it to a different level. They are better than everything else [for treating SFA stenoses], and are the standards against which everyone needs to compare their technology," Dr. Ansel said in an interview.
One-year patency data for the paclitaxel-coated nitinol stent, developed by Cook, were reported last year (Circ. Cardiovasc. Interv. 2011;4:495-504). Last October, a Food and Drug Administration advisory panel voted unanimously to recommend marketing approval of the paclitaxel-eluting nitinol stent, but as of late January, the FDA had not yet issued a decision.
VIPER enrolled patients with SFA lesions greater than 5 cm long at 11 U.S. sites. Their average age was 66 years, 62% were men, one-third had diabetes, 87% had hypertension, and 47% had coronary artery disease. Their average lesion length was 19 cm, and 61% of the SFA lesions had moderate or severe calcification. The study’s primary end point was primary patency in the treated SFA after 12 months, assessed by Doppler ultrasound. The results showed no impact of lesion length on outcomes, with primary patency rates in patients with lesions 20 cm or longer similar to those of patients with shorter lesions.
Within 30 days of treatment, one patient had a major adverse event, a need for bypass due to a target-lesion occlusion. The stent graft placed in this patient was "markedly oversized," Dr. Saxon said. A second patient had target lesion occlusion during follow-up to 1 year, again linked with stent graft oversizing compared with the vessel’s diameter.
Average ankle-brachial index was 0.61 at baseline and 0.9 at 12 months. At 12-month follow-up, 66 (74%) of the 89 patients assessed for their Rutherford-Becker class had class 0 disease, and 74 (83%) had experienced at least a two-class reduction in their Rutherford-Becker status. Twelve patients had a stent graft thrombosis or occlusion, with 10 of these patients having a worsening of their baseline Rutherford-Becker class. Thirteen patients required revisions for stenoses detected by ultrasound; seven of these patients were asymptomatic at the time of stenosis detection.