One-year results of the VIASTAR trial published online in the Journal of the American College of Cardiology suggest that a heparin-bonded covered stent may be superior to bare metal stents in the treatment of long femoropopliteal artery disease.
Data from the randomised trial were published ahead of print on 10 July. In the prospective, single-blind, multicentre study 141 patients with symptomatic peripheral arterial disease were assigned to treatment with heparin-bonded, covered stents (Viabahn, Gore, 72 patients) or bare metal stents (69 patients). Clinical outcomes and patency rates were assessed at one, six and 12 months.
The authors, led by Johannes Lammer, Vienna General Hospital, Austria, wrote as background information for the study: “While endovascular treatment of short superficial femoral artery lesions revealed excellent results, efficacy in long lesions remains unsatisfactory. The hypothesis that endovascular treatment with covered stents has equal risks but higher efficacy than bare metal stents in long femoropopliteal artery disease was tested.”
In VIASTAR, mean lesion length was 19±6.3cm in the Viabahn group vs. 17.3±6.6cm in the bare metal stent group. Major complications within 30 days were observed in 1.4% of patients. In the intention to treat analysis, the 12-month primary patency rate in the Viabahn group was 70.9% (95%CI, 0.58-0.80), against 55.1% (95%CI, 0.41-0.67; log rank p=0.11) in the bare metal stent group. In the treatment per protocol analysis, the primary patency rate in patients treated with Viabahn was 78.1% (95%CI, 0.65-0.86) and for bare metal stent patients it was 53.5% (95%CI, 0.39-0.65) (HR 2.23, 95%CI, 1.14-4.34; log rank p=0.009).
In lesions ≥20cm (TASC D) the 12-month patency rate was significantly higher in Viabahn patients in the intention-to-treat analysis (Viabahn 71.3% versus bare metal stent 36.8%; p=0.01) and the treatment per protocol analysis (Viabahn 73.3% versus bare metal stents 33.3%; p=0.004).
Freedom from target lesion revascularisation was 84.6% for Viabahn (95%CI, 0.72-0.91) versus bare metal stents 77% (95%CI, 0.63-0.85; p=0.37). The ankle-brachial index in the Viabahn group significantly increased to 0.94±0.23 (versus bare metal stents 0.85±0.23; p<0.05) at 12-months.
The authors concluded that this randomised trial in symptomatic peripheral arterial disease patients who underwent endovascular treatment for long femoropopliteal lesions demonstrated significant clinical and patency benefits for heparin-bonded covered stents compared to bare metal stents in lesions ≥20cm and for all lesions in the treatment per protocol analysis. “In the intention-to-treat analysis for all lesions, which however was diluted by 8.5% major protocol violations, the difference was not significant,” they wrote.
In an editorial published with the study, John R Laird and Ehrin J Armstrong, from the University of California, Davis Medical Center, Sacramento, USA, stated that the VIASTAR findings confirm that the durability of femoropopliteal stenting with bare metal stents is inversely related to lesion length, while patency following implantation of the covered stent graft appears to be independent of lesion length.
“There is less certainty about the optimal treatment of short or medium length lesions. Newer bare metal stents, drug-eluting stents, drug-eluting balloons, and atherectomy devices have all shown promise for these shorter lesions,” they wrote. They said that another question is whether drug-eluting stents can provide comparable results to an ePTFE-covered stent in these longer lesions. “Perhaps covering a stent with an anti-restenotic drug is as effective as an ePTFE barrier,” they concluded.
