A comparison of covered vs bare expandable stents for the treatment of aortoiliac occlusive disease

Objective This trial was conducted to determine if covered stents offer a patency advantage over bare-metal stents in the treatment of aortoiliac arterial occlusive disease. Methods The Covered Versus Balloon Expandable Stent Trial (COBEST), a prospective, multicenter, randomized controlled trial, was performed involving 168 iliac arteries in 125 patients with severe aortoiliac occlusive disease who were randomly assigned to receive a covered balloon-expandable stent or bare-metal stent. Patient demographic data, clinical signs and symptoms, TransAtlantic Inter-Society Consensus (TASC) classification, and preprocedure and postprocedure ankle-brachial index measurements were recorded. The primary end points included freedom from binary restenosis and stent occlusion of the treated area, as determined by ultrasound imaging or quantitative visual angiography, or both. Postprocedural follow-up was at 1, 6, 12, and 18 months. Results Aortoiliac lesions treated with a covered stent were significantly more likely to remain free from binary restenosis than those that were treated with a bare-metal stent (hazard ratio [HR], 0.35; 95% confidence interval (CI), 0.15-0.82; P = .02). Freedom from occlusion was also higher in lesions treated with covered stents than in those treated with a bare-metal stent (HR, 0.28; 95% CI, 0.07-1.09); however, this did not reach statistical significance ( P = .07). Subgroup analyses demonstrated a significant difference in freedom from binary restenosis for covered stents in TASC C and D lesions compared with a bare stent (HR, 0.136; 95% CI, 0.042-0.442). This difference was not demonstrated for TASC B lesions (HR, 0.748; 95% CI, 0.235-2.386). Conclusions COBEST demonstrates covered and bare-metal stents produce similar and acceptable results for TASC B lesions. However, covered stents perform better for TASC C and D lesions than bare stents in longer-term patency and clinical outcome.