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The interwoven nitinol stent design, Supera (Abbott Vascular) has been shown to have superior radial strength and fracture resistance as compared to traditional nitinol stents, resulting in higher patency rates at 6 and 12 months. Recently, a single-center study, SAKE, of consecutive real-world patients at our institution revealed a primary patency rate of 96.9% at 6 months and 85.8% at 12 months based on clinical need for intervention. However, detailed sub-analysis of the SUPERB trial, revealed variances in patency based on compression or elongation of the stent during deployment. We set out to evaluate the patency of the stent within the SAKE study based on these deployment characteristics.
We retrospectively evaluated the medical charts of 80 patients (98 limbs) with Rutherford class 2-5 symptoms who received SUPERA stents in the SFA and/or popliteal artery for high-grade obstructive disease and/or chronic total occlusion from March 2010 through May 2011 as part of the SAKE study. We identified 76 limbs that met criteria for adequate evaluation of compression and elongation of the stent(s) during deployment. These patients were followed for patency (primary endpoint) and the need for re-intervention (secondary endpoint) over a mean follow up of 15 months. Vascular complications including hematoma, bleeding, and amputation were monitored for safety endpoints. Compression/Elongation was defined as follows based on previous sub-analyses: Moderate Compression (-40 to -21%); Minimal Compression (-20 to -11%); Nominal (-10 to 10%); Minimal Elongation (11 to 20%); Moderate Elongation (21 to 40%); and Severe Elongation (>40%). Clinical significance of findings were determined using analysis of variance (ANOVA) or t-test.
Of 80 patients that received Supera stents, there is a linear correlation between primary patency and stent elongation or compression at 15 month follow up. Best patency rates (85.19% primary patency and 92.59% assisted primary patency) and lowest reintervention rates (14.8%) were achieved with stent compression, followed by nominal deployment or minimal elongation, and worst outcomes (64.71% primary patency; 82.35% assisted primary patency; and 35.3% reintervention) with stent elongation to moderate or severe degree.
Patency rates and reintervention rates are variable based on deployment characteristics of the Supera stent. Best outcomes are achieved with compression of the stent during deployment.