Intravascular Ultrasonography Analysis of the Everolimus-Eluting Stent in Coronary Chronic Total Occlusions
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PURPOSE: Coronary artery disease (CAD) is consistently the number one cause of death for both men and women worldwide. Of the millions of patients diagnosed with CAD, approximately 1 in 5 is found to have a coronary artery that has been 100% blocked for three months or longer, representing the most formidable subset of atherosclerosis: chronic total occlusion (CTO). While drug-eluting stents have demonstrated success in patients with less severe coronary atherosclerosis, little is known about their efficacy in CTOs, which are currently managed by bare metal stents associated with high rates of restenosis. The present study aims to evaluate the effectiveness of the novel Everolimus-Eluting Stent (EES) in CTOs, using intravascular ultrasonography (IVUS) to assess restenosis. METHODS: One hundred consecutive CTO patients who were successfully treated using EES at the Dallas VAMC between 2009-2012 were enrolled in the AngiographiC Evaluation of the Everolimus-Eluting Stent in Chronic Total Occlusions (ACE-CTO trial: NCT01012869). Patients underwent follow-up angiography and IVUS imaging at 8 months and clinical follow-up for up to 12 months. The primary endpoint of this study, binary angiographic restenosis, was defined as >50% minimum lumen diameter stenosis, as assessed by 8-month follow-up quantitative coronary angiography in the treated coronary segment. The primary endpoint of the IVUS analysis was 8-month in-stent neointimal hyperplasia (NIH) volume, defined as the difference between stent and lumen volume. RESULTS: Of the 226 patients who underwent CTO percutaneous coronary intervention (PCI) during the enrollment period, 129 were eligible and 100 agreed to participate. Mean age was 64±7 years, and 99% of the patients were men. Patients had high prevalence of hypertension (91%), hyperlipidemia (90%), diabetes (47%), prior myocardial infarction (51%), and prior PCI (21%). The CTO target vessel was the right coronary artery (70%), left anterior descending artery (16%), circumflex (13%), or left main (1%). The mean number of implanted stents was 3.3±1.3, mean stent diameter was 2.8±1.1 mm, mean stent length was 85±34 mm, and 94 patients had overlapping stents. Binary angiographic restenosis was 45%. Follow-up IVUS analysis of 55 patients revealed low median minimum lumen area (3.3 mm2) and high NIH volume (103.6 mm3). CONCLUSIONS: Everolimus-eluting stent implantation in CTOs is associated with high rates of angiographic restenosis and high NIH volume, suggesting the need for novel therapeutic strategies to improve outcomes in this complex and challenging lesion subgroup.