Background: Uncovered struts are a determinant of stent failure. The impact of plaque composition and procedural factors on the occurrence, evolution, and outcomes of uncovered struts in a high-risk setting has not been investigated.
Objective: To investigate the determinants and long-term clinical impact of largely uncovered struts (LUS) in thin-struts drug-eluting stents (DES) implanted in complex lesions by intracoronary optical coherence tomography (OCT).
Methods: Ninety patients with multivessel disease undergoing staged complete revascularization were randomly assigned to bioabsorbable or durable polymer DES. OCT were serially performed during the index procedure, at 3- and 18-month follow-up, and analyzed by an independent core lab. Struts were defined uncovered by OCT if no tissue was visible above the struts. LUS were defined as ≥30% of uncovered struts at 3-month follow-up. Clinical outcomes were the occurrence of target vessel failure (TVF) and major adverse cardiac and cerebrovascular events (MACCE) at 5-year follow-up.
Results: LUS occurred in 31 patients (34.4%) regardless of stent platform. At 5 years, no differences were observed in the rate of TVF (12.7% vs. 13.4%; p = 0.91) and MACCE (23.9% vs. 24.9%; p = 0.88) between the two groups. At multivariate logistic regression, plaque rupture, mean lumen diameter, proximal reference vessel area, and maximum stent deployment pressure were independent predictors of LUS.
Conclusions: LUS are a frequent finding in complex coronary lesions treated with thin-struts DES, especially in the presence of plaque rupture. However, in this study, no significant safety signal related to LUS emerged in long-term follow-up.
Keywords: coronary artery disease; drug-eluting stents; intravascular imaging; optical coherence tomography; percutaneous coronary intervention; uncovered struts.
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