Long-Term Follow-Up of Incomplete Stent Apposition in Patients Who Received Sirolimus-Eluting Stent for De Novo Coronary Lesions: An Intravascular Ultrasound Analysis

Background - Incomplete stent apposition (ISA) has been previously documented after sirolimus-eluting stent (SES) implantation. The aim of this study was to investigate the long-term intravascular ultrasound (IVUS) findings of ISA in patients who received SES. Methods and Results - A total of 13 patients who received SES and showed ISA at follow-up IVUS (follow-up I) were investigated. IVUS was performed on all of these patients 12 months later (follow-up II). Quantitative ISA area measurement was also performed at follow-up I and II. No vascular remodeling was observed in the vessel segment with ISA; external elastic membrane area was 19.4±6.6 versus 19.5±6.4 mm² at follow-up I and II, respectively. There was also no significant change in external elastic membrane area between vessel segment with ISA and without ISA (+ 1.5% versus -3.0%, respectively; P=0.27) at late follow-up. The ISA area, either including (2.5±1.7 versus 3.8±6.3 mm²; P=NS) or excluding (2.5±1.8 versus 2.4±1.7 mm²; P=NS) a single patient with aneurysm formation, was not significantly different between follow-up I and II. One patient manifested a coronary aneurysm in the stented segment at late follow-up that was probably present at the initial follow-up but masked by thrombus. It was successfully treated with a covered stent. All patients were asymptomatic, and no patient experienced late thrombotic occlusion. Conclusions - Vessel dimensions and area of ISA did not change over time, except for 1 coronary aneurysm that became apparent. ISA after implantation of a SES was not associated with adverse events at late follow-up.