In Vivo Optical Coherence Tomography of Very Late Drug-Eluting Stent Thrombosis Compared With Late In-Stent Restenosis

Abstract

Background: Autopsy findings have suggested delayed arterial healing as a primary cause of very late stent thrombosis (VLST) after drug-eluting stent (DES) implantation. Methods and Results: Optical coherence tomography of DES-treated lesions that developed VLST (n=6) was compared with that of DES-treated lesions that developed late in-stent restenosis (L-ISR: n=32) among patients with recurrent ischemia >1 year after DES implantation (mean, 37±17 months), and with the stented segment without any evidence of VLST or L-ISR (no-event: n=20; mean, 38±19 months). The proportion of uncovered and malapposed struts in each stented segment was evaluated. A total of 961 frames, 9,763 struts were analyzed. The proportion of uncovered struts was higher in the VLST group than in the L-ISR group and the no-event group (29.2±22.8%, 7.9±9.7%, and 7.6±8.0%, respectively; P=0.0002). The proportion of malapposed struts was higher in the VLST group than in the no-event group (7.3±8.7% vs 1.1±2.4%, P=0.01). Two patients in the VLST group had lower rates of uncovered and malapposed struts, but this involved lipid-laden-like neointima with disruptions. Conclusions: Delayed neointimal coverage and incomplete stent apposition were frequently observed in the DES-treated lesions that developed very late thrombosis. Lipid-laden-like neointima with disruption within the DES may be another possible mechanism for very late thrombosis. (Circ J 2012; 76: 390-398)