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.