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This feasibility study aims to evaluate a potential of the optical coherence tomography (OCT) to characterize stent induce injury in-vivo with adapted Gunn's score.
The frame-by-frame OCT imaging analysis (C7-XR) of the Focus NP cobalt based alloy (L605) drug-eluting stent (Envision, India - Erasmus MC, the Netherlands) was performed at this study (n = 2/50, cohort B). Three injury scores were measured with QCU-CMS software: the “deep injury” Schwartz score, the “media compression” score of Waale, and modified score of Gunn.
1017 frames and 6323 struts were analyzed. We revealed 1939 (30.62%) malapposed and 649 invisible (10.26%) struts. 3735 (59.07%) struts were investigated by adapted Gunn's injury score which was constructed as: (0) strut on intima without compression of tissues; (1) strut within intima; (2) strut within intima, but with significant compression of media; (3) strut within media with signs of rupture of internal elastic lamina (IEL); (4) signs of rupture of external elastic lamina (EEL). The interpretation of the injury score was infeasible in 623 (9.85%) struts due to invisibility of IEL and EEL. Arterial stretch and deep injury occurred in 1244 (33.31%) vs 458 (12.26%) of struts respectively, producing neointima (per cent neointimal hyperplasia area 15.52% vs 60.11%, p<0.05) with no difference between scores.
The adaptation of Gunn's injury score is the optimal candidate for OCT-guided analysis which is feasible in more than 80% of cases.