Serial Assessment by Optical Coherence Tomography of Early and Late Vascular Responses After Implantation of an Absorbable-Coating Sirolimus-Eluting Stent (from the First-in-Human DESSOLVE I Trial)

The initial enthusiasm caused by the potent antirestenotic effect of early generation drugeluting stents was recently plagued by concerns regarding their safety profile. Investigators worldwide were stimulated, therefore, to seek for improvement in drug-eluting stent technology, such as eliminating their permanent polymer blamed for vascular inflammation and delayed healing. Optical coherence tomography (OCT) assessments of stent-vessel interactions are used as a surrogate for vessel healing after DES implantation. Herewith, we report serial OCT assessments of vascular reactions to the implantation of a novel absorbable polymer sirolimus-eluting stent (MiStent). In total, 30 patients were included. At 4-, 6-, and 8-month follow-up, different groups of 10 patients underwent OCT imaging, whereas all the patients had OCT assessments scheduled at 18-month follow-up. A total of 13,569 stent struts were analyzed. Low rates of uncovered (14.34 – 15.35%, 6.62 – 10.93%, 3.51 – 2.87%, and 0.84 – 1.15%, respectively, p <0.05 for 8- vs 18-month follow-up) and malapposed (3.74 – 7.35%, 3.15 – 6.13%, 0.48 – 0.56%, and 0.09 – 0.28%, respectively, p [ NS) stent struts coupled with thin and increasingly homogenous neointimal proliferation were demonstrated. Neointimal area increased from 4- to 8-month follow-up (0.46 – 0.29 and 1.12 – 0.73 mm 2 , respectively, p <0.05), whereas no “late catch up” was demonstrated at 18-month follow-up (1.28 – 0.66 mm 2 ,p [ NS vs 8-month follow-up). Early tissue maturation and reduction of low signal intensity tissue covering stent struts (8.8%, 3.1%, 0.3%, and 0%, respectively, p <0.05 for 4- vs 8-month follow-up comparison) were revealed by optical density analysis. In addition, high rates of strut coverage overlying the ostia of side branches without proliferative pattern were demonstrated. In conclusion, this comprehensive OCT analysis depicted favorable absorbable polymer sirolimus-eluting stentevessel interactions up to 18-month follow-up. 2013 Elsevier Inc. All rights reserved. (Am J Cardiol 2013;112:1557e1564) Pathologic investigations suggested that delayed healing, characterized by inflammatory infiltrate and fibrin deposition in vessels treated with drug-eluting stents (DES), is associated with an increased risk of stent thrombosis 1,2 ; therefore, substantial efforts have been devoted to increase DES safety while preserving its antiproliferative efficacy. 3,4 Intravascular optical coherence tomography (OCT) assessments of stent-vessel interactions have been used in vivo as surrogate end points to evaluate the healing process after DES implantation. 3e5 The novel absorbable polymer sirolimus-eluting stent (APSES) composed of thin (64 mm) cobalt-chromium struts (MiStent