Serial comparison of neointimal hyperplasia between the thin strut MiStent with microcrystalline sirolimus and the durable polymer coated everolimus-eluting Xience stent : 6- and 24-month results of DESSOLVE III OCT sub-study

AIMS: DESSOLVE III OCT sub-study compared serially neointimal hyperplasia volume obstruction (%VO) between the thin strut MiStent with early polymer elimination and 9-month sustained drug release from microcrystalline sirolimus and the durable polymer coated everolimus-eluting Xience stent at 6 and 24 months after implantation. METHODS AND RESULTS: The efficacy endpoint was %VO calculated as abluminal neointimal volume/stent volume. Thirty-six patients (MiStent 16 patients, 16 lesions, Xience 20 patients, 22 lesions) underwent serial OCT evaluation at both 6 and 24 months. At 6 months, mean abluminal %VO was significantly lower in the MiStent group than in Xience group (14.54±3.70% vs. 19.11±6.70%; p=0.011), whereas the difference in %VO between the two groups decreased at 24 months (20.88±5.72% vs. 23.50±7.33%; p=0.24). There was no significant difference in percentage malapposed struts and percentage uncovered struts between the two groups at both time points. CONCLUSIONS: In the serial comparative OCT analysis of the MiStent vs. the Xience, the MiStent showed a more favourable efficacy for preventing neointimal formation with comparable strut tissue coverage, as compared with the Xience at 6 months, but this difference in %VO decreased at 24 months so that the difference in neointima at 24 months was no longer significant.