Effect of Plaque Composition, Morphology, and Burden on DESolve Novolimus-Eluting Bioresorbable Vascular Scaffold Expansion and Eccentricity - An Optical Coherence Tomography Analysis.

OBJECTIVE

This study of patients treated with novolimus-eluting bioresorbable scaffold (BRS) investigated the impact of plaque burden on the acute mechanical performance of the BRS and the short-term outcome.

METHODS

A total of 15 patients were enrolled. The following parameters were derived from optical coherence tomography (OCT) during the final pullback: mean and minimum area, residual area stenosis, incomplete strut apposition, tissue prolapse, scaffold expansion index (SEI), scaffold eccentricity index (SEC), symmetry index, strut fracture, and edge dissection. Fibrous plaque (FP) and calcific plaque (CP) characteristics were measured at each 200 μm longitudinal cross-section. The patients were divided into two groups based on their medians of the respective plaque characteristics.

RESULTS

OCT analysis showed a lumen area of 11.4 ± 1.9 mm2 and a scaffold area of 11.5 ± 2.1 mm2. The mean eccentricity index overall was 0.65 ± 0.16 and mean symmetry index 0.39 ± 0.25. Statistically, scaffold expansion was not significantly influenced by a greater plaque burden as represented by greater CP area (SEI in group with CP area <0.52 mm2 84.1% vs. SEI of 86.6% in group with CP area ≥0.52 mm2, p = 0.06), thicker CP (85.7% vs. 85.1%, p = 0.06), greater CP arc angle (88.0% vs. 81.7%, p = 0.08), and CP being closer to the lumen (84.2% vs. 86.5%, p = 0.08). Scaffold expansion was also not significantly influenced by FP burden. The eccentricity of the implanted scaffolds was not dependent on the CP burden. On the other hand, a greater FP burden favoured a lower eccentricity index, indicating less circular expansion. Thus, greater FP area, FP thickness, and FP arc angle resulted in a more eccentric scaffold expansion.

CONCLUSION

In contrast to previously studied BRS, the expansion and eccentricity characteristics of the novolimus-eluting scaffold did not show the strong dependency of plaque composition, morphology, and burden. As assessed by OCT, only eccentricity was significantly affected by the FP burden. A greater FP plaque arc in our cohort and device-specific properties, e.g. self-correction, may explain the lack of a relationship between plaque, expansion, and eccentricity.