The effect of coronary artery plaque composition, morphology and burden on Absorb bioresorbable vascular scaffold expansion and eccentricity - A detailed analysis with optical coherence tomography

Aims: Suboptimal stent expansion correlates with adverse cardiac events. There is limited information regarding Absorb bioresorbable vascular scaffold (BVS) expansion characteristics. Optical coherence tomography (OCT) allows for high-resolution assessment of plaque morphology, composition and assessment of BVS expansion. This study evaluates coronary plaque composition, morphology and burden and their effect on Absorb BVS expansion using OCT.

Methods and results: Two thousand three hundred and thirty four frames totalling 462.6 mm of BVS from twenty OCT-guided BVS implantations were examined. 200 μm longitudinal cross-sections of each BVS were analysed for lumen contours and plaque characteristics. The relationship between each plaque characteristic and scaffold expansion index (SEI) or scaffold eccentricity index (SEC) was analysed by repeated measures ANOVA. Forty-four fibrous and 265 calcific plaques were identified. Lower SEI was significantly (p<0.001) associated with greater calcific plaque (CP) area (mean SEI 78.9% vs. 80.0%), thickness (78.5% vs. 80.4%) and lower CP depth (78.3% vs. 80.2%). Lower SEC was significantly (p<0.001) associated with greater fibrous plaque (FP) area (0.84 vs. 0.85), thickness (0.83 vs. 0.86), arc angle (0.84 vs. 0.85), greater CP area (0.83 vs. 0.86), CP thickness (0.83 vs. 0.86), CP angle (0.84 vs. 0.85) and lower CP depth (0.84 vs. 0.85). Greater FP area was associated with greater SEI (81.0% vs. 80.0%, p<0.001), even after adjustment for target vessel size. Greater FP angle (80.7% vs 78.3%, p<0.001) and quadrants occupied were also associated (80.0% vs 78.5%, p<0.002) with greater SEI.

Conclusion: BVS expansion and eccentricity are significantly impacted by plaque composition, morphology and burden.