Neointimal characteristics comparison between biodegradable-polymer and durable-polymer drug-eluting stents: 3-month follow-up optical coherence tomography light property analysis from the RESTORE registry

Comparison of 6-month vascular healing response after bioresorbable polymer versus durable polymer drug-eluting stent implantation in patients with acute coronary syndromes: A randomized serial optical coherence tomography study

Objectives

This study was conducted to use optical coherence tomography (OCT) to compare vascular healing between bioresorbable polymer (BP) and durable polymer (DP) everolimus‐eluting stents (EES) in patients with acute coronary syndromes (ACS).

Background

Whether BP‐EES induce better vascular healing compared to contemporary DP‐EES remains controversial, especially for ACS.

Methods

In this prospective, randomized, non‐inferiority trial, we used OCT to compare 6‐month vascular healing in patients with ACS randomized to BP versus DP‐EES: percent strut coverage (primary endpoint, non‐inferiority margin of 2.0%) and neointimal thickness and percent neointimal hyperplasia (NIH) volume. As an exploratory analysis, morphological factors related to the endpoints and the effect of underlying lipidic plaque on stent healing were evaluated.

Results

A total of 104 patients with ACS were randomly assigned to BP‐EES (n = 52) versus DP‐EES (n = 52). Of these, 86 patients (40 BP‐EES and 46 DP‐EES) were included in the final OCT analyses. Six‐month percent strut coverage of BP‐EES (83.6 ± 11.4%) was not non‐inferior compared to those of DP‐EES (81.6 ± 13.9%), difference 2.0% (lower 95% confidence interval‐2.6%), p_{non‐inferiority} = 0.07. There were no differences in neointimal thickness 70.0 ± 33.9 μm versus 67.2 ± 33.9 μm, p = 0.71; and percent NIH volume 7.5 ± 4.7% versus 7.3 ± 5.3%, p = 0.85. By multivariable linear regression analysis, stent type was not associated with percent strut coverage or percent NIH volume; however, percent baseline embedded struts or stent expansion was positively associated with percent NIH volume. Greater NIH volume was observed in lipidic compared with non‐lipidic segments (8.7 ± 5.6% vs. 6.1 ± 5.2%, p = 0.005).

Conclusions

Six‐month strut coverage of BP‐EES was not non‐inferior compared to those of DP‐EES in ACS patients. Good stent apposition and expansion were independently associated with better vascular healing.

Comparable neointimal healing in patients with stable coronary lesions and acute coronary syndrome: 3-month optical coherence tomography analysis

We aimed to assess a possible difference of the neointimal coverage status and its quality after implantation of the current-generation metallic stents in patients with acute coronary syndrome (ACS) vs. stable coronary lesions (non-ACS). We comprehensively analyzed three prospective single-center observational studies RESTORE (UMIN000033009), HEAL-BioFreedom (UMIN000029692), and HEAL-BioFreedom ACS (UMIN000034769). All patients who received successful optical coherence tomography (OCT) examination at planned 3-month follow-up after stent implantation were analyzed. Study population was divided into two groups, ACS vs. non-ACS groups. We evaluated standard OCT variables, coverage percent, and the quantitative light property values including light intensity, attenuation, and backscatter of neointima. A total of 177 lesions from 154 patients (ACS 44 lesions vs. non-ACS 133 lesions) were analyzed. At 3-month follow-up, coverage percent (ACS 91.5  ±  9.5% vs. non-ACS 91.8  ±  9.0%, P = 0.722) and neointimal thickness (ACS 59.5  ±  32.3 µm vs. non-ACS 58.2  ±  32.3 µm, P = 0.760) did not significantly differ. Light property values were similar between both groups (light intensity 159.29  ±  72.20 vs. 159.45   ± 63.78, P = 0.654; light attenuation 0.88  ±  0.26 vs. 0.87   ±  0.24 m^-1, P = 0.988; backscatter 4.86   ±  0.58 vs. 4.83   ±  0.57, P = 0.812). The similarity of the neointimal quality in ACS and non-ACS patients was consistent across the 6 different types of current-generation metallic stents (P for interaction  > 0.05). Our findings suggested the comparable neointimal characteristics 3 months after implantation of the current-generation metallic stents in patients with ACS and stable coronary lesions by quantitative OCT methodology.

Quantitative Validation of the Coronary Angioscopic Yellow Plaque with Lipid Core Burden Index Assessed by Intracoronary Near-Infrared Spectroscopy

Aim: We aimed to validate the subjective and qualitative angioscopic findings by the objective and quantitative near-infrared spectroscopic (NIRS) assessment to compensate each other’s drawbacks.

Methods: This is a single-center prospective observational study. Patients undergoing a planned follow-up coronary angiography after percutaneous coronary intervention were prospectively enrolled from January 2018 to April 2019. The major three vessels were examined by NIRS-intravascular ultrasound, followed by coronary angioscopic evaluation. Yellow color grade on angioscopy was classified into four grades (0, white; 1, slight yellow; 2, yellow; and 3, intensive yellow) at a location of maximal lipid core burden index over 4 mm [LCBI (4)] on NIRS in each vessel.

Results: A total of 95 lesions in 44 patients (72.6±6.7 years, 75% male) were analyzed. LCBI (4) was significantly different among different yellow color grades by coronary angioscopy (ANOVA, p ＜0.001). Positive correlation was found between angioscopic yellow color grade and LCBI (4) (beta coefficient 164.8, 95% confidence interval 122.9–206.7; p ＜0.001). The best cutoff value of LCBI (4) to predict the presence of yellow plaque (yellow color grade ≥ 2) was 448 (sensitivity 79.3%, specificity 69.7%, C-statistic 0.800, 95% confidence interval 0.713–0.887, p ＜0.001).

Conclusion: The qualitative angioscopic assessment was objectively validated by the quantitative NIRS evaluation, which would be helpful for the reinterpretation of the existing evidences of both imaging modalities.