Direct comparison of bioabsorbable and biodurable polymer everolimus-eluting stent in neointimal stent coverage and in-stent thrombus using high-resolution angioscope

Background/Introduction

Although second-generation drug eluting stent (DES) employing biodurable polymer drastically shortened the duration of dual antiplatelet therapy (DAPT), previous reports raised concerns that switching from DAPT to single antiplatelet therapy increased rates of subsequent stent thrombosis with time. Third-generation DES employing bioabsorbable polymer has been introduced so as not to hinder the healing process of the vessel wall, however, at present, both DES with bioabsorbable polymer and those with biodurable polymer are used in parallel. It means there is no conclusive evidence regarding pros and cons of these two types of polymers.

Purpose

This study aims to clarify how bioabsorbable polymer and biodurable polymer act on the human coronary artery by observing neointimal stent coverage (NIC) and in-stent thrombus by comparing the third-generation DES with bioabsorbable-polymer cobalt-platinum everolimus-eluting stent (BP CoPt-EES), and the second-generation DES with biodurable-polymer cobalt-chromium everolimus-eluting stent (DP CoCr-EES).

Methods

This is a multicenter observational study including 11 hospitals. We investigated 70 stents (BP CoPt-EES: 40, DP CoCr-EES: 30) of 60 cases, who underwent stent implantation followed by simultaneous observation by coronary angiography, IVUS and angioscopy within 6 to 12 months. For angioscopy, we used a recently available, high-resolution angioscope with a pixel count of 9,000 which realized both stent coverage analysis and planar thrombus detection precisely. Neointimal stent coverage was graded from G0: non coverage to G3: full coverage, and heterogeneity value of neointima was measured as the difference between maximum and minimum NIC grade.

Results

A strong relationship was observed between NIC grade and in-stent thrombus in all stents (p=0.0011), and between the heterogeneity value and stent thrombus (p=0.012). There was no statistical difference in NIC grade between BP CoPt-EES vs. DP CoCr-EES; grade 0: 0 (0.0%) vs. 2 (6.7%), grade 1: 13 (32.5%) vs. 11 (36.7%), grade 2: 6 (15.0%) vs. 6 (20.0%), grade 3: 21 (52.5%) vs. 11 (36.7%), p=0.17) and neither in the heterogeneity value of neointima (p=0.49). The ratio of stent thrombus did not reach statistical difference; 16 (40.0%) in BP CoPt-EES vs. 17 (56.7%) in DP CoCr-EES (p=0.23).

Conclusion

The existence of stent thrombus was associated with the neointimal stent coverage. There was no significant difference both in neointimal stent coverage and stent thrombus between bioabsorbable polymer cobalt-platinum EES and biodurable polymer cobalt-chromium EES after 6 to 12 months following stent deployment.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Boston Scientific JapanOvalis ltd

Serial evaluation of cardiac allograft vasculopathy after heart transplantation by dual-modality intravascular ultrasound and optical coherence tomography

Background

Cardiac allograft vasculopathy is a combination of the development of de novo plaque and the progression of donor-transmitted plaque.

Purpose

This study aimed to evaluate the development of de novo plaque and the progression of donor-transmitted plaque within 12-month after heart transplantation (HTx) using serial intravascular ultrasound (IVUS) and optical coherence tomography (OCT). The association between inflammatory cytokines and plaque progression was also examined.

Methods

We prospectively enrolled 40 recipients to conduct serial three-vessel IVUS and OCT analysis at 8-week and 12-month after HTx. De novo plaque was defined as having maximum intimal thickness (MIT) ≥0.5 mm at 12-month in the absence of donor-transmitted plaques (MIT ≥0.5 mm at 8-week). Serum cytokines were screened with a bead-based multiplex assay.

Results

A total of 13 de novo plaques (fibrous, n=10; fibroatheroma, n=3) were detected in eight recipients. Serum interleukin (IL)-31 at 8-week was associated with the development of de novo plaques (p=0.009). A total of 31 donor-transmitted plaques (fibrous, n=12; fibroatheroma, n=11; fibrocalcific, n=8) were detected in 17 recipients. Multiple regression analysis revealed that fibrous (p=0.026) and fibroatheroma (p=0.012) observed at 8-week were significantly associated with subsequent plaque progression within 12-month after HTx. ΔPlaque burden was significant higher in de novo plaque than donor-transmitted plaque (38.8% [29.6–41.2] versus 8.7% [1.3–13.6], p<0.001). The prevalence of macrophage accumulation was lower in de novo plaque than in donor-transmitted plaque (8% versus 52%, p=0.006). Serum IL-31 at 8-week was correlated with the progression of donor-transmitted plaque as well as de novo plaque (r=0.663, p=0.029) although other cytokines like IL-1β, IL-6, IL-17, and tissue necrotic factor alpha were not.

Conclusions

In de novo plaques, fibrous plaque was the most common and macrophage accumulation was rarely observed. In donor-transmitted plaque, fibrous and fibroatheroma were independent predictor for the subsequent plaque progression. Serum interleukin-31 surge at subacute phase may play pathogenic role in cardiac allograft vasculopathy.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grants-in-Aid for Scientific Research (KAKENHI)