Early vessel healing after implantation of biodegradable-polymer and durable-polymer drug-eluting stent: 3-month angioscopic evaluation of the RESTORE registry

Angioscopic Comparison of Early- and Mid-Term Vascular Responses Following Treatment of ST-Elevation Acute Myocardial Infarction With Biodegradable vs. Durable Polymer Everolimus-Eluting Stents - A Prespecified Subanalysis of the MECHANISM AMI RCT

BACKGROUND

The vessel healing process after implantation of biodegradable polymer (BP) and durable polymer (DP) everolimus-eluting stent (EES) in ST-elevation myocardial infarction (STEMI) lesions remains unclear.

METHODS AND RESULTS

We conducted a multicenter prospective randomized controlled trial to compare early (2 weeks) and mid-term (12 months) vascular responses after implantation of BP-EES vs. DP-EES in STEMI patients. In this prespecified subanalysis, serial coronary angioscopy (CAS) analysis was performed in 15 stents in the BP-EES arm (n=10 patients) and 14 stents in the DP-EES arm (n=10 patients). At the 2-week follow-up, there was no significant difference in the estimated marginal means of the neointimal coverage grade (primary endpoint) between the 2 arms (mean [±SE] 0.00±0.00 in both arms; P>0.999). There were no significant differences between the BP-EES and DP-EES groups in the yellow color grade (1.046±0.106 vs. 0.844±0.114, respectively; P=0.201) or the presence of thrombus (77.8% vs. 88.8%, respectively; P=0.205). At 12 months, competent strut coverage, defined as yellow color grade ≤1, no thrombus, and a neointimal coverage grade ≥1 was achieved more frequently in the BP-EES than DP-EES arm (85.2% vs. 53.1%; adjusted odds ratio 2.11 [95% confidence interval 1.26-3.53]; P=0.023).

CONCLUSIONS

Neointimal coverage 2 weeks after implantation of BP-EES and DP-EES in STEMI lesions was comparable on CAS evaluation. However, at 1 year, BP-EES was independently associated with competent strut coverage.

Developing small-diameter vascular grafts with human amniotic membrane: long-term evaluation of transplantation outcomes in a small animal model

While current clinical utilization of large vascular grafts for vascular transplantation is encouraging, tissue engineering of small grafts still faces numerous challenges. This study aims to investigate the feasibility of constructing a small vascular graft from decellularized amniotic membranes (DAMs). DAMs were rolled around a catheter and each of the resulting grafts was crosslinked with (a) 0.1% glutaraldehyde; (b) 1-ethyl-3-(3-dimethylaminopropyl) crbodiimidehydro-chloride (20 mM)-N-hydroxy-succinimide (10 mM); (c) 0.5% genipin; and (d) no-crosslinking, respectively. Our results demonstrated the feasibility of using a rolling technique followed by lyophilization to transform DAM into a vessel-like structure. The genipin-crosslinked DAM graft showed an improved integrated structure, prolonged stability, proper mechanical property, and superior biocompatibility. After transplantation in rat abdominal aorta, the genipin-crosslinked DAM graft remained patent up to 16 months, with both endothelial and smooth muscle cell regeneration, which suggests that the genipin-crosslinked DAM graft has great potential to beimplementedas a small tissue engineered graft for futurevasculartransplantation.

Early vascular healing after neXt-generation drug-eluting stent implantation in Patients with non-ST Elevation acute Coronary syndrome based on optical coherence Tomography guidance and evaluation (EXPECT): study protocol for a randomized controlled trial

Background

There is limited evidence about vessel wall healing response following implantation of next-generation drug-eluting stents (DES) in patients admitted with a non-ST elevation acute coronary syndrome (NSTE-ACS). Cumulative data indicate that optical coherence tomography (OCT) imaging can optimize percutaneous coronary intervention results and expedite stent endothelialization in the general population but there is lack of data in NSTE-ACS patients.

Methods

The EXPECT study is an investigator-initiated, prospective, randomized trial to assess early vascular healing response following next-generation DES implantation in patients admitted with NSTE-ACS based on OCT guidance and evaluation. Sixty patients are randomized at 1:1:1 ratio to OCT-guided percutaneous coronary intervention (PCI) with 3-month follow-up OCT imaging (O3 group, n = 20), to angiography-guided PCI with 3-month follow-up OCT imaging (A3 group, n = 20) and to angiography-guided PCI with 6-month follow-up OCT imaging (A6 group, n = 20). The primary endpoint of the study is stent strut coverage rate at 3- or 6- month follow-up in the studied groups. The secondary endpoints of the study include OCT imaging endpoints, clinical endpoints, and molecular biology endpoints at the different time points. The clinical endpoints comprised of major cardiovascular adverse events and individual components. The molecular biology endpoints comprised of lipid levels and the levels of inflammatory indicators.

Discussion

The findings of the EXPECT study are anticipated to provide novel insights into vessel wall healing in NSTE-ACS population following implantation of next-generation DES, underscore the value of OCT imaging in expediting strut coverage in this setting, and explore the potential of an early discontinuation of dual antiplatelet therapy (DAPT) in this population.

Clinical Trial Registration

ClinicalTrials.gov, NCT04375319.

Vascular healing in high-bleeding-risk patients at 3-month after everolimus-eluting stent versus biolimus A9-coated stent implantation: insights from analysis of optical coherence tomography and coronary angioscopy

The prevalence of high-bleeding-risk (HBR) patients who undergo coronary stenting has been reported as 20-40%. This study sought to assess vascular healing in HBR patients by coronary angioscopy (CAS) and optical coherence tomography (OCT). We prospectively analyzed 38 HBR patients with coronary artery disease who successfully underwent everolimus-eluting stent (EES) implantation (20 patients, 23 lesions) or drug-coated stent (DCS) implantation (18 patients, 18 lesions). Follow-up coronary angiography, CAS, and OCT were planned at 3 months after the procedure. The clinical characteristics and inclusion criteria of HBR were comparable between groups. CAS analysis showed that mean yellow color grade was significantly higher with EES than with DCS (1.33 [1.0, 1.67] vs. 1.0 [0.67, 1.5]; P = 0.04). In contrast, OCT analysis demonstrated that most struts in both groups were well-apposed struts with neointimal coverage (93.9% each; P = 1.00), and percentages of the mean neointimal area were comparable between EES and DCS (4.4 ± 3.5 mm² vs. 4.5 ± 4.1 mm²; P = 0.91). The frequency of uncovered struts was significantly lower with EES than with DCS (2.4% vs. 5.3%; P < 0.001), whereas the frequency of malapposed struts was significantly higher with EES than with DCS (3.5% vs. 0.8%; P < 0.001). During follow-up, no stent thrombosis or major bleeding complications were encountered in either group. Among HBR patients, both EES and DCS demonstrated good vascular healing at 3-month follow-up with some different features in CAS and OCT assessments.

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.

Impact of Neointimal Condition and Platelet Reactivity on Intrastent Thrombus at Long-Term Follow-up After 2nd- and 3rd-Generation Drug-Eluting Stent Implantation - Insights From a Coronary Angioscopy and Pharmacodynamic Study

BACKGROUND

Although the incidence of very late stent failure (VLSF) is reduced with newer generation drug-eluting stent (DES), the mechanism of VLSF has not been fully explored.Methods and Results:This study evaluated both local vascular healing using coronary angioscopy and systemic factors determined by platelet reactivity at long-term follow-up after 2nd- and 3rd-generation DES implantation in patients with acute coronary syndrome. Coronary angioscopy was performed to assess neointimal coverage (NIC), yellow color (YC) grade and presence of thrombus. The obtained findings were compared with 2nd- and 3rd-DES. Platelet aggregation was assessed by light transmittance aggregometry. 100 consecutive patients were prospectively enrolled: 2nd- (n=50) and 3rd-DES (n=50). 3rd-DES patients had significantly higher NIC grade and lower YC grade compared with 2nd-DES. The presence of thrombus was tended to be lower with 3rd-DES than with 2nd-DES (8% vs. 18%, P=0.11). Patients with thrombus had significantly higher maximum platelet aggregation and higher prevalence of high on-treatment platelet reactivity (HPR) than those without thrombus. Multivariable analysis showed stent strut exposure and HPR as independent predictors of thrombus.

CONCLUSIONS

Newer generation DES contribute to better vascular healing depending on the degree of neointimal coverage. In addition to local factors at the stented lesion, systemic factors such as degree of platelet reactivity might also contribute to VLSF.