Favorable early vessel healing after everolimus-eluting stent implantation: 3-, 6-, and 12-month follow-up of optical coherence tomography

Healing and stent coverage with the new ultrathin sirolimus-eluting stent with abluminal biodegradable polymer

BACKGROUND

Genoss drug-eluting stent (DES) (Genoss Company Limited) is a new ultrathin sirolimus-eluting stent with an abluminal biodegradable polymer and a cobalt-chromium platform.

AIMS

The aim of this study was to evaluate vascular healing and neointimal coverage after implantation of the Genoss DES using optical coherence tomography (OCT) 6 months postimplantation.

METHODS

From August 22, 2019 to June 17, 2020, this multicenter, observational, investigator-initiated study enrolled 20 patients who underwent OCT examination 6 months after Genoss DES implantation and provided informed consent. An analyst, blinded to the patients' and procedural information analyzed OCT images at an independent core laboratory.

RESULTS

Of the 20 patients, 19 with 27 stents in 21 lesions from 21 vessels were included in the analysis, while one patient withdrew consent and was unwilling to undergo follow-up OCT. OCT analysis was performed 204.4 ± 31.9 days after Genoss DES implantation. A total of 4285 stent struts from 661 cross-sections were analyzed. Strut tissue coverage was observed in 98.7 ± 4.3% of struts, with 0.1 ± 1.2% malapposed struts per lesion. The mean thickness of neointimal hyperplasia (NIH) on the covered struts was 0.12 ± 0.04 mm.

CONCLUSIONS

Six months after stent implantation, most Genoss DES struts were covered with a thin layer of NIH that was evenly distributed along the stent length. This pilot study evaluated the outcomes of 6 months dual antiplatelet therapy in the context of ultrathin strut stents, providing insight into developing ethical standards and a scientific foundation for conducting an adequately designed clinical trial.

Healing and early stent coverage after ultrathin strut biodegradable polymer-coated sirolimus-eluting stent implantation: SiBi optical coherence tomography study

AIMS

The aim of SiBi study was to evaluate the early vascular healing and neointimal coverage after implantation of ultrathin (60 μm) biodegradable polymer-coated Tetriflex (Sahajanand Medical Technologies Pvt. Ltd., Surat, India) sirolimus-eluting stent (SES) using optical coherence tomography (OCT) at 4 to 6 weeks after implantation.

METHODS

SiBi was a single-center, observational, investigator-initiated study. From January 15, 2018 to April 15, 2018, total 29 consecutive patients who had consented and underwent OCT examination at 4-6 weeks after Tetriflex SES implantation were enrolled. All OCT images were analyzed at an independent core laboratory by analysts who were blinded to patient and procedural information.

RESULTS

Of 29 patients, four patients were excluded, as those OCT images were technically inadequate for analysis. Therefore, 25 patients were included in final OCT analysis. Average OCT analysis was performed after 35.3 ± 5 days of Tetriflex implantation. Total 14,024 stent struts in 1,520 cross sections were analyzed. Strut tissue coverage was observed in 91.26 ± 5.53% of struts and malapposed struts were seen in 0.89 ± 1.67%. The mean neointimal hyperplasia (NIH) thickness on the covered struts was 50 ± 30 μm.

CONCLUSION

A large percentage of struts were found to be covered with thin layer of NIH evenly distributed along the stent length at around 1 month from stent implantation. The results of this pilot study serve as ethical and scientific backbone to conduct an adequately powered clinical trial to evaluate outcomes of short dual-antiplatelet therapy in context of ultrathin strut stent.

Impact of the Antithrombotic Effects of Prasugrel on Mid-Term Vascular Healing in Acute Coronary Syndrome vs. Stable Coronary Artery Disease

BACKGROUND

The impact of antiplatelet drug effects on mid-term local arterial responses following percutaneous coronary intervention (PCI) remains uncertain. We evaluated the impact of the platelet reactivity of prasugrel on mid-term vascular healing between acute coronary syndrome (ACS) and stable coronary artery disease (CAD).Methods and Results:We conducted a prospective, 12-center study in 125 patients with ACS and 126 patients with stable CAD who underwent PCI with an everolimus-eluting stent (EES) and received dual antiplatelet therapy (DAPT) with prasugrel and aspirin. Serial optical coherence tomography (OCT) was performed immediately after PCI and at the 9-month follow-up to assess the association of P2Y₁₂reaction units (PRU) with the frequency of malapposed or uncovered struts and intrastent thrombi (IST). The incidence of abnormal mid-term OCT findings did not different between the ACS and CAD arms, regardless of clinical presentation, except that uncovered struts were more frequent in the ACS than CAD arm. PRU at PCI was significantly associated with the frequency of IST at follow-up, but not with uncovered and malapposed struts. PRU at PCI was the only independent predictor of IST detected at follow-up (odds ratio 1.009).

CONCLUSIONS

In patients undergoing EES implantation and receiving prasugrel, achieving an adequate antiplatelet effect at the time of stent implantation may regulate thrombus formation throughout the follow-up period.

Vascular responses to coronary calcification following implantation of newer-generation drug-eluting stents in humans: impact on healing

AIMS

Vascular calcification is routinely encountered in percutaneous coronary intervention (PCI) and severe coronary calcification is a known predictor of in-stent restenosis and stent thrombosis. However, the histopathologic mechanisms behind such events have not been systematically described.

METHODS AND RESULTS

From our registry of 1211 stents, a total of 134 newer-generation drug-eluting stents (DES) (Xience, Resolute-Integrity, PROMUS-Element, and Synergy) with duration of implant ≥30 days were histologically analysed. The extent of calcification of the stented lesions was evaluated radiographically and divided into severe (SC, n = 46) and non-severely calcified lesions (NC, n = 88). The percent-uncovered struts per section {SC vs. NC; median 2.4 [interquartile range (IQR) 0.0-19.0] % vs. 0.0 (IQR 0.0-4.6) %, P = 0.02} and the presence of severe medial tears (MTs) (59% vs. 44%, respectively, P = 0.03) were greater in SC than NC. In addition, SC had a higher prevalence of ≥3 consecutive struts lying directly in contact with surface calcified area (3SC) (52% vs. 8%, respectively, P < 0.0001). Multivariate analysis demonstrated that sections with duration of implantation ≤6 months [odds ratio (OR): 7.7, P < 0.0001], 3SC (OR: 6.5, P < 0.0001), strut malapposition (OR: 5.0, P < 0.0001), and lack of MTs (OR: 2.5, P = 0.0005) were independent predictors of uncovered struts. Prevalence of neoatherosclerosis was significantly lower in SC than that of NC (24% vs. 44%, P = 0.02).

CONCLUSION

Severe calcification, especially surface calcified area is an independent predictor of uncovered struts and delayed healing after newer-generation DES implantation. These data expand of knowledge of the vascular responses of stenting of calcified arteries and suggests further understand of how best to deal with calcification in patients undergoing PCI.

Comparison of serial optical coherence tomography imaging following aggressive stent expansion technique: insight from the MECHANISM study

To compare early vascular healing following cobalt-chromium everolimus-eluting stent (CoCr-EES) implantation between groups with or without aggressive stent expansion in patients treated by CoCr-EES for stable coronary artery disease (CAD). Seventy-one stable CAD lesions underwent CoCr-EES implantation and analysis of serial optical coherence tomography (OCT) images obtained post-procedure and at early-term (1- or 3-month) follow-up. The endpoints of this study were neointimal thickness at the time of 1- or 3-month OCT and presence and healing of stent edge dissection. Aggressive stent expansion was defined as a lesion complying with ILUMIEN III sizing protocol; that is, external elastic lamina (EEL) diameter minus maximum balloon diameter ≤ 0.25 mm.  Comparing groups with and without aggressive stent expansion, median neointimal thickness at 1 and 3 months after CoCr-EES implantation was similar (1 month: 0.031 mm vs. 0.041 mm, respectively, p = 0.27; 3 months: 0.036 mm vs. 0.040 mm, respectively, p = 0.84). Regarding stent edge findings, the presence of any stent edge dissection immediately after percutaneous coronary intervention was also similar between the groups (25% vs. 15%, respectively; p = 0.30) and most stent edge dissections resolved completely within 3 months, regardless of location or dissection severity. After 1 year, no clinically driven target lesion revascularization or stent thrombosis was observed in either cohort. Even after aggressive stent expansion, early neointimal proliferation appeared modest with CoCr-EES implantation, and most stent edge dissections had resolved by 3 months. These findings may support the feasibility of EEL-based sizing by pre-stenting OCT.