Overtime evaluation of the vascular HEALing process after everolimus-eluting stent implantation by optical coherence tomography. The HEAL-EES study

Serial evaluation of vascular responses after implantation of everolimus-eluting coronary stent by optical coherence tomography

AIM

To evaluate healing response at strut-level and cross-section level after implanting an ultra-thin strut, everolimus-eluting stent with biodegradable polymer (Tetrilimus) using optical coherence tomography (OCT) at 3 and 6 months.

METHODS

This was prospective, multi-centre, single-arm, and investigator-initiated study performed at seven Indian sites between January, 2017 and September, 2018. OCT evaluations were performed in 57 patients who underwent Tetrilimus stent implantation. Follow-up OCT was scheduled at 3 months for first 16 patients and at 6 months for 41 patients. Primary outcomes included degree of strut coverage, malapposition and thickness of neointimal hyperplasia (NIH) over covered struts.

RESULTS

Sixty one Tetrilimus stents were implanted to treat 59 lesions in 57 patients. Paired (baseline and follow-up) OCT data was available for 12 patients and 30 patients at 3 and 6 months, respectively. At 3 months, rapid early healing was indicated by 95.48% covered struts per lesion with very low (0.11 ± 0.06 mm) NIH. At 6 months, NIH accumulation was greater (0.21 ± 0.07 mm) as compared to 3 months. 99.77% of struts per lesion were covered at 6 months. There was a very symmetrical healing as shown by very low eccentricity index. There was no difference in vascular healing between stents with small to moderate size vessels (≤3.00 mm) and large size vessels (>3.00 mm).

CONCLUSION

Present study demonstrated nearly complete endothelization and low NIH accumulation at 3 and 6 months following implantation of ultra-thin strut everolimus-eluting biodegradable polymer-coated Tetrilimus stent. Moreover, though being an ultra-thin strut stent, there was no difference in vascular healing and eccentricity after implantation of the Tetrilimus stents with smaller and larger diameters.

Impact of diabetes mellitus on vascular healing process after everolimus-eluting stent implantation: An optical coherence tomography study

BACKGROUND/PURPOSE

To study the impact of diabetes mellitus (DM) on vascular healing process after implantation of everolimus-eluting stent (EES).

METHODS/MATERIALS

Data from 3 prospective studies (HEAL-EES, REVER, and RESERVOIR), including patients with EES implantation and OCT follow-up, were merged. Differences in vascular healing process assessed by OCT were compared between DM and non-DM using generalized estimating equations. Neointimal proliferation, neointimal signal pattern (high, low, and layered), and uncovered/malapposed struts were evaluated.

RESULTS

A total of 96 lesions (61 DM lesions and 35 non-DM lesions) were included. Mean OCT follow-up time was 8.9 ± 1.5 months and comparable between groups. DM were older, high frequently female and acute coronary syndrome, and received smaller stent than non-DM. No differences were observed in quantitative vascular healing process between groups. However, DM exhibited higher low and layered signal pattern neointima compared to non-DM at lesion level (p = 0.030) and cross-section level (p < 0.001). Uncovered/malapposed struts were comparable between groups.

CONCLUSIONS

Quantitative vascular healing process was comparable between groups. However, DM was significantly associated with low signal pattern, which is characteristic of focal inflammation, after EES implantation. Further study might be required to study relationship between neointimal signal pattern and clinical events.

First-in-Man Evaluation of a Sirolimus-Eluting Stent With Abluminal Fluoropolymeric/Triflusal Coating With Ultrathin Struts by OCT at 9 Months' Follow-Up: The PROMETHEUS Study

OBJECTIVES

We sought to investigate stent healing and neointimal hyperplasia with ihtDEStiny drug-eluting stent (DES) by optical coherence tomography (OCT) examination conducted 9 months after implantation.

BACKGROUND

The currently used DES present certain features that have been linked separately to their better performance in terms of efficacy and safety.

METHODS

First-in-man, prospective and multicenter study including patients treated with ihtDEStiny stent undergoing OCT examination at 9 months follow up. The ihtDEStiny stent is a sirolimus eluting stent with an oval shape ultrathin struts (68 μm) and an abluminal coating of a fluoropolymer containing the antiplatelet agent triflusal. Primary endpoint was the percentage of obstruction of the in-stent volume by the neointima.

RESULTS

In 58 patients (63 lesions) in-stent late lumen loss was 0.11 ± 0.23 mm (95% CI 0.05-0.16) with only in 6% of stents being > 0.5 mm and in-segment binary stenosis was 1.6%. In OCT mean neointima volume obstruction was 10.5 ± 6.9% with a mean neointima thickness of 110.9 ± 89.8 μm. The proportion of uncovered struts was 2.5%, malapposed struts 1.1% and malapposed/uncovered struts 0.7% and no subclinical thrombi detected. Mean incomplete stent apposition area was 0.1 ± 0.1 mm². At 12 months target lesion revascularization rate was 3% and no stent thrombosis was reported.

CONCLUSIONS

In this study the ihtDEStiny stent has shown a very low degree of neointimal proliferation associated with a low rate of uncovered/malapposed struts and total absence of subclinical thrombi at 9 months follow up.

Longitudinal Neointimal Distribution Pattern After Everolimus-Eluting Stent Implantation: Insights From Optical Coherence Tomography Study

BACKGROUND/PURPOSE

Everolimus-eluting stents (EES) are established as latest generation drug eluting stents. However, optical coherence tomography (OCT) assessment of neointimal distribution after EES implantation is lacking. We aimed to assess the longitudinal neointimal distribution pattern after EES implantation using OCT.

METHODS

Data from 3 prospective studies (HEAL-EES, REVER and RESERVOIR), including patients with EES implantation and OCT follow-up study, were merged. Analyzed stents were divided into 3 segments of equal length (distal, medial, proximal). Longitudinal neointimal distribution patterns were compared between the 3 segments using generalized estimating equation. Neointimal thickness (NIT), neointimal area obstruction, and uncovered or malapposed struts were analyzed.

RESULTS

In total, 86 patients (92 lesions) were analyzed. Time of OCT follow-up was 9.0 ± 1.5 months. NIT was 101.7 ± 65.4 μm and neointimal obstruction area was 12.2 ± 7.6%. The number of assessed struts was the same in all three segments. NIT tended to be higher at the medial segment (108.8 ± 71.1 μm) compared to distal (103.0 ± 63.4 μm) and proximal (93.3 ± 61.1 μm) (p = 0.076). Neointimal area obstruction was significantly different between the 3 segments (12.4 ± 7.5% [distal], 13.1 ± 7.7% [medial], 11.1 ± 7.5% [proximal]; p = 0.037). In the proximal segment, there was a significantly higher frequency of uncovered struts compared to medial and distal segments (3.9% vs. 2.1% vs. 2.5%, p = 0.009). The distribution of malapposed struts was not significantly different.

CONCLUSIONS

Distribution of neointimal hyperplasia seems to be different between stent segments, being higher in the medial segment as compared to proximal and distal. Whether this may reflect a response to local pre-interventional plaque burden centrally covered by the stent should be confirmed in a future study.

MANUSCRIPT SUMMARY

As optical coherence tomography based assessment of neointimal distribution after everolimus-eluting stent implantation is lacking, we analyzed data of 86 patients (92 lesions) from 3 prospective trials to evaluate neointimal distribution in distal, medial and proximal stent segments. Neointimal hyperplasia seemed to be different between the three segments, with a higher burden in the medial stent segment. Whether this reflects a response to local pre-interventional plaque burden centrally covered by the stent should be confirmed in a future study.

Comparison of the vessel healing process after everolimus-eluting stent and bare metal stent implantations in patients with ST-elevation myocardial infarction

Cobalt-chromium everolimus-eluting stent (CoCr EES) is associated with a lower rate of stent thrombosis even in patients with ST-elevation myocardial infarction (STEMI). However, the time-serial changes of endothelial coverage of the stent struts in the extremely early period have never been reported, especially in patients with STEMI. The aim of this study was to compare the vessel healing process between CoCr EES and cobalt-chromium bare metal stent (CoCr BMS) implantations using optical coherence tomography (OCT) in patients with STEMI. Sixty-three patients who had primary emergent percutaneous coronary intervention (PCI) with CoCr EES (42 patients) or CoCr BMS (21 patients) were enrolled in this study for 3 years. OCT was performed just after, 2 and 12 weeks after EES or BMS implantations. Time-serial changes in the neointimal coverage (NIC), the neointimal thickness, and malapposition of stent struts were evaluated. NIC of stent struts did not differ between CoCr EES (23.2%, 99.4%) and CoCr BMS (24.0%, 97.8%) at 2 weeks and 12 weeks after PCI, respectively. Thicknesses of the neointima on the stent strut was significantly thinner in CoCr EES (34.0 ± 13.8, 107.0 ± 32.4 µm) than in CoCr BMS (40.0 ± 14.6, 115.7 ± 33.8 µm) at 2 weeks and 12 weeks after PCI (p = 0.011, p = 0.008), respectively. The malapposition did not differ just after PCI, and was completely resolved at 12 weeks after PCI in both groups. Thrombus was significantly less in CoCr EES than in CoCr BMS at 2 weeks (19.0% vs 42.9%, p < 0.01), and decreased over time in both groups, but at 12 weeks, disappeared only in CoCr EES (CoCr EES: 0% vs. CoCr BMS: 4.8%, p = 0.56). This study demonstrated that NIC and apposition of the stent struts almost completed at 12 weeks after EES and BMS implantations, while the neointimal thickness on the stent struts were thinner in EES than in BMS. Moreover, thrombus was significantly less in EES than in BMS implantations 2 weeks after PCI, which may explain the lower rate of acute and subacute stent thrombosis of EES compared with BMS.

An optical coherence tomography study of neointimal morphology and strut coverage at different time intervals from implantation of biodegradable polymer-coated sirolimus-eluting stents

OBJECTIVES

The aim of the study was to capture the evolution of neointima after implantation of a biodegradable polymer-coated, sirolimus-eluting, cobalt-chromium coronary stent system (BP-DES).

BACKGROUND

Optical coherence tomography (OCT) suggests that in-stent neointimal morphology influences clinical outcomes after DES implantation.

METHODS

Sixty patients treated with single BP-DES implantation were examined by quantitative coronary angiography (QCA) and OCT at 3, 6, and 12-month follow-up.

RESULTS

Median late lumen loss by QCA (mm) was 0.04 (IQR 0, 0.08), 0.17 (IQR 0, 0.32), and 0.14 (IQR 0.07, 0.31) at 3, 6, and 12-month follow-up respectively (P = 0.03). OCT cross-section multilevel analysis showed uncovered struts in 3.90%, 1.78%, and 0.02% of struts respectively (P = 0.03). The corresponding malapposition rates were 0.12%, 0.04%, and 0%. Lipid-rich neointima was observed only at 12-month follow-up in one restenotic lesion (0.77% cross-sections) that was accountable for the only target vessel revascularization. The homogeneous pattern was prevalent at all three time points, but its incidence displayed an upward trend (3 months: 59%; 6 months: 71%; 12 months: 88%) despite no difference in neointimal volume between 6 and 12 months. Conversely, a trend could be observed of decreasing incidence of heterogeneous pattern as the follow-up length increased.

CONCLUSIONS

In this study of a single-type BP-DES, the majority of stent struts were covered within 3 months from implantation. While the quantitative neointimal accumulation plateaued at 6 months with no further significant increase beyond 6 months, the neointima continued to evolve qualitatively and mature along with better strut coverage between 6 and 12 months after implantation.

Serial optical coherence tomography assessment of malapposed struts after everolimus-eluting stent implantation. A subanalysis from the HEAL-EES study

BACKGROUND

Incomplete stent apposition (ISA) is related to stent thrombosis, which is a serious adverse event. We aim to assess the time-course of ISA after 2nd generation everolimus-eluting stent (EES) implantation.

METHODS

In HEAL-EES study, we enrolled 36 patients who underwent percutaneous coronary intervention (PCI) with EES. OCT imaging was performed at baseline and follow-up. Patients were randomized 1:1:1 into 3 groups according to the time in which follow-up was performed: group A (6-month), group B (9-month), and group C (12-month). In this subanalysis, patients who had ISA segments at baseline and/or follow-up OCT were analyzed.

RESULT

At baseline, among 41 lesions in 36 patients, 20 lesions in 18 patients had ISA segments and were analyzed. At baseline, there were 3.0% ISA struts in group A (n=8), 2.8% in group B (n=4), and 4.5% in group C (n=8). At follow-up, ISA struts were present in 0.09%, 0.16% and 0.64%; respectively in groups A, B, and C. At follow-up, there was a significant decrease in the frequency of ISA: group A 3.0% vs. 0.09% (p<0.001), group B 2.8% vs. 0.16% (p<0.001), and group C 4.5% vs. 0.64% (p<0.001). In group A, there was one late acquired ISA at follow-up.

CONCLUSIONS

In patients undergoing 2nd generation EES implantation, area of acute ISA assessed by OCT, was almost resolved at 6-month follow-up.