Randomised comparison of vascular response to biodegradable polymer sirolimus eluting and permanent polymer everolimus eluting stents: An optical coherence tomography study

Can an ultrathin strut stent design and a polymer free, proendothelializing probucol matrix coating improve early strut healing? The FRIENDLY-OCT trial. An intra-patient randomized study with OCT, evaluating early strut coverage of a novel probucol coated polymer-free and ultra-thin strut sirolimus-eluting stent compared to a biodegradable polymer sirolimus-eluting stent

BACKGROUND

incomplete strut coverage determines the risk of stent thrombosis in the first months after stent implantation.

AIMS

To evaluate the potential better early healing of a novel probucol coated polymer free ultra-thin strut sirolimus eluting stent (PF-SES). [Clinical trial unique identifier: NCT02785237].

METHODS

Patients with two (angiographically similar) lesions with clinical indication for PCI were enrolled. The investigated stent was compared to a thin strut, bioresorbable polymer, sirolimus eluting stent (BP-SES). Every patient received both stents, one in each lesion, assigned in a randomized sequence. OCT was systematically performed at 3 months. Primary end point was the difference in the proportion of covered struts at 3 months (defined as ≥20 μm of tissue coverage). Secondary end points included differences in percentage of uncovered struts (0 μm coverage), mean strut coverage thickness, and malapposed struts' coverage proportion. Major adverse cardiac events (cardiac death, myocardial infarction, target lesion revascularization, and definite or probable stent thrombosis) at 12 months were also evaluated.

RESULTS

70 patients were included. At 3 months, a consistent and significantly higher strut coverage rate (≥20 μm) was observed in PF-SES as compared to BP-SES, both for well apposed (87.3% versus 79.1%, p < 0.001) and malapposed struts (50.4% vs 37.8%, p 0.00). Uncoverage rate (0 μm) was also significantly lower for the PF-SES (3.1% vs 5.3%, p < 0.001). There were no differences in clinical endpoints.

CONCLUSION

The probucol coated non-polymeric ultra-thin strut sirolimus eluting stent showed a significantly better early strut coverage at 3 months.

Optical coherence tomography tissue coverage and characterization at six months after implantation of bioresorbable scaffolds versus conventional everolimus eluting stents in the ISAR-Absorb MI trial

Purpose

Data regarding vessel healing by optical coherence tomography (OCT) after everolimus-eluting bioresorbable scaffolds (BRS) or everolimus-eluting metallic stent (EES) implantation in acute myocardial infarction (AMI) patients is scarce. We compared OCT findings after BRS or EES implantation in patients with AMI enrolled in a randomized trial.

Methods

In ISAR-Absorb MI, AMI patients were randomized to BRS or EES implantation, with 6–8 month angiographic follow-up. This analysis includes patients who underwent OCT during surveillance angiography. Tissue characterization was done using grey-scale signal intensity analysis. The association between OCT findings and target lesion failure (TLF) at 2 years was investigated.

Results

OCT was analyzed in 103 patients (2237 frames, 19,827 struts) at a median of 216 days post-implantation. Of these, 70 were treated with BRS versus 32 with EES. Pre-(92.8 vs. 68.7%, p = 0.002) and post-dilation (51.4 vs. 12.5%, p < 0.001) were more common in BRS as compared to EES. Strut coverage was higher in BRS vs. EES (97.5% vs. 90.9%, p < 0.001). Mean neointimal thickness was comparable in both groups [85.5 (61.9, 124.1) vs. 69.5 (32.7, 127.5) µm, respectively, p = 0.20]. Mature neointimal regions were numerically more common in BRS (43.0% vs. 24.6%; p = 0.35); this difference was statistically significant in ST-elevation myocardial infarction patients (40.9% vs. 21.1%, p = 0.03).

At two-years, 8 (7.8%) patients experienced TLF. Mean neointimal area [0.61 (0.21, 1.33) vs. 0.41 (0.11, 0.75) mm², p = 0.03] and mean neointimal coverage [106.1 (65.2, 214.8) vs. 80.5 (53.5, 122.1) µm, p < 0.01] were higher, with comparable tissue maturity, in lesions with versus without TLF.

Conclusions

In selected patients who underwent OCT surveillance 6–8 months after coronary intervention for AMI with differing implantation characteristics depending on the device type used, vessel healing was more advanced in BRS compared with EES, particularly in the STEMI subgroup.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10554-021-02251-x.

Comparison of neointimal coverage between ultrathin biodegradable polymer-coated sirolimus-eluting stents and durable polymer-coated everolimus-eluting stents: 6 months optical coherence tomography follow-up from the TAXCO study

Aim

The TAXCO study was designed to compare the degree of neointimal coverage and the prevalence of malapposition at 6 months subsequent to implantation of ultrathin biodegradable polymer‐coated sirolimus‐eluting stents (SES) and durable polymer‐coated everolimus‐eluting stents (EES) of thin strut thickness using optical coherence tomography (OCT).

Methods

The TAXCO study included a total of 42 patients who gave consent and underwent OCT examination between August 2017 and September 2017. Of 42, five patients' OCT examinations were of insufficient quality for quantitative analysis. Thus, the OCT analysis group consisted of 37 patients. Among them, 16 patients were treated with Xience (Abbott Vascular) and 21 with Tetriflex (Sahajanand Medical Technologies Pvt. Ltd., Surat, India), 6 (±1) months earlier at our institution. The OCT was performed using a C7 Dragonfly™ imaging catheter (St. Jude Medical Inc.). All OCT images were analyzed at an independent core laboratory (Cardiovascular Research Center, São Paulo, Brazil) by analysts who were blinded to patient and procedural information.

Results

A total of 763 crosssections (6,882 struts) were analyzed in Xience group, and 1,127 crosssections (9,968 struts) in Tetriflex group. At 6 months, on per‐lesion basis, no significant differences were observed between Xience group and Tetriflex group in mean percentage of uncovered struts (1.87 ± 3.86 vs. 2.42 ± 3.46, p = .137) and malapposed struts (0.05 ± 0.2 vs. 0.21 ± 0.69, p = .302). Strut‐level neointimal thickness also did not differ between Xience group and Tetriflex group (0.18 ± 0.12 vs. 0.14 ± 0.08 mm, p = .286).

Conclusion

This OCT study found no significant difference in strut coverage and neointimal thickness at 6 months after implantation of biodegradable polymer‐coated Tetriflex, when compared with durable polymer‐coated Xience.

Endpoint selection for noninferiority percutaneous coronary intervention trials: a methodological description

Background:

The objective of this review is to provide a practical update on endpoint selection for noninferiority (NI) studies in percutaneous coronary intervention studies.

Methods:

A PubMed search was conducted for predefined terms to explore the use of NI designs and intrapatient comparisons to determine their current importance. Sample size calculations for the most frequently used endpoints with NI hypotheses were done to increase statistical awareness.

Results:

Reported NI trials, with the most frequently chosen clinical endpoint of major adverse cardiac events (MACE), had NI margins ranging from 1.66% to 5.00%, resulting in patient populations of 400–1500 per treatment group. Clinical study endpoints comprising of MACE complemented with rates of bleeding complications and stent thrombosis (ST) are suggested to conduct a statistically and clinically meaningful NI trial. Study designs with surrogate endpoints amenable to intrapatient randomizations, are a very attractive option to reduce the number of necessary patients by about half. Comparative clinical endpoint studies with MACE and ST/bleeding rates to study a shortened dual antiplatelet therapy (DAPT) in coronary stent trials are feasible, whereas ST as the sole primary endpoint is not useful.

Conclusions:

Expanded composite clinical endpoints (MACE complemented by ST and bleeding rates and intrapatient randomization for selected surrogate endpoints) may be suitable tools to meet future needs in device approval, recertification and reimbursement.

Outcomes of patients treated with ultrathin-strut biodegradable polymer sirolimus-eluting stents versus fluoropolymer-based everolimus-eluting stents: a meta-analysis of randomised trials

AIMS

The ultrathin-strut biodegradable polymer sirolimus-eluting stent (SES) is a new-generation drug-eluting stent (DES) developed to improve the percutaneous treatment of patients with coronary artery disease. Here, we sought to investigate whether the performance of the ultrathin-strut biodegradable polymer SES is superior to that of the benchmark thin-strut fluoropolymer-based everolimus-eluting stent (EES).

METHODS AND RESULTS

We undertook a study-level meta-analysis of trials in which patients receiving percutaneous coronary intervention (PCI) were randomly assigned to either SES or EES. Primary efficacy and safety outcomes were target lesion revascularisation (TLR) and definite/probable stent thrombosis (ST), respectively. Secondary outcomes were myocardial infarction (MI), death, target lesion failure (TLF) and target vessel failure (TVF). A total of 4,853 patients received a PCI with either SES (n=2,816) or EES (n=2,037) in six trials. After a weighted median follow-up of 12 months, patients treated with SES had a risk of TLR (odds ratio [95% confidence interval]: 1.24 [0.83-1.85], p=0.30), definite/probable ST (0.84 [0.53-1.33], p=0.45) and MI related to the target vessel (0.77 [0.55-1.07], p=0.12) comparable to that of patients treated with EES. We found no significant difference with regard to other secondary outcomes.

CONCLUSIONS

At one-year follow-up, the ultrathin-strut biodegradable polymer sirolimus-eluting stent displays a performance comparable to that of the fluoropolymer-based everolimus-eluting stent.

Optical Coherence Tomography Tissue Coverage and Characterization with Grey-Scale Signal Intensity Analysis After Bifurcation Stenting with a New Generation Bioabsorbable Polymer Drug-Eluting Stent

PURPOSE

Bifurcation stenting is thought to be associated with delayed healing and a subsequent risk of stent failure. The aim of this study was to further evaluate healing of thin-strut bioabsorbable polymer everolimus-eluting stents (EES) post bifurcation stenting by optical coherence tomography (OCT) including grey-scale signal intensity (GSI) analysis.

METHODS

Patients undergoing bifurcation stenting with a planned two-stent approach using EES with OCT follow-up at 3-6 months post-stenting were included in this study. Morphometric analysis of contiguous cross-sections was performed at 1 mm longitudinal intervals within the stented segment. GSI analysis of neointimal regions of interest (ROI) overlying stent struts was performed for each of these cross-sections. Tissue coverage was classified as mature or immature.

RESULTS

Data on a total of 31 lesions (17 cases) was available at a median of 168 days post stenting. Mean length of stented segments was 27.7 ± 16.6 mm. The mean minimum stent area was 6.50 ± 2.71 mm² while the mean stent area was 8.69 ± 3.08 mm². Amongst a total of 847 assessed frames, 9716 struts were visible. Overall strut coverage was 95.9%; 0.3% of struts were malapposed. The mean thickness of neointimal coverage was 100.95 ± 42.03 μm and the mean percentage area stenosis was 9.03 ± 7.80%. A total of 53.79% of ROIs were classified as mature.

CONCLUSIONS

After implantation of EES in bifurcation lesions, rates of uncovered and malapposed struts were low. GSI analysis showed that more than half of neointimal areas analyzed were classified as mature in keeping with advanced vessel healing.

Qualitative and quantitative neointimal characterization by optical coherence tomography in patients presenting with in-stent restenosis

AIMS

To describe optical coherence tomography (OCT) findings in patients with in-stent restenosis (ISR) and determine predictors of neointimal patterns and neoatherosclerosis.

METHODS AND RESULTS

Patients undergoing OCT prior to PCI for ISR in three European centres were included. Analyses were performed in a core laboratory. Qualitative and quantitative [gray-scale signal intensity (GSI)] neointima analyses were performed on a per quadrant basis. A total of 107 patients were included. Predominantly homogeneous lesions included 4.5% (0.0-14.3) non-homogeneous quadrants, while predominantly non-homogeneous ones included 28.1% (20.3-37.5) homogeneous quadrants. Mean GSI values differed significantly between homogeneous [108.4 (92.5-123.6)], non-homogeneous [79.9 (61.2-95.9)], and neoatherosclerosis [88.3 (72.8-104.9)] quadrants (p < 0.001 for all comparisons). Stent underexpansion was observed in 48.5% and 61.1% of lesions, respectively (p = 0.225). Female sex and maximal neointimal thickness independently correlate with a non-homogeneous pattern, while angiographic pattern and diabetes mellitus inversely correlate with such pattern. Time from index stenting procedure was the only independent predictor of neoatherosclerosis.

CONCLUSIONS

Different neointimal patterns coexist in a significant proportion of ISR lesions. GSI values differ significantly between neointimal categories. Neoatherosclerosis is a time-dependent phenomenon, displaying different time courses in DES compared to BMS, with earlier appearance in the former group. Stent underexpansion is a frequent finding in patients with ISR.