Long-term safety of bioresorbable scaffolds: insights from a network meta-analysis including 91 trials

Long-term intracoronary imaging and physiological measurements of bioresorbable scaffolds and untreated atherosclerotic plaques

BACKGROUND

Bioresorbable scaffolds (BRS) provide the prospect of restoring the anatomic and physiologic characteristics of the vascular wall.

OBJECTIVE

This study sought to examine the long-term outcomes of BRS-based coronary intervention in a young population with diffuse and severe coronary atherosclerotic disease (CAD) and to compare the long-term evolution of treated segments versus the natural progression of untreated non-flow limiting stenoses.

METHODS

Observational, single-center cohort study that prospectively included patients that underwent percutaneous coronary intervention with implantation of ABSORB BRS (Abbott Vascular). The clinical endpoint was the incidence of device-oriented composite endpoint (DoCE) up to 5 years follow-up. A subgroup of patients with baseline intracoronary imaging assessment of long lesions and/or multivessel disease underwent elective angiographic (70 patients, 129 lesions) and intracoronary imaging (55 patients, 102 lesions) follow-up. Paired intravascular ultrasound (IVUS) and quantitative flow reserve (QFR) were analyzed.

RESULTS

Between 2012 and 2017, 159 patients (mean age 54.0 ± 11.1) with native CAD were treated with BRS on 247 lesions. Patients were mainly at their first cardiac event, mostly acute coronary syndromes (86.5%). At the median follow-up time of 56 months [41-65], DoCE occurred in 15/159 (9.4%) patients, while non-target vessel-oriented composite endpoint occurred in 16 patients (10.4%). A significant atherosclerotic progression was detected on residual non-flow limiting plaques as per IVUS and QFR assessment, while no significant change was detected in the treated segment.

CONCLUSIONS

Mild-to-moderate asymptomatic CAD progressed significantly at 5-year despite OMT. BRS-treated segments had a less aggressive progression at 5-year despite more severe and symptomatic CAD at baseline.

Coronary bioresorbable stents: Non-invasive quantitative evaluation of intra- and juxta-stent plaque composition-A computed tomography longitudinal study

PURPOSE

Coronary bioresorbable stents (BRS) do not produce blooming artifacts on computed tomography (CT), in contrast to metallic stents, as they are made of a bioresorbable polymer and are radiolucent. They allow to evaluate the coronary plaque beneath. The low-attenuation plaque (LAP) suggests plaque vulnerability and is CT assessable. The aim of our study was to show the possibility of a non-invasive CT evaluation of the volume and the LAP composition of the intra- and juxta-stent plaque.

METHODOLOGY

In our prospective longitudinal study, we recruited 27 consecutive patients (35 BRS stents total; mean age 60 +/- 9 years) with bioresorbable stents for a 256-slice ECG-synchronized CT evaluation at 1- and 12-months post stent implantation. Total plaque volume (mm3), absolute and relative (%) LAP volume per block in the pre- intra- and post-stent zones were analyzed; comparison 1- and 12-months post-implantation of BRS. Changes in the previously mentioned variables were assessed by the mixed effects models with and without spline, which also accounted for the correlation between repeated measurements.

RESULTS

Our block or spline model analysis has shown no significant difference in plaque or absolute LAP volumes in pre- intra- and post-stent zones between 1 and 12 months. Interestingly, % LAP volume increases near-significantly in the distal block of the intrastent at 12-mo follow-up (from 23.38 ± 1.80% to 26.90 ± 2.22% (increase of 15%), p = 0.052).

CONCLUSION

Our study demonstrates the feasibility of the repeated non-invasive quantitative analysis of the intrastent coronary plaque and of the in-stent lumen by CT scan.

Osstem Cardiotec Centum Stent Versus Xience Alpine Stent for De Novo Coronary Artery Lesion: A Multicenter, Randomized, Parallel-Designed, Single Blind Test

BACKGROUND AND OBJECTIVES

To compare the safety and efficacy of a new everolimus-eluting stent with an abluminal-coated biodegradable polymer (Osstem Cardiotec Centum) with those of the Xience Alpine stent (Xience).

METHODS

This randomized, prospective, multicenter, parallel-designed, single-blind trial was conducted among patients with myocardial ischemia undergoing percutaneous coronary intervention (PCI) from 21st September 2018 until 3rd July 2020. The primary efficacy endpoint was in-segment late lumen loss (LLL) at 270 days after the procedure and the primary safety endpoints were major adverse cardiac events (MACE), composite of cardiac death, myocardial infarction, and target lesion revascularization.

RESULTS

We enrolled 121 patients and analyzed 113 patients who finished 270 days of follow-up for the primary efficacy endpoint. The mean age of the participants was 66.8 years. As for the primary efficacy endpoint, LLL of the Osstem Cardiotec Centum group was 0.09±0.13 mm and that of the Xience group was 0.12±0.14 mm (upper limit of 1-sided 95% confidence interval, 0.02; p for non-inferiority, 0.0084). This result demonstrates the non-inferiority of the Osstem Cardiotec Centum. As for the primary safety endpoint, MACE occurred in one patient (1.59% of the Xience group). Meanwhile, no MACE occurred in the Osstem Cardiotec Centum group.

CONCLUSIONS

The Osstem Cardiotec Centum is non-inferior to the Xience Alpine® stent and is confirmed to be safe. It could be safely and effectively applied to patients with coronary artery disease undergoing PCI.

Very late vasomotor responses and gene expression with bioresorbable scaffolds and metallic drug-eluting stents

OBJECTIVES

To investigate the long-term vasomotor response and inflammatory changes in Absorb bioresorbable vascular scaffold (BVS) and metallic drug-eluting stent (DES) implanted artery.

BACKGROUND

Clinical evidence has demonstrated that compared to DES, BVS is associated with higher rates of target lesion failure. However, it is not known whether the higher event rates observed with BVS are related to endothelial dysfunction or inflammation associated with polymer degradation.

METHODS

Ten Absorb BVS and six Xience V DES were randomly implanted in the main coronaries of six nonatherosclerotic swine. At 4-years, vasomotor response was evaluated in vivo by quantitative coronary angiography response to intracoronary infusion of Ach and ex vivo by the biomechanical response to prostaglandin F2-α (PGF2-α), substance P and bradykinin and gene expression analysis.

RESULTS

Absorb BVS implanted arteries showed significantly restored vasoconstrictive responses after Ach compared to in-stent Xience V. The contractility of Absorb BVS treated segments induced by PGF2-α was significantly greater compared to Xience V treated segments and endothelial-dependent vasorelaxation was greater with Absorb BVS compared to Xience V. Gene expression analyses indicated the pro-inflammatory lymphotoxin-beta receptor (LTβR) signaling pathway was significantly upregulated in arteries treated with a metallic stent compared to Absorb BVS treated arterial segments.

CONCLUSIONS

At 4 years, arteries treated with Absorb BVS compared with Xience V, demonstrate significantly greater restoration of vasomotor responses. Genetic analysis suggests mechanobiologic reparation of Absorb BVS treated arteries at 4 years as opposed to Xience V treated vessels.

Three-year clinical outcome of biodegradable hybrid polymer Orsiro sirolimus-eluting stent and the durable biocompatible polymer Resolute Integrity zotarolimus-eluting stent: A randomized controlled trial

AIMS

We compared long-term clinical outcomes between patients treated with Orsiro sirolimus-eluting stent (O-SES) and those treated with durable biocompatible polymer Resolute Integrity zotarolimus-eluting stent (R-ZES).

METHODS AND RESULTS

The ORIENT trial was a randomized controlled noninferiority trial to compare angiographic outcomes between O-SES and R-ZES. We performed a post hoc analysis of 3-year clinical outcomes and included 372 patients who were prospectively enrolled and randomly assigned to O-SES (n = 250) and R-ZES (n = 122) groups in a 2:1 ratio. The primary endpoint was target lesion failure defined as a composite of cardiac death, nonfatal myocardial infarction, and target lesion revascularization. At 3 years, target lesion failure occurred in 4.7% and 7.8% of O-SES and R-ZES groups, respectively (hazard ratio, 0.58; 95% confidence intervals, 0.24-1.41; p = .232 by log-rank test). Secondary endpoints including cardiac death, myocardial infarction, and target lesion revascularization showed no significant differences between the groups. Stent thrombosis occurred in two patients in R-ZES group (0.0% vs. 1.6%, p = .040).

CONCLUSION

This study confirms long-term safety and efficacy of the two stents. We found a trend for lower target lesion failure with O-SES compared to R-ZES, although statistically insignificant.

Bioresorbable Vascular Scaffolds-Dead End or Still a Rough Diamond?

Percutaneous coronary interventions with stent-based restorations of vessel patency have become the gold standard in the treatment of acute coronary states. Bioresorbable vascular scaffolds (BVS) have been designed to combine the efficiency of drug-eluting stents (DES) at the time of implantation and the advantages of a lack of foreign body afterwards. Complete resolution of the scaffold was intended to enable the restoration of vasomotor function and reduce the risk of device thrombosis. While early reports demonstrated superiority of BVS over DES, larger-scale application and longer observation exposed major concerns about their use, including lower radial strength and higher risk of thrombosis resulting in higher rate of major adverse cardiac events. Further focus on procedural details and research on the second generation of BVS with novel properties did not allow to unequivocally challenge position of DES. Nevertheless, BVS still have a chance to present superiority in distinctive indications. This review presents an outlook on the available first and second generation BVS and a summary of results of clinical trials on their use. It discusses explanations for unfavorable outcomes, proposed enhancement techniques and a potential niche for the use of BVS.

Comparison of patency between two different peripheral self-expandable stents, absolute Pro® versus complete SE® in femoropopliteal occlusive disease

BACKGROUND

Self-expandable stents, Absolute Pro® (ABS) and Complete SE® (COM), demonstrated safety and efficacy in previous studies. We aimed to determine which stent is more effective for the endovascular treatment of femoropopliteal artery disease.

METHODS

We enrolled patients who underwent endovascular intervention from 2010 to 2015 in our hospital. The primary endpoint was clinical primary patency, which is a composite of freedom from restenosis or clinically driven target lesion revascularization (TLR).

RESULTS

A total of 197 patients and 210 limbs were analyzed, with 96 limbs of 88 patients assigned to the ABS group and 114 limbs of 109 patients assigned to the COM group. Baseline and lesion characteristics were similar between the two groups. The number of stents per limbs were 1.28±0.55 and 1.29±0.51 in the ABS and COM groups, respectively (P=0.92). The postprocedure ankle-brachial index was significantly improved in both groups compared with the preprocedural one (P<0.01), but there were no differences between the both groups at 6, 12, and 24 months after the index procedure. There were no significant differences in clinical primary patency rate (68.7% in ABS vs. 66.7% in COM, P=0.68) and TLR (9.4% in ABS vs. 14.0% in COM, P=0.41) between the two groups. There was no interaction of the clinical primary patency rate of the two stents and the patients' characteristics or lesion characteristics.

CONCLUSIONS

In this retrospective single-center study, ABS and COM showed no difference in clinical efficacy. Both stents can be effectively used for the endovascular intervention of femoropopliteal artery disease when it is necessary.

Undiscovered pathology of transient scaffolding t1remains a driver of failures in clinical trials

AIM

To statistically examine the released clinical trials and meta-analyses of polymeric bioresorbable scaffolds resuming the main accomplishments in the field with a translation to the routine clinical practice.

METHODS

The statistical power in clinical trials such as ABSORB Japan, ABSORB China, EVERBIO II, AIDA, and few meta-analyses by the post hoc odds ratio-based sample size calculation, and the patterns of artery remodeling published in papers from ABSORB A and B trials were evaluated.

RESULTS

The phenomenal admiration from the first ABSORB studies in 2006-2013 was replaced by the tremendous disappointment in 2014-2017 due to reported relatively higher rates of target lesion failure (a mean prevalence of 9.16%) and device thrombosis (2.38%) in randomized controlled trials. Otherwise, bioresorbable vascular scaffold (BVS) performs as well as the metallic drug-eluting stent (DES) with a trend toward some benefits for cardiac mortality [risk ratio (RR), 0.58-0.94, P > 0.05]. The underpowered design was confirmed for some studies such as ABSORB Japan, ABSORB China, EVERBIO II, AIDA trials, and meta-analyses of Polimeni, Collet, and Mahmoud with some unintentional bias (judged by the asymmetrical Funnel plot). Scaffold thrombosis rates with Absorb BRS were comparable with DES performed with a so-called strategy of the BVS implantation with optimized pre-dilation (P), sizing (S) and post-dilation (P) (PSP) implantation (RR, PSP vs no PSP 0.37) achieving 0.35 per 100 patient-years, which is comparable to the RR 0.49 with bare-metal stents and the RR 1.06 with everolimus DES. Both ABSORB II and ABSORB III trials were powered enough for a five-year follow-up, but the results were not entirely conclusive due to the mostly non-significant fashion of data. The powered meta-analyses were built mostly on statistically poor findings.

CONCLUSION

The misunderstanding of the pathology of transient scaffolding drives the failures of the clinical trials. More bench studies of the vascular response are required. Several next-generation BVS including multifunctional electronic scaffold grant cardiology with a huge promise to make BVS technology great again.

Mid-term outcomes of the Absorb BVS versus second-generation DES: A systematic review and meta-analysis

Background

Bioresorbable Vascular Scaffolds (BVS) were introduced to overcome some of the limitations of drug-eluting stent (DES) for PCI. Data regarding the clinical outcomes of the BVS versus DES beyond 2 years are emerging.

Objective

To study mid-term outcomes.

Methods

We searched online databases (PubMed/Medline, Embase, CENTRAL), several websites, meeting presentations and scientific session abstracts until August 8^th, 2017 for studies comparing Absorb BVS with second-generation DES. The primary outcome was target lesion failure (TLF). Secondary outcomes were all-cause mortality, myocardial infarction, target lesion revascularization (TLR) and definite/probable device thrombosis. Odds ratios (ORs) with 95% confidence intervals (CIs) were derived using a random effects model.

Results

Ten studies, seven randomized controlled trials and three propensity-matched observational studies, with a total of 7320 patients (BVS n = 4007; DES n = 3313) and a median follow-up duration of 30.5 months, were included. Risk of TLF was increased for BVS-treated patients (OR 1.34 [95% CI: 1.12–1.60], p = 0.001, I² = 0%). This was also the case for all myocardial infarction (1.58 [95% CI: 1.27–1.96], p<0.001, I² = 0%), TLR (1.48 [95% CI: 1.19–1.85], p<0.001, I² = 0%) and definite/probable device thrombosis (of 2.82 (95% CI: 1.86–3.89], p<0.001 and I² = 40.3%). This did not result in a difference in all-cause mortality (0.78 [95% CI: 0.58–1.04], p = 0.09, I² = 0%). OR for very late (>1 year) device thrombosis was 6.10 [95% CI: 1.40–26.65], p = 0.02).

Conclusion

At mid-term follow-up, BVS was associated with an increased risk of TLF, MI, TLR and definite/probable device thrombosis, but this did not result in an increased risk of all-cause mortality.

Coronary Bioresorbable Scaffolds in Interventional Cardiology: Lessons Learnt and Future Perspectives

Polymer- and magnesium-based bioresorbable scaffolds were developed with the intention of restoring a functionally intact arterial wall following the scaffold’s biodegradation, avoiding the limitations of coronary stenting associated with persistent vasomotor dysfunction and sustained inflammation leading to in-stent neo-atherosclerosis. Although initial experimental observations encouraged the development of first-in-man registries and the execution of larger randomized trials, clinical results from treating relatively non-complex lesions with these technologies failed to demonstrate any incremental benefit. Furthermore, the significantly higher rates of scaffold thrombosis with the current generation scaffolds led to existing polymer-based technologies being withdrawn from the US clinical market. This article provides an overview of the preclinical and clinical lessons learnt from the recently conducted ABSORB trials using the first-generation Absorb bioresorbable vascular scaffold (Abbott Vascular), which is the most investigated coronary scaffold in clinical trials, and reflects on whether these technologies are a viable alternative to contemporary metal stents for coronary revascularization.