Current status of clinically available bioresorbable scaffolds in percutaneous coronary interventions

Magnesium ion leachables induce a conversion of contractile vascular smooth muscle cells to an inflammatory phenotype

Phenotype switching is a characteristic response of vascular smooth muscle cells (vSMCs) to the dynamic microenvironment and contributes to all stages of atherosclerotic plaque. Here, we immersed pure magnesium and AZ31 alloy in the completed medium under cell culture condition, applied the resultant leaching extracts to the isolated contractile rat aortic vSMCs and investigated how vSMCs phenotypically responded to the degradation of the magnesium-based stent materials. vSMCs became more proliferative and migratory but underwent more apoptosis when exposed to the degradation products of pure magnesium; while the AZ31 extracts caused less cell division but more apoptosis, thus slowing cell moving and growing. Noticeably, both leaching extracts dramatically downregulated the contractile phenotypic genes at mRNA and protein levels while significantly induced the inflammatory adhesive molecules and cytokines. Exogenously added Mg ions excited similar transformations of vSMCs. With the liberation or supplementation of Mg²⁺ , the expression patterns of the pro-contractile transactivator myocardin and the pro-inflammatory transcriptional factor kruppel-like factor 4 (KLF4) were reversed. Overall, the degradation of the Mg-based materials would evoke a shift of the contractile vSMCs to an inflammatory phenotype via releasing Mg ions to induce a transition from the phenotypic control of vSMCs by the myocardin to that by the KLF4. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 988-1001, 2019.

Thirty-Day and One-Year Clinical Outcomes of Bioresorbable Vascular Scaffold Implantation: A Single-Center Experience

Background

Available data on the use of the Bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, CA) in real-world patients is limited, particularly in Asian populations. The aim of this study was to assess clinical outcomes of patients treated with a BVS in real-world practice in Taiwan.

Methods

This study focused on 156 patients with coronary artery disease and a total of 249 lesions who received BVS implantation from October 2012 to October 2015. The study's primary endpoint was major adverse cardiac event (MACE), such as a myocardial infarction (MI), target vessel revascularization (TVR), target lesion revascularization (TLR), definite or possible scaffold thrombosis, cardiovascular death, and all-cause mortality during the thirty-day follow-up period. The secondary endpoint was MACE during the one-year follow-up period. Additionally, the composite clinical secondary endpoint was target lesion failure (TLF), which was called device-oriented composite endpoint.

Results

The average age of the patients was 60.34 ± 10.15 years, and 81.4% were male. The average of Syntax score was 12.42 ± 8.77 points. 44.2 % lesions were type B2 or C. At 31 days, one patient experienced a MACE (1/156) the composite of two TLF (2/249) with ST elevation MI, which was related to scaffold thrombosis. At one-year, 5.1 % (8/156) of the patients experienced a MACE and 3.6% (9/249) of the lesions experienced a TLF. There was no cardiovascular or all-cause mortality in the 30-day follow-up. The one-year cardiovascular and all-cause mortality rates were each 1.3%, respectively. Diabetes, ostial lesion, bifurcation lesion, and non-standard dual anti-platelet therapy (DAPT) were the strong associations of one-year TLF.

Conclusions

Even with difficult and complex lesions of patients in this study, acceptable outcomes were achieved with low definite or possible scaffold thrombosis rates after BVS implantation. And despite anatomical issues, it is important to complete standard DAPT.

Reduced number of cardiovascular events and increased cost-effectiveness by genotype-guided antiplatelet therapy in patients undergoing percutaneous coronary interventions in the Netherlands

Aim

This study explores clinical outcome in cytochrome P450 2C19 (CYP2C19)-related poor metaboliser patients treated with either clopidogrel or prasugrel after percutaneous coronary intervention (PCI) and investigates whether this could be cost-effective.

Methods and results

This single-centre, observational study included 3260 patients scheduled for elective PCI between October 2010 and June 2013 and followed for adverse cardiovascular events until October 2014. Post PCI, CYP2C19 poor metaboliser patients were treated with clopidogrel or prasugrel, in addition to aspirin. In total, 32 poor metabolisers were treated with clopidogrel and 41 with prasugrel. The number of adverse cardiovascular events, defined as death from cardiovascular cause, myocardial infarction, stent thrombosis, every second visit to the catheterisation room for re-PCI in the same artery, or stroke, within 1.5 years of PCI, was significantly higher in the CYP2C19 poor metaboliser group treated with clopidogrel (n = 10, 31 %) compared with the poor metaboliser group treated with prasugrel (n = 2, 5 %) (p = 0.003). Costs per gained quality-adjusted life years (QALY) were estimated, showing that genotype-guided post-PCI treatment with prasugrel could be cost-effective with less than € 10,000 per gained QALY.

Conclusion

This study provides evidence that for CYP2C19-related poor metabolisers prasugrel may be more effective than clopidogrel to prevent major adverse cardiovascular events after PCI and this approach could be cost-effective.

Treatment variation in stent choice in patients with stable or unstable coronary artery disease

AIM

Variations in treatment are the result of differences in demographic and clinical factors (e.g. anatomy), but physician and hospital factors may also contribute to treatment variation. The choice of treatment is considered important since it could lead to differences in long-term outcomes. This study explores the associations with stent choice: i.e. drug-eluting stent (DES) versus bare-metal stents (BMS) for Dutch patients diagnosed with stable or unstable coronary artery disease (CAD).

METHODS & RESULTS

Associations with treatment decisions were based on a prospective cohort of 692 patients with stable or unstable CAD. Of those patients, 442 patients were treated with BMS or DES. Multiple logistic regression analyses were performed to identify variables associated with stent choice. Bivariate analyses showed that NYHA class, number of diseased vessels, previous percutaneous coronary intervention, smoking, diabetes, and the treating hospital were associated with stent type. After correcting for other associations the treating hospital remained significantly associated with stent type in the stable CAD population.

CONCLUSIONS

This study showed that several factors were associated with stent choice. While patients generally appear to receive the most optimal stent given their clinical characteristics, stent choice seems partially determined by the treating hospital, which may lead to differences in long-term outcomes.

Appropriate use of bioresorbable vascular scaffolds in percutaneous coronary interventions: a recommendation from experienced users : A position statement on the use of bioresorbable vascular scaffolds in the Netherlands

Percutaneous coronary interventions (PCI) have become a reliable revascularisation option to treat ischaemic coronary artery disease. Drug-eluting stents (DES) are widely used as first choice devices in many procedures due to their established good medium to long term outcomes. These permanent implants, however, do not have any residual function after vascular healing following the PCI. Beyond this initial healing period, metallic stents may induce new problems, resulting in an average rate of 2 % reinterventions per year. To eliminate this potential late limitation of permanent metallic DES, bioresorbable coronary stents or ‘vascular scaffolds’ (BVS) have been developed. In a parallel publication in this journal, an overview of the current clinical performance of these scaffolds is presented. As these scaffolds are currently CE marked and commercially available in many countries and as clinical evidence is still limited, recommendations for their general usage are needed to allow successful clinical introduction.