Acute Mechanical Performance of Magmaris vs. DESolve Bioresorbable Scaffolds in a Real-World Scenario

Magnesium-based bioresorbable flow diverter for intracranial aneurysms: a pilot study of biocompatibility and bioresorption in a rabbit vascular model

BACKGROUND

Bioresorbable flow diverters (BRFDs) have the potential to solve several problems associated with conventional permanent flow diverters. We have constructed bare and poly-L-lactic acid (PLLA)-coated magnesium BRFDs (MgBRFDs) using a high-strength corrosion-resistant magnesium alloy. This study aimed to compare bioresorption and biocompatibility between the two types in a rabbit vascular model to determine which is more clinically feasible in humans.

METHODS

Bare and PLLA-coated MgBRFDs were fabricated by braiding 48 thin magnesium alloy wires. Mechanical testing was conducted. Bare (n=13) and PLLA-coated (n=13) MgBRFDs were implanted into rabbit aortas and harvested 14, 30, and 90 days after implantation. The physical structure of the resolution process was examined using optical coherence tomography (OCT), micro-computed tomography, and scanning electron microscopy (SEM). The biological response of the vascular tissue was examined using SEM and histopathological analysis.

RESULTS

The porosity and pore density of the bare MgBRFD were 64% and 16 pores/mm2, respectively; corresponding values for the PLLA-coated MgBRFD were 63% and 12 pores/mm2, respectively. The OCT attenuation score was significantly higher for the PLLA-coated MgBRFD at all time points (14 days, P=0.01; 30 days, P=0.02; 90 days, P=0.004). OCT, micro-computed tomography, and SEM demonstrated better stent structure preservation with the PLLA-coated MgBRFD. Neointimal thickness did not significantly change over time in either type of MgBRFD (bare, P=0.93; PLLA-coated, P=0.34); however, the number of inflammatory and proliferative cells peaked at 14 days and then decreased.

CONCLUSIONS

Both bare and PLLA-coated MgBRFDs had excellent biocompatibility. The PLLA-coated MgBRFD has greater clinical feasibility because of its delayed bioresorption.

Long-term outcomes following bioresorbable vascular scaffolds

INTRODUCTION

The higher scaffold thrombosis rates observed with the first-generation bioresorbable scaffolds (BRSs) compared to conventional drug-eluting stents were likely due in part to bioresorbable polymers having insufficient radial strength, necessitating larger strut profiles. Meta-analysis of the long-term outcomes from the first-generation Absorb bioresorbable vascular scaffold (BVS) showed that this period of excess risk ended at 3 years. Therefore, current attention has been focused on improving early outcomes by increasing the scaffold's tensile strength and reducing strut thickness.

AREAS COVERED

This review summaries the lessons learned from the first-generation BRS. It updates the long-term clinical outcomes of trials evaluating the ABSORB BVS and metallic alloy-based BRS. In addition, it reviews the next-generation BRSs manufactured in Asia.

EXPERT OPINION

Critical areas to improve the performance and safety of biodegradable scaffolds include further development in material science, surface modification, delivery systems, and long-term follow-up studies.

One- and two-year clinical outcomes of treatment with resorbable magnesium scaffolds for coronary artery disease: the prospective, international, multicentre BIOSOLVE-IV registry

BACKGROUND

Bioresorbable scaffolds have been developed to overcome the limitations of drug-eluting stents and to reduce long-term adverse events.

AIMS

We aimed to assess the long-term safety and efficacy of a sirolimus-eluting resorbable magnesium scaffold to ensure its safe rollout into clinical routine.

METHODS

BIOSOLVE-IV is a prospective, international, multicentre registry including more than 100 centres in Europe, Asia, and Asia-Pacific. Enrolment started directly after the commercialisation of the device. Follow-up assessments are scheduled at 6 and 12 months, and annually for up to 5 years; we herein report the 24-month outcomes.

RESULTS

Overall, 2,066 patients with 2,154 lesions were enrolled. Patients were 61.9±10.5 years old, 21.6% had diabetes, and 18.5% had non-ST-elevation myocardial infarction (NSTEMI). Lesions were 14.8±4.0 mm long with a reference vessel diameter of 3.2±0.3 mm. Device and procedure success were 97.5%, and 99.1%, respectively. The 24-month target lesion failure (TLF) rate was 6.8%, mainly consisting of clinically driven target lesion revascularisations (6.0%). Patients with NSTEMI had significantly higher TLF rates than those without (9.3% vs 6.2%; p=0.025), whereas there were no significant differences observed for patients with diabetes or with type B2/C lesions (a 24-month TLF rate of 7.0% and 7.9%, respectively). The 24-month rate of definite or probable scaffold thrombosis was 0.8%. Half of the scaffold thromboses occurred after premature discontinuation of antiplatelet/anticoagulation therapy, and only one scaffold thrombosis occurred beyond the 6-month follow-up, on day 391.

CONCLUSIONS

The BIOSOLVE-IV registry showed good safety and efficacy outcomes, confirming a safe rollout of the Magmaris into clinical practice.

Long-Term Performance of the Magmaris Drug-Eluting Bioresorbable Metallic Scaffold in All-Comers Patients’ Population

Background: The long-term efficacy and safety of bioresorbable vascular scaffolds (BVS) in real world clinical practice including Magmaris need to be elucidated to better understand performance of this new and evolutive technology. The aim of this study was to evaluate long-term performance of Magmaris, drug-eluting bioresorbable metallic scaffold, in all-comers patients’ population. Methods: We included in this prospective registry first 54 patients (54 ± 11 years; male 46) treated with Magmaris, with at least 30 months of follow-up. Diabetes mellitus and acute coronary syndrome were present in 33 (61%) and 30 (56%) of the patients, respectively. Patients were followed for device- and patient-oriented cardiac events during a median follow-up of 47 months (DOCE–cardiac death, target vessel myocardial infarction, and target lesion revascularization; POCE–all cause death, any myocardial infarction, any revascularization). Results: Event-free survivals for DOCE and POCE were 86.8% and 79.2%, respectively. The rate of DOCE was 7/54 (13%), including in total target vessel myocardial infarction in two patients (4%), target lesion revascularization in six patients (11%), and no cardiac deaths. The rate of POCE was 11/54 (21%), including in total any myocardial infarctions in 3 patients (6%), any revascularization in 11 patients (20%), and no deaths. Definite Magmaris thrombosis occurred in two patients (3.7%), and in-scaffold restenosis developed in five patients (9.3%). Variables associated with DOCE were implantation of ≥2 Magmaris BVS (HR: 5.4; 95%CI: 1.21–24.456; p = 0.027) and total length of Magmaris BVS ≥ 40 mm (HR: 6.4; 95%CI: 1.419–28.855; p = 0.016), whereas previous PCI was the only independent predictor of POCE (HR: 7.4; 95%CI: 2.216–24.613; p = 0.001). Conclusions: The results of the long-term clinical outcome following Magmaris implantation in patients with complex clinical and angiographic features were acceptable and promising. Patients with multi-BVS and longer multi-BVS in lesion implantation were associated with worse clinical outcome.