Serial invasive imaging follow-up of the first clinical experience with the Magmaris magnesium bioresorbable scaffold

Long-Term Outcomes After Implantation of Magnesium-Based Bioresorbable Scaffolds—Insights From an All-Comer Registry

Background

The magnesium-based sirolimus-eluting bioresorbable scaffold (Mg-BRS) Magmaris™ showed promising clinical outcomes, including low rates of both the target lesion failure (TLF) and scaffold thrombosis (ScT), in selected study patients. However, insights regarding long-term outcomes (>2 years) in all-comer populations remain scarce.

Methods

We analyzed data from a single-center registry, including patients with acute coronary syndrome (ACS) and chronic coronary syndrome (CCS), who had undergone percutaneous coronary intervention (PCI) using the Mg-BRS. The primary outcome comprised the device-oriented composite endpoint (DoCE) representing a hierarchical composite of cardiac death, ScT, target vessel myocardial infarction (TV-MI), and clinically driven target lesion revascularization (TLR) up to 5 years.

Results

In total, 84 patients [mean age 62 ± 11 years and 63 (75%) men] were treated with the Mg-BRS devices between June 2016 and March 2017. Overall, 101 lesions had successfully been treated with the Mg-BRS devices using 1.2 ± 0.4 devices per lesion. Pre- and postdilatation using dedicated devices had been performed in 101 (100%) and 98 (97%) of all the cases, respectively. After a median follow-up time of 62 (61–64) months, 14 (18%) patients had experienced DoCEs, whereas ScT was encountered in 4 (4.9%) patients [early ScTs (<30 days) in three cases and two fatal cases]. In 4 (29%) of DoCE cases, optical coherence tomography confirmed the Mg-BRS collapse and uncontrolled dismantling.

Conclusion

In contradiction to earlier studies, we encountered a relatively high rate of DoCEs in an all-comer cohort treated with the Mg-BRS. We even observed scaffold collapse and uncontrolled dismantling. This implicates that this metal-based BRS requires further investigation and may only be used in highly selected cases.

Optical coherence tomography versus angiography guided magnesium bioresorbable scaffold implantation in NSTEMI patients

BACKGROUND

The purpose of a bioresorbable scaffold (BRS) is to provide radial support during coronary healing. In this study, coronary artery healing after optical coherence tomography (OCT)- versus angiography-guided magnesium BRS (MBRS) implantation in patients with non-ST-segment-elevation myocardial infarction (NSTEMI) is compared.

METHODS

75 patients were randomized 1:1 to OCT- or angiography-guided implantation of a MBRS with protocolled pre- and post-dilation. In the OCT-guided group, prespecified criteria indicating additional intervention were (1) scaffold under-expansion, (2) strut malapposition, (3) edge dissection, and (4) residual stenosis at distal or proximal reference segments. The primary endpoint was OCT-derived healing stage at 6 months.

RESULTS

At 6 months, there was no difference in average healing stage between OCT- and angiography-guided intervention (4.6 [interquartile range (IQR): 4.5-4.7] versus 4.5 [IQR: 4.3-4.7]; p = 0.54). The MBRSs were completely resolved in 77.0% [IQR: 68.5-85.5] versus 76.5% [IQR: 67.9-85.5]; (p = 0.97). Minimal lumen area (MLA) was reduced at 6 months in both the OCT- (32.3%; p < 0.01) and the angiography-guided group (21.3%; p < 0.01), however OCT-guided implantation was associated with a greater reduction of total lumen volume (-27.1 ± 32.5 mm³ versus -5.0 ± 32.9 mm³; p < 0.01) and MLA (-2.3 ± 1.6 mm² vs. -1.4 ± 1.4 mm²; p = 0.02).

CONCLUSIONS

In NSTEMI patients, OCT-guidance with protocolled pre- and post-dilation of MBRS implantation showed similar healing pattern at 6 months compared to angiography-guidance alone.

CLINICAL TRIAL REGISTRATION

The Coronary Artery Healing Process after Optical Coherence Tomography Guided Percutaneous Coronary Intervention with Magmaris Bioresorbable Scaffold in Patients with Non-ST-Segment-Elevation Myocardial Infarction: (HONEST) trial is registered with ClinicalTrials.gov, NCT03016624.

BIOSOLVE-IV-registry: Safety and performance of the Magmaris scaffold: 12-month outcomes of the first cohort of 1,075 patients

OBJECTIVES

We aimed to assess the safety and performance of the Magmaris sirolimus-eluting bioresorbable magnesium scaffold in a large patient population.

BACKGROUND

Magmaris has shown good outcomes in small-sized controlled trials, but further data are needed to confirm its usability, safety, and performance.

METHODS

BIOSOLVE-IV is an international, single arm, multicenter registry including patients with a maximum of two single de novo lesions. Follow-up is scheduled up to 5 years; the primary outcome is target lesion failure (TLF) at 12 months.

RESULTS

A total of 1,075 patients with 1,121 lesions were enrolled. Mean patient age was 61.3 ± 10.5 years and 19.2% (n = 206) presented with non-ST-elevation myocardial infarction (NSTEMI). Lesions were 3.2 ± 0.3 mm in diameter and 14.9 ± 4.2 mm long; 5.1% (n = 57) were bifurcation lesions. Device success was 97.3% (n = 1,129) and procedure success 98.9% (n = 1,063). The Kaplan-Meier estimate of TLF at 12 months was 4.3% [95% confidence interval, CI: 3.2, 5.7] consisting of 3.9% target lesion revascularizations, 0.2% cardiac death, and 1.1% target-vessel myocardial infarction. Definite/probable scaffold thrombosis occurred in five patients (0.5% [95% CI: 0.2, 1.1]), thereof four after early discontinuation of antiplatelet/anticoagulation therapy.

CONCLUSION

BIOSOLVE-IV confirms the safety and performance of the Magmaris scaffold in a large population with excellent device and procedure success and a very good safety profile up to 12 months in a low-risk population.

Recent advances and directions in the development of bioresorbable metallic cardiovascular stents: Insights from recent human and in vivo studies

Over the past two decades, significant advancements have been made regarding the material formulation, iterative design, and clinical translation of metallic bioresorbable stents. Currently, magnesium-based (Mg) stent devices have remained at the forefront of bioresorbable stent material development and use. Despite substantial advances, the process of developing novel absorbable stents and their clinical translation is time-consuming, expensive, and challenging. These challenges, coupled with the continuous refinement of alternative bioresorbable metallic bulk materials such as iron (Fe) and zinc (Zn), have intensified the search for an ideal absorbable metallic stent material. Here, we discuss the most recent pre-clinical and clinical evidence for the efficacy of bioresorbable metallic stents and material candidates. From this perspective, strategies to improve the clinical performance of bioresorbable metallic stents are considered and critically discussed, spanning material alloy development, surface manipulations, material processing techniques, and preclinical/biological testing considerations. STATEMENT OF SIGNIFICANCE: Recent efforts in using Mg, Fe, and Zn based materials for bioresorbable stents include elemental profile changes as well as surface modifications to improve each of the three classes of materials.  Although a variety of alloys for absorbable metallic stents have been developed, the ideal absorbable stent material has not yet been discovered. This review focuses on the state of the art for bioresorbable metallic stent development. It covers the three bulk materials used for degradable stents (Mg, Fe, and Zn), and discusses their advances from a translational perspective. Strategies to improve the clinical performance of bioresorbable metallic stents are considered and critically discussed, spanning material alloy development, surface manipulations, material processing techniques, and preclinical/biological testing considerations.

Serial invasive imaging follow-up of the first clinical experience with the Magmaris magnesium bioresorbable scaffold

Objectives

To assess the performance of the commercially available Magmaris sirolimus‐eluting bioresorbable scaffold (BRS) with invasive imaging at different time points.

Background

Coronary BRS with a magnesium backbone have been recently studied as an alternative to polymeric scaffolds, providing enhanced vessel support and a faster resorption rate. We aimed to assess the performance of the commercially available Magmaris sirolimus‐eluting BRS at different time points.

Methods

A prospective, single‐center, nonrandomized study was performed at the Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands. Six patients with stable de novo coronary artery lesions underwent single‐vessel revascularization with the Magmaris sirolimus‐eluting BRS. Invasive follow‐up including intravascular imaging using optical coherence tomography (OCT) was performed at different time points.

Results

At a median of 8 months (range 4–12 months) target lesion failure occurred in one patient. Angiography revealed a late lumen loss of 0.59 ± 0.39 mm, a percentage diameter stenosis of 39.65 ± 15.81%, and a binary restenosis rate of 33.3%. OCT showed a significant reduction in both minimal lumen area (MLA) and scaffold area at the site of the MLA by 43.44 ± 28.62 and 38.20 ± 25.74%, respectively. A fast and heterogeneous scaffold degradation process was found with a significant reduction of patent struts at 4–5 months.

Conclusions

Our findings show that the latest iteration of magnesium BRS suffers from premature dismantling, resulting in a higher than expected decrease in MLA.