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

Abstract

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.

Keywords: Magmaris; bioresorbable scaffold (BRS); magnesium; outcome; percutaneous coronary intervention; scaffold thrombosis; stent.

Conflict of interest statement

MB has received speaker and/or consultant fees from Abbott Vascular, Amgen, AstraZeneca, Abiomed, Amgen, Bayer, Daiichi Sankyo, Mundipharma, and SIS Medical. RK has received institutional grants from Abbott, Biosense Webster, Biotronik, Boston Scientific, Medtronic, and SIS Medical and serves as a consultant for Biosense Webster and Biotronik. FC has received speaker and consulting fees from Abbott Vascular, Abiomed, and SIS Medical. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2022 Bossard, Madanchi, Avdijaj, Attinger-Toller, Cioffi, Seiler, Tersalvi, Kobza, Schüpfer and Cuculi.

Figures

Figure 1

The Kaplan–Meier curves for the device-oriented composite endpoint (DoCE) and target lesion revascularization (TLR) over time.

Figure 2

Hallmark OCT findings encountered in patients with the Mg-BRS-related target lesion failures: (A) scaffold collapse; (B) uncontrolled device dismantling. (A) This OCT image shows a collapsed scaffold with seemingly “free-floating” struts (arrow), which are no longer embedded and apposed to the coronary artery's wall. Also, the inner lumen appears to have restenosis with significant luminal irregularities and tissue protrusion. (B) This illustrates an incompletely dismantled Mg-BRS with residuals of struts protruding into the vascular lumen (arrow). Also, the intima appears partially irregular (1–5 o'clock). Mg-BRS, magnesium-based sirolimus-eluting bioresorbable scaffold; OCT, optical coherence tomography.

Figure 3

Case with TLR 42 days after implantation of the 2 Mg-BRS. Angiographic and OCT results of a case that required TLR. (A) By angiographic measures, a good result was achieved after implantation of the 2 Mg-BRS devices to the left anterior coronary artery; (B) This shows the angiography of the left anterior descending artery 42 days after the scaffold implantation, including serial segments (C,E,F) with significant luminal narrowing [>75% by Quantitative Coronary Angiography (QCA)]; (C,F) These images illustrate device collapse and uncontrolled dismantling associated with excessive tissue formation and significant lumen loss; (D) This segment shows eccentric remodeling of the artery wall after complete degradation of the Mg-BRS; (E) On OCT, the Mg-BRS seems completed degraded in this segment of left anterior descending (LAD). Mg-BRS, magnesium-based sirolimus-eluting bioresorbable scaffold; OCT, optical coherence tomography. *: denotes the scaffold and arrow: denotes the vessel lumen.

Figure 4

Case vignette of a patient treated with the 2 Mg-BRS, depicting long-term scaffold persistence and negative vessel remodeling. A 46-year-old patient presented to the emergency department with an acute anterior ST-segment elevation myocardial infarction (STEMI). On the coronary angiogram, a complete occlusion of the mid LAD artery was observed (A). After predilatation with a non-compliant balloon (2.5 mm × 20 mm, 14 atm), the 2 Magmaris BRS (3 mm × 25 mm and 3.5 mm × 25 mm) were successfully implanted (B). The patient presented 4 years later with chest pain during physical activity [chronic coronary syndrome II (CCS II)]. On the coronary angiogram (C), we found an aneurysmatic proximal to mid LAD without relevant stenosis. On OCT (D), scaffold remnants were observed as an expression of incomplete scaffold degradation. *: complete vessel occlusion, arrow: coronary aneurysma, and arrowhead: scaffold remnants.