Magmaris resorbable magnesium scaffold versus conventional drug-eluting stent in ST-segment elevation myocardial infarction: 1-year results of a propensity score matching comparison

Magmaris® (Biotronik AG, Switzerland) is the first RMS and early experience has shown promising results in stable coronary artery disease. Acute coronary syndromes have been hypothesized as a potential target group for bioresorbable scaffolds, but the efficacy and safety of RMS has not been extensively studied in ST-segment elevation myocardial infarction (STEMI). BEST-MAG is a prospective multicenter trial designed to evaluate optical coherence tomography (OCT-)guided implantation of resorbable magnesium scaffold (RMS) in STEMI. Consecutive STEMI patients fulfilling inclusion/exclusion criteria were treated with RMS following a standardized OCT-based implantation technique including systematic pre- and post-dilatation, and baseline plus final OCT imaging. The primary endpoint was a device oriented composite endpoint (DOCE) including cardiac death, target vessel myocardial infarction (TV-MI) and target lesion revascularization (TLR) within 12 months. Clinical outcomes were compared after propensity score matching (PSM) to the results of the randomized controlled BIOSTEMI trial comparing biodegradable polymer sirolimus eluting (BP-SES) and durable polymer everolimus eluting stents (DP-EES) in STEMI. Between 15th February 2019 and 25th May 2020, 30 patients were included in 5 centers. Procedural success was achieved in all cases based on OCT control with final scaffold expansion of 82 ± 11%. At twelve-months, DOCE rate was 13.3% (n = 4), including 4 cases of TLR (13.3%) and one case of TV-MI (3.3%). No cardiac death occurred, and no scaffold thrombosis (ScT) was observed. Using PSM, DOCE rates in BP-SES and DP-EES groups were 10% and 6% respectively and TLR rates were 3.3% and 0.0%. In this study, OCT-guided RMS implantation in selected STEMI patients appeared feasible but was associated with numerically higher rates of TLR as compared with conventional drug-eluting stents, although the limited number of patients included in this analysis does not allow drawing statistically significant conclusions. [Display omitted] •OCT-guided RMS implantation in the setting of p-PCI for selected STEMI patients appears to be feasible.•Compared with conventional DES, RMS implantation in STEMI patients was associated with a trend toward higher TLR rate at 1-year follow-up.•Future iterations of the device might improve results through higher radial force, lower strut thickness and longer scaffolding durations.