Long-term clinical, angiographic, and optical coherence tomography findings of Mg-based bioresorbable scaffold in patients with acute coronary syndrome.

BACKGROUND This study sought to evaluate the clinical outcomes of patients treated with magnesium-based bioresorbable scaffolds (MgBRS) in the context of acute coronary syndromes (ACS) at long-term follow-up (24 months). The study also aims to investigate the MgBRS performance by angiography and the healing and bioresorption pattern by optical coherence tomography (OCT) at 18 months. METHODS Between December 2016 and December 2018, a total of 90 patients admitted for ACS and treated with MgBRS (Magmaris, Biotronik AG, Bulach, Switzerland) were enrolled in a multicenter prospective study. Clinical follow-up was performed in all patients at 24 months and angiographic and OCT follow-up in 51.5% of patients at 18 months. Serial OCT was available in 33 patients (36.7%). RESULTS At a 2-year follow-up, 88.8% were free of symptoms, no cardiac death was reported, and the device-oriented composite event (DOCE): consisting of cardiac death, target vessel myocardial infarction, and target lesion revascularization (TLR) was 13.3%. Stent thrombosis and TLR were observed in 2.2 and 11.1%, respectively. Binary restenosis was observed in 21.7% of cases and in-stent late lumen loss was 0.61 ± 0.75 mm. By serial OCT imaging, the minimal lumen area was significantly reduced greater than 40% (from 6.12 ± 1.59 to 3.5 ± 1.55 mm2, p < .001). At follow-up, area stenosis was 44.33 ± 23.07% and half of the patients presented indiscernible struts. The principal observed mechanism of restenosis was scaffold collapse. CONCLUSIONS At long-term follow-up, MgBRS implantation in ACS patients showed a high rate of DOCE, mainly caused by clinically driven TLR. MgBRS restenosis was caused by scaffold collapse in most of the cases.