PurposeThe aim of this study was to evaluate the safety and efficacy of the Fantom BRS 6 months after implantation using the optical coherence tomography (OCT) imaging.MethodsTwenty STEMI patients treated with a sirolimus‐eluting Fantom BRS were enrolled into a prospective, single-arm, serial observational study. The scaffold sizing, positioning and optimisation were guided by OCT imaging. The primary endpoint was device‐orientated composite endpoints (DOCE), comprised of cardiac death, target-vessel-related myocardial infarction and target lesion failure. To evaluate the device performance at the scaffold level, we performed a quantitative coronary angiography (QCA) and OCT imaging at 6 months.ResultsThe primary endpoint did not occur in any patient within the 6-month follow‐up. There were no major adverse cardiac events (MACEs) or DOCEs, no cases of scaffold thrombosis, target lesion revascularization and no deaths. In QCA, we observed a decrease in the minimum and mean lumen diameter in the in-scaffold region and in the proximal and distal peri-scaffold region. Similarly, the minimum lumen area and reference vessel diameter had decreased in both QCA and OCT. The OCT imaging showed improvement in the expansion index and malposition rate.ConclusionA serial 6-month OCT imaging after implantation of a third-generation Tyrocore-based bioresorbable coronary scaffold indicated good coverage of the struts with excellent healing of the scaffold, low neointima growth and no signs of neoatherosclerosis.