Vascular response following implantation of the third-generation drug-eluting resorbable coronary magnesium scaffold: an intravascular imaging analysis of the BIOMAG-I first-in-human study.

Background: The 12-month outcomes of BIOMAG-I - the first-in-human study investigating the third-generation drug-eluting resorbable magnesium scaffold (DREAMS 3G) - showed promising results regarding clinical outcomes and late lumen loss.
Aims: The current study aimed to investigate vascular healing parameters assessed by optical coherence tomography (OCT) and intravascular ultrasound (IVUS), focusing on strut visibility, vessel and scaffold areas, and neointimal growth patterns.
Methods: This is a BIOMAG-I substudy including patients with available serial OCT and IVUS data. We conducted a frame-based analysis of OCT findings in conjunction with IVUS-derived vessel and scaffold areas, evaluating the qualitative and quantitative aspects of vascular healing.
Results: Among the 116 patients enrolled in this trial, 56 patients treated with DREAMS 3G were included in the analysis. At 12 months, OCT imaging revealed that 99.0% of the struts were invisible, and no malapposed struts were depicted. While the vessel area showed no significant difference between the timepoints, the minimum lumen area significantly decreased from post-percutaneous coronary intervention to 6 months (6.88 mm ² to 4.75 mm ² ; p<0.0001), but no significant changes were observed between 6 and 12 months. Protruding neointimal tissue (PNT) - a unique neointimal presentation observed following resorbable magnesium scaffold implantation - was observed in 89.3% of the study patients at 12 months, and its area exhibited a 47.4% decrease from 6 to 12 months.
Conclusions: This imaging substudy revealed that, at 12-month follow-up, virtually all struts of the DREAMS 3G scaffold became invisible, without evident malapposition. The vascular healing response to DREAMS 3G implantation also appeared favourable up to 12 months, which is indicated by advanced strut degradation and spontaneous regressing PNT between 6 and 12 months.