Mechanism of Drug-Eluting Absorbable Metal Scaffold Restenosis: A Serial Optical Coherence Tomography Study

Area of Science:

• Cardiovascular research
• Medical device technology
• Interventional cardiology

Background:

• Restenosis following implantation of bioabsorbable sirolimus-eluting metallic scaffolds (Magmaris) is a clinical concern.
• The precise mechanisms driving restenosis, specifically the roles of late scaffold recoil and neointimal hyperplasia, remain incompletely understood.

Purpose of the Study:

• To investigate the underlying pathomechanisms of restenosis in Magmaris scaffolds.
• To differentiate the contributions of late scaffold recoil and neointimal hyperplasia to late lumen loss (LLL).

Main Methods:

• Analysis of serial optical coherence tomography (OCT) and angiography data from patients in the BIOSOLVE-II trial.
• Patients were categorized based on in-scaffold LLL (<0.5 mm or ≥0.5 mm) at 6-month or 1-year follow-up.
• Quantification of late absolute scaffold recoil and neointimal hyperplasia area using OCT.

Main Results:

• Late scaffold recoil was significantly greater in patients with LLL ≥0.5 mm compared to those with LLL <0.5 mm (1.48±1.20 mm² vs 0.53±0.68 mm², P<0.001).
• Neointimal hyperplasia area was also larger in the LLL ≥0.5 mm group at follow-up (1.68±0.34 mm² vs 1.47±0.33 mm², P=0.013).
• Late scaffold recoil varied significantly with plaque morphology (highest in fibrotic lesions), whereas neointimal hyperplasia did not.

Conclusions:

• Late scaffold recoil is a significant contributor to LLL in sirolimus-eluting absorbable metal scaffolds, alongside neointimal hyperplasia.
• The degree of late scaffold recoil is influenced by the patient's underlying plaque characteristics.
• These findings provide critical insights into scaffold behavior and restenosis development, informing future device design and clinical management.