Coronary Artery Bypass at a Drug-Eluting Resorbable Magnesium Scaffold Site in a Porcine Model

Background/purpose: Coronary artery bypass graft (CABG) in the presence of metallic permanent stents may be challenging. We explored the feasibility of performing CABG in 1-year Magmaris resorbable scaffold implants in healthy Yucatan pigs.

Methods/materials: One animal received Magmaris 3.0 × 20.0-mm scaffolds in the left anterior descending (LAD), left circumflex (LCx), and right coronary arteries (RCA) under fluoroscopy. After 376 days, the animal underwent off-pump CABG at the scaffold site, including a single "end-to-side" anastomosis involving the right internal mammary artery (RIMA) to the LAD. The LAD was grafted in the territory of the previous scaffold as demonstrated by angiogram and the D1 and D2 landmarks.

Results: Digital radiography of the intact heart showed all degraded scaffolds widely expanded and uniformly positioned in the vessel wall in their expected locations. The proximal and distal radiopaque markers were clearly visible. The anastomosis was clearly identified by titanium branch clips, and the RIMA bypass was surrounded by connective tissue, which was further dissected before micro-computed tomography (CT) imaging. On the micro-CT images, calcification of the device was rare. The anastomosis site appeared intact, and the LAD at treatment site was widely open.

Conclusions: Our limited early feasibility study in a healthy animal demonstrates the practicality of CABG in a Magmaris scaffold after 1 year despite the persistence of visible degradation product, suggesting that the prior coronary device implant does not preclude future coronary surgery.