Early restenosis of resorbable magnesium scaffolds: Optical coherence tomography findings.

Resorbable Magnesium Scaffolds (RMS) represent an interesting alternative to current drug-eluting stents. Current data from clinical trials seems to confirm good performance of these new devices with low rates of late device failure. Little is known about mechanisms leading to RMS failure. Herein, we present the first description of an early RMS in-scaffold restenosis. Optical coherence tomography (OCT) analysis at implantation detected acute non-severe malapposition and underexpansion as main promoters of RMS failure. OCT during in-scaffold restenosis intervention confirmed early severe neointimal proliferation and RMS late recoil and dismantling as the main mechanisms of device failure. We hypothesize that the fast resorption process of RMS may lead to an early loss of radial strength, that could favor late recoil, acquired underexpansion, device dismantling and might interact with distribution of sirolimus. This case also illustrates that OCT is pivotal to unravel both acute and acquired mechanisms related to RMS failure.