What exactly, regression of atherosclerosis or foreign body reaction with hyaline arteriosclerosis, drives transient scaffolding of coronary arteries? A pooled analysis of observational ABSORB studies with a serial multimodality imaging substudy of ABSORB cohort B1 trial.

OBJECTIVES: We aimed to estimate the trends of the artery remodeling after transient scaffolding.

BACKGROUND: At least 2.62% reduction of the per cent atheroma volume (PAV) or plaque burden (PB) performed in ABSORB B trial at 60months.

METHODS: The detailed multiple serial imaging evaluation was performed by intravascular ultrasound (IVUS) in comparison with quantitative coronary angiography (QCA), multislice CT (MSCT) and optical coherence tomography (OCT) thru 24months in the ABSORB cohort B1 trial (n=45) with the pooled analysis in ABSORB A and B trials (n=131).

RESULTS: The growth of PB achieved 1.63% at 24months in ABSORB A trial, with a maximum 2.62% reduction (p<0.22) at 60months in B2 trial. An accuracy was highest for OCT (96.6%), and the lowest - in MSCT with a 62.0% trueness. The IVUS analysis of 32 cohort B1 patients demonstrated insignificant decrease in PB between 6months and 2years with a 2.54% gain in 24 patients (p=0.08) and the area enlargement of the fibrous tissue (48.52%, p=0.02). Eight patients performed a 2.67% reduction of PB (p=0.28). The phenomenon of the window of the external elastic membrane enlargement (PB of 30.26-54.86%) was documented. The moderate correlation (p<0.05) was evaluated between IVUS PB and stenosis (r=0.25), IVUS and MSCT lumen (r=0.40), IVUS PB and MSCT lumen (r=0.38), VH-IVUS MLA with fibrous (r=0.25), necrotic core and fibro-fatty tissue (r=0.20).

CONCLUSION: The implantation of bioresorbable scaffold causes a trend toward reduction of PB with atheroprotective artery remodeling amid hyaline arteriosclerosis and foreign body reaction.