Optical coherence tomography and histopathological assessment of delayed arterial healing after drug-eluting stent implant in a pig coronary model

Abstract

BackgroundDelayed healing, such as persistent inflammation and fibrin deposition, and vascular dysfunction after drug-eluting stent has been reported. Histological validation of coronary optical coherence tomography (OCT) morphology has not yet been done. MethodsSirolimus eluting stents (SES, n=8) and bare metal stents (BMS n=8) were implanted in pig coronary arteries. One month after implantation, an acetylcholine challenge test and OCT were performed. The OCT texture pattern of the neointima was classified into one of the three categories; Layered type, Homo type, and Hetero type. Hearts were harvested for histopathological scoring of inflammation and intramural thrombus. ResultsInflammation and intramural thrombus scores were higher in the Hetero type than in the Layered type and Homo type. OCT intensity of the Homo type was higher than that of the Layered type and Hetero type. Most SES were of the Hetero type. Conversely, most BMS were of the Homo type. SES exhibited higher inflammation and intramural thrombus than BMS (1.72±0.89 vs 1.00±0.00, P=0.0003, 2.39±0.70 vs 0.92±0.28, P<0.001 respectively). After acetylcholine injection, the diameter change was 4.31±4.80% for SES versus −3.68±6.81% for BMS (P=0.024). ConclusionsThe Hetero type texture pattern in OCT images was associated with histological inflammation and intramural thrombus predominantly found in SES, and is related to endothelial dysfunction.