Optical coherence tomography for serial in vivo imaging of aortic plaque in the rabbit: a preliminary experience

BACKGROUND: In this pilot feasibility study, we aimed to establish a reproducible means of performing serial optical coherence tomography (OCT) procedures in the abdominal aorta of the cholesterol-fed rabbit. METHODS: Eight cholesterol-fed New Zealand White rabbits were assigned to abdominal aortic balloon injury at baseline (n=6) or as controls (n=2). Three of the balloon injured rabbits received statins from weeks 6 to 12 post balloon injury. OCT of the abdominal aorta in each rabbit was performed at baseline±week 6±week 12 via alternate vascular access points (left or right femoral artery or left carotid artery). OCT sequences were analysed to derive an indexed plaque volume and other OCT measures of plaque complexity, and results were compared between groups. Histopathological correlations with OCT images were made following terminal procedures. RESULTS: Of the 16 OCT procedures in these rabbits (6 at baseline, 4 at 6 weeks, 6 at 12 weeks), excellent and analysable images were obtained on 15 occasions (94%). Inability to obtain adequate arterial access for the OCT catheter was the major experimental limitation encountered in the early part of our experience. Balloon injured rabbits developed larger volume and more complex plaque than non-balloon injured rabbits on all OCT indices measured (eg, both mean plaque volume and lumen stenosis were approximately double in the balloon injured group, p<0.0001). A significant correlation between 12 week measures of plaque area by OCT and histology was demonstrated (Pearson correlation coefficient: 0.992, p<0.0001). CONCLUSIONS: Our preliminary experience suggests that serial OCT of the abdominal aorta in the New Zealand White rabbit is feasible and a potentially promising means of performing serial studies of aortic atherosclerosis.