In vivo comparison between cardiac allograft vasculopathy and native atherosclerosis using near-infrared spectroscopy and intravascular ultrasound

Aims The aim was to compare cardiac allograft vasculopathy to native atherosclerosis by near-infrared spectroscopyintravascular ultrasound (NIRS-IVUS). Methods and results Twenty-seven atherosclerotic (non-transplant) patients and 28 heart transplant recipients undergoing routine surveillance coronary angiography underwent NIRS-IVUS imaging of the left anterior descending coronary artery. In each proximal, middle, and distal coronary artery segment, the maxLCBI_4mm [4-mm long segment with maximum lipid core burden index (LCBI)] and corresponding IVUS parameters were compared. MaxLCBI_4mm was significantly greater among atherosclerotic patients than the transplant patients in both proximal and middle coronary artery segments, but not in the distal segment. There was a positive linear correlation between maxLCBI_4mm and maximum plaque burden in both groups, but atherosclerotic patients demonstrated a smaller maxLCBI_4mm than transplant recipients among segments with plaque burden ,40%. Among segments with a maximum plaque burden ≥40%, native-atherosclerosis patients had a greater maxLCBI4mm compared with transplant patients (P = 0.015). Calcification was present in 72.9% of native atherosclerosis and 14.7% of transplant segments (P < 0.001). Among the 165 analysed segments, prevalence of lipid-rich plaque (LRP) with superficial attenuation (30.9 vs. 1.2%, P < 0.001) or calcified LRP (13.6 vs. 2.4%, P = 0.03)was significantly greater in native atherosclerosis compared with transplant patients.Conversely, the proportion of segments with non-LRP (46.4 vs. 11.1%, P < 0.001) was higher in transplant patients. Conclusion NIRS-IVUS imaging demonstrated early and accelerated lipid accumulation with smaller plaque burden and less calcium in patients after heart transplant when compared with patients with native atherosclerosis.