Increased coronary lipid accumulation in heart transplant recipients with prior high-grade cellular rejection: novel insights from near-infrared spectroscopy.

Cardiac allograft vasculopathy is a major cause of morbidity and mortality among patients after heart transplantation. We sought to assess the amount of lipid accumulation in the coronary arteries of transplant patients according to rejection grade. Overall, 39 consecutive heart transplant recipients undergoing annual routine surveillance coronary angiography underwent near-infrared spectroscopy and intravascular ultrasound imaging of 1 coronary artery. Rejection history was graded according to the International Society of Heart and Lung Transplantation (ISHLT) classification as none/mild/moderate-grade rejection (ISHLT 0, 1A/1B, or 2) compared to high-grade rejection (≥3A). Patients with prior history of high-grade rejection had larger plaque burden in the distal coronary segments [45.7 % (25.5-63.7) vs 25.1 % (19.9-37.8), p = 0.02] and a higher maximum lipid core burden index in any 4-mm long segment (maxLCBI(4mm)) [243 (91-400) vs 41 (1-170), p = 0.016] as compared with patients with prior history of none/mild/moderate-grade rejection. By multivariable linear regression analysis, prior history of high-grade rejection was an independent predictor for maxLCBI(4mm). A maxLCBI(4mm) >200 distinguished prior history of high-grade from none/mild/moderate rejection with a sensitivity of 61.5 % and specificity of 84.6 %. The current study demonstrates that the coronary arteries of post heart-transplant patients with a prior history of high-grade cellular rejection have increasing amounts of lipid-rich plaque. MaxLCBI(4mm) >200 might differentiate patients with previous high-grade cellular rejection from heart transplant recipients with none/mild/moderate-grade rejection.

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 spectroscopy-intravascular 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 maxLCBI4mm [4-mm long segment with maximum lipid core burden index (LCBI)] and corresponding IVUS parameters were compared. MaxLCBI4mm 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 maxLCBI4mm and maximum plaque burden in both groups, but atherosclerotic patients demonstrated a smaller maxLCBI4mm 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.