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.