Multicenter assessment of coronary allograft vasculopathy by intravascular ultrasound-derived analysis of plaque composition

Background: Coronary allograft vasculopathy is a severe complication of heart transplantation. We used virtual histology intravascular ultrasound to characterize plaque burden and tissue composition over time in heart transplant recipients. Methods: We recruited patients undergoing heart transplantation in four centers in Europe and the US between 2004 and 2006. We used intravascular ultrasound to obtain morphological plaque measurements and to perform virtual histology in the left anterior descending coronary artery. Data were characterized according to the duration between transplantation and intravascular ultrasound assessment: ≤24, >24-60, >60-120 and >120-192 months. Results: We assessed vessels from 152 patients (mean age 58 ± 12 years) a mean of 70 ± 53 months (range 1 week to 16 years) after transplantation. Plaque burden of >40% was observed in 26% of vessels analyzed, with increases from baseline being seen in all time categories. If assessed >24 months after transplantation, necrotic core and dense calcified volumes were significantly greater than at baseline (P = 0.0005 and P = 0.01, respectively). Time since heart transplantation and donor age and recipient age were independent predictive factors of increased necrotic core content. Necrotic core volume >2.01 mm³, diabetes mellitus, donor age older than 40 years, follow-up from transplantation longer than 5 years and recipient age older than 58 years were associated with the need for revascularization. Conclusions: In coronary allograft vasculopathy, plaque burden and composition change over time and seem to affect clinical outcome. This relationship might facilitate identification of high-risk patients in whom the value of more aggressive medical therapy should be tested.