Virtual histology intravascular ultrasound assessment of cardiac allograft vasculopathy from 1 to 20 years after heart transplantation

Abstract

Background: Cardiac allograft vasculopathy (CAV) is the main cause of graft loss and death in heart transplant (HTx) recipients surviving >1 year. There is a dual etiology for coronary disease in HTx: classic atherosclerosis and an immunologically mediated disease. Intravascular ultrasound (IVUS) is highly sensitive for CAV detection; however, gray-scale IVUS is of limited value for identification of specific plaque components. We sought to characterize graft coronary artery disease by means of IVUS-virtual histology (IVUS-VH) at different time-points of follow-up and to correlate plaque composition with clinical factors.

Methods: In our study we included 67 patients, who were 7.6 +/- 5.7 years post-HTx. IVUS gray-scale evaluation was performed on all patients. IVUS-VH analysis was done in those patients showing intimal thickening >0.5 mm at the three more significant lesions (three cross-sections for each) of the left anterior descending artery.

Results: IVUS-VH analysis was obtained done on 58 patients (86.5%). We found a significant correlation between time of HTx and IVUS gray-scale parameters (plaque area and plaque burden), with both increasing over time. We also found a significant correlation between time and IVUS-VH-derived plaque components, necrotic core and calcium, which increased with time, and fibrous and fibrofatty components, both decreased at follow-up. IVUS-VH results were also related to donor age and cardiovascular risk factors.

Conclusions: We observed a time-related change in IVUS-VH-derived plaque composition. Necrotic core and calcium, typical atheromatous components, become more prevalent with time after HTx, especially when influenced by cardiovascular risk factors. The presence of a necrotic core in the early stages was linked to older donor age.