Advanced Cardiac Imaging in Cardiac Allograft Vasculopathy

Cardiac allograft vasculopathy (CAV) is a process of both immune and non-immune mediated thickening of the heart arteries of transplanted hearts. CAV limits the long term survival of heart transplant patients and is one of the common causes of death in the late post transplant period. Current methods of detecting CAV rest with invasive cardiac catheterization which carry repeated risks, as this test needs to be performed periodically through the life of a heart transplant patient. Traditional methods of coronary angiography identify CAV late in its course and is a crude method of evaluating coronary anatomy in heart transplant patients. Intravascular ultrasound is an additive tool that is able to detect early CAV before it becomes angiographically apparent, but still requires invasive cardiac catheterization to perform. However, it also limits assessment to the major epicardial arteries and does not give any information regarding the smaller branch vessels and cardiac microvasculature. Advances in cardiac CT and cardiac MRI hold potential to evaluate for CAV non-invasively. In addition, perfusion techniques may provide additional functional information regarding the status of the microvascular. In this pilot study, we aim to demonstrate the feasibility of cardiac CT and cardiac MRI with and without perfusion protocols, in patients post-heart transplant and to describe and compare CT and MRI findings in patients with established CAV versus those with no CAV, as diagnosed by standard invasive methods.