Intravascular ultrasound for assessment of coronary allograft vasculopathy.

Coronary allograft vasculopathy (CAV) is the major factor limiting the long-term survival after cardiac transplantation. Intravascular ultrasound (IVUS) markedly improved our knowledge about in vivo morphology of CAV by precise determination of vessel morphology. In vivo studies with IVUS demonstrated that transplant vasculopathy may present with a very heterogeneous morphology suggesting a dual etiology of transplant coronary artery disease. The high incidence of donor-transmitted atherosclerosis and its role in further progression of CAV could be demonstrated by the use of IVUS. Beside intimal hyperplasia, adaptive remodeling processes of vessel and lumen geometry may have physiologic and prognostic importance. IVUS is so far the only method that allows the evaluation of compensatory enlargement and shrinkage of coronary vessels in CAV. IVUS investigations allow the assessment of CAV progression in early angiographically not visible stages. The influence of different medical treatment regimens on CAV progression can be quantified. Further studies showed that IVUS parameters may have prognostic impact on subsequent clinical events and angiographic progression of CAV. However, besides all the diagnostic information provided by IVUS, the main application of this method is currently in the field of clinical research.