Role of Dobutamine Stress Echocardiography for Diagnosis of Cardiac Allograft Vasculopathy

Abstract

CARDIAC allograft vasculopathy (CAV) remains a main factor limiting long-term survival after heart transplantation (HTX). Manifestations of CAV include focal stenoses as well as diffuse longitudinal involvement of vessels and small vessel disease. The clinical diagnosis is difficult, as the heart is denervated and usually remains without functionally relevant reinnervation. Routine coronary angiography is therefore the mainstay of diagnosis of CAV; this technique, however, shows a pure luminogram and is not able to detect early changes of CAV, ie, changes in the thickness of the vessel wall. Intravascular ultrasound (IVUS) has emerged as most sensitive invasive method for diagnosis of CAV. IVUS, however, can only be used to analyze the major epicardial vessels and is not able to investigate the entire coronary artery tree. In addition, both angiography and IVUS are invasive, costly and not free of risk. Several tests employed for noninvasive detection of CAV have proven unsatisfactory. In some studies, this may be related to the mode of provocation of ischemia: physical exercise may be not adequate after HTX, as the chronotropic response to exercise is blunted due to denervation. Stress tests using vasodilators as dipyridamole, which induces relative differences of perfusion, may be less reliable in diffuse CAV, but appear to be superior to exercise tests. Pharmacologic stress testing using dobutamine can overcome the problems associated with other stress modalities. Indeed, dobutamine stress echocardiography (DSE) has emerged as the most promising noninvasive method for diagnosis of CAV. This article reviews our experience and published data on assessment of CAV by DSE.