[Doppler echocardiography after heart transplantation]

Acute rejection, graft atherosclerosis and infections are the major causes of morbility and mortality after heart transplantation. Therefore clinical follow-up after heart transplantation is usually focused on the early diagnosis and treatment of these complications. The early recognition of acute rejection episodes in cardiac allograft recipients remains a major challenge during follow-up after heart transplantation. The standard method used to identify rejection is endomyocardial biopsy, but this technique shows some important inherent limitations. Even if noninvasive methods are generally considered inaccurate in the early diagnosis of acute rejection, echocardiography is routinely used in the surveillance of heart transplant recipients to monitor allograft function. Furthermore it may be used to screen significant acute rejection episodes, because it can identify several morphologic and functional changes that are related to acute rejection: increase in left ventricular myocardial thickness, changes in ultrasonic texture, pericardial effusion, systolic and diastolic dysfunction. In this setting it is very useful to perform serial echocardiographic examinations, because the changes of echocardiographic and Doppler parameters in comparison with previous examination in each individual patient can be accurate in detecting acute rejection and evaluating the response after immunosuppressive treatment. The development of coronary artery disease (CAD) is the major factor limiting long-term survival. Serial coronary artery angiography remains the only effective diagnostic tool for detecting CAD, while noninvasive tests commonly used in atherosclerotic heart disease are considered inaccurate, due to their low sensitivity. However several studies reported a high accuracy of dobutamine stress echocardiography in the diagnostic and prognostic assessment of CAD. Furthermore, rest wall motion abnormalities and left ventricular systolic dysfunction can identify patients with significant CAD and worse prognosis. In conclusion, echocardiography cannot supplant invasive methods for monitoring acute rejection and CAD, but it is a useful tool for surveillance after heart transplantation.