Post-transplant surveillance for acute rejection and allograft vasculopathy by echocardiography: Usefulness of myocardial velocity and deformation imaging.

Diagnosing and monitoring acute rejection (AR) and cardiac allograft vasculopathy (CAV) is essential for graft and transplant patient survival and, consequently, a major objective for heart transplant patient surveillance. Because functionally relevant CAV can arise and progress without clinical symptoms and sub-clinical ARs can facilitate the development of CAV, standard surveillance of AR and CAV includes routine endomyocardial biopsy (EMB) and coronary angiography (CA) screenings at pre-defined time intervals. However, these invasive screenings (distressing and risky for the patients) cannot solely diagnose all sub-clinical AR episodes and also not always detect coronary stenoses before a clinical event. Additional close-meshed, non-invasive AR and CAV surveillance strategies are therefore mandatory. After the introduction of tissue Doppler imaging (TDI) and strain imaging for myocardial wall motion and deformation analysis, echocardiography became particularly promising for that purpose. Allowing quantification of minor myocardial dysfunction not detectable by standard echocardiography, TDI and strain imaging can reveal sub-clinical AR. Thus, these approaches can be a valuable supplement to EMB, enabling more efficient AR monitoring with fewer EMBs (only diagnostic EMBs) instead of unnecessary and distressing routine EMB screenings. Their use can also improve therapeutic decisions and monitoring of myocardial function during anti-rejection therapy. Myocardial velocity and deformation imaging is also suited to early detection of myocardial dysfunction induced by CAV and may be useful for prognostic evaluation and timing of CAs, with an aim of reducing the number of routine CA screenings. However, further studies are necessary before specific recommendations for the use of TDI and strain imaging for CAV surveillance become possible.