The Role of Echocardlography In the FoIIow-Up of Orthotopic Heart Transplant Patients
Echocardiography is being used increasingly in the follow-up of patients after orthotopic heart transplantation. Doppler echocardiographic parameters of diastolic function [isovolumic relaxation time (IVRT), pressure half time (PHT), and early peak mitral inflow velocity (M1)] have been shown to be useful in detecting moderate to severe allograft rejection. Using each individual patient as his/her own control, accounting for the effects of recipient atrial contraction and time from transplant, a decrease in the IVRT or PHT Lx 15% is considered diagnostic of diastolic dysfunction and, hence, is an echocardiographic diagnosis of rejection. The sensitivity of these parameters to predict rejection approaches 80–90% with a specificity of 80–90%. Echocardiography is the procedure of choice in the diagnosis and follow-up of pericardial effusion and tricuspid regurgitation after transplantation. The presence of tricuspid regurgitation seems to be related to and a complication of the number of endomyocardial biopsies performed during the first year after transplantation. Dobutamine stress echocardiography is being used increasingly in the noninvasive diagnosis of transplant coronary artery disease. Using angiography as the “gold standard,” dobutamine stress echocardiography has a sensitivity of 80– 96% in the detection of transplant coronary artery disease. Echocardiographic measures of both systolic and diastolic function, and the development of regional wall motion abnormalities during dobutamine stress echocardiography, have all been shown to be useful predictors of mortality and the occurrence of cardiac events late after transplantation.