Dobutamine stress echocardiography predicts cardiac events in heart transplant patients

Cardiac transplantation is an accepted treatment modality for end-stage heart failure. Coronary artery disease remains a major cause of mortality in the long term after heart transplantation. Despite the high prevalence of coronary artery disease in heart transplant recipients, currently used noninvasive tests as well as invasive tests are highly unreliable in predicting prognosis. We sought to test the hypothesis that the abnormalities induced by dobutamine stress echocardiography (DSE) may be of prognostic value in predicting acute cardiac events and mortality in heart transplant patients. We prospectively studied 86 survivors of orthotopic heart transplantation and followed them for a mean period of 2 years after the DSE. The patients' median age was 51 +/- 10 years, and mean duration since transplant was 57.7 +/- 29 months (range, 3 to 120 months, mean +/- SD). DSE was performed by a standard protocol (dobutamine 5, 10, 20, 30, and 40 micrograms.kg-1.min-1 at 5-minute stages). DSE was defined as positive for development of new or worsening regional wall motion abnormality or failure of augmentation. Nine patients were excluded from analysis (5 because of acute allograft rejection and 4 because of poor acoustic window). Thus, data from 77 patients were analyzed. Fifty-seven of 77 (74%) had positive DSE. After 24 months of follow-up, 19 of 57 patients with abnormal DSE (33%) experienced 22 major cardiac events. In contrast, no event occurred in patients with normal DSE. Of the 19 with cardiac events, there were 7 episodes of heart failure (including 3 deaths), 4 had unstable angina, and 5 died of cardiac causes. Three patients had myocardial infarction, and 3 others died of noncardiac causes. Among the variables examined, the baseline left ventricular ejection fraction was lower (44 +/- 3.8 versus 51 +/- 1.4) and peak wall motion score index was higher (2.01 +/- 0.4 versus 1.44 +/- 0.4) in the patients group with cardiac events than in those without events. These results suggest that DSE has significant value in predicting prognosis in post-heart transplant patients. Further studies are needed to define the role of DSE as a routine test for predicting prognosis in cardiac transplant recipients.