Prognostic value of 123I-metaiodobenzylguanidine in patients with various heart diseases

It has been reported that 123I-metaiodobenzylguanidine (MIBG) scintigraphy can predict the poor prognosis in patients with dilated cardiomyopathy (DCM). However, the prognostic significance of MIBG is still unknown in patients with other heart diseases. In this study, we compared the prognosis and MIBG findings in various heart diseases. Consecutive 565 patients undergoing MIBG scintigraphy were enrolled (392 men, 52±16 years). Indications were that 127 had ischemic heart disease (IHD), 120 DCM, 101 hypertrophic cardiomyopathy (HCM), 21 hypertensive heart disease (HHD), 58 volume-load valvular disease (VVD), 38 pressure-load valvular disease (PVD), and 101 ventricular tachycardia or fibrillation (VTF). Heart-to-mediastinum ratio (H/M) and washout rate (WR) of MIBG were evaluated. Cardiac events were defined as sudden cardiac death, heart failure, and acute ischemic event (follow-up, 22.7±17.0 months). A total of 106 cardiac events including 40 cardiac deaths occurred. Cox hazard model analysis showed that in the IHD, HCM, and DCM groups, H/M and WR were associated with cardiac death, but not in the HHD, PVD, VVD, or VTF groups. Only death and congestive heart failure (CHF) episodes were related to H/M and WR. On the other hand, fatal arrhythmia, myocardial infarction, or angina pectoris were not related to H/M and WR. The data indicated that WR or H/M may predict death and CHF but does not predict fatal arrhythmia or acute ischemic event. MIBG WR and H/M were associated with heart failure, sudden death, and cardiac death events, and were useful to predict the prognosis in DCM, HCM, and IHD. In contrast, fatal arrhythmia events were not associated with MIBG indices, and thus it does not appear to be useful in predicting cardiac events in patients with VTF. (author)