Iodine-123 metaiodobenzylguanidine imaging can predict future cardiac events in Japanese patients with Parkinson’s disease

Abstract

Iodine-123 metaiodobenzylguanidine (123I-MIBG) myocardial scintigraphy provides useful diagnostic information in differentiating Parkinson's disease (PD) from other neurological diseases. Moreover, a number of studies have reported that 123I-MIBG imaging provides powerful diagnostic and prognostic information in congestive heart failure (HF) patients. The aim of the present study was to investigate the cardiovascular predictive value of cardiac 123I-MIBG imaging in patients with PD. Seventy-eight patients with PD were retrospectively studied. All patients underwent 123I-MIBG imaging at 30 min (early) and 240 min (delayed) after the tracer injection, and clinical parameters were also investigated. During a mean follow-up of 27 ± 12 months, 5 patients required hospitalization for HF. There were no occurrences of myocardial infarction, fatal arrhythmia or sudden death. There was no significant coronary artery stenosis, significant valvular heart disease, or cardiomyopathy in the HF patients. The left ventricular ejection fraction (LVEF) was normal in the HF patients. (123)I-MIBG delayed heart to mediastinal ratio (delayed H/M) was lower and washout rate (WR) was higher in HF patients than non-HF patients (1.62 ± 0.21 vs. 1.34 ± 0.08, p = 0.019; 31.9 ± 5.5 vs. 38.2 ± 3.3, p = 0.005, respectively). Both WR and delayed H/M did not correlate with Hoehn and Yahr stage. The WR showed a weak negative correlation with delayed H/M (R = -0.357, p < 0.001) upon simple linear regression analysis. A multivariate Cox regression analysis revealed that WR and delayed H/M were independently associated with HF (p = 0.014, p = 0.029, respectively). Kaplan-Meier analysis revealed that patients with abnormal WR (> 37%) and delayed H/M (< 1.48) had a higher incidence of HF than those with normal WR and delayed H/M (p = 0.014, p = 0.04, respectively). WR showed stronger predictive power than delayed H/M in Kaplan-Meier analysis. WR has more useful cardiovascular predictive value than delayed H/M in Japanese patients with PD. Further studies are needed to clarify the significance of abnormal MIBG uptake in PD patients.