Cardiac Iodine-123 Metaiodobenzylguanidine (123I-MIBG) Scintigraphy Parameter Predicts Cardiac and Cerebrovascular Events in Type 2 Diabetic Patients Without Structural Heart Disease

Background: Cardiac iodine-123 metaiodobenzylguanidine (123I-MIBG) scintigraphy is an established method of assessment of cardiovascular sympathetic function. The aim of the present study was to investigate the long-term cardiovascular predictive value of cardiac 123I-MIBG scintigraphy parameters in Japanese type 2 diabetic patients without structural heart disease. Methods and Results: Cardiac 123I-MIBG scintigraphy in 108 patients with type 2 diabetes who did not have structural heart disease, was evaluated. The washout rate (WR) was considered enhanced if it was ≥40%. Accurate follow-up information for 4.6 years was obtained in 54 enhanced WR patients (27 male; mean age, 61±11 years) and in 54 sex- and age-matched preserved WR patients (27 male; mean age, 61±10 years). Major adverse cardiac and cerebrovascular events (MACCE) were investigated. During follow-up, 10 enhanced WR patients developed MACCE including cardiac death, coronary revascularization, stroke, and congestive heart failure, while MACCE occurred in only 3 male patients. The Kaplan-Meier curves indicated that enhanced WR patients had higher incidence of MACCE than those with preserved WR (P<0.05). Cox proportional hazards regression analysis showed that age and enhanced WR were independently associated with the incidence of MACCE (hazard ratio, 4.06; 95% confidence interval: 1.194-18.76, P=0.0237). Conclusions: Abnormal WR of cardiac 123I-MIBG scintigraphy at baseline has long-term cardiovascular predictive value in Japanese patients with type 2 diabetes without structural heart disease. (Circ J 2012; 76: 399-404)