Combined Assessment of Baroreflex Sensitivity With Iodine 123 Metaiodobenzylguanidine Scintigraphic Findings Strengthens the Power of Predictive Value for Cerebral and Cardiovascular Events in Type 2 Diabetic Patients

Abstract

Background: We previously reported that baroreflex sensitivity (BRS) or cardiac iodine 123 metaiodobenzylguanidine (¹²³I-MIBG) scintigraphic findings can predict cardiovascular prognosis in type 2 diabetic patients. We therefore tested the hypothesis that the combination of BRS and ¹²³I-MIBG scintigraphic findings could strengthen the predictive power for major adverse cerebral and cardiovascular events (MACCE). Methods and Results: From 1998, we have evaluated both BRS and ¹²³I-MIBG scintigraphy in 165 type 2 diabetic patients (77 females, 88 males, mean age 59±12 years). Based on the ROC curves, depressed BRS was defined as <5.63mmHg/s, and enhanced washout ratio (WR) was defined as ≥41.4%. Each patient was divided into 3 groups based on the “BRS-MIBG combination score” as follows: 0, patients having both preserved BRS and preserved WR; 1, patients having either depressed BRS or enhanced WR; 2, patients having both depressed BRS and enhanced WR. During the mean of 4.7±2.7 years of follow-up, 19 patients developed MACCE. The MACCE-free ratio was significantly higher in the lower BRS-MIBG combination score group (log-rank 16.41, P=0.0003). Cox proportional hazards regression analysis revealed that BRS-MIBG combination score was independently associated with the incidence of MACCE (hazard ratio 4.06, P=0.0237). Conclusions: Our results suggest that combined assessment of the BRS and ¹²³I-MIBG scintigraphic findings is more useful for identifying the type 2 diabetic patients at high risk for MACCE.