Abstract 10858: Significant Association Between Washout Ratio of Renal 123i-metaiodobenzylguanidine and Muscle Sympathetic Nerve Activity in Patients With Hypertension
Background: Simplicity HTN-3 trial showed the negative result for renal denervation (RDN) in patient with resistant hypertension. One of limitations was that no appreciate evaluation of renal sympathetic nerve activity (RSNA) was applied before and after RDN. 123I-MIBG has been used to assess the cardiac sympathetic nerve activity. However, it remains unclear whether 123I-MIBG in kidney would reflect sympathetic nerve activity. In this study, we investigated the relationship renal 123I- MIBG and muscle sympathetic nerve activity (MSNA).
Methods: 31 hypertensive patients were included in this study. MSNA was recorded from the peroneal nerve to evaluate direct sympathetic nerve activity to peripheral vascular bed. Images of 123I-MIBG were taken using the low-medium-energy general purpose collimator. An 111MBq dose of 123I-MIBG was injected intravenously at rest for the MIBG study. 123I-MIBG planar and SPECT studies were performed at 20min (early) and 3hr (delayed) after injection. In the planar study, a region of interest (ROI) was set over the heart and a rectangular ROI on the upper third of the mediastium and kidney cortex. The early and delayed heart-to-mediastinum average count ratios (H/M) and kidney-to-mediastinum average count ratios (K/M) were calculated. Washout rate (WR) of heart and kidney were also calculated.
Results: Average systolic and diastolic blood pressure was 118±18/67±15 mmHg. Average estimated glomerular filtration rate was 71.5±22.4 ml/min/1.73m2 that was not related to renal 123I-MIBG. As expected, MSNA had significant negative relationship with delayed H/M in cardiac 123I-MIBG image (r=-0.37, p<0.01) and positive relationship with WR of cardiac 123I-MIBG (r=0.45, p<0.01). With regard to kidney, WR of 123I-MIBG of each left and right renal MIBG showed a significant correlation with MSNA (right kidney: r=0.56, p<0.01, left kidney: r=0.60, p<0.01, respectively), but not with early and delayed K/M in renal 123I-MIBG.
Conclusions: Our study showed that WR of renal 123I-MIBG was associated with MSNA, indicating that WR of renal 123I-MIBG might reflect RSNA. These results suggest that renal 123I-MIBG might be available to assess sympathetic nerve activity as well as MSNA.
Author Disclosures: Y. Okabe: None. H. Murai: None. S. usui: None. H. Furusho: None. M. Takamura: None.
- © 2015 by American Heart Association, Inc.