Significant correlation between renal 123 I-metaiodobenzylguanidine scintigraphy and muscle sympathetic nerve activity in patients with primary hypertension

Iodine-123 metaiodobenzylguanidine (123i-mibg) scintigraphy is used as a noninvasive imaging method for assessing cardiac sympathetic nerve activity. we tested the hypothesis that renal 123i-mibg imaging is correlated with muscle sympathetic nerve activity (msna) in patients with primary hypertension. thirty-one consecutive patients with primary hypertension were included. multiunit msna was recorded from the peroneal nerve to evaluate direct efferent sympathetic nerve activity. planar renal and cardiac 123i-mibg images were acquired. early and delayed kidney-to-mediastinum ratio (k/m), early and delayed heart-to-mediastinum ratio (h/m), and washout rates (wr) were calculated. in 27 of 31 patients, blood pressure was controlled on antihypertensive medication. mean systolic and diastolic blood pressures were 118 ± 18 and 67 ± 15 mmhg, respectively. although early and late k/m and h/m were not significantly correlated with msna, both cardiac and average renal wr were significantly correlated with msna (r = 0.45, p = .0035 and r = 0.68, p < .001, respectively). right and left renal wr were similarly correlated with msna. renal wr was significantly higher than cardiac wr (43.2% vs 25.8%, p < .001) in these patients with hypertension. renal 123i-mibg wr was significantly associated with multiunit msna. renal 123i-mibg imaging offers a noninvasive clinical methodology for assessing renal sympathetic nerve function.