Reduced cardiac 123I-MIBG uptake reflects cardiac sympathetic dysfunction in Lewy body disease

Objective: To examine the relation between the results of cardiac 123 I-meta-iodobenzylguanidine (MIBG) scintigraphy and cardiovascular autonomic function in Lewy body disease (LBD). Methods: The subjects were 66 patients with LBD, 44 of whom had Parkinson disease (PD), 10 PD with dementia (PDD), and 12 dementia with Lewy bodies (DLB); 20 age-matched healthy subjects were studied as controls. Cardiovascular autonomic function was evaluated on the basis of cardiac 123 I-MIBG uptake, cardiovascular autonomic response on the Valsalva maneuver (VM), and systolic blood pressure (SBP) response on head-up tilt table (HUT) testing. Results: Patients with LBD had reduced cardiac 123 I-MIBG uptake, cardiovascular autonomic response on the VM, and SBP response on HUT testing as compared with controls. Cardiac 123 I-MIBG uptake and cardiovascular autonomic function in PDD and DLB were severely impaired as compared with those in PD. Cardiac 123 I-MIBG uptake in LDB was not significantly related to vasomotor sympathetic function, baroreceptor reflex gain, cardiac parasympathetic function, or the changes in SBP on HUT testing. Cardiac 123 I-MIBG uptake was, however, significantly related to the blood pressure overshoot in phase IV of the VM. Conclusion: Cardiac 123 I-meta-iodobenzylguanidine uptake clinically reflects cardiac sympathetic dysfunction in Lewy body disease. GLOSSARY: BRS = baroreceptor reflex sensitivity; DLB = dementia with Lewy bodies; H/M ratio = the ratio of the average pixel count in the heart to that in the mediastinum; HUT = head-up tilt table test; LBD = Lewy body disease; MIBG = 123 I-meta-iodobenzylguanidine; MMSE = Mini-Mental State Examination; PD = Parkinson disease; PDD = Parkinson disease with dementia; phase II E = systolic blood pressure decreases in early phase II; phase II L = systolic blood pressure increases in late phase II; PRT = pressure recovery time; VM = Valsalva maneuver; ROI = region of interest; SBP = systolic blood pressure; TH = tyrosine hydroxylase.