Abnormal myocardial uptake and clearance of 123I-labeled metaiodobenzylguanidine in patients with chronic renal failure and autonomic dysfunction.

BACKGROUND: Patients with chronic renal failure were evaluated with 123I-labeled metaiodobenzylguanidine (MIBG) myocardial scintigraphy to investigate the relationship between abnormal findings on MIBG scintigrams and autonomic dysfunction. METHODS AND
RESULTS: Eleven control subjects and 20 patients with chronic renal failure (CRF) (serum creatinine level > 8 mg/dl) were evaluated by MIBG myocardial scintigraphy and power spectral analysis (PSA) of the R-R fluctuations of the electrocardiogram. Subjects with CRF were divided into two groups: without (CRF1; nine patients) or with (CRF2; 11 patients) autonomic neuropathy. From MIBG images, the heart/mediastinum mean count rate, defect score, which was scored visually, and clearance rate were calculated. Percent low-frequency power and high-frequency power were obtained from PSA. MIBG scintigrams showed decreased heart/mediastinum mean count rate, a high defect score in both initial and delayed images, and rapid clearance rate in the CRF2 group. PSA showed an abnormally low percent low-frequency power and high-frequency power in the CRF2 group. In addition, there was a weak but significant inverse correlation between percent low-frequency power and defect score.
CONCLUSION: Alterations in MIBG scintigrams are seen in patients with autonomic dysfunction in CRF and may be useful for evaluating cardiac sympathetic dysfunction in those patients.