title: Risk stratification assessed by combined lung and heart iodine-123 metaiodobenzylguanidine uptake in patients with idiopathic dilated cardiomyopathy.
abstract: Iodine-123 metaiodobenzylguanidine (123I-MIBG) has been used to assess myocardial sympathetic nervous activity and severity of heart failure. (123)I-MIBG is also used as a potential marker of pulmonary endothelial cell function and may be related to pulmonary hypertension. Thus, we hypothesized that combined assessment of lung and heart 123I-MIBG kinetics predicts future clinical outcome more accurately than myocardial evaluation alone in patients with chronic heart failure. To test this hypothesis, we examined 123I-MIBG scintigrams in 62 consecutive patients with idiopathic dilated cardiomyopathy. Anterior planar images were obtained 15 minutes and 3 hours after 123I-MIBG injection. Cardiac and pulmonary 123I-MIBG activities were quantified as heart-to-mediastinum activity ratio and lung-to-mediastinum activity ratio. We introduced lung-to-heart activity ratio as the new 123I-MIBG parameter including myocardial sympathetic nerve activity and pulmonary endothelial cell function. Delayed lung-to-heart ratio was correlated with pulmonary vascular resistance (r = 0.48, p <0.0001), disease duration (r = 0.49, p <0.0001), and number of heart failure episodes (r = 0.55, p <0.0001). During a mean follow-up of 25 months, 15 patients had a cardiac event. Area under receiver operating characteristic curves for prediction of the event was greatest in delayed lung-to-heart ratio (lung to heart 0.92, heart to mediastinum 0.83, lung to mediastinum 0.80). In multivariate analysis, the lung-to-heart ratio (hazard ratio 2.76/0.1 increase, p = 0.002) was selected as an independent predictor for a future cardiac event. In conclusion, the combined assessment of lung and heart 123I-MIBG uptake may help to predict future clinical outcome for patients with idiopathic dilated cardiomyopathy more accurately than myocardial evaluation alone.
authors.affiliation: Division of Cardiovascular Medicine, Matsumoto, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kamiyoshi
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Yazaki
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Urushibata
authors.forename: Tomonori
authors.initials: T
authors.lastname: Koizumu
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kasai
authors.forename: Atsushi
authors.initials: A
authors.lastname: Izawa
authors.forename: Osamu
authors.initials: O
authors.lastname: Kinoshita
authors.forename: Minoru
authors.initials: M
authors.lastname: Hongo
authors.forename: Uichi
authors.initials: U
authors.lastname: Ikeda
mesh_terms: D019797:3-Iodobenzylguanidine / Q000008:administration & dosage / Q000493:pharmacokinetics; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000401:mortality; D005260:Female; D005500:Follow-Up Studies; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D007275:Injections, Intravenous; D007457:Iodine Radioisotopes / Q000008:administration & dosage / Q000493:pharmacokinetics; D007564:Japan / Q000453:epidemiology; D008168:Lung / Q000000981:diagnostic imaging* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000493:pharmacokinetics; D018570:Risk Assessment / Q000379:methods; D015996:Survival Rate / Q000639:trends; D013997:Time Factors
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine