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: Yuichi Kamiyoshi, Yoshikazu Yazaki, Kazutoshi Urushibata, Tomonori Koizumu, Hiroki Kasai, Atsushi Izawa, Osamu Kinoshita, Minoru Hongo, Uichi Ikeda
• Journal: The American journal of cardiology (Am J Cardiol) Vol. 101 Issue 10 Pg. 1482-6 (May 15 2008) ISSN: 0002-9149 [Print] United States
• PMID: 18471462 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Iodine Radioisotopes
• Radiopharmaceuticals
• 3-Iodobenzylguanidine

Topics

• 3-Iodobenzylguanidine (administration & dosage, pharmacokinetics)
• Cardiomyopathy, Dilated (diagnostic imaging, metabolism, mortality)
• Female
• Follow-Up Studies
• Heart (diagnostic imaging)
• Humans
• Injections, Intravenous
• Iodine Radioisotopes (administration & dosage, pharmacokinetics)
• Japan (epidemiology)
• Lung (diagnostic imaging, metabolism)
• Male
• Middle Aged
• Myocardium (metabolism)
• Prognosis
• Prospective Studies
• ROC Curve
• Radionuclide Imaging
• Radiopharmaceuticals (administration & dosage, pharmacokinetics)
• Risk Assessment (methods)
• Survival Rate (trends)
• Time Factors