Abstract 15300: Cardiac I-123 Metaiodobenzylguanidine Imaging Improves the Prognostic Power of 6-Minute Walk Test in Patients With Chronic Heart Failure: a Long-Term Follow-Up Study
Background: The 6-minute walk test (6MWT) is an established prognostic tool in patients with chronic heart failure (CHF). In addition, cardiac I-123 metaiodobenzylguanidine (MIBG) imaging also provides prognostic information in CHF patients. However, the long-term predictive value of combining the 6MWT and cardiac MIBG imaging in CHF patients has not been elucidated. We prospectively investigated whether cardiac MIBG imaging provides additional prognostic value to the 6MWT in CHF patients.
Methods: We studied 109 CHF outpatients with LV ejection fraction (LVEF) <40% (29±8%). The 6MWT was performed at the enrollment, and abnormal 6MWT distance was defined as less than 300m. Cardiac MIBG washout rate (WR) was calculated from the chest anterior view images obtained at 20 and 200 min after isotope injection. Abnormal WR was defined as WR>27%.
Results: With a mean follow-up of 6.1±4.4 (0.1-15.3) years, 49 of 109 patients had poor outcome (cardiac death or hospitalization for heart failure). At multivariate Cox analysis, WR (p=0.001) and 6MWT distance (p=0.04) were significantly independently associated with poor outcome. Patients with abnormal WR and abnormal 6MWT distance had a significantly higher risk of poor outcome than those with either abnormal WR or abnormal 6MWT distance and those with normal WR and normal 6MWT distance (86% vs 56% vs 21%, respectively, p<0.0001). Hazard ratio (HR) of abnormal WR and abnormal 6MWT distance (8.46 (95%CI 3.61 to 19.84)) was two-fold of HR of either abnormal WR or abnormal 6MWT distance (4.06 (95%CI 1.95 to 8.44)).<bold>
Conclusion: Cardiac MIBG WR provides additional prognostic information to the 6MWT in CHF patients.
- © 2011 by American Heart Association, Inc.