Abstract 14666: Prediction of Mode of Death in Patients with Chronic Heart Failure by Cardiac I-123 Metaiodobenzylguanidine Imaging and 6- Minute Walk Test: A Long-Term Follow-Up Comparative Study

Abstract

Background: The 6-minute walk test (6MWT) and cardiac I-123 metaiodobenzylguanidine (MIBG) imaging provide prognostic information in patients with chronic heart failure (CHF). Prediction of mode of death (sudden cardiac death (SCD) and pump failure death (PFD)) may facilitate decisions about specific medications or devices. However, no information is available on the prognostic significance of the combination of 6MWT and cardiac MIBG imaging in CHF patients, relating to mode of death in CHF patients.

Methods: We prospectively studied 112 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 7.3±4.0 (0.1-15.3) years, 11 of 109 patients had PFD and 23 patients had SCD. As for PFD, 6MWT distance (p=0.03) and cardiac MIBG WR (p=0.02) were significantly independently associated with the poor outcome at multivariate Cox analysis. Patients with abnormal 6MWT distance and abnormal WR had a significantly higher risk of PFD than those with either abnormal 6MWT distance or abnormal WR and those with normal 6MWT distance and normal WR (29% vs 12% vs 2%, respectively, p=0.0003). Hazard ratio (HR) for PFD of abnormal 6MWT distance and abnormal WR (29.3 (95%CI 3.2 to 267.5)) was 3.5-fold of HR of either abnormal 6MWT distance or abnormal WR (8.1 (95%CI 0.97 to 68.1)). On the other hand, as for SCD, only cardiac MIBG WR was independently associated with the poor outcome at multivariate Cox analysis. Patients with abnormal WR had higher risk of SCD than those with normal WR (HR 3.8 (95%CI 1.5 to 9.7), 29% vs 12%, p=0.0028).

Conclusion: The combination of 6MWT and cardiac MIBG imaging would be useful for the prediction of pump failure death in CHF patients, while only cardiac MIBG imaging had the predictive value for sudden cardiac death.