Abstract 15465: Influence of Ejection Fraction on the Prognostic Value of Sympathetic Innervation Imaging with Iodine-123 Meta-iodobenzylguanidine (123I-mIBG) in Heart Failure: An Echocardiography Sub-analysis from the ADMIRE-HF Trial
Background: In systolic heart failure (HF), abnormal myocardial sympathetic innervation imaging by 123I-mIBG and reduced LV ejection fraction (EF) are both associated with increased risk of cardiovascular events, but the interaction between these two measures has not been investigated in detail.
Methods: The prospective multicenter ADMIRE-HF study enrolled 961 subjects with class II/III HF and site-determined EF≤35% to evaluate the prognostic value of abnormal 123I-mIBG imaging, predefined as 4-hour heart-to-mediastinum ratio (H/M ratio) <1.6, for risk of death, HF progression, or arrhythmic event. Median follow-up was 17 months. Baseline echocardiograms acquired for the study were independently analyzed by a core laboratory in a blinded fashion. We grouped subjects based on core lab EF and employed multivariable Cox proportional hazard models to determine the risk associated with low H/M ratio among each EF group and to test for EF-H/M ratio interaction.
Results: Core lab determined EF was available in 901 subjects and ranged from 20–58% (mean EF 34±7%). Core lab EF was >35% in 384 subjects. H/M ratio<1.6 was associated with an increased risk at all levels of EF (figure). Comparing subjects with EF<35% and ≥35%, there was no evidence of effect modification of EF on risk associated with low H/M ratio: composite death/arrhythmic event/HF progression HR 1.80 (95% CI 1.01–3.21) with EF<35% versus 2.23 (95% CI 1.03–4.84) with EF≥35%, interaction p=0.76; death/arrhythmic event HR 2.38 (95% CI 1.03–5.53) versus 4.46 (1.03–19.3), interaction p=0.55; death/HF progression HR 1.61 (95% CI 0.90–2.89) versus 2.25 (95% CI 0.99–5.12), interaction p=0.91.
Conclusions: Myocardial sympathetic innervation imaging with 123I-mIBG has prognostic value across a broad spectrum of EF, suggesting that further studies may be warranted to test the prognostic value of 123I-mIBG imaging in patients with HF and preserved EF.
- © 2010 by American Heart Association, Inc.