Abstract 21325: Is Retention of the Presynaptic Sympathetic Nerve Function Probe, [11C] Hydroxyephedrine, Related to Myocardial Blood Flow in Non-Ischemic Cardiomyopathy?
Introduction: Impaired cardiac presynaptic sympathetic nervous (SN) function measured using meta-iodobenzylguanidine (MIBG) or [11C] hydroxyephedrine (HED) PET has been identified as a prognostic indicator in patients with heart failure (HF). Reperfusion studies in animals have suggested that HED retention is dependent on perfusion. However, it is unclear whether the same principle applies to patients with non-ischemic cardiomyopathy (NICM). We sought to determine whether there is a relationship between [11C] hydroxyephedrine (HED) retention and resting myocardial blood flow (MBF) - measured with [11C] acetate kinetics, which would have implications for HED retention as a parameter for measuring SN function.
Methods: We prospectively evaluated 18 HF patients with chronic stable NICM (left ventricular ejection fraction (LVEF) ≤ 40% and New York Heart Association (NYHA) class ≥ II). Global myocardial presynaptic SN function was quantified using HED PET uptake and retention. Rest MBF was assessed with [11C] acetate PET time-activity data using a one-compartment model.
Results: For the 18 patients [mean age 61 yrs (±11), 55% male, 83% NYHA class II), mean LVEF was 32% (±6) and 71% had obstructive sleep apnea. Global HED retention was related to LVEF (r=0.41, p=0.09) and also significantly correlated with [11C] acetate MBF at rest (r=0.85 p=<.0001) (figure). After correction for MBF (HED/MBF) the relation with LVEF was no longer apparent.
Conclusions: Myocardial retention of HED is significantly dependent on MBF in patients with NICM. This data underscores the importance of parallel MBF measurements and correction of HED retention for flow to ensure accurate interpretation of neuronal imaging PET studies in HF populations. This relationship could impact the prognostic value of presynaptic SN function probes and requires further study.
- © 2010 by American Heart Association, Inc.