Abstract 10593: Resting Energy Expenditure is an Important Factor to Predict Cardiac Mortality in Chronic Heart Failure

Abstract

Introduction: Parameters derived from cardiopulmonary exercise testing (CPET) with respiratory gas analyzer are important prognostic factors in patients with chronic heart failure (CHF). However, all patients with CHF cannot undergo CPET for reasons such as frailty and comorbidity. On the other hands, resting energy expenditure (REE) derived from respiratory gas analyzer can be easily measured in most patients with CHF, but clinical significance of this parameter had not been fully elucidated in patients with CHF. Aims: We aimed to determine the clinical importance including the prognostic impact of REE in patients with CHF. Methods: A total of 1185 consecutive CHF patients who underwent CPET were enrolled. REE was calculated by Weir's formula (3.941resting oxygen consumption (VO 2 )+1.106resting carbon dioxide production (VCO 2 )). The study population was divided into two groups according to median REE and we compered the clinical characteristics between two groups. Also, we examined the value of REE to predict cardiac mortality in CHF patients. Results: In all subjects, 966 were males, median age was 63 years. Median resting VO 2 was 236 ml/min, median resting VCO 2 was 222 ml/min and median REE was 1178 kcal/day. Patients with low REE (<1178 kcal/day) were older and had higher prevalence of female and anemia, lower body mass index (BMI), more impaired renal function, lower parameters of nutrition such as serum total protein and albumin, higher levels of plasma type-B natriuretic peptide, lower resting VO 2 , lower resting VCO 2 and lower peak VO 2 than those with high REE (>1178 kcal/day). But left ventricular ejection fraction was similar between two groups. Patients with low REE had significantly higher rates of cardiac death, all cause death and composite cardiac event (cardiac death and re-hospitalization due to worsening heart failure). Furthermore, REE was the independent predictor of cardiac death, all-cause death and composite cardiac events in the Cox proportional hazard analysis after adjusted cofounding variables including peak VO 2 . Conclusions: REE as well as peak VO 2 is important predictor of cardiac mortality in patients with CHF.