Correlation between USCOM-derived haemodynamic variables and severity of chronic heart failure [Abstract]

Background: Ultrasonic Cardiac Output Monitor (USCOM)-derived inotropy has been shown to discriminate patients with New York Heart Association (NYHA) stage IV from healthy controls. This study aims to investigate whether inotropy and other haemodynamic variables correlate with NYHA class and ejection fraction (EF). Methods: Ethical approval was obtained to conduct a prospective, single-centre, observational study of patients presenting with heart failure symptoms to the echocardiography clinic at Prince of Wales hospital. The echocardiography and USCOM assessments were conducted by separate trained technicians who were blind to results from each other. The primary outcome was difference in mean inotropy between NYHA classes I, II, III, and IV. Secondary outcome was correlation between USCOM hemodynamic parameters and left ventricular ejection fraction (LVEF). (Clinical trial no. NCT02289508) Results: Between June 2014 and January 2015, a convenience sample of 117 subjects were enrolled (NYHA Class I, n=28 (24%); Class II, n=58 (50%); Class III, n=22 (19%); Class IV n=7 (6%)). Differences between stroke volume index (SVI) and DO2 were found to be significant across NYHA classes (p<0.05). Differences in inotropy, cardiac index (CI) and systemic vascular resistance index (SVRI) were not significant. USCOM-SVI showed moderate correlation with Echo-LVEF (r=0.41; p<0.01). USCOM-SVRI (r=0.30, p<0.01), USCOM-CI (r=.29, p<0.01), and USCOM-inotropy (r=0.27, p<0.01) also showed weak to moderate correlation with LVEF. Conclusion: The preliminary finding of this study shows that the USCOM-SVI and USCOM-DO2 correlated with NYHA stages of heart failure, and USCOM-SVI correlated with LVEF. The preliminary finding of this study suggests a possible role of USCOM to augment bedside assessment of patients with nonspecific heart failure presentation.