The Difference Between Calculated Functional Ejection Fraction by Using Cardio Ankle Vascular Index Examination and Measured Ejection Fraction by Using Transthoracic Echocardiography

These days some studies report that 40% to 50% of patient with heart failure have preserved ejection fraction and the pathogenesis of that may relate to the ratio of ventricular end‐systolic elastance (Ees) to effective arterial elastance (Ea). Ees/Ea is known to reflect not only ventricular mechanical performance but also energetic performance. Despite these useful features, we don't use it in clinical site because of need invasive technique to estimate it. Hayashi et al developed a framework to estimate Ees/Ea without measuring ventricular volume and pressure. We evaluated the difference between calculated functional ejection fraction (EFe =SV/(Ved‐V0), SV is stroke volume, Ved is end‐diastolic volume, V0 is left ventricle unstressed volume) using by Cardio Ankle Vascular Index (CAVI) examination and measured ejection fraction (EF) by using transthoracic echocardiography. First we confirmed that correlation between measured and calculated Ees/Ea by using Hayashi's original dog data. We used Newton's method to calculate equations. Second we applied this equation to CAVI examination data to calculate human EFe. Afterwards we made scatter diagram about calculated EFe and EF measured by echocardiography in 24 patients who examined CAVI and echocardiography within a period of July 2006 to June 2011 at the Hospital, Fukui University, Japan. The first analysis results showed a correlation coefficient of 0.78 (p < 0.0001, 95% confidence limits of 0.687 – 0.844).Then revised Ees/Ea was calculated by using an approximate equation(revised Ees/Ea=Ees/Ea×0.4301+0.2712). Final scatter diagram about human EF showed that patients have similar measured EF were not similar calculated EFe. There is possibility of calculate noninvasive human Ees/Ea, and it may correlate heart failure with preserved ejection fraction.