Correlation of the E/E'-ratio to NT-BNP: echocardiographic subanalysis of the LIFE-Adult-Study

The E/E'-ratio is used as a surrogate parameter for the estimation of the left ventricular enddiastolic pressure. It is assumed that chronic systolic and diastolic heart failure is associated with E/E'-values of more than 15 or at least with intermediate values between 9 – 5. The aim of the present retrospective analysis of the epidemiological echocardiographic cohort of the LIFE-Adult study (Leipzig Research Centre for Civilization Diseases) was to evaluate the correlation of NT-BNP (N-terminales propeptid BNP) values to the E/E'-ratio by the assessment of left ventricular diastolic function in this cohort.

In 773 participants (pts) standardised transthoracic echocardiography was performed and in 748 pts NT-BNP was analysed. The E/E'-ratio was determined according to the international recommendations by measuring the maximum velocity of the early diastolic inflow by pulsed wave Doppler echocardiography and the basal septal maximum myocardial velocity by tissue Doppler echocardiography at early diastole. NT-BNP was determined using commercially available diagnostic tests. Pathological NT-BNP levels were assumed in the range > 222pg/ml.

Normal E/E'-ratios as well as normal NT-BNP levels were observed in 91% of all participants. In 1.4% of the pts elevated NT-BNP levels were found in the presence of normal E/E'-ratio. In contrast in 1.1% of the pts elevated E/E'-ratios were found in the presence of normal NT-BNP levels. Most of the pts with heart failure detected by NT-BNP vales > 222pg/ml also showed intermediate E/E'-ratios between 9 and 15 (42pts). In only 0.8% of the pts (5 pts) significantly elevated E/E'-ratios > 15 and pathological NT-BNP levels could be observed (see fig). Only 4 pts with elevated NT-BNP values showed left ventricular systolic dysfunction.

E/E'-ratio has to be verified to be suitable for the detection of heart failure patients. The present data show that E/E'-ratio of > 15 is not well correlated to increased NT-BNP levels.