Correlation between energy loss index and B-type natriuretic peptide: a vector flow mapping study.

Background: Vector Flow Mapping (VFM) and Energy Loss (EL) evaluation are emerging echocardiographic techniques that offer detailed insights into cardiac function. This study aimed to explore the relationship between EL parameters and B-type natriuretic peptide (BNP) levels, a well-established marker of heart failure severity.

Methods: Our study prospectively enrolled 62 patients experiencing shortness of breath and suspected heart failure, who underwent echocardiography and had BNP levels measured between January 2018 and August 2020. Patients were stratified based on BNP levels, and their clinical and echocardiographic characteristics were evaluated. Univariate and multivariate regression analyses were performed to assess the correlation between BNP levels and various echocardiographic variables, including VFM parameters.

Results: Patients were stratified into two groups based on their BNP levels: BNP < 200 pg/ml (n = 53) and BNP ≥ 200 pg/ml (n = 9). Patients with BNP ≥ 200 pg/ml presented significantly different clinical and echocardiographic characteristics, such as older age, larger left ventricular mass and volume indices, higher pulmonary artery systolic pressure, higher E/e' ratio, and larger EL parameters. Multivariate regression analysis demonstrated the E/e' ratio and ELA (EL during Atrial contraction phase/A wave ratio as significant determinants of logBNP. Receiver operating characteristic curve analysis showed ELA/A > 36.0 J/m² as a significant predictor of high BNP with 89% sensitivity and 85% specificity. ELA/A demonstrated an incremental diagnostic value over elevated left atrial pressure for predicting high BNP (C statistic = 0.98 vs 0.74, P = 0.006).

Conclusion: This study provides novel insights into the potential utility of EL parameters as auxiliary indicators of cardiac load, thereby enhancing our understanding of heart failure.