Echocardiographic left atrial stiffness index predicts high left ventricular filling pressures in patients with acute heart failure: an observational study.

Background: In acute heart failure (AHF) patients, non-invasive estimation of left ventricular filling pressures (LVFPs) appears crucial to guide management. Although poorly investigated, left atrial (LA) mechanics play a pivotal role in this setting. This report sought to assess the correlation of echocardiographic LA stiffness index with invasive LVFPs and its diagnostic accuracy as compared to other parameters used in clinical practice.

Methods: In this observational, prospective study, 104 patients with suspected acute coronary syndrome and signs/symptoms of AHF were enrolled. Available invasive estimation of LVFPs was required. Comprehensive echocardiography was performed for all patients, including LA reservoir strain (LARS). LA stiffness index was derived by speckle-tracking analysis and Tissue Doppler imaging as early diastolic transmitral inflow velocity/mitral annulus early diastolic velocity [E/e']/LARS.

Results: Invasively measured LVFPs showed a strong correlation with LA stiffness index (Spearman ρ = 0.773, p < 0.0001), as well as with LARS and E/e'. Receiver operating characteristic (ROC) curve analysis was used to demonstrate better accuracy performed by LA stiffness index than average E/e', LA volume or LARS alone, in predicting high LVFPs. Guideline-recommended assessment of diastolic function was finally compared to LARS and LA stiffness index performances in an independent population group; we were hence able to obtain a LA stiffness threshold of 0.48 with a positive predictive value of 91.7% and a negative predictive value of 88.9% in identifying patients with high LVFPs.

Conclusions: For the first time, diagnostic performance of LA stiffness index has been investigated in a heterogeneous AHF population, providing correlations with invasively measured LVFPs and comparisons with established diastolic function metrics.