Usefulness of the pulmonary venous flow waveform for assessing left atrial stiffness

Abstract

Purpose: This study investigated the novel non-invasive left atrial (LA) stiffness parameter using pulmonary venous (PV) flow measurements and the clinical usefulness of the novel LA stiffness parameter.

Methods: We retrospectively analyzed 237 patients who underwent right heart catheterization and echocardiography less than one week apart. From the pulmonary artery wedge pressure waveform, the difference between x-descent and v-wave (ΔP) was measured. Using the echocardiographic biplane method of disks, the difference between LA maximum volume and that just before atrial contraction (ΔV_MOD) was calculated, and the ΔP/ΔV_MOD was calculated as a standard LA stiffness index. From the PV flow waveform, the peak systolic velocity (S), peak diastolic velocity (D), and minimum velocity between them (R) were measured, and S/D, S/R, and D/R were calculated. From the speckle tracking echocardiography-derived time-LA volume curve, the difference between LA maximum volume and that just before atrial contraction (ΔV_STE) was measured. Each patient's prognosis was investigated until three years after echocardiography.

Results: Among the PV flow parameters, D/R was significantly correlated with ΔP (r = 0.62), and the correlation coefficient exceeded that between S/D and ΔP (r = - 0.39) or S/R and ΔP (r = 0.14). The [D/R]/ΔV_STE was significantly correlated with ΔP/ΔV_MOD (r = 0.61). During the follow-up, 37 (17%) composite endpoints occurred. Kaplan-Meier analysis showed that patients with [D/R]/ΔV_STE greater than 0.13 /mL were at higher risk of cardiac events.

Conclusion: The [D/R]/ΔV_STE was useful for assessing LA stiffness non-invasively and might be valuable in the prognostic evaluation of patients with cardiac diseases.

Keywords: Echocardiography; Left atrial stiffness; Left atrial v-wave; Pulmonary venous flow; Speckle tracking echocardiography.