E/e’ Does Not Consistently Track Left Atrial Pressure When Venous Return Is Altered in Individual Subjects

By James P. MacNamara, M.D., Advanced Echocardiography Fellow, and Satyam Sarma, M.D., Assistant Professor of Internal Medicine

The E/e’ ratio has become the foundation of echocardiographic assessment of left ventricular diastolic function. Many clinicians and researchers use E/e’ as a surrogate measurement of left ventricular filling pressure in patients with and without known cardiovascular disease. These conclusions are based primarily on cross-sectional data, and prior studies have raised concerns that E/e’ does not actually “measure” LV filling pressure.

The goal of our study, presented virtually at #AHA20, was to determine if E/e’ changed in parallel when LV filling pressure was altered experimentally in healthy, sedentary middle-aged adults. We used lower body negative pressure and rapid saline infusion to decrease and increase cardiac venous return, respectively. Using echocardiography and right heart catheterization, we measured E/e’ and pulmonary capillary wedge pressure (PCWP) simultaneously and performed a linear regression for each subject.

As a group, E/e’ was modestly associated with PCWP. Yet only 31% had a close correlation between E/e’ and PCWP. No subject had a 1:1 relationship between E/e’ and PCWP. Further, invasively measured LV compliance, LV relaxation, and baseline LV filling pressure did not predict whether a subject had a close relationship between E/e’ and PCWP. Our study highlights the limitations of using E/e’ as a measure of LV filling pressure, particularly in healthy adults. While E/e’ may be associated with PCWP in large groups of individuals, it is impossible for clinicians to know if E/e’ is useful in their individual patient. Therefore, we believe E/e’ may be a good marker of cardiac disease but should not be considered a “measurement” of LV filling pressure in clinical practice.