Physiologic variability: prevalence and extent of changes in echocardiographic parameters in different hemodynamic situations – Results from AAVEP

L. Lutz (Würzburg)¹, D. D. Pelin (Würzburg)², M. Chen (Würzburg)², G. Schummers (Unterschleißheim)³, N. Gellermann (Würzburg)¹, S. Frantz (Würzburg)⁴, G. Gelbrich (Würzburg)⁵, M. Schreckenberg (Unterschleißheim)³, S. Störk (Würzburg)², C. Morbach (Würzburg)^6
1Universitätsklinikum Würzburg Deutsches Zentrum für Herzinsuffizienz Würzburg, Deutschland; ²Universitätsklinikum Würzburg Deutsches Zentrum für Herzinsuffizienz/DZHI Würzburg, Deutschland; ³TomTec Imaging Systems GmbH Clinical Innovations Unterschleißheim, Deutschland; ⁴Universitätsklinikum Würzburg Medizinische Klinik und Poliklinik I Würzburg, Deutschland; ⁵Universitätsklinikum Würzburg Institut für Klinische Epidemiologie und Biometrie Würzburg, Deutschland; ⁶Universitätsklinikum Würzburg Medizinische Klinik I, Kardiologie Würzburg, Deutschland

Background: Echocardiography (echo) is broadly implemented in routine care to monitor patients with progressive heart disease (e.g. cardiac amyloidosis) as well as patients undergoing potentially cardiotoxic therapy (e.g. chemotherapy for malignoma). The threshold to identify a deterioration of myocardial function is high (e.g. reduction in left ventricular ejection fraction (LVEF) of 10% or relative reduction of global longitudinal strain (GLS) > 15%) due to observer but also physiological variability.
Aims: to quantify the change under different hemodynamic conditions for several echocardiographic parameters in order to identify robust parameters qualifying best for patient monitoring.
Methods: AAVEP is a cross-sectional study including healthy volunteers who underwent transthoracic echocardiography at rest as well as under stress: passive leg lifting, mental arithmetic test and sustained handgrip exercise, respectively, with a 5min resting period in-between the tests. We applied continuous heart rate monitoring as well as blood pressure measurement before and immediately after each stress test. To minimize observer variability, we applied automated reading with manual adjustments, if necessary, using the Ultrasound Workspace^® (TOMTEC IMAGING SYSTEMS). Correlated data obtained from multiple measurements under induced hemodynamic states and adjusted for age and sex were compared to baseline using generalized estimating equation.
Results: We enrolled n=20 Caucasian participants aged 20-78 years with a mean age of 44.3 years and stratified for sex (1:1). All participants showed age-appropriately normal cardiac dimensions and function at rest. Participants showed an increase in heart rate in each induced hemodynamic status as well as an increase in systolic blood pressure during handgrip exercise. The LVEF 2D showed stable results through all hemodynamic states. Conversely, LVEF 4D revealed significant changes during induced stress, respectively, while the GLS 4D exhibited a significant increase during the mental arithmetic test (table).
Conclusion: We found a significant change in hemodynamic conditions in each of the stress scenarios, which translated into significant changes in several echocardiographic parameters. GLS and LVEF from 3D volumes were more sensitive to these hemodynamically induced changes than 2D LVEF.  Our findings highlight the importance of equal hemodynamic conditions in serial echocardiography as well as the need for robust echocardiography parameters.