Abstract 14513: Diastolic Wall Strain: A Simple Marker of Abnormal Cardiac Mechanics

Abstract

Introduction: According to linear elastic theory, diastolic left ventricular (LV) stiffness can be estimated by calculating diastolic wall strain (DWS), defined using posterior wall thickness (PWT) measurements from standard echo (DWS = [PWTs-PWTd]/PWTs). Recently, reduced DWS (=increased diastolic stiffness) was found to be associated with adverse cardiac remodeling and poor outcomes in patients with heart failure (HF) and preserved EF. However, whether DWS is associated with abnormal cardiac mechanics (reduced systolic strains and diastolic tissue velocities) is unknown. We hypothesized that reduced DWS is independently associated with abnormal cardiac mechanics.

Methods: We performed speckle-tracking analysis in the HyperGEN study (N=1426). Global longitudinal, circumferential, and radial strain (GLS, GCS, and GRS, respectively), and early diastolic (e’) tissue velocities were measured. We used linear mixed-effects modelling (to account for relatedness among subjects) to determine whether DWS is independently associated with GLS, GCS, GRS, and e’.

Results: The mean age was 55±12 years, 58% were female, 35% were black, 73% were hypertensive, 50% were obese, 15% were diabetic, and 94% had normal EF (>50%). Mean DWS 0.36±0.06. DWS decreased with increasing comorbidity burden (β-coefficient -0.013 [95% CI -0.015, -0.011]; P<0.0001). DWS was significantly associated with each index of cardiac mechanics on univariate analysis (R=0.30, 0.20, 0.15, and 0.26 for GLS, GCS, GRS, and e’, respectively; P<0.0001 for all associations). These findings persisted after adjustment for multiple potential confounders, including age, sex, center, image quality, systolic BP, wall motion abnormalities, LV mass index, and EF (P<0.0001 each index of cardiac mechanics). For example, for every standard deviation decrease in DWS, absolute GLS decreased by 0.64% (95% CI 0.44, 0.83%, P<0.0001). DWS was also independently associated with E/e’ ratio, global EF, and LV mass index (P<0.0001 for all associations).

Conclusions: DWS, a simple parameter that can be calculated from any 2D echo, is closely associated with multiple indices of cardiac mechanics. These findings may explain the association between reduced DWS and adverse outcomes in HF with preserved EF.