Abstract 18449: Mechanical Dispersion Improves Risk Stratification in Severe Aortic Stenosis Beyond Left Ventricular Ejection Fraction
Background: Left ventricular (LV) mechanical dispersion assessed with strain echocardiography reflects heterogeneity in systolic deformation and has been associated with ventricular arrhythmias and cardiac arrest in primary electrical and ischaemic heart disease. We hypothesized mechanical dispersion may predict occurrence of all-cause mortality in severe aortic stenosis (AS).
Methods: 424 patients (63.7 % men, 69±12 years) with severe AS (indexed aortic valve area 0.53±0.12 cm2/m2) were evaluated with transthoracic echocardiography. LV ejection fraction (LVEF) was calculated using biplane Simpson’s method. LV mechanical dispersion was calculated as standard deviation of time from Q wave on ECG to peak strain of 16 LV segments. Patients were followed for occurrence of all-cause mortality. Prognostic value of the 2 echocardiographic parameters was tested in different multivariable models.
Results: During 82±47 months follow-up, surgical or transcatheter aortic valve replacement (AVR) was performed in 267 (63%) patients and 165 (39%) patients died. Non-survivors demonstrated worse LVEF and longer mechanical dispersion compared to survivors (LVEF 54±13% vs 58±9%, p<0.001; mechanical dispersion 66±20 ms vs 53±15 ms, p<0.001; respectively). Baseline multivariable Cox proportional hazards model (table) included age, LV mass index and stroke volume index as significant univariates and AVR as a time-dependent co-variate (baseline model χ2 = 79.1). The mechanical dispersion model demonstrated significant χ2 increase (χ2= 94.1, p<0.001), in contrast to the LVEF model (χ2= 80.7, p = 0.921) that added no significant prognostic difference.
Conclusions: Non-survivors with severe AS had a significantly higher LV mechanical dispersion and worse LVEF at baseline. In contrast to LVEF, LV mechanical dispersion was a significant prognostic parameter associated with all-cause mortality, indicating it may be an additional risk marker in patients with severe AS.
Author Disclosures: E.A. Prihadi: None. M. Leung: None. E.M. Vollema: None. A. Ng: None. N. Ajmone Marsan: None. J.J. Bax: None. V. Delgado: Speakers Bureau; Modest; Abott Vascular.
- © 2016 by American Heart Association, Inc.