Prognostic Value of Left Ventricular Deformation Parameters in Patients with Severe Aortic Stenosis: A Pilot Study of the Usefulness of Strain Echocardiography

Background: In patients with aortic stenosis, subtle alterations in myocardial mechanics can be detected by speckle-tracking echocardiography before reduction of left ventricular ejection fraction (LVEF). Methods: In this prospective study, 162 patients with aortic stenosis with an average aortic valve area of 0.7 +/- 0.2 cm(2) and a mean LVEF of 60 +/- 11% were included. Global longitudinal strain (GLS) and mechanical dispersion (SD of time from Q/R on the electrocardiogram to peak strain in 16 left ventricular segments) were assessed using echocardiography, and all-causemortality (n=37) was recordedduring37 +/- 13 months of follow-up. Results: Overall, nonsurvivors had more pronounced mechanical dispersion and worse GLS compared with survivors (74 +/- 24 vs 61 +/- 18 msec [P<.01] and -14.5 +/- 4.4% vs -16.7 6 +/- 3.6% [P <.01], respectively). In the 42 conservatively treated patients without surgical aortic valve replacement, a similar pattern was observed in nonsurvivors versus survivors (mechanical dispersion, 80 +/- 24 vs 57 +/- 14 msec [P <.01]; GLS, -14.0 6 +/- 4.9% vs -17.1 6 +/- 3.8% [P =.04], respectively). Mechanical dispersion was significantly associated with mortality (hazard ratio per 10-msec increase, 1.23; 95% CI, 1.07-1.42; P <.01) in a Cox model adjusted for LVEF and with aortic valve replacement treatment as a time-dependent covariate. Continuous net reclassification improvement showed that mechanical dispersion was incremental to LVEF, GLS, and valvulo-arterial impedance when adjusting for aortic valve replacement treatment in the total population. Conclusion: Increased mechanical dispersion may be a risk marker providing novel prognostic information in patients with aortic stenosis.