Incremental Prognostic Value of Left Ventricular Global Longitudinal Strain in Patients With Aortic Stenosis and Preserved Ejection Fraction

Abstract

Background— We sought to assess the utility of left ventricular global longitudinal strain (LV-GLS) in predicting mortality in moderate to severe and paradoxical severe aortic stenosis (AS) patients with preserved ejection fraction. Methods and Results— We studied 395 AS patients (70±14 years, 57% men) with aortic valve area <1.3 cm 2 evaluated between January to June 2008 (excluding severe other valve disease and LV ejection fraction <50%). Clinical and echocardiographic data were recorded. LV-GLS was analyzed using Velocity Vector Imaging. AS patients were classified as (a) moderate–severe (n=93; aortic valve area, 1.1–1.3 cm 2 ), (b) standard severe (n=161; aortic valve area, ≤1 cm2; mean gradient ≥40 mm Hg), and (c) paradoxical severe (n=141; aortic valve area, ≤1 cm2 and mean gradient <40 mm Hg). Additive Euroscore was 7±3. The association of LV-GLS with all-cause mortality was assessed after risk-adjustment using Cox proportional hazards models. Median LV-GLS was −14.8% (interquartile range, −17.2%, −12.1%). At 4.4±1.4 years, there were 92 (23%) deaths. On multivariable Cox analysis, additive Euroscore (hazard ratio, 1.19; 1.13–1.27; P <0.001), New York Heart Association class (hazard ratio, 1.44; 1.11–1.87; P <0.001), AV surgery with time-dependent covariate analysis (hazard ratio, 0.29; 0.19–0.45; P <0.001), and LV-GLS (hazard ratio, 1.05; 1.03–1.07; P <0.001) were independent predictors of mortality. LV-GLS <−12.1% (4th quartile) was associated with significantly reduced survival. Addition of LV-GLS to clinical parameters (additive Euroscore+New York Heart Association class) led to significant improvement in prediction of mortality (χ 2 increased from 48 to 58; P <0.01). Conclusions— LV-GLS independently predicts mortality in moderate–severe and severe AS patients with preserved LV ejection fraction, providing incremental prognostic utility, in addition to standard clinical and echocardiographic parameters.

Outcomes in Asymptomatic Severe Aortic Stenosis With Preserved Ejection Fraction Undergoing Rest and Treadmill Stress Echocardiography

“…Also, we included patients over a broad time‐frame and not all imaging data (AV gradients on peak stress echocardiography11, 12 or AV calcium scoring on computed tomography) were available in all patients. As a prognostic cutoff, LV‐GLS of −17% is higher than what has been previously reported by our institution in severe AS; however the current cohort was purely asymptomatic patients as opposed to the previous report 30. The current study only reports associations, not causality.…”

“…Therefore, objective and reproducible parameters that identify early LV dysfunction, before a drop in LVEF could potentially allow more appropriate timing of surgery and in turn, allow improved survival. Over the past decade, the relationship between global LV load and abnormal LV systolic performance in AS patients, even in those with preserved LVEF has become more apparent, and the use of novel echocardiographic measures of LV load (Zva)19, 20, 45 and LV systolic performance (LV‐GLS)18, 30, 46 have been proposed as potential markers of early dysfunction, providing incremental prognostic utility.…”

“…The frame rate was >30 frames per second. LV‐GLS was analyzed offline using Velocity Vector Imaging (Syngo VVI, Siemens Medical Solutions, Mountain View, CA) as previously described 30. After manual definition of LV endocardium, it was automatically tracked throughout the cardiac cycle.…”

Exercise-induced changes in left ventricular global longitudinal strain in asymptomatic severe aortic stenosis

“…In the study by Kusunose et al [23], GLS > -12.1% was associated with significantly reduced survival after surgery despite normal LVEF.…”

The Future of Cardiovascular Imaging

“…[38][39][40][41][42][43] Although EF may be normal despite these structural changes, sensitive functional measures of LV contractility such as strain and strain rate are now able to provide incremental prognostic information and guide timing of intervention before major morbidity and mortality occurs. [44][45][46] The focus in regurgitant valvular diseases, such as mitral regurgitation, has mostly centered on regurgitant volume, the functional regurgitant orifice size, and the impact of the volume overload on chamber geometry and function in conjunction with functional capacity. Guideline recommendations for timing of intervention have been built around these relatively simple parameters but are known to be imprecise.…”