Usefulness of Global Left Ventricular Longitudinal Strain for Risk Stratification in Low Ejection Fraction, Low-Gradient Aortic Stenosis: Results From the Multicenter True or Pseudo-Severe Aortic Stenosis Study
From the Institut Universitaire de Cardiologie et de Pneumologie de Québec/Québec Heart and Lung Institute, Laval University, Québec City, Québec, Canada (A.D., R.C., M.-A.C., S.L.G., J.G.D., M.S., K.O’C., P.P.); Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna, Vienna, Austria, (P.E.B., G.M., J.B.-K.); University of Ottawa Heart Institute, Ottawa, Ontario, Canada (I.B.); and Division of Adult Congenital and Valvular Heart Disease, Department of Cardiovascular Medicine, University Hospital Muenster, Muenster, Germany (H.B.).
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Background—The objective of this study was to examine the impact of left ventricular (LV) global longitudinal strain (GLS) measured at rest and at dobutamine stress echocardiography on the outcome of patients with low LV ejection fraction and low-gradient aortic stenosis.Methods and Results—Among the 202 patients with low LV ejection fraction (≤40%), low-gradient aortic stenosis (mean transvalvular gradient <40 mm Hg and indexed aortic valve area ≤0.6 cm2/m2) prospectively enrolled in the multicenter True or Pseudo-Severe Aortic Stenosis study, 126 patients with resting GLS and 73 patients with stress GLS available were included in this substudy. Three-year survival rate was 49% in patients with rest GLS <|9|% compared with 68% in patients with GLS >|9|% (P=0.02). In a multivariable Cox model adjusted for age, coronary artery disease, projected aortic valve area at a normal flow rate and type of treatment (aortic valve replacement versus conservative), rest GLS <|9|% (hazard ratio, 2.18; P=0.015) remained independently associated with all-cause mortality. GLS <|10|% measured during dobutamine stress echocardiography was also independently associated with mortality (hazard ratio, 2.67; P=0.01). In the subset of patients with stress GLS (n=73), the χ2 of the multivariable model to predict all-causes mortality was 21.96 for stress GLS versus 17.78 for rest GLS.Conclusions—GLS is independently associated with mortality in patients with low LV ejection fraction, low-gradient aortic stenosis. Stress GLS measured during dobutamine stress echocardiography may provide incremental prognostic value beyond GLS measured at rest. Hence, measurement of GLS at rest and during dobutamine stress echocardiography may be helpful to enhance risk stratification in low LV ejection fraction, low-gradient aortic stenosis.Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT01835028.