Dimensionless Index in Patients With Low-Gradient Severe Aortic Stenosis and Preserved Ejection Fraction.

Background Risk stratification of patients with low-gradient (LG) severe aortic stenosis (AS) despite preserved left ventricular ejection fraction remains challenging. We sought to evaluate the relationship between the dimensionless index (DI)-the ratio of the left ventricular outflow tract time-velocity integral to that of the aortic valve jet-and mortality in these patients. Methods Seven hundred fifty-five patients with LG severe AS (defined by aortic valve area ≤1 cm2 or aortic valve area indexed to body surface area ≤0.6 cm2/m2 and mean aortic pressure gradient <40 mm Hg) and preserved left ventricular ejection fraction ≥50% were studied. Flow status was defined according to stroke volume index <35 mL/m2 (low flow, LF) or ≥35 mL/m2 (normal flow, NF). Results After adjustment for age, sex, body mass index, Charlson comorbidity index, history of hypertension, history of atrial fibrillation, AS-related symptoms, left ventricular ejection fraction, indexed left ventricular ventricular mass, aortic valve area, and aortic valve replacement as a time-dependent covariate, patients with LG-LF and DI<0.25 exhibited a considerable increased risk of death compared with patients with LG-NF and DI≥0.25 (adjusted hazard ratio, 2.41 [95% CI, 1.61-3.62]; P<0.001), LG-NF and DI<0.25 (adjusted hazard ratio, 1.84 [95% CI, 1.24-2.73]; P=0.003), and LG-LF and D≥0.25 (adjusted hazard ratio, 2.27 [95% CI, 1.42-3.63]; P<0.001). In contrast, patients with LG-LF and DI≥0.25, LG-NF and DI<0.25, and LG-NF and DI≥0.25 had similar outcome. DI<0.25 showed incremental prognostic value in patients with LG-LF severe AS but not in patients with LG-NF severe AS. Conclusions Among patients with LG severe AS and preserved left ventricular ejection fraction, decreased DI<0.25 is a reliable parameter in patients with LF to identify a subgroup of patients at higher risk of death who may derive benefit from aortic valve replacement.

Prognostic Importance of Left Ventricular Global Longitudinal Strain in Patients with Severe Aortic Stenosis and Preserved Ejection Fraction.

BACKGROUND: Impaired left ventricular (LV) speckle-tracking-derived global longitudinal strain (GLS) magnitude (GLS worse than 14.7%) has been associated with poor outcome in patients with severe aortic stenosis (AS) and preserved LV ejection fraction (EF). OBJECTIVES: To test the hypothesis that GLS magnitude ≤ 15% obtained with vendor-independent speckle-tracking strain software may be able to identify patients with severe AS who are at higher risk of death, despite preserved LVEF and no or mild symptoms. METHODS: GLS was retrospectively obtained in 332 patients with severe AS (aortic valve area indexed [AVAi] < 0.6 cm2/m2), no or mild symptoms, and LVEF ≥ 50%. Absolute values of GLS were collected. Survival analyses were carried out to study the impact of GLS magnitude on all-cause mortality. RESULTS: During a median follow-up period of 42 (37-46) months, 105 patients died. On multivariate analysis, and after adjustment of known clinical and/or echocardiographic predictors of outcome and aortic valve replacement as a time-dependent covariate, GLS magnitude ≤ 15% was independently associated with mortality during follow-up (all P < .01). Adding GLS magnitude ≤ 15% (adjusted hazard ratio = 1.99 [1.17-3.38], P = .011) to a multivariate model including clinical and echocardiographic variables of prognostic importance (aortic valve replacement, aortic valve area, LV stroke volume index < 30 mL/m2, and LVEF<60%) improved the predictive performance with improved global model fit, reclassification, and better discrimination. After propensity score matching (n = 196), increased risk of mortality persisted among patients with GLS magnitude ≤ 15% compared with those with GLS > 15% (hazard ratio = 2.10; 95% confidence interval, 1.20-3.68; P = .009). CONCLUSIONS: In this series of patients with severe AS, no or mild symptoms, and LVEF ≥ 50%, GLS obtained with vendor-independent speckle-tracking strain software was an effective tool to identify patients with a poor outcome. Detection of myocardial dysfunction by identifying GLS magnitude < 15% in patients with severe AS, no or mild symptoms, and LVEF ≥ 50%, can aid in risk assessment.