Abstract Body (Do not enter title and authors here):
Background: The optimal clinical management and timing of intervention are less well defined in paradoxical low-flow, low-gradient severe aortic stenosis (PLFLG AS). Left ventricular global longitudinal strain (LV-GLS) has been shown to predict outcomes in high flow severe AS, but there is lack of data in patients with PLFLG AS. Given the exaggerated LV hypertrophy and remodeling pattern in PLFLG AS, LV-GLS may be a mechanistic imaging marker for worse outcomes.

Hypothesis: In patients with PLFLG AS, LV-GLS is associated with adverse clinical outcomes by detecting subclinical myocardial fibrosis resulting from myocardial remodeling due to LV pressure overload.

Methods: We examined patients with PLFLG AS defined as AVA <1cm², mean gradient <40mmHg and preserved left ventricular ejection fraction (LVEF) ≥50%, with low-flow state defined as transvalvular flow rate (Q) ≤210 ml/sec. Exclusion criteria included moderate or greater mitral or aortic regurgitation and presence of atrial fibrillation at the time of echocardiogram. LV strain analysis was performed using 2D-strain imaging software (TomTec, Chicago, IL). Clinical outcome data were obtained via the electronic health record. The primary outcome was defined as all-cause mortality. Patients were stratified by LV-GLS above and below the median value.

Results: A total of 198 patients were included in the analysis, with a median LV-GLS of -12.3% [IQR: (-9.8,-16.3)]. Over a median follow-up time of 1.2 years, 130 deaths (65.6%) were identified. Patients with less negative LV-GLS (n=101) had worse survival than those with more negative LV-GLS (n=97; 22 vs 38%; p=0.02) (Fig 1). After multivariable adjustment for potential confounders (stroke volume index, aortic valve mean gradient, relative wall thickness, age, sex, heart failure, hypertension, coronary artery disease, and diabetes), less negative LV-GLS was independently associated with adverse outcomes (HR 1.56; 95% CI (1.03-2.38); p=0.04).

Conclusions: In patients with PLFLG AS as defined by a transvalvular flow rate (Q) ≤210 ml/sec, reduced LV-GLS is associated with increased all-cause mortality. LV-GLS may serve as an imaging marker to help guide clinical decision making in PLFLG AS.