Abstract 13655: Impact of Global Left Ventricular Longitudinal Strain on Outcomes in Low-Flow, Low-Gradient Aortic Stenosis

Abstract

Introduction: Recent studies suggest that LV global longitudinal strain (GLS) may be a more sensitive marker of intrinsic myocardial function than LV ejection fraction (LVEF) or stroke volume in patients with aortic stenosis (AS) and preserved LV ejection fraction (LVEF). The objective of this study was to examine the impact of GLS measured at rest and at peak dobutamine stress on the outcome of patients with LF-LG AS.

Method: 200 patients with LF-LG AS were prospectively enrolled in the multicenter TOPAS study. Inclusion criteria were LVEF≤40%, mean gradient <40 mmHg, and indexed effective orifice area (EOA)<0.6 cm²/m².

Results: GLS measurement was feasible in 126 of the 200 patients. Among the 126 patients, 67 (53%) underwent surgical or transcatheter aortic valve replacement (AVR) within 3 months of enrollment and the remaining were treated medically. During a mean follow up of 2.1±1.9 years, 48 patients died. The 3 year survival rate was 49% in patients with GLS9.4% (p=0.01). After adjustment for type of treatment (AVR vs. medical), resting GLS (HR=1.11 per 1% decrease in GLS; p=0.03), peak stress GLS (HR=1.21 per 1% decrease; p=0.001), and absolute change in GLS (ΔGLS) during dobutamine (HR=1.17 per 1% decrease; p=0.03), were significant predictors of all-cause mortality. Resting LVEF (HR=1.04 per 1% decrease in LVEF; p=0.04) was also a significant predictor of mortality, with a trend for peak stress LVEF (HR=1.03; p=0.06). In multivariable analysis adjusted for age, gender, coronary artery disease, projected EOA at a normal flow rate (250 ml/s), and type of treatment, resting GLS (HR=1.10; p=0.04) and peak stress GLS (HR=1.19; p=0.003) were independent predictors of mortality, whereas ΔGLS (HR=1.10; p=0.21), resting LVEF (HR=1.03; p=0.07), and peak stress LVEF (HR=1.02; p=0.12) were not.

Conclusion: GLS is a powerful independent predictor of mortality in patients with LF-LG AS. Furthermore, GLS is superior to LVEF to predict mortality, most likely because it better reflects intrinsic myocardial contractility. Peak stress GLS measured during dobutamine stress echocardiography may provide incremental prognostic value beyond GLS measured at rest, but this remains to be confirmed in further studies with a larger number of patients.