A global longitudinal strain cut-off value to predict adverse outcomes in individuals with a normal ejection fraction

Abstract

Aims: Global longitudinal strain (GLS) has become an alternative to left ventricular ejection fraction (LVEF) to determine systolic function of the heart. The absence of cut-off values is one of the limitations preventing full clinical implementation. The aim of this study is to determine a cut-off value of GLS for an increased risk of adverse events in individuals with a normal LVEF. Methods and results: Echocardiographic images of 502 subjects (52% female, mean age 48 ± 15) with an LVEF ≥ 55% were analysed using speckle tracking-based GLS. The primary endpoint was cardiovascular death or cardiac hospitalization. The analysis of Cox models with splines was performed to visualize the effect of GLS on outcome. A cut-off value was suggested by determining the optimal specificity and sensitivity. The median GLS was −22.2% (inter-quartile range −20.0 to −24.9%). In total, 35 subjects (7%) had a cardiac hospitalization and/or died because of cardiovascular disease during a follow-up of 40 (5–80) months. There was a linear correlation between the risk for adverse events and GLS value. Subjects with a normal LVEF and a GLS between −22.9% and −20.9% had a mildly increased risk (hazard ratio 1.01–2.0) for cardiac hospitalization or cardiovascular mortality, and the risk was doubled for subjects with a GLS of −20.9% and higher. The optimal specificity and sensitivity were determined at a GLS value of −20.0% (hazard ratio 2.49; 95% confidence interval: 1.71–3.61). Conclusions: There is a strong correlation between cardiac adverse events and GLS values in subjects with a normal LVEF. In our single-centre study, −20.0% was determined as a cut-off value to identify subjects at risk. A next step should be to integrate GLS values in a multi-parametric model.