Abstract 14578: A Meta-analysis of Global Longitudinal Strain as a Predictor of Major Adverse Cardiac Events in Severe, Asymptomatic Aortic Stenosis With Preserved Ejection Fraction

Abstract

Introduction: The timing of surgical intervention in aortic stenosis (AS) is critical. Guidelines recommend aortic valve replacement in severe, asymptomatic AS with an ejection fraction (EF) less than 50%. Two-dimensional speckle tracking echocardiography is a relatively novel way to identify left ventricular dysfunction by measuring myocardial strain. Global longitudinal strain (GLS) is a measurement of deformation of the myocardium, and is considered a more sensitive marker for left ventricular dysfunction than EF. Hypothesis: Our aim was to determine if abnormal GLS predicts poor outcomes in severe, asymptomatic AS patients with a preserved EF. Methods: We conducted a meta-analysis and searched MEDLINE, EMBASE, Cochrane (2000 to 2015), supplemented by manual bibliographies of key relevant articles. We selected all cohort, cross-sectional, and case-control studies in which GLS was measured and major adverse cardiac events (MACE) were reported. In the case-control studies, we calculated the pooled standard mean difference (SMD) of GLS between those with MACE and those without MACE. In cohort studies, we calculated the pooled relative risk (RR) with the corresponding 95% confidence interval (CI) for incident MACE by using the fixed effects method. Results: Our search strategy identified 3 studies that met the inclusion criteria, and included 370 AS patients. Of the 3 studies, all reported data using a case-control design and 2 reported data using a cohort design. The median age of AS patients included was 72.6 years old, the median indexed aortic valve area was 0.44 (cm 2 /m 2 ), and the median ejection fraction was 64.2 (%). Of the 370 patients included in the analysis, 183 had MACE. Case-control studies revealed a pooled GLS SMD of 0.5 (95% CI: 0.30-0.69, p<0.01) for patients with MACE compared to those without MACE. Cohort studies revealed a RR of MACE of 2.07 (95% CI: 1.59-2.69, p<0.01) for those with abnormal GLS compared to those normal GLS. Conclusions: AS patients with a more positive global longitudinal strain value were more likely to have a major adverse cardiac event despite having a preserved EF and absence of symptoms. Therefore, if abnormal GLS is detected, earlier surgical intervention should be considered in severe, asymptomatic aortic stenosis.