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ObjectiveTo determine the prognostic value of global longitudinal strain (GLS) after coronary artery bypass grafting (CABG).MethodsWe performed a retrospective cohort study on patients undergoing CABG between 2006 and 2011 who had an echocardiogram available for strain analysis. The patients were followed up through nationwide registries for development of all-cause mortality, cardiovascular death (CVD) and major adverse cardiovascular events (MACEs) defined as heart failure hospitalisation and/or CVD. Multivariable Cox regression was applied to adjust for the European System for Cardiac Operative Risk Evaluation II (EuroSCORE-II). Additive value was assessed by Net Reclassification Index (NRI) improvement.ResultsOf the 709 patients included, 80 died during a median follow-up of 3.8 years. Of these, 45 had CVD, and 72 patients experienced MACE. Mean age was 68 years and 85% were men. Left ventricular ejection fraction (LVEF) was 50% and GLS was −13%.GLS was an independent predictor when adjusted for the EuroSCORE-II (all-cause mortality: HR=1.07 (1.01–1.13), p=0.018; CVD: HR=1.11 (1.03–1.20), p=0.007; MACE: HR=1.12 (1.06–1.19), p<0.001, per 1% absolute decrease). GLS significantly improved the NRI score by 0.30 when added to the EuroSCORE-II for predicting MACE, but not significantly for the other endpoints.LVEF modified the association between GLS and outcomes (p for interaction<0.05 for CVD and MACE). GLS remained an independent predictor of outcomes in patients with preserved LVEF (LVEF≥50%) and improved the NRI score when added to the EuroSCORE-II for predicting CVD and MACE, but not all-cause mortality in these patients.ConclusionGLS is an independent predictor of long-term outcomes after CABG. The predictive value appears strongest among patients with preserved LVEF.

Introduction:Sectionalized quantification of layer-specific global longitudinal strain (GLS) has recently become available with new technological advancements. We sought to investigate the prognostic value of layer-specific strain in patients undergoing coronary artery bypass grafting (CABG).Methods:This retrospective cohort study comprised patients undergoing isolated CABG between 2006 and 2011. The patients were followed through nation-wide registries for the composite endpoint of heart failure (HF) or cardiovascular death (CVD) (HF/CVD). Multivariable Cox regression models adjusted for clinical and echocardiographic baseline characteristics, as well as European System for Cardiac Operative Risk Evaluation II (EuroSCORE II) were used to assess the association between layer-specific GLS and the endpoint.Results:Of 641 patients included (mean age 67 years, 84% male), 62 experienced the composite of outcome (HF: n=30, CVD: n=38) during a median follow-up of 3.8 years. Patients who developed the outcome during follow-up had reduced layer-specific GLS in all layers (GLSendo: -14.3% vs. -16.3; GLSww: -12.2 vs. -13.9; GLSepi: -10.7 vs. -12.2). Additionally, all layer-specific GLS parameters were predictors of outcome in unadjusted models (GLSendo: HR=1.11 (1.05-1.17); GLSww: HR=1.13 (1.06-1.21); GLSepi: HR=1.15 (1.07-1.24), per 1% absolute decrease). The risk of the endpoint increased linearly with decreasing absolute GLS for all layers (Figure 1). These findings were unchanged in multivariable models. Patients with reduced GLS in any layer had a higher risk of HF/CVD, however, the risk was highest for those with reduced epicardial GLS (HR=2.60 (1.46-4.66), p=0.001).Conclusions:Layer-specific GLS is an independent prognosticator of cardiovascular events after CABG. Reduced epicardial GLS poses the highest risk of HF/CVD.