Global longitudinal strain predicts cardiovascular events after coronary artery bypass grafting

OBJECTIVE: To determine the prognostic value of global longitudinal strain (GLS) after coronary artery bypass grafting (CABG).

METHODS: We 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.

RESULTS: Of 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.

CONCLUSION: GLS is an independent predictor of long-term outcomes after CABG. The predictive value appears strongest among patients with preserved LVEF.