Incremental Prognostic Value of Left Ventricular Longitudinal Strain Over Ejection Fraction in Coronary Artery Bypass Grafting

Abstract

Objectives: To evaluate the incremental prognostic value of longitudinal strain over left ventricular ejection fraction (LVEF) after coronary artery bypass grafting (CABG).

Design: Retrospective cohort study.

Setting: Single tertiary-care center.

Participants: Patients underwent isolated CABG between January 2014 and December 2019.

Interventions: None.

Measurements and main results: There were 999 patients (median age, 65 years, 23.5% female) categorized into 3 groups according to their left ventricular (LV) systolic function status: pEF/pS (preserved LVEF and preserved longitudinal strain, n = 490), pEF/iS (preserved LVEF and impaired longitudinal strain, n = 186), and rEF (reduced LVEF, n = 323). During a median follow-up of 2.7 years, 86 (8.6%) patients had died. The 5-year survival significantly differed in patients with preserved LVEF according to the strain status (pEF/pS v pEF/iS, 90.0% v 84.6%; p = 0.002). After adjusting for potential confounders, the pEF/iS group (adjusted hazard ratio [HR], 2.17; 95% CI, 1.10-4.28; p = 0.03) and the rEF group (adjusted HR, 2.96; 95% CI, 1.46-6.00; p = 0.003) had significantly higher risks for all-cause death compared with the pEF/pS group. The addition of longitudinal strain to LVEF in the prediction model significantly improved its performance (global chi-squared, 105.2 v 110.2; p = 0.03).

Conclusions: Left ventricular longitudinal strain could differentiate the prognosis after CABG in patients with preserved LVEF and provide significant incremental prognostic value to LVEF.

Keywords: coronary artery bypass grafting; left ventricular ejection fraction; left ventricular longitudinal strain; survival.