Echocardiographic predictors of cardiac improvement following coronary artery bypass grafting surgery

Objective To examine markers of improvement in left ventricular (LV) systolic function after coronary artery bypass grafting (CABG), assessed by changes (Δ) in LV ejection fraction (LVEF) and global longitudinal strain (GLS), and to evaluate the association between ΔLVEF/ΔGLS and all-cause mortality. Methods Patients who underwent isolated CABG from 2006 to 2011 at Gentofte Hospital with a preoperative echocardiography within 30 days before and postoperative echocardiography 30 to 365 days after surgery were included. Multivariable linear regression identified clinical and echocardiographic predictors of ΔLVEF and ΔGLS. Cox proportional hazards regression models related these changes to all-cause mortality. Results Among 226 patients (median age, 67 years, 14% women), LVEF improved from 48.5% ± 12.8% (pre-CABG) to 53.9% ± 9.8% (post-CABG) and GLS from 12.8% ± 4.4% to 13.6% ± 4.8% (absolute values, both P values < .001). Lower preoperative LVEF and GLS were the strongest independent determinants of postoperative improvement (β, −0.65; 95% CI, −0.75 to −0.55; and β, −0.51; 95% CI, −0.63 to −0.39; both P values < .001). Larger preoperative LV internal end-diastolic diameter was associated with greater LVEF improvement ( P = .014), whereas higher atrial strain and tricuspid annular plane systolic excursion were associated with greater GLS improvement (both P values < .05). Chronic kidney disease ( P = .040) and a history of heart failure ( P = .024) were associated with less GLS improvement. Each 1% absolute-increase in ΔLVEF or ΔGLS was associated with lower mortality after multivariable adjustment (hazard ratio, 0.88; 95% CI, 0.83 to 0.93, and 0.66; 95% CI, 0.56 to 0.78, respectively; both P values < .001). Conclusions Postoperative improvements in LVEF and GLS were common, occurred most often in patients with lower pre-CABG LV function, and were independently associated with reduced mortality.