Incremental value of global longitudinal strain for predicting early outcome after cardiac surgery

Aims Global longitudinal strain (GLS) seems accurate for detecting subclinical myocardial dysfunction, and may therefore be used to improve risk stratification for cardiac surgery. Methods and results Longitudinal strain (by two-dimensional speckle tracking) was computed in 425 patients [mean age 67 +/- 13 years, 69% male, left ventricular ejection fraction (LVEF) 51 +/- 13%] referred for cardiac surgery [isolated coronary artery bypass graft (CABG) (n = 155), aortic valve surgery (n = 174), mitral surgery (n = 96)]. GLS (global-epsilon) was assessed for predicting early postoperative death. Despite a fair correlation between LVEF and global strain (r = -0.73, P < 0.0001), 40% of patients with preserved LVEF (defined as LVEF >= 50%) had abnormal global-epsilon (defined as global-epsilon > -16%): -12.8 +/- 1.7%, range -15% to -8%. In patients with preserved LVEF, NT-proBNP level (983 vs. 541 pg/mL, P = 0.03), heart failure symptoms (NYHA class, 2.2 +/- 0.9 vs. 1.9 +/- 0.9, P = 0.02), and the need for prolonged (>48 h) inotropic support after surgery (33.3 vs. 21.2%, P = 0.03) were greater when global-epsilon was impaired. Importantly, despite similar EuroSCORE (9.7 +/- 12 vs. 7.7 +/- 9%, P=0.2 for EuroSCORE I and 4.2 +/- 6.2 vs. 3.4 +/- 4.9%, P = 0.4 for EuroSCORE II), the rate of postoperative death was 2.4fold (11.8 vs. 4.9%, P = 0.04) in patients with preserved LVEF when global-epsilon was impaired. Multivariate analysis showed that global-epsilon is an independent predictor for early postoperative mortality [odds ratio = 1.10 (1.01-1.21)] after adjustment to EuroSCORE. Conclusion GLS has an incremental value over LVEF for risk stratification in patients referred for cardiac surgery.