Prognostic Value of Follow-up Measures of Left Ventricular Global Longitudinal Strain in Patients With ST-Segment Elevation Myocardial Infarction

Abstract

Introduction: After ST-segment elevation myocardial infarction (STEMI), follow-up imaging is currently recommended only in patients with left ventricular ejection fraction (LVEF) <40%. Left ventricular global longitudinal strain (LVGLS) was shown to improve risk stratification over LVEF in these patients but has not been thoroughly studied during follow-up. The aim of this study was to explore the changes in LVGLS after STEMI and their potential prognostic value. Materials and methods: Data were analyzed from an ongoing STEMI registry. Echocardiography was performed during the index hospitalization and 1 year after STEMI; LVGLS was expressed as an absolute value and the relative LVGLS change (Delta GLS) was calculated. The study end point was all-cause mortality. Results: A total of 1,409 STEMI patients (age 60 +/- 11 years; 75% men) who survived at least 1 year after STEMI and underwent echocardiography at follow-up were included. At 1-year follow-up, LVEF improved from 50% +/- 8% to 53% +/- 8% (P < .001) and LVGLS from 14% +/- 4% to 16% +/- 3% (P < .001). Median Delta GLS was 14% (interquartile range, 0.5%-32%) relative improvement. Starting 1 year after STEMI, a total of 87 patients died after a median follow-up of 69 (interquartile range, 38-103) months. The optimal Delta GLS threshold associated with the end point (derived by spline curve analysis) was a relative decrease >7%. Cumulative 10-year survival was 91% in patients with Delta GLS improvement or a nonsignificant decrease, versus 85% in patients with Delta GLS decrease of >7% (P = .001). On multivariate Cox regression analysis, Delta GLS decrease >7% remained independently associated with the end point (hazard ratio, 2.5 [95% CI, 1.5-4.1]; P < .001) after adjustment for clinical and echocardiographic parameters. Conclusions: A significant decrease in LVGLS 1 year after STEMI was independently associated with long-term all-cause mortality and might help further risk stratification and management of these patients during follow-up.