Prognostic Value of Follow-up Measures of Left Ventricular Global Longitudinal Strain in Patients with ST-segment elevation Myocardial Infarction.

INTRODUCTION: After ST-segment elevation myocardial infarction (STEMI), follow-up imaging is currently recommended only in patients with left ventricular ejection fraction (LVEF) <40%. LV global longitudinal strain (GLS) showed to improve risk stratification over LVEF in these patients, but has not been thoroughly studied during follow-up. 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 one year after STEMI; LVGLS was expressed as absolute value and the relative LVGLS change (ΔGLS) was calculated. The study endpoint was all-cause mortality.

RESULTS: A total of 1409 STEMI patients (age 60±11 years; 75% men), who survived at least one year after STEMI and underwent echocardiography at follow-up, were included. At one year follow-up, LVEF improved from 50±8% to 53±8% (p<0.001) and LVGLS from 14±4% to 16±3% (p<0.001). Median ΔGLS was 14 (IQR 0.5-32)% relative improvement. Starting one year after STEMI, a total of 87 patients died after a median follow-up of 69 (IQR 38-103) months. The optimal ΔGLS threshold associated with the endpoint (derived by spline curve analysis) was a relative decrease >7%. Cumulative 10-year survival was 91% in patients with ΔGLS improvement or a non-significant decrease, versus 85% in patients with ΔGLS decrease of >7% (p=0.001). On multivariate Cox regression analysis, ΔGLS decrease >7% remained independently associated with the endpoint (HR 2.5 (95% CI 1.5 - 4.1); p<0.001) after adjustment for clinical and echocardiographic parameters.

CONCLUSIONS: A significant decrease in LVGLS one 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.