ASSESSING LEFT VENTRICULAR FUNCTION BY GLOBAL LONGITUDINAL STRAIN ONE YEAR AFTER ST ELEVATION MYOCARDIAL INFARCTION

Objectives
Aim of this study was to explore changes in left ventricular global longitudinal strain (LV GLS) one year after STEMI and their potential prognostic value.

Materials and methods
Data were analyzed retrospectively from an ongoing STEMI registry. Patients with previous myocardial infarction, heart failure history, suboptimal image quality or missing follow-up were excluded. Transthoracic echocardiography was performed during the index hospitalization and one year after STEMI. Relative LV GLS (Δ GLS) change was calculated. The endpoint was all-cause mortality.

Results
The study population consisted of 1409 patients (mean age 60±11 years; 1059 (75%) men). Of all patients surviving at least one year after STEMI, a total of 87 patients died after a median follow-up of 69 (IQR 38-103) months. At one year follow-up LV EF improved from 50±8% to 53±8% (p<0.001) and LV GLS improved from 14±4% to 16±3% (p<0.001). Median ΔGLS was 14 (IQR 0.5-32)%. Optimal cut-off for Δ GLS was established on penalized spline curve as -7%. Cumulative 10-year survival was 91% in patients with Δ GLS >-7% versus 85% in patients with Δ GLS ≤-7% (p=0.001). On multivariate Cox regression analysis Δ GLS ≤-7% remained independently associated with the endpoint after adjustment for age, troponin T, kidney function, chronic obstructive pulmonary disease, wide QRS complex, TAPSE and baseline LV GLS (HR 2.5 (95% CI 1.5-4.1); p<0.001).

Conclusions
Significant improvement in LV GLS one year after STEMI has additional prognostic value on top of baseline LV GLS, clinical risk factors and right ventricular function.