Longitudinal strain provides prognositic value, incremental to that of cardiac magnetic resonance at the acute phase in patients with st-segment elevation myocardial infarction
Résumé
Objectives: We assessed the value of speckle tracking imaging performed early after a first ST-segment elevation myocardial infarction (STEMI) in order to predict infarct size and functional recovery at 3-month follow-up. Methods: Forty-four patients with STEMI who underwent revascularization within 12 h of symptom onset were prospectively enrolled. Echocardiography was performed 3.9±1.2 days after myocardial reperfusion, assessing circumferential (CGS), radial (RGS), and longitudinal global (GLS) strains. Late gadolinium-enhanced cardiac magnetic imaging (CMR), for assessing cardiac function, infarct size, and microvascular obstruction (MVO), was conducted 5.6±2.5 days and 99.4±4.6 days after myocardial reperfusion. Results: GLS was evaluable in 97% of the patients, while CGS and RGS could be assessed in 85%. Infarct size significantly correlated with GLS (R=0.601, p<0.001), RGS (R=-0.405, p=0.010), CGS (R=0.526, p=0.001), ejection fraction (R=-0.699, p<0.001), wall motion score index (R=0.539, p=0.001), and left atrial volume (R=0.510, p<0.001). Baseline ejection fraction and GLS were independent predictors of 3-month infarct size. MVO mass significantly correlated with GLS (R=0.391, p=0.010), RGS (R=-0.259, p=0.066), wall motion score index (R=0.387, p=0.011), and ejection fraction (R=-0.389, p=0.011). In multivariate analysis, GLS was the only independent predictor of MVO mass (p=0.02). Longitudinal strain >-6.0% within the infarcted area exhibited 96% specificity and 61% sensitivity for predicting the persistence of akinesia (≥3 segments) at 3-month follow-up. Conclusions: Speckle-tracking strain imaging performed early after a STEMI is an easy-to-use tool for predicting persistent akinetic territories at 3 months. In addition, GLS correlated significantly with MVO and final infarct size, both parameters being relevant post-MI prognostic factors, usually obtained via CMR.