Page 104 - The role of advanced echocardiography in patients with ischemic heart disease - Rachid Abou

Chapter five. Layer-specific LV GLS and remodeling
who underwent primary PCI. Joyce et al 6 demonstrated a significant incremental value of LV GLS for prediction of increase in LVEDV (net reclassification improvement index; 0.14, p=0.004) over clinical, biological and conventional echocardiographic (WMSI) parameters. These findings suggest an important role for LV GLS in the risk stratification of patients after STEMI.
Several studies have shown that layer-specific LV GLS allows accurate discrimination of LV myocardial infarct size as evaluated by cardiac magnetic resonance (CMR). 10,26,27 It is suggested that the layer-specific measurements of the endocardium more accurately discriminate non-infarcted areas from non-transmural infarct areas, whereas the epicardium better differentiates between non-transmural infarction and transmural infarcted areas. 27 Furthermore, Abate et al 28 evaluated 213 STEMI patients, with 40 undergoing CMR. Abate et al 28 demonstrated that LV epicardial twist by STE was correlated with myocardial infarct size. In addition, Abate et al performed a layer-specific analysis and demonstrated that LV epicardial twist provided incremental value over clinical and echocardiographic (LVEDV and LVEF) parameters for prediction of LV remodeling (defined as LV-end systolic volume increase ≥15%) at 6 months follow-up.28 Since the endocardial orientated fibers are predominantly responsible for the longitudinal function and primarily affected in ischemic heart disease 29, the mid-myocardium and the epicardial layer predominantly contribute to thickening and to radial and circumferential function. These mid-myocardium and epicardial layers prevent further LV dilatation and thus preserve global LV systolic function since they reflect the extent of myocardial infarct size.30 The current study demonstrated that layer-specific (endocardial, mid-myocardial and epicardial) LV GLS provides significant incremental value for prediction of adverse LV remodeling over clinical, biological and conventional echocardiographic parameters (such as LVEF and WMSI). Still, the model containing the epicardial LV GLS appears to be the best fit model to predict LV remodeling at 6 months follow-up. This suggests that a more preserved LV GLS at the epicardium reflects a smaller myocardial infarct size and less adverse remodeling.
Clinical application
Layer-specific LV GLS by 2D-STE allows for a better understanding of LV mechanics in ischemic heart disease and may reflect the amount of myocardial infarct size. Also, analysis of layer-specific LV GLS can be performed fast, offline and without the use of radiation, contrast media or cardiac stressors. Thus, layer-specific LV GLS may be beneficial in the early recognition of STEMI patients in need of aggressive anti- remodeling therapy, device therapy or more extensive follow-up.
98