Page 123 - The role of advanced echocardiography in patients with ischemic heart disease - Rachid Abou
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DISCUSSION
The main findings of the present study can be summarized as follows: in a homogenous contemporary STEMI population with mildly reduced or preserved LVEF, patients who died during follow-up had more impaired LV GLS at all layers (endomyocardial, mid-myocardial and epicardial, reflecting more extensive scar tissue) at baseline echocardiography when compared to their counterparts. In contrast, we observed no differences in enzymatic infarct size nor LVEF between survivors and non-survivors. Furthermore, multivariable analysis demonstrated that aging and reduced LV GLS of the epicardial layer (reflecting transmural infarction) were independently associated with higher risk of all-cause mortality. Finally, reduced LV GLS at the epicardium shows significant incremental value for prediction of all-cause mortality after adjusting for clinical, biological and echocardiographic variables.
In current clinical practise, echocardiography plays a central role in the evaluation of 6 regional and global LV systolic function after acute myocardial infarction.1 LV systolic
function (before hospital discharge) remains an important predictor of survival in
patients after acute myocardial infarction.1 Currently, contemporary guidelines recommend LVEF assessment, and not LV GLS, as the main measurement of LV
systolic function in patients after acute myocardial infarction.10 However, LV GLS has been shown to be superior over LVEF in terms of reproducibility and prediction of hard events such as all-cause and cardiovascular mortality.4 In addition, LV GLS is a more sensitive measure of LV systolic dysfunction and may be impaired while LVEF is still within the normal range.16,17 It has been hypothesized that an increase in radial and circumferential strain may compensate for reduced longitudinal strain (as longitudinal strain is more prone to myocardial injury) and therefore LVEF remains preserved.18,19 Therefore, LV GLS is considered a more sensitive marker of LV systolic dysfunction when compared to traditional echocardiographic parameters such as LVEF.
Layer-specific LV GLS allows for a more comprehensive understanding of LV systolic function.20-22 Several studies have shown the clinical value of layer-specific LV GLS in patients with coronary artery disease.23-25 Similar, conflicting results are reported on which layer yields the best prognostic value. Hamada et al 26 showed in a study including 390 patients with chronic ischemic cardiomyopathy that LV GLS and particularly global circumferential strain at the endocardium was associated with adverse cardiac events (readmission, worsening of heart failure, ventricular arrhythmias or all-cause mortality) independent of LVEF and transmural scar assessed on cardiac magnetic resonance. However a recent study by Skaarup et al 7, including 465 patients after
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