Page 124 - The role of advanced echocardiography in patients with ischemic heart disease - Rachid Abou

Chapter six. Layer-specific LV GLS and prognosis
acute coronary syndrome (STEMI, non-STEMI and unstable angina) demonstrated that LV GLS measured at all layers was associated with adverse events (heart failure and cardiovascular death). In addition, only LV GLS and LV GLS at the epicardium displayed stronger prognostic power for adverse events after adjusting for clinical and echocardiographic parameters. Furthermore, only LV GLS at the epicardium remained independently associated with cardiac death.
Similar to our study, both Hamada et al26 and Skaarup et al7 report a gradient over the LV myocardial wall with a decrease from the endocardium to the epicardium. However, our study provides additional evidence in a relatively large homogenous STEMI population treated according current guidelines.27,28 Similar to the study by Skaarup et al,7 we report that both LV GLS measured at midmyocardium and at the epicardium are associated with mortality. However, on multivariable analysis, only LV GLS at the epicardium remained associated with all-cause mortality (suggestion more transmural scar formation). Interestingly, it has been suggested that a layer-specific analysis may aid to discriminate between transmural vs subendocardial infarction. As the endocardium plays an important role in discriminating non-infarcted areas from non- transmural areas, the epicardium discriminates better between the non-transmural areas and transmural areas.29 Whereas the LV endocardial orientated fibers are primarily affected in ischemic heart disease and largely responsible for the longitudinal function,5 the mid-myocardium and the epicardial layer mostly contribute to thickening and to radial and circumferential LV systolic function. Therefore, more preserved mid- myocardium and epicardial layers appear to prevent further LV deterioration, as they reflect the extent of affected LV myocardial tissue.30,31
Several limitations should be acknowledged. The current study was retrospective in nature and all data were generated from a single centre. Furthermore, we have not examined any alteration in medical management during follow up. Finally, the measurements of layer-specific LV GLS may not be generalizable for all vendors and the cut-off value of layer-specific LV GLS provided in this study may not be applicable in other study populations.
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