Page 48 - The role of advanced echocardiography in patients with ischemic heart disease - Rachid Abou

Chapter two. Level and Layer Specific Left Ventricular Longitudinal Strain
and regional LV dysfunction.16,17 Previous study reported the layer-specific values of longitudinal strain in a single center study including 119 healthy volunteers (age range, 22-76 years; 50% women).10 A gradient from the endocardium to the epicardium was observed with the highest magnitude of longitudinal strain in the endocardial layer (-24.3 ± 3.1%) and the lowest in the epicardial layer (-18.9 ± 2.8%). Compared to men, women showed slightly more preserved values of longitudinal strain at all the layers. Similar to our study, aging did not influence significantly on layer-specific longitudinal strain values.
Several factors may influence global LV longitudinal strain in individuals without structural heart disease. Diabetes and hypertension for example have been associated with impaired global LV longitudinal strain.18,19 However, little is known about the correlates of LV layer-specific global longitudinal strain. Other studies have shown that hypertension has an important influence on layer-specific longitudinal strain. In 145 patients with hypertension and preserved LVEF, Kim et al showed that longitudinal strain was significantly reduced (less negative) in all the myocardial layers compared with 31 normotensive controls.20 Importantly, LV mass was a strongly associated with layer-specific longitudinal strain and those patients with larger LV mass showed more impaired longitudinal strain across all the myocardial layers. The present study showed that diabetes was associated with impaired longitudinal strain of the endocardial layer. This is line with previous studies showing that the endocardium is most susceptible to early injury caused by diabetes.21,22 In addition, impaired longitudinal strain of the endocardial layer has been associated with cardiovascular events in patients with coronary artery disease.16,23 Whether this may be extended to patients with cardiovascular risk factors needs further research.
Several limitations should be acknowledged. The current study was retrospective and included patients without structural heart disease but a significantly proportion who had cardiovascular risk factors or used cardiovascular medication that may influence LV mechanics. Therefore, the values of level- and layer-specific longitudinal strain reported in this article may not be generalizable. Blood pressure values in patients with hypertension and extent of disease activity in patients with diabetes mellitus were not systematically available. Furthermore, LV strain measurements were performed with dedicated post-processing software, and the values obtained with this specific software may not be generalised to other vendors.
In conclusion, with increasing age, the magnitude of LV longitudinal strain at the basal level declines while the apical LV longitudinal strain increases. In contrast, layer-
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