Impact of Afterload Increase on Left Ventricular Myocardial Deformation Indices

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• 作者：Patricia Reant ; MD ; PhD^a ; ^b ; ^c ; ^d ; ^{patricia.reant@chu-bordeaux.fr} ; Alexandre Metras ; MD^b ; ^c ; ^e ; Dominique Detaille ; PhD^a ; ^d ; Annabel Reynaud ; PhD^e ; Philippe Diolez ; PhD^a ; ^d ; Beatrice Jaspard-Vinassa ; PhD^b ; ^e ; Raymond Roudaut ; MD^b ; ^c ; Alexandre Ouattara ; MD ; PhD^b ; ^e ; ^f ; Laurent Barandon ; MD ; PhD^b ; ^c ; ^e ; Pierre Dos Santos ; MD ; PhD^a ; ^b ; ^c ; ^d ; Stephane Lafitte ; MD ; PhD^b ; ^c ; ^d ; ^e
• 关键词：Animal model ; Aortic stenosis ; Left ventricular afterload ; Echocardiography ; Left ventricular hypertrophy ; Myocardial strain
• 刊名：Journal of the American Society of Echocardiography
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：29
• 期：12
• 页码：1217-1228
• 全文大小：1454 K
• 卷排序：29

文摘

Left ventricular (LV) afterload could be associated with reduced myocardial contractility. The aim of this study was to evaluate the relative impact of increased afterload on LV myocardial deformation indices in chronic aortic constriction, with regard to hypertrophy, myocardial fibrosis, and mitochondrial function, and to differentiate acute versus chronic afterload effect.MethodsYoung pigs underwent aortic banding (n = 11) or sham (n = 7) operations. Nineteen weeks later, LV morphology and systolic function, including myocardial deformation, were assessed by echocardiography before and after banding release or acute aortic constriction (in the sham group). After the animals were euthanized, mitochondrial function and LV interstitial fibrosis were assessed.ResultsThe chronic banding group (n = 8) presented with significant LV hypertrophy compared with the sham group (n = 7), and longitudinal strain (LS) was significantly altered (16.9 ± 0.7% vs 20.3 ± 0.7%, P = .001) while circumferential, radial strain, and ejection fraction were not. LS abnormalities were situated mostly on the basal and mid segments and on the septal wall. There was also significantly more myocardial fibrosis in the chronic banding group compared with the sham group, while mitochondrial function was preserved. The relative contributions of hypertrophic and fibrotic remodeling and of afterload to alter global LS were 62%, and 38%, respectively. Acute aortic banding also significantly altered LS. The ratio of LS to septal wall thickness enabled differentiation between chronic and acute afterload increase (1.9 ± 0.2 in the chronic group vs 2.9 ± 0.3 in the acute group, P = .001).ConclusionsLS is susceptible to both hypertrophic and fibrotic remodeling and afterload increase, particularly on the basal and mid LV segments of the septum. The ratio of LS to septal wall thickness enables differentiation of acute from chronic afterload LS alteration.