Relative Contribution of Afterload and Interstitial Fibrosis to Myocardial Function in Severe Aortic Stenosis.
(2020) JACC : Cardiovascular Imaging — Vol. 13, n° 2 Pt 2, p. 589-600 (2020)
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Vanoverschelde, Jean-Louis 
- Abstract
- (en) OBJECTIVES: The present study aimed at investigating the respective contribution of afterload and myocardial fibrosis to pre- and post-operative left ventricular (LV) function by using stress-strain relationships. BACKGROUND: Separating the effect of myocardial dysfunction and afterload on pump performance has important implications for the prognosis and management of patients with severe aortic stenosis (AS). METHODS: A total of 101 patients with isolated severe AS (57% men; mean age 71 years) and 75 healthy control subjects underwent resting 2-dimensional and speckle-tracking echocardiography to measure global circumferential strain (GCS) and global longitudinal strain (GLS), as well as end-systolic wall stress (ESWS). Normal stress-strain relationships were constructed using control subjects' data and fitted to linear regression. End-systolic stress-strain indexes (the number of SDs from the mean regression line) were used as an afterload-independent index of myocardial function and compared with myocardial fibrosis, measured on transmural myocardial biopsies harvested at the time of surgery. RESULTS: GCS and GLS were afterload-dependent in both control subjects and patients. The GLS-ESWS relationship of patients was shifted downward compared with control subjects. Patients with reduced pre-operative end-systolic stress-strain indexes exhibited larger degrees of interstitial myocardial fibrosis than patients without (3.8 ± 2.9% vs. 8.3 ± 6.3%, p < 0.001; and 4.9 ± 4.4% vs. 9.5 ± 6.4%; p < 0.001, for GLS and GCS, respectively). By multivariate analysis, pre-operative end-systolic stress-strain indexes were the only predictors of post-operative longitudinal and circumferential end-systolic stress-strain indexes (ß = 0.49 and ß = 0.60, respectively; p < 0.001). CONCLUSIONS: Myocardial strains are afterload-dependent. In patients with severe AS, pre-operative stress-strain indexes allow identification of patients with increased myocardial fibrosis and predict the extent of functional recovery after aortic valve replacement.
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Slimani, A., Melchior, J., de Meester de Ravenstein, C., Pierard, S., Roy, C., Amzulescu, M., Bouzin, C., Maes, F., Pasquet, A., Pouleur, A.-C., Vancraeynest, D., Gerber, B., El Khoury, G., & Vanoverschelde, J.-L. (2020). Relative Contribution of Afterload and Interstitial Fibrosis to Myocardial Function in Severe Aortic Stenosis. JACC : Cardiovascular Imaging, 13(2 Pt 2), 589-600. https://doi.org/10.1016/j.jcmg.2019.05.020 (Original work published 2020)