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Dobutamine stress echocardiography for management of low-flow, low-gradient aortic stenosis

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Elsevier Biomedical
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Structures organisationnelles
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Background: Dobutamine stress echocardiography (DSE) is useful to differentiate true from pseudo severe aortic stenosis in patients with low left ventricular ejection fraction (LVEF), low-flow, low-gradient aortic stenosis (LF-LG AS). In the ACC/AHA guidelines, patients are considered having true-severe stenosis when the mean gradient (MG) is ≥40mmHg with an aortic valve area (AVA) ≤1cm2 during DSE. However these criteria have not been previously validated. The aim of this study was to assess the value of these criteria to predict the presence of true-severe AS and the occurrence of death in patients with LFLG AS. Methods: In the TOPAS (“True or Pseudo-Severe Aortic Stenosis”) study, 186 patients with low LVEF LF-LG AS were prospectively recruited and underwent DSE with measurement of the MG, AVA and projected AVA, an estimate of the AVA at a standardized normal flow rate (AVAProj). Severity of AS was independently corroborated by macroscopic evaluation of the valve at the time of valve replacement in 54 patients and by measurement of the aortic valve calcium by computed tomography in 25 patients and by both methods in 8. According to these assessments, 50/87 (57%) of the study cohort had true-severe stenosis. Results: Peak stress MG ≥40 mmHg, peak stress AVA ≤1cm2, and the combination of peak stress MG ≥40 mmHg and peak stress AVA≤1cm2 correctly classified AS severity in 48%, 60%, and 47% of patients, respectively, whereas AVAProj ≤1cm2 was better than all the previous markers (p<0.007) with 70% of correct classification. Among the subset of 88 patients managed conservatively (47% of cohort), 52 died during a follow-up of 2.8±2.5 years. After adjustment for age, sex, functional capacity, chronic kidney failure and peak stress LVEF, peak stress MG and AVA were not predictors of mortality in this subset. In contrast, AVAProj ≤1cm2 was a strong predictor of mortality under medical management (HR: 3.65; p=0.0003). Conclusion: In patients with low LVEF LF-LG AS, the DSE criteria of peak stress MG≥40 mmHg, or the composite of peak stress MG≥40 mmHg and peak stress AVA≤1cm2 proposed in the guidelines to identify true-severe AS and recommend valve replacement, have limited value to predict actual stenosis severity and outcomes. In contrast, AVAProj better distinguishes true from pseudo-severe aortic stenosis and is strongly associated with mortality in patients under conservative management.
Journal of the American College of Cardiology, Vol. 71 (5), 475–485 (2018)
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Aortic stenosis , Stress echocardiography , Survival , LV dysfunction
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article de recherche