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Factors Associated with Low Flow in Aortic Valve Stenosis
Darryl P Leong1, Stephen Pizzale2, Michelle J Haroun2
1Department of Medicine, McMaster University, Hamilton, Ontario, Canada; Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, Ontario, Canada.
Insights
Low-flow low-gradient aortic stenosis (AS) is linked to worse outcomes. Right ventricular dysfunction and atrial fibrillation predict low flow, with mitral regurgitation also associated in patients with preserved ejection fraction.
Area of Science:
- Cardiology
- Echocardiography
- Valvular Heart Disease
Background:
- Low-flow low-gradient aortic stenosis (AS) is associated with poorer patient outcomes compared to normal-flow AS.
- While reduced left ventricular ejection fraction (LVEF) is known to cause low flow, other cardiac factors are less understood.
Purpose of the Study:
- To identify cardiac structural and functional characteristics associated with low-flow low-gradient AS.
- To investigate factors contributing to low flow in patients with AS, particularly those with preserved LVEF.
Main Methods:
- Retrospective analysis of clinical and echocardiographic data from 941 patients with native AS and valve area ≤ 1.0 cm².
- Multivariate analysis to determine independent predictors of low flow (stroke volume index < 35 mL/m²).
Main Results:
- Right ventricular systolic dysfunction, atrial fibrillation, lower LVEF, and higher left ventricular mass were independently associated with low flow.
- Moderate or severe mitral regurgitation (MR) was independently associated with low flow in 74% of patients with preserved LVEF.
Conclusions:
- Right ventricular dysfunction and atrial fibrillation are key independent predictors of low-flow low-gradient AS.
- Moderate to severe MR is a significant independent predictor of low flow in AS patients with preserved LVEF.
- Recognizing these associations is crucial for accurate AS severity assessment and appropriate management.
Background:
Low-flow low-gradient aortic stenosis (AS) is a predictor of worse outcome compared with normal-flow AS. Although depressed left ventricular ejection fraction (LVEF) is associated with low flow, there is less evidence to support the role of other indices of cardiac structure and function.
Methods:
Clinical and echocardiographic data from patients with native AS and valve areas ≤ 1.0 cm(2) were retrospectively analyzed to identify characteristics that are associated with low-flow low-gradient AS.
Results:
In total, 941 patients were included. On multivariate analysis, factors independently associated with low flow (stroke volume index < 35 mL/m(2)) included worse right ventricular systolic function, atrial fibrillation, lower LVEF, and higher left ventricular mass, with moderate or severe mitral regurgitation independently associated with low flow in the 694 patients (74%) with preserved LVEFs.
Conclusions:
Right ventricular dysfunction and atrial fibrillation are independently associated with low-flow low-gradient AS, while moderate or severe MR is independently associated with low flow in patients with preserved LVEF. These associations with low flow in AS are clinically important to recognize, to avoid underestimation of AS severity.
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