Factors Associated with Low Flow in Aortic Valve Stenosis

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.