Outcome and Impact of Aortic Valve Replacement in Patients with Preserved LVEF and Low-Gradient Aortic Stenosis

Abstract

Background Low mean transvalvular gradient (<40 mm Hg) and small aortic valve area (<1.0 cm2) in patients with aortic stenosis (AS) and preserved left ventricular ejection fraction raises uncertainty about the actual severity of the stenosis and survival benefit of aortic valve replacement (AVR). Objectives This study analyzed studies of mortality and survival impact of AVR in patients with low-gradient (LG) AS and preserved left ventricular ejection fraction, including paradoxical low-flow (i.e., stroke volume index <35 ml/m2), low-gradient (LF-LG) and normal-flow, low-gradient (NF-LG), and those with high-gradient (≥40 mm Hg) AS or moderate AS. Methods Studies published between 2005 and 2015 were analyzed. Primary outcome was the survival benefit associated with AVR. Secondary outcome was overall mortality regardless of treatment. Results Eighteen studies were included in the analysis. Patients with LF-LG AS have increased mortality compared with patients with moderate AS (hazard ratio [HR]: 1.68; 95% confidence interval [CI]: 1.31 to 2.17), NF-LG (HR: 1.80; 95% CI: 1.29 to 2.51), and high-gradient (HR: 1.67; 95% CI: 1.16 to 2.39) AS. AVR was associated with reduced mortality in patients with LF-LG (HR: 0.44; 95% CI: 0.25 to 0.77). Similar benefit occurred with AVR in patients with NF-LG (HR: 0.48; 95% CI: 0.28 to 0.83). Compared with patients with high-gradient AS, those with LF-LG were less likely to be referred to AVR (odds ratio: 0.32; 95% CI: 0.21 to 0.49). Conclusions Patients with paradoxical LF-LG AS and NF-LG AS have increased risk of mortality compared with other subtypes of AS with preserved left ventricular ejection fraction, and improved outcome with AVR.