Outcome of patients with low-flow/low-gradient severe aortic stenosis who underwent aortic valve replacement

Abstract

Background: It is well-documented that stroke volume and gradient are indexed to classify patients with aortic stenosis into several phenotypes. The purpose of the present study was to estimate the impact of stroke volume and gradient on the clinical outcome of patients with AS who have undergone aortic valve replacement. Methods: A total of 154 consecutive patients were studied. They all had severe aortic stenosis (aortic valve area [AVA] ≤ 1 cm2, left ventricular ejection fraction [LVEF] ≥ 50%) and underwent aortic valve replacement (AVR) from January 1, 2004 to December 31, 2010. Clinical and echocardiography data was collected. According to stroke volume index (SVi), low flow (LF, SVi < 35 mL/m2) and normal flow (NF, SVi ≥ 35 mL/m2) were defined, and according to transvalvular pressure gradient, low gradient (LG, gradient < 40 mmHg) and high gradient (HG, gradient ≥ 40 mmHg) were also defined. Based on the above classification, patients were separated into four groups: NF/HG (59 patients), NF/LG (30 patients), LF/HG (40 patients) and LF/LG (25 patients). To estimate the discrepancy between patients with bicuspid aortic valve (BAV) and normal 3-leaflets aortic valve, 154 cases were divided into 2 groups: BAV group and 3-leaflets group. In-hospital mortality and overall survival were followed up. The risk factors of in-hospital mortality and overall survival were estimated by logistic regression analysis and Cox regression analysis. Results: The mean follow-up time was 59 ± 32 months of 154 patients among whom the in-hospital mortality of NF/HG was 1.7% compared with NF/LG (6.7%), LF/HG (12.5%) and LF/LG (10.5%). The overall survival rates among the four groups were NF/HG (72%), NF/LG (92%), LF/HG (55%) and LF/LG (84%). The 5-year survival rate was lower in the BAV group than in the 3-leaflets group (78% and 93%; P