Abstract
Background: Risk stratification of normal-flow, low-gradient (NFLG) severe aortic stenosis (SAS) with preserved left ventricular (LV) ejection fraction (EF) remains unclear. Methods and Results: Of 289 consecutive patients diagnosed with SAS by aortic valve area <1.0 cm(2), 66 with NFLG-SAS (stroke volume index >35 mL/m(2), mean pressure gradient <40 mmHg, LVEF ≥50%) were enrolled in this study; patients with bicuspid aortic valve, acute coronary syndrome, hemodialysis, or a history of aortic valve replacement (AVR) were excluded. Adverse events (AEs) were defined as cardiovascular death, hospitalization for heart failure, and deteriorating condition requiring AVR. Factors associated with AEs were investigated using a Cox proportional hazards model. Over a median of 675 days of follow-up, 25 AEs were recorded: 4 cardiovascular deaths, 12 hospitalizations for heart failure, and 9 patients requiring AVR. In addition, there were 14 events of progression to high-gradient SAS. Multivariable analysis showed significant associations between AEs and the presence of symptoms (hazard ratio [HR] 10.276; 95% confidence interval [CI] 3.724-28.357; P<0.001), LV hypertrophy (LV mass index >115 and >95 mg/m(2) for males and females, respectively; HR 3.257; 95% CI 1.172-9.050; P=0.024), and tricuspid regurgitation (TR) velocity (HR 2.761; 95% CI 1.246-6.118; P=0.012). Conclusions: The presence of symptoms, LV hypertrophy, and high TR velocity could be reliable prognostic indicators and may require watchful waiting for timely AVR in patients with NFLG-SAS.