Low-Gradient Severe Aortic Stenosis: Insights From the CURRENT AS Registry-2.

Background: Low-gradient (LG) aortic stenosis (AS) has not been fully characterized compared with high-gradient (HG) AS in terms of cardiac damage, frailty, aortic valve calcification, and clinical outcomes.

Objectives: The aim of this study was to compare the clinical characteristics and outcomes between each hemodynamic type of LG AS and HG AS.

Methods: The current study included 3,363 patients in the CURRENT AS (Contemporary outcomes after sURgery and medical tREatmeNT in patients with severe Aortic Stenosis) Registry-2 after excluding patients without indexed stroke volume or left ventricular ejection fraction (LVEF) data. Patients were divided into 4 groups (LG AS with reduced LVEF: n = 285; paradoxical low flow, low gradient [LFLG]: n = 220; normal flow, low gradient [NFLG]: n = 872; HG: n = 1,986).

Results: Compared with HG AS, LG AS with reduced LVEF more often had cardiovascular comorbidities, advanced cardiac damage, and frailty with less severe valve calcification and paradoxical LFLG AS more often had atrial fibrillation, advanced cardiac damage, and frailty with less severe valve calcification, while NFLG AS had comparable cardiac damage and frailty with less severe valve calcification. Cumulative 3-year incidence of death or heart failure hospitalization was higher in LG AS with reduced LVEF and paradoxical LFLG than in HG AS. After adjusting for confounders, LG AS with reduced LVEF and paradoxical LFLG compared with HG AS were independently associated with higher risk for death or heart failure hospitalization (HR: 1.82; 95% CI: 1.49-2.23; P < 0.001; and HR: 1.43; 95% CI: 1.13-1.82; P = 0.003, respectively) but NFLG AS was not (HR: 1.03; 95% CI: 0.88-1.21; P = 0.68).

Conclusions: Clinical outcomes were significantly worse in LG AS with reduced LVEF and paradoxical LFLG AS and comparable in NFLG AS compared with HG AS.