Low-Gradient “Severe” Aortic Stenosis With Normal Systolic Function

Abstract

Aortic stenosis (AS) is a progressive valvular disease that carries significant morbidity and mortality when hemodynamically significant. Traditionally, in normal-flow conditions, AS has been defined as severe when the transvalvular pressure gradient is >50 mm Hg and the effective aortic valve area (AVA) is significantly reduced. Some patients, however, manifest a restricted AVA but have a paradoxically low pressure gradient with a normal ejection fraction (EF). Low-gradient “severe” AS (LGSAS) with preserved left ventricular EF (LVEF) remains not well understood but has been thought to portend a very poor prognosis on the basis of recent retrospective studies.1,2 A new study by Jander et al3 in the current issue of Circulation sheds further light on this entity and has considerable implications for not only the prognosis of patients with LGSAS but also for how we define severe AS. Article see p 887 The study by Jander et al3 evaluated a large number of patients (n=1525) with asymptomatic AS in the prospective Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study, with peak transaortic velocity by Doppler between 2.5 and 4 m/s and a LVEF ≥55%. Of these, 12% (n=184) had moderate stenosis (AVA: 1 to 1.5 cm2) and 29% (n=435) had low-gradient “severe” stenosis (valve area <1.0 cm2 and mean gradient ≤40 mm Hg); the remaining majority had mild stenosis. The moderate AS group had higher flow with slightly higher mean gradient than the LGSAS group (31 versus 26 mm Hg), with a larger valve area (1.19 versus 0.82 cm2). Patients with LGSAS were older, had smaller body habitus, were more often women, had slightly higher blood pressure, and had smaller ventricles at end diastole but with similar EF. It is noteworthy that, in this study, patients with LGSAS had normal LV mass (99±31 …