High Prevalence of Severe Aortic Stenosis in Low-Flow State Associated With Atrial Fibrillation

Abstract

Background: Atrial fibrillation (AF) is a low-flow state and may underestimate aortic stenosis (AS) severity. Single-high Doppler signals (HS) consistent with severe AS (peak velocity ≥4 m/s or mean gradient ≥40 mm Hg) are averaged down in current practice. The objective for the study was to determine the significance of HS in AF low-gradient AS (LGAS). Methods: One thousand five hundred forty-one patients with aortic valve area ≤1 cm 2 and left ventricular ejection fraction ≥50% were identified and classified as high-gradient AS (HGAS) (≥40 mm Hg) and LGAS (<40 mm Hg), and AF versus sinus rhythm (SR). Available computed tomography aortic valve calcium scores (AVCS) were retrieved from the medical record. Outcomes were assessed. Results: Mean age was 76±11 years, female 47%. Mean gradient was 51±12 in SR-HGAS, 48±10 in AF-HGAS, 31±5 in SR-LGAS, and 29±7 mm Hg in AF-LGAS, all P ≤0.001 versus SR-HGAS; HS were present in 33% of AF-LGAS. AVCS were available in 34%. Compared with SR-HGAS (2409 arbitrary units; interquartile range, 1581–3462) AVCS were higher in AF-HGAS (2991 arbitrary units; IQR1978–4229, P =0.001), not different in AF-LGAS (2399 arbitrary units; IQR1817–2810, P =0.47), and lower in SR-LGAS (1593 arbitrary units; IQR945–1832, P <0.001); AVCS in AF-LGAS were higher when HS were present ( P =0.048). Compared with SR-HGAS, the age-, sex-, comorbidity index-, and time-dependent aortic valve replacement-adjusted mortality risk was higher in AF-HGAS (hazard ratio=1.82 [1.40–2.36], P <0.001) and AF-LGAS with HS (hazard ratio=1.54 [1.04–2.26], P =0.03) but not different in AF-LGAS without HS or SR-LGAS (both P =not significant). Conclusions: Severe AS was common in AF-LGAS. AVCS in AF-LGAS were not different from SR-HGAS. AVCS were higher and mortality worse in AF-LGAS when HS were present.