Relation of Left Atrial Size, Cardiac Morphology, and Clinical Outcome in Asymptomatic Aortic Stenosis

Abstract

Left atrial (LA) dilation in asymptomatic severe aortic stenosis (AS) may be an indicator of advanced disease. We aimed to investigate the association between LA volume index and left ventricular (LV) morphology assessed with cardiac magnetic resonance imaging (cMRI), and to assess the association with cardiac events. Ninety-two asymptomatic patients with aortic valve area <1 cm2, aortic peak jet velocity >3.5 m/s, and ejection fraction ≥50% were prospectively enrolled and divided according to echocardiographic-derived LA volume index <35 ml/m2. Patients underwent echocardiography, cMRI, exercise testing, and were followed for the composite end point of death, readmission, or aortic valve replacement. Aortic valve area index was similar (0.45 ± 0.08 cm2/m2 vs 0.45 ± 0.09 cm2/m2, p = 0.85) in patients with a dilated and normal LA. On cMRI patients with dilated LA were characterized by higher LV mass index (73 ± 17 g/m2 vs 66 ± 16 g/m2, p = 0.03), increased right ventricle (70 ± 14 ml/m2 vs 63 ± 12 ml/m2, p = 0.01) and LV end-diastolic volume index (84 ± 18 ml/m2 vs 77 ± 16 ml/m2, p = 0.05), and higher brain natriuretic peptide. Late enhancement pattern was similar. During follow-up 20 events were recorded in patients with LA dilation compared with 8 in patients with normal LA (adjusted hazard ratio 2.77, 95% confidence interval 1.19 to 6.46, p = 0.02); also B-type natriuretic peptide >125 pg/ml was associated with adverse outcome (adjusted hazard ratio 3.63, 95% confidence interval interval 1.28 to 10.32, p = 0.02). LA dilation is associated with LV remodeling and provides prognostic information in severe asymptomatic AS.