Association between Left Atrial Dilatation and Invasive Hemodynamics at Rest and during Exercise in Asymptomatic Aortic Stenosis

Abstract

Background - Transition from an asymptomatic to symptomatic state in severe aortic stenosis is often difficult to assess. Identification of a morphological sign of increased hemodynamic load may be important in asymptomatic aortic stenosis to identify patients at risk. Methods and Results - Thirty-nine patients with asymptomatic severe aortic stenosis (aortic valve area <1 cm 2, peak jet velocity >3.5 m/s) underwent exercise testing with simultaneous invasive hemodynamic monitoring and Doppler echocardiography. Cardiac index, pulmonary artery pressure, and pulmonary capillary wedge pressure (PCWP) were recorded. Patients were followed up for the composite end point of death, unplanned hospitalization, or aortic valve replacement. Patients were stratified into 2 groups according to left atrial (LA) volume index ≥35 mL/m 2. In 25 patients (64%) LA volume index was ≥35 mL/m 2. Aortic valve area was similar between groups (0.81±0.15 versus 0.84±0.18 cm 2; P=0.58). PCWP was higher at rest and during exercise in patients with LA volume index ≥35 mL/m 2 (P<0.01), despite similar cardiac index. At rest, PCWP was <12 mm Hg in 11 patients (44%) with LA dilatation, whereas PCWP was <25 mm Hg in 1 patient (4%) with exercise. LA volume index and E/e′ predicted exercise PCWP>30 mm Hg with areas under the receiver operating curve of 0.75 and 0.84, respectively. During follow-up, 14 cardiac events were recorded. LA volume was associated with a hazard ratio of 1.90 (95% confidence interval, 0.92-4.15). Conclusions - LA size reflects hemodynamic burden in patients with asymptomatic severe aortic stenosis. Quantitative measurements of LA and diastolic function are associated with left ventricular filling pressures with exercise and could be used to identify asymptomatic patients with increased hemodynamic burden. Clinical Trial Registration - URL: http://www.clinicaltrials.gov. Unique identifier: NCT02395107.