title: Prognostic utility of right atrial emptying fractions in pulmonary arterial hypertension.
abstract: Although left atrial function has been extensively studied in patients with heart failure, the determinants and clinical correlates of impaired right atrial (RA) function have been poorly studied. We investigated measures of RA function in pulmonary arterial hypertension (PAH). We identified all treatment-naive patients with World Health Organization category 1 PAH seen at our center during 2000-2011 who had right heart catheterization and 6-minute walk test (6MWT) within 1 month of initial echocardiographic examination. Atrial size was measured using the monoplane area-length method, and atrial function was quantified using total, passive, and active RA emptying fractions (RAEFs). We compared measures of RAEF with known prognostic clinical, echocardiographic, and hemodynamic parameters. For the subset of patients with follow-up echocardiographic examination/6MWT within 6-18 months, we investigated the change in RAEF. In an exploratory analysis, we investigated the association between RAEF and mortality. Our population consisted of 39 patients with treatment-naive (incident) PAH, 30 of whom had follow-up testing. The mean total, passive, and active RAEFs were 24.4% ± 15.1%, 8.5% ± 6.9%, and 17.6% ± 13.9%, respectively. Total and active RAEFs correlated with tricuspid annular plane systolic excursion (P = 0.004 and P = 0.005) and cardiac output (P = 0.02 and P = 0.01). The change in active RAEF correlated with change in 6-minute walk distance (P = 0.02). In our Cox regression analysis, low active and total RAEF were associated with mortality, with hazard ratios of 5.6 (95% confidence interval [CI], 1.2-26.2; P = 0.03) and 4.2 (95% CI, 1.1-15.5; P = 0.03), respectively. Passive RAEF was poorly reproducible and not associated with outcome. Measures of RAEF appear to have prognostic importance in PAH and warrant further study.
authors.affiliation: Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, California, USA ; Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Nathan W
authors.initials: NW
authors.lastname: Brunner
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Francois
authors.initials: F
authors.lastname: Haddad
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Hsi
authors.affiliation: Division of Respirology, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: John R
authors.initials: JR
authors.lastname: Swiston
authors.affiliation: Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Kenneth G
authors.initials: KG
authors.lastname: Gin
authors.affiliation: Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, California, USA ; Division of Pulmonary and Critical Care Medicine, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Roham T
authors.initials: RT
authors.lastname: Zamanian
keywords: echocardiography; prognosis; pulmonary arterial hypertension; right atrial emptying fraction