title: Left Atrium Maximal Axial Cross-Sectional Area is a Specific Computed Tomographic Imaging Biomarker of World Health Organization Group 2 Pulmonary Hypertension.
abstract: OBJECTIVE
  Left heart disease is associated with left atrial enlargement and is a common cause of pulmonary hypertension (PH). We investigated the relationship between left atrium maximal axial cross-sectional area (LA-MACSA), as measured on chest computed tomography (CT), and PH due to left heart disease (World Health Organization group 2) in patients with right heart catheterization-proven PH.
  
  
  METHODS
  A total of 165 patients with PH who had undergone right heart catheterization with pulmonary artery pressure and pulmonary capillary wedge pressure (PCWP) measurements and nongated chest CTs were included. LA-MACSA, LA anterior-posterior, and LA transverse measurements were independently obtained using the hand-drawn region-of-interest and distance measurement tools on standard PACS by 2 blinded cardiothoracic radiologists. Nonparametric statistical analyses and receiver operating characteristic curve were performed.
  
  
  RESULTS
  Forty-three patients had group 2 PH (PCWP>15 mm Hg), and 122 had nongroup 2 PH (PCWP≤15 mm Hg). Median LA-MACSA was significantly different between the group 2 PH and nongroup 2 PH patients (2312 vs. 1762 mm, P<0.001). Interobserver concordance correlation for LA-MACSA was high at 0.91 (P<0.001). At a threshold of 2400 mm, LA-MACSA demonstrated 93% specificity for classifying group 2 PH (area under the curve, 0.73; P<0.001).
  
  
  CONCLUSIONS
  LA-MACSA is a readily obtainable and reproducible measurement of left atrial enlargement on CT and can distinguish between group 2 and nongroup 2 PH with high specificity.
authors.affiliation: *Department of Radiology †Department of Pulmonary and Critical Care Medicine §Department of Cardiovascular Medicine ∥Department of Radiology, Division of Biostatistics ‡Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford Health Care, Stanford, CA.
authors.forename: Khalil
authors.initials: K
authors.lastname: Jivraj
authors.forename: Arash
authors.initials: A
authors.lastname: Bedayat
authors.forename: Yon K
authors.initials: YK
authors.lastname: Sung
authors.forename: Roham T
authors.initials: RT
authors.lastname: Zamanian
authors.forename: Francois
authors.initials: F
authors.lastname: Haddad
authors.forename: Ann N C
authors.initials: AN
authors.lastname: Leung
authors.forename: Jarrett
authors.initials: J
authors.lastname: Rosenberg
authors.forename: H Henry
authors.initials: HH
authors.lastname: Guo
mesh_terms: D015415:Biomarkers; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014944:World Health Organization
chemical_list: D015415:Biomarkers