title: Influence of Left Ventricular Stiffness on Hemodynamics in Patients With Untreated Atrial Septal Defects.
abstract: BACKGROUND
  Although left ventricular (LV) stiffening with age is believed to increase left-to-right shunting in patients with atrial septal defects (ASD), clinical data have not confirmed this. We sought determinants of the pulmonary-to-systemic flow ratio (Qp/Qs) in patients with untreated ASD.
  
  
  RESULTS
  We retrospectively studied 180 patients with ASD who underwent percutaneous ASD closure between 2007 and 2011. Qp/Qs and LV stiffness were measured before ASD closure.The median age of the subjects was 18 years, and 117 (65.0%) were female. The mean ASD size adjusted for square root of body surface area (BSA) was 14.4±4.2 mm/m, and the Qp/Qs was 2.28±0.74. Adjusted ASD size most strongly related to Qp/Qs (r=0.74, P<0.0001). Multivariate analysis revealed that LV stiffness was a significant predictor of Qp/Qs, independently of adjusted ASD size and vascular resistance (P=0.0015). Based on the multivariate model that accounts for the effects of LV stiffness and vascular resistance, the minimal adjusted diameter that can cause a Qp/Qs of 2.0 was predicted to be 7.3 mm/m.
  
  
  CONCLUSIONS
  Qp/Qs in ASD can change significantly depending on LV stiffness, suggesting that it would increase with age. An ASD >7.3 mm/m in diameter has the potential to cause significant left-to-right shunting, and may require closure regardless of hemodynamic status at the time of assessment.
authors.affiliation: Division of Pediatric Cardiology, Saitama Medical University.
authors.forename: Clara
authors.initials: C
authors.lastname: Kurishima
authors.forename: Ryo
authors.initials: R
authors.lastname: Inuzuka
authors.forename: Seiko
authors.initials: S
authors.lastname: Kuwata
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Iwamoto
authors.forename: Masaya
authors.initials: M
authors.lastname: Sugimoto
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Saiki
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Ishido
authors.forename: Satoshi
authors.initials: S
authors.lastname: Masutani
authors.forename: Hideaki
authors.initials: H
authors.lastname: Senzaki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006343:Heart Septal Defects / Q000503:physiopathology*; D006352:Heart Ventricles; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D014655:Vascular Resistance