title: Quantification of collateral aortopulmonary flow in patients subsequent to construction of bidirectional cavopulmonary shunts.
abstract: OBJECTIVE
  We sought to provide a new method for quantifying collateral aortopulmonary flow in patients subsequent to construction of a bidirectional cavopulmonary shunt, and to clarify the clinical advantages of the new method.
  
  
  METHODS
  We performed lung perfusion scintigraphy and cardiac catheterization in 10 patients subsequent to construction of a bidirectional cavopulmonary shunt. First, the ratio of collateral to systemic flow was determined by whole-body images of lung perfusion scintigraphy, dividing the total lung count by the total body count minus the total lung count. Second, we integrated lung perfusion scintigraphy and cardiac catheterization data using a formula derived from the Fick principle, taking the ratio of pulmonary to systemic flow to be 1 plus the ratio calculated above and multiplied by the systemic saturation minus the inferior caval venous saturation divided by the pulmonary venous saturation minus the inferior caval venous saturation. Finally, the amount of collateral flow was obtained from the ratio of pulmonary to systemic flow. We evaluated the impact of collateral flow on the calculation of pulmonary vascular resistance.
  
  
  RESULTS
  The median age at bidirectional cavopulmonary shunt was 1.41 years, and the median age at catheterization was 2.33 years. The mean amount of collateral flow was 1.75 +/- 0.46 litres/min/m(2). The pulmonary vascular resistance calculated without considering the collateral flow was overestimated by an average of 57 +/- 23%, compared to the resistance calculated with our new method.
  
  
  CONCLUSIONS
  The use of scintigraphy combined with catheterization allows accurate determination of aortopulmonary collateral flow, and avoids overestimation of pulmonary vascular resistance in these candidates for the Fontan circulation.
authors.affiliation: The Department of Pediatric Cardiology and Pediatric Cardiothoracic Surgery, Chiba Children's Hospital, Chiba, Japan. inuzukar-tky@umin.ac.jp
authors.forename: Ryo
authors.initials: R
authors.lastname: Inuzuka
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Aotsuka
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Nakajima
authors.forename: Hirokuni
authors.initials: H
authors.lastname: Yamazawa
authors.forename: Kenji
authors.initials: K
authors.lastname: Sugamoto
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Tatebe
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Aoki
authors.forename: Tadashi
authors.initials: T
authors.lastname: Fujiwara
mesh_terms: D000293:Adolescent; D001013:Aorta, Thoracic / Q000503:physiopathology*; D001783:Blood Flow Velocity / Q000502:physiology*; D006328:Cardiac Catheterization; D002648:Child; D002675:Child, Preschool; D003097:Collateral Circulation / Q000502:physiology*; D018610:Heart Bypass, Right / Q000379:methods*; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006352:Heart Ventricles / Q000002:abnormalities*; D006801:Humans; D007223:Infant; D011379:Prognosis; D011651:Pulmonary Artery / Q000503:physiopathology*; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D014655:Vascular Resistance / Q000502:physiology