title: Aortopulmonary collateral flow is related to pulmonary artery size and affects ventricular dimensions in patients after the fontan procedure.
abstract: BACKGROUND
  Aortopulmonary collaterals (APCs) are frequently found in patients with a single-ventricle (SV) circulation. However, knowledge about the clinical significance of the systemic-to-pulmonary shunt flow in patients after the modified Fontan procedure and its potential causes is limited. Accordingly, the aim of our study was to detect and quantify APC flow using cardiovascular magnetic resonance (CMR) and assess its impact on SV volume and function as well as to evaluate the role of the size of the pulmonary arteries in regard to the development of APCs.
  
  
  METHODS
  60 patients (mean age 13.3 ± 6.8 years) after the Fontan procedure without patent tunnel fenestration underwent CMR as part of their routine clinical assessment that included ventricular functional analysis and flow measurements in the inferior vena cava (IVC), superior vena cava (SVC) and ascending aorta (Ao). APC flow was quantified using the systemic flow estimator: (Ao) - (IVC + SVC). Pulmonary artery index (Nakata index) was calculated as RPA + LPA area/body surface area using contrast enhanced MR angiography. The patient cohort was divided into two groups according to the median APC flow: group 1 < 0.495 l/min/m(2) and group 2 > 0.495 l/min/m(2).
  
  
  RESULTS
  Group 1 patients had significant smaller SV enddiastolic (71 ± 16 vs 87 ± 25 ml/m(2); p=0.004) and endsystolic volumes (29 ± 11 vs 40 ± 21 ml/m(2); p=0.02) whereas ejection fraction (59 ± 9 vs 56 ± 13%; p=0.38) differed not significantly. Interestingly, pulmonary artery size showed a significant inverse correlation with APC flow (r=-0.50, p=0.002).
  
  
  CONCLUSIONS
  Volume load due to APC flow in Fontan patients affected SV dimensions, but did not result in an impairment of SV function. APC flow was related to small pulmonary artery size, suggesting that small pulmonary arteries represent a potential stimulus for the development of APCs.
authors.affiliation: Pediatric Heart Center, Justus-Liebig University Clinic, Giessen, Germany.
authors.forename: Heiner
authors.initials: H
authors.lastname: Latus
authors.forename: Kerstin
authors.initials: K
authors.lastname: Gummel
authors.forename: Tristan
authors.initials: T
authors.lastname: Diederichs
authors.forename: Anna
authors.initials: A
authors.lastname: Bauer
authors.forename: Stefan
authors.initials: S
authors.lastname: Rupp
authors.forename: Gunter
authors.initials: G
authors.lastname: Kerst
authors.forename: Christian
authors.initials: C
authors.lastname: Jux
authors.forename: Hakan
authors.initials: H
authors.lastname: Akintuerk
authors.forename: Dietmar
authors.initials: D
authors.lastname: Schranz
authors.forename: Christian
authors.initials: C
authors.lastname: Apitz
mesh_terms: D000293:Adolescent; D002648:Child; D003097:Collateral Circulation; D005260:Female; D018729:Fontan Procedure; D006352:Heart Ventricles / Q000033:anatomy & histology* / Q000503:physiopathology*; D006801:Humans; D018810:Magnetic Resonance Angiography; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D011651:Pulmonary Artery / Q000033:anatomy & histology* / Q000503:physiopathology*; D011652:Pulmonary Circulation; D012039:Regional Blood Flow