title: Superior hydrodynamics of a modified cavopulmonary connection for the Norwood operation.
abstract: BACKGROUND
  In the Fontan circulation, energy consumption at the cavopulmonary connection is crucial. Our hypothesis was that a modification of the standard Norwood variant of cavopulmonary connection with an extended anastomosis would improve hydrodynamics.
  
  
  METHODS
  The in vitro hydrodynamics of two different Perspex glass models resembling the Norwood variant of cavopulmonary connection (model I) and the modification (model II) were analyzed in a mock circulation at nonpulsatile flows of 2 to 5 L/min to simulate rest and exercise. The pulmonary flow split was varied to imitate varying lung resistances. Inferior-to-superior caval flow ratio and size of models were increased to simulate growth.
  
  
  RESULTS
  The pulmonary flow was preferentially directed to the left lung in model I and was better balanced in model II. Power losses increased exponentially with total flow in both models and were markedly higher in model I. These differences were attenuated in the larger models. Anastomotic turbulences were larger in model I. Power losses in both models were relatively insensitive to changes in pulmonary flow split.
  
  
  CONCLUSIONS
  The proposed modification of the Norwood variant of cavopulmonary connection seems to be hydrodynamically advantageous and warrants further evaluation.
authors.affiliation: Department of Cardiac Surgery, Medical University of Lübeck, Germany. herzchir@medinf.mu-luebeck.de
authors.forename: H H
authors.initials: HH
authors.lastname: Sievers
authors.forename: A
authors.initials: A
authors.lastname: Gerdes
authors.forename: J
authors.initials: J
authors.lastname: Kunze
authors.forename: G
authors.initials: G
authors.lastname: Pfister
mesh_terms: D000714:Anastomosis, Surgical / Q000379:methods*; D004734:Energy Metabolism; D018729:Fontan Procedure; D018056:Hemorheology; D006801:Humans; D018636:Hypoplastic Left Heart Syndrome / Q000503:physiopathology / Q000601:surgery*; D008953:Models, Anatomic; D008955:Models, Cardiovascular; D005082:Physical Exertion / Q000502:physiology; D019904:Polymethyl Methacrylate; D011651:Pulmonary Artery / Q000254:growth & development / Q000601:surgery*; D011652:Pulmonary Circulation / Q000502:physiology; D012039:Regional Blood Flow / Q000502:physiology; D012146:Rest / Q000502:physiology; D014655:Vascular Resistance / Q000502:physiology; D014682:Vena Cava, Inferior / Q000502:physiology; D014683:Vena Cava, Superior / Q000254:growth & development / Q000601:surgery*
chemical_list: D019904:Polymethyl Methacrylate