title: Mechanical cavopulmonary assist maintains pulmonary and cerebral blood flow in a piglet model of a bidirectional cavopulmonary shunt with high pulmonary vascular resistance.
abstract: OBJECTIVE
  We tested mechanical cavopulmonary blood flow assist by incorporating a novel miniature centrifugal pump into a 1(1/2)-ventricle type cavopulmonary connection in neonatal pigs.
  
  
  METHODS
  Nine 3-week-old piglets (mean body weight, 10.2 kg) were used: mechanical cavopulmonary assist (n = 6) and controls (n = 3). A bidirectional cavopulmonary connection between the superior vena cava and the main pulmonary artery was created. The superior vena cava and pulmonary artery were also connected by cannulas with an interposed centrifugal pump. The cavoarterial mechanical cavopulmonary assist was performed at pump speeds of 1500, 2000, 2500, and 3000 rpm. Retrograde superior vena caval flow was limited by a band on the superior vena cava. A bidirectional cavopulmonary connection was created in the control animals, which then had a pure 1(1/2)-ventricle repair physiology without mechanical support. Hemodynamics, blood gas, and cerebral blood flow measured by ultrasound were analyzed. Catheter-based dilatation of the surgically created superior vena cava obstruction was tested.
  
  
  RESULTS
  Incremental increases in pump speed augmented bidirectional cavopulmonary shunt blood flow (P =.03) and diminished superior vena caval pressure (P =.03), thereby improving cerebral perfusion pressure. Pump flow of 3000 rpm was equivalent to baseline superior vena caval flow (before caval flow, 392 +/- 48 mL/min vs MCPA, 371 +/- 120 mL/min; mean +/- SD; P = not significant). The mechanical cavopulmonary assist group had higher Doppler velocities of the middle cerebral artery and higher transcerebral oxygen difference(P < .05) than controls. Balloon dilatation of the superior vena cava band was successful.
  
  
  CONCLUSIONS
  Mechanical cavopulmonary assist maintained bidirectional cavopulmonary shunt flow, thereby sustaining primary bilateral cavopulmonary shunt physiology in a neonatal pig model of high pulmonary vascular resistance. The mechanical cavopulmonary assist maintained cerebral blood flow and metabolism with an adequate transcerebral pressure gradient.
authors.affiliation: The Labatt Family Heart Centre, Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada.
authors.forename: Osami
authors.initials: O
authors.lastname: Honjo
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Merklinger
authors.forename: John B
authors.initials: JB
authors.lastname: Poe
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Guerguerian
authors.forename: Abdullah A
authors.initials: AA
authors.lastname: Alghamdi
authors.forename: Setsuo
authors.initials: S
authors.lastname: Takatani
authors.forename: Glen S
authors.initials: GS
authors.lastname: Van Arsdell
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001784:Blood Gas Analysis; D001921:Brain / Q000098:blood supply; D002498:Centrifugation; D002560:Cerebrovascular Circulation; D018610:Heart Bypass, Right / Q000379:methods*; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000502:physiology; D008904:Miniaturization; D023421:Models, Animal; D008955:Models, Cardiovascular; D012039:Regional Blood Flow; D013552:Swine; D018608:Ultrasonography, Doppler; D014655:Vascular Resistance; D014683:Vena Cava, Superior / Q000601:surgery; D012122:Ventilators, Mechanical