title: Experimental Evaluation of Tracheo-Amniotic Shunting for Induced Congenital High Airway Obstruction in a Sheep Model.
abstract: OBJECTIVE
  To evaluate the feasibility of tracheo-amniotic shunting in a sheep model for congenital high airway obstruction syndrome.
  
  
  METHODS
  High airway obstruction was induced around day 95 (term = 145 days) in 10 lamb fetuses by tracheal clipping. Five days later, ultrasound-guided tracheoamniotic shunting was done using either the Harrison double-pigtail bladder stent (HS) or a double-basket device (BS). Caesarean section (CS) was done around day 110. At each time point, the cardiothoracic index (CTI) was measured. Lung-to-body weight ratio (LBWR) was calculated at fetal necropsy. The primary endpoint was successful shunting defined as anatomically correct placement and functional airway decompression; the secondary endpoint was survival until CS.
  
  
  RESULTS
  Two sheep aborted 3 fetuses after tracheal occlusion. Overall, the median CTI at CS was significantly smaller compared to baseline [0.52 (interquartile range, IQR: 0.52-0.54) vs. 0.58 (IQR: 0.54-0.63); p = 0.01]. In the HS group (n = 4), none of the shunts were correctly positioned. In the BS group (n = 3), there was 1 correct shunt placement; however, this fetus was stillborn. Median LBWR suggested pulmonary overgrowth [0.10 (IQR: 0.08-0.11)].
  
  
  CONCLUSIONS
  In our hands, using this model with a long and mobile neck and relative oligohydramnios, tracheoamniotic shunting for airway obstruction has a high failure rate. If further pursued, alternative techniques or different models should be considered.
authors.affiliation: Division of Woman and Child, Clinical Department of Obstetrics and Gynecology, Fetal Medicine Unit, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Philip
authors.initials: P
authors.lastname: DeKoninck
authors.forename: Masayuki
authors.initials: M
authors.lastname: Endo
authors.forename: Jan A
authors.initials: JA
authors.lastname: Deprest
authors.forename: Luc
authors.initials: L
authors.lastname: De Catte
mesh_terms: D000402:Airway Obstruction / Q000601:surgery*; D000818:Animals; D004195:Disease Models, Animal; D005332:Fetoscopy / Q000379:methods*; D012756:Sheep; D014132:Trachea / Q000601:surgery*; D014133:Tracheal Diseases / Q000601:surgery*