title: Intertwin anastomoses in monochorionic placentas after fetoscopic laser coagulation for twin-to-twin transfusion syndrome: is there more than meets the eye?
abstract: OBJECTIVE
  This study was undertaken to detect missed anastomoses on the chorionic surface as well as hidden connections in the depth of the cotyledons in placentas after laser coagulation for twin-to-twin transfusion syndrome (TTTS) and to correlate these findings to clinical outcome.
  
  
  METHODS
  All cord vessels were injected with dyed barium sulphate. A digital photograph of the chorionic surface angioarchitecture and single-shot digital X-ray (Rx) angiograms were made. The presence and diameter of any missed anastomoses on the chorionic surface and of any hidden angiographic connections were determined.
  
  
  RESULTS
  Fifty placentas were analyzed, 7 of double intrauterine fetal death (IUFD) and 43 of double survivors. In 9 of 43 (21%) cases with double survival and in all 7 cases of double IUFD, missed anastomoses were identified that should have been ablated by laser coagulation (P < .001). There appeared to be a correlation between the type and diameter of missed anastomoses on the chorionic surface and the clinical outcome. Placentas with missed large arteriovenous/venoarterial anastomoses (AV/VA) (N = 8) were from cases with recurrent TTTS or double IUFD (unless compensated by a large arterioarterial anastomosis [AA]). Next, missed small AV/VA (N = 4) without AA resulted in isolated (ie, without TTTS) discordant hemoglobin levels requiring intrauterine transfusion. Finally, when there were no missed anastomoses (N = 34), TTTS had resolved in all cases and outcome was good, although 1 case had discordant hemoglobin values treated with a single intrauterine transfusion and 4 others had discordant hemoglobin at birth. On Rx angiography, potential hidden connections were present, all but 1 case.
  
  
  CONCLUSIONS
  Coagulation of all anastomoses visible on the chorionic surface seems adequate to treat TTTS. However, hidden connections in the depth of the cotyledon could not be excluded and may be involved in lesser degrees of intertwin transfusion.
authors.affiliation: UZ-Gasthuisberg, Leuven, Belgium.
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Lewi
authors.forename: Jacques
authors.initials: J
authors.lastname: Jani
authors.forename: Mieke
authors.initials: M
authors.lastname: Cannie
authors.forename: Romaine
authors.initials: R
authors.lastname: Robyr
authors.forename: Yves
authors.initials: Y
authors.lastname: Ville
authors.forename: Kurt
authors.initials: K
authors.lastname: Hecher
authors.forename: Eduardo
authors.initials: E
authors.lastname: Gratacos
authors.forename: Hilde
authors.initials: H
authors.lastname: Vandecruys
authors.forename: Vincent
authors.initials: V
authors.lastname: Vandecaveye
authors.forename: Steven
authors.initials: S
authors.lastname: Dymarkowski
authors.forename: Jan
authors.initials: J
authors.lastname: Deprest
mesh_terms: D002823:Chorion / Q000098:blood supply* / Q000473:pathology / Q000601:surgery*; D005260:Female; D005330:Fetofetal Transfusion / Q000601:surgery*; D005332:Fetoscopy; D006801:Humans; D017075:Laser Coagulation / Q000379:methods; D010920:Placenta / Q000098:blood supply* / Q000473:pathology / Q000601:surgery*; D011247:Pregnancy; D017741:Survivors; D016157:Vascular Fistula / Q000601:surgery*