title: Veno-venous anastomoses in twin-twin transfusion syndrome: A multicenter study.
abstract: BACKGROUND
  The aim of this study is to evaluate the prevalence of veno-venous (VV) anastomoses in a large cohort of monochorionic (MC) twin placentas with twin-twin transfusion syndrome (TTTS) compared to a control group of MC placentas without TTTS.
  
  
  METHODS
  All TTTS placentas not treated with fetoscopic laser surgery (TTTS group) and examined at five international fetal therapy centers were included in this study and compared with a control group of MC placentas without TTTS (non-TTTS group). MC placentas were routinely injected with colored dye. We recorded the presence of VV and arterio-arterial (AA) anastomoses.
  
  
  RESULTS
  A total of 414 MC placentas were included in this study (TTTS group, n = 106; non-TTTS group, n = 308). The prevalence of VV anastomoses was significantly higher in the TTTS group than in the non-TTTS group, 36% (38/106) and 25% (78/308), respectively (p = .04; odds ratio (OR) 1.65; 95% confidence interval (CI): 1.03-2.64). In the subgroup of MC placentas without AA anastomoses, the prevalence of VV anastomoses in the TTTS group and non-TTTS group was 32% (18/57) and 8% (2/25), respectively (p = .03; OR: 5.31; 95% CI: 1.13-24.98).
  
  
  CONCLUSIONS
  VV anastomoses are detected more frequently in TTTS placentas than in MC placentas without TTTS and may thus play a role in the development of TTTS.
authors.affiliation: Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: d.zhao@lumc.nl.
authors.forename: D P
authors.initials: DP
authors.lastname: Zhao
authors.affiliation: Hospital Italiano de Buenos Aires, Argentina.
authors.forename: O
authors.initials: O
authors.lastname: Cambiaso
authors.affiliation: Hospital Italiano de Buenos Aires, Argentina.
authors.forename: L
authors.initials: L
authors.lastname: Otaño
authors.affiliation: Fetal and Maternal Medicine, University Hospitals Leuven, Leuven, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: Lewi
authors.affiliation: Fetal and Maternal Medicine, University Hospitals Leuven, Leuven, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Deprest
authors.affiliation: Fetal Medicine Unit, Department of Obstetrics, Shanghai First Maternity and Infant Hospital, Shanghai, China.
authors.forename: L M
authors.initials: LM
authors.lastname: Sun
authors.affiliation: Fetal Medicine Unit, Department of Obstetrics, Shanghai First Maternity and Infant Hospital, Shanghai, China.
authors.forename: T
authors.initials: T
authors.lastname: Duan
authors.affiliation: Division of Fetal Medicine, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: D
authors.initials: D
authors.lastname: Oepkes
authors.affiliation: Department of Pathology, Women and Infants Hospital, Providence, RI, USA.
authors.forename: S
authors.initials: S
authors.lastname: Shapiro
authors.affiliation: Department of Pathology, Women and Infants Hospital, Providence, RI, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: De Paepe
authors.affiliation: Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Lopriore
mesh_terms: D005260:Female; D005330:Fetofetal Transfusion / Q000453:epidemiology* / Q000601:surgery; D005332:Fetoscopy; D006801:Humans; D008297:Male; D011247:Pregnancy; D015995:Prevalence; D014430:Twins, Monozygotic; D016157:Vascular Fistula / Q000453:epidemiology* / Q000601:surgery
keywords: Monochorionic placenta; Twin–twin transfusion syndrome; Veno–venous anastomoses