title: Vascular pattern in monochorionic placentas with spontaneous TAPS and TTTS with residual anastomoses after laser: a case-control study.
abstract: OBJECTIVE
  This study aimed to compare the angio-architecture of monochorionic placentas of spontaneous twin anaemia-polycythemia sequence (TAPS) with placenta of twin-to-twin transfusion syndrome (TTTS) with residual anastomoses after laser coagulation and placentas of uncomplicated monochorionic twin pregnancies.
  
  
  METHODS
  This case-control study compares the angio-architecture of monochorionic placentas of spontaneous TAPS (n = 12) with that of monochorionic placentas of TTTS treated by laser coagulation with residual anastomoses (TTTS + RA; n = 20) and placentas of monochorionic pregnancies without complications (n = 24), matched for gestational age. Placental sharing and angio-architecture were assessed by injection of colored dye.
  
  
  RESULTS
  The median diameter of the arterio-venous (AV) anastomoses in TAPS placentas was 2.26, 0.215 with TTTS + RA and 4.17 mm in normal monochorionic pregnancies (p < .03). The mean diameter of the arterio-arterial (AA) anastomoses in monochorionic placentas with spontaneous TAPS was 0.2 mm versus 0.15 mm in TTTS + RA and 2.0 mm in normal pregnancies, respectively (p < 0.03, p < 0.007). The number of AA anastomoses was lower with TAPS (0.3 versus 0.50 and 1, respectively, p < 0.015, p < 0.0001). Besides, unequal sharing was more frequent in TAPS as compared with monochorionic normal pregnancies (75% versus 29%, p = 0.03).
  
  
  CONCLUSIONS
  Age matched placentas of spontaneous TAPS are characterized by very small AV anastomoses and very few AA anastomoses of smaller diameter than placentas of monochorionic twins with TTTS or without obvious complications.
authors.affiliation: Fetal Medicine, CMCO-HUS, 19 Rue Louis Pasteur, 67300, Schiltigheim/Strasbourg, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Favre
authors.forename: Antoine
authors.initials: A
authors.lastname: Koch
authors.forename: Aenn-Sophie
authors.initials: AS
authors.lastname: Weingertner
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sananes
authors.forename: Ngoc Tu
authors.initials: NT
authors.lastname: Trieu
authors.forename: Monique
authors.initials: M
authors.lastname: Kohler
authors.forename: Fernando
authors.initials: F
authors.lastname: Guerra
authors.forename: Israel
authors.initials: I
authors.lastname: Nisand
mesh_terms: D000328:Adult; D000740:Anemia / Q000150:complications / Q000151:congenital / Q000473:pathology / Q000601:surgery; D001163:Arteriovenous Anastomosis / Q000473:pathology* / Q000601:surgery; D016022:Case-Control Studies; D004200:Diseases in Twins / Q000473:pathology* / Q000601:surgery; D005260:Female; D005330:Fetofetal Transfusion / Q000150:complications / Q000473:pathology* / Q000601:surgery; D006801:Humans; D017075:Laser Coagulation; D010920:Placenta / Q000098:blood supply* / Q000473:pathology / Q000601:surgery; D010922:Placenta Diseases / Q000209:etiology / Q000473:pathology / Q000601:surgery; D011086:Polycythemia / Q000150:complications / Q000151:congenital / Q000473:pathology* / Q000601:surgery; D011247:Pregnancy; D059285:Pregnancy, Twin; D014430:Twins, Monozygotic; D055815:Young Adult