title: Survival after laser surgery for twin-to-twin transfusion syndrome: when are they out of the woods?
abstract: OBJECTIVE
  Severe, progressive twin-to-twin transfusion syndrome (TTTS) is associated with near-100% mortality if left untreated. Endoscopic laser ablation of placental vessels (ELA) is associated with 75% to 80% survival of at least one twin. The actuarial risk of fetal demise after ELA has not yet been described.
  
  
  METHODS
  A retrospective cohort study from 2 centers on a consecutive series of 163 sets of monochorionic twins with severe TTTS (18 Quintero stage I, 55 stage II, 71 stage III, 19 stage IV) who underwent ELA. Actuarial survival was calculated and stratified for donor vs recipient and according to stage.
  
  
  RESULTS
  Median gestational age at diagnosis was 20.1 weeks; median operative time was 60 minutes. Overall survival was 63%, and survival of at least one twin was seen in 76% of pregnancies. Of fetal demises, 10% occurred within 48 hours after ELA, and 90% of all fetal demises occurred within 1 month. There was a 10% survival advantage of recipients over donors. Survival was similar for stages I, II, and IV (75%-80%), compared with 55% for stage III.
  
  
  CONCLUSIONS
  Actuarial survival curves for TTTS confirms a greater burden on donor than on recipient but not at a previously reported 2:1 ratio. The current staging system does not accurately reflect post-ELA mortality risk. The unexpected higher mortality in stage III may reflect a more acute progression of the disorder in this group, an adverse effect of LA on an as yet unknown subgroup with stage III or, alternatively, preoperative demise of fulminant stage IV patients, leaving a stage IV subgroup with a more benign course and better outcome.
authors.affiliation: Fetal Treatment Program, The Warren Alpert Medical School of Brown University, Providence, RI 02903, USA. christopher_muratore@brown.edu
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Muratore
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Carr
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Lewi
authors.forename: Roland
authors.initials: R
authors.lastname: Delieger
authors.forename: Marshall
authors.initials: M
authors.lastname: Carpenter
authors.forename: Jacques
authors.initials: J
authors.lastname: Jani
authors.forename: Jan A
authors.initials: JA
authors.lastname: Deprest
authors.forename: Francois I
authors.initials: FI
authors.lastname: Luks
mesh_terms: D004724:Endoscopy; D005260:Female; D005330:Fetofetal Transfusion / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D011247:Pregnancy; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D015996:Survival Rate; D018084:Ultrasonography, Interventional; D016216:Ultrasonography, Prenatal