title: Time-interval analysis of ductus venosus flow velocity waveforms in twin-to-twin transfusion syndrome treated with laser surgery.
abstract: OBJECTIVE
  To investigate time-interval variables of ductus venosus (DV) flow velocity waveforms (FVWs) in twin-to-twin transfusion syndrome (TTTS), comparing the results with reference ranges from normal singleton fetuses. The impact of laser surgery and the effect of prognostic factors were also evaluated.
  
  
  METHODS
  In 107 TTTS cases, DV-FVWs of both recipients and donors were recorded 1 day before and 2 days after laser therapy. Time intervals for systolic (S) and early diastolic (D) peaks were analyzed retrospectively with regard to acceleration time (acc-S and acc-D for S and D, respectively) and deceleration time (dec-S and dec-D for S and D, respectively). For each variable, Z-scores were calculated with respect to previously reported normal reference ranges.
  
  
  RESULTS
  Z-scores for all variables showed statistically significant differences from those observed previously in normal fetuses, with the exception of dec-S of donors. The most striking differences were observed in longer dec-S of recipients (P < 0.001) and longer dec-D of donors (P < 0.001). Laser therapy showed significant impact on dec-S and acc-D in recipients and on all variables in donors. Regarding the short-term prognosis, acc-S and dec-S showed significant differences for the prediction of intrauterine fetal demise in donors (P = 0.009 and P = 0.011, respectively).
  
  
  CONCLUSIONS
  This study demonstrates that time-interval variables of DV-FVWs may differentiate the characteristic hemodynamic changes caused by unbalanced blood volume between recipients and donors.
authors: Department of Obstetrics and Gynecology, Osaka City University Graduate School of Medicine, Osaka, Japan; Department of Obstetrics and Fetal Medicine, University Medical Center, Hamburg-Eppendorf, Hamburg, Germany.
authors: D
authors: D
authors: Tachibana
authors: P
authors: P
authors: Glosemeyer
authors: W
authors: W
authors: Diehl
authors: K
authors: K
authors: Nakagawa
authors: N
authors: N
authors: Wada
authors: Y
authors: Y
authors: Kurihara
authors: M
authors: M
authors: Fukui
authors: M
authors: M
authors: Koyama
authors: K
authors: K
authors: Hecher
mesh_terms: D001783:Blood Flow Velocity; D005260:Female; D005330:Fetofetal Transfusion / Q000000981:diagnostic imaging* / Q000196:embryology / Q000503:physiopathology / Q000601:surgery; D005332:Fetoscopy / Q000379:methods*; D005333:Fetus / Q000098:blood supply*; D005865:Gestational Age; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D011247:Pregnancy; D011379:Prognosis; D012016:Reference Values; D012189:Retrospective Studies; D016216:Ultrasonography, Prenatal; D014471:Umbilical Veins / Q000000981:diagnostic imaging* / Q000196:embryology
keywords: ductus venosus; laser surgery; monochorionic twins; time-related analysis; twin-to-twin transfusion syndrome