Donald School Journal of Ultrasound in Obstetrics and Gynecology

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VOLUME 17 , ISSUE 4 ( October-December, 2023 ) > List of Articles


TRAP Sequence, Diagnosis, Treatment, and Outcome

Gordana Adamova, Elma A Hasanagovski

Keywords : Acardiacus, Case report, Twin reversed arterial perfusion sequence, Ultrasound

Citation Information : Adamova G, Hasanagovski EA. TRAP Sequence, Diagnosis, Treatment, and Outcome. Donald School J Ultrasound Obstet Gynecol 2023; 17 (4):360-363.

DOI: 10.5005/jp-journals-10009-1991

License: CC BY-NC 4.0

Published Online: 28-12-2023

Copyright Statement:  Copyright © 2023; The Author(s).


Twin reversed arterial perfusion (TRAP), a rare condition (0.3:10,000) that occurs in monochorionic twin pregnancies, with the coexistence of a normal “pump twin” and an acardiac twin. The acardiac twin is parasitic, using an anomalous reversal of umbilical arterial flow. This anastomosis occurs in the 3rd–4th week of gestation, and the acardiac twin puts the pump fetus at risk of high-output cardiac failure. The pump twin has a mortality rate of up to 55%. Antenatal ultrasound recognition in the first trimester Doppler confirmation of the diagnosis of TRAP sequence in twin pregnancies aids in proper prenatal diagnosis. Presented is a 26-year-old woman, gravida para, who came to our hospital at 19th gestational week (GW). The first ultrasound showed a twin monochorionic/diamniotic pregnancy, with one normally developed fetus and an atypical mass without a heart. The patient was previously monitored elsewhere, but TRAP syndrome wasn't identified. We followed her until the 26th week, and she was later sent to a tertiary center for further conservative treatment in the absence of operative treatment in our country. The patient gave birth via C-section in the 32nd gestation week. The normal twin was born in good condition and was sent home after a few weeks.

  1. Hecher K, Ville Y, Nicolaides KH. Color Doppler ultrasonography in the identification of communicating vessels in twin-twin transfusion syndrome and acardiac twins. J Ultrasound Med 1995;14(1):37–40. DOI: 10.7863/jum.1995.14.1.37
  2. Chandramouly M, Namitha. Case series: TRAP sequence. Indian J Radiol Imaging 2009;19(1):81–83. DOI: 10.4103/0971-3026.45352
  3. Bornstein E, Monteagudo A, Dong R, et al. Detection of twin reversed arterial perfusion sequence at the time of first-trimester screening: the added value of 3-dimensional volume and color Doppler sonography. J Ultrasound Med 2008;27(7):1105–1109. DOI: 10.7863/jum.2008.27.7.1105
  4. Pagani G, D'Antonio F, Khalil A, et al. Intrafetal laser treatment for twin reversed arterial perfusion sequence: cohort study and meta-analysis. Ultrasound Obstet Gynecol 2013;42(1):6–14. DOI: 10.1002/uog.12495
  5. Wong AE, Sepulveda W. Acardiac anomaly: current issues in prenatal assessment and treatment. Prenat Diagn 2005;25(9):796–806. DOI: 10.1002/pd.1269
  6. Sepúlveda WH, Quiroz VH, Giuliano A, et al. Prenatal ultrasonographic diagnosis of acardiac twin. J Perinat Med 1993;21(3):241–246. DOI: 10.1515/jpme.1993.21.3.241
  7. Egan JF, Borgida AF. Ultrasound evaluation of multiple pregnancies. In: Callen PW (Ed). Ultrasonography in Obstetrics and Gynecology, 5th edition. Pennsylvania: WB Saunders; 2008. pp. 286–288.
  8. Malone FD, D'Alton ME. Anomalies peculiar to multiple gestations. Clin Perinatol 2000;27(4):1033–46. DOI: 10.1016/s0095-5108(05)70062-2
  9. Barré M, Le Vaillant C, Boog G, et al. [Acardiac twins: pronostics markers’ study]. Gynecol Obstet Fertil 2012;40(2):93–98. DOI: 10.1016/j.gyobfe.2011.08.011
  10. Hirose M, Murata A, Kita N, et al. Successful intrauterine treatment with radiofrequency ablation in a case of acardiac twin pregnancy complicated with a hydropic pump twin. Ultrasound Obstet Gynecol 2004;23(5):509–512. DOI: 10.1002/uog.1011
  11. Vitucci A, Fratelli N, Fichera A, et al. Timing of intra-fetal laser therapy for twin reversed arterial perfusion (TRAP) sequence: Retrospective series and systematic review and meta-analysis. Int J Gynaecol Obstet 2022;159(3):833–840. DOI: 10.1002/ijgo.14221
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