Book contents
- Frontmatter
- Contents
- Contributors
- Foreword
- Preface
- Section 1 General principles
- Section 2 Fetal disease
- Chapter 6 Red cell alloimmunization
- Chapter 7 Fetal and neonatal alloimmune thrombocytopenia
- Chapter 8.1 Fetal dysrhythmias
- Chapter 8.2 Fetal dysrhythmias
- Chapter 9.1 Structural heart disease
- Chapter 9.2 Structural heart disease
- Chapter 9.3 Structural heart disease
- Chapter 10.1 Manipulation of amniotic fluid volume
- Chapter 10.2 Manipulation of amniotic fluid volume
- Chapter 11.1 Twin-to-twin transfusion syndrome
- Chapter 11.2 Twin-to-twin transfusion syndrome
- Chapter 11.3 Twin-to-twin transfusion syndrome
- Chapter 11.4 Twin-to-twin transfusion syndrome
- Chapter 11.5 Twin-to-twin transfusion syndrome
- Chapter 12.1 Twin reversed arterial perfusion (TRAP) sequence
- Chapter 12.2 Twin reversed arterial perfusion (TRAP) sequence
- Chapter 13.1 Fetal infections
- Chapter 13.2 Fetal infections
- Chapter 14.1 Fetal urinary tract obstruction
- Chapter 14.2 Fetal urinary tract obstruction
- Chapter 14.3 Fetal urinary tract obstruction
- Chapter 14.4 Fetal urinary tract obstruction
- 15.1 Fetal lung growth, development, and lung fluid
- Chapter 15.2 Fetal lung growth, development, and lung fluid
- Chapter 16.1 Neural tube defects
- Chapter 16.2 Neural tube defects
- Chapter 17.1 Fetal tumors
- Chapter 17.2 Fetal tumors
- Chapter 18.1 Intrauterine growth restriction
- Chapter 18.2 Intrauterine growth restriction
- Chapter 19.1 Congenital diaphragmatic hernia
- Chapter 19.2 Congenital diaphragmatic hernia
- Chapter 20.1 Fetal stem cell transplantation
- Chapter 20.2 Fetal stem cell transplantation
- Chapter 20.3 Fetal stem cell transplantation
- Chapter 21 Gene therapy
- Chapter 22 The future
- Glossary
- Index
- References
Chapter 12.2 - Twin reversed arterial perfusion (TRAP) sequence
In-Utero treatment
from Section 2 - Fetal disease
Published online by Cambridge University Press: 05 February 2013
- Frontmatter
- Contents
- Contributors
- Foreword
- Preface
- Section 1 General principles
- Section 2 Fetal disease
- Chapter 6 Red cell alloimmunization
- Chapter 7 Fetal and neonatal alloimmune thrombocytopenia
- Chapter 8.1 Fetal dysrhythmias
- Chapter 8.2 Fetal dysrhythmias
- Chapter 9.1 Structural heart disease
- Chapter 9.2 Structural heart disease
- Chapter 9.3 Structural heart disease
- Chapter 10.1 Manipulation of amniotic fluid volume
- Chapter 10.2 Manipulation of amniotic fluid volume
- Chapter 11.1 Twin-to-twin transfusion syndrome
- Chapter 11.2 Twin-to-twin transfusion syndrome
- Chapter 11.3 Twin-to-twin transfusion syndrome
- Chapter 11.4 Twin-to-twin transfusion syndrome
- Chapter 11.5 Twin-to-twin transfusion syndrome
- Chapter 12.1 Twin reversed arterial perfusion (TRAP) sequence
- Chapter 12.2 Twin reversed arterial perfusion (TRAP) sequence
- Chapter 13.1 Fetal infections
- Chapter 13.2 Fetal infections
- Chapter 14.1 Fetal urinary tract obstruction
- Chapter 14.2 Fetal urinary tract obstruction
- Chapter 14.3 Fetal urinary tract obstruction
- Chapter 14.4 Fetal urinary tract obstruction
- 15.1 Fetal lung growth, development, and lung fluid
- Chapter 15.2 Fetal lung growth, development, and lung fluid
- Chapter 16.1 Neural tube defects
- Chapter 16.2 Neural tube defects
- Chapter 17.1 Fetal tumors
- Chapter 17.2 Fetal tumors
- Chapter 18.1 Intrauterine growth restriction
- Chapter 18.2 Intrauterine growth restriction
- Chapter 19.1 Congenital diaphragmatic hernia
- Chapter 19.2 Congenital diaphragmatic hernia
- Chapter 20.1 Fetal stem cell transplantation
- Chapter 20.2 Fetal stem cell transplantation
- Chapter 20.3 Fetal stem cell transplantation
- Chapter 21 Gene therapy
- Chapter 22 The future
- Glossary
- Index
- References
Summary
Background
Twin reversed arterial perfusion (TRAP) sequence or acardiac twinning is a rare congenital anomaly unique to monozygotic multiple gestations. Existence of TRAP requires two conditions: (1) pump or forward flow failure in the acardiac twin and (2) a set of arterioarterial and venovenous placental anastomoses connecting the acardiac and “pump” twins’ circulatory systems. It is considered the most severe malformation of twinning seen in humans. Other historical though less commonly used terms include chorioangiopagus parasiticus and acardiac monster. Incidence is estimated to be 1:35000 pregnancies or 1% of all monochorionic pregnancies [1, 2], though it may be higher given that some cases of TRAP may go undiagnosed due to early pregnancy loss or reabsorption of the acardiac twin [3].
Pathophysiology
In TRAP, one twin, the acardiac, has a non-functioning (pseudoacardius) or absent (holoacardius) heart. This twin is hemodynamically dependent on the structurally normal donor or “pump” twin. Blood is shunted from the “pump” twin, bypassing the placenta, in a retrograde fashion through anomalous arterioarterial anastomoses and perfuses the acardiac twin [4]. The blood reaching the acardiac twin is poorly oxygenated and nutrient deplete. Once in the acardiac’s circulatory system, blood flows passively through the iliac arteries, first perfusing the lower body and extremities. The further deoxygenated blood then perfuses the caudal structures and subsequently flows via the acardiac’s umbilical vein back to the “pump” twin through direct venovenous anastomoses (see Figure 12.2.1). Thus, blood returning to the “pump” twin is a mix of oxygenated blood from the placenta and deoxygenated blood from the acardiac twin.
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- Fetal TherapyScientific Basis and Critical Appraisal of Clinical Benefits, pp. 193 - 199Publisher: Cambridge University PressPrint publication year: 2012