Reverse blood flow syndrome is a very serious complication of single conjunctival pregnancies. The etiology is closely related to abnormal vascularization within the placenta. In the first trimester of pregnancy, pathological vascular connections are formed, referred to as anastomosis. Arteriovenous flow occurs and, as a result, blood transfusions between the fetuses are observed. The management of TRAP syndrome involves the separation of the twins' circulatory systems, which is increasingly done as part of intrauterine therapy.

TRAP syndrome( reverse blood flow syndrome ) is one of the rarest complications of unicellular pregnancy and occurs with a frequency of 1: 35,000 pregnancies . Inverted arterial blood flow causes twins to develop abnormally. The twin I referred to as the donor supplies blood not only to himself, but also to the other twin. Therefore, the donor is overloaded with the circulatory system, which translates into the development of congestive circulatory failure, and eventually even hypoxia. Much worse prognosis is determined for the recipient. Improper blood supply causes not only heart atrophy, but also other reduction defects, especially in the upper parts of the body. The most common are: atresia of the gastrointestinal tract, deformation of the limbs or their complete absence, abnormal craniofacial development, as well as a CNS defect, for example holoprosencephaly.

Although the cause of TRAPS is unknown, a karyotype disorder is especially described in a cardiacless twin, and there is an increased incidence of mothers continuing antiepileptic treatment during pregnancy (primidone / oxarbazepine) in their babies.

Symptoms and course of the TRAP syndrome

The clinical manifestation of the syndrome is different in the case of the donor and recipient. A cardless fetus, referred to as the recipient, is characterized by:

  • reduction defects, e.g. acephaly, acrania
  • atrophy of internal organs, including disruption of the digestive tract or lack of lungs and limb defects
  • diaphragmatic hernia
  • swelling of the subcutaneous tissues
  • complete absence or residual heart
  • growth disturbance
  • craniofacial defects, not only cleft lip and / or palate, but even complete absence of a face
  • SUA, i.e. a double umbilical cord (instead of three vessels)

The donor fetus is characterized in turn by:

  • intrauterine growth restriction
  • abdominal and pleural fluid
  • excessive right ventricular hypertrophy, tricuspid regurgitation resulting in severe heart failure
  • enlargement of the parenchymal organs - which is commonly referred to as hepatosplenomegaly
  • stillbirths or death in the neonatal period

In addition to significant disorders in individual twins, single-chorionic pregnancy complicated by TRAP syndrome is associated with an increased risk of complications in the perinatal period. These can be: increased amount of amniotic fluid, premature birth, the consequence of which is prematurity with all the consequences. Moreover, anemia and postpartum hemorrhage are relatively more frequent.

Diagnosis of reverse arterial perfusion syndrome

In order to diagnose the TRAP syndrome, it is necessary to perform an ultrasound examination. There are even criteria developed by a team of experienced specialists. They include, among others lack of movement, failure to visualize the fetal heart rate, hypertrophy of the upper body with the simultaneous normal development of the lower parts. Confirmation of the disease is usually possible only after birth - clinical picture and X-ray examination.

What is the management of a pregnancy complicated by TRAP syndrome

Treatment is only intended to protect the donor twin, as the recipient fetus is doomed to death. The procedure of mechanical separation of the fetal circulatory systems is used. This is done through a cesarean section and the implementation of appropriate postnatal procedures. An alternative is the increasingly common intrauterine procedures - endoscopic vascular ligation completely closes arteriovenous anastomoses between twins. Attempts have been made to treat with pharmacological substances such as indomethacin, which is an inhibitor of prostaglandin synthetase, but the results are not spectacular.

Laser photocoagulation - the most effective therapy

The experience of Polish doctors on this subject is relatively small, but attempts are made to save children with the use of laser closure of abnormal arterial connections between fetuses. The latest reports published an article describing an attempt at coagulation closure of the intra-abdominal vessel lumen.

It should be emphasized that the laser beam should in any case be focused inside the cardless twin. It greatly reduces the risk of damage to the donor's fetus and, moreover, minimizes the riskbleeding.

A major problem during treatments is the identification of the umbilical cord that should be coagulated. Usually both cords are located in close proximity, which makes the entire procedure more difficult. Another problem is usually the much shorter umbilical cord of a cardiac fetus, which should be coagulated. The optimal time for intrauterine procedures is completed 15 t.c.

Category:

Pregnancy