Acute Maternal Hyperoxygenation for Fetal Transposition of the Great Arteries (TGA)

Study Overview
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Brief Summary
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This prospective study will examine whether transient maternal hyperoxygenation is useful as a diagnostic test to more accurately detect TGA patients with poor vs. good neonatal intra-cardiac mixing of blood, based on the in-utero response to oxygen exposure.

Detailed Description
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This is a prospective pilot study to examine whether transient maternal hyperoxygenation is useful as a diagnostic test to more accurately detect TGA patients with poor vs. good neonatal intracardiac mixing of blood, based on the in-utero response to oxygen exposure. Acute maternal oxygen administration will transiently increase the fetal oxygen levels to those reached at birth with spontaneous breathing, thus simulating conditions that will naturally occur at the time of birth. Echocardiogram and MRI will be used to examine the effects on the fetal circulation. The prenatal findings will then be compared to the neonatal presentation. The investigators postulate that conditions that predispose newborns to acute neonatal compromise will be detectable and distinguishable prior to birth by echocardiography, MRI, or by combining the findings of both exams.

Official Title
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Transposition of the Great Arteries: Prenatal Anatomical and Hemodynamic Findings Associated With Perinatal Outcomes

Conditions
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TGA - Transposition of Great Arteries

Intervention / Treatment
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* Drug: Oxygen gas


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Fetus with simple TGA +/- small VSD Intention of active postnatal management after birth Exclusion Criteria: Fetus with complex form of TGA Significant fetal arrhythmia Major non-cardiac lesions Maternal contraindications for fetal MRI

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Oxygen gas<br>10-15 L/min of oxygen by face mask for up to 45 minutes for the MRI and up to 30 minutes for the echocardiogram. | Drug: Oxygen gas<br>* Brief maternal administration of 65-70% O2 via a face mask during the last trimester<br>* Other names: Praxair;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fetal intracardiac/ductal shunting measured by echocardiogram flow patterns and MRI fluximetry | Characterize effects of maternal hyperoxygenation on fetal intracardiac shunting measured using MRI fluximetry (ml/min/m2) of AAo, DA, SVC, IVC, UV, and DA. Ductal shunting measured using echo measurements of atrial septal morphology (2D; 4D) and foramen flow (color; 4D flow) of FO diameter and septal excursion. Ductus arteriosus flow (color and Doppler): minimal diameter, reversed end-diastolic flow, systolic peak flow, forward-reverse flow ratio, flow restriction. | Outcome measure obtained during hyperoxygenation while undergoing echocardiography and MRI | 
| Fetal pulmonary blood flow measured by MRI fluximetry | Characterize effects of maternal hyperoxygenation on fetal pulmonary blood flow using MRI fluximetry (ml/min/m2) measures of Main PA, RPA and LPA | Outcome measure obtained during hyperoxygenation while undergoing echocardiography and MRI | 
| Neonatal outcomes | As measure of patient morbidity, a composite score of 10 variables will be used, assigning a value of 1 for each event that occurred 1) respiratory distress syndrome requiring surfactant; 2) cardiopulmonary resuscitation requiring chest compressions; 3) cerebral vascular injury (intra-ventricular or -parenchymal hemorrhage, ischemic stroke); 4) necrotizing enterocolitis; 5) need of ECMO; 6) infections associated with health care (bloodstream, surgical site, and urinary tract infection); 7) unplanned re-intubation; 8) re-operation for residual cardiac lesions; 9) interventional catheterization for residual cardiac lesions; and 10) unplanned intensive care readmission. | Intrauterine demise to hospital discharge, or up to 1 year of age if pulmonary hypertension exists | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fetal cerebral perfusion | Effects of maternal hyperoxygenation on fetal cerebral perfusion measured by change in cDO2 (mL/min/m2) and cVO2 (mL/min/m2) | Outcome measure obtained during maternal hyperoxygenation while undergoing echocardiography and MRI | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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maternal hyperoxygenation, fetal echocardiography, fetal MRI