Hemodynamic consequences of a restrictive ductus arteriosus and foramen ovale in fetal transposition of the great arteries.

Abstract

D-transposition of the great arteries (D-TGA) is the most commonly diagnosed cyanotic congenital heart disease presenting in the neonatal period. The survival after an arterial switch operation, with freedom from adverse cardiovascular events, has been reported to be as high as 93% at 25 years. However, despite excellent surgical outcomes, there continues to be significant preoperative morbidity and potential mortality due to compromise in the delivery room from foramen ovale closure requiring urgent balloon atrial septostomy for stabilization in the first minutes of life. The prenatal diagnosis of D-TGA using fetal echocardiography has aided in the perinatal management and delivery planning of these infants, lowering preoperative morbidity and mortality and preventing delivery room compromise. Fetuses with D-TGA have more highly oxygenated blood supplying the pulmonary arteries and ductus arteriosus which likely results in ductal constriction and increased pulmonary blood flow. This may be the cause of foramen ovale restriction or closure in-utero, which then increases the risk for postnatal compromise at delivery. Theories regarding the cause of the abnormal pulmonary vasculature that may be seen in D-TGA, including aorto-pulmonary collateral formation, have been proposed but to our knowledge, observation of the ultrasound findings throughout mid and late gestation describing the progression of the abnormal fetal physiology have not been previously described. We present a case of D-TGA in which serial assessment using fetal echocardiography enabled observation of the in-utero progression of disease, predicting postnatal compromise and facilitating the planning of life-saving specialized delivery room care and intervention.