Premature Closure of the Foramen Ovale and Ductus Arteriosus in a Fetus With Transposition of the Great Arteries
A 32-year-old woman presented for evaluation at 34 weeks gestation complaining of feeling swollen and short of breath for several days. By report, she had received good prenatal care, and a complete ultrasound at 20 weeks gestation revealed no fetal abnormalities and a normal 4-chambered heart. Imaging by the perinatologist prompted immediate referral for a fetal echocardiogram. This study revealed severe cardiomegaly with marked dilation of the left atrium and ventricle (Figure 1). There was normal visceral situs and normal atrioventricular alignment. The pulmonary artery originated from the left ventricle (Figure 2) and the aorta from the right ventricle (Figure 3), making the diagnosis transposition of the great arteries (TGA). The aortic and pulmonary valves were normal in size and architecture. The mitral valve appeared thickened and there was severe regurgitation (Figure 4). The atrial septum was intact and bowed into the right atrium (Figure 5). The ductus arteriosus was identified by 2-dimensional imaging; however, no flow could be documented (Figure 3). The rhythm was sinus at 140 bpm. There was minimal fetal movement and continuous monitoring revealed an abnormal fetal heart rate tracing. Because of the significant concern for fetal well-being, the baby was delivered by Cesarean section emergently in an operating room suite adjacent to the cardiac operating room. On delivery, the baby became immediately cyanotic, limp, and cold. Within seconds, the heart rate dropped to <30 bpm. The baby was intubated, and via a median sternotomy, placed on extracorporeal membrane oxygenation (ECMO) supportusing 2 venous cannulas (1 in each atrial chamber) and 1 aortic cannula. Cannulation was achieved within 6 minutes after delivery, with immediate decompression of the heart and return of a normal heart rate and excellent perfusion. The initial arterial blood gas on ECMO revealed a pH of 7.22 and a Po2 of 485 mm Hg. After 7 days of support, transesophageal echocardiogram revealed significant recovery of the heart. There was mild mitral regurgitation and left ventricular function was good. The findings from the neurological examination and head ultrasound were normal. Viral and metabolic studies to assess for a primary cardiomyopathic process were negative. The baby underwent an arterial switch operation and was successfully weaned from bypass. After 45 minutes, pulmonary hypertension developed and the baby was placed back on ECMO. Within 24 hours, pulmonary artery pressure returned to normal. Unfortunately, during this time, the baby sustained a significant intraventricular hemorrhage in the brain and support was electively withdrawn at the family’s request.
We believe that this case represents the hemodynamic result of premature foramen ovale and ductus arteriosus closure in a fetus with TGA. Undetected, this combination would have resulted in fetal demise. The immediate delivery of the baby and initiation of ECMO restored a circulation that was compatible with life. This case demonstrates that, in addition to the structural anatomy, a complete assessment of cardiac physiology throughout gestation is very important in the management of fetuses with congenital heart disease.
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke's Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
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