Teaching Case

A 2-day-old full term African American male patient was referred for further evaluation of a prominent grade IV systolic murmur observed immediately following delivery. The infant arrived in respiratory distress on high flow oxygen. Respiratory support was escalated from CPAP to intubation with prostaglandin administration for congenital cardiac abnormality concerns.

Pre-operative MRA was performed using steady-state free precession localisers in axial, coronal, and sagittal projections under general anaesthesia. Images demonstrated a Type III infradiaphragmatic TAPVR with all four pulmonary veins draining into the vertical collecting vein draining into the hepatic vein through ductus venosus. Kinking of the ductus venosus, causing turbulent flow with pre-stenotic dilation of the vertical vein was also observed. Severe tricuspid regurgitation was present as well as an enlarged central pulmonary artery due to right to left shunt with volume overload.

Background: Infradiaphragmatic total anomalous pulmonary venous return (TAPVR) is one of multiple types of congenital heart defects that results in sub-optimal oxygen rich blood return to the left atrium. From an embryological perspective, TAPVR results from the failure of the left atrium to link with the primitive pulmonary venous plexus, maintaining the early umbilicovitelline and cardinal venous systems. This lack of connection can result in multiple variants which are classified based on site of the abnormal pulmonary venous drainage. In our patient, all four pulmonary veins formed an abnormal connection below the heart as a consequence of continued pulmonary vein linkage to the umbilicovitelline venous system. These veins joined to form a common vertical collecting vein draining into the hepatic vein via the ductus venous [1].

Clinical Perspective: Acute management of congenital cardiac defects is vital for newborn survival. TAPVR is one of the cyanotic newborn syndromes in which the patient will present with characteristic cyanosis. Additionally, patients will likely present in respiratory distress which should suggest underlying cardiopulmonary pathology. Prostaglandins should be delivered immediately in situations suggestive of congenital defects.

Imaging Perspective: A complete trans-thoracic echocardiogram and cardiac MRI with gadolinium were obtained, which showed structural malformations consistent with infradiaphragmatic TAPVR with all four pulmonary veins leading into a vertical vein collector draining into the hepatic vein via the ductus venosus. Findings are demonstrated in Figures 1-4.

Outcome: Surgical intervention was recommended and pursued within 2 days of identification. Repair was uncomplicated and the patient remains under routine surveillance to monitor appearance of anastomotic gradient which could complicate the prognosis.

Teaching Points: Infradiaphragmatic TAPVR is the second least common variant resulting in sub-optimal oxygen-rich blood return to the left atrium [2]. It is necessary to maintain a patent ductus arteriosus via prostaglandin administration in these patients to ensure adequate venous return prior to further evaluation. Intraoperative findings confirmed the above detailed imaging findings. Surgical repair of the defect was uncomplicated and recent literature reports a 5-year post-operative survival rate of 92.6% without a gradient across the anastomosis [3].