CLINICAL SUMMARY
A 35-day-old female child presented to emergency with episodes of cyanosis and labored breathing. She was born at term gestation, through normal vaginal delivery, and cried at birth with no documented postnatal complications. On examination, the child was in respiratory distress, with tachypnea, chest retractions, and decreased blood oxygen saturation. The child was placed on noninvasive ventilation. Chest radiograph revealed cardiomegaly with pulmonary oligemia. On echocardiography, there was severe pulmonary artery hypertension with dilatation of the right atrium and right ventricle, and severe tricuspid regurgitation. A provisional diagnosis of persistent pulmonary artery hypertension was given. Routine transabdominal ultrasonography showed a large vascular channel draining into the portal vein, which was having hepatopetal flow on color Doppler examination, thus, raising suspicion of infra-cardiac total anomalous pulmonary venous connection (TAPVC).
The child then underwent an electrocardiogram gated computed tomography angiography (CTA) of the heart on a 192-detector scanner. CTA showed situs solitus, levocardia, and left-sided aortic arch. All the four pulmonary veins were seen joining to form a common vertical channel that coursed through the esophageal hiatus to drain into the portal vein, which was dilated. The left branch of the portal vein (LPV) showed fusiform dilatation. A small vascular channel was seen between LPV and Middle Hepatic Vein, which was not running parallel to the latter, suggestive of an intrahepatic portosystemic shunt [Figure 1]. Thus, a radiologic diagnosis of an infra-cardiac type of TAPVC with an intrahepatic portosystemic shunt (Parks type III) was given. There was no evidence of opacification of ductus venous. Intraoperatively, an unobstructed type of infra-cardiac TAPVC was diagnosed, and the child underwent repair for the same. The child, however, passed away on the postoperative day itself.
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Figure 1: Computed tomography angiography images (a-d). Volume rendered image (a) showing the common vertical channel (white arrow) draining into the main portal vein; dilated left branch of the portal vein (yellow arrow) and vascular shunt (white asterisk). Sagittal (b) and axial (c) images showing the vascular shunt (asterisk) between the middle hepatic vein (red arrow) and dilated left branch of the portal vein (yellow arrow). Axial image (d) showing fusiform dilatation of the left branch of the portal vein (yellow arrow). Common vertical channel is also seen in the axial images (white arrows in c and d)
DISCUSSION
TAPVC is an infrequently encountered cardiac anomaly, accounting for about 0.7%–1.5% of the congenital heart disease (CHD) cases.[1] It is characterized by failure of the pulmonary veins to drain into the left atrium, which instead join to form a common channel that drains either into a systemic vein or right atrium depending on the subtype. Conventionally, it has been classified into supra-cardiac, cardiac, infra-cardiac, and mixed types.
Characteristically, in the infra-cardiac subtype, the pulmonary venous confluence (or the common channel) passes vertically through the esophageal hiatus to drain to the venous system below the diaphragm, which is most commonly the portal vein, or a systemic vein like the hepatic veins, inferior vena cava (IVC), or ductus venosus.[2] Most cases of the infra-cardiac subtype are associated with pulmonary venous return obstruction.[2]
The clinical presentation of such patients is variable depending upon the presence and severity of obstruction to pulmonary venous return. TAPVC can be associated with several other congenital cardiac abnormalities, like coarctation of the aorta, atrioventricular septal defect, and double outlet right ventricle, most notable being heterotaxy syndromes. TAPVC has been found in patients with both right as well as left atrial isomerism. Although TAPVC can concomitantly exist with an entire spectrum of cardiac abnormalities, its association with other venous anomalies has been rarely reported.
CTA can provide adequate information about arterial and venous anatomy in children with cyanotic CHD.[3] In the index case, an intrahepatic portosystemic venous shunt was found on CTA, which arises due to an aberration in the development of the embryonic venous system at around 4 weeks of intrauterine life, with one of the proposed causes being a persistent communication between the vitelline and portal venous systems.[4] Park et al.[5] classified IHPSS into four types, with type I being the most common that represents a single large channel between the right branch of the portal vein and the IVC. Type II is a relatively localized shunt in one of the hepatic segments, while type III has an aneurysmal connection between the hepatic and portal vein branches. Type IV shunt shows multiple communications between the portal and hepatic venous branches in the periphery. In the present case, type III shunt was found on CTA. Although most of these shunts regress spontaneously during infancy, management varies depending on the size of the shunt and the clinical manifestations later on in life. Therapeutic options may vary from surgical blading to coil embolization of the shunt. Shunts resulting in encephalopathy due to hyperammonemia or hyperdynamic circulation due to a large fistula require active surgical management. Small intrahepatic portovenous shunts if not symptomatic as seen in our index case do not require surgical management.[6]
To conclude, in a child with TAPVC, a thorough search for co-existing venous anomalies on CT angiography is suggested.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Presented as e-poster at 19th Annual National Conference of Indian Society of Paediatric Radiology (ISPR -2021), virtual conference, held on 30-31st October 2021
Conflicts of interest
There are no conflicts of interest.
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