Discussion

Total anomalous pulmonary venous return is rare accounting for about <2% of all congenital cardiac anomalies. There are four types described by the Darling classification. The infracardiac (type III) represents 26% of cases with connections to the hepatic veins, inferior vena cava, portal vein, or ductus venosus. ^{Reference Coley7} A significant proportion of the infradiaphragmatic type are associated with other congenital anomalies including cardiac lesions and heterotaxy syndromes. ^{Reference Duff, Nihill and McNamara1,Reference Louis, Harvey and Menk2} There is evidence of an inheritable genetic link. Those with obstructed veins at presentation, 87% of infracardiac type, and other anomalies have poorer outcomes. ^{Reference Louis, Harvey and Menk2,Reference Coley7}

The association with gastric varices is rare with only a handful of cases in the literature. The cause of development of gastric varices is unknown, most likely related to the degree of obstruction of the path of alternative pulmonary venous drainage. Chen et al describe two neonatal cases of oesophageal varices with no anastomosis between the anomalous pulmonary vein and portal venous system, which precludes portal hypertension as a prerequisite for the formation of varices. ^{Reference Chen, Chen and Li8,Reference Park, Lee, Ban, Jo and Sung9} Laurence and Brown described infradiaphragmatic common vein draining directly only to the left gastric vein. ^{Reference Laurence and Brown6} Oesophageal varices have been described causing upper gastrointestinal haemorrhage in uncorrected infradiaphragmatic total anomalous pulmonary venous return. ^{Reference Laurence and Brown6}

Our patient had two subdiaphragmatic connections: one to the ductus venosus and one to the gastric veins. Given the rapid clinical deterioration, the alternate drainage via the gastric/gastroepiploic venous system was inefficient in decompressing the pulmonary venous hypertension caused by the closing ductus venosus.

Early in embryonic development, the pulmonary and splanchnic venous plexuses are connected via the common cardinal and the umbilico-vitelline venous systems. ^{Reference Kao, Hsieh, Cheng, Chiang and Huang10} In the fourth week of gestation, the lung buds are enmeshed by the pulmonary venous plexus and the splanchnic venous plexus. ^{Reference Kao, Hsieh, Cheng, Chiang and Huang10} In the second month, a common pulmonary vein invagination develops from the posterior wall of the left atrium and subsequently connects with the pulmonary venous plexus as the splanchnic connections involute. Failure of this connection to form can lead to persistence of the splanchnic connections. ^{Reference Kao, Hsieh, Cheng, Chiang and Huang10} This would explain the “common vertical vein” having connections to both the ductus venosus and/or left gastric vein.

The true incidence of total anomalous pulmonary venous return with associated gastrointestinal varices is unknown. Echocardiography is not sensitive for the detection of gastrointestinal varices. The urgency of corrective surgical intervention might not allow for the varices to manifest clinically. The described cases of catastrophic gastrointestinal tract haemorrhage associated with total anomalous pulmonary venous return were mainly in the pre-operative period.

Echocardiography is the current diagnostic modality of choice. However, should there be any question regarding heterotaxy, location, or size of the pulmonary veins, then pre-operative CT angiography of the chest and upper abdomen will provide accurate high-resolution imaging to guide the surgery.