Supracardiac total anomalous pulmonary venous return: A rare cause of congestive heart failure in the newborn

A full-term newborn male presented to the intensive care unit of the pediatric hospital for tachypnea, hypoxemia (requiring oxygen therapy) and cyanosis.

Chest radiography showed pulmonary oedema and cardiomegaly (Figure 1).

Thoracic CT angiography scan showed the two left pulmonary veins, along with the right inferior pulmonary vein draining into a common confluent (cardinal vein) (Figure 2a), which in turn extends superiorly and to the right of the heart before draining perpendicularly in the arch of the azygos vein (Figure 2b). The right superior pulmonary vein drains alone into the distal segment of the cardinal vein, near its termination in the azygos vein (Figure 2c). These findings reflect a supracardiac (type I) total anomalous pulmonary venous return (TAPVR).

A large atrial septal defect (ASD) is present and functions as a right-to-left shunt (necessary for survival in these newborns) (Figure 3).

The newborn underwent partial surgical correction of the TAPVR with the establishment of a connection between the pulmonary veins and the left atrium, but without ligation of the cardinal vein, which maintained patency to the arch of the azygos vein. The CIA was also closed. Despite the surgery, the newborn maintained heart failure, which led to the subsequent closure of the arch of the azygos vein with a vascular plug. After these procedures, the newborn showed progressive clinical improvement and was discharged from hospital.

Total anomalous pulmonary venous return (TAPVR) accounts for approximately 1–5% of congenital heart anomalies (CHAs) [1-3]. This condition is a cause of neonatal cyanosis and may rapidly result in death when blood is not shunted from the right heart (or pulmonary circulation) to the left heart (or systemic circulation). This shunting typically occurs through either an atrial septal defect (ASD)/patent foramen ovale or, less commonly, a patent ductus arteriosus [2]. An increased frequency of TAPVR is seen in patients with heterotaxy syndromes, particularly asplenia [1,3].

The normal pulmonary venous system consists of right and left pairs of pulmonary veins (PVs) delivering the blood from both lungs to the left atrium (LA). In patients with TAPVR, the anomalous veins either directly empty into the right atrium (RA) of the heart or empty through other routes of systemic venous return [4].

Several classification systems based on anatomy, physiology, or perinatal outcomes exist. The most commonly used is the Darling classification, first introduced in 1957 [5]. TAPVR is classified into four categories according to where the abnormal connection occurs:

• Type I: Supracardiac type, which is the most common type. The entrance of the pulmonary blood flow into the systemic venous system is cranial to the RA. This accounts for 45–55% of TAPVR cases, in which the confluent vessel usually empties into the brachiocephalic vein, superior vena cava, or azygos vein [3,6].
• Type II: Cardiac type, which is diagnosed when the PVs converge on a confluent vessel and then horizontally connect to the RA through the coronary sinus or at the posterior wall of the RA. Approximately 20–30% of TAPVR patients exhibit the cardiac type [4].
• Type III: Infracardiac type. The PVs conjoin and form a vertical vessel that travels caudally into the portal vein or its branches, such as the ductus venosus, hepatic vein, and inferior vena cava. This type accounts for 13–25% of cases [4].
• Type IV: Mixed type. Less than 10% patients belong to this subtype, in which the right and left pulmonary tributaries drain at two or more different levels [7].

Echocardiography is the initial imaging technique of choice in the evaluation of CHAs, including pulmonary venous anomalies [8,9]. Although echocardiography has a variety of strengths, including portability and lack of ionizing radiation, evaluation of pulmonary veins may be suboptimal in some patients.

MRI is the preferred imaging technique for the evaluation of pulmonary venous structures after echocardiography. MRI can be used to depict complex thoracic cardiovascular anomalies, including pulmonary vein abnormalities [1,8–12]. Advantages of this imaging technique include a lack of ionizing radiation, multiplanar capability, and the ability to acquire multiple imaging phases using a single IV bolus of gadolinium-containing contrast material. Disadvantages of MRI include the amount of time required for image acquisition, the frequent need for patient sedation, and its susceptibility to metal-related artefacts [13].

CT excellently depicts anomalous pulmonary venous structures with detection rates that approach 100% [14]. The primary disadvantage of CT is that it requires the use of ionizing radiation. CT also requires the use of IV iodinated contrast material, which may adversely affect renal function or, rarely, result in acute allergic-like reactions, as well as the need to sedate the patient. CT may be useful for imaging pulmonary venous structures in patients who are incompletely evaluated by echocardiography and who cannot, for whatever reason, undergo an MRI examination [13]. For patients with suspected TAPVR, as well as for small children, cardiac gating is not required for the evaluation of pulmonary venous structures [13]. In the authors' opinion, CT, as it provides information similar to MRI and because it is a more accessible and less expensive method, is the best imaging modality in the preoperative evaluation of these patients.

TAPVR is a defect that needs surgery to fix. The surgical repair connects all of the veins to the back of the left atrium. This leads to a normal connection of pulmonary veins to left atrium. All other routes for pulmonary venous drainage are tied off. Finally, the ASD is also closed. Long-term outcome is excellent after repair, with 5-year survival rates of up to 97% [15].

Take Home Message / Teaching Points

Anomalous Pulmonary Vein Return (total or partial) comprise a wide spectrum of congenital heart diseases.

Newborns can present with non-specific signs and symptoms such as respiratory distress, cyanosis, and feeding intolerance, which is why a high index of suspicion is necessary for the prompt diagnosis and evaluation of these patients.

In cross-sectional imaging, failure to identify a normal PV connection and a demonstration of the vertical vein and confluent vessel are essential for a confirmation of the diagnosis.

All patient data have been completely anonymised throughout the entire manuscript and related files.