Abnormal Total Pulmonary Venous Returns (TAPVR) are heart defects characterized by a lack of abnormal communication between the pulmonary veins and the left atrium . Four types have been decreased, including the supracardiac type representing 45 to 55% of cases . The clinical presentation is polymorphous and the obstruction of the pulmonary veins makes this diagnosis a real emergency. Imaging has a crucial place in the diagnosis of these abnormalities. Through this presentation, we review the clinical, radiological and therapeutic data of this rare infant entity.
This is a 1-year-old male infant from a triplet pregnancy with a history of frequent respiratory infections who presents with tachypnea and retarded weight growth. The standard X-ray did not find any parenchymal opacity, but rather an enlarged mediastinum giving the appearance of a figure 8 of a snowman (Figure 1). Echocardiography revealed a suspicious venous return abnormality. Chest CT angiography revealed that the pulmonary veins drained via a posterior common manifold, running upwards on the left side and draining into the ipsilateral innominate vein and then into the superior vena cava on the right side (Figure 2). This anomaly was associated with cardiomegaly, atrial septal defect (ASD) (Figure 3) and pulmonary arterial hypertension (PAH). In addition, ventricular septal defect (VSD) is present, with left-to-right shunts between the manifold and the pulmonary artery, as well as between the manifold and the descending aorta.
The patient underwent reconstructive surgery with simple, uneventful postoperative course. Imaging was performed one year after the operation, and did not report any significant abnormality.
Total Abnormal Pulmonary Venous Return (ARVPA) is a congenital heart condition that accounts for approximately 2% of all congenital heart defects. It is often associated with other heart defects, including atrial septal defect (ASD), although it can also present in isolation .
There are several types of RVPAT [4,5]:
- Type I, called supracardiac, where the pulmonary veins flow into a common collector located behind the left atrium, then drain into the left innominate trunk via a vertical vein. In rare cases, drainage may be into the right superior vena cava or the greater azygos vein.
- Type II, called cardiac, where the pulmonary veins drain directly into the right atrium or indirectly through an enlarged coronary sinus.
- Type III, called infracardiac, where the pulmonary veins drain through the diaphragm into the portal trunk or into the inferior vena cava.
- Type IV, called mixed, has characteristics combining different types of RVPAT.
The clinical presentation of RVPAT may vary depending on the specific type of malformation and whether or not an obstruction is present. If obstructed, symptoms may include difficulty breathing, cyanosis, and heart failure .
On radiographic examination of the thorax, dilatation of the supracardiac venous loop is often observed, with a dilated left ascending vein and a dilated superior vena cava on the right, giving a characteristic appearance of a "figure-8 mediastinum" or a snowman".
Cardiac ultrasound is a diagnostic tool that can evoke the diagnosis of RVPAT, but generally does not allow the malformation to be precisely located. The classic signs observed are an asymmetry of the heart chambers with a predominance on the right side, a small and rounded left atrium, a large distance between the left atrium and the descending aorta, the absence of an abutment of the pulmonary veins in the left atrium, or even the absence of flow from the pulmonary veins in the left atrium detectable by color Doppler. Ultrasound can also directly show the image of the pulmonary vein collector located in the retroauricular position, as well as an interatrial communication (ASD) [4,6].
Thoracic CT angiography occupies an important place in the evaluation of RVPAT, although it involves exposure to ionizing radiation. It provides a complete anatomical view of the pulmonary and cardiovascular structures. CT angiography confirms the diagnosis by visualizing the pulmonary vein collector, and it shows the course and orientation of the abnormal drainage vein. She also looks for possible compressions in the course of the pulmonary veins, such as compression between the left mainstem bronchus and the pulmonary artery in the case of left type I, or compression between the aorta and the atrium, or at the diaphragm level for Type III. However, CT angiography provides little [1,5-7].
Magnetic resonance imaging (MRI) also offers a full anatomical assessment of RVPAT, providing additional information about associated visceral and cardiac malformations. In some patients, MRI may produce clearer images than echocardiography or angiography, especially to assess sites of connection and stenosis .
CT angiography is still considered the reference (gold standard) in the diagnosis of RVPAT, but it is difficult to perform in young children because of their unstable clinical condition, which limits its use..
The need for cardiac catheterization in the case of a diagnosis of RVPAT is controversial. Some medical teams perform catheterization only in cases of mixed forms of RVPAT or when echocardiography is difficult to interpret, in an attempt to reduce the risks associated with surgery. Other studies suggest that cardiac catheterization poses risks, especially taking into account the unstable clinical state of patients when this pathology is discovered [6,8].
The treatment is surgical, with a restorative aim and its various techniques continue to improve in order to make it possible to lengthen survival and reduce mortality.
Due to the rarity of RVPAT and the absence of specific symptoms, medical imaging is of paramount importance in the exploration and diagnosis of this pathology. Echocardiography, CT angiography, and cardiac MRI provide accurate and detailed images of heart and vascular structures, which help doctors confirm the diagnosis of RVPAT and plan appropriate treatment.
Conflicts of Interest
The authors declare no conflicts.