Rare Association Between Atrioventricular Septal Defect and Partial Anomalous Pulmonary Venous Connection

Clinical data Infant, 7 months, female, referred to our department at one month of age, suspecting of congenital heart disease for further investigation. Chest radiography Demonstrates cardiomegaly and prominent pulmonary vascular markings. Electrocardiography Shows right ventricular hypertrophy and left anterior fascicular block. Echocardiography Evidenced common atrioventricular valve with two orifices and the left superior pulmonary vein draining on the brachiocephalic vein. Computed tomography angiography This complementary imaging exam was performed to confirm the diagnosis. Diagnosis The patient presented an association between AVSD and PAPVC, a rare combination. The clinical picture of heart failure was preponderant, characterized by need for diuretics and complementary exams findings, and early surgical treatment was indicated. Operation The operation was performed through a median sternotomy with 123 minutes of cardiopulmonary bypass and 89 minutes of cross-clamping time. The patient had no postoperative complications, remaining 10 days hospitalized.

During outpatient follow-up, presented with dyspnea on exertion, therefore, diuretics were initiated. At 7 months of age, surgical repair was indicated.

Chest Radiography
Posterior-anterior chest radiography shows increased pulmonary vascular markings, more prominent in the upper lungs. Enlarged cardiac area with a cardiothoracic ratio of 0.63 ( Figure 1).

Echocardiography
Situs solitus in levocardia. Abnormal venoatrial and atrioventricular connection and normal ventriculoarterial connection.  Doppler examination demonstrated presence of atrial septal defect (5 mm) with left-to-right shunt and ventricular septal defect (2 mm).
Common atrioventricular valve with two orifices, characterizing a transitional atrioventricular septal defect.
Left superior pulmonary vein draining on the brachiocephalic vein, typical of partial anomalous pulmonary venous connection (PAPVC).
To confirm the diagnosis, the patient underwent a complementary imaging examination.

Computed tomography angiography
Atrioventricular septal defect (AVSD) showing signs of right chamber, pulmonary trunk and left pulmonary artery dilatation. Partial anomalous pulmonary venous return from the upper left lobe in the brachiocephalic vein, as shown in Figure 3. AVSD represents approximately 4% of all cardiac malformations and total anomalous pulmonary venous connection (TAPVC) corresponds to 0.8% of all congenital heart diseases [1] . PAPVC was observed in 0.6% to 0.7% of autopsies [2] . Presence of left-sided PAPVC is described only in 7% of cases in a series of 236 patients [2] . Of the 132 patients who underwent repair of partial AVSD, 62 were associated with other heart defects and the association with PAPVC was not found [3] . Another study described an association between anomalous pulmonary venous return and AVSD in 7% of patients [4] .
Clinical presentation depends on the type of AVSD. Due to leftto-right shunt at both atrial and ventricular level in complete AVSD and atrioventricular (AV) valve regurgitation, children will develop congestive heart failure [5] . Patients with partial AVSD can remain asymptomatic for years.
In this case, the clinical picture of heart failure was preponderant, characterized by need for diuretics and findings of complementary exams.
The echocardiogram performed by an experienced professional was fundamental to identify one of the pulmonary veins connecting anomalously to the brachiocephalic vein and not to the left atrium, which was confirmed by angiography ( Figure 3). Computed tomography angiography is the gold standard for the diagnosis of PAPVC and can also evaluate postoperative complications, as demonstrated by Croti et al [6] .
The patient presented with a small ventricular septal defect and should have little hemodynamic repercussion, but due to the presence of the anomalous left superior pulmonary vein connection, a greater right-side overload and increased pulmonary flow were observed, and early surgical treatment was indicated. The operation was performed through a median sternotomy with partial thymus resection (left). Heparinization with 4 mg/kg and careful cannulation of the aorta and bicaval were performed as routine. Hypothermia at 28º Celsius with 123 minutes of cardiopulmonary bypass and 89 minutes of cross-clamping time.
Dissection of left superior pulmonary vein with drainage in the brachiocephalic vein. During dissection, a small intercostal systemic vein was found draining into the pulmonary vein, as shown in angiography ( Figure 3B). Ligature and excision of the intercostal vein was performed. Opening on the anterior wall of the pulmonary vein and left atrial appendage and continuous suture with polydioxanone 7-0 between structures (Figure 4).
A common atrioventricular valve with two orifices and a cleft in left AV valve were found. Ventricular septal defect was singlesutured with pledgets, and the cleft in the left AV valve was closed using 6-0 polypropylene sutures. For the atrial septal defect correction, a bovine pericardium patch was used as usual. The patient had no postoperative complications, remaining 10 days hospitalized, including 6 days in a pediatric cardiac care unit and 4 days in the pediatric ward.

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No financial support. No conflict of interest.