We report a rare case of a neonate with interrupted aortic arch, aortopulmonary window and complete atrioventricular septal defect. To the best of our knowledge, this unusual triad has not been previously described. The main question of the surgical strategy for CAVSD, in setting of associated defects, is to classify the CAVSD as balanced or unbalanced.

Key words: Aortopulmonary window, Complete atrioventricular septal defect, Interrupted aortic arch.

Echocardiogram revealed situs solitus, atrioventricular and ventriculoarterial concordance. The left-sided superior caval vein drained to the right atrium via enlarged coronary sinus. Right ventricle was well developed, and left ventricle was border sized with AV valve index (left AV valve/total AV valve area) estimated as 0.4. There was a huge CAVSD with single left antero-laterally papillary muscle and common atriventricular valve attached to the crest of the ventricular septum by chordae (Fig. 1a). Color Doppler demonstrated moderate regurgitation on the atrioventricular valve. The large aortopulmonary communication was observed just above tricuspid and nonstenotic aortic valve (APW- type 1). The relatively small ascending aorta was giving rise right and left common carotid arteries. The left subclavian artery was noticed arising from descending aorta just before the patent ductus arteriosus (IAA – type B) (Fig. 1b).

Fig. 1 (a) The defect in the aortopulmonary septum was seen in parasternal short-axis. Two separate aortic and pulmonary valve were present. Ao-aorta; AP-pulmonary artery; APW-aortopulmonary window. (b) Suprasternal long-axis view demonstrated the interruption of the aortic arch between left common carotid and left subclavian artery. Ao asc-ascending aorta; Ao desc-descending aorta; IAA-interrupted aortic arch.

Post sternotomy, a hypoplastic and poorly ventilated left lung was immediately noted, which did not respond adequately to manual hyperventilation. Left persistent superior caval vein was dominant. Aortic arch was interrupted after the left carotid artery. Resection of ductus arteriosus and ligation of the left subclavian artery was performed in deep hypothermic cardiopulmonary bypass with mobilization of the descending aorta. The APW was 10 mm in diameter. A transection of the APW was done and the descending aorta anastomosed directly to the aortic part of the APW. The pulmonary artery was reconstructed with autologous pericardium. Cardio-pulmonary bypass was reinstituted. Due to the border sized left ventricle, we decided to delay the complete repair of the CAVSD. After the first cessation of the cardiopulmonary bypass and initial promising hemodynamics with moderate inotropic support of 10 µg/kg/min of dopamine, the child developed sudden pulmonary edema with severe blood stasis in the left lung. Reinstitution of cardiopulmonary bypass and prolonged circulatory support gave no effect. Low cardiac output and severe left lung blood stasis led to the lethal outcome. The diagnosis was re-confirmed after autopsy.

The associations between IAA and CAVSD, as well as between APW and CAVSD were reported previously [1,2]. IAA is present in approximately 1.3% and APW in only 0.2% of patients with congenital heart disease [3-5]. CAVSD comprises 5%-8% of all congenital heart defects and most frequently is associated with trisomy 21, but there is considerable evidence of genetic heterogeneity.

Sporadic reports of surgical treatment of IAA and APW with successful results have been reported in the literature [6,7]. In our case, the complex lesions of the great arteries was complicated by intracardiac finding of a CAVSD with a single papillary muscle in the left ventricle and intraoperative finding of a very poorly ventilated hypoplastic left lung. Although a satisfactory repair of the arch and the aortopulmonary window was obtained with a minimal gradient across the aortic anastomosis of 8 mmHg, the intraoperative decision to go for a staged approach rather than attempt to correct the CAVSD in the same procedure was made [8].

As echocardiographic AV valve index was borderline, our patient could not be clearly classified as unbalanced or balanced [9]. The decision for a staged approach was made based on the facts that there was a high probability of an unbalanced left ventricle with paraschute deformity of the left sided atriventricular valve and that a univentricular repair would be a more probable option. The great concern was the poorly developed and ventilated left lung, technical challenges for the surgeon and associated anomalies (IAA, APW).

Although there are no established guidelines in unbalanced CAVSD for deciding between biventricular or univentricular repair, AV valve index could effectively characterizes the anatomic substrate and selects surgical strategy [9,10]. The main item of the operative strategy for CAVSD, in setting of great arteries anomalies, is to classify the CAVSD as balanced or unbalanced.

Contributors: All persons designated as authors qualified for the authorship. They reached authorship credit by contributions in concept, design and article drafting. Also they helped with final approval of the version to be published.

Funding: None; Competing interests: None stated.

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