Common arterial trunk – truncus arteriosus – with arch obstruction is rare and is associated with a high mortality. The association of coronary artery abnormalities, linked syndromes such as DiGeorge Syndrome (22q11 deletion) or metabolic disorders are known additional risk factor for mortality.Reference Brown, Ruzmetov, Okada, Vijay and Turrentine 1
Case report
A 6-day-old boy, born at term with low birth weight of 2.5 kg to consanguineous parents, was admitted to the intensive care unit with severe metabolic acidosis. He was dysmorphic with short neck, atypical facial appearance, ear anomaly, and borderline microcephaly.
Echocardiography revealed a common arterial trunk with interrupted aortic arch distal to the left subclavian artery (Type A). There was moderate truncal valve regurgitation and stenosis, a large outlet ventricular septal defect, a non-restrictive atrial septal defect, and a large patent ductus arteriosus, with anatomically normal exit and course of the coronary arteries (Fig 1).
The echocardiographic views of the common arterial trunk (truncus arteriosus).
Confirmatory cardiac CT scanning revealed that the main pulmonary artery bifurcated posteriorly into the right and left branches. Furthermore, the left upper pulmonary vein was seen to be connected to the superior caval vein via a vertical vein and the innominate vein (Figs 2 and 3).
The anterior and posterior CT scan views of the common arterial trunk (truncus arteriosus).
The CT scan views of partial anomalous pulmonary venous connection to the superior caval vein.
Metabolic screening revealed high levels of phenylalanine in the blood, compatible with the diagnosis of phenylketonuria. Despite maximal resuscitative efforts, the patient died on the ninth day of life without surgical intervention.
Discussion
Common arterial trunk with interrupted arch is a rare entity and has a worse outcome than with either lesion in isolation.Reference Konstantinov, Karamlou and Blackstone 2 The presence of interruption, truncal valve regurgitation, and coronary artery anomalies negatively influence the outcome.Reference Brown, Ruzmetov, Okada, Vijay and Turrentine 1 In our patient, apart from interruption, supracardiac partial anomalous pulmonary venous connection of the left upper pulmonary vein was demonstrated. To the best of our knowledge, the association of partial anomalous pulmonary venous connection together with aortic interruption has not been reported previously, although a case of total anomalous pulmonary venous connection has been reported in one series.Reference Konstantinov, Karamlou and Blackstone 2
Common arterial trunk – truncus arteriosus – is usually categorised according to the pattern of the pulmonary origin. Jacobs and Anderson stated that all hearts with common arterial trunk should be assigned to one of the two groups based on either aortic or pulmonary dominance of the common trunk.Reference Jacobs and Anderson 3 Our patient clearly had a pulmonary dominant-type truncus with aortic interruption.
The site of arch interruption is reported to be 84% between the left common carotid and subclavian artery (Type B),Reference Konstantinov, Karamlou and Blackstone 2 whereas our patient’s CT scans clearly demonstrated the much rarer type A interruption distal to the subclavian artery.
The metabolic analysis of our patient along with low birth weight, congenital heart disease, and microcephaly led us to conclude that maternal hyperphenylalaninaemia and phenylketonuria were significant metabolic risk factors, increasing the morbidity of our patient.
Conclusion
We report the unique association of the common arterial trunk with arch interruption with anomalous pulmonary venous connection. Moreover, to our knowledge, this is the first report of this association with additional phenylketonuria.
Acknowledgements
None.
Financial Support
This study received no specific grant from any funding agency, commercial, or not-for-profit sectors.
Conflicts of Interest
None.
Ethical Standards
Informed consent was taken from the parents and all procedures contributing to this work has been approved by the institutional committees of Istanbul Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Education and Research Hospital.
