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Key Concepts

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  • Epidemiology

    • Truncus arteriosus is a rare cyanotic cardiac malformation with an incidence of 0.07 per 1000 live births (1.1 percent of all cardiac anomalies), with 40 percent of patients disclosing 22q11 deletion on genetic testing. There is also a variable phenotypic association with DiGeorge syndrome and craniofacial defects.

  • Morphology

    • A single truncal valve usually overrides a large ventricular septal defect. The different classification schemes are based on the origin of the pulmonary arteries (PAs) (from truncus, ductus arteriosus, or descending aorta), the association of aortic arch interruption, and ventricular septal defects.

  • Pathophysiology

    • Typically, there is intracardiac mixing (atrial and/or ventricular septal defect) with pulmonary over-circulation and, if interrupted aortic arch (IAA) is present, features of duct-dependent distal aortic perfusion. If untreated, chronic pulmonary vascular changes ensue, leading to fixed pulmonary hypertension.

  • Clinical features

    • Presentation is in the neonatal period with pulmonary over-circulation and worsening symptoms as pulmonary vascular resistance falls. Hemodynamic collapse, acidosis, and lower body malperfusion are seen in patients with associated IAA and closure of the patent ductus arteriosus.

  • Diagnosis

    • Echocardiography is usually all that is needed to proceed to surgical correction. Truncal anatomy, truncal valve morphology and function, location of the ventricular septal defect, and coronary anatomy are usually well defined echocardiographically. Additional diagnostic modalities include cardiac catheterization, computed tomography, and magnetic resonance imaging with three-dimensional reconstruction.

  • Treatment

    • Complete repair in the neonatal period is standard treatment, following resuscitation and prostaglandin (PGE1) infusion in newborns with IAA and ductal closure. Repair entails closure of the ventricular septal defect, truncal septation with reestablishment of continuity from the right ventricle (RV) to the PA with a valved conduit, and, if required, IAA and truncal valve repair. PA banding is currently very rarely performed in neonates and infants, in whom complete correction is contraindicated.

  • Outcomes

    • In contemporary series, operative mortality ranges between 4 and 7 percent and is correlated to the reactivity of the pulmonary vascular bed and operative weight below 3 kg. Long-term prognosis is dependent on need for reintervention for truncal valve repair/replacement and structural failure of the RV-PA conduit.

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History and Epidemiology

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Truncus arteriosus (also termed common arterial trunk) is an unusual14 developmental anomaly, characterized by incomplete conotruncal septation, leading to a common aortopulmonary trunk and ventricular septal defect. The disorder was first described by Wilson in 1798.5 Initial surgical management consisted of palliative pulmonary artery (PA) banding; however, long-term survival associated with this treatment was poor. The first surgical repair was performed in 1962, when Behrendt and colleagues closed the ventricular septal defect and used a valveless conduit to establish continuity between the right ventricle (RV) and the PA.6 Complete repair of truncus arteriosus with a valved conduit was first reported by McGoon in 19677 and remains the procedure of choice for the majority of patients.

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A recent prospective population-based study estimated the prevalence of truncus arteriosus to be ...

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