Truncus Arteriosus
Definition
The coronary arteries, main pulmonary artery, and aortic arch all arise from a common trunk
Types
- 1: main pulmonary artery arises from the truncal root
- II: each pulmonary artery arises directly from the posterior portion of the truncal root as separate vessels with separate orifices
- III: each pulmonary artery arises directly from the lateral aspects of the truncal root as separate vessels with separate orifices
Associated Anomalies
- Ventricular septal defect (100%)
- Right aortic arch (30 to 50%)
- Atresia of ductus arteriosus
- Truncal valve regurgitation
- Coronary artery anomalies
- Atrial septal defect
Cardiac Auscultation
- Loud, constant systolic click
- Single second heart sound
- Systolic murmur with a thrill at the third and fourth intercostals spaces
- Diastolic decrescendo murmur due to truncal valvular regurgitation
Electrocardiogram
- Biatrial enlargement
- Biventricular enlargement
Chest X-ray
- Right aortic arch (30 to 50%)
- Cardiomegaly
Surgical Treatment
- Pulmonary arteries are excised and the defect closed
- Ventricular septal defect closed
- Dacron conduit with a valve is attached to the pulmonary Artery and to the right ventricle
M-mode
- Limited
2-D
- Parasternal long-axis demonstrates the large overriding truncal root and ventricular septal defect
- Parasternal short-axis of the aortic valve demonstrate the large truncus, the number of valve leaflets (usually three) with the absence of main pulmonary artery in its usual location. The truncal root should be examined in this view for the pulmonary arteries.
Doppler
- Evaluate truncal valve insufficiency or stenosis