Truncus arteriosus is a cyanotic congenital heart anomaly in which a single trunk supplies both the pulmonary and systemic circulation, instead of a separate aorta and a pulmonary trunk. It is usually classified as a conotruncal anomaly.
The estimated incidence is 1 in 10,000 births.
Patients may present with signs and symptoms of cyanosis or congestive heart failure.
There is a lack of normal separation of the embryological truncus arteriosus into a separate aorta and pulmonary trunk. This results in a single arterial vessel that originates from the heart that supplies the systemic, pulmonary and coronary circulations. It may also result in a common truncal valve which can contain 2 to 4 cusps.
Collett and Edwards system
- type I: (most common) both aorta and main pulmonary artery arise from a common trunk
- type II: pulmonary arteries arise separately from the posterior aspect of trunk, close to each other just above the truncal valve (negligible main pulmonary artery segment)
- type III: (least common) pulmonary arteries arise independently from either side of the trunk
- type IV: neither pulmonary arterial branch arising from the common trunk (pseudotruncus), currently considered a form of pulmonary atresia with a VSD
Van Praagh system
- type A1: identical to the type I of Collett and Edwards
- type A2: separate origins of the branch pulmonary arteries from the common trunk
- type A3: origin of one branch pulmonary artery (usually the right) from the common trunk, with other lung supplied either by collaterals or a pulmonary artery arising from the aortic arch
- type A4: presence of an associated interrupted aortic arch
- right sided aortic arch
- interrupted aortic arch 8
- persistence of primitive aortic arches
- DiGeorge syndrome
- CHARGE syndrome 11
However, the main pulmonary artery (arising from common trunk) may be small/unusual in position which may result in a narrow mediastinum. This along with moderate cardiomegaly and pulmonary plethora gives an appearance that is similar to D-loop transposition of great arteries 9.
Right-sided aortic arch may be seen in ~40% (range 35-50%) of cases 2,10.
Allows direct visualisation of a single trunk. Outflow tract views are the most useful. Colour Doppler may additionally show flow across both ways through an associated VSD.
Allows direct visualisation of abnormal anatomy.
Allows direct display of anomalous anatomy. SSFP cine sequences can offer an additional functional assessment.
Treatment and prognosis
Due to parallel fetal circulation, truncus arteriosus does not cause any haemodynamic problem in utero. However it is a major problem postnatally and, if left untreated, approximately 80% of infants die within the first year.
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- 6. Takaki MT, Dubinsky TJ, Warren BH et-al. Nonatherosclerotic cardiovascular findings on MDCT coronary angiography: a selection of abnormalities. AJR Am J Roentgenol. 2008;190 (4): 934-46. doi:10.2214/AJR.07.2830 - Pubmed citation
- 7. Ceballos R, Soto B, Kirklin JW et-al. Truncus arteriosus. An anatomical-angiographic study. Br Heart J. 1983;49 (6): 589-99. Br Heart J (link) - Free text at pubmed - Pubmed citation
- 8. Bohuta L, Hussein A, Fricke TA et-al. Surgical repair of truncus arteriosus associated with interrupted aortic arch: long-term outcomes. Ann. Thorac. Surg. 2011;91 (5): 1473-7. doi:10.1016/j.athoracsur.2010.12.046 - Pubmed citation
- 9. Textbook of radiology and imaging. Churchill Livingstone. ISBN:0443071098. Read it at Google Books - Find it at Amazon
- 10. Comprehensive Neonatal Care. Saunders. ISBN:1416029427. Read it at Google Books - Find it at Amazon
- 11. Perloff JK, Marelli A. Perloff's Clinical Recognition of Congenital Heart Disease. Saunders. ISBN:1437716180. Read it at Google Books - Find it at Amazon
Congenital heart disease
There is more than one way to present the variety of congenital heart diseases. Whichever way they are categorised, it is helpful to have a working understanding of normal and fetal circulation, as well as an understanding of the segmental approach to imaging in congenital heart disease.
congenital heart disease
- normal relationship between chambers and valves
- atrioventricular valves
- outflow tract
- great vessels
- venous inflow
- anomalous valves
- abnormal relationship of chambers and valves
- atrioventricular abnormality
- great vessel connection abnormality
- conotruncal cardiac anomalies
- pentalogy of Cantrell
- Shone syndrome
- congenital heart disease - chest x-ray approach
surgical repairs (mnemonic)
- arterial switch procedure
- Blalock-Taussig shunt
- double switch procedure
- Fontan procedure
- Glenn procedure
- Mustard repair
- Norwood procedure
- Pott shunt
- pulmonary artery banding
- Rastelli procedure
- Sano shunt
- Senning repair
- total repair of tetralogy of Fallot (TOF)
- unifocalisation procedure
- Waterston shunt