| Persistent Truncus Arteriosus | |
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| Classification and external resources | |
Diagrams to illustrate the transformation of the bulbus cordis. Ao. Truncus arteriosus. Au. Atrium. B. Bulbus cordis. RV. Right ventricle. LV. Left ventricle. P. Pulmonary artery. |
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| ICD-10 | Q20.0 |
| ICD-9 | 745.0 |
| OMIM | 217095 |
| DiseasesDB | 32081 |
| MedlinePlus | 001111 |
| eMedicine | ped/2316 |
| MeSH | D014339 |
Persistent truncus arteriosus (or Truncus arteriosus), also known as Common arterial trunk, is a rare form of congenital heart disease that presents at birth. In this condition, the embryological structure known as the truncus arteriosus fails to properly divide into the pulmonary trunk and aorta.
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The most well-known classification was the fourfold system developed by Collett and Edwards in 1949.[1] Collett/Edwards Types I, II, and III are distinguished by the branching pattern of the pulmonary arteries:[2][3]
The "Type IV" proposed in 1949 is no longer considered a form of PTA by most modern sources.[3]
Another well-known classification was defined by Van Praaghs in 1965.[3][4]
Most of the time, this defect occurs spontaneously. Genetic disorders, and teratogens (viruses, metabolic imbalance, and industrial or pharmacological agents) have been associated as possible causes. Up to 50% (varies in studies) of cases are associated with chromosome 22q11 deletions (DiGeorge Syndrome). The neural crest, specifically a population known as the cardiac neural crest, directly contributes to the aorticopulmonary septum.[5][6]
Microablation of the cardiac neural crest in developing chick embryos and genetic anomalies affecting this population of cells in rodents results in persistent truncus arteriosus.[7][8][9]
Numerous perturbations affecting the cardiac neural crest have been associated with persistent truncus arteriosus, some of which include growth factors (fibroblast growth factor 8 and bone morphogenetic protein), transcription factors (T-box, Pax, Nkx2-5, GATA-6, and Forkhead), and gap junction proteins (Connexin). The cardiac neural crest also contributes the smooth muscle of the great arteries.
Anatomical changes associated with this disorder includes:
Treatment is with neonatal surgical repair.[10] The ventricular septal defect is closed with a patch. The pulmonary arteries are then detached from the common artery (truncus arteriosus) and connected to the right ventricle using a tube (a conduit or tunnel). There have been cases where the condition has not been diagnosed at birth and surgical intervention is not an option. A number of these cases have survived well into adulthood. [11]
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