Persistent truncus arteriosus
Persistent Truncus Arteriosus
Classification & 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.
Persistent truncus arteriosus (or Truncus arteriosus) is a rare form of congenital heart disease that presents at birth. In this condition, the embryological structure known as the truncus arteriosus never properly divides into the pulmonary artery and aorta.
The most well-known classification was the fourfold system developed by Collett and Edwards in 1949. Collett/Edwards Types I, II, and III are distinguished by the branching pattern of the pulmonary arteries:
- Type I: truncus -> one pulmonary artery -> two lateral pulmonary arteries
- Type II: truncus -> two posterior/posterolateral pulmonary arteries
- Type III: truncus -> two lateral pulmonary arteries
The "Type IV" proposed in 1949 is no longer considered a form of PTA by most modern sources.
Another well-known classification was defined by Van Praaghs in 1965.
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. The neural crest, specifically a population known as the cardiac neural crest, directly contributes to the aorticopulmonary septum. 
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.  
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. 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).
- ^ Collett RW, Edwards JE: Persistent truncus arteriosus: a classification according to anatomic types. Surg Clin North Am 1949; 29: 1245-70.
- ^ Persistent Truncus Arteriosus: Congenital Cardiovascular Anomalies: Merck Manual Professional. Retrieved on 2007-11-04.
- ^ a b c eMedicine - Truncus Arteriosus : Article by Doff McElhinney, MD. Retrieved on 2007-11-04.
- ^ Van Praagh R, Van Praagh S (1965). "The anatomy of common aorticopulmonary trunk (truncus arteriosus communis) and its embryologic implications. A study of 57 necropsy cases". Am. J. Cardiol. 16 (3): 406–25. PMID 5828135.
- ^ Kirby ML, Gale TF, and Stewart DE. (1983). "Neural crest cells contribute to normal aorticopulmonary septation.". Science 220 (4061): 1059-61. PMID 6844926.
- ^ Jiang X, Rowitch DH, Soriano P, McMahon AP, Sucov HM.. (2000). "Fate of the mammalian cardiac neural crest...journal = Development." 127 (8): 1607-16. PMID 10725237.
- ^ Hutson MR, Kirby ML.. (2003). "Neural crest and cardiovascular development: a 20-year perspective.". Birth Defects Res C Embryo Today. 69 (1): 2-13. PMID 12768653.
- ^ Waller BR 3rd, McQuinn T, Phelps AL, Markwald RR, Lo CW, Thompson RP, Wessels A. (2000). "Conotruncal anomalies in the trisomy 16 mouse: an immunohistochemical analysis with emphasis on the involvement of the neural crest.". Anat. Rec. 260 (3): 279-93. PMID 11066038.
- ^ Franz T. (1989). "Persistent truncus arteriosus in the Splotch mutant mouse.". Anat. Embryol. (Berlin). 180 (5): 457-64. PMID 2619088.
- ^ Rodefeld M, Hanley F. "Neonatal truncus arteriosus repair: surgical techniques and clinical management.". Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu 5: 212-7. PMID 11994881.
|Congenital malformations and deformations of circulatory system (Q20-Q28, 745-747)|
|Cardiac chambers and connections||Persistent truncus arteriosus - Double outlet right ventricle (Taussig-Bing syndrome) - Transposition of the great vessels (dextro, levo)|
|Cardiac septa||Ventricular septal defect - Atrial septal defect (Lutembacher's syndrome) - Atrioventricular septal defect (Ostium primum) - Tetralogy of Fallot - Eisenmenger's syndrome|
|Right: pulmonary and tricuspid valves||pulmonary valves (stenosis, insufficiency) - tricuspid valves (stenosis, atresia) - Ebstein's anomaly|
|Left: aortic and mitral valves||aortic valves (stenosis, insufficiency, bicuspid) - mitral valves (stenosis, regurgitation) - Hypoplastic left heart syndrome|
|Other congenital malformations|
|Dextrocardia - Levocardia - Cor triatriatum|
|Great arteries||aorta (Patent ductus arteriosus, Aortic coarctation, Interrupted aortic arch, Overriding aorta, Aneurysm of sinus of Valsalva, Vascular ring) - Pulmonary atresia|
|Great veins||Persistent left superior vena cava - Total anomalous pulmonary venous connection - Scimitar syndrome|
|Other||Arteriovenous malformation (Cerebral arteriovenous malformation)|
|See also non-congenital conditions (I, 390-459)|