Aberrant right subclavian artery (ARSA):

  • ARSA occurs in ~1% of the normal population and is regarded as a benign condition. No treatment is usually required as most affected individuals are asymptomatic. However, very rarely, there might be compression of the ARSA onto the oesophagus causing dysphagia, in which case, surgical treatment will be needed;
  • ARSA might be associated with other cardiac abnormalities, in particular conotruncal defects. There is a also reported association with chromosomal and genetic aberration, in particular trisomy 21 (Downs syndrome). With isolated ARSA (i.e. absence of other Downs markers), there is a 3.9 times increase in risk. The other chromosomal and genetic aberrations associated include trisomy 13 and 18, and Di George syndrome (22q11.2 microdeletion);
  • A detailed fetal morphology scan is advised to look out for other structural defect(s) in particular, congenital cardiac abnormalities and ultrasound markers for chromosomal aberration;
  • Counselling on the pros and limitation of NIPT and the pros and risks of an amniocentesis is also recommended.
This article is contributed by Dr. T.N. Danny Leung
updated on 25.09.2020