title: Incidence of an Aberrant Right Subclavian Artery on Second-Trimester Sonography in an Unselected Population.
abstract: OBJECTIVE
  The aim of this study was to assess the incidence of an aberrant right subclavian artery (ARSA) among an unselected population during second-trimester sonography and to review the importance of this conotruncal variant as a marker of Down syndrome.
  
  
  METHODS
  The presence or absence of an ARSA was assessed in an unselected population of 1913 second-trimester fetuses.
  
  
  RESULTS
  Among the 1913 patients, an ARSA was detected in 20 fetuses (1.04%), all with a normal karyotype. Thirteen of 20 fetuses had an isolated ARSA, and 7 of them were nonisolated. Associated abnormal sonographic findings were an intracardiac echogenic focus (n = 3), a choroid plexus cyst (n = 1), pyelectasis (n = 1) and tetralogy of Fallot (n = 2). One of the cases of tetralogy of Fallot was also associated with a persistent left superior vena cava, a persistent right umbilical vein, hydrocephalus, rhombencephalosynapsis, and unilateral renal agenesis. There were only 2 fetuses with Down syndrome in this group, and both of them had a normal origin of the right subclavian artery.
  
  
  CONCLUSIONS
  In an unselected population, an ARSA may be seen less frequently than in a high-risk population and may not be related to Down syndrome. An isolated ARSA is not a sufficient indication for karyotype analysis; it can be managed with noninvasive prenatal testing rather than invasive testing.
authors.affiliation: Department of Obstetrics and Gynecology, Isparta Egirdir Bone Joint Disease and Rehabilitation Hospital, Isparta, Turkey.
authors.forename: Selen
authors.initials: S
authors.lastname: Gursoy Erzincan
authors.affiliation: Cayeli State Hospital, Rize, Turkey.
authors.forename: Burcin
authors.initials: B
authors.lastname: Karamustafaoglu Balci
authors.affiliation: Department of Obstetrics and Gynecology, Bilge Hospital, Istanbul, Turkey.
authors.forename: Cengiz
authors.initials: C
authors.lastname: Tokgoz
authors.affiliation: Department of Obstetrics and Gynecology, Istanbul University, Istanbul Faculty of Medicine, Istanbul, Turkey.
authors.forename: Ibrahim Halil
authors.initials: IH
authors.lastname: Kalelioglu
mesh_terms: D000293:Adolescent; D000328:Adult; D000783:Aneurysm / Q000150:complications* / Q000000981:diagnostic imaging* / Q000196:embryology; D018376:Cardiovascular Abnormalities / Q000150:complications* / Q000000981:diagnostic imaging* / Q000196:embryology; D004314:Down Syndrome / Q000150:complications*; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D012189:Retrospective Studies; D013348:Subclavian Artery / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000196:embryology; D014421:Turkey; D016216:Ultrasonography, Prenatal / Q000379:methods*; D055815:Young Adult
keywords: aberrant right subclavian artery; marker; obstetric ultrasound; prenatal diagnosis; trisomy 21