Diagnostic yield from routine visualisation of Bi-subclavian view, and axial three vessel trachea view, during fetal cardiac evaluation in non-referral antenatal women Authors: Seneesh KV, Bijoy B, Meenu B, Sreeja PS, Swapneel NP, Gopinathan KK Institution(s): CIMAR Edappal, Edappal Hospital pvt ltd Abstract No: 0248 Results Introduction The routine axial views obtained during fetal cardiac evaluation in prenatal ultrasound includes, from caudo-cranial direction - fetal abdomen at the level of abdominal circumference plane, four chamber view, three vessel view and finally transverse aortic arch view. However the caudo-cranial sweep can be extended further to include the three vessel trachea (3VT), and Bi subclavian views, under color Doppler mapping. These views needs to be evaluated for their benefits. Aberrant right subclavian artery (ARSA) with left aortic arch was diagnosed in 9 cases (9/2000, 0.45 %) Right aortic arch (RAA) was observed in 5 cases (5/2000, 0.25 % cases) In 8 cases, ARSA was isolated (89%) In one case of ARSA, Down syndrome was detected after Karyotype. This case had additional absent nasal bone, increased NT in first trimester, hyperechoeic bowel All cases of RAA were isolated Isolated cases of ARSA, and all cases of RAA were negative for 22q11 microdeletion Down syndrome was seen additionally in 3 more case (4/2000, 0.2 %) Cardiac anomalies were noted in 9 cases (incidence 0.45 %), overall major anomalies were noted in 1.6 % of cases No association of ARSA and RAA with cardiac or extra cardiac anomalies were observed Diagnostic performance of ARSA- (sensitivity-25%, specificity- 99.6%, positive likelihood ratio - 62.5 %, negative likelihood ratio- 0.75 %; Odds ratio- 82.8%, 95% CI=7.8-88) However +LR of isolated ARSA was nil Aim / Objectives To evaluate the clinical yield, in terms of aberrant vessels, chromosomal abnormalities and congenital malformations, by the routine inspection of three vessel trachea and Bisubclavian views, under color Doppler, in non referral antenatal women Materials & Methods This was a prospective study involving 2000 non referral antenatal women, recruited consecutively, from February 2015 to January 2016, attending the Fetal medicine unit of Edappal hospital, and undergoing delivery at the same institute. Approval from institutional ethics board and individual consents were obtained. All case diagnosed with aberrant vessels underwent karyotyping and testing for monosomy 22q11.2 microdeletion. USG settings- Voluson E8, abdominal transducer 1-5 MHz ; PRF 1.2-2.5 KHz for color flow imaging Abbrev RAA-right aortic arch, RSA-right subclavian A, LSA- Left subclavian A MPA- Main Pulmonary A, Ao -Aorta References Chaoui R. Prenatal ultrasound diagnosis of Down syndrome. After major malformations, soft markers, nuchal translucency and skeletal signs, a new vascular sign?. Ultrasound Obstet Gynecol.2005; 26: 214-17. Yoo SJ, Min JY, Lee YH, Roman K, Jaeggi E, Smallhorn J. Fetal sonographic diagnosis of aortic arch anomalies. Ultrasound Obstet Gynecol. 2003; 22: 535– 46. Bravo C, Gámez F, Pérez R, Álvarez T.Juan De León-Luis. Fetal Aortic Arch Anomalies-Key Sonographic Views for Their Differential Diagnosis and Clinical Implications Using the Cardiovascular System Sonographic Evaluation Protocol. J Ultrasound Med. 2016; 35: 237–51 Scala C, Leone Roberti Maggiore U, Candiani M, Venturini PL, Ferrero S, Greco T, et al. Aberrant right subclavian artery in fetuses with Down syndrome: a systematic review and meta-analysis. Ultrasound Obstet Gynecol.2015; 46: 266-76. Conclusion The three vessel view and Bisubclavian views under color Doppler, can be obtained with ease after supervised training Prognostically significant diagnostic yield in non referral population, however, seems to be uncertain Karyotype in isolated cases seems to be unwarranted Isolated cases have normal neonatal outcomes The duration of fetal cardiac evaluation is prolonged by including these extra views Large prospective studies are required for further validation of these observations