Dr. Bhumika Bhagat,
BACKGROUND Cardiovascular Doppler indices have long been demonstrated to have an association with the risk of perinatal death. Recent studies have investigated whether the aortic isthmus (AoI) could contribute to the prediction of mortality.1 The isthmus, located between the origin of the left subclavian artery and the aortic end of the DA, establishes communication between the two arterial outlets that perfuse in parallel the upper and lower body of the foetus.2 Objectives of this study were to evaluate the aortic isthmus doppler changes and its utility in management of growth-restricted foetuses. MATERIALS AND METHODS Prospective observational study, recruiting 50 women with singleton pregnancy at or beyond 28 weeks of gestation presenting to the tertiary referral hospital between June 2015 to January 2016 with intra uterine growth restricted foetus based on grey scale ultrasound findings and obstetric Doppler Ultrasound showing umbilical artery pulsatility index >95th percentile. Doppler parameters of umbilical artery, middle cerebral artery and aortic isthmus were recorded and compared to the reference values. RESULTS Out of 50 IUGR foetuses, 36(72%) showed anterograde aortic isthmus net flow whereas 14 (28%) showed retrograde aortic isthmus net blood flow. Median gestational age at inclusion and at delivery was 34.5 & 35.6 weeks in anterograde blood flow group and 30 weeks & 33 weeks in retrograde blood flow group respectively. 46% of patients had pregnancy-induced hypertension. IUGR with anaemia complicating pregnancy (sickle cell anaemia & beta thalassemia trait included) was present in 6% of cases. Bad obstetric history was seen in 4%. The postnatal complications were higher in retrograde aortic isthmus net blood flow group as compared to the anterograde net blood flow group. CONCLUSION Absence/reversal of diastolic flow in Aortic Isthmus carries grave prognosis and high mortality. Doppler imaging of the aortic isthmus could be used as a screening tool in clinical surveillance of foetus with IUGR. This might be of clinical relevance in improving the detection and management of intrauterine growth restriction.
