VENTRICULAR DISCREPANCY AS A SONOGRAPHIC SIGN OF COARCTATION OF THE FETAL AORTA - HOW RELIABLE IS IT

The purpose of this study was to assess the predictive value and sensi tivity of discrepant ventricular size for fetal aortic coarctation. Po stnatal follow-up data were obtained in 42 fetuses in whom ventricular size discrepancy (left ventricle smaller than right ventricle) was re cognized on an obstetrical sonogram. Additionally, from postnatal reco rds, we identified infants with coarctation who had had an obstetrical sonogram after 16 weeks. Fourteen of the 42 fetuses had coarctation o r other aortic arch obstruction after birth (33% positive predictive v alue). Eight (62%) of 13 fetuses with ventricular discrepancy recogniz ed before 34 weeks had coarctation, compared with six (21%) true posit ive cases among 29 recognized after 34 weeks (P = 0.01, Fisher's exact test). Of 21 infants with coarctation, ventricular discrepancy had be en recognized by prenatal sonography in 13 (62% sensitivity). Ventricu lar discrepancy has moderate sensitivity and mediocre positive predict ive value for coarctation. The limitations of this finding for diagnos ing coarctation, particularly a higher false positive rate after 34 we eks, must be recognized, but it is still a useful sign to identify thi s potentially ductus-dependent lesion.