Correlation between ductus venosus spectrum and right ventricular diastolic function in isolated single-umbilical-artery foetus and normal foetus in third trimester

BACKGROUND Single umbilical artery(SUA)is the most common umbilical cord malformation in prenatal diagnosis.The presence of an SUA can cause blood circulation disorder in the foetus and functional changes of the foetal heart,affecting foetal circulation.The right ventricular diastolic functions in foetuses with isolated SUA and in normal foetuses in the third trimester were evaluated using the spectral Doppler of blood flow in the foetal ductus venosus(DV).AIM To evaluate the right ventricular diastolic functions in foetuses with isolated SUA and in normal foetuses in the third trimester.METHODS Colour Doppler was used to measure the spectrum of foetal DV and tricuspid orifice in 34 foetuses with isolated SUA aged 28-39 wk and in age-matched healthy controls.The DV flow velocities and velocity ratios were measured.The early passive/late active(E/A)ratio at the tricuspid orifice and tissue Doppler Tei index of the foetal right ventricular in the two groups were also measured.RESULTS During the third trimester,the isolated SUA group showed a lower‘a’-wave peak velocity in the DV than the control group(P<0.05).The correlations between the velocity ratios and E/A ratio at the tricuspid orifice in the two groups were analysed,and the correlation between the ventricular late diastolic velocity/ventricular diastolic peak flow velocity and E/A ratios was the best(R^2of the isolated SUA group:0.520;R2 of the control group:0.358).The correlations between the velocity ratios and tissue Doppler Tei index of foetal right ventricular in the two groups were analysed,and the correlation between the pulsatility index for veins(PIV)and tissue Doppler Tei index ratios was the best(R2 of the isolated SUA group:0.865;R2 of the control group:0.627).CONCLUSION In the isolated SUA group,the atrial systolic peak velocity‘a’decreased,and this finding might be related to the changes in foetal cardiac functions.The ratio of ventricular late diastolic velocity to ventricular diastolic peak flow velocity was closely related to the E/A ratio at the tricuspid valve and can be used to identify changes in the right ventricular diastolic functions of isolated SUA and healthy foetuses.PIV was closely related to the tissue Doppler Tei index of the foetal right ventricular and can be used to identify the right ventricular overall functions of isolated SUA and healthy foetuses.

Postnatal development of fetuses with a single umbilical artery:differences between malformed and non-malformed infants

Background:The presence of a single umbilical artery(SUA)is a fetal soft marker of congenital abnormalities.Among the most common related malformations,there are cardiological,nephrourological and digestive anomalies,most of which are considered to have a vascular etiology.There is an association between increased incidence of intrauterine growth retardation and adverse perinatal indicators,but whether this association is due to related anomalies or isolated SUA(SUA)is controvisal.Methods:We reviewed 96 cases of iSUA and non-isolated SUA(niSUA),diagnosed in a period of two years in a referral hospital for high-risk pregnancies.Data on prenatal explorations,including fetal ultrasonography and karyotyping,were obtained.niSUA was diagnosed when no malformations were found prenatally or in postnatal evaluation.Results:Sixty-six newborns(68.8%)had no other anomalies and 30(31.3%)presented with a variety of malformations including heart diseases,urophaties,digestive,nervous and musculoskeletal disorders,genetic abnormalities and complex malformations.Cardiological and nephrourological abnormalities were found to be the most frequent association with a SUA(both in 23.8%of malformed SUA newborns).Intrauterine growth restriction was not higher in iSUA newborns than in a normal population.Utrasound allowed optimal prenatal diagnosis in most cases.Conclusions:The prognosis of the fetus with a SUA is determined by the presence of other malformations observed by an expert sonographer.If no other findings are made,only a routine physical examination should be performed in newborns,but no other complementary examinations are required.