Middle cerebral artery peak systolic velocity: a new Doppler parameter in the assessment of growth-restricted fetus G.MARI, F HANIF, M KRUGER, et. al,. Ultrasound Obstet Gynecol 2007;29:310-6

Introduction IUGR secondary to placental insufficiency, redistribute blood flow from the periphery to the brain Doppler of umbilical artery(UA) PI is increased and middle cerebral artery(MCA) PI is decreased in fetuses at risk for perinatal morbidity and mortality MCA peak systolic velocity(PSV) increased in IUGR fetuses, suggesting as good predictor of perinatal mortality (Ozcan T;1998)

Purpose To determine the relationship between MCA-PSV and perinatal mortality in preterm IUGR fetuses with abnormal UA-PI. To compare the performance of MCA-PI, MCA-PSV, and UA absent or reversed end-diastolic flow velocity(ARED) in the prediction of perinatal mortality To determine longitudinal changes that MCA-PI and MCA-PSV in IUGR fetuses To test the hypothesis, the MCA-PSV can provide additional information on the prognosis of hypoxemic IUGR fetuses

Material and methods IUGR fetuses(30 cases) Singleton An estimated weight <3rd percentile UA-PI >95th CI Normal anatomy MCA doppler with angle close to 0˚ within 8 days before delivery or fetal demise All were delivered at <33 weeks’ gestation

Prospective longitudinal study 10 cases in which the MCA-PI and MCA-PSV were recorded longitudinally from the time of diagnosis until delivery The number of measurement ranged from 3 to 8 (median5) GA at entrance into the study ranged from 20+6 to 26+4 weeks, and GA at delivery between 23+1 and 28+6 weeks Fetus was <500 g in weight, offered the option of non-intervention Mortality occurring between 20 weeks’ gestation and 28 days after birth Major neonatal complications as IVH grade III or IV or bronchopulmonary dysplasia (BPD)

increased increased decreased no change decreased decreased increased

Results MCA-PSV predicted the perinatal mortality; odds ratio,14; 95% CI, 1.4-130; p<0.05) In death infants, lower GA at delivery 25+6 weeks vs. 29+0 weeks; p=0.001) No survivors at <25+0 weeks; 2 IUFD, 3 neonatal death. Between 25 and 29 weeks; 4 IUFD, 2 neonatal death. At >29 weeks, all the fetuses survived (n=10)

BPD was significantly related to an abnormal MCA-PSV (odds ratio, 12; 95% CI, 1.1-139; p=0.037) MCA-PI (odds ratio, 0.6; 95% CI, 0.4-1.1; p=0.058) UA-ARED (odds ratio, 30; 95% CI, 2.2-405; p=0.006) Lower GW at delivery in infants who developed BPD(27+6 vs. 30+3 weeks; p<0.05) Among survived infants, none developed IVH grade III or IV

Prospective longitudinal study Abnormal MCA-PI preceded the appearance of an abnormal MCA-PSV. The MCA-PSV showed an initial increase in velocity and it decreased before fetal demise or the appearance of non-reassuring testing(7) and high velocity(3). The MCA-PI did not have a consistent pattern; progressive decreased(3), increased(6) and unchanged(1).

Discussion MCA-PI & UA-PI for the assessment of fetuses with IUGR MCA-PSV complementation provide more clearer information than dose MCA-PI Abnormal MCA-PI but normal MCA-PSV, IUGR condition is less severe MCA-PI increased and MCA-PSV decreased, the fetus start to decompensate (before fetal demise occurred)

UA-ARED(+) normal MCA-PSV, most infant survived and abnormal MCA-PSV, most of infant that died predicted the perinatal mortality better than UA-ARED Between 25 and 29 weeks, abnormal MCA-PI in 12/15 fetuses, none of fetuses died when MCA-PSV was normal MCA-PSV is a better predictor of perinatal mortality than is MCA-PI

In IUGR fetus, low MCA-PI reflect decreased brain vascular resistance and increased in blood flow. MCA-PSV reflects increased blood flow to the brain through an elevated left cardiac output and increased placental vascular resistance. More severe, a portion of the blood ejected from right ventricle is shifted to the brain through the aortic isthmus because of a high vascular resistance in the descending aorta.

Further study MCA-PSV as reliable predictor of severe fetal anemia (Mari;2000); secondary to raised cardiac output and decreased blood viscosity Betamethasone for lung maturity can affect blood viscosity Blood pressure plays a role in theses cerebral blood changes Heterogeneous IUGR group ; secondary to placental insufficiency, idiopathic IUGR etc. Assessing the correlation of MCA-PSV with other vessels such as aortic isthmus, ductus venous.