Giuseppe Rizzo

NORMAL VALUES OF PULSATILITY INDEX FROM FETAL VESSELS: A CROSS-SECTIONAL STUDY ON 1556 HEALTHY FETUSES

In a cross-sectional study of 1556 uncomplicated pregnancies velocity waveforms were recorded at the level of fetal umbilical artery, descending aorta, renal artery, internal carotid artery and middle cerebral artery. Reference limits for the Pulsatility Index of each vessel were constructed by regression analysis and a progressive fall during gestation was evidenced in all the vascular districts investigated with the exception of descending aorta. Furthermore we calculated the ratios between Pulsatility Index values of cerebral and peripheral vessels which may be relevant for the early diagnosis of the haemodynamic abnormalities occurring during the brain sparing effect.

Fetal cardiac function in intrauterine growth retardation.

Blood-flow velocity waveforms are altered in several peripheral vascular beds of fetuses whose intrauterine growth is retarded because of placental insufficiency. We investigated these concomitant changes in cardiac function. Color and pulsed Doppler echocardiographic recordings were performed in 124 fetuses with intrauterine growth retardation. These fetuses were free of structural and chromosomal abnormalities and were characterized by increased umbilical artery resistance and reduced middle cerebral artery resistance. Twenty-four of these fetuses were also studied at weekly intervals until the onset of antepartum late heart rate decelerations. Blood-flow velocity waveforms were obtained from the aortic and pulmonary valves, and the following variables were measured: peak systolic velocity, time to peak velocity, the product of time velocity integral multiplied by heart rate, left and right cardiac output, and the right/left ratios of the product of time velocity integrals multiplied by heart rate and cardiac output. When compared with previously established norms, both aortic and pulmonary peak systolic velocities and pulmonary time to peak velocity were reduced; aortic time to peak velocity increased. Left cardiac output and the product of the aortic time velocity integral multiplied by the heart rate increased and right cardiac output and the product of the pulmonary time velocity integral multiplied by the heart rate decreased, resulting in reduced right/left ratios. In the 24 fetuses studied longitudinally, time to peak velocities and the right/left flow ratios remained stable. However, aortic and pulmonary peak velocities and cardiac output declined significantly in contrast to an expected rise with advancing gestation. The fall in cardiac output and aortic and pulmonary peak velocities was directly related to umbilical artery pH at birth. This study provides evidence of a modified cardiac function that seems to deteriorate progressively with the advancing gestation of fetuses with intrauterine growth retardation.

The value of fetal fibronectin in cervical and vaginal secretions and of ultrasonographic examination of the uterine cervix in predicting premature delivery for patients with preterm labor and intact membranes.

OBJECTIVE We compared the diagnostic performances of fetal fibronectin assay of cervical and vaginal secretions and of transvaginal ultrasonographic evaluation of the uterine cervix in the prediction of preterm delivery of patients presenting with preterm labor and intact membranes. STUDY DESIGN One hundred eight patients admitted to the hospital for preterm labor and with intact membranes underwent assay of fibronectin in the cervical and vaginal secretions and transvaginal ultrasonographic evaluation of the uterine cervix. The ultrasonographic parameters evaluated were cervical length, presence of funneling, and cervical index ([Funnel length + 1]/Cervical length). Outcome measures were occurrence of preterm delivery, defined as birth before the thirty-seventh week of gestation, and the admission-to-delivery interval. RESULTS Forty-seven patients (43.5%) were delivered preterm. Receiver characteristic curve analysis showed that a level of fetal fibronectin in cervical secretions > or = 60 ng/ml had the highest diagnostic performance in predicting preterm delivery (sensitivity 80.9%, specificity 83.6%). Multiple stepwise logistic regression analysis indicated that the cervical index significantly improved the prediction of preterm delivery achieved by the fetal fibronectin assay. In patients with cervical secretion fibronectin levels > or = 60 ng/ml, survival analysis showed a shorter admission-to-delivery interval in the presence of an abnormal cervical index (p < or = 0.001). CONCLUSIONS The assay of fetal fibronectin in cervical secretions is more accurate than ultrasonographic evaluation of the uterine cervix in the prediction of preterm delivery. Combined use of the fetal fibronectin assay and the cervical index improves the diagnostic efficiency and allows prediction of the admission-to-delivery interval, identifying a subgroup of patients who may require aggressive treatment.

Interleukin-6 concentrations in cervical secretions identify microbial invasion of the amniotic cavity in patients with preterm labor and intact membranes

OBJECTIVE The objectives of this study were to determine whether cytokine levels in cervical secretions were increased in the presence of microbial invasion of the amniotic cavity in patients with preterm labor and intact membranes and to relate concentrations to cytokine levels in amniotic fluid, cervicovaginal microflora, and the presence of chorioamnionitis. STUDY DESIGN Cervical secretions were sampled immediately before amniocentesis in 92 patients admitted for preterm labor with singleton pregnancies and intact membranes. Amniotic fluid was cultured and the following cytokines were measured in amniotic fluid and cervical secretions: interleukin-1 beta, interleukin-1 receptor antagonist, tumor necrosis factor-alpha, and interleukin-6. The cervicovaginal microflora and placentas (n = 42) were also analyzed. RESULTS A total of 19.56% (18/92) of the amniotic fluid cultures had positive results. All the cytokines tested showed significantly higher levels in cervical secretions in the presence of intraamniotic infection. There were significant relationships between the concentrations of interleukin-6 and interleukin-1 receptor antagonist in amniotic fluid and cervical secretions. A concentration of interleukin-6 in cervical secretions > 410 pg/ml had a sensitivity of 66.8% and a specificity of 90.5% and a relative risk of 7.7 for intraamniotic infection, higher than the other cytokines tested. There were no relationships between the presence of bacterial vaginosis and cervicovaginal pathogens and cervical cytokine levels. In the presence of chorioamnionitis, cervical concentrations of interleukin-6 and interleukin-1 receptor antagonist were significantly increased in spite of negative amniotic fluid culture results. CONCLUSION The measurement of interleukin-6 in cervical secretions may help to noninvasively identify intraamniotic infection among pregnancies with preterm labor and intact membranes.

The development of abnormal heart rate patterns after absent end-diastolic velocity in umbilical artery : analysis of risk factors

OBJECTIVES Our objectives were to evaluate the time interval elapsing between the occurrence of absent end-diastolic velocity in the umbilical artery and either the development abnormal fetal heart rate patterns or delivery and to establish the maternal and fetal factors that may affect this interval. STUDY DESIGN Thirty-seven fetuses free of structural and chromosomal abnormalities in which the development of absent end-diastolic velocity in umbilical artery was evidenced by serial Doppler recordings were studied. At the first occurrence the following factors were considered: gestational age, presence of hypertension or preeclampsia, amniotic fluid index, severity of growth retardation, and 10 different Doppler indices calculated from extracardiac and intracardiac vascular districts. Actuarial statistical methods were applied, with the occurrence of antepartum late heart rate deceleration as the censoring variable. RESULTS The interval between the first occurrence of absent end-diastolic velocity in umbilical artery and delivery ranged from 1 to 26 days. Indications for delivery were the development of antepartum late heart rate decelerations in 23 fetuses (62.1%) and different maternal or fetal complications in the remaining 14 fetuses. Multivariate analysis revealed that gestational age and the presence of hypertension and pulsations in umbilical vein were the dominant factors in determining the length of this time interval. CONCLUSION The duration of the time interval between the occurrence of absent end-diastolic velocity in umbilical artery and abnormal heart rate pattern differs considerably among fetuses, and it is mainly determined by gestational age and presence of maternal hypertension and pulsations in umbilical vein.

Inferior vena cava flow velocity waveforms in appropriate- and small-for-gestational-age fetuses.

Reference ranges of inferior vena cava flow velocities were constructed from a cross-sectional study of 118 appropriate-for-gestational-age fetuses of 18 to 40 weeks of gestation. Blood flow velocity waveforms were recorded with color and pulsed Doppler equipment. Peak velocities and time velocity integrals were measured from inferior vena cava during systole, early diastole, and atrial contraction. The systolic-to-diastolic ratios between the peak velocities and time velocity integrals were calculated, and the reverse flow with atrial contraction was quantified as the percentage of forward flow (percentage of reverse flow). Recordings were also obtained from 79 small-for-gestational-age fetuses free of structural and chromosomal abnormalities, divided into three groups according to umbilical artery velocity waveforms: normal pulsatility index values (group 1, n = 26), pulsatility index greater than 95th percentile of our reference limits but presence of end-diastolic velocities (group 2, n = 33), and absence of end-diastolic velocities (group 3, n = 20). Fourteen fetuses of groups 2 and 3 were also studied at weekly intervals until the onset of antepartum late heart rate decelerations. In appropriate-for-gestational-age fetuses no changes were evident in peak velocities and time velocity integrals ratios, whereas the percentage of reverse flow significantly decreased with gestation. No significant differences were found between these values and those obtained in small-for-gestational-age fetuses of group 1. A significant increase of peak velocities and time velocity integrals ratios and of percentage of reverse flow was evidenced in fetuses of both group 2 and 3. The fetuses of groups 2 and 3 with a percentage of reverse flow above the 95% confidence interval showed a poorer perinatal outcome when compared with the fetuses of the same groups but with values inside the normal range. In the 14 fetuses longitudinally followed up until the onset of late heart rate decelerations a significant and progressive increase of peak velocities and time velocity integrals ratios and percentage of reverse flow was evidenced in spite of minimal changes in the pulsatility index from both umbilical artery and different peripheral fetal vessels. This study presents evidence that in small-for-gestational-age fetuses with abnormal Doppler-measured placental resistance the modified flow velocity patterns in the inferior vena cava seem to deteriorate progressively with advancing gestation.

Introducing array comparative genomic hybridization into routine prenatal diagnosis practice: a prospective study on over 1000 consecutive clinical cases

To assess the feasibility of offering array‐based comparative genomic hybridization testing for prenatal diagnosis as a first‐line test, a prospective study was performed, comparing the results achieved from array comparative genomic hybridization (aCGH) with those obtained from conventional karyotype.

The value of fetal arterial, cardiac and venous flows in predicting pH and blood gases measured in umbilical blood at cordocentesis in growth retarded fetuses

Objective To assess the value of Doppler indices, calculated from fetal arterial peripheral vessels, cardiac outflow tracts and venous vessels, in the identification of acidaemia, hypercapnia and hypoxaemia as determined by pH and gas analysis of fetal blood obtained by cordocentesis in growth retarded fetuses.

Umbilical vein pulsations: A physiologic finding in early gestation

OBJECTIVES The purpose of this study was to establish the incidence of umbilical vein pulsations in normal early pregnancies and to evaluate whether these pulsations are related to Doppler-measured vascular resistances in umbilical artery or central venous flow patterns. STUDY DESIGN We performed a cross-sectional study on 257 uneventful pregnancies at 7 to 16 weeks of gestation by means of transvaginal color and pulsed Doppler ultrasonography. Blood flow velocity waveforms were recorded from the umbilical artery, umbilical vein and, in 48 cases, also from fetal inferior vena cava. RESULTS Pulsations in the umbilical vein were evidenced in all cases until 8 weeks. From this gestational age on pulsations progressively disappeared, becoming completely absent at greater than or equal to 13 weeks. The incidence of pulsations in the umbilical vein was unrelated to umbilical artery pulsatility index values, the incidence of absent end-diastolic flow in umbilical artery, and fetal heart rate. In the inferior vena cava, reverse flow during atrial contraction was significantly higher (p less than or equal to 0.002) in cases with umbilical vein pulsations than in those cases without pulsations at a similar gestational age. CONCLUSIONS Pulsations in the umbilical vein are physiologically present during the first trimester of pregnancy and seem to be related to inferior vena cava flow patterns.

Ductus venosus velocity waveforms in appropriate and small for gestational age fetuses

The objective of this study was to evaluate differences in ductus venosus velocity waveforms between appropriate and small for gestational age fetuses by using a new index based on the ratio between systolic and atrial peak velocities. Ductus venosus velocity waveforms were cross-sectionally recorded in 164 appropriate for gestational age fetuses at 16-42 weeks of gestation and in 97 small for gestational age fetuses free from structural and chromosomal abnormalities between 24-36 weeks of gestation. Small for gestational age fetuses were divided according to the Doppler findings in arterial peripheral vessels: group A (n = 33), normal ratio between umbilical artery and middle cerebral artery Pulsatility Indices; group B (n = 41), umbilical artery/middle cerebral artery ratio > 95th centile but presence of end diastolic flow in umbilical artery; group C (n = 23), umbilical artery/middle cerebral artery ratio > 95th centile and absence of end diastolic flow in umbilical artery. Eighteen small for gestational age fetuses (10 from group B and 8 from group C) were also serially studied until delivery due to fetal distress. Ductus venosus velocity waveforms were recorded at the level of its origin from umbilical vein and the ratio between systolic and atrial peak velocities (systolic/atrial ratio) calculated. In appropriate for gestational age fetuses, systolic/atrial ratio values significantly decrease with gestation. No significant differences were found in systolic/atrial ratio between appropriate for gestational age fetuses and group A small for gestational age fetuses while, after correction for gestational age, significantly higher values were found in group B (P < or = 0.01) and group C (P < or = 0.001) fetuses. Among these fetuses, those with systolic/atrial ratio above the 95th confidence interval showed a poorer perinatal outcome. No relationships were found between systolic/atrial ratio and Pulsatility Index values from fetal arterial peripheral vessels, while a positive relationship was found with the percentage reverse flow in inferior vena cava. In fetuses serially followed, the systolic/atrial ratio progressively increased approaching the onset of abnormal fetal heart rate patterns. The systolic/atrial ratio allows the evaluation of ductus venosus hemodynamics in small for gestational age fetuses and this index may be useful in the monitoring of such fetuses.