Cerebroplacental ratio as predictor of adverse perinatal outcome in the third trimester.

INTRODUCTION: Fetal growth restriction is associated with adverse perinatal outcome and the clinical management of these pregnancies is a challenge. The aim of this study was to investigate the potential of cerebroplacental ratio (CPR) to predict adverse perinatal outcome in high-risk pregnancies in the third trimester. Another aim was to study whether the CPR has better predictive value than its components, middle cerebral artery (MCA) pulsatility index (PI) and umbilical artery (UA) PI. MATERIAL AND METHODS: The study was a retrospective cohort study including 1573 singleton high-risk pregnancies with Doppler examinations performed at 32+0 to 40+6 gestational weeks at Lund University Hospital and the University Hospital of Malmö between 29 December 1994 and 31 December 2017. Receiver operating characteristics (ROC) curves were used to investigate the predictive value of the gestational age-specific z-scores for CPR, UA PI and MCA PI, respectively, for the primary outcome "perinatal asphyxia/mortality" and the secondary outcomes "birthweight small for gestational age (SGA)" and two composite outcomes: "appropriate for gestational age/large for gestational age liveborn infants with neonatal morbidity" and "SGA liveborn infants with neonatal morbidity." RESULTS: The performance in predicting perinatal asphyxia/mortality was poor for all three variables and did not differ significantly. The ROC area under curve (AUC) was 0.56, 0.55 and 0.53 for CPR, UA PI and MCA PI z-scores, respectively. The ROC AUC for CPR z-scores to predict SGA was 0.73, significantly higher than that for either UA PI or MCA PI (P < .001). The ability of CPR and the MCA PI to predict appropriate for gestational age/large for gestational age infant morbidity and SGA infant morbidity was similar and significantly better than UA PI (P < .001). CONCLUSIONS: In the present study, none of the three Doppler measures proved to be useful in predicting perinatal asphyxia and mortality. CPR and MCA PI were equally good in predicting neonatal morbidity, especially in SGA pregnancies, and both were significantly better predictors than the UA PI. CPR had a high predictive value for SGA at birth, better than that of its two components, UA PI and MCA PI.

Doppler Audio Signal Analysis as an Additional Tool in Evaluation of Umbilical Artery Circulation.

Purpose To investigate the predictive capacity of a new method for sound spectrum analysis of Doppler signals recorded from the umbilical artery in high-risk pregnancies. Material and Methods The retrospective study comprised 127 pregnant women with various pregnancy complications between 23 and 39 gestational weeks. Umbilical artery blood flow velocity waveforms were recorded with Doppler ultrasound and characterized by pulsatility index (PI) and blood flow class (BFC). Doppler audio signals were stored on a digital video recorder and the sound frequency at the energy level 15 dB below its peak (MAXpeak-15 dB) was estimated off-line. The prediction of probability for composite adverse pregnancy outcome (operative delivery for fetal distress, admission to neonatal intensive care unit, perinatal death) was evaluated using the area under the curve (AUC) of the receiver operating characteristics (ROC) curve. Results With increasing umbilical artery BFC, the MAXpeak-15 dB frequencies decreased (p < 0.0001) and the PI increased (p < 0.0001). The ROC AUCs for adverse outcome for MAXpeak-15 dB and for PI were 0.842 and 0.836 (p = 0.88), respectively. For the combination of MAXpeak-15 dB and PI, the corresponding AUC was 0.894, significantly higher than that of PI (p < 0.03) and of MAXpeak-15 dB (p < 0.05). Conclusion Umbilical artery Doppler sound spectrum analysis might be a useful supplement to PI in the clinical evaluation of fetoplacental circulation.

Audio spectrum analysis of umbilical artery Doppler ultrasound signals applied to a clinical material.

Analysis of umbilical artery flow velocity waveforms characterized by pulsatility index (PI) is used to evaluate fetoplacental circulation in high-risk pregnancies. However, an experienced sonographer may be able to further differentiate between various timbres of Doppler audio signals. Recently, we have developed a method for objective audio signal characterization; the method has been tested in an animal model. In the present pilot study, the method was for the first time applied to human pregnancies. Doppler umbilical artery velocimetry was performed in 13 preterm fetuses before and after two doses of 12 mg betamethasone. The auditory measure defined by the frequency band where the spectral energy had dropped 15 dB from its maximum level (MAXpeak-15 dB ), increased two days after betamethasone administration (p = 0.001) parallel with a less pronounced decrease in PI (p = 0.04). The new auditory parameter MAXpeak-15 dB reflected the changes more sensitively than the PI did.

Operator auditory perception and spectral quantification of umbilical artery Doppler ultrasound signals.

OBJECTIVE: An experienced sonographer can by listening to the Doppler audio signals perceive various timbres that distinguish different types of umbilical artery flow despite an unchanged pulsatility index (PI). Our aim was to develop an objective measure of the Doppler audio signals recorded from fetoplacental circulation in a sheep model. METHODS: Various degrees of pathological flow velocity waveforms in the umbilical artery, similar to those in human complicated pregnancies, were induced by microsphere embolization of the placental bed (embolization model, 7 lamb fetuses, 370 Doppler recordings) or by fetal hemodilution (anemia model, 4 lamb fetuses, 184 recordings). A subjective 11-step operator auditory scale (OAS) was related to conventional Doppler parameters, PI and time average mean velocity (TAM), and to sound frequency analysis of Doppler signals (sound frequency with the maximum energy content [MAXpeak] and frequency band at maximum level minus 15 dB [MAXpeak-15 dB] over several heart cycles). RESULTS: WE FOUND A NEGATIVE CORRELATION BETWEEN THE OAS AND PI: median Rho -0.73 (range -0.35- -0.94) and -0.68 (range -0.57- -0.78) in the two lamb models, respectively. There was a positive correlation between OAS and TAM in both models: median Rho 0.80 (range 0.58-0.95) and 0.90 (range 0.78-0.95), respectively. A strong correlation was found between TAM and the results of sound spectrum analysis; in the embolization model the median r was 0.91 (range 0.88-0.97) for MAXpeak and 0.91 (range 0.82-0.98) for MAXpeak-15 dB. In the anemia model, the corresponding values were 0.92 (range 0.78-0.96) and 0.96 (range 0.89-0.98), respectively. CONCLUSION: Audio-spectrum analysis reflects the subjective perception of Doppler sound signals in the umbilical artery and has a strong correlation to TAM-velocity. This information might be of importance for clinical management of complicated pregnancies as an addition to conventional Doppler parameters.

Coronary flow in neonates with impaired intrauterine growth.

BACKGROUND: Subclinical myocardial injury has been reported in newborns with fetal weights < 2 SDs for gestational age. Intrauterine growth restriction might affect cardiac function and coronary flow (CF). METHODS: Seventeen newborns with intrauterine growth restriction and 15 age-matched healthy controls were enrolled in the study. Blood flow in the umbilical artery and maternal uterine artery was assessed using Doppler velocimetry. Cardiac function and left anterior descending coronary artery CF were measured using transthoracic Doppler echocardiography at 1 week of age. RESULTS: The mean growth deviation of the newborns from normal was -2.5 ± 0.2 SDs. Percentage left ventricular shortening fraction was 39 ± 4.3% in patients and 42 ± 4.1% in controls (P = .40), and the mean left ventricular mass index was 86.6 g/m(2) in patients and 73.7 g/m(2) in controls (P < .01). The mean left anterior descending coronary artery diameter was 0.99 ± 0.1 mm in patients and 0.8 ± 0.1 mm in controls (P = .002). The left anterior descending coronary artery flow velocity-time integral was correlated with left ventricular mass index (r = 0.31, P = .007) and with mitral peak E/A ratio (r = 0.74, P = .01). Intrauterine growth restriction was associated with increased peak flow velocity in diastole (34.5 ± 4 vs 19 ± 6 cm/sec in controls, P = .0001), as well as increased CF (37 ± 7.3 vs 8.2 ± 3.0 mL/min in controls, P = .001). CONCLUSIONS: CF is significantly increased in neonates with impaired intrauterine growth. Left ventricular mass index is increased, but systolic and diastolic function remains normal. The clinical significance of increased CF is unclear, but it might lead to decreased CF reserve.

Placental ischemia and changes in umbilical and uteroplacental arterial and venous hemodynamics.

OBJECTIVE: To relate Doppler velocimetry findings in fetoplacental and uteroplacental circulation to placental histomorphology. MATERIAL AND METHODS: In 14 uncomplicated and 31 high-risk pregnancies Doppler velocimetry was performed in umbilical artery and vein, and in maternal uterine veins and arteries during the second half of gestation. Histopathology of the placentas was examined, especially for signs of ischemia and inflammation. RESULTS: All fetuses in uncomplicated pregnancies had normal flow velocity waveforms in umbilical artery; in the high-risk group, 18 fetuses had abnormal flow (increased PI or absent/reverse end-diastolic flow). The latter group had more often high ischemic score and infarctions in the placenta than found in pregnancies with normal umbilical artery flow (p < 0.001 and p = 0.02, respectively). Similarly, the abnormal uterine artery flow pattern (uterine artery score 3-4) occurred more often with high ischemic score and placenta infarctions (p < 0.001 and p < 0.001, respectively). No significant associations were found between the uterine venous flow type and placental ischemia. CONCLUSION: Placental ischemic morphological changes were associated with Doppler ultrasound signs of increased resistance to arterial blood flow, both on the fetal and maternal sides of the placenta. No significant relation to the uterine venous flow velocities was found.