Reference ranges for Doppler‐assessed pulmonary venous blood flow velocities and pulsatility indices in normal human fetuses

Giugni

Journal of Fetal Medicine

et al. 2015

Congenital heart disease (CHD) is the leading cause of infant mortality. Nevertheless, routine prenatal ultrasound only detects 30 %-50 % of CHD cases. Therefore, emphasis should be placed on early predictors of CHD that allow physicians to timely refer high-risk patient to specialized fetal echocardiography, in order to maximize chances of improved outcomes. The fetal venous system has been the focus of attention as a marker of heart function. Yet, there exist inconsistent data about the acquisition of pulmonary venous flow in early pregnancy. This study aims to determine the feasibility of fetal pulmonary venous flow acquisition in early pregnancy, and the association between pulmonary vein (A-wave) flow reversal and the presence of CHD. Total of 211 consecutive pregnant women, between 12 and 15 weeks of gestation, underwent routine obstetric ultrasound along with basic fetal echocardiography including fetal pulmonary venous flow assessment. The pulmonary venous flow velocity waveforms were acquired by either Doppler or Doppler plus enhance flow technique based on equipment availability. All the cases were re-evaluated by specialized fetal echocardiography during late pregnancy to identify congenital heart anomalies. The acquisition of fetal pulmonary vein, between 12 and 15 weeks of gestation, was successfully accomplished in 87.7 % of cases. Five out of seven fetuses with end-diastolic (A-wave) pulmonary venous flow reversal were associated with confirmed cardiac anomaly. In this pilot study, pulmonary venous (A-wave) flow reversal was associated with cardiac anomalies in 86.8 % of cases (p = 0.001). This pilot study proposes that Doppler interrogation of fetal pulmonary vein flow during early pregnancy is feasible. Furthermore, the presence of pulmonary vein (A-wave) reversal might represent a marker of major cardiac anomalies. Further investigation is needed to confirm these findings.

“…This mirrors the flow patterns described in late pregnancy by previous studies [7,10,11]. A pulmonary vein A-wave reversal was only described in 0.55 % of normal fetuses.…”

Section: Detection Of Fetal Pulmonary Venous Flow Waveforms During Easupporting

confidence: 67%

Section: Detection Of Fetal Pulmonary Venous Flow Waveforms During Eamentioning

confidence: 78%

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Evaluation of Fetal Pulmonary Veins During Early Gestation by Pulsed Doppler Ultrasound: A Feasibility Study

Giugni

Journal of Fetal Medicine

et al. 2015

“…Doppler recordings were obtained with the angle of insonation as parallel to the direction of flow as possible, with the sample volume placed in the pulmonary vein immediately proximal to its entry into the left atrium, as previously described. 13,15,18 Low-pass filters were adjusted to ensure recording of lower-velocity signals.…”

Section: Pulmonary Venous Flow Analysismentioning

confidence: 99%

Predictive Value of Fetal Pulmonary Venous Flow Patterns in Identifying the Need for Atrial Septoplasty in the Newborn With Hypoplastic Left Ventricle

et al. 2005

Background-Pulmonary venous Doppler (PVD) flow patterns in the fetus with hypoplastic left heart syndrome (HLHS) have been correlated with restrictive interatrial communication or intact atrial septum (RAS) postnatally; however, the ability of PVD to identify the neonate requiring emergent atrial septoplasty (EAS) for severe left atrial hypertension and hypoxemia has not been critically evaluated. It was the purpose of this study to determine the predictive power of fetal PVD in identifying the need for EAS in newborns with HLHS and RAS. Methods and Results-Forty-one patients with fetal PVD flow analysis and postnatally confirmed HLHS were studied.Pulsed-wave assessment of PVD flow included S-, D-, and A-wave velocity, time-velocity integral (VTI) of forward and reverse flow, and S/D velocity and forward/reverse VTI ratio. Neonatal EAS was used as the primary clinical outcome variable. Receiver operating characteristic curves were used to determine cutpoints at which PVD indices best predicted EAS. Cutpoints were evaluated for clinical accuracy and usefulness by use of Bayesian analysis. Eight of 41 subjects underwent EAS. Need for EAS was most accurately predicted by forward/reverse VTI ratio Ͻ5 (sensitivity, 0.88, 95% CI, 0.49 to 0.99; specificity, 0.97, 95% CI, 0.82 to 0.99), which, when present, increases the posttest likelihood of EAS to 74%, assuming a pretest prevalence of 10%. Accuracy and usefulness of other PVD indices were affected by false-positive results. Conclusions-In the fetus with HLHS, a PVD forward/reverse VTI ratio of Ͻ5 is the strongest predictor of the need for EAS in the newborn period. These observations should improve our ability to identify and expectantly manage the fetus with HLHS and RAS.

“…1,2 The pulmonary vein pulsatility index (PVPI) reflects the relative impedance to the forward flow and is believed to be better comparable than absolute values of individual waveforms and independent of the insonation angle. 3 The standard position of the Doppler sample volume to obtain the pulmonary vein flow is in the distal portion of the vein, adjacent to the venoatrial junction, where the vessel diameter is maximal. Morphometric studies of the pulmonary venous vasculature confirm that the pulmonary veins show a tapering pattern from the left atrium to the hylum, 4,5 and mathematical models show that the flow wave is altered by the change in the cross-sectional area of the vessel.…”

mentioning

confidence: 99%

Dynamics of the Pulmonary Venous Flow in the Fetus and Its Association With Vascular Diameter

Zielinsky¹,

Piccoli²,

Gus³

et al. 2003

Circulation

Background-The usual positioning of the Doppler sample volume to assess fetal pulmonary vein flow is in the distal portion of the vein, where the vessel diameter is maximal. This study was performed to test the association of the pulmonary vein pulsatility index (PVPI) with the vessel diameter. Methods and Results-Twenty-three normal fetuses (mean gestational age, 28.6Ϯ5.3 weeks) were studied by Doppler echocardiography. Pulmonary right upper vein flow was assessed adjacent to the venoatrial junction ("distal" position) and in the middle of the vein ("proximal" position). The vessel diameter was measured by 2D echocardiography with power Doppler, and the PVPI was obtained by the ratio (maximal velocity [systolic or diastolic peak]Ϫminimal velocity [presystolic peak])/mean velocity. The statistical analysis used t test and exponential correlation studies. Mean distal diameter was 0.33Ϯ0.10 cm (0.11 to 0.57 cm), and mean proximal diameter was 0.16Ϯ0.08 cm (0.11 to 0.25 cm) (PϽ0.0001). Mean distal PVPI was 0.84Ϯ0.21 (0.59 to 1.38), and mean proximal PVPI was 2.09Ϯ0.59 (1.23 to 3.11) (PϽ0.0001). Exponential inverse correlation between pulmonary vein diameter and pulsatility index was highly significant (PϽ0.0001), with a determination coefficient of 0.439. Conclusions-In the normal fetus, the pulmonary venous flow pulsatility decreases from the lung to the heart, and this parameter is inversely correlated to the diameter of the pulmonary vein, which increases from its proximal to its distal portion. This study emphasizes the importance of the correct positioning of the Doppler sample volume, adjacent to the venoatrial junction, to assess pulmonary venous flow dynamics.