Semiquantitative classification of ductus venosus blood flow patterns.

OBJECTIVES: To identify the range of waveform abnormalities in the ductus venosus (DV) characterized by their timing in the cardiac cycle and to evaluate if they can be categorized into distinct patterns. METHODS: DV velocity ratios were calculated from peak velocities during ventricular systole (S), end-systolic ventricular relaxation (v), early diastole (D) and atrial systole (a) (S/v, S/D, v/D, S/a, v/a and D/a ratios). The ratios were converted to their Z-scores and elevation > 2 SD was assigned as abnormal. Combinations of ratio abnormalities were grouped to define distinct waveform patterns and their distribution was related to the clinical presentation. RESULTS: Five-hundred and forty-two abnormal DV waveforms fell into three principal patterns. In Pattern 1 only the a-wave-related ratios were abnormal (180, 33.2%), in Pattern 2 the v/D ratio was abnormal (143, 26.3%) and in Pattern 3 combinations of a-wave abnormalities in the presence of a normal v/D ratio were normal (94, 17.3%). CONCLUSIONS: Interpretation of venous waveform patterns is complex because the multiphasic waveforms reflect events in the cardiac cycle that may be differentially affected by clinical pathology. We sought to present a classification for the DV flow profile that characterizes abnormal flow confined to atrial systole and occurs during ventricular relaxation or during holodiastole. Further research is warranted to determine the significance of these patterns in specific fetal conditions.

Correlation analysis of ductus venosus velocity indices and fetal cardiac function.

OBJECTIVE: To examine the relationships between the ductus venosus (DV) pulsatility index for veins (PIV), individual DV velocity ratios and diastolic and global myocardial cardiac function. METHODS: Doppler measurements of the DV, atrioventricular (AV) valves and ventricular in- and outflow were analyzed. The DV-PIV and velocity ratios for individual phases (systole (S), end-systolic relaxation (v), early diastole (D), atrial systole (a), and S/v, S/D, S/a, v/D, v/a and D/a ratios) were calculated. The ratio of early and late diastolic peak velocities across AV valves was calculated (E/A ratio). Left modified myocardial performance index (MPI) was calculated from time intervals between valve clicks defining isovolumetric contraction/relaxation and ejection times. All values were transformed to Z-scores. The distributions of DV velocity ratios and DV-PIV were correlated with cardiac Doppler parameters. RESULTS: A total of 1163 examinations from 213 fetuses, most of which were at risk for cardiac dysfunction, were included in the study. In 742 the PIV was normal and in 421 PIV was elevated > 2 SD above the normal mean. The DV-PIV correlated with velocity ratios (P < 0.0001) but not with E/A ratios and the MPI. S/v and v/D ratios were related to tricuspid and mitral E/A ratios and left ventricular MPI. The S/D ratio was only related to both E/A ratios. There was no relationship between a-wave-related velocity ratios and cardiac function. CONCLUSIONS: Velocity ratios of the DV show relationships with cardiac function that are not reflected by the PIV alone. In cases of suspected fetal cardiac dysfunction based on elevated DV-PIV, analysis of velocity ratios or direct cardiac evaluation is suggested to determine the underlying pathophysiology.

Four cases of fetal intra-abdominal umbilical vein varix: a single centre's approach to management.

Fetal intra-abdominal umbilical vein (FIUV) varix is a rare prenatal abnormality characterised by a focal intrahepatic or extrahepatic dilatation of the intra-abdominal portion of the umbilical vein. Usually, it is an isolated finding, but in some cases it can be associated to other fetal anomalies. Thrombosis is a possible complication of FIUV varix and it can lead to poor fetal or neonatal outcome. We describe four consecutive cases of FIUV varix diagnosed in our Unit and managed with low-dose aspirin (LDA) prophylaxis until the 35th week of gestation. None of the fetuses developed thrombosis of the varix and the neonatal outcomes were good in all the cases.