title: Semiquantitative classification of ductus venosus blood flow patterns.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland, Baltimore, MD, USA.
authors.forename: O M
authors.initials: OM
authors.lastname: Turan
authors.forename: S
authors.initials: S
authors.lastname: Turan
authors.forename: L
authors.initials: L
authors.lastname: Sanapo
authors.forename: J I
authors.initials: JI
authors.lastname: Rosenbloom
authors.forename: A A
authors.initials: AA
authors.lastname: Baschat
mesh_terms: D001783:Blood Flow Velocity; D003971:Diastole; D005260:Female; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging*; D005318:Fetal Heart / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005330:Fetofetal Transfusion / Q000000981:diagnostic imaging*; D005333:Fetus / Q000098:blood supply*; D005865:Gestational Age; D006801:Humans; D008297:Male; D011247:Pregnancy; D012016:Reference Values; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013599:Systole; D018608:Ultrasonography, Doppler
keywords: atrial systole; cardiac cycle; velocity ratio; ventricular relaxation; waveform