title: Differential effects of intravenous hydralazine on myoendometrial and placental blood flow in hypertensive pregnant ewes.
abstract: OBJECTIVE
  The differential vasoactive effects of hydralazine on the uteroplacental vascular bed were studied.
  
  
  METHODS
  After control measurements were taken, near-term chronically prepared pregnant sheep were continuously infused with angiotensin II. Maternal arterial pressure was increased by 32 mm Hg. Hydralazine was then administered; the effects on regional resistance and blood flow were evaluated with a radionuclide-labeled microsphere technique. Analysis of variance for repeated measures was used to compare observations.
  
  
  RESULTS
  When compared with the hypertensive state, hydralazine caused the following changes by 40 minutes (mean +/- SEM): Although maternal blood pressure fell 31% +/- 5% (p = 0.0005), placental blood flow was unchanged, total uteroplacental blood flow increased 24% +/- 8% (p = 0.03), total uteroplacental resistance decreased 43% +/- 4% (p = 0.0002), placental resistance decreased 19% +/- 9% (p = 0.01), myoendometrial blood flow increased 390% +/- 82% (p = 0.0005), and myoendometrial resistance decreased 82% +/- 4% (p = 0.0005).
  
  
  CONCLUSIONS
  In angiotensin II-induced hypertensive ewes, hydralazine is an effective dilator of the uteroplacental vascular bed and can maintain placental blood flow while blood pressure.
authors: Department of Obstetrics and Gynecology, University of Wisconsin-Madison.
authors: S L
authors: SL
authors: Pedron
authors: D L
authors: DL
authors: Reid
authors: J M
authors: JM
authors: Barnard
authors: J B
authors: JB
authors: Henry
authors: T M
authors: TM
authors: Phernetton
authors: J H
authors: JH
authors: Rankin
mesh_terms: D000311:Adrenal Glands / Q000098:blood supply; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D004717:Endometrium / Q000098:blood supply*; D005260:Female; D006830:Hydralazine / Q000494:pharmacology*; D006973:Hypertension / Q000503:physiopathology*; D007275:Injections, Intravenous; D008863:Microspheres; D009215:Myometrium / Q000098:blood supply*; D010920:Placenta / Q000098:blood supply; D011247:Pregnancy; D012039:Regional Blood Flow / Q000187:drug effects; D012079:Renal Circulation / Q000187:drug effects; D012756:Sheep; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D000804:Angiotensin II; D006830:Hydralazine