title: Cerebrovascular hemodynamics in chronic hypertensive pregnant women who later develop superimposed preeclampsia.
abstract: OBJECTIVE
  We have previously shown that normotensive pregnant women who later develop preeclampsia demonstrate lower baseline pulsatility index (PI) and resistance index (RI) but normal vasodilatory responses to stimulation tests. In the current study, we tested the hypothesis that women with chronic hypertension who later developed superimposed preeclampsia behave similarly.
  
  
  METHODS
  Transcranial Doppler ultrasound was performed on 17 women with chronic hypertension during the second trimester of pregnancy to measure middle cerebral artery (MCA) velocities. Superimposed preeclampsia developed in seven patients (SUPER group) while the rest did not develop preeclampsia (CHT group). Measurements were performed in the left lateral position at baseline on room air, during 5% CO2 inhalation, and during a 2-minute isometric handgrip test. Blood pressure, heart rate, O2 saturation, and end-tidal PCO2 were recorded with each Doppler measurement. Mean PI, RI, and cerebral perfusion pressure (CPP) at each time were compared using two-way repeated measures analysis of variance. Statistical significance was set at P < .05.
  
  
  RESULTS
  The women who developed superimposed preeclampsia did this an average of 8.7 +/- 1.3 weeks after the study. MCA PI and RI were lower, and CPP higher, in the SUPER group compared to the CHT group (0.64, 0.46, and 80.7 vs 0.74, 0.51, and 63.6, respectively; P < .05). Both maneuvers caused reduction in MCA PI and RI in both groups, whereas CPP increased only in the SUPER group.
  
  
  CONCLUSIONS
  These findings suggest that women destined to develop preeclampsia have cerebral hemodynamic changes that predate the development of overt preeclampsia.
authors.affiliation: Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas, USA. shlomitriskin@yahoo.com
authors.forename: Shlomit
authors.initials: S
authors.lastname: Riskin-Mashiah
authors.forename: Michael A
authors.initials: MA
authors.lastname: Belfort
mesh_terms: D000328:Adult; D001794:Blood Pressure; D001921:Brain / Q000098:blood supply*; D002908:Chronic Disease; D005260:Female; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000503:physiopathology*; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D011225:Pre-Eclampsia / Q000209:etiology / Q000503:physiopathology*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies; D012039:Regional Blood Flow; D012307:Risk Factors; D018608:Ultrasonography, Doppler
chemical_list: D010100:Oxygen