Preeclampsia may cause both overperfusion and underperfusion of the brain: a cerebral perfusion based model.
BACKGROUND
The hypothesis was that low cerebral perfusion pressure is more common in women with mild preeclampsia as compared to those with severe preeclampsia, while high cerebral perfusion pressure is more common in women with severe preeclampsia than in women with mild preeclampsia.


METHODS
Prospective, observational study.


METHODS
University teaching hospitals.


METHODS
Transcranial Doppler ultrasound was used to measure the blood velocity in the middle cerebral arteries of 54 patients with mild preeclampsia and 44 patients with severe preeclampsia. Blood pressure was measured simultaneously. Cerebral perfusion pressure was calculated and plotted on the same axes as data from 63 normal pregnant women. Data outside of the 95% prediction limits were regarded as abnormal. All studies were prior to labor, and before volume expansion or treatment.


METHODS
Student's t-test, Mann Whitney U test, and Fisher's exact test as appropriate with two-tailed p<0.05.


METHODS
The number of patients in each group with cerebral perfusion pressure values outside the normal 95% prediction limits.


RESULTS
Almost the same number of women with mild (21/54=39%) and severe (15/44=34%) preeclampsia had measurements within the normal range (p=0.78). Mild preeclamptic women were more likely to have low (28/54=52%) rather than high cerebral perfusion pressure (p<0.001), while severe preeclamptics were more likely to have high cerebral perfusion pressure (26/44=59%) than low (p<0.001).


CONCLUSIONS
In preeclampsia the brain can be normally perfused, underperfused and over-perfused. Although many women with mild preeclampsia will have underperfusion (52%), and a significant number of women with severe preeclampsia will have overperfusion (59%), many preeclamptic women have cerebral perfusion within the normal range.
Belfort
M A
MA
Department of Obstetrics and Gynecology, University of Utah, Salt Lake City 84132, USA.
Grunewald
C
C
Saade
G R
GR
Varner
M
M
Nisell
H
H
D000328:Adult; D002560:Cerebrovascular Circulation; D004453:Echoencephalography / Q000379:methods; D005260:Female; D006801:Humans; D007427:Intracranial Pressure; D008962:Models, Theoretical; D011225:Pre-Eclampsia / Q000150:complications* / Q000000981:diagnostic imaging; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood* / Q000000981:diagnostic imaging; D017585:Ultrasonography, Doppler, Transcranial