Objective: To study estimated cerebral perfusion pressure and its relation to headache and scotomata in women with pre-eclampsia.
Design: Prospective, observational study.
Setting: University teaching hospitals.
Population: Seventy-nine pre-eclamptic women with (n = 42) and without (n = 37) headache. Patients with scotomata were also studied separately.
Methods: Transcranial Doppler ultrasound was used to estimate the resistance index, pulsatility index, and estimated cerebral perfusion pressure in the middle cerebral artery. eCPP data were plotted on the same axes as the mean (and 5th and 95th% prediction limits) eCPP data from 63 normal pregnant women followed longitudinally through pregnancy. Data outside of the 95% prediction limits were regarded as abnormal. Data from the pre-eclamptic women were also expressed in terms of the number of standard deviations from the mean value established for normal pregnancy (multiples of the standard deviation: MOS). All studies were prior to labour, under similar conditions, and before volume expansion or treatment. Analysis of data was performed using Student's t test, Mann-Whitney U test, ANOVA, and Fisher's exact test with two-tailed P < 0.05, and receiver operating characteristic curve analysis with a one-tailed P < 0.05.
Main outcome measures: Resistance index, pulsatility index, and eCPP.
Results: Pre-eclamptic women with headache were much more likely to have abnormal eCPP (34/42; 88%) than those without headache (18/37; 49%), P = 0.004, OR 4.5 (95% CI 1.5 to 13.9). There were no differences in terms of MOS in the resistance index or pulsatility index between the two groups, but estimated perfusion pressure, expressed as multiples of the standard deviation in the group with headache, was significantly higher than in the women without. Headache was noted in both over-perfusion and under-perfusion states. Only women with headache had scotomata, and their presence was not related to the severity of the headache or any difference in resistance indices or eCPP.
Conclusions: Headache in women with pre-eclampsia is strongly associated with the presence of abnormal cerebral perfusion pressure. This information may be of use in clinical management.