Cerebral perfusion pressure and autoregulation in eclampsia - a case control study.

Background

Dynamic cerebral autoregulation and cerebral perfusion pressure are altered in preeclampsia compared to normotensive pregnancy, but the connections between dynamic cerebral autoregulation, cerebral perfusion pressure and cerebral complications in preeclampsia remain unclear.

Objectives

To assess dynamic cerebral autoregulation and cerebral perfusion pressure after delivery in women with eclampsia, preeclampsia both with and without severe features, and in normotensive women.

Study design

Prospective case control study at a large referral hospital in Cape Town, South Africa. Women were included at diagnosis (cases) or at admission for delivery (controls). Transcranial Doppler examinations with continuous non-invasive blood pressure measurements and end-tidal CO₂ were conducted for cases and controls after delivery. Cerebral perfusion pressure and dynamic cerebral autoregulation index were calculated and values were compared between groups.

Results

We included 16 women with eclampsia, 18 women with preeclampsia with severe features, 32 women with preeclampsia without severe features, and 21 normotensive women with uncomplicated pregnancies. Dynamic cerebral autoregulation was depressed in women with eclampsia; (autoregulation index 3.9; interquartile range 3.1-5.2) compared to all other groups (preeclampsia with severe features, autoregulation index 5.6; interquartile range 4.4-6.8, preeclampsia without severe features, autoregulation index 6.8; interquartile range 5.1-7.4 and normotensive controls, autoregulation index 7.1; IQR 6.1-7.9). Women with eclampsia had increased cerebral perfusion pressure (109.5 mm Hg; IQR 91.2-130.9) compared to women with preeclampsia without severe features and normotensive pregnancy (84 mm Hg; interquartile range 73.0-122.0 and 80.0 mm Hg; interquartile range 67.5-92.0, respectively), while there was no difference in cerebral perfusion pressure between women with eclampsia and women with preeclampsia with severe features (109.5 mm Hg; interquartile range 91.2-130.9 vs 96.5 mm Hg; interquartile range 75.8-110.5).

Conclusions

Cerebral perfusion pressure, and in particular dynamic cerebral autoregulation, are altered in eclampsia and may be important in the pathophysiological pathway and in addition constitute a therapeutic target in the prevention of cerebral complications in preeclampsia.