Transcranial Doppler findings of cerebral vasospasm in preeclampsia.

The objective of this study was to evaluate the effect of preeclampsia and its severity on maternal mean middle cerebral artery blood flow velocity (mean MCA-CBFV) using transcranial doppler sonography (TCD), as well as the effect of magnesium on mean MCA-CBFV in preeclampsia. This study used a prospective, comparative design. TCD was used to examine maternal mean MCA-CBFV in both healthy subjects (controls) and preeclamptic subjects (cases). The two groups were similar in age, gestational age, and parity. Healthy subjects were categorized into three groups: Group I, 6-14 weeks, n = 10; Group II, 24-40 weeks, n = 27; Group III, postpartum n = 15, 12-36 h. Serial TCD examinations of the middle cerebral artery were completed in 21 preeclamptic subjects at four different points in time: Time I is an initial measurement before delivery; Time 2 is also before delivery but after magnesium had been administered. Time 3 is postpartum while on magnesium (12-24 h), Time 4 is postpartum off magnesium, (24-48 h). Preeclamptic subjects had significantly increased mean MCA-CBFV when compared to healthy subjects: antepartum (mean 78.2 vs. 55.1 cm/sec, P < 0.0005); postpartum (mean 101.3 vs. 69.8 cm/sec, P < 0.0001). Severe preeclamptics had significantly higher mean MCA-CBFV than mild preeclamptics at each point in time: Time 1: P < 0.016; Time 2: P < 0.040; Time 3: P < 0.002; and Time 4: P < 0.028. These data support the theory that cerebral vasospasm of the smaller diameter vessels is a major component of preeclampsia.