Dynamic Cerebral Autoregulation in Pregnancy and the Risk of Preeclampsia

Abstract

Abstract-Preeclampsia may affect severely the cerebral circulation leading to impairment of cerebral autoregulation, edema, and ischemia. It is not known whether impaired autoregulation occurs before the clinical onset of preeclampsia, and whether this can predict the occurrence of preeclampsia. Seventy-two women at 25 to 28 weeks of gestation were studied. Control values were derived from 26 nonpregnant women. Dynamic properties of cerebral autoregulation (DCA) were measured in the middle and posterior cerebral artery using transcranial Doppler and transfer function analysis (phase and gain) of respiratory-induced 0.1 Hz hemodynamic oscillations. Uterine artery ultrasound was performed to search for a notch sign as an early marker of general endothelial dysfunction. All women were followed up until 6 weeks after delivery for the occurrence of preeclampsia. The autoregulation parameter gain did not differ between pregnant and nonpregnant women. Phase was slightly but significantly higher in pregnant women, indicating better DCA. Women with a notch sign did not show altered DCA. A history of preeclampsia during a previous pregnancy was associated with lower phase in middle cerebral artery and posterior cerebral artery (P<0.05 each). During follow-up, 9 women developed preeclampsia. None of the DCA parameters were associated with the occurrence of preeclampsia. In conclusion, DCA is well preserved during late midterm pregnancy, even in women with disturbed uterine blood flow. Yet, pregnant women with preeclampsia in a previous pregnancy seem to have poorer DCA. Although limited in statistical power, this study does not support DCA as a strong early risk marker of preeclampsia. (Hypertension. 2014;63:161-166.)

Placental ischemia in pregnant rats impairs cerebral blood flow autoregulation and increases blood-brain barrier permeability

“…For example, Zunker et al reported increased CBF velocities in the middle cerebral arteries of patients with preeclampsia or eclampsia (Zunker et al 1995). Moreover, patients who had preeclampsia in a previous pregnancy had poor dynamic CBF autoregulation (Janzarik et al 2014). A small clinical study showed that 46% of preeclamptic and eclamptic patients studied exhibited cortical and/or subcortical lesions involving the occipital lobe; 72% of which had a watershed distribution that was hypothesized to result from acute fluctuations in blood pressure (Demirtas ß et al 2005).…”

The Cerebral Circulation During Pregnancy: Adapting to Preserve Normalcy

“…However, these studies used animal models of pregnancy since such measurements in pregnant women are challenging and potentially dangerous. Studies in humans using non-invasive techniques to measure dynamic autoregulation during normal pregnancy have found improved or no change in CBF autoregulation in pregnant compared with nonpregnant women (47). To our knowledge, no study has determined the limits of CBF autoregulation during pregnancy, but it is important to understand because of the potential for acute hypotensive and hypertensive episodes that exist, especially during parturition.…”

Cerebral Autoregulation

“…It was suggested that this might explain why eclampsia can occur even without increases in blood pressure, van Veen et al (2013). In fact, phase (but not gain) has been found to be significantly higher in pregnant (25-28 weeks) women, compared to normal subjects, Janzarik et al (2014). In fact, phase (but not gain) has been found to be significantly higher in pregnant (25-28 weeks) women, compared to normal subjects, Janzarik et al (2014).…”