Maternal cerebral hemodynamics in pregnancy-related hypertension. A prospective transcranial Doppler study

Aim To compare maternal cerebral hemodynamics, as assessed by transcranial Doppler studies, with the clinical and radiological findings in different t ypes of pregnancy-related hypertension and to determine their pathophysiolo gy. Methods A prospective study of 66 consecutive pregnant women with hypertens ive disorders (eclampsia, n = 3; pre-eclampsia, n = 41; isolated hemolysis, elevated liver enzymes, and low platelet count (HELLP)-syndrome, n = 12; p re-eclampsia superimposed on chronic hypertension, n = 5; chronic hypertens ion, n = 5) and 21 women with uncomplicated pregnancies. Mean blood flow ve locities (V-mean) were assessed serially by means of transcranial Doppler i n all basal arteries and correlated with changes in mean arterial blood pre ssure (MABP) and the clinical course. Results Patients with the pre-eclampsia/eclampsia syndrome showed significa ntly elevated V-mean values as compared to controls. In the course of the i llness V-mean over the whole length of all insonated basal arteries rose si multaneously. The three eclamptic patients showed the highest V-mean values (156, 182, 192 cm/s, respectively), of the middle cerebral artery (MCA) wh ile MABP was 135, 135, and 150 mmHg, respectively. In pre-eclamptic patient s the maximal V-mean MCA ranged from 80 (67, 93) to 145 (114, 252) cm/s [me dian (25th, 75th percentile)] depending on the severity of clinical present ation. In patients with isolated HELLP-syndrome changes in V-mean were eith er mild (5/12 cases) or absent (7/12 cases). Conclusions Considerable differences in cerebral hemodynamics were observed in the various types of pregnancy-related hypertensive disorders examined in this study. Our findings in patients with pre-eclampsia/eclampsia syndro me suggest a breakdown of autoregulation with hyperperfusion and vasogenic edema being the most probable pathophysiological mechanism.