Cerebral Hemodynamics Analysis by Doppler Ultrasound in Chronically Hypertensive Pregnant Women

Abstract

Objective: To study the arterial blood flow of the carotid and vertebral systems during pregnancy in women with chronic hypertension via Doppler ultrasound and to compare the results with those obtained for normotensive pregnant women. Design: A prospective cohort study. Setting: Maternal care tertiary center; RJ Brazil. Population: 68 chronic hypertension pregnant women and 223 normotensive pregnant women. Methods: Doppler ultrasound was used to evaluate Doppler velocimetry indices of the common carotid artery, internal carotid artery, and the vertebral artery. We studied the peak systolic velocity (PSV), resistance index (RI), pulsatility index (PI) and diameter of the arteries. A sample of 68 pregnant women with chronic hypertension was compared to a group of 223 normotensive pregnant women. Main outcome measures: Doppler velocimetry indices. Results: There were no significant differences between the studied parameters for normotensive pregnant women and those of pregnant women with chronic hypertension. Among the variables that influenced arterial blood flow, gestational age was the only variable that was statistically significant, showing an increase in diameter and a decrease in resistance index with advancing gestation. Conclusions: Chronic hypertension does not alter the cerebral hemodynamics of pregnant women. However, protective brain microcirculation effects, such as hypertrophy, were not found in hypertensive pregnant women. The physiological changes of pregnancy may prevent or reverse these protective effects, which may predispose the brain to complications related to an acute increase in blood pressure.