Carotid artery stiffening does not explain baroreflex impairment in pre-eclampsia

Abstract

Stiffening of the barosensory vessel wall in hypertension has been suggested to play a role in the associated baroreflex impairment. The carotid distensibility-BRS (baroreflex sensitivity) relationship, however, has not been studied in pre-eclampsia, a condition where hypertension is spontaneously reversible. Twelve normotensive pregnant women and 12 patients with pre-eclampsia matched for maternal age and week of gestation were studied in the third trimester and 3 months postpartum. Carotid artery diastolic diameter and pulsatile distension was measured by echo-wall tracking and carotid pulse pressure by applanation tonometry, and the carotid distensibility coefficient was calculated. Spontaneous BRS was determined by the sequence and spectral methods from 10 min continuous recording of ECG and finger arterial blood pressure. In the third trimester, carotid distensibility was lower in patients with pre-eclampsia than in normotensive pregnant women (2.47+/-0.17 compared with 4.08+/-0.16 x 10(-3)/mmHg); postpartum, it increased moderately in patients, but remained below normotensive values (3.25+/-0.12 compared with 4.25+/-0.19 x 10(-3)/mmHg). In the third trimester, both patients and healthy pregnant women had equally low BRS values; postpartum, the various BRS indices increased markedly (by 60-190%) and to the same level in both groups. No correlation was found between changes in carotid artery distensibility and those in BRS from the third trimester to postpartum period in patients and healthy pregnant women. The lack of association between changes in carotid distensibility and BRS suggest that stiffening of the carotid artery in pre-eclampsia is not responsible for baroreflex dysfunction.

The association between preeclampsia and arterial stiffness

“…Studies assessing stiffness index in preeclamptic women found similar results [43,47]. Additional records identified through other sources (n = 5)…”

“…Mersich et al [47] found stiffness index to be significantly elevated in preeclamptic women as compared with normotensive controls during the third trimester and 3 months postpartum.…”

“…Five longitudinal studies assessed changes in arterial stiffness prior to, during, and after preeclamptic pregnancy [31,32,[46][47][48].…”

Pregnancy and the endocrine regulation of the baroreceptor reflex

“…Reflex responses to atrial stretch are also blunted (51,94,95,103), which may contribute to retention of the expanded blood volume. The depressed baroreflex function observed during normal pregnancy appears to worsen in pregnancy-associated diseases such as preeclampsia (69,129,137,175,195). Interestingly, early gestational measurements of depressed baroreflex sensitivity in conjunction with reduced uterine perfusion have been proposed as a means to predict the ultimate development of this disease (194).…”

Vascular ultrasound in obstetrics

“…Recent progress of the ultrasound equipment enabled us to assess the vascular wall structure and property. Marsich and colleagues measured the vascular wall distensibility of the carotid artery calculated from the blood pressure change and vascular diameter change using an echo-tracking system, and they reported that in patients with pre-eclampsia the carotid artery distensibility was significantly lower than that in normotensive pregnant women [5]. They also reported that in normotensive pregnant women no correlation was found between changes in carotid artery and systemic artery in elastic parameters of the vascular wall [6].…”