Ultrasonographic blood flow measurement in the carotid arteries in postmenopausal women

A Systematic Review and Meta-Analysis Examining Whether Changing Ovarian Sex Steroid Hormone Levels Influence Cerebrovascular Function

Sex differences in cerebrovascular disease rates indicate a possible role for ovarian sex steroid hormones in cerebrovascular function. To synthesise and identify knowledge gaps, a systematic review and meta-analysis was conducted to assess how ovarian sex steroid hormone changes across the lifespan affect cerebrovascular function in women. Three databases (EMBASE, MEDLINE and Web of Science) were systematically searched for studies on adult cerebrovascular function and ovarian sex steroid hormones. Forty-five studies met pre-defined inclusion criteria. Studied hormone groups included hormone replacement therapy (HRT; n = 17), pregnancy (n = 12), menstrual cycle (n = 7), menopause (n = 5), oral contraception (n = 2), and ovarian hyperstimulation (n = 2). Outcome measures included pulsatility index (PI), cerebral blood flow/velocity (CBF), resistance index (RI), cerebral autoregulation, and cerebrovascular reactivity. Meta-analysis was carried out on HRT studies. PI significantly decreased [−0.05, 95% CI: (−0.10, −0.01); p = 0.01] in post-menopausal women undergoing HRT compared to post-menopausal women who were not, though there was considerable heterogeneity (I² = 96.8%). No effects of HRT were seen in CBF (p = 0.24) or RI (p = 0.77). This review indicates that HRT improves PI in post-menopausal women. However, there remains insufficient evidence to determine how changing ovarian sex steroid hormone levels affects cerebrovascular function in women during other hormonal phases (e.g., pregnancy, oral contraception).

Effects of different postmenopausal hormone therapy regimens on cerebral blood flow and cognitive functions

INTRODUCTION

The purpose of this study was to compare the effects of different postmenopausal hormone therapy regimens, namely conjugated equine estrogens (CEE), CEE plus medroxyprogesterone acetate (MPA), tibolone, and raloxifene on cerebral blood flow and cognitive functions.

METHODS

A total of 64 healthy postmenopausal women admitted to the Department of Obstetrics and Gynecology, Cumhuriyet University, Turkey were included in this study. Patients were divided into five groups with respect to the treatment protocols: CEE 0.625 mg/day (n=13); CEE 0.625 mg/day + MPA 2.5 mg/day (n=14); tibolone 2.5 mg/day (n=11); raloxifene 60 mg/day (n=9); and control (n=17). The CEE group included only women with surgical menopause. Those who were on hormonal therapy, who had previously used hormonal therapy, who had neurological disorders, or who did not accept the longterm follow-up were excluded from the study. Demographic and clinic characteristics were recorded. Before starting the therapy regimens, cerebral blood flow was evaluated by internal carotid artery and middle cerebral artery peak systolic velocity, and pulsatility index measurements via Doppler ultrasonography. Cognitive functions were evaluated by the Standardized Mini-Mental Test. The mean follow-up period was 10.9+/-2.4 months, ranging between 8 and 16 months. After the follow-up period, the cerebral blood flow, and cognitive function of each woman was re-evaluated.

RESULTS

Demographic and clinical characteristics of the women were not significantly different between the study groups (P>0.05). There were no significant differences between the pretreatment and posttreatment values for cerebral blood flow indices and cognitive function scores in any of the study groups (P>0.05).

CONCLUSION

Different postmenopausal hormone therapy regimens have not revealed any significant effects on either cerebral blood flow or cognitive function.

Effects of tibolone on blood flow resistance and intima-media thickness of the carotid arteries: effect of time since menopause

OBJECTIVE

The aim of this prospective study was to evaluate the effects of tibolone on carotid atherosclerosis in healthy postmenopausal women.

METHODS

Twenty-five healthy postmenopausal women were included in the study. Patients received tibolone 2.5 mg daily for 6 months. Resistance indices of the common carotid artery (CCA), internal carotid artery (ICA), external carotid artery (ECA) and vertebral arteries, and intima-media thickness of the CCA were measured both at baseline and at the end of the study with ultrasonography.

RESULTS

No significant differences were observed in the resistance indices of the CCA, ICA, ECA and vertebral arteries, as well as intima-media thickness of CCA at 6 months in comparison with baseline. Tibolone significantly improved the intima-media thickness of the CCA of women who were less than 18 months since menopause.

CONCLUSION

Overall, these results demonstrate no significant effects of tibolone on either intima-media thickness or blood flow resistance in the carotid arteries in postmenopausal women. However, the results suggest that tibolone may have a positive effect on the vascular system if commenced within 18 months since menopause; this warrants further investigation.

Effect of Aerodiol administration on cerebral blood flow volume in postmenopausal women

OBJECTIVE

The aim of the study was to evaluate the acute effect of the intranasal 17beta-estradiol (Aerodiol, Servier, Chambray-les-Tours, France) administration on cerebral blood flow (CBF) volume.

METHODS

Eighteen healthy women who had been natural postmenopausal for at least 1 year were enrolled in the study. We conducted an experimental, randomized, placebo-controlled, crossover, double-blinded study of the acute effect of 17beta-estradiol on the internal carotid artery (ICA), vertebral artery (VA) and, CBF volume using color duplex sonography.

RESULTS

There were significant increases in the ICA, VA flow volumes and CBF volume after 17beta-estradiol administration compared to placebo measurements. However, there was no statistically significant difference in flow velocities or pulsatility indices.

CONCLUSION

Nasal 17beta-estradiol administration in postmenopausal women causes significant increases in CBF volume due to its vasodilatatory effect on ICA and VA.

Carotid and uterine vascular resistance in short-term hormone replacement therapy postmenopausal users

OBJECTIVE

To compare the short-term effects of oral hormone replacement therapy (HRT) and placebo on carotid and uterine vascular impedance.

METHODS

80 postmenopausal women selected from the outpatient clinic of the Hospital Leonor Mendes de Barros in São Paulo, Brazil, were randomized to oral HRT (estradiol 2 mg/norethisterone acetate 1 mg-Kliogest(r)) or placebo. Carotid and uterine arteries pulsatility indices (PIs) were assessed by color Doppler at baseline, after 4 and 12 weeks of treatment. Seventy-six women completed the trial, 38 in each group.

RESULTS

The carotid PI did not decrease significantly in either group. In the uterine arteries, the drop in PI was steeper and greater for HRT women. Drops occurred despite the supposed counteracting effect of norethisterone acetate. In placebo group, there was no significant difference between 4 and 12 weeks of treatment compared with the baseline. The results did not change when analyzed in a real treatment approach.

CONCLUSION

Oral continuous HRT are effective at 12 weeks in reducing impedance to flow in uterine, but not in carotid circulation. These results suggest that the effects of HRT vary by vascular site, and do not have a detectable short-term vascular effect in the carotid area.

Effects of raloxifene on carotid blood flow resistance and endothelium-dependent vasodilation in postmenopausal women

Raloxifene is one of the most important selective estrogen receptor modulators currently employed for the treatment of postmenopausal osteoporosis. However, it has also been suggested that this compound affects the vascular system. We evaluated both carotid blood flow resistance and endothelium-dependent vasodilation in 50 healthy postmenopausal women randomly assigned to receive, in a double blind design, either raloxifene (60 mg per day; N=25 subjects) or placebo (N=25 subjects) for 4 months. Indices of carotid blood flow resistance, such as the pulsatility index (PI) and resistance index (RI), as well as the flow-mediated brachial artery dilation were measured both at baseline and at the end of treatment. Changes in PI were -1.86+/-2.24 and -2.15+/-2.22% after placebo and raloxifene treatment, respectively, with no significant differences between groups. Changes in RI were -0.77+/-1.72 and -1.81+/-1.54% after placebo and raloxifene treatment, respectively, with no significant differences between groups. At the end of the treatment period, the increments in artery diameter measured after the flow stimulus were 10.79+/-2.39 and 6.70+/-1.23% for placebo and raloxifene, respectively, with no significant differences between groups. These results demonstrate no significant effects of raloxifene on either carotid blood flow resistance or brachial artery flow-mediated dilation in postmenopausal women.

Arterial stiffness is not improved in long-term use of estrogen

OBJECTIVE

The purpose of this study was to compare arterial stiffness in long-term users of estrogen who were postmenopausal, age-matched women who did not use estrogen, and women of fertile age.

STUDY DESIGN

In this clinical cross-sectional study, carotid, femoral, and aortic stiffness (estimated as elastic modulus and stiffness beta index) were assessed by ultrasonic phase-locked echo-tracking in 17 women who were postmenopausal and who were treated with 17 beta-estradiol implants (mean age, 68.8 years; mean duration of treatment, 20 years), 17 age-matched (+/-1 year) untreated women, and 20 women in the fertile age period.

RESULTS

Compared with women of fertile age, both postmenopausal groups had significantly higher stiffness elastic modulus and stiffness beta index (carotid, P <.001; femoral, P <.05; aorta, P <.001). However, for all 3 arteries, both stiffness indices were similar in estrogen users and nonusers and did not differ significantly. These results remained after an adjustment for systolic blood pressure, body mass index, and low-density lipoprotein cholesterol levels.

CONCLUSION

These data indicate that the arterial stiffening that is related to aging/menopause is not substantially affected by long-term estrogen therapy.