Flow resistance in carotid and middle cerebral arteries in postmenopausal women: a comparative study of tibolone and continuous combined hormone replacement therapy.
OBJECTIVE
The study sought to compare the vascular resistance and serum lipids of postmenopausal women assigned to tibolone therapy or continuous combined hormone replacement therapy.


METHODS
This was a 6-month, prospective, single-blind, single-center, randomized study. A total of 50 healthy postmenopausal women were enrolled. At study end, 40 women had completed a 6-month follow-up. The first group (23 subjects) received conjugated equine estrogens (CEE) 0.625 mg/day and medroxyprogesterone acetate (MPA) 5 mg/day. The second group (17 subjects) received tibolone 2.5 mg/day. The pulsatility and resistance indexes of the carotid and middle cerebral arteries, and serum lipid profiles were monitored.


RESULTS
Comparisons demonstrated that there were no significant differences between the groups in terms of changes in the pulsatility index (PI) and the resistance index (RI) of the common carotid artery (CCA), internal carotid artery (ICA), and middle cerebral artery (MCA) within the study period. Both treatments effectively reduced the total cholesterol level and with no significant differences found between the two regimens. However, in comparing the two groups, we found that high-density lipoprotein (HDL) cholesterol levels were significantly lower in the tibolone group at either 3 months or 6 months after treatment, whereas a significantly higher triglycerides level was observed in the CEE + MPA group after 3 months of treatment. Low-density lipoprotein (LDL) cholesterol levels indicated no significant differences between the two groups after treatment.


CONCLUSIONS
The study demonstrated that major neck and cerebral vascular impedance was not influenced significantly by either regimen. Nonetheless, lipid profiles were affected differently by tibolone and by continuous combined CEE + MPA. However, whether or not these findings might modify cardiovascular risk is still unknown.
Pan
H-A
HA
Department of Obstetrics, National Cheng Kung University Hospital, Tainan, Taiwan.
Wang
S-T
ST
Chen
C-H
CH
Pai
M-C
MC
Wu
M-H
MH
Huang
K-E
KE
D001783:Blood Flow Velocity; D001921:Brain / Q000098:blood supply; D017536:Carotid Artery, Common / Q000187:drug effects* / Q000502:physiology; D002343:Carotid Artery, Internal / Q000187:drug effects / Q000502:physiology; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D003326:Coronary Circulation / Q000187:drug effects; D004334:Drug Administration Schedule; D020847:Estrogen Receptor Modulators / Q000494:pharmacology; D015914:Estrogen Replacement Therapy; D004966:Estrogens, Conjugated (USP) / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006801:Humans; D017258:Medroxyprogesterone Acetate / Q000008:administration & dosage / Q000494:pharmacology*; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000187:drug effects*; D009652:Norpregnenes / Q000494:pharmacology*; D017698:Postmenopause; D011446:Prospective Studies; D011673:Pulsatile Flow / Q000187:drug effects; D016037:Single-Blind Method; D016896:Treatment Outcome; D014280:Triglycerides / Q000097:blood; D014655:Vascular Resistance / Q000187:drug effects* / Q000502:physiology
D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D020847:Estrogen Receptor Modulators; D004966:Estrogens, Conjugated (USP); D009652:Norpregnenes; D014280:Triglycerides; D002784:Cholesterol; D017258:Medroxyprogesterone Acetate; C027385:tibolone