Effects of oral and transdermal hormone replacement therapy on internal carotid artery pulsatility indices in postmenopausal women - A prospective, randomized, comparative study

Objective: To compare the effects of oral and transdermal hormone replaceme nt therapy on the internal carotid artery pulsatility index in postmenopaus al women. Study design: Thirty-seven women were randomized to six months of treatment with oral (n=19) or transdermal (n=18) sequential combined hormone replace ment therapy. The internal carotid artery pulsatility index was assessed by color Doppler ultrasound at baseline and after six months of treatment. Results: Carotid artery pulsatility indices were significantly lower than t he mean of 0.939 +/-0.139 at 0.860 +/-0.084 in the oral hormone replacement group and significantly lower than the mean of 0.928 +/-0.092 at 0.891 +/- 0.046 in the transdermal hormone replacement therapy group (P=.042) after s ix months of treatment. The mean changes in the carotid artery pulsatility index between the oral and transdermal hormone replacement groups were nons ignificant (-0.078 +/-0.131 and -0.037 +/-0.067, respectively; P=.53). Ther e was a significant negative correlation between the change in pulsatility index during treatment and baseline values in the carotid artery (r = -.81, P=.001), bid no correlation was found with time since menopause and serum estradiol level. Conclusion: Oral and transdermal sequential hormone replacement therapy are similarly effective at six months in reducing impedance to flow in the int ernal carotid artery.