Vascular reactivity and atheromatous plaques in post-menopausal women on tibolone treatment. Open prospective study with Doppler ultrasonography in internal carotid artery

Background: Arteriosclerosis is the main cause of ischaemic ictus. The middle cerebral and anterior cerebral arteries, which irrigate over 70% of the entire cerebral tissue, spring from the internal carotid. Additionally, it is in the extracraneal vessels that embolism, thrombosis and stenosis originate more frequently. Aim: To evaluate the variations in blood flow (pulsatility index: PI) and to assess the evolution of atherogenic lesions (thickening of the vascular intima and the presence of atheromatous plaques) in the internal carotid artery after tibolone therapy. Subjects and methods: A total of 116 healthy menopausal women were included in this open, prospective and comparative study. Of them, 101 subjects completed the 48 weeks follow-up. Subjects were allocated in two groups: group T (n = 55) received 2.5 mg/day of tibolone daily and group C (n = 61) was a free-treatment control group. To evaluate both resistance to blood flow and the existence and evolution of atheromatous plaques in the internal carotid, an ultrasonograph with a pulsed Doppler was used. The PI was used as the parameter of vascular tone. To study atherosclerotic lesions in the internal carotid artery, we used morphological criteria. Measurements were done before entering in the study, and at 12, 24, 36 and 48 weeks of treatment. Results: After tibolone treatment the PI in the internal carotid artery was observed markedly diminished. Moreover, tibolone reduces both the thickness and length of atheromatous plaque and the degree of vascular stenosis. Conclusion: tibolone administration reduced the carotid atheromatous plaque in thickness and length and improved cerebral perfusion.