THE EFFECT OF ESTROGEN ON THE FEMALE CARDIOVASCULAR-SYSTEM

Objective: To review the present state of knowledge regarding the effect of oestrogen on the female cardiovascular system (e.g. atherosclerosis, myocardial infarction, hypertension and thrombosis). Data sources: Over 100 articles (most published over the last 10 years) were reviewed. They included epidemiological, biochemical, physiological, animal and clinical studies which related to the effect oestrogens have on the cardiovascular system of postmenopausal women. These data contained a wide cross-section of results and outcomes and each study was summarised to provide the most relevant information. Where a particular study provided an opinion or result at variance with the majority opinion, that study has been discussed in greater detail. Study selection: All published papers which appeared to be relevant to an understanding of the clinical implications of oestrogen replacement therapy and its impact on the female cardiovascular system were included in this analysis. Some papers which appeared to repeat data and results previously published were not included. Data synthesis: The overwhelming weight of evidence from this literature review supports the concept that oestrogen reduces the risk of atherosclerosis and myocardial infarction. It also confirms that postmenopausal "natural" oestrogen is a vasodilating agent which will lead to a fall in blood pressure and an improvement in blood flow and the pulsatility index. Although oral oestrogen did appear to increase thrombogenic activity, there was no clinical evidence that "natural" oestrogen taken after the menopause increased the risk of venous thrombosis. Conclusions: The consensus of the published data is that oestrogen conveys a highly protective effect on the cardiovascular system of postmenopausal women. There will be a reduction of up to 50% in myocardial infarction and stroke, a reduction in the incidence of hypertension and an improvement in blood flow. Some of the data suggest that even for women who have suffered from an infarct, their long-term survival is enhanced by oestrogen therapy. The medical myth that oestrogen has a deleterious effect on the cardiovascular system of women is finally laid to rest.