MPA and postmenopausal coronary artery atherosclerosis revisited

Estrogen effects on arteries vary with stage of reproductive life and extent of subclinical atherosclerosis progression

The past several years have been marked by confusion and controversy concerning whether estrogens are cardioprotective. The issue is of utmost public health importance because coronary heart disease (CHD) remains the leading cause of death among postmenopausal women. Fortunately, a unifying hypothesis has emerged that reproductive stage is a major determinant of the effect of estrogens on atherosclerosis progression, complications, and plaque vulnerability.

PREMENOPAUSAL YEARS

Premenopausal atherosclerosis progression seems to be an important determinant of postmenopausal atherosclerosis and thus the risk for CHD. Clearly, plasma lipids/lipoproteins influence this progression; however, estradiol deficiency seems to be the major modulator. Both monkeys and women with premenopausal estrogen deficiency develop premature atherosclerosis, an effect that can be prevented in both species by estrogen-containing oral contraceptives.

PERIMENOPAUSAL/EARLY POSTMENOPAUSAL YEARS

During this stage, there are robust estrogen benefits. Monkeys given estrogens immediately after surgical menopause have a 70% inhibition in coronary atherosclerosis progression. Estrogen treatment prevented progression of atherosclerosis of women in the Estrogen in the Prevention of Atherosclerosis Trial. A meta-analysis of women younger than 60 years given hormone therapy had reduced total mortality (relative risk = 0.61, 95% CI: 0.39-0.95).

LATE POSTMENOPAUSAL YEARS

This stage is one in which there are no or possible deleterious estrogen effects. Monkeys lose CHD benefits of estrogens when treatment is delayed. The increase in CHD events associated with initiating hormone therapy 10 or more years after menopause seems to be related to up-regulation of the plaque inflammatory processes and plaque instability and may be down-regulated by statin pretreatment.

Reprint of "Use of medroxyprogesterone acetate for hormone therapy in postmenopausal women: Is it safe?"

Medroxyprogesterone acetate (MPA) has been in clinical use for over 30 years, and was generally considered to be safe until the results of long-term studies of postmenopausal hormone therapy (HT) using treatment with conjugated equine estrogens (CEE) combined with MPA and CEE alone suggested that MPA, and perhaps other progestogens, may play a role in the increased risk of breast cancer and cardiovascular diseases. This review examines critically the safety of MPA in terms of breast cancer and cardiovascular disease risk, and its effects on brain function. Research into mechanisms by which MPA might cause adverse effects in these areas, combined with the available clinical evidence, suggests a small increase in relative risk for breast cancer and stroke, and a decline in cognitive function, in older women using MPA with an estrogen for postmenopausal HT. However, short-term (less than 5 years) use of MPA with an estrogen in the years immediately after the onset of menopause for the management of vasomotor symptoms does not appear to be associated with any increased risk of these disorders.

Use of medroxyprogesterone acetate for hormone therapy in postmenopausal women: is it safe?

Medroxyprogesterone acetate (MPA) has been in clinical use for over 30 years, and was generally considered to be safe until the results of long-term studies of postmenopausal hormone therapy (HT) using treatment with conjugated equine estrogens (CEE) combined with MPA and CEE alone suggested that MPA, and perhaps other progestogens, may play a role in the increased risk of breast cancer and cardiovascular diseases. This review examines critically the safety of MPA in terms of breast cancer and cardiovascular disease risk, and its effects on brain function. Research into mechanisms by which MPA might cause adverse effects in these areas, combined with the available clinical evidence, suggests a small increase in relative risk for breast cancer and stroke, and a decline in cognitive function, in older women using MPA with an estrogen for postmenopausal HT. However, short-term (less than 5 years) use of MPA with an estrogen in the years immediately after the onset of menopause for the management of vasomotor symptoms does not appear to be associated with any increased risk of these disorders.

Menopausal hot flushes and vascular health

Hot flushes are complained of by approximately 75% of all postmenopausal women, and hormone therapy (HT) is the most effective way to alleviate them. Hot flushes are characterized by altered vascular function and sympathetic nervous system activity. Hot flushes occurred more often in women attending large, non-randomized observational studies (e.g. Nurses' Health Study), where HT use protected against cardiovascular disease (CVD). However, they were absent (or mild) in randomized HT trials where HT use was accompanied with an elevated risk for CVD. Hot flushes, if a factor for cardiovascular health, could partly explain the conflict between observational and randomized trials. Several cross-sectional studies imply that hot flushes are detrimental to the cardiovascular system. However, the data are not uniform, and hot flushes were recalled retrospectively or during HT use. In our prospective study hot flushes were accompanied with a vasodilatory effect during endothelial testing, and this was related to the severity of hot flushes. Night-time hot flushes were followed with transient rises in ambulatory blood pressure (BP). However, no effect of hot flushes on diurnal BP was detected. The use of estradiol showed no harmful effects on endothelial function in women with hot flushes, but in non-flushing women oral, but not transdermal, estradiol led to vasoconstrictive changes. Estradiol complemented with medroxyprogesterone acetate eliminated the vasoconstrictive effect of sole oral estradiol. Thus, both oral and transdermal estradiol are applicable in flushing women, whereas a transdermal route should be favored in non-flushing women if used e.g. for bone protection.

Vasomotor hot flushes and 24-hour ambulatory blood pressure in normotensive women: A placebo-controlled trial on post-menopausal hormone therapy

BACKGROUND

Blood pressure (BP) is one of the most powerful determinants of cardiovascular risk in women. This risk may differ between post-menopausal women with and without vasomotor hot flushes, possibly indicating different vascular responses to hormone therapy (HT). Thus, we compared in a clinical trial the effect of HT on ambulatory BP in normotensive, recently post-menopausal women with or without severe hot flushes.

METHODS

A total of 147 women recorded prospectively their hot flushes for 2 weeks; 70 women were symptomatic (>or=7 moderate/severe hot flush episodes/day), whereas 77 women were defined as asymptomatic (<or=3 mild hot flush episodes/day). Women were treated for 6 months with either transdermal estradiol, oral estradiol with or without medroxyprogesterone acetate, or placebo.

RESULTS

In symptomatic women decreases in BPs were seen during estradiol use. In contrast, in asymptomatic women receiving oral but not transdermal estradiol, increases in 24-h and day-time systolic and diastolic BPs were encountered.

CONCLUSION

Hot flushes modify the HT-mediated responses in ambulatory BP. In asymptomatic women oral but not transdermal estradiol show potentially harmful cardiovascular effect by increasing BP. Our results give additional justification to prescribing HT primarily for the treatment of troublesome hot flushes and avoiding HT in women without vasomotor symptoms.

Effect of hot flushes on vascular function: a randomized controlled trial

OBJECTIVE

To compare the vascular responses to hormone therapy in women with and without hot flushes.

METHODS

We randomly assigned 143 healthy, recently postmenopausal women (mean age 52.4+/-0.2 years, time since menopause 19.5+/-0.9 months) with intolerable hot flushes (more than seven moderate/severe episodes per day) or tolerable hot flushes (fewer than three mild episodes per day) to receive 1 mg of transdermal estradiol gel, oral estradiol (2 mg) with and without daily medroxyprogesterone acetate, or placebo for 6 months. Vascular function was assessed by pulse-wave analysis and endothelial function testing with nitroglycerin and salbutamol challenges.

RESULTS

Hot flushes did not affect the changes in arterial or aortic stiffness or endothelial function in response to various forms of hormone therapy. However, in women with tolerable hot flushes, oral estradiol caused a decrease of 13.2% (P=.028) in the time to the first systolic peak (dependent on the rapid phase of ventricular ejection) after nitroglycerin. In addition, the time to the reflected wave (dependent on pulse-wave velocity) after nitroglycerin was decreased by 8.4% (P=.018). These effects were not seen in women with intolerable hot flushes or with the other treatment regimens.

CONCLUSION

Women without troublesome hot flushes are susceptible to unfavorable vascular effects after oral estrogen treatment, resulting in less compliant vasculature.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT00668603.

LEVEL OF EVIDENCE

I.

Coronary heart disease of females: lessons learned from nonhuman primates

The cynomolgus monkey model has contributed to significant advances regarding the understanding of coronary artery atherosclerosis of females. There are currently 8 million women in the United States living with heart disease, necessitating further study and understanding of this leading cause of morbidity and mortality for postmenopausal women. Specifically, studies involving the monkey model have allowed greater understanding of the effect of the stage of reproductive life, time since menopause, and the extent of subclinical atherosclerosis as determinates of estrogen-mediated effects on arteries. Utilizing the commonalities among monkeys and human beings, these studies have shown that postmenopausal atherosclerosis is associated with the premenopausal reproductive timeframe. In addition, monkey studies have shown that estrogen deficiency during the premenopausal stage is extremely relevant regarding the progression of atherosclerosis. After several postmenopausal years, however, studies have shown that estrogen has no beneficial effects on atherosclerosis progression and may, in fact, be deleterious. Studies using the monkey model are currently underway to investigate further uses and possibilities of postmenopausal hormone therapy for treating menopausal symptoms while protecting the breast and uterus and inhibiting the progression of coronary artery atherosclerosis. These studies will hopefully clarify the role of estrogen and eliminate the need for the possibly harmful progestin effects through the use of a highly selective estrogen receptor modulator.

Long-Term Prevention with Hormone-Replacement Therapy after the Menopause: Which Women should be Targeted?

For decades, hormone-replacement therapy (HRT) was considered safe and was the first choice in prevention of postmenopausal osteoporosis induced by estrogen deficiency. Numerous experimental and epidemiological studies further supported a protective effect of exogenous female sex hormones on atherogenesis and coronary heart disease (CHD) in women after the menopause. However, the fact that these promising results were not translated into lower incidences of CHD events in hormone-treated women compared with placebo in subsequent, large, randomized studies of healthy subjects as well as women with known CHD raised a very intense debate concerning the safety of HRT in terms of cardiovascular risk. A critical mass of data points toward a protective influence of HRT on cardiovascular disease end points in early postmenopausal women, but increased harm in elderly women, especially those with abdominal adiposity or metabolic syndrome. Once the quasi-hysterical reaction to the largest of the randomized studies (the Women's Health Initiative) has abated, a future strategy should be to concentrate on identifying those relatively few individuals who are not suitable for HRT, as HRT still remains the most thoroughly investigated pharmacological prevention strategy of osteoporosis.

Correlation between hormonal and lipid status in women in menopause

It is widely accepted that menopause leads to changes in hormonal status, metabolism and lipid profile. The aim of this study was to analyze the influence of menopause on the concentrations of lipids, lipoproteins and, the influence of estradiol, progesterone, FSH, LH on lipid profile in menopausal women as well. The menopausal women had higher but non-significant (p>0,05) concentrations of total cholesterol, VLDL, LDL, and triglycerides than women with regular menstruation. The concentration of HDL was significantly lower in menopausal women than in women with regular menstruation (p<0,05). Also, the concentration of apolipoprotein B was significantly higher in menopausal women (p<0,05), but the concentrations of apolipoprotein and lipoprotein (a) were lower but without significance (p>0,05). Estrogen concentration has significant negative correlation with VLDL and triglycerides (p<0,05) and significant positive correlation with HDL (p<0,05) in menopausal women. Progesterone concentration has shown no correlation with concentrations of lipids and lipoproteins in menopause. We can conclude that menopause leads to changes in lipid profile by reducing HDL, and elevating apolipoprotein B levels, thus increasing the risk for cardiovascular disease. These changes were caused by reduction of estrogen concentrations in menopause.

Vascular effects of estrogen and progestins and risk of coronary artery disease: importance of timing of estrogen treatment

The effects of estrogen and progestins on the vascular wall have drawn major medical attention, and significant controversy over various studies has been developed. Several experimental and observational studies have shown cardioprotective effects; however, prospective randomized trials showed an increase in cardiovascular events in postmenopausal women on estrogen/ medroxyprogesterone acetate treatment. The most significant parameter for cardiovascular benefit of estrogen seems to be the interval since the onset of menopause. In the early postmenopausal years, estrogen has beneficial effects on the vascular wall by inhibition of atherosclerosis progression, whereas in the late postmenopause, adverse effects like upregulation of the plaque inflammatory processes and plaque instability may develop. The effects of progestins on the cardiovascular system are not as clear and may differ according to the choice of progestins that is used. The aim of this review is to summarize the effects of estrogen and progestins on the vascular wall and their clinical implications.

Estrogen effects on arteries vary with stage of reproductive life and extent of subclinical atherosclerosis progression

The past several years have been marked by confusion and controversy concerning whether estrogens are cardioprotective. The issue is of utmost public health importance because coronary heart disease (CHD) remains the leading cause of death among postmenopausal women. Fortunately, a unifying hypothesis has emerged that reproductive stage is a major determinant of the effect of estrogens on atherosclerosis progression, complications, and plaque vulnerability. PREMENOPAUSAL YEARS: Premenopausal atherosclerosis progression seems to be an important determinant of postmenopausal atherosclerosis and thus the risk for CHD. Clearly, plasma lipids/lipoproteins influence this progression; however, estradiol deficiency seems to be the major modulator. Both monkeys and women with premenopausal estrogen deficiency develop premature atherosclerosis, an effect that can be prevented in both species by estrogen-containing oral contraceptives. PERIMENOPAUSAL/EARLY POSTMENOPAUSAL YEARS: During this stage, there are robust estrogen benefits. Monkeys given estrogens immediately after surgical menopause have a 70% inhibition in coronary atherosclerosis progression. Estrogen treatment prevented progression of atherosclerosis of women in the Estrogen in the Prevention of Atherosclerosis Trial. A meta-analysis of women younger than 60 years given hormone therapy had reduced total mortality (relative risk = 0.61, 95% CI: 0.39-0.95). LATE POSTMENOPAUSAL YEARS: This stage is one in which there are no or possible deleterious estrogen effects. Monkeys lose CHD benefits of estrogens when treatment is delayed. The increase in CHD events associated with initiating hormone therapy 10 or more years after menopause seems to be related to up-regulation of the plaque inflammatory processes and plaque instability and may be down-regulated by statin pretreatment.

Options for hormone therapy in women who have had a hysterectomy

OBJECTIVE

To review postmenopausal hormone therapy for women who have undergone hysterectomy with or without bilateral oophorectomy and to make clinical recommendations regarding changes in regimens compared with those for women with their uterus in place.

DESIGN

We conducted a literature review, including a review of current guidelines.

RESULTS

When the uterus is absent, estrogen treatment is all that is needed when hot flashes and/or genital atrophic symptoms are associated with surgical or natural menopause. Reasons to add a progestogen to an estrogen-only therapy regimen after hysterectomy include the need to reduce the risk for unopposed estrogen-dependent conditions, chief among which are endometriosis or endometrial neoplasia. Multiple lines of evidence suggest that regimens containing both estrogen and progestogen versus estrogen alone are associated with a greater relative risk of breast cancer without additional improvement in relief of hot flashes or vaginal symptoms. When a bilateral oophorectomy is performed before natural menopause, the onset of menopausal symptoms, primarily vasomotor symptoms, genital tract atrophy, and/or a decline in sexual function, is rapid, and the symptoms are more severe. Thus, the need for a decision on the use of hormone therapy is accelerated.

CONCLUSIONS

The decision to use or not use menopausal hormone therapy in women without a uterus should involve an individualized risk/benefit analysis just as it should when the uterus is present. After hysterectomy, for most patients, current literature results favor not including a progestogen. Data suggest an attenuation of the potential cardiovascular benefit of estrogen therapy in this situation, yet no better protection against bone fractures and an increase in the risk for breast cancer when both estrogen and progestogen are used.

Hormone replacement therapy and the cardiovascular system lessons learned and unanswered questions

Cardiovascular disease is the leading cause of death among women in the U.S., exceeding breast cancer mortality in women of all ages. Women present with cardiovascular disease a decade after men, and this has been attributed to the protective effect of female ovarian sex hormones that is lost after menopause. Animal and observational studies have shown beneficial effects of hormone therapy when it is initiated early in the perimenopausal period or before the development of significant atherosclerosis. However, randomized, placebo-controlled trials in older women have not shown any benefit in either primary prevention or secondary prevention of cardiovascular events, with a concerning trend toward harm. This review outlines the lessons learned from the basic science, animal, observational, and randomized trials, and then summarizes yet-unanswered questions of hormone therapy and cardiovascular risk.

O endotélio na síndrome metabólica

O endotélio é responsável pela manutenção da homeostase vascular. Em condições fisiológicas, mantém o tônus vascular, o fluxo sangüíneo laminar, a fluidez da membrana plasmática, o equilíbrio entre coagulação e fibrinólise, a inibição da proliferação e da migração celulares e o controle da resposta inflamatória. A disfunção endotelial é definida como uma alteração do relaxamento vascular por diminuição da biodisponibilidade de fatores de relaxamento derivados do endotélio, principalmente o óxido nítrico (NO). Estas respostas vasomotoras anormais ocorrem na presença de inúmeros fatores de risco para a aterosclerose. A síndrome metabólica é considerada um estado de inflamação crônica que se acompanha de disfunção endotelial e ocasiona aumento na incidência de eventos isquêmicos cardiovasculares e elevada mortalidade. Essa revisão abordará o processo fisiológico de regulação da função vascular pelo endotélio, os métodos disponíveis para avaliação in vivo da disfunção endotelial e as terapias capazes de melhorar a função vascular e conseqüentemente minimizar o risco cardiovascular dessa síndrome tão prevalente no nosso meio.

A critique of the Women's Health Initiative hormone therapy study

OBJECTIVE

This review critiques The Women's Health Initiative (WHI) study, focusing on aspects of the study design contributing to the adverse events resulting in the study's discontinuation.

CONCLUSION(S)

Two aspects of the design contributed to the adverse events: [1] The decision to administer continuous combined conjugated equine estrogen (CEE)/medroxyprogesterone acetate (MPA) or E alone as a standard regimen to a population with little previous hormonal treatment, ranging in age from 50-79 years, who, because of their age, were predisposed to coronary and cerebral atherosclerosis. [2] Selection of an untested regimen of continuous combined CEE plus MPA, which we hypothesize, negated the protective effect of E on the cardiovascular and cerebrovascular systems. Multiple observational studies that preceded the WHI study concluded that the use of E alone and E plus cyclic (not daily) progestin combination treatments initiated in early menopause had beneficial effects. The therapeutic regimens resulted in prevention of atherosclerosis and reductions in coronary artery disease mortality. It is our conclusion that the WHI hormonal replacement study had major design flaws that led to adverse conclusions about the positive effects of hormone therapy. An alternative hormonal regimen is proposed that, on the basis of data supporting its beneficial cardiovascular effects, when initiated appropriately in a population of younger, more recently menopausal women, has promise to yield a more favorable risk/benefit outcome.

Effects of Transdermal Estrogen Replacement Therapy on Cardiovascular Risk Factors

The prevalence of hypertension and cardiovascular disease increases dramatically after menopause in women, implicating estrogen as having a protective role in the cardiovascular system. However, recent large clinical trials have failed to show cardiovascular benefit, and have even demonstrated possible harmful effects, of opposed and unopposed estrogen in postmenopausal women. While these findings have led to a revision of guidelines such that they discourage the use of estrogen for primary or secondary prevention of heart disease in postmenopausal women, many investigators have attributed the negative results in clinical trials to several flaws in study design, including the older age of study participants and the initiation of estrogen late after menopause.Because almost all clinical trials use oral estrogen as the primary form of hormone supplementation, another question that has arisen is the importance of the route of estrogen administration with regards to the cardiovascular outcomes. During oral estrogen administration, the concentration of estradiol in the liver sinusoids is four to five times higher than that in the systemic circulation. This supraphysiologic concentration of estrogen in the liver can modulate the expression of many hepatic-derived proteins, which are not observed in premenopausal women. In contrast, transdermal estrogen delivers the hormone directly into the systemic circulation and, thus, avoids the first-pass hepatic effect.Although oral estrogen exerts a more favorable influence than transdermal estrogen on traditional cardiovascular risk factors such as high- and low-density lipoprotein-cholesterol levels, recent studies have indicated that oral estrogen adversely influences many emerging risk factors in ways that are not seen with transdermal estrogen. Oral estrogen significantly increases levels of acute-phase proteins such as C-reactive protein and serum amyloid A; procoagulant factors such as prothrombin fragments 1+2; and several key enzymes involved in plaque disruption, while transdermal estrogen does not have these adverse effects.Whether the advantages of transdermal estrogen with regards to these risk factors will translate into improved clinical outcomes remains to be determined. Two ongoing clinical trials, KEEPS (Kronos Early Estrogen Prevention Study) and ELITE (Early versus Late Intervention Trial with Estradiol) are likely to provide invaluable information regarding the role of oral versus transdermal estrogen in younger postmenopausal women.

Cardiovascular alteration and treatment of hypertension: do men and women differ?

Cardiovascular disease is one of the most common causes of mortality affecting both men and women in industrialized nations. Sex-related differences have been well established with regard to heart and vascular function as well as cardiovascular disease processes. Nevertheless, the precise mechanisms of action behind these gender-related differences are poorly understood. Premenopausal women have a relatively lower arterial blood pressure compared to age-matched men and post-menopausal women, suggesting a role of ovarian hormones in blood pressure regulation. Sex-related differences in vasculature and neuroendocrine systems are also present that can affect hemostasis, vascular reactivity, and vascular tone. Treatment for cardiovascular disease and hypertension has been challenging and unsatisfactory. Men and women may require different antihypertensive regimens due to differences in the progression and presentation of hypertension. Additionally, hormone replacement therapy in postmenopausal women has been controversial, producing both beneficial and detrimental effects. Therefore, this review will focus on sex-related differences in the heart and vasculature, and treatments for cardiovascular disease, such as hypertension.

Medroxyprogesterone acetate and dihydrotestosterone induce coronary hyperreactivity in intact male rhesus monkeys

Coronary hyperreactivity (CH), characterized by persistent severe vasoconstrictions in response to vasoconstrictor challenge, is oppositely influenced by progesterone (P) and medroxyprogesterone acetate (MPA) treatment in surgically menopausal primates. In this study we tested whether multiweek MPA or dihydrotestosterone (DHT) exposure induced CH in intact male rhesus monkeys. Coronary angiographic experiments with intracoronary serotonin and the thromboxane A(2) analog U46619 stimulated brief vasoconstriction (for 1-3 min) in large epicardial coronaries in untreated male monkeys. In contrast, MPA- and DHT-treated monkeys displayed long-duration constrictions (>5 min), with significantly greater reductions in the minimal diameters of epicardial coronaries. Immunocytochemistry demonstrated androgen receptors (AR) and P receptors in aorta and coronary arteries, and immunocytochemistry and Western blotting showed AR and P receptors in rhesus coronary vascular muscle cells. In vivo, MPA or DHT increased thromboxane prostanoid (TP) receptor expression in the aorta. In vitro, MPA or DHT increased, whereas P did not change, TP receptor expression in primary coronary vascular muscle cell. This MPA- or DHT-mediated increase in TP receptor expression was attenuated by the AR antagonist flutamide. MPA or DHT induction of CH in intact adult male primates, hypothesized to occur via androgenic up-regulation of vascular muscle TP receptor expression, could predispose to CH-mediated myocardial ischemia.

The effects of 17β-oestradiol plus dydrogesterone compared with conjugated equine oestrogens plus medroxyprogesterone acetate on lipids, apolipoproteins and lipoprotein(a)

OBJECTIVE

To compare the effects of 17 beta-oestradiol plus dydrogesterone with conjugated equine oestrogens plus medroxyprogesterone acetate on serum lipids, apolipoproteins and lipoprotein(a) in postmenopausal women.

METHODS

A multi-centre, prospective, randomised, double-blind, comparative one-year study in 362 healthy postmenopausal women aged 39-74 years with an intact uterus. Fasting blood samples were taken at baseline and after 28 and 52 weeks of treatment. Participants received daily oral treatment with continuous combined 1 mg micronised 17 beta-oestradiol/5 mg dydrogesterone (E/D: n=180) or 0.625 mg conjugated equine oestrogens/5 mg medroxyprogesterone acetate (CEE/MPA: n=182).

RESULTS

Significant differences between the two groups after 52 weeks were observed for total cholesterol (E/D: -1.7%; CEE/MPA: -7.3%), LDL-cholesterol (E/D: -4.5%; CEE/MPA: -11.3%), HDL-cholesterol (E/D: +15.3%; CEE/MPA: +7.5%), triglycerides (E/D: +9.8%; CEE/MPA: +16.6%), VLDL-triglycerides (E/D: -3.3%; CEE/MPA: +10.0%), lipoprotein(a) (E/D: 0.0%; CEE/MPA: -25.2%) and for the ratio apolipoprotein B/LDL-cholesterol (E/D: +0.9%; CEE/MPA +5.9%).

CONCLUSIONS

E/D and CEE/MPA differ in their anti-atherogenic effects on lipids and lipoproteins. This however can not easily be translated to differences in clinical cardiovascular outcomes.

Postmenopausal hormone therapy before and after the women's health initiative study: what consequences?

This review focuses on the question of whether the Women's Health Initiative (WHI) was a test of primary versus secondary cardiovascular benefits of postmenopausal hormone therapy. Evidence is presented to support the conclusion that the WHI was a secondary intervention trial and that primary cardiovascular benefits of hormone therapy are rational, likely, but not yet proven. The review makes clear that hormone therapy is not a 'cardiovascular drug' for the treatment of coronary heart disease; but rather that the public health debate is whether hormone therapy, used for the treatment of menopausal symptoms, provides any cardiovascular benefits that might offset its risk.