The acute effects of sublingual estradiol on left ventricular diastolic function in normotensive and hypertensive postmenopausal women

Acute ascorbic acid infusion increases left ventricular diastolic function in postmenopausal women

OBJECTIVES

We tested the hypothesis that oxidative stress contributes to reductions in left ventricular diastolic (LV) function in estrogen-deficient postmenopausal women, related in part to reduced nitric oxide (NO) bioavailability.

STUDY DESIGN

LV diastolic function - recorded using transthoracic echocardiography and determined as the peak early (E) to late (A) mitral inflow velocity ratio and the E to peak early (e') mitral annular velocity ratio - and brachial artery flow mediated dilation (FMD), a biomarker of NO bioavailability, were measured during acute systemic infusions of saline (control) and ascorbic acid (experimental model to decrease oxidative stress) in healthy premenopausal women (N=14, 18-40 years) and postmenopausal women (N=23, 45-75 years).

RESULTS

The E/A ratio was lower (1.16[1.06-1.33] vs 1.65[1.5-2.3]; median[interquartile range]) and the E/e' ratio was elevated (8.8[7.6-9.9] vs. 6.6[5.5-7.3]) in postmenopausal compared with premenopausal women, indicating reduced LV diastolic function. E/A and E/e' were correlated with FMD (r=0.54 and r=-0.59, respectively, both P<0.01). Ascorbic acid infusion improved both FMD (5.4±2.0% to 7.8±2.6%) and E/e' (to 8.1[7.2-9.7], P=0.01) in postmenopausal women but not in premenopausal women. Ascorbic acid did not change E/A in either group.

CONCLUSION

The current study provides evidence that oxidative stress contributes to reduced LV diastolic function in estrogen-deficient postmenopausal women, possibly by reducing the availability of NO.

Effects of estrogen on cardiovascular injury in ovariectomized female DahlS.Z-Lepr(fa)/Lepr(fa) rats as a new animal model of metabolic syndrome

Although recent clinical trials have found an increased incidence of cardiovascular disease in women on estrogen replacement therapy, the underlying mechanism remains unclear. We have recently characterized DahlS.Z-Lepr(fa)/Lepr(fa) (DS/obese) rats, derived from a cross between Dahl salt-sensitive and Zucker rats, as a new animal model of metabolic syndrome. We have now examined the effects of estrogen replacement on cardiac pathophysiology in ovariectomized female DS/obese (Ovx-DS/obese) rats. Animals subjected to ovariectomy at 7 weeks of age were implanted subcutaneously with a 60-day release pellet containing 0.5 mg of 17β-estradiol (E(2)) or placebo at 8 weeks. Age-matched female homozygous lean littermates (DahlS.Z-Lepr(+)/Lepr(+) or DS/lean rats) of DS/obese rats served as controls. Animals were maintained on a normal diet and were subjected to echocardiography followed by various pathological analyses at 13 weeks of age. Ovx-DS/obese rats manifested hypertension at 7 weeks of age and thereafter and showed left ventricular (LV) fibrosis and diastolic dysfunction at 13 weeks. Treatment with E(2) attenuated hypertension in Ovx-DS/obese rats but had no effect on blood pressure in ovariectomized female DS/lean (Ovx-DS/lean) rats. E(2) treatment exacerbated LV fibrosis and diastolic dysfunction, as well as further increased cardiac oxidative stress and inflammation in Ovx-DS/obese rats, and it elicited similar effects in Ovx-DS/lean rats. E(2) reduced food intake, body weight, and visceral fat content in both Ovx-DS/obese and Ovx-DS/lean rats. E(2) treatment attenuated hypertension and obesity but exacerbated LV fibrosis and diastolic dysfunction in Ovx-DS/obese rats, with these latter effects being associated with increased cardiac oxidative stress and inflammation.

Novel strategies and targets for the management of hypertension

Hypertension, as the sole or comorbid component of a constellation of disorders of the cardiovascular (CV) system, is present in over 90% of all patients with CV disease and affects nearly 74 million individuals in the United States. The number of medications available to treat hypertension has dramatically increased during the past 3 decades to some 50 medications as new targets involved in the normal regulation of blood pressure have been identified, resulting in the development of new agents in those classes with improved therapeutic profiles (e.g., renin-angiotensin-aldosterone system; RAAS). Despite these new agents, hypertension is not adequately managed in approximately 30% of patients, who are compliant with prescriptive therapeutics, suggesting that new agents and/or strategies to manage hypertension are still needed. Some of the newest classes of agents have targeted other components of the RAS, for example, the selective renin inhibitors, but recent advances in vascular biology have provided novel potential targets that may provide avenues for new agent development. These newer targets include downstream signaling participants in pathways involved in contraction, growth, hypertrophy, and relaxation. However, perhaps the most unique approach to the management of hypertension is a shift in strategy of using existing agents with respect to the time of day at which the agent is taken. This new strategy, termed "chronotherapy," has shown considerable promise in effectively managing hypertensive patients. Therefore, there remains great potential for future development of safe and effective agents and strategies to manage a disorder of the CV system of epidemic proportion.

Effect of hormone therapy on BP in normotensive and hypertensive postmenopausal women

High blood pressure (BP) ranks as the greatest risk factor for cardiovascular disease. The increased cardiovascular risk determined in recent interventional studies has led the health authorities in some countries to re-ignite the discussion about whether hypertension should be listed as a contraindication for hormone replacement therapy (HRT). We reviewed papers published since 1960 and listed in MEDLINE, EMBASE and Biosis, on studies that monitored the course of BP during HRT. We found that both primarily normotensive and hypertensive postmenopausal women actually run only a very low risk of BP increase during HRT, indeed, BP was often lowered. In one of our own studies 1397 hypertensive women with BP diastolic >95 mmHg received transdermal HRT regimens; BP was lowered by an average of 7 mmHg systolic and 9 mmHg diastolic. The results of the more recent 24-h ambulatory BP studies are particularly conclusive. At least 19 such studies have been performed, 13 placebo-controlled and 10 cross-over; 5 found no effect on BP and 14 studies demonstrated BP reductions. BP was lowered by treatment with transdermal estradiol in 11 of 13 studies and by oral estrogen in 4 of 11 studies. The effects were not consistent with regard to systolic or diastolic BP nor to action on day- and night-time BP. It cannot be ruled out that some women with a particular predisposition exhibit an abnormal reaction to the vasoactive effects of HRT, and there is a paucity of long-term data on risk populations, specifically on the progestogenic effects in patients with pre-existing arteriosclerotic lesions. In conclusion, the risk of developing hypertension during HRT is very low, but hormone therapy should always be appropriately indicated and during therapy BP should be checked regularly.

Effects of estradiol on myocardial global performance index in hypertensive postmenopausal women

The objective of this study was to assess the acute and chronic effects of estradiol on the myocardial performance index (MPI) in hypertensive postmenopausal women. There are conflicting reports on the effects of estrogen on left ventricular function in postmenopausal women, and we are unaware of any study on the myocardial performance index in the postmenopausal state. We undertook a prospective, randomized, double-blind, placebo-controlled study in 34 women, distributed into an estradiol group or a placebo group. After 90 min and at 12 weeks of administration of 1 mg of oral estradiol we evaluated, by Doppler echocardiography, its effects on the MPI. The estradiol group showed no alteration in the MPI after 90 min of the administration of estradiol. On the other hand, after 12 weeks of treatment we observed a statistically significant decrease of isovolumic relaxation time, from 127+/-23 ms to 106+/-16 ms (p < 0.001 and of the MPI from 0.63+/-0.13 to 0.48+/-0.09 (p < 0.01) and an increase in ejection time, from 297+/-32 ms to 330+/-31 ms (p < 0.01). In conclusion, estrogen replacement therapy over a period of 12 weeks showed a significant improvement in the MPI in hypertensive postmenopausal women, whereas the acute administration did not have any effect.

Effect of postmenopausal hormone replacement therapy on cardiovascular performance

Postmenopausal hormone replacement therapy (HRT) has usually been evaluated the relationship with atherosclerotic disease, whereas its effect on direct cardiac functions hasn't been investigated in detail. This study was planned to investigate the long-term effects of HRT on cardiac functions and exercise performance.

METHODS

Thirty-six postmenopausal women (mean age: 51 +/- 4 years, 39-60 years) were prospectively analyzed with pulsed wave Doppler echocardiography and symptom-limited exercise stress test before HRT (oral 0.625 mg conjugated estrogen and 2.5 mg medroxyprogesteron acetate/day), and at the third and the sixth months. The effect of HRT on left ventricular ejection fraction (EF), early filling velocity (E wave) and late filling velocity (A wave), E wave deceleration time (EDT), E/A ratio, myocardial performance index (MPI), exercise duration and METS changes were examined.

RESULTS

HRT did not significantly alter the left ventricular EF. At the third month of HRT, there was an insignificant increase in E wave, EDT, and E/A ratio, whereas an insignificant decrease was noted in MPI (P > 0.05). However, at the sixth month of HRT, these changes became significant (68 +/- 12 vs. 75 +/- 13 cm/s, P < 0.01; 171 +/- 24 vs. 184 +/- 14 ms, P < 0.01; 1.01 +/- 0.23 vs. 1.11 +/- 0.27, P < 0.01, and 44 +/- 9 vs. 39 +/- 8%, P < 0.001, respectively). On the other hand, exercise duration and exercise METS values showed significant improvements at the third month of HRT (423 +/- 104 vs. 482 +/- 104 s, P < 0.001; 8.2 +/- 1.7 vs. 9.1 +/- 2 METS, P < 0.001). These improvements also continued at the sixth month of HRT. In conclusion, postmenopausal HRT leads to a progressive improvement on left ventricular function parameters, and in parallel, in exercise performance.

Left ventricular diastolic function assessment by tissue Doppler echocardiography in relation to hormonal replacement therapy in postmenopausal women with diastolic dysfunction

The objective of this study was to evaluate the effect of hormone replacement therapy (HRT) regimens on left ventricular diastolic function by using mitral pulsed wave Doppler (MPWD) and tissue Doppler velocities (TDE). Seventy-eight postmenopausal women with normotensive and impaired diastolic left ventricular filling were included in the study. All the patients began a six-cycle HRT course. This formulation consisted of E2 valerate plus Medroxy progesterone acetate (MPA). Left ventricular diastolic function at rest was evaluated by M-mode, two-dimensional, MPWD and TDE in 78 postmenopausal women with normal blood pressure before the treatment for 6 months of HRT. The M-mode, two-dimensional, and MPWD parameters assessed were heart rate, systolic blood pressure, diastolic blood pressure, left ventricular mass index, ejection fraction of the left ventricle (EF), septal (IVS) and posterior wall (PW) thickness, left ventricular end-systolic (LVESD) and end-diastolic (LVEDD) diameter, left atrial diameter, peak early diastolic velocity (E), peak atrial velocity (A), E/A ratio, E acceleration time, E deceleration time, diastolic filling period, and isovolumic relaxation time (IVRT). The TDE parameters assessed were peak early diastolic velocity (E'), peak late diastolic velocity (A'), peak systolic velocity, E'/A' ratio, E' acceleration time, E' deceleration time, IVRT', and E/E' ratio. Quantitative data were analyzed using Student t test. Among the MPWD parameters, peak A velocity, E deceleration time, and IVRT significantly decreased, while peak E velocity and E/A ratio increased after a 6-month treatment. From the point of TDE parameters, E' velocity and E'/A' ratio increased, while A' velocity, E' deceleration time, E/E' ratio and IVRT' decreased. Some MPWD and TDE parameters were partially reversed after HRT. TDE velocities and especially E/E' ratio may provide better and true information of the diastolic function. TDE parameters were independent from the preload and did not produce pseudonormal pattern. HRT may cause increase in the blood volume and produce pseudonormal pattern in transmitral flow. In that case, TDE may be a beneficial method for evaluation of diastolic function.

Systemic hypertension in postmenopausal women: a clinical approach

Gender-specific differences in the incidence of cardiovascular disease have long been known, and estrogens have been considered to be responsible for this dissimilarity. Recently, the steep increase in cardiovascular risk in the no longer fertile woman has become evident. The postmenopausal metabolic syndrome is very frequent, with obesity, insulin resistance, and hyperinsulinemia, which convey increased sodium reabsorption, stimulation of the sympathetic nervous system, and smooth muscle growth. The clinical corollary of these overall changes is hypertension. Gender differences in components of the renin-angiotensin system have been shown to exist, and may play a central role in blood pressure control. In normotensive populations, plasma renin activity is significantly higher in men than in women, and is higher in postmenopausal versus premenopausal women. Two angiotensin-converting enzyme inhibitors, ramipril and moexipril, have undergone trials aimed specifically at older people with cardiovascular risk and with postmenopausal hypertension, and could be the first therapeutic choice. However, a comprehensive treatment should include nonpharmacologic measures with strong emphasis on weight normalization and regular physical activity, prevention of osteoporosis, as well as decisions on the use of estrogen replacement therapy and treatment of the menopausal metabolic syndrome. Finally, education of both patients and physicians on the nature and prognosis of untreated hypertension is crucial.

Resistive index of renal artery and blood pressure in postmenopausal women

Causal association between perimenopausal changes and symptoms and disease is commonly accepted even if not definitely explained. Resistive index (RI) of renal artery assessed by Doppler echography is related to renal function and systemic circulatory adaptation in patients with chronic renal failure and hypertension. Echocardiographic measurement of left ventricular myocardial mass (LVMM) is a useful tool for assessing effects of arterial hypertension on heart. Aim of the study was to assess RI in normotensive postmenopausal women and relationship, if any, with blood pressure and LVMM. We studied 28 normotensive, non-obese postmenopausal women, age 52.21 +/- 5.40 years, with normal creatinine clearance. Renal colour-Doppler echography was performed assessing intra-parenchimal renal artery mean velocity (mVRA) and intra-parenchimal RI [(peak systolic velocity - end diastolic velocity)/peak systolic velocity]. Echocardiography was performed as well. RI of intra-parenchimal renal artery is 0.67 +/- 0.05 and it shows correlations vs. diastolic blood pressure (r=0.41; P<0.03) and vs. mean BP (r=0.47; P<0.01). LVMM has correlation (r=0.41; P>0.03) with RI. Age, body weight, body mass index, menarche age, fertility years and postmenopausal years do not show correlation with RI. Heart rate, creatinine clearance, hemoglobin, serum albumin do not show any correlation with RI. Higher RI is associated with alcohol intake, liver steatosis, biliary gallstones and family history of diabetes mellitus, but not with postmenopausal years, unrespective of surgical or non-surgical menopause. Among echocardiographic measurements only LVMM is correlated with RI; mVRA does not show correlation. LVMM and BP do not show other independent correlation except that the one already reported vs. RI. RI, as a pathophysiological measurement whose increase preludes to arterial hypertension, could help to ascertain perimenopausal women at risk for arterial hypertension and left ventricular hypertrophy, but does not seem directly associated with the loss of ovarian function.

Hypertension in menopausal women--a special case, for special treatment?

After the menopause the consequences of hypertension in women change. Their risks of myocardial infarction and stroke rise steeply, a rise that has been blamed in part on the loss of estrogen and the onset of menopausal metabolic syndrome, with endothelial dysfunction, hyperlipidemia, insulin resistance and derangement in coagulation. Hypertensive menopausal women have not had optimum treatment. They have poorer prognoses than men of the same age. Their antihypertensive management therefore merits special attention. Hormone replacement, aspirin prophylaxis and lipid-lowering drugs have their place. The antihypertensive drug chosen should not worsen the metabolic syndrome: angiotensin-II converting enzyme (ACE) inhibitors are therefore among the first-line drugs. Few drugs have been specifically aimed at menopausal hypertension and these are reviewed here.