Low-dose spironolactone in the management of resistant hypertension: a surveillance study

Assessment of ursolic acid effect on in vitro model of cardiac fibrosis

This study aimed to evaluate the effects of ursolic acid (UA) on Angiotensin II (Ang II)-treated neonatal rat cardiac fibroblasts (rCFs) as an in vitro model of cardiac fibrosis. The rCFs were isolated from two-day-old neonatal rats. An in vitro model of cardiac fibrosis was established using 500 nm Ang II treatment for 48 h. The cells were then treated with 5 and 10 μM of UA for 24 and 48 h. Masson's trichrome staining, hydroxyproline content assay, scratch assay, apoptosis assay, measurements of superoxide dismutase (SOD) and malondialdehyde (MDA) levels, real-time PCR, immunocytology and western blotting, were employed to assess the impact of UA. Ang II induced fibrosis in rCFs, as evidenced by the examination of various fibrotic markers. Upon treatment with 5 and 10 μM of UA, the amount of fibrosis in Ang II-treated rCFs was significantly decreased, so that the hydroxyproline concentration was reduced to 0.3 and 0.7 times, respectively. The RNA expression of the Col1a1, Col3a1, Tgfb1, Acta2 and Mmp2 genes had a decrease as well as Nrf2 and HO-1 had an increase after UA treatment. UA could lessen the harmful effects of cardiac fibrosis in a dose- and time-dependent manner, due to its antiapoptotic, antioxidant and cardioprotective properties. This suggests the potential of UA for treatment of cardiac fibrosis.

Resistant hypertension: Diagnosis, evaluation, and treatment practical approach

The term RH describes a subgroup of hypertensive patients whose BP is uncontrolled despite the use of at least three antihypertensive drugs in an appropriate combination at optimal or best tolerated doses. True RH is considered when appropriate lifestyle measures and treatment with optimal or best tolerated doses of three or more drugs (a thiazide/thiazide-like diuretic, plus renin-angiotensin system -RAS- blocker and a calcium channel blocker -CCB-) fail to lower office BP to <140/90 mmHg; besides the inadequate BP control should be confirmed by home blood pressure monitoring (HBPM) or 24-hour ambulatory; and evidence of adherence to therapy and exclusion of secondary causes of hypertension are required. RH patients are at a high risk of cardiovascular events and death. RH is associated with a higher prevalence of end-organ damage. When stricter criteria are applied, a reasonable estimate of the prevalence of true RH is 5 % of the total hypertensive population. The predominant hemodynamic pattern appears to be increased systemic vascular resistance and plasma volume with normal or even low cardiac output. We must rule out pseudo-resistance before diagnosing true drug resistance. RH is a therapeutic challenge, and its management includes lifestyle interventions, avoiding nonadherence to treatment, avoiding inertia, appropriate use of antihypertensive drugs based on current evidence, especially long-acting diuretics, and the addition of mineralocorticoid receptor antagonists. RCTs to identify the most protective medical therapy in RH are needed. A series of drugs in different stages of investigation could significantly impact RH treatment in the future.

[Expert opinion. Spironolactone: a new twist on an old story]

The article presents recent data on possibilities of a broader use of mineralocorticoid receptor antagonists for existing indications and of expanding indications for the use of this pharmaceutical group in the context of the novel coronavirus infection COVID-19. The authors discussed prospects for expanded detection of aldosteronism using a new diagnostic approach, including an additional evaluation of blood pressure response to spironolactone.

Managing resistant hypertension: focus on mineralocorticoid-receptor antagonists

Mineralocorticoid-receptor antagonists (MRAs) have proven to be effective in some types of hypertension, especially in resistant hypertension (RHTN). In this phenotype of hypertension, the renin-angiotensin-aldosterone pathway plays an important role, with MRAs being especially effective in reducing blood pressure. In this review, we show the relevance of aldosterone in RHTN, as well as some clinical characteristics of this condition and the main concepts involving its pathophysiology and cardiovascular damage. We analyzed the mechanisms of action and clinical effects of two current MRAs - spironolactone and eplerenone - both of which are useful in RHTN, with special attention to the former. RHTN represents a significant minority (10%-15%) of hypertension cases. However, primary-care physicians, cardiologists, nephrologists, neurologists, and geriatricians face this health problem on a daily basis. MRAs are likely one of the best pharmacological options in RHTN patients; however, they are still underused.

Signal Enhancement in the HPLC-ESI-MS/MS analysis of spironolactone and its metabolites using HFIP and NH4F as eluent additives

This paper describes an LC-MS/MS method to determine the concentration of spironolactone and its metabolites 7-alpha-methylthiospironolactone and canrenone in blood plasma samples. The resulting assay is simple (using protein precipitation for sample preparation) and sensitive (the lower limit of quantification is close to 0.5 ng/ml) while requiring only 50 μl of plasma, making it especially suitable for analyzing samples obtained from pediatric and neonatal patients where sample sizes are limited. The sensitivity is achieved by using ammonium fluoride as an eluent additive, which in our case amplifies the signal from our analytes in the plasma solution on average about 70 times. The method is fully validated according to the European Medicines Agency's guideline and used for the measurement of pediatric patients' samples in clinical trials for evaluating oral spironolactone's and its metabolites' pharmacokinetics in children up to 2 years of age.

A meta-analysis of add-on use of spironolactone in patients with resistant hypertension

OBJECTIVE

The efficacy of add-on use of spironolactone in patients with resistant hypertension has been investigated in several small studies. We performed this meta-analysis evaluating the efficacy of add-on use of spironolactone in these patients.

METHODS

We searched Pubmed, Web of Science, and Cochrane Central for all published studies evaluating add-on use of spironolactone in patients with resistant hypertension. Only randomized controlled trials determining antihypertensive effects of spironolactone were considered.

RESULTS

The antihypertensive effects were assessed in 869 patients included in 4 trials with a mean follow-up of 12±3weeks. The reduction of systolic blood pressure (SBP) and diastolic BP (DBP) in patients treated with spironolactone was greater than placebo (weighted mean differences (WMD) for SBP -16.67mmHg (95% confidence interval (CI), -27.54, -5.80), p<0.01; WMD for DBP -6.11mmHg (95% CI, -9.34, -2.88), p<0.001), respectively. The rates of serious adverse effects or patient withdrawals from the trials tended to be higher in patients treated with spironolactone than placebo (WMD for odds ratio 2.11 (95% CI, 0.98, 4.53), p=0.05).

CONCLUSIONS

This meta-analysis provides the evidence that add-on use of spironolactone in patients with resistant hypertension is effective in lowering SBP and DBP, suggesting an add-on use of spironolactone as fourth line therapy in patients with resistant hypertension.

New Evidence Supporting the Use of Mineralocorticoid Receptor Blockers in Drug-Resistant Hypertension

Treatment resistant hypertension (TRH), defined as a blood pressure above goal despite treatment with optimally tolerated doses of 3 antihypertensive agents of different classes, ideally including a diuretic, remains a significant problem and its management an area of uncertainty for physicians. One hypothesis is that resistant hypertension is due to abnormal sodium retention, mediated by aldosterone breakthrough occurring despite blockade of the renin-angiotensin-aldosterone system with angiotensin converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB). Thus, there has been renewed interest in the use of mineralocorticoid receptor blockers (MRB) to treat this condition. This article critically evaluates new evidence supporting the use of MRB in TRH published in the last 3 years. We conclude that there is now sufficient evidence to recommend MRB, in particular spironolactone, as the first choice medication to treat this condition, and for its inclusion in future guidelines.

Diuretics in the treatment of hypertension

Diuretics have long been used for the treatment of hypertension. Thiazide diuretics are the most commonly prescribed diuretics for hypertension, but other classes of diuretics may be useful in alternative circumstances. Although diuretics are no longer considered the preferred agent for treatment of hypertension in adults and children, they remain acceptable first-line options. Diuretics effectively decrease blood pressure in hypertensive patients, and in adults with hypertension reduce the risk of adverse cardiovascular outcomes. Because of varied pharmacokinetic and pharmacodynamic differences, chlorthalidone may be the preferred thiazide diuretic in the treatment of primary hypertension. Other types of diuretics (e.g., loop, potassium sparing) may be useful for the treatment of hypertension related to chronic kidney disease (CKD) and other varied conditions. Common side effects of thiazides are mostly dose-related and involve electrolyte and metabolic abnormalities.

Low-dose Spironolactone: Treatment for Osteoarthritis-related Knee Effusion. A Prospective Clinical and Sonographic-based Study

OBJECTIVE

To evaluate the effectiveness of spironolactone as a treatment for osteoarthritis (OA)-related knee effusion in comparison to ibuprofen, cold compresses, and placebo.

METHODS

This study was carried out on 200 patients, aged 40 years or older, attending the outpatient clinic of the Rheumatology Department of Sohag University Hospital with unilateral knee effusion related to OA based on clinical examination, musculoskeletal ultrasonography (US), and synovial fluid analysis. In group 1, 50 patients received spironolactone 25 mg daily for 2 weeks; in group 2, 50 patients took ibuprofen 1200 mg daily for 2 weeks; in group 3, 50 patients used cold compresses 2 times daily for 2 weeks; and in group 4, 50 patients received placebo for the same duration. Fluid > 4 mm was considered as effusion. Decrease in fluid to reach below 4-mm thickness was considered complete improvement, and any decrease that did not reach below 4 mm thickness was considered partial improvement.

RESULTS

The mean age of the participants was 51.2 ± 8.1 years. The mean duration of effusion was 16.5 ± 3.6 days. In group 1, 66% had complete improvement, 20% partial improvement, and 14% no response. In group 2, 24% had complete improvement, 12% partial improvement, and 64% no response. In group 3, 28% had complete improvement, 14% partial improvement, and 58% no response. In group 4, only 6% had complete improvement, 10% partial improvement, and 84% no response.

CONCLUSION

Low-dose spironolactone is a safe and effective medical treatment for OA-related knee effusion.

Clinical Diagnosis and Management of Resistant Hypertension

Resistant hypertension (RHT) is variably defined as insufficient blood pressure (BP) response to multiple drug treatment. Prevalence of RHT has been thoroughly studied in the recent years, ranging from about 5 to 30 % in various cohorts. Initial management of patients with apparent RHT requires identification of true treatment resistance by out-of-office BP measurements, assessment of adherence and screening for treatable causes of uncontrolled BP. Endorsement of lifestyle modifications and maximisation of the doses of a suitable regimen, preferably with the further addition of an aldosterone antagonist, are the mainstay of treatment. An invasive approach to RHT, mainly represented by renal nerve ablation, should be kept for persistently severe cases managed in a specialised hypertension centre.

The Effects of Aldosterone Antagonists in Patients With Resistant Hypertension: A Meta-Analysis of Randomized and Nonrandomized Studies

BACKGROUND

A few studies have shown aldosterone antagonists (AA) to be effective therapy in patients with resistant hypertension (RH). We performed a meta-analysis of randomized and nonrandomized studies of AA in patients with RH.

METHODS

We searched PUBMED, EMBASE, and CENTRAL for studies on the use of AA in patients with RH. Meta-analysis was performed using random-effects model. The change in office and ambulatory blood pressures (BP), effects on biochemical profile, change in the number of antihypertensive agents, and adverse events were main outcomes.

RESULTS

We included 15 studies (3 randomized controlled trials, 1 nonrandomized comparative study, and 11 single-arm studies) with 1,204 total patients in the meta-analysis. In comparative studies, AA reduced systolic BP (SBP) by 24.26 mm Hg (95% CI: 8.65-39.87, P = 0.002) and diastolic BP (DBP) by 7.79 mm Hg (3.79-11.79, P = 0.0001). Similarly, AA reduced SBP by 22.74 mm Hg (18.21-27.27, P < 0.00001) and DBP by 10.49 mm Hg (8.85-12.13, P < 0.00001) in single-arm studies. AA resulted in significant change in serum electrolytes in single-arm studies but not in comparative studies. Significantly more adverse events were noted in single-arm studies but not in comparative studies.

CONCLUSIONS

On the basis of the current meta-analysis, we conclude that AA is safe and effective therapy in patients with RH.

Amiloride lowers blood pressure and attenuates urine plasminogen activation in patients with treatment-resistant hypertension

In conditions with albuminuria, plasminogen is aberrantly filtered across the glomerular barrier and activated along the tubular system to plasmin. In the collecting duct, plasmin activates epithelial sodium channels (ENaC) proteolytically. Hyperactivity of ENaC could link microalbuminuria/proteinuria to resistant hypertension. Amiloride, an ENaC inhibitor, inhibits urokinase-type plasminogen activator. We hypothesized that amiloride (1) reduces blood pressure (BP); (2) attenuates plasminogen-to-plasmin activation; and (3) inhibits urine urokinase-type plasminogen activator in patients with resistant hypertension and type 2 diabetes mellitus (T2DM).In an open-label, non-randomized, 8-week intervention study, a cohort (n = 80) of patients with resistant hypertension and T2DM were included. Amiloride (5 mg/d) was added to previous triple antihypertensive treatment (including a diuretic and an inhibitor of the renin-angiotensin-aldosterone system) and increased to 10 mg if BP control was not achieved at 4 weeks. Complete dataset for urine analysis was available in 60 patients. Systolic and diastolic BP measured by ambulatory BP monitoring and office monitoring were significantly reduced. Average daytime BP was reduced by 6.3/3.0 mm Hg. Seven of 80 cases (9%) discontinued amiloride due to hyperkalemia >5.5 mol/L, the most frequent adverse event. Urinary plasmin(ogen) and albumin excretions were significantly reduced after amiloride treatment (P < .0001). Urokinase activity was detectable in macroalbuminuric urine, with a tendency toward reduction in activity after amiloride treatment. Amiloride lowers BP, urine plasminogen excretion and activation, and albumin/creatinine ratio, and is a relevant add-on medication for the treatment of resistant hypertension in patients with T2DM and microalbuminuria.

Prevention And Treatment of Hypertension With Algorithm-based therapy (PATHWAY) number 2: protocol for a randomised crossover trial to determine optimal treatment for drug-resistant hypertension

INTRODUCTION

Resistant hypertension is inadequately controlled blood pressure (BP) despite treatment with at least three BP-lowering drugs. A popular hypothesis is that resistant hypertension is due to excessive Na(+)-retention, and that 'further diuretic therapy' will be superior to alternative add-on drugs.

METHODS AND ANALYSIS

Placebo-controlled, random crossover study of fourth-line treatment when added to standard (A+C+D) triple drug therapy: ACE inhibitor or Angiotensin receptor blocker (A) +Calcium channel blocker (C)+Diuretic (D). Patients (aged 18-79 years) with clinical systolic BP ≥ 140 mm Hg (135 mm Hg in diabetics) and Home BP Monitoring (HBPM) systolic BP average ≥ 130 mm Hg on treatment for at least 3 months with maximum tolerated doses of A+C+D are randomised to four consecutive randomly allocated 12-week treatment cycles with an α-blocker, β-blocker, spironolactone and placebo. The hierarchical coprimary end point is the difference in HBPM average systolic BP between (in order) spironolactone and placebo, spironolactone and the average of the other two active drugs, spironolactone and each of the other two drugs. A key secondary outcome is to determine whether plasma renin predicts the BP response to the different drugs. A sample size of 346 (allowing 15% dropouts) will confer 90% power to detect a 3 mm Hg HBPM average systolic BP difference between any two drugs. The study can also detect a 6 mm Hg difference in HBPM average systolic BP between each patient's best and second-best drug predicted by tertile of plasma renin.

ETHICS AND DISSEMINATION

The study was initiated in May 2009 and results are expected in 2015. These will provide RCT evidence to support future guideline recommendations for optimal drug treatment of resistant hypertension.

TRIAL REGISTRATION NUMBER

Clinicaltrials.gov NCT02369081, EUDract number: 2008-007149-30.

Drug therapy of apparent treatment-resistant hypertension: focus on mineralocorticoid receptor antagonists

Apparent treatment-resistant hypertension (aTRH) is defined as blood pressure (BP) >140/90 mmHg despite three different antihypertensive drugs including a diuretic. aTRH is associated with an increased risk of cardiovascular events, including stroke, chronic renal failure, myocardial infarction, congestive heart failure, aortic aneurysm, atrial fibrillation, and sudden death. Preliminary studies of renal nerve ablation as a therapy to control aTRH were encouraging. However, these results were not confirmed by the Symplicity 3 trial. Therefore, attention has refocused on drug therapy. Secondary forms of hypertension and associated conditions such as obesity, sleep apnea, and primary aldosteronism are common in patients with aTRH. The pivotal role of aldosterone in the pathogenesis of aTRH in many cases is well recognized. For patients with aTRH, the Joint National Committee-8, the European Society of Hypertension, and a recent consensus conference recommend that a diuretic, ACE inhibitor, or angiotensin receptor blocker and calcium channel blocker combination be used to maximally tolerated doses before starting a 'fourth-line' drug such as a mineralocorticoid receptor (MR) antagonist. Although the best fourth-line drug for aTRH has not been extensively investigated, a number of studies summarized here show that an MR antagonist is effective in reducing BP when added to the standard multi-drug regimen.

New developments in the pharmacological treatment of hypertension: dead-end or a glimmer at the horizon?

Arterial hypertension is the most prevalent controllable disease world-wide. Yet, we still need to further improve blood pressure control, deal with resistant hypertension, and we hope to reduce risk "beyond blood pressure." The number of candidate molecules aspiring for these aims is constantly declining. The new possible approaches to combat high blood pressure include neprilysin/neutral endopeptidase (NEP) inhibition, particularly when combined with an angiotensin receptor blockade (such as the ARNI, LCZ696), phosphodiesterase 5 (PDE5) inhibition (KD027/Slx-2101), natriuretic agents (PL3994), or a long-lasting vasointestinal peptide (VIP) analogue (PB1046). Other options exploit the protective arm of the renin-angiotensin-aldosterone system by stimulating the angiotensin AT2 receptor (compound 21), the Mas receptor (AVE-0991), or the angiotensin converting enzyme 2. Finally, we review the possibilities how to optimize the use of the available treatment options by using drug combinations or by tailoring therapy to each patient's angiotensin peptide profile.

[Antihypertensive drug therapy : Where do we stand?]

Antihypertensive drug therapy is one of the most successful medical measures ever, at all levels. The treatment situation in Germany has clearly improved in recent years. Nowadays, a wide range of very effective and well-tolerated hypertensive substances is available. Combination therapy has a long and successful tradition in hypertensive treatment, especially with suitable fixed combinations. Furthermore, the administration of fixed combinations is very beneficial to therapy adherence because it is essentially dependent on the number of drugs to be taken. The value of beta blockers and the double blockade of the renin-angiotensin-aldosterone system are under discussion and the interpretation of corresponding studies must be conducted very carefully. The hypertensive effect of a substance cannot be comprehensively assessed without taking the time of day, the time point of measurement and the time point of intake into consideration. This is particularly important with respect to the effect over 24 h. Optimal antihypertensive therapy must also take into consideration the individual blood pressure rhythm with respect to the dose and dosing intervals. The importance of the central (aortic) blood pressure as target blood pressure will increase.

Mineralocorticoid Receptor Antagonists Therapy in Resistant Hypertension: Time to Implement Guidelines!

Despite the availability of anti-hypertensive medications with increasing efficacy up to 50% of hypertensive patients have blood pressure levels (BP) not at the goals set by international societies. Some of these patients are either not optimally treated or are non-adherent to the prescribed drugs. However, a proportion, despite adequate treatment, have resistant hypertension (RH), which represents an important problem in that it is associated to an excess risk of cardiovascular events. Notwithstanding a complex pathogenesis, an abundance of data suggests a key contribution for the mineralocorticoid receptor (MR) in RH, thus fostering a potential role for its antagonists in RH. Based on these premises randomized clinical trials aimed at testing the efficacy of MR antagonists (MRAs) in RH patients have been completed. Overall, they demonstrated the efficacy of MRAs in reducing BP and surrogate markers of target organ damage, such as microalbuminuria, either compared to placebo or to other drugs. In summary, owing to the key role of the MR in the pathogenesis of RH and on the proven efficacy of MRAs we advocate their inclusion as an essential component of therapy in patients with presumed RH. Conversely, we propose that RH should be diagnosed only in patients whose BP values show to be resistant to an up-titrated dose of these drugs.

Effect of spironolactone in resistant arterial hypertension: a randomized, double-blind, placebo-controlled trial (ASPIRANT-EXT)

This study was designed to assess the effect of the addition of low-dose spironolactone on blood pressure (BP) in patients with resistant arterial hypertension. Patients with office systolic blood pressure (SBP) >140 mm Hg or diastolic blood pressure (DBP) >90 mm Hg despite treatment with at least 3 antihypertensive drugs, including a diuretic, were enrolled in this double-blind, placebo-controlled, multicentre trial. One hundred sixty-one patients in outpatient internal medicine departments of 6 hospitals in the Czech Republic were randomly assigned to receive 25 mg of spironolactone (N = 81) or a placebo (N = 80) once daily as an add-on to their antihypertensive medication, using simple randomization. This study was registered with ClinicalTrials.gov, number NCT00524615. A nalyses were done with 150 patients who finished the follow-up (74 in the spironolactone and 76 in the placebo group). At 8 weeks, BP values were decreased more by spironolactone, with differences in mean fall of SBP of -9.8, -13.0, -10.5, and -9.9 mm Hg (P < 0.001 for all) in daytime, nighttime, and 24-hour ambulatory BP monitoring and in the office. The respective DBP differences were -3.2, -6.4, -3.5, and -3.0 mm Hg (P = 0.013, P < 0.001, P = 0.005, and P = 0.003). Adverse events in both groups were comparable. The office SBP goal <14 mm Hg at 8 weeks was reached in 73% of patients using spironolactone and 41% using placebo (P = 0.001). Spironolactone in patients with resistant arterial hypertension leads to a significant decrease of both SBP and DBP and markedly improves BP control.

Non-interventional management of resistant hypertension

Hypertension is one of the most popular fields of research in modern medicine due to its high prevalence and its major impact on cardiovascular risk and consequently on global health. Indeed, about one third of individuals worldwide has hypertension and is under increased long-term risk of myocardial infarction, stroke or cardiovascular death. On the other hand, resistant hypertension, the “uncontrollable” part of arterial hypertension despite appropriate therapy, comprises a much greater menace since long-standing, high levels of blood pressure along with concomitant debilitating entities such as chronic kidney disease and diabetes mellitus create a prominent high cardiovascular risk milieu. However, despite the alarming consequences, resistant hypertension and its effective management still have not received proper scientific attention. Aspects like the exact prevalence and prognosis are yet to be clarified. In an effort to manage patients with resistant hypertension appropriately, clinical doctors are still racking their brains in order to find the best therapeutic algorithm and surmount the substantial difficulties in controlling this clinical entity. This review aims to shed light on the effective management of resistant hypertension and provide practical recommendations for clinicians dealing with such patients.

Low dose spironolactone reduces blood pressure in patients with resistant hypertension and type 2 diabetes mellitus: a double blind randomized clinical trial

BACKGROUND

The increased risk of cardiovascular morbidity and mortality associated with arterial hypertension is particularly pronounced in patients with type 2 diabetes mellitus. Blood pressure control is, therefore, decisively important but often not sufficiently achieved.

OBJECTIVE

The primary objective of this study was to evaluate the antihypertensive effect of low dose spironolactone added to triple therapy for resistant hypertension in patients with type 2 diabetes measured by ambulatory monitoring. Secondary objectives were to evaluate the effects on glycaemic control and urinary albumin excretion as well as adverse effects.

METHODS

In a multicentre, double-blind, randomized, placebo-controlled study 119 patients with blood pressure at or above 130/80 mmHg despite triple antihypertensive therapy were included. One tablet of 25 mg spironolactone or placebo was added to previous treatment and increased to two if blood pressure below 130/80 mmHg was not achieved after 4 weeks. Blood pressure was measured by ambulatory monitoring at baseline and after 16 weeks.

RESULTS

The study was completed by 112 patients, 57 randomized to spironolactone and 55 to placebo. Average daytime placebo-corrected blood pressure was reduced by 8.9 (4.7-13.2)/3.7 (1.5-5.8) mmHg. Also office blood pressure, night-time, 24-h and pulse pressures were reduced significantly. Urinary albumin/creatinine ratio was significantly reduced in the spironolactone group. Glycaemic control remained unchanged. Hyperkalemia was the most frequent adverse event leading to dose reduction in three cases and discontinuation in one, whereas gynaecomastia was not reported.

CONCLUSION

Low dose spironolactone exerts significant BP and urinary albumin creatinine ratio lowering effects in high-risk patients with resistant hypertension and type 2 diabetes mellitus.

Aldosterone synthase inhibition in hypertension

Hypertension is an established risk factor for stroke, premature coronary artery disease and heart failure. Control of elevated blood pressure has been shown to result in significant reduction of cardiovascular risk. Aldosterone, the final product of the renin-angiotensin-aldosterone system (RAAS), not only causes salt and water reabsorbtion in the kidneys through its effect on the mineralocorticoid hormone receptor (MR), but also an MR-independent effect, not regulated by conventional MR blockade. Although many pharmacological agents target different levels of the RAAS cascade, these generally result in elevated renin concentration and plasma renin activity. This upstream feedback response subsequently results in elevated levels of angiotensin II, a potent vasoconstrictor and stimulus to aldosterone release. This aldosterone breakthrough counteracts the long-term blood pressure-lowering effect of these agents. Therefore the development of a new class of pharmacologic agents that directly inhibit the production of aldosterone may prove clinically useful in reducing aldosterone and thereby controlling elevated blood pressure.

Serum potassium levels predict blood pressure response to aldosterone antagonists in resistant hypertension

The objective of this study was to identify factors associated with the blood pressure (BP) response to spironolactone--aldosterone receptor antagonist as an add-on therapy in patients with resistant hypertension (HTN). We retrospectively reviewed the data of subjects with resistant HTN who were treated with add-on spironolactone in a large HTN clinic. A paired Student's t-test was used to assess the differences between the BP values before and during spironolactone administration, and multivariate analysis was used to assess the predictors of a satisfactory BP response (a decrease in systolic BP >10%). We analyzed the data of 48 hypertensive participants. The add-on spironolactone therapy had a significant BP-lowering effect in both systolic and diastolic BP values (P < 0.01 for both). Baseline serum potassium levels of <4.5 mEq l(-1) were associated with a satisfactory BP response (P < 0.01). Furthermore, every decrement of 1 mEq l(-1) of serum potassium was independently associated with a fivefold higher rate of achieving a satisfactory BP response to spironolactone therapy (P = 0.024). Additional factors independently associated with an improved systolic BP response were old age (P = 0.033), body mass index (P = 0.033) and high baseline systolic BP (P=0.004). Our results support the use of add-on spironolactone therapy in patients with resistant HTN who are elderly and obese and have high systolic BP and serum potassium levels <4.5 mEq l(-1).

Effectiveness of the direct renin inhibitor, aliskiren, in patients with resistant hypertension

Currently there is no consensus regarding which add-on therapy to use in resistant hypertension. We have conducted an open observational study of the use of aliskiren in resistant hypertensive patients. Forty-three patients with resistant hypertension were included in the study. The inclusion criteria were as follows: 1) office blood pressure (BP) > 140/90 mmHg despite treatment with at least three or more antihypertensive drugs; 2) no prior therapy with aliskiren; and 3) no renal insufficiency. Follow-up BP was determined at 1 and 3 months. Baseline BP was 153 ± 12/79 ± 12 mmHg. After 3 months, systolic BP (SBP) and diastolic BP (DBP) dropped significantly: 140 ± 19/73 ± 13 mmHg (P < 0.0001). Twenty-one patients (49%) had an office BP < 140/90 mmHg, and these patients were assigned to the good BP control group. Another 22 were placed into the poor BP control group. BP reductions from baseline in the good BP control group (SBP/ DBP: 19 ± 11/8 ± 7 mmHg) were larger than those in the poor BP control group (5 ± 15/3 ± 9 mmHg, P < 0.05). Mean BP (MBP) values at baseline, 1, and 3 months were higher in the poor BP control group. There was no significant difference in pulse pressure at baseline between the 2 groups. In multivariate analysis, only MBP at baseline correlated with lack of BP control. Aliskiren administration to resistant hypertensive patients was effective in reducing BP. The present findings suggest aliskiren may be useful as a fourth-line or fifth-line treatment added to other drugs in the treatment of resistant hypertension.

Spironolactone, eplerenone and the new aldosterone blockers in endocrine and primary hypertension

Mineralocorticoid receptor antagonists (MRAs) are commonly used to reduce blood pressure, left-ventricular hypertrophy, and urinary albumin excretion in patients with essential hypertension or primary aldosteronism. Effects of MRAs on hypertensive organ damage seem to occur beyond what is expected from the mere reduction of blood pressure. This suggests that activation of the mineralocorticoid receptor plays a central role in the development of cardiac and renal abnormalities in hypertensive patients. However, broad use of classic MRAs such as spironolactone has been limited by significant incidence of gynecomastia and other sex-related adverse effects. To overcome these problems, new aldosterone blockers have been developed with different strategies that include use of nonsteroidal MRAs and inhibition of aldosterone synthesis. Both strategies have been designed to avoid the steroid receptor cross-reactivity of classic MRAs that accounts for most adverse effects. Moreover, inhibition of aldosterone synthesis could have an additional benefit due to blockade of the mineralocorticoid receptor-independent pathways that might account for some of the untoward effects of aldosterone. The new aldosterone blockers are currently having extensive preclinical evaluation, and one of these compounds has passed phase 2 trials showing promising results in patients with primary hypertension and primary aldosteronism. This narrative review summarizes the knowledge on the use of classic MRAs in hypertension and covers the evidence currently available on new aldosterone blockers.

Determinants of blood pressure reduction by eplerenone in uncontrolled hypertension

BACKGROUND

Add-on therapy with aldosterone receptor antagonists has been reported to lower blood pressure (BP) in patients with uncontrolled hypertension. We assessed potential predictors of this response.

METHODS

In essential hypertensive patients with uncontrolled BP, despite the use of at least two antihypertensives, plasma renin and aldosterone concentrations and the transtubular potassium gradient (TTKG) were measured. Patients were treated with eplerenone 50 mg daily on top of their own medication. The office and ambulatory BP response and biochemical changes were evaluated after 1 week and 3 months of treatment and 6 weeks after discontinuation. Potential predictors for the change in 24-h ambulatory BP were tested in a multivariate regression model.

RESULTS

One hundred and seventeen patients with a mean age of 50.5 ± 6.6 years were included. Office BP decreased from 149/91 to 142/87 mmHg (P < 0.001) and ambulatory BP from 141/87 to 132/83 mmHg after 3 months of treatment (P < 0.001). Six weeks after discontinuation of eplerenone, office and ambulatory BP measurements returned to baseline values. Treatment resulted in a small rise in serum potassium and creatinine, and a small decrease in the TTKG. In a multivariate model, neither renin, aldosterone, or their ratio, nor the TTKG predicted the BP response. Only baseline ambulatory SBP predicted the BP response, whereas the presence of left ventricular hypertrophy was associated with a smaller BP reduction.

CONCLUSION

Add-on therapy with eplerenone effectively lowers BP in patients with difficult-to-treat primary hypertension. This effect is unrelated to circulating renin-angiotensin-aldosterone system activity and renal mineralocorticoid receptor activity as assessed by the TTKG.

Effect of spironolactone in patients with resistant arterial hypertension in relation to age and sex: insights from the aspirant trial

BACKGROUND

There are currently limited data on whether the effect of spironolactone in patients with resistant arterial hypertension depends on age and sex.

METHODS

Patients with an office systolic blood pressure (BP)>140 mmHg or diastolic BP>90 mmHg, despite treatment with at least 3 antihypertensive drugs including a diuretic, were randomly assigned to receive spironolactone or a placebo for 8 weeks in a double-blind, placebo-controlled, multicentre trial (ASPIRANT).

RESULTS

Analyses were done on 55 patients treated with spironolactone and 56 patients treated with placebo. Significant reductions of office systolic BP (-8.9±6.7 mmHg, P=0.012), 24-h ABPM systolic BP (-7.9±7.2 mmHg, P=0.032) and ABPM day-time systolic BP (-7.5±7.1 mmHg) after 8 weeks of spironolactone treatment, compared to placebo, were only observed in patients with a median age>62 years. The office and ABPM systolic BP reductions in patients aged ≤62 years and diastolic BP reductions by spironolactone in both age groups were not significant compared to placebo. Women tended to have a nonsignificantly higher reduction in systolic BP with spironolactone treatment, and there was no difference in diastolic BP reduction between women and men.

CONCLUSIONS

Spironolactone only leads to a reduction of systolic BP in older patients with resistant arterial hypertension aged >62 years, and is effective to a similar extent in men and women.

Eplerenone, an aldosterone blocker, is more effective in reducing blood pressure in patients with, than without, metabolic syndrome

BACKGROUND

Recently, the role of aldosterone in metabolic syndrome (MS) has aroused interest and several reports have suggested that aldosterone blockade could be beneficial in reducing blood pressure (BP).

METHODS

To examine the add-on effects of eplerenone (EP) on BP in patients with MS, 54 hypertensive patients with MS and 44 without MS were recruited. Systolic and diastolic BPs in mmHg before the initiation of EP was 144/84 ± 13/12 (MS group) and 147/85 ± 12/14 (non-MS group). Before the start of EP, all patients in both groups were treated with at least one antihypertensive drug. BPs were checked on every visit (at least every 2 months) and serum chemistries were measured every 4 months. The levels of microalbuminuria and aminoterminal pro-brain natriuretic peptide (NT pro-BNP) were determined before the start of and at the end of the study. Patients were followed for 1 year. If adverse effects were reported by patients or found in laboratory studies, EP was withdrawn.

RESULTS

One month after the start of EP, BPs were decreased to 140/80 ± 12/12 mmHg (MS group) versus 142/82 ± 11/12 mmHg (non-MS group) and there was no difference between the two groups. Towards the end of the study, BPs of both groups gradually decreased. At the end of the study, BPs of both groups were 129/76 ± 15/13 mmHg (MS group) versus 133/78 ± 13/11 mmHg (non-MS group). There was a significant difference in reduction of systolic BP between the two groups (p < 0.05). Add-on EP significantly decreased the levels of urinary excretion of albumin in MS patients but not in non-MS patients (p < 0.05). There was a significant correlation between reduction of systolic BP and NT pro-BNP but not microalbuminuria in the MS group (p < 0.05). There were no serious adverse effects in both groups.

CONCLUSION

EP may have some beneficial effects in lowering BP in patients with reduction of microalbuminuria.

Key advances in antihypertensive treatment

Although various effective treatments for hypertension are available, novel therapies to reduce elevated blood pressure, improve blood-pressure control, treat resistant hypertension, and reduce the associated cardiovascular risk factors are still required. A novel angiotensin-receptor blocker (ARB) was approved in 2011, and additional compounds are in development or being tested in clinical trials. Several of these agents have innovative mechanisms of action (an aldosterone synthase inhibitor, a natriuretic peptide agonist, a soluble epoxide hydrolase inhibitor, and an angiotensin II type 2 receptor agonist) or dual activity (a combined ARB and neutral endopeptidase inhibitor, an ARB and endothelin receptor A blocker, and an endothelin-converting enzyme and neutral endopeptidase inhibitor). In addition, several novel fixed-dose combinations of existing antihypertensive agents were approved in 2010-2011, including aliskiren double and triple combinations, and an olmesartan triple combination. Upcoming fixed-dose combinations are expected to introduce calcium-channel blockers other than amlodipine and diuretics other than hydrochlorothiazide. Finally, device-based approaches to the treatment of resistant hypertension, such as renal denervation and baroreceptor activation therapy, have shown promising results in clinical trials. However, technical improvements in the implantation procedure and devices used for baroreceptor activation therapy are required to address procedural safety concerns.

What is the role of aldosterone excess in resistant hypertension and how should it be investigated and treated?

Resistant hypertension has evolved as an important global health care problem. Primary aldosteronism is one of several potentially reversible causes of resistant hypertension. Primary aldosteronism can be effectively treated, when recognized, with a mineralocorticoid receptor antagonist, such as spironolactone and eplerenone. Each of these compounds can reduce blood pressure as monotherapy or when given with a range of other antihypertensive drug classes. These compounds have distinctive pharmacokinetic and pharmacodynamic patterns that require some forethought in their use before they are prescribed. However, as the use of mineralocorticoid-blocking agents has gradually increased, the hazards inherent to use of such drugs has become more apparent. Whereas the endocrine side effects of spironolactone are in most cases little more than a cosmetic annoyance, the potassium-sparing effects of both spironolactone and eplerenone can prove fatal if sufficient degrees of hyperkalemia develop. However, for most patients the risk of developing hyperkalemia in and of itself should not discourage the prudent clinician from bringing these compounds into play. Hyperkalemia should always be considered as a likelihood in any patient receiving one or the other of these medications. As such, steps should be taken to lessen the likelihood of it occurring if therapy is being contemplated with agents in this class.