Spironolactone has antiarrhythmic activity in ischaemic cardiac patients without cardiac failure

The effects of mineralocorticoid receptor antagonists on cardiovascular outcomes in patients with end-stage renal disease and heart failure

AIMS

Mineralocorticoid receptor antagonists (MRAs) have been shown to provide survival benefits in patients with heart failure; however, MRA use in patients with chronic kidney disease has been limited by safety concerns. The effects of MRAs on outcomes in patients with end-stage renal disease (ESRD) and heart failure remain unknown. The aim of this study was to evaluate the effects of MRAs on cardiovascular outcomes in patients with heart failure under maintenance dialysis in a real-world setting.

METHODS AND RESULTS

A retrospective cohort study was conducted by collecting data from the Taiwan National Health Insurance Research Database (NHIRD). Patients diagnosed with heart failure and ESRD and who started maintenance dialysis between 1 January 2001 and 31 December 2013 were identified. Patients were grouped according to MRA prescription. The outcomes of interest included cardiovascular (CV) death, hospitalization for heart failure (HHF), all-cause mortality, acute myocardial infarction (AMI), ischaemic stroke, any coronary revascularization procedures, and new-onset hyperkalaemia. Propensity score matching was performed at a 1:3 ratio between MRA users and non-users to minimize selection bias. A total of 50 872 patients who satisfied our inclusion and exclusion criteria were identified. After 1:3 matching, 2176 patients were included in the MRA group, and 6528 patients were included in the non-MRA group. The risk of CV death was significantly lower among patients who received MRAs than those who did not (hazard ratio [HR] 0.88, 95% confidence interval [CI] 0.80-0.95), as was the risk of all-cause mortality (HR 0.88, 95% CI 0.83-0.94). Reductions in the risks of CV death and all-cause mortality were more prominent among patients undergoing haemodialysis and those with coronary artery disease.

CONCLUSIONS

In patients undergoing regular dialysis who are diagnosed with heart failure, the use of MRAs is associated with lower risks of all-cause mortality and CV death. The benefits of MRA treatment in heart failure may persist in patients with ESRD. Further investigations through randomized controlled trials are needed to assess the efficacy and safety of MRAs in this high-risk population.

Effects of spironolactone on extrasystoles and heart rate variability in haemodialysis patients: a randomised crossover trial

BACKGROUND

Spironolactone treatment reduces mortality in haemodialysis (HD) patients. The objective of this study was to evaluate if spironolactone affects cardiac electric activity in this population.

METHODS

Participants were randomised to start with spironolactone 50 mg daily or observation (12 weeks) with subsequent washout (6 weeks) and crossover to the other intervention (12 weeks). Long-term electrocardiograms were recorded and assessed with blinding to treatment. The primary outcome was premature ventricular complexes (PVC), and secondary outcomes were atrial premature contractions (APC) and heart rate variability (HRV).

RESULTS

Thirty participants were recruited, and data for 16 participants were included in the analysis. Treatment was associated with an increase in PVCs by 9.7 [95% confidence interval (CI): 1.5 to 18] h^-1. HRV time-domain variables increased during treatment, the standard deviation of all beat-to-beat intervals by 18 (95% CI: 3.3 to 32) milliseconds (ms) and the standard deviation of the averages of beat-to-beat intervals in all 5-min segments of the entire recording by 16 (95% CI: 1.5 to 30) ms. There were no significant differences in other variables.

CONCLUSION

Spironolactone treatment increases PVCs in HD, indicating a possible proarrhythmic effect. However, improved cardiac autonomic function, as indicated by an increased HRV, may contribute to the survival benefit from spironolactone treatment in HD patients.

Update on antiarrhythmic drug pharmacology

Cardiac arrhythmias constitute a major public health problem. Pharmacological intervention remains mainstay to their clinical management. This, in turn, depends upon systematic drug classification schemes relating their molecular, cellular, and systems effects to clinical indications and therapeutic actions. This approach was first pioneered in the 1960s Vaughan-Williams classification. Subsequent progress in cardiac electrophysiological understanding led to a lag between the fundamental science and its clinical translation, partly addressed by The working group of the European Society of Cardiology (1991), which, however, did not emerge with formal classifications. We here utilize the recent Revised Oxford Classification Scheme to review antiarrhythmic drug pharmacology. We survey drugs and therapeutic targets offered by the more recently characterized ion channels, transporters, receptors, intracellular Ca²⁺ handling, and cell signaling molecules. These are organized into their strategic roles in cardiac electrophysiological function. Following analysis of the arrhythmic process itself, we consider (a) pharmacological agents directly targeting membrane function, particularly the Na⁺ and K⁺ ion channels underlying depolarizing and repolarizing events in the cardiac action potential. (b) We also consider agents that modify autonomic activity that, in turn, affects both the membrane and (c) the Ca²⁺ homeostatic and excitation-contraction coupling processes linking membrane excitation to contractile activation. Finally, we consider (d) drugs acting on more upstream energetic and structural remodeling processes currently the subject of clinical trials. Such systematic correlations of drug actions and arrhythmic mechanisms at different molecular to systems levels of cardiac function will facilitate current and future antiarrhythmic therapy.

Mineralocorticoid Antagonism and Vascular Function in Early Autosomal Dominant Polycystic Kidney Disease: A Randomized Controlled Trial

RATIONALE & OBJECTIVE

Vascular dysfunction, characterized by impaired vascular endothelial function and increased large-elastic artery stiffness, is evident early in autosomal dominant polycystic kidney disease (ADPKD) and is an important predictor of cardiovascular events and mortality. Aldosterone excess has been implicated in the development of endothelial dysfunction and arterial stiffness, in part by causing increased oxidative stress and inflammation. We hypothesized that aldosterone antagonism would reduce vascular dysfunction in patients with early-stage ADPKD.

STUDY DESIGN

Prospective, randomized, controlled, double-blind, clinical trial.

SETTING & PARTICIPANTS

61 adults aged 20 to 55 years with ADPKD, estimated glomerular filtration rate ≥ 60mL/min/1.73m², and receiving a renin-angiotensin-aldosterone system inhibitor.

INTERVENTION

Spironolactone (maximum dose, 50mg/d) or placebo for 24 weeks.

OUTCOMES

Change in brachial artery flow-mediated dilation (FMD_BA) was the primary end point and change in carotid-femoral pulse-wave velocity (CFPWV) was the secondary end point.

RESULTS

60 participants completed the trial. Participants had a mean age of 34±10 (SD) years, 54% were women, and 84% were non-Hispanic white. Spironolactone did not change FMD_BA (8.0% ± 5.5% and 7.8% ± 4.3% at baseline and 24 weeks, respectively, vs corresponding values in the placebo group of 8.4% ± 6.2% and 8.0% ± 4.6%; P=0.9for comparison of change between groups) or CFPWV (640±127 and 603±101cm/s at baseline and 24 weeks, respectively, vs corresponding values in the placebo group of 659±138 and 658±131cm/s; P=0.1). Brachial systolic blood pressure was reduced with spironolactone (median change, -6 [IQR, -15, 1] vs -2 [IQR, -7, 10] mm Hg in the placebo group; P=0.04). Spironolactone did not change the majority of circulating and/or endothelial cell markers of oxidative stress/inflammation and did not change vascular oxidative stress.

LIMITATIONS

Low level of baseline vascular dysfunction; lack of aldosterone measurements.

CONCLUSIONS

24 weeks of aldosterone antagonism reduced systolic blood pressure without changing vascular function in patients with early-stage ADPKD.

FUNDING

NIDDK, NIH National Center for Advancing Translational Sciences, and the Zell Family Foundation.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov with study number NCT01853553.

Drug-induced Inhibition and Trafficking Disruption of ion Channels: Pathogenesis of QT Abnormalities and Drug-induced Fatal Arrhythmias

Risk of severe and fatal ventricular arrhythmias, presenting as Torsade de Pointes (TdP), is increased in congenital and acquired forms of long QT syndromes (LQTS). Drug-induced inhibition of K+ currents, IKs, IKr, IK1, and/or Ito, delay repolarization, prolong QT, and increase the risk of TdP. Drug-induced interference with IKr is the most common cause of acquired LQTS/TdP. Multiple drugs bind to KNCH2-hERG-K+ channels affecting IKr, including antiarrythmics, antibiotics, antivirals, azole-antifungals, antimalarials, anticancer, antiemetics, prokinetics, antipsychotics, and antidepressants. Azithromycin has been recently added to this list. In addition to direct channel inhibition, some drugs interfere with the traffic of channels from the endoplasmic reticulum to the cell membrane, decreasing mature channel membrane density; e.g., pentamidine, geldalamicin, arsenic trioxide, digoxin, and probucol. Other drugs, such as ketoconazole, fluoxetine, norfluoxetine, citalopram, escitalopram, donepezil, tamoxifen, endoxifen, atazanavir, and roxitromycin, induce both direct channel inhibition and impaired channel trafficking. Although many drugs prolong the QT interval, TdP is a rare event. The following conditions increase the risk of drug-induced TdP: a) Disease states/electrolyte levels (heart failure, structural cardiac disease, bradycardia, hypokalemia); b) Pharmacogenomic variables (presence of congenital LQTS, subclinical ion-channel mutations, history of or having a relative with history of drug-induced long QT/TdP); c) Pharmacodynamic and kinetic factors (high doses, women, elderly, metabolism inhibitors, combining two or more QT prolonging drugs, drugs that prolong the QT and increase QT dispersion, and drugs with multiple actions on ion channels). Because most of these conditions are preventable, careful evaluation of risk factors and increased knowledge of drug use associated with repolarization abnormalities are strongly recommended.

Influence of steroid hormones on ventricular repolarization

QT interval prolongation, corrected for heart rate (QTc), either spontaneous or drug-induced, is associated with an increased risk of torsades de pointes and sudden death. Women have longer QTc than men and are at higher risk of torsades de pointes, particularly during post-partum and the follicular phase. Men with peripheral hypogonadism have longer QTc than healthy controls. The role of the main sex steroid hormones has been extensively studied with inconsistent findings. Overall, estradiol is considered to promote QTc lengthening while progesterone and testosterone shorten QTc. New findings suggest more complex regulation of QTc by sex steroid hormones involving gonadotropins (i.e. follicle-stimulating hormone), the relative concentrations of sex steroid hormones (which depends on gender, i.e., progesterone/estradiol ratio in women). Aldosterone, another structurally related steroid hormone, can also prolong ventricular repolarization in both sex. Better understanding of pathophysiological hormonal processes which may lead to increased susceptibility of women (and possibly hypogonadic men) to drug-induced arrhythmia may foster preventive treatments (e.g. progesterone in women). Exogenous hormonal intake might offer new therapeutic opportunities or, alternatively, increase the risk of torsades de pointes. Some exogenous sex steroids may also have paradoxical effects on ventricular repolarization. Lastly, variations of QTc in women linked to the menstrual cycle and sex hormone fluctuations are generally ignored in regulatory thorough QT studies. Investigators and regulatory agencies promoting inclusion of women in thorough QT studies should be aware of this source of variability especially when studying drugs over several days of administration.

Spironolactone Effect in Hepatic Ischemia/Reperfusion Injury in Wistar Rats

Introduction. Ischemia/reperfusion (IR) injury, often associated with liver surgery, is an unresolved problem in the clinical practice. Spironolactone is an antagonist of aldosterone that has shown benefits over IR injury in several tissues, but its effects in hepatic IR are unknown. Objective. To evaluate the effect of spironolactone on IR-induced damage in liver. Materials and Methods. Total hepatic ischemia was induced in rats for 20 min followed by 60 min of reperfusion. Spironolactone was administered and hepatic injury, cytokine production, and oxidative stress were assessed. Results. After IR, increased transaminases levels and widespread acute inflammatory infiltrate, disorganization of hepatic hemorrhage trabeculae, and presence of apoptotic bodies were observed. Administration of SPI reduced biochemical and histological parameters of liver injury. SPI treatment increased IL-6 levels when compared with IR group but did not modify either IL-1β or TNF-α with respect to IR group. Regarding oxidative stress, increased levels of catalase activity were recorded in IR + SPI group in comparison with group without treatment, whereas MDA levels were similar in IR + SPI and IR groups. Conclusions. Spironolactone reduced the liver damage induced by IR, and this was associated with an increase in IL-6 production and catalase activity.

Rapid and MR-Independent IK1 Activation by Aldosterone during Ischemia-Reperfusion

In ST elevation myocardial infarction (STEMI) context, clinical studies have shown the deleterious effect of high aldosterone levels on ventricular arrhythmia occurrence and cardiac mortality. Previous in vitro reports showed that during ischemia-reperfusion, aldosterone modulates K⁺ currents involved in the holding of the resting membrane potential (RMP). The aim of this study was to assess the electrophysiological impact of aldosterone on I_K1 current during myocardial ischemia-reperfusion. We used an in vitro model of “border zone” using right rabbit ventricle and standard microelectrode technique followed by cell-attached recordings from freshly isolated rabbit ventricular cardiomyocytes. In microelectrode experiments, aldosterone (10 and 100 nmol/L, n=7 respectively) increased the action potential duration (APD) dispersion at 90% between ischemic and normoxic zones (from 95±4 ms to 116±6 ms and 127±5 ms respectively, P<0.05) and reperfusion-induced sustained premature ventricular contractions occurrence (from 2/12 to 5/7 preparations, P<0.05). Conversely, potassium canrenoate 100 nmol/L and RU 28318 1 μmol/l alone did not affect AP parameters and premature ventricular contractions occurrence (except Vmax which was decreased by potassium canrenoate during simulated-ischemia). Furthermore, aldosterone induced a RMP hyperpolarization, evoking an implication of a K⁺ current involved in the holding of the RMP. Cell-attached recordings showed that aldosterone 10 nmol/L quickly activated (within 6.2±0.4 min) a 30 pS K⁺-selective current, inward rectifier, with pharmacological and biophysical properties consistent with the I_K1 current (NPo =1.9±0.4 in control vs NPo=3.0±0.4, n=10, P<0.05). These deleterious effects persisted in presence of RU 28318, a specific MR antagonist, and were successfully prevented by potassium canrenoate, a non specific MR antagonist, in both microelectrode and patch-clamp recordings, thus indicating a MR-independent I_K1 activation. In this ischemia-reperfusion context, aldosterone induced rapid and MR-independent deleterious effects including an arrhythmia substrate (increased APD₉₀ dispersion) and triggered activities (increased premature ventricular contractions occurrence on reperfusion) possibly related to direct I_K1 activation.

Role of mineralocorticoid receptor antagonists in cardiovascular disease

Aldosterone exerts its best known sodium homeostasis actions by controlling sodium excretion at the level of the distal tubules via activation of the apical epithelial sodium channel and the basolateral Na(+)/K(+)ATPase pump. Recently, this mineralocorticoid hormone has been demonstrated to act on the heart and blood vessels. Excess release of aldosterone in relation to the salt status induces both genomic and nongenomic effects that by promoting endothelial dysfunction, and vascular and cardiorenal adverse remodeling, contribute to the target organ damage found in hypertension, heart failure, myocardial infarction, and chronic renal failure. Mineralocorticoid receptor blockers have been shown to be highly effective in resistant hypertension and to slow down heart failure progression, and in experimental animals, the development of atherosclerosis. Blockade of the action of aldosterone and potentially other mineralocorticoid steroids has been increasingly demonstrated to be an extremely beneficial therapy in different forms of cardiovascular disease. This review provides a summary of the knowledge that exists on aldosterone actions in the cardiovascular system and, in providing the translational impact of this knowledge to the clinical arena, illustrates how much more needs to be achieved in exploring the use of mineralocorticoid receptor blockers in less advanced stages of heart, renal, and vascular disease.

Time and technology will tell: the pathophysiologic basis of neurohormonal modulation in heart failure

The central roles of neurohormonal abnormalities in the pathobiology of heart failure have been defined in recent decades. Experiments have revealed both systemic involvement and intricate subcellular regulation by circulating effectors of the sympathetic nervous system, the renin-angiotensin-aldosterone system, and others. Randomized clinical trials substantiated these findings, establishing neurohormonal antagonists as cornerstones of heart failure pharmacotherapy, and occasionally offering further insight on mode of benefit. This review discusses the use of β-blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and aldosterone receptor antagonists in the treatment of heart failure, with particular attention to the pathophysiologic basis and mechanisms of action.

Targeting the renin-angiotensin-aldosterone system in heart failure

The renin-angiotensin-aldosterone system is a well-established therapeutic target in the treatment of heart failure (HF). Substantial advances have been made with existing agents--angiotensin-converting enzyme (ACE) inhibitors, angiotensin II-receptor blockers (ARBs), and mineralocorticoid-receptor antagonists (MRAs)--and new data continue to emerge. The indication for the use of MRAs has been broadened to include potentially all patients who have HF with reduced ejection fraction (HFrEF), and ACE inhibitors might have a novel application in patients who are at risk of left ventricular dysfunction (those with aortic valvular disease or pacing-induced heart disease). ARBs have been shown to be a beneficial alternative to ACE inhibitors in HFrEF, but their value when added to ACE inhibitors has been questioned. Upstream, direct renin blockade with aliskiren is being pursued in two large trials of HF, despite the premature halting of a third study. A substantial, unmet need remains in patients who have HF with preserved ejection fraction (HFpEF). New data on spironolactone and LCZ696 (a combined ARB and neprilysin inhibitor) show promise for these patients. Results of the TOPCAT study of spironolactone in patients with HFpEF are awaited, and LCZ696 is now being tested in a large trial in patients with HFrEF.

Aldosterone receptor antagonists in cardiovascular disease: a review of the recent literature and insight into potential future indications

Randomized controlled trials demonstrate the efficacy of aldosterone receptor antagonists (spironolactone and eplerenone) as a useful pharmacologic intervention specifically in patients with New York Heart Association (NYHA) class III and IV heart failure, in patients with an ejection fraction <40% after myocardial infarction, and most recently in patients with mildly symptomatic heart failure. However, aldosterone receptor antagonists may be beneficial in a broader patient population. Aldosterone receptor antagonists can potentially serve as an antiarrhythmic pharmacologic agent for atrial and ventricular arrhythmias, an anti-ischemic medication in coronary artery disease through prevention of myocardial fibrosis and vascular damage, and as an agent in people with asymptomatic and mild heart failure (NYHA classes I and II) and diastolic heart failure. However, many clinicians remain reluctant to prescribe this highly efficacious pharmacologic therapy for a variety of reasons, including concerns about polypharmacy and hyperkalemia. Recent observational analysis demonstrates that less than one-third of eligible patients hospitalized with heart failure actually received aldosterone antagonist therapy. This article will review the current and potential future uses of aldosterone receptor antagonists across the entire spectrum of cardiovascular disease. The authors have no funding, financial relationships, or conflicts of interest to disclose.

The effect of aldosterone antagonists for ventricular arrhythmia: a meta-analysis

BACKGROUND

Sudden cardiac death (SCD) from cardiac arrest, one of the most common types of cardiac-related death, is most often triggered by ventricular arrhythmia (VA). It has been reported that aldosterone antagonists (AAs) have the benefit of reducing SCD in patients with heart failure (HF). It also has been indicated in animal experiments and clinical trials that AAs may have an antiarrhythmic effect.

HYPOTHESIS

AAs have an effect on VA in patients with HF or coronary artery disease.

METHODS

We searched the Cochrane Central Register of Controlled Trials, PubMed, Current Controlled Trials, and the National Research Register, and identified randomized controlled trials on the effect of AAs on VA.

RESULTS

All together, 7 trials with a total of 8635 patients were identified and extracted. AAs reduced the risk of SCD in patients with HF by 21% (relative risk [RR]: 0.79, 95% confidence interval [CI]: 0.67-0.93). AAs significantly reduced the episodes of ventricular premature complexes (mean difference 705 ± 646 episodes per 24 hours). Risk of ventricular tachycardia was reduced by 72% (RR: 0.28, 95% CI: 0.10-0.77).

CONCLUSIONS

The additional administration of AAs in patients with HF or coronary artery disease shows a benefit in reducing the risk of SCD and may also be effective for reducing episodes of ventricular premature complexes and ventricular tachycardia.

Plasma aldosterone levels are associated with increased cardiovascular mortality: the Ludwigshafen Risk and Cardiovascular Health (LURIC) study

AIMS

Evidence has accumulated that elevated aldosterone levels are associated with increased risks of fatal cardiovascular (CV) events. With the present analysis, we aimed at evaluating prospectively whether plasma aldosterone correlates with all-cause and CV disease (CVD) mortality in a large cohort of patients.

METHODS AND RESULTS

Median plasma aldosterone concentration (PAC) was 79.0 (48.0-124.0) pg/mL (normal range: 30-160) in 3153 patients [median age: 63.5 (56.3-70.6) years; 30.1% women] who had undergone coronary angiography. After a median follow-up of 7.7 (7.2-8.5) years, a total of 716 participants died [22.7%; 454 (14.4%) due to CV causes and 262 (8.3%) due to non-CV causes]. In multivariable Cox proportional hazard analysis, adjusted for age, gender, antihypertensive treatment, and established CV risk factors, PAC levels stratified in quartiles were significantly associated with all-cause and CVD mortality. Compared with the reference (first) PAC quartile, hazard ratios (confidence interval 95%) for the fourth, third, and second PAC quartiles were 1.30 (1.02-1.65, P = 0.033), 1.32 (1.04-1.68, P = 0.021), and 1.20 (0.93-1.54, P = 0.155) for total mortality and 1.58 (1.15-2.16, P = 0.004), 1.39 (1.01-1.90, P = 0.041), and 1.63 (1.20-2.20, P = 0.002) for CVD mortality, respectively. Analyses for specific causes of CV death revealed strong associations between PAC levels and higher risk for fatal stroke and sudden cardiac death.

CONCLUSION

In a large cohort of patients scheduled for coronary angiography, variation in PAC levels within the normal range is associated with increased all-cause and CVD mortality independent of major established CV risk factors.

Aldosterone-receptor antagonism in hypertension

The role of the renin-angiotensin-aldosterone system (RAAS) in hypertension has since long been recognized and aldosterone has been acknowledged as one of the key hormones in the pathophysiology, not only in primary aldosteronism but also in essential hypertension and drug-resistant hypertension. Aldosterone-receptor antagonists (ARAs) are increasingly used in patients with resistant hypertension, often with impressive results. However, definitive evidence for the benefit of ARAs in these patients from randomized, controlled trials is lacking. This review gives an overview of the current data on this topic. Future studies should focus on the identification of factors that are able to predict the response to treatment, as to select patients who will benefit most from treatment with ARAs. On the basis of the current knowledge, we recommend prescription of ARAs to patients with primary aldosteronism, resistant hypertension and patients with hypertension and hypokalemia.

Spironolactone for poorly controlled hypertension in type 2 diabetes: conflicting effects on blood pressure, endothelial function, glycaemic control and hormonal profiles

AIMS/HYPOTHESIS

Aldosterone antagonism improves endothelial function (and reduces deaths) in chronic heart failure. It is not known whether similar effects occur in other high-risk groups such as patients with diabetes and hypertension. We therefore assessed the full effects of aldosterone blockade in poorly controlled hypertensive patients with type 2 diabetes, focussing on blood pressure, endothelial function, glycaemic control and key hormones.

METHODS

We performed a randomised, placebo-controlled, double-blind, crossover study on 50 patients with type 2 diabetes and treated but poorly controlled hypertension, comparing spironolactone versus placebo. Patients had their endothelial function assessed by standard forearm venous occlusion plethysmography.

RESULTS

There was no significant improvement in endothelium-dependent vasodilatation in response to acetylcholine, despite highly significant reductions in systolic and diastolic blood pressure. However, spironolactone significantly worsened glycaemic control, plasma angiotensin II and cortisol.

CONCLUSIONS/INTERPRETATION

Spironolactone is highly effective in lowering blood pressure in patients with type 2 diabetes and poorly controlled hypertension on standard treatment, but does not improve vascular endothelial function in this group. We speculate that any tendency for the spironolactone-induced lowering of blood pressure to improve endothelial function is offset by its tendency to worsen glycaemic control and increase the levels of angiotensin II and even possibly cortisol.