Spironolactone-induced renal insufficiency and hyperkalemia in patients with heart failure

Extra-adrenal aldosterone: a mini review focusing on the physiology and pathophysiology of intrarenal aldosterone

PURPOSE

Accumulating evidence has demonstrated the existence of extra-adrenal aldosterone in various tissues, including the brain, heart, vascular, adipocyte, and kidney, mainly based on the detection of the CYP11B2 (aldosterone synthase, cytochrome P450, family 11, subfamily B, polypeptide 2) expression using semi-quantitative methods including reverse transcription-polymerase chain reaction and antibody-based western blotting, as well as local tissue aldosterone levels by antibody-based immunosorbent assays. This mini-review highlights the current evidence and challenges in extra-adrenal aldosterone, focusing on intrarenal aldosterone.

METHODS

A narrative review.

RESULTS

Locally synthesized aldosterone may play a vital role in various physio-pathological processes, especially cardiovascular events. The site of local aldosterone synthesis in the kidney may include the mesangial cells, podocytes, proximal tubules, and collecting ducts. The synthesis of renal aldosterone may be regulated by (pro)renin receptor/(pro)renin, angiotensin II/Angiotensin II type 1 receptor, wnt/β-catenin, cyclooxygenase-2/prostaglandin E2, and klotho. Enhanced renal aldosterone release promotes Na+ reabsorption and K+ excretion in the distal nephron and may contribute to the progress of diabetic nephropathy and salt-related hypertension.

CONCLUSIONS

Inhibition of intrarenal aldosterone signaling by aldosterone synthase inhibitors or mineralocorticoid receptor antagonists may be a hopeful pharmacological technique for the therapy of diabetic nephropathy and saltrelated hypertension. Yet, current reports are often conflicting or ambiguous, leading many to question whether extra-adrenal aldosterone exists, or whether it is of any physiological and pathophysiological significance.

Nephrotoxic drug burden and predictors of exposure among patients with renal impairment in Ethiopia: A multi-center study

Background

Nephrotoxic drugs may hasten the decline in kidney function and worsen the progression of renal impairment as a result; these drugs should be avoided or used with caution in patients with pre-existing renal insufficiency. The purpose of this study was to assess the burden of nephrotoxic medication use and its predictors among patients with underlying renal impairment.

Methods

A multicenter, institution-based, cross-sectional study was conducted from May 30, 2021 to July 30, 2021, at medical wards. Renal impaired patients admitted during the data collection period who took at least one medication were enrolled in the study. A simple random sampling technique was used to select the study participants. Data was collected through an interview and a medical card review. Both bivariable and multivariable binary logistic regression analyses were fitted to identify factors associated with nephrotoxic drug use.

Results

Among the 422 participants, more than half of them (53.6 %) were male. The mean patient's age was 47.5 (±16.7) years. A total of 1310 drugs were prescribed for 422 patients with renal impairment, of which 80.15 % were nephrotoxic. Nephrotoxic drugs were prescribed for 66.4 % of patients. The burden of nephrotoxic medication prescription was significantly associated with variables like the presence of comorbidity (AOR = 6.31, 95 % CI: 2.01-19.79), the number of medications prescribed (AOR = 1.43, 95 % CI: 1.05-1.93), and the age of participants (AOR = 1.12, 95 % CI: 1.07-1.17).

Conclusion

The present study demonstrated that two-third of the patients with renal impairment were exposed to nephrotoxic medications. Furosemide, Enalapril, and vancomycin were the most frequently prescribed nephrotoxic medications. The study suggests that prescribers need to give special attention to older patients who have underlying renal insufficiency, a comorbid condition, and polypharmacy regarding exposure to contraindicated nephrotoxic medication.

Outcomes in patients with cardiometabolic disease who develop hyperkalemia while treated with a renin-angiotensin-aldosterone system inhibitor

BACKGROUND

Many patients with indications for renin-angiotensin-aldosterone system inhibitor (RAASi) therapy are not receiving these medications. Concern about hyperkalemia is thought to contribute to this lack of evidence-based therapy.

METHODS

A retrospective cohort study included adult patients in primary care practices affiliated with an integrated health care delivery system treated with RAASi between 2000 and 2019 for any of the following indications: (a) coronary artery disease (CAD); (b) heart failure (HF) with a left ventricle ejection fraction ≤ 40%; (c) diabetes mellitus (DM) with proteinuria; or (d) chronic kidney disease (CKD) with proteinuria. Relationship between hyperkalemia (K > 5.0 mEg/L) over the first 12 months of follow-up and a composite end point of cardiovascular events, renal dysfunction, and all-cause mortality was evaluated.

RESULTS

Among 82,732 study patients, 7,727 (9.34%) developed hyperkalemia. Patients with hyperkalemia were older (69.0 vs 64.6) and more likely to have CAD (57.8 vs 53.7%), CKD (57.3 vs 51.1%), HF (19.3 vs 9.7%), and DM (45.3 vs 33.3%) (P < .001 for all). Five-year cumulative risk of the primary outcome was higher in patients who did (63.9%; 95% CI: 62.8%-65.1%) versus did not (37.2%; 95% CI: 36.8%-37.6%) develop hyperkalemia. Five-year cumulative risk of ED visit or hospitalization for hyperkalemia was 15.6% (14.7%-16.6%) for patients with versus 2.7% (95% CI: 2.6-2.9) for patients without hyperkalemia, rising to 25.9% (95% CI: 22.4-29.9) for patients with severe (K > 6.0 mEq/dL) hyperkalemia. Patients who experienced hyperkalemia were more likely (34.4%) than patients who did not (29.2%) to deintensify RAASi therapy (P < .001). Five-year cumulative risk of the primary outcome was higher in patients who lowered RAASi dose (50.4%; 95% CI: 48.5%-52.4%) or stopped RAASi therapy completely (49.3%; 95% CI: 48.5%-50.1%), compared to patients who continued RAASi therapy (36.1%; 95% CI: 25.7-36.5). Similar findings were observed in multivariable analyses and for individual components of the primary outcome.

CONCLUSIONS

Hyperkalemia is a common complication of RAASi therapy and is associated with an increased risk of multiple adverse outcomes. Patients who have their RAASi medications deintensified after a hyperkalemic event have higher incidence of cardiovascular events, renal dysfunction and death.

Collecting duct renin regulates potassium homeostasis in mice

AIM

The kaliuretic action of the renin-angiotensin-aldosterone system (RAAS) is well established as highlighted by hyperkalemia side effect of RAAS inhibitors but such action is usually ascribed to systemic RAAS. The present study addresses the involvement of intrarenal RAAS in K+ homeostasis with emphasis on locally generated renin within the collecting duct (CD).

METHODS

Wild-type (Floxed) and CD-specific deletion of renin (CD renin KO) mice were treated for 7 days with a high K+ (HK) diet to investigate the role of CD renin in kaliuresis regulation and further define the underlying mechanism with emphasis on analysis of intrarenal aldosterone biosynthesis.

RESULTS

In floxed mice, renin levels were elevated in the renal medulla and urine following a 1-week HK diet, indicating activation of the intrarenal renin. CD renin KO mice had blunted HK-induced intrarenal renin response and developed impaired kaliuresis and elevated plasma K+ level (4.45 ± 0.14 vs. 3.89 ± 0.04 mM, p < 0.01). In parallel, HK-induced intrarenal aldosterone and CYP11B2 expression along with expression of renal outer medullary K+ channel (ROMK), calcium-activated potassium channel subunit alpha-1 (α-BK), α-Na+ -K+ -ATPase, and epithelial sodium channel (β-ENaC and cleaved-γ-ENaC) expression were all significantly blunted in CD renin KO mice in contrast to the unaltered responses of plasma aldosterone and adrenal CYP11B2.

CONCLUSION

Taken together, these results support a kaliuretic action of CD renin during HK intake.

Hospital Variation of Spironolactone Use in Patients Hospitalized for Heart Failure in China-The China PEACE Retrospective Heart Failure Study

Background Although aldosterone antagonists improve outcomes in select individuals with heart failure and reduced ejection fraction, studies in the United States have raised concerns about underuse and overuse. Variations in the prescription of aldosterone antagonist in China are unknown. Methods and Results In the multicenter, hospital-based, retrospective China PEACE (China Patient-Centered Evaluative Assessment of Cardiac Events) study, we identified a nationally representative cohort of admissions for heart failure in a nationally representative sample of Chinese hospitals in 2015. Patients were classified into 1 of 3 groups according to their eligibility for spironolactone-"ideal" (left ventricular ejection fraction <40% and without contraindications), "contraindicated" (a documented contraindication, irrespective of left ventricular ejection fraction), and "uncertain-benefit" (all others). We measured hospital variation of spironolactone prescriptions at discharge in the "ideal" and "contraindicated" group and calculated the median odds ratio (MOR), a measure of institution-level variation for 2 individuals with similar characteristics discharged at 2 randomly selected hospitals. Hospital characteristics associated with spironolactone use were identified using multivariable linear regression model. Among 1222 ideal patients from 97 hospitals, the median rate of spironolactone prescription was 78.6% (interquartile range [IQR], 42.8%-89.6% [range, 0%-100%], MOR, 3.4 [95% CI, 2.7-4.0]) at discharge. Among 900 contraindicated patients from 83 hospitals, the median rate of spironolactone prescription was 30.0% (IQR, 9.1%-50.0% [range, 0%-100%], MOR, 3.1 [95% CI, 2.4-3.9]) at discharge. Hospitals with independent departments of cardiology and located in Eastern China were associated with a 38.0% (95% CI, 18.7-57.3; P<0.001) and a 14.6% (95% CI, 2.3%-26.9%; P=0.020) higher rate of spironolactone use for ideal patients. Conclusions In this national study of hospitals in China, the use of spironolactone among ideal patients and the inappropriate use of spironolactone among patients with contraindications was substantial, with rates that varied markedly by institution. Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT02877914.

Soluble (Pro)Renin Receptor as a Negative Regulator of NCC (Na+-Cl- Cotransporter) Activity

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Beta-blocker therapy in elderly patients with renal dysfunction and heart failure

OBJECTIVE

To assess the role of beta-blockers (BB) in patients with chronic kidney disease (CKD) aged ≥ 75 years.

METHODS AND RESULTS

From January 2008 to July 2014, we included 390 consecutive patients ≥ 75 years of age with ejection fraction ≤ 35% and glomerular filtration rate (GFR) ≤ 60 mL/min per 1.73 m². We analyzed the relationship between treatment with BB and mortality or cardiovascular events. The mean age of our population was 82.6 ± 4.1 years. Mean ejection fraction was 27.9% ± 6.5%. GFR was 60-45 mL/min per 1.73 m² in 50.3% of patients, 45-30 mL/min per 1.73 m² in 37.4%, and < 30 mL/min per 1.73 m ² in 12.3%. At the conclusion of follow-up, 67.4% of patients were receiving BB. The median follow-up was 28.04 (IR: 19.41-36.67) months. During the study period, 211 patients (54.1%) died and 257 (65.9%) had a major cardiovascular event (death or hospitalization for heart failure). BB use was significantly associated with a reduced risk of death (HR = 0.51, 95% CI: 0.35-0.74;P < 0.001). Patients receiving BB consistently showed a reduced risk of death across the different stages of CKD: stage IIIa (GFR = 30-45 mL/min per 1.73 m ²; HR = 0.47, 95% CI: 0.26-0.86,P < 0.0001), stage IIIb (GFR 30-45 mL/min per 1.73 m ²; HR = 0.55, 95% CI: 0.26-1.06,P = 0.007), and stages IV and V (GFR < 30 mL/min per 1.73 m ²; HR = 0.29, 95% CI: 0.11-0.76;P = 0.047).

CONCLUSIONS

The use of BB in elderly patients with HFrEF and renal impairment was associated with a better prognosis. Use of BB should be encouraged when possible.

Mineralocorticoid Receptor Antagonist Utilization in a Nationally Representative Heart Failure With Reduced Ejection Fraction Outpatient Population: A Cross-Sectional Study

BACKGROUND

Mineralocorticoid receptor antagonists (MRAs) improve survival among patients with heart failure with reduced ejection fraction (HFrEF); however, studies have identified low utilization rates. No study has evaluated the prevalence and predictors of MRA prescribing in a nationally representative outpatient cohort.

STUDY QUESTION

What is the prevalence and predictors of MRA prescribing among outpatients with HFrEF in the United States?

STUDY DESIGN

A national cross-sectional secondary analysis of the National Ambulatory Medical Care Survey from 2007 to 2014 including all office visits for HFrEF in patients aged >55 years. Office visits involving patients with any history of chronic renal failure and hyperkalemia were excluded.

MEASURES AND OUTCOMES

The primary end point was the MRA prescribing rate. Multivariable logistic regression models were created to identify predictors of use.

RESULTS

In total, 1259 visits were eligible for inclusion, representing more than 30 million visits when weighted. MRAs were initiated or continued in 11.1% of HFrEF visits (95% confidence interval [CI] 8.8-13.8). In the full model, predictors included diabetes mellitus (OR 2.27; 95% CI 1.12-4.61), Northeast region (OR 0.20; 95% CI 0.05-0.74), and ≥4 chronic conditions (OR 0.26; 95% CI 0.10-0.71). Among symptomatic patients, predictors included non-Hispanic black patients (OR 4.55; 95% CI 1.81-11.43), patients aged 65-74 years (OR 3.38; 95% CI 1.53-7.44), and office systolic blood pressure >130 mm Hg (OR 0.31; 95% CI 0.16-0.60). Physician specialty, visit year, patient sex, and payor type were not significant predictors of MRA utilization.

CONCLUSIONS

Although significant data support the use of MRA in HFrEF, utilization is lower than previously estimated.

Hyperkalemia and Acute Kidney Injury with Spironolactone Use Among Patients with Heart Failure

OBJECTIVE

To quantify the risk of hyperkalemia and acute kidney injury (AKI) when spironolactone use is added on to loop diuretic use among patients with heart failure, and to evaluate whether the risk is modified by level of kidney function.

METHODS

We identified 17,110 patients with heart failure treated with loop diuretics between January 1, 2004, and December 31, 2016 within the Geisinger Health System. We estimated the incidence of hyperkalemia and AKI associated with spironolactone initiation, and used target trial emulation methods to minimize confounding by indication.

RESULTS

During a mean follow-up of 134 mo, 3229 of 17,110 patients (18.9%) initiated spironolactone. Incidence rates of hyperkalemia and AKI in patients using spironolactone with a loop diuretic were 2.9 and 10.1 events per 1000 person-months, respectively. In propensity score-matched analyses, spironolactone initiation was associated with higher hyperkalemia and AKI risk compared with loop alone (hazard ratio, 1.69; 95% CI, 1.35 to 2.10; P<.001, and hazard ratio, 1.12; 95% CI, 1.00 to 1.26; P=.04, respectively). There were no differences in the relative risk of either outcome associated with spironolactone by level of kidney function.

CONCLUSION

The addition of spironolactone to loop diuretics in patients with heart failure was associated with higher risk of hyperkalemia and AKI; these risks must be weighed against the potential benefits of spironolactone.

Hyperkalemia and management of renin-angiotensin-aldosterone system inhibitors in chronic heart failure with reduced ejection fraction: A systematic review

INTRODUCTION AND OBJECTIVES

Renin-angiotensin-aldosterone system inhibitors (RAASi) are the cornerstone of treatment of heart failure with reduced ejection fraction (HFrEF). RAASi optimization in real-life care is challenged by hyperkalemia, a potentially fatal adverse event, which can necessitate downtitration or discontinuation of RAASi and negatively impact survival in HFrEF. The literature on this problem is sparse. We performed a systematic review of studies on HFrEF to investigate the prevalence, incidence, and risk factors of hyperkalemia, RAASi prescription rates, frequency of RAASi downtitration or discontinuation due to hyperkalemia, and the potential negative effect of the latter on prognosis.

METHODS

We conducted a MEDLINE (PubMed) search including observational and interventional studies published between January 1987 and May 2018.

RESULTS

A total of 30 observational and 18 interventional studies were included in the review. The incidence of hyperkalemia reported was between 0% and 63% in observational studies and was between 0% and 30% in clinical trials. Risk factors for hyperkalemia included RAASi prescription, older age, diabetes, and chronic kidney disease. In real-life studies, RAASi were downtitrated or discontinued in 3-22% of HFrEF patients; hyperkalemia was the reported cause in 5% of cases. No reports were found on the impact on prognosis of RAASi downtitration or discontinuation due to hyperkalemia.

CONCLUSIONS

Hyperkalemia and RAASi downtitration or discontinuation are frequent, particularly in real-life HFrEF studies. Further research is needed to clarify the role of RAASi downtitration or discontinuation due to hyperkalemia and to assess its long-term prognostic impact in HFrEF patients.

Blockade of Renin-Angiotensin-Aldosterone System in Elderly Patients with Heart Failure and Chronic Kidney Disease: Results of a Single-Center, Observational Cohort Study

BACKGROUND

Angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (ACEis/ARBs) and mineralocorticoid receptor antagonists (MRAs) have been shown to benefit patients with heart failure with reduced ejection fraction (HFrEF). However, there is a lack of information on the advantages of these drugs for patients with chronic kidney disease (CKD), and this gap is especially pronounced in elderly patients.

OBJECTIVE

The objective of this study was to assess the role of treatment consisting of ACEi/ARBs and MRAs in patients ≥ 75 years of age with CKD.

METHODS

From January 2008 to July 2014, 390 consecutive patients ≥ 75 years of age with an ejection fraction ≤ 35% and a glomerular filtration rate (GFR) ≤ 60 mL/min/1.73 m² were included. We analyzed the relationship between treatment with ACEi/ARBs and MRAs and mortality or cardiovascular events.

RESULTS

Three hundred and ninety patients were included, with a mean age of 82.6 ± 4.1 years. Mean ejection fraction was 27.9 ± 6.5%. Renal dysfunction was mild (GFR 45-60 mL/min/1.73 m²) in 50.3% of patients, moderate (GFR 30-44 mL/min/1.73 m²) in 37.4%, and severe (GFR < 30 mL/min/1.73 m²) in 12.3%. After 32 ± 23 months, 68.7% of patients were receiving ACEi/ARBs and 40% were receiving MRAs; 65.9% developed a cardiovascular event and 54.4% had died. After multivariate Cox regression analysis, ACEi/ARB treatment was independently associated with a decreased rate of cardiovascular events (hazard ratio 0.71 [95% confidence interval 0.50-0.98]) and MRAs were not associated with a decrease in cardiovascular events or total mortality.

CONCLUSIONS

Treatment with ACEi/ARBs in elderly patients with HFrEF and CKD was associated with a lower rate of cardiovascular events, though MRA treatment failed to reduce the risk of morbidity and mortality in our population.

Comparison of Outcomes in Patients With Diabetes Mellitus Treated With Versus Without Insulin + Heart Failure With Preserved Left Ventricular Ejection Fraction (from the TOPCAT Study)

We aimed to evaluate the impact of diabetes mellitus (DM) and insulin treatment on clinical outcomes in patients with heart failure and preserved left ventricular ejection fraction enrolled in the TOPCAT study. We investigated the influence of DM status (insulin-treated [ITDM], non-insulin treated [NITDM], and no diabetes [non-DM]) at baseline on time to development of the primary end point, a composite of cardiovascular (CV) mortality, heart failure hospitalization, and aborted cardiac arrest. Secondary end points included the individual components of the primary end point, myocardial infarction, stroke, all-cause mortality, hyperkalemia, and worsened renal function. Due to marked regional differences in characteristics and outcomes of the TOPCAT patients, with much lower events in patients enrolled in Russia/Georgia, we restricted our analyses on findings from patients enrolled from the Americas. Compared to patients without DM, patients with ITDM had approximately 2-fold increased risk for the primary end point, heart failure hospitalization, and myocardial infarction (hazard ratios: 1.80, 1.97, and 2.27, respectively) and approximately 50% increases in all-cause and CV mortality. The risks for these outcomes were also increased in patients with ITDM in comparison to patients with NITDM as well (hazard ratios: 1.63, 1.65, and 2.73, respectively, and approximately 40% increases in all-cause and CV mortality). Patients with NITDM had similar risks for the primary end point and all secondary end points as patients without DM. In conclusion, the apparent increased risk of adverse outcomes in patients with heart failure and preserved left ventricular ejection fraction and ITDM merits future research to improve the prognosis of these high-risk patients.

Mineralocorticoids and Cardiovascular Disease in Females with Insulin Resistance and Obesity

PURPOSE OF THE REVIEW

In the present review, we will discuss the evidence and the mechanisms underlying the complex interplay between obesity, mineralocorticoid receptor activation, and cardiovascular dysfunction with special emphasis on the pathogenesis of cardiovascular disease (CVD) in obese and insulin-resistant females.

RECENT FINDINGS

Since the initial isolation of aldosterone in 1953 and the cloning of the mineralocorticoid receptor (MR) decades later, our understanding has expanded tremendously regarding their involvement in the pathogenesis of CVD. Recent results from both pre-clinical and clinical studies support a close correlation between increase adiposity and enhanced aldosterone production (MR activation). Importantly, insulin resistance and obese females are more prone to the deleterious cardiovascular effects of MR activation, and enhanced MR activation in females has emerged as an important causative event in the genesis of a more severe CVD in diabetic women. Different clinical trials have been completed examining the effect of MR blockade in subjects with CVD. Despite its important beneficial mortality impact, side effects are frequent and a newer MR antagonist, finerenone, with less risk of hyperkalemia is currently being tested in large clinical trials.

Pharmacologic Approaches to Electrolyte Abnormalities in Heart Failure

Electrolyte abnormalities are common in heart failure and can arise from a variety of etiologies. Neurohormonal activation from ventricular dysfunction, renal dysfunction, and heart failure medications can perturb electrolyte homeostasis which impact both heart failure-related morbidity and mortality. These include disturbances in serum sodium, chloride, acid-base, and potassium homeostasis. Pharmacological treatments differ for each electrolyte abnormality and vary from older, established treatments like the vaptans or acetazolamide, to experimental or theoretical treatments like hypertonic saline or urea, or to newer, novel agents like the potassium binders: patiromer and zirconium cyclosilicate. Pharmacologic approaches range from limiting electrolyte intake or directly repleting the electrolyte, to blocking or promoting their resorption, and to neurohormonal antagonism. Because of the prevalence and clinical impact of electrolyte abnormalities, understanding both the older and newer therapeutic options is and will continue to be necessity for the management of heart failure.

Biochemical monitoring after initiation of aldosterone antagonist therapy in users of renin-angiotensin system blockers: a UK primary care cohort study

OBJECTIVE

To determine the frequency of biochemical monitoring after initiation of aldosterone antagonists(AA) in patients also using angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (ACEI/ARB).

SETTING

UK primary care.

PARTICIPANTS

ACEI/ARB users who initiated AA between 2004 and 2014.

OUTCOMES

We calculated the proportions with: (1) biochemical monitoring ≤2 weeks post initiation of AA, (2) adverse biochemical values ≤2 months (potassium ≥6 mmol/L, creatinine ≥220 µmol/L and ≥30% increase in creatinine from baseline) and (3) discontinuers of AA in those with an adverse biochemical value. We used logistic regression to study patient characteristics associated with monitoring and adverse biochemical values.

RESULTS

In 10 546 initiators of AA, 3291 (31.2%) had a record of biochemical monitoring ≤2 weeks post initiation. A total of 2.0% and 2.7% of those with follow-up monitoring within 2 months of initiation experienced potassium ≥6 mmol/L and creatinine ≥220 µmol/L, respectively, whereas 13.5% had a ≥30% increase in creatinine. Baseline potassium (OR 3.59, 95% CI 2.43 to 5.32 for 5.0-5.5 mmol/L compared with <5.0 mmol/L) and estimated glomerular filtration rate 45-59 ml/min/1.73 m² (OR 2.06, 95% CI 1.26 to 3.35 compared with ≥60 ml/min/1.73 m²) were independently predictive of potassium ≥6 mmol/L. Women and people with diabetes had higher odds of ≥30% increase in creatinine.

CONCLUSION

Less than one-third of patients taking ACEI/ARB had biochemical monitoring within 2 weeks of initiating AAs. Higher levels of monitoring may reduce adverse biochemical events.

Dilemmas in the Dosing of Heart Failure Drugs: Titrating Diuretics in Chronic Heart Failure

Despite advances in medical therapy over the past few decades, the incidence of heart failure hospitalisation continues to rise. Diuretics are the most common therapy used to treat heart failure as they relieve congestion. However, there is a lack of guidance on how to best use these medications. Guidelines support the use of diuretics at the lowest clinically effective dose but do not specify a diuretic strategy beyond that. Here we review the diuretics available for treatment, potential mechanisms of diuretic resistance and ways to address this in the ambulatory setting, and review tools that have been developed to help guide diuretic use in the treatment of chronic heart failure.

Mineralocorticoid Receptor Antagonists for Treatment of Hypertension and Heart Failure

Spironolactone and eplerenone are both mineralocorticoid-receptor antagonists. These compounds block both the epithelial and nonepithelial actions of aldosterone, with the latter assuming increasing clinical relevance. Spironolactone and eplerenone both affect reductions in blood pressure either as mono- or add-on therapy; moreover, they each afford survival benefits in diverse circumstances of heart failure and the probability of renal protection in proteinuric chronic kidney disease. However, as use of mineralocorticoid-blocking agents has expanded, the hazards inherent in taking such drugs have 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 disastrous, even fatal, if sufficient degrees of hyperkalemia emerge. For most patients, however, the risk of developing hyperkalemia in and of itself should not discourage the sensible clinician from bringing these compounds into play. Hyperkalemia should always be considered a possibility in patients receiving either of these medications; therefore, anticipatory steps should be taken to minimize the likelihood of its occurrence if long-term therapy of these agents is being considered.

Calibrating the impact of dual RAAS blockade on the heart and the kidney - balancing risks and benefits

Overactivity of the renin-angiotensin-aldosterone system (RAAS) plays a key role in the pathophysiology of heart failure (HF) and chronic kidney disease (CKD). RAAS antagonists can significantly improve clinical outcomes, but monotherapy blocks but one step of the RAAS and can be bypassed through compensatory mechanisms. Providing more complete RAAS blockade by deploying drugs with complementary actions seemed logical - hence the practice of using dual (or triple) RAAS inhibitors. However, RAAS antagonists also exhibit dose-limiting side effects, including acute kidney injury, hyperkalaemia and hypotension, which blunt their overall effectiveness. Despite achieving better RAAS blockade, several trials failed to show clinical outcome improvements. Patients with concomitant CKD and HF (cardiorenal syndrome) are at the greatest risk of these adverse events and therefore the least able to benefit, yet they also have the worst prognosis. This paradox, where those most in need have fewest therapeutic options, poses three questions which are the focus of this review: whether (i) novel therapies that prevent adverse effects can restore therapeutic benefits to patients who would otherwise be RAAS-therapy intolerant, (ii) there are any validated alternatives to their use and (iii) newer approaches to the detection of fluid congestion are ready for implementation.

Impacts of person-centred integrated chronic heart failure and palliative home care on pharmacological heart failure treatment: a substudy of a randomised trial

Objective

Patients with chronic heart failure (CHF) may be insufficiently treated pharmacologically. Recently, we presented a person-centred integrated Palliative advanced homecaRE and heart FailurE caRe (PREFER) strategy and compared it with usual care (control). Patients managed according to PREFER had improved health-related quality of life and markedly reduced hospitalisations compared with the control group. We hypothesised that these improvements may have been partly due to better drug treatments within the PREFER strategy. Thus, our aim in this study was to explore the management of drug treatments in the PREFER group compared with the control group.

Methods

Doses and numbers of drugs and the number of patients receiving the target doses based on current guidelines were measured and compared between the groups at the start and finish of the study.

Results

The percentages of ACE inhibitors (ACEIs) or mineralocorticoid receptor antagonists (MRAs) increased, while loop diuretics decreased in the PREFER arm during the study, although the differences were not significant. Beta-receptor blockers (BBs) decreased somewhat in both groups. The number of patients treated with MRAs differed the most between groups, and increased from 10 (28%) to 15 (48%) in the PREFER arm compared with 13 (35%) vs 13 (39%) in the control group. The change in patients receiving full target doses (+8 vs. +1) of the ACEIs/angiotensin receptor blockers, BBs and MRAs were significantly higher (p=0009) in the PREFER arm than in the control arm.

Conclusions

Person-centred integrated care of patients with severe CHF was associated with increased evidence-based drug treatments, especially MRAs.

Clinical trial number

NCT01304381.

Facility variation and predictors of serum potassium monitoring after initiation of a mineralocorticoid receptor antagonist in patients with heart failure

BACKGROUND

Mineralocorticoid receptor antagonists (MRAs) have been shown to reduce morbidity and mortality in patients with heart failure (HF) with reduced ejection fraction but are associated with hyperkalemia. We sought to evaluate the frequency, variation, and predictors associated with serum potassium monitoring in patients with HF initiated on an MRA among facilities in the Veterans Affairs (VA) Health Care System.

METHODS

We performed a retrospective cohort analysis of patients with HF across 133 Veterans Affairs facilities from 2003 to 2013 who were given a new prescription of an MRA. The primary outcome was the mean percentage of patients per facility with serum potassium monitoring within 14 days of MRA dispensing. Univariate and covariate analyses were performed to determine factors associated with monitoring.

RESULTS

There were 142,880 patients identified with HF initiated on an MRA who met the study inclusion and exclusion criteria. The mean (SD) percentage of patients per facility with serum potassium monitoring within 14 days was 41.6% (standard deviation 8.0%; minimum 18.9%, maximum 56.7%). Facilities with a higher frequency of monitoring were associated with membership in the Council on Teaching Hospitals (n = 70, P < .0001), had academic affiliations (n = 100, P < .0001), and a higher annual volume of patients with HF (≥200 patients, P < .0001).

CONCLUSIONS

In a large multicenter national sample of patients with HF receiving a new MRA prescription, the frequency of serum potassium monitoring was below recommended guidelines. Academic facilities and those with a higher volume of patients with HF were associated with an increased frequency of monitoring.

What Physicians Need to Know About Renal Function in Outpatients with Heart Failure

The majority of outpatients with heart failure (HF) have chronic kidney disease (CKD) as an important comorbidity. Both glomerular filtration rate and abnormal urinary albumin excretion are major predictors of outcome in HF patients. Despite this, patients with renal dysfunction have been systematically excluded from the large randomized HF trials. There is lack of evidence for optimal treatment in these cardiorenal patients and treatment nihilism may account in part for their bad prognosis. Identifying and monitoring the progression of renal disease and making an effort to preserve renal function should be an important task in the management of all patients with HF. In this review, the current understanding of the pathophysiology of renal dysfunction in outpatients with HF will be summarized. Furthermore, important principles of the identification and management of cardiorenal patients will be described in order to make the physician more capable of managing outpatients with HF and renal dysfunction.

Risk of hyperkalemia and combined use of spironolactone and long-term ACE inhibitor/angiotensin receptor blocker therapy in heart failure using real-life data: a population- and insurance-based cohort

PURPOSE

Clinical trials and few observational studies report increased hyperkalemia risks in heart failure patients receiving aldosterone blockers in addition to standard therapy. The aim of this study is to assess the hyperkalemia risk and combined use of spironolactone and long-term ACE (angiotensin-converting enzyme) inhibitor/angiotensin receptor blocker (ARB) therapy for heart failure in a real-life setting of a heterogeneous population.

METHODS

Using claims data of the statutory health insurance fund AOK, covering 30% of the German population, we performed a nested case-control study in a cohort of heart failure patients receiving continuous ACE/ARB therapy (n = 1,491,894). Hyperkalemia risk associated with concurrent use of spironolactone and ACE/ARB was calculated by conditional logistic regression in 1062 cases and 10,620 risk-set-sampling-matched controls.

RESULTS

Risk of hyperkalemia in heart failure patients was significantly associated with spironolactone use (odds ratio (OR) (95% confidence interval (CI)) = 13.59 (11.63-15.88) in all and 11.05 (8.67-14.08) in those with information on New York Heart Association (NYHA) stage of disease). In the NYHA subpopulation, higher risk estimates were observed in short-term as compared with long-term users (OR (95%CI) = 13.00 (9.82-17.21) and 9.12 (6.78-12.26), respectively). Moreover, the association was stronger in older (≥70 years of age) as compared with younger patients (<70 years of age) (OR (95%CI) = 12.32 (9.35-16.23) and 8.73 (5.05-15.08), respectively), although interaction was not significant (pinteraction  = 0.07).

CONCLUSIONS

Hyperkalemia risk associated with combined use of spironolactone and ACE/ARB is much stronger in real-life practice than observed in clinical trials. Careful potassium level monitoring in concomitant users of spironolactone and ACE/ARB is necessary.

Characterization of structure and function of ZS-9, a K+ selective ion trap

Hyperkalemia, a condition in which serum potassium ions (K+) exceed 5.0 mmol/L, is a common electrolyte disorder associated with substantial morbidity. Current methods of managing hyperkalemia, including organic polymer resins such as sodium polystyrene sulfonate (SPS), are poorly tolerated and/or not effective. Sodium zirconium cyclosilicate (ZS-9) is under clinical development as an orally administered, non-absorbed, novel, inorganic microporous zirconium silicate compound that selectively removes excess K+ in vivo. The development, structure and ion exchange properties of ZS-9 and its hypothesized mechanism of action are described. Based on calculation of the interatomic distances between the atoms forming the ZS-9 micropores, the size of the pore opening was determined to be ∼ 3 Å (∼ diameter of unhydrated K+). Unlike nonspecific organic polymer resins like SPS, the ZS-9 K+ exchange capacity (KEC) was unaffected by the presence of calcium (Ca2+) or magnesium ions (Mg2+) and showed>25-fold selectivity for K+ over either Ca2+ or Mg2+. Conversely, the selectivity of SPS for K+ was only 0.2-0.3 times its selectivity for Ca2+ or Mg2+in mixed ionic media. It is hypothesized that the high K+ specificity of ZS-9 is attributable to the chemical composition and diameter of the micropores, which possibly act in an analogous manner to the selectivity filter utilized by physiologic K+ channels. This hypothesized mechanism of action is supported by the multi-ion exchange studies. The effect of pH on the KEC of ZS-9 was tested in different media buffered to mimic different portions of the human gastrointestinal tract. Rapid K+ uptake was observed within 5 minutes - mainly in the simulated small intestinal and large intestinal fluids, an effect that was sustained for up to 1 hour. If approved, ZS-9 will represent a novel, first-in-class therapy for hyperkalemia with improved capacity, selectivity, and speed for entrapping K+ when compared to currently available options.

Converging indications of aldosterone antagonists (spironolactone and eplerenone): a narrative review of safety profiles

The converging clinical effectiveness of mineralocorticoid receptor antagonists (MRAs) Spironolactone and Eplerenone has made their safety profiles/cost-effectiveness key determinants of "agents of choice" across a broad range of clinical indications. The clinical biology of the aldosterone molecule and its range of effects in varied organ systems have been well elucidated from recent mechanistic and systematic studies. Clinical experience with Spironolactone is well established, as is its adverse effects profile. The range of adverse effects experienced with Spironolactone subsequently led to its modification and synthesis of Eplerenone. Recent published reports have confirmed lower prevalence rates of sex-related adverse effects attributable to Eplerenone compared to Spironolactone. There is, however, not much to choose between these agents in regards to other adverse effects including hyperkalemia and kidney failure. As was the experience with Spironolactone, as more robust observational data on Eplerenone accrues, it is possible that the real-life experience of its adverse profile may be discordant with that reported by randomized controlled clinical trials (RCTs). In addition, its metabolism by the vulnerable and highly polymorphic cytochrome dependent pathway also makes it susceptible to various drug interactions. The potential implication of the latter (including morbidity and mortality) may take years to evolve.

Mechanisms of renal control of potassium homeostasis in complete aldosterone deficiency

Aldosterone-independent mechanisms may contribute to K(+) homeostasis. We studied aldosterone synthase knockout (AS(-/-)) mice to define renal control mechanisms of K(+) homeostasis in complete aldosterone deficiency. AS(-/-) mice were normokalemic and tolerated a physiologic dietary K(+) load (2% K(+), 2 days) without signs of illness, except some degree of polyuria. With supraphysiologic K(+) intake (5% K(+)), AS(-/-) mice decompensated and became hyperkalemic. High-K(+) diets induced upregulation of the renal outer medullary K(+) channel in AS(-/-) mice, whereas upregulation of the epithelial sodium channel (ENaC) sufficient to increase the electrochemical driving force for K(+) excretion was detected only with a 2% K(+) diet. Phosphorylation of the thiazide-sensitive NaCl cotransporter was consistently lower in AS(-/-) mice than in AS(+/+) mice and was downregulated in mice of both genotypes in response to increased K(+) intake. Inhibition of the angiotensin II type 1 receptor reduced renal creatinine clearance and apical ENaC localization, and caused severe hyperkalemia in AS(-/-) mice. In contrast with the kidney, the distal colon of AS(-/-) mice did not respond to dietary K(+) loading, as indicated by Ussing-type chamber experiments. Thus, renal adaptation to a physiologic, but not supraphysiologic, K(+) load can be achieved in aldosterone deficiency by aldosterone-independent activation of the renal outer medullary K(+) channel and ENaC, to which angiotensin II may contribute. Enhanced urinary flow and reduced activity of the thiazide-sensitive NaCl cotransporter may support renal adaptation by activation of flow-dependent K(+) secretion and increased intratubular availability of Na(+) that can be reabsorbed in exchange for K(+) secreted.

Spironolactone use and higher hospital readmission for Medicare beneficiaries with heart failure, left ventricular ejection fraction <45%, and estimated glomerular filtration rate <45 ml/min/1.73 m(2.)

Although randomized controlled trials have demonstrated benefits of aldosterone antagonists for patients with heart failure and reduced ejection fraction (HFrEF), they excluded patients with serum creatinine >2.5 mg/dl, and their use is contraindicated in those with advanced chronic kidney disease (CKD). In the present analysis, we examined the association of spironolactone use with readmission in hospitalized Medicare beneficiaries with HFrEF and advanced CKD. Of the 1,140 patients with HFrEF (EF <45%) and advanced CKD (estimated glomerular filtration rate [eGFR] <45 ml/min/1.73 m(2)), 207 received discharge prescriptions for spironolactone. Using propensity scores (PSs) for the receipt of discharge prescriptions for spironolactone, we estimated PS-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for spironolactone-associated outcomes. Patients (mean age 76 years, 49% women, 25% African-American) had mean EF 28%, mean eGFR 31 ml/min/1.73 m(2), and mean potassium 4.5 mEq/L. Spironolactone use had significant PS-adjusted association with higher risk of 30-day (HR 1.41, 95% CI 1.04 to 1.90) and 1-year (HR 1.36, 95% CI 1.13 to 1.63) all-cause readmissions. The risk of 1-year all-cause readmission was higher among 106 patients with eGFR <15 ml/min/1.73 m(2) (HR 4.75, 95% CI 1.84 to 12.28) than among those with eGFR 15 to 45 ml/min/1.73 m(2) (HR 1.34, 95% CI 1.11 to 1.61, p for interaction 0.003). Spironolactone use had no association with HF readmission and all-cause mortality. In conclusion, among hospitalized patients with HFrEF and advanced CKD, spironolactone use was associated with higher all-cause readmission but had no association with all-cause mortality or HF readmission.

Endocrine and hypertensive disorders of potassium regulation: primary aldosteronism

The identification of primary aldosteronism as a common cause of resistant hypertension is a significant advance in our ability to care for patients with hypertension. Primary aldosteronism is common, and when unrecognized is associated with an increased incidence of adverse cardiovascular outcomes. Identification of primary aldosteronism is based on use of the plasma aldosterone level, plasma renin activity, and the aldosterone:renin ratio. Differentiation between unilateral and bilateral autonomous adrenal aldosterone production then guides further therapy, with use of mineralocorticoid-receptor blockers for patients with bilateral autonomous adrenal aldosterone production and laparoscopic adrenalectomy for patients with unilateral autonomous aldosterone production. In this review, we discuss in detail the pathogenesis of primary aldosteronism-induced hypertension and potassium disorders, the evaluation of the patient with suspected primary aldosteronism, and the management of primary aldosteronism, both through medications and surgery.

The cardiorenal syndrome: what the cardiologist needs to know

Interactions between the heart and the kidneys are increasingly acknowledged among both cardiologists and nephrologists. The term cardiorenal syndrome now applies to the bidirectional nature of how disease in one organ system affects the function of the other organ system. Cardiovascular disease is a major threat to patients with chronic kidney disease, while renal dysfunction is prevalent in patients with cardiac disease and is a significant predictor of prognosis in cardiac patients. Still, renal patients with cardiac disease have largely been excluded from the clinical trials that have been the basis of modern cardiologic treatment. In this review, the current understanding of the pathophysiological mechanisms involved in the cardiorenal syndrome and potential therapeutic implications will be summarized from a nephrologist's point of view. Probably, fragile cardiorenal patients will benefit from an enhanced collaboration between cardiologists and nephrologists to secure the best treatment given under safe conditions.

Heart failure in elderly: progress in clinical evaluation and therapeutic approach

Chronic heart failure (CHF) represents a major and growing health problem, due to its high incidence and prevalence, its poor prognosis and its impact on health-care costs. Although CHF patients are mainly elderly, few studies were aimed at testing the efficacy of diagnostic and therapeutic approaches in this population. The difficulty in CHF diagnosis among the elderly is related to different factors, such as: the frequent presence of co-morbidity conditions mimicking or masking heart failure signs and symptoms; the different diagnostic cut-offs of natriuretic peptides; and the need to correctly evaluate diastolic function in order to assess CHF with preserved ejection fraction. Furthermore, the therapy of elderly CHF patients has not been well defined, considering the few studies involving very aged patients and the absence of a therapeutic strategy demonstrated to improve prognosis of CHF patients with preserved ejection fraction. The aim of this review is to focus on the most recent issues concerning the diagnosis and therapy of elderly patients affected by CHF.

Safety of spironolactone in dogs with chronic heart failure because of degenerative valvular disease: a population-based, longitudinal study

BACKGROUND

Spironolactone treatment in humans is associated with an increased risk of hyperkalemia and renal dysfunction.

HYPOTHESIS

Dogs with cardiac disease treated with spironolactone, in addition to conventional therapy, are not at higher risk for adverse events (AEs) than those receiving solely conventional therapy.

ANIMALS

One hundred and ninety-six client-owned dogs with naturally occurring myxomatous mitral valve disease.

METHODS

Prospective, double-blinded field study with dogs randomized to receive either spironolactone (2 mg/kg once a day) or placebo in addition to conventional therapy (angiotensin-converting enzyme inhibitor, plus furosemide and digoxin if needed). Safety was compared between treatment groups, using the frequency of AEs, death caused by cardiac disease, renal disease, or both, and variations in serum sodium, potassium, urea, and creatinine concentrations. For the latter, population-specific reference intervals were established and out of range values (ORV) analyzed.

RESULTS

The number of AEs was similar in the spironolactone and reference groups (188 and 208, respectively), when followed for median duration of 217 days (range [2-1,333]). At each study time point, the percentage of dogs showing ORV was similar between groups. There were a higher number of deaths because of cardiac disease, renal disease or both in the reference group (30.7% versus 13.7%) (P = .0043).

CONCLUSIONS AND CLINICAL IMPORTANCE

Dogs with heart failure receiving spironolactone in addition to conventional treatment are not at a higher risk for AEs, death caused by cardiac disease, renal disease, or both, hyperkalemia, or azotemia.

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.

Pharmacotherapy of heart failure in the elderly: adverse events

Aging is associated with numerous alterations in body composition and organ function that result in substantial changes in the absorption, distribution, metabolism, and elimination of virtually all drugs. In addition, older patients with heart failure (HF) almost invariably have multiple coexisting medical conditions for which they are receiving medications. This article reviews common adverse drug effects and drug interactions associated with HF therapy in older patients and discusses strategies for reducing the risk of adverse drug events. In order to minimize these risks, it is essential that clinicians avoid prescribing unnecessary medications, adjust medication dosages to optimally balance benefits and side effects, and remain ever vigilant to the potential for medications to cause or contribute to clinically important adverse events and impaired quality of life. In treating older HF patients, the oft-cited dictum "start low, go slow" clearly applies. Despite the inherent challenges, with careful management and close follow-up, most older HF patients can be successfully treated through the judicious use of guideline-recommended HF therapies.

Association of spironolactone use with all-cause mortality in heart failure: a propensity scored cohort study

BACKGROUND

In 3 randomized controlled trials in heart failure (HF), mineralocorticoid receptor antagonists reduced mortality. The net benefit from randomized controlled trials may not be generalizable, and eplerenone was, but spironolactone was not, studied in mild HF. We tested the hypothesis that spironolactone is associated with reduced mortality also in a broad unselected contemporary population with HF and reduced ejection fraction, in particular New York Heart Association (NYHA) I-II.

METHODS AND RESULTS

We prospectively studied 18 852 patients (age 71±12 years; 28% women) with NYHA I-IV and ejection fraction <40% who were registered in the Swedish Heart Failure Registry between 2000 and 2012 and who were (n=6551) or were not (n=12 301) treated with spironolactone. We derived propensity scores for spironolactone treatment based on 41 covariates. We assessed survival by Cox regression with adjustment for propensity scores and with matching based on propensity score. We performed sensitivity and residual confounding analyses and analyzed the NYHA I-II and III-IV subgroups separately. One-year survival was 83% versus 84% in treated versus untreated patients (log rank P<0.001). After adjustment for propensity scores, the hazard ratio for spironolactone was 1.05 (95% confidence interval, 1.00-1.11; P=0.054). Spironolactone interacted with NYHA (P<0.001). In the NYHA I-II subgroup, after adjustment for propensity scores, the hazard ratio for spironolactone was 1.11 (95% confidence interval, 1.02-1.21; P=0.019).

CONCLUSIONS

In an unselected contemporary population of HF with reduced ejection fraction, spironolactone was not associated with reduced mortality. The net benefits of spironolactone may be lower outside the clinical trial setting and in milder HF.

Current strategies for preventing renal dysfunction in patients with heart failure: a heart failure stage approach

Renal dysfunction is common during episodes of acute decompensated heart failure, and historical data indicate that the mean creatinine level at admission has risen in recent decades. Different mechanisms underlying this change over time have been proposed, such as demographic changes, hemodynamic and neurohumoral derangements and medical interventions. In this setting, various strategies have been proposed for the prevention of renal dysfunction with heterogeneous results. In the present article, we review and discuss the main aspects of renal dysfunction prevention according to the different stages of heart failure.

Hyperkalaemia in the age of aldosterone antagonism

Hyperkalaemia is well recognized as a medical emergency. However, with the publication of trials showing benefit with renin-aldosterone axis suppression in heart failure, the epidemiology of patients presenting with hyperkalaemia has changed. The reported incidence of rate of serious hyperkalaemia (>6.0 mEq/l of potassium) ranges from 6 to 12% in patients on spironolactone with congestive cardiac failure (CCF). A rational choice of therapy based on present evidence is different from the traditionally used algorithm, given our understanding of the physiology relevant to this patient group. This article discusses the changing face of hyperkalaemia and the present evidence and discusses options in treatment of hyperkalaemia.

Mineralocorticoid receptor activation in myocardial infarction and failure: recent advances

The classical view of aldosterone actions via the mineralocorticoid receptor (MR) limited to control of fluid balance and blood pressure homoeostasis has been progressively overcome by clinical and experimental evidence emphasizing the pleiotropic role of MR activation in the pathogenesis of cardiovascular disease. Clinical studies have shown the benefit of MR blockade in patients with left ventricular dysfunction and heart failure after myocardial infarction (MI), hypertension or diabetic nephropathy. Deleterious effects of MR activation include cardiac structural and electrical remodelling, cardiovascular fibrosis, inflammation and oxidative stress. Complexity of pathophysiological role of MR derives from the presence of circulating glucocorticoids at higher concentrations than aldosterone and the equal affinity of the MR for aldosterone, cortisol and corticosterone. Recent experimental studies using different animal models and genetic tools have deeply explored the cell-specific functional role of MR in cardiovascular pathology. This review addresses emerging preclinical studies as well as ongoing clinical trials regarding MR activation in MI and failure.

Frequency and predictors of hyperkalemia in patients ≥60 years of age with heart failure undergoing intense medical therapy

Hyperkalemia is a concern in heart failure (HF), especially in older patients with co-morbidities. Previous studies addressing this issue have focused mainly on younger patients. This study was aimed at determining the frequency and predictors of hyperkalemia in older patients with HF undergoing intense medical therapy. Frequency and predictors of hyperkalemia were defined in patients (n = 566) participating in the Trial of Intensified versus Standard Medical Therapy in Elderly Patients with Congestive Heart Failure, in which patients ≥60 years of age were randomized to a standard versus an intensified N-terminal brain natriuretic peptide-guided HF therapy. During an 18-month follow-up 76 patients (13.4%) had hyperkalemia (≥5.5 mmol/L) and 28 (4.9%) had severe hyperkalemia (≥6.0 mmol/L). Higher baseline serum potassium (odds ratio [OR] 2.92 per mmol/L), baseline creatinine (OR 1.11 per 10 μmol/L), gout (OR 2.56), New York Heart Association (NYHA) class (compared to NYHA class II, IV OR 3.08), higher dosage of spironolactone at baseline (OR 1.20 per 12.5 mg/day), and higher dose changes of spironolactone (compared to no dose change: 12.5 mg, OR 1.45; 25 mg, OR 2.52; >25 mg, OR 3.24) were independent predictors for development of hyperkalemia (p <0.05 for all comparisons). In conclusion, hyperkalemia is common in patients ≥60 years of age with HF undergoing intense medical therapy. Risk is increased in patients treated with spironolactone, in addition to patient-specific risk factors such as chronic kidney disease, higher serum potassium, advanced NYHA class, and gout. Careful surveillance of serum potassium and cautious use of spironolactone in patients at risk may help to decrease the incidence of potentially hazardous complications caused by hyperkalemia.

Appropriateness and complications of the use of spironolactone in patients treated in a heart failure clinic

OBJECTIVES

The widespread use of spironolactone in patients with congestive heart failure (CHF) has resulted in side effects and complications. We analyzed a cohort of patients treated by a dedicated CHF team, in order to examine the tolerability and safety of spironolactone in clinical practice.

METHODS

We retrospectively evaluated data on 157 patients who were followed by the Heart Failure clinic of whom 100 patients on maximal treatment (all on β blockers, 99% on ACE inhibitors) received spironolactone. The complications following spironolactone use were defined as: hyperkalemia with serum K 5.2 mEq/l; creatinine 2.0 mg/dl; hyponatremia with serum Na 135 mEq/l, hypotension and side effects such as gynecomastia and abdominal pain.

RESULTS

At 1 year follow-up 6 patients developed hyperkalemia (range 5.3-5.9), 4 of them had K>5.5 mEq/l. Two patients developed hyponatremia. Six patients stopped spironolactone for: 1-gynecomastia, 2-worsening renal failure and hyperkalemia, 2-hyperkalemia (5.9 mEq/l) and 1 for bradycardia. There was an increase in mean creatinine level at 1 year (1.12±0.35 vs. 1.21±0.38 mg/dl, p=0.02), however, no significant changes were found in GFR (99.9±33.5 vs. 65.7±27.7 ml min(-1)1.73 m(-2), p=ns) and potassium (4.5±0.4 vs. 4.6±0.5 mEq/l, p=ns). We found improvement of GFR by >10% in 19 patients and worsening by >10% in 38 patients. No patient was hospitalized or required urgent treatment for spironolactone-related side effects.

CONCLUSIONS

In patients with CHF on optimal therapy with ACE inhibitors and β blockers appropriate spironolactone use and close follow-up by a dedicated HF team can minimize the risk for adverse events and complications.

What is the risk of hyperkalaemia in heart failure?

INTRODUCTION

Chronic heart failure (CHF) is the only major cardiovascular disease whose prevalence and incidence are thought to be increasing. Potassium balance may be lost both through the neurohormonal mechanisms involved in cardiovascular diseases and through the drugs used in their treatment. Avoiding both hypo- and hyperkalemia is difficult but beneficial in CHF.

AREAS COVERED

Aldosterone production is decreased in the elderly, diabetic patients, and those receiving drugs that block the production or action of renin and angiotensin II. As a result, these groups, as well as those with already impaired potassium excretion due to progressive age or disease-related decline in glomerular filtration rate, are particularly vulnerable to the development of hyperkalemia.

EXPERT OPINION

Evidence from several studies suggests that, in patients with CHF, serum potassium should be maintained between 4.0 and 5.5 mEq/L. To gain the maximum benefit from aldosterone antagonists it is necessary to individualize their use; it is also necessary to carefully monitor electrolytes.