Potassium and the use of renin-angiotensin-aldosterone system inhibitors in heart failure with reduced ejection fraction: data from BIOSTAT-CHF

Epidemiology and risk factors for hyperkalaemia in heart failure

Patients with heart failure (HF), particularly those with impaired renal function receiving renin-angiotensin-aldosterone system inhibitors (RAASis), are at risk of hyperkalaemia; when hyperkalaemia is severe, this can have serious clinical consequences. The incidence, prevalence, and risk factors for hyperkalaemia reported in randomized trials of RAASis may not reflect clinical practice due to exclusion of patients with elevated serum potassium (sK+) or severe renal impairment: information on patients managed in routine clinical care is important to understanding the actual burden of hyperkalaemia. This paper reviews the available clinical epidemiology data on hyperkalaemia in HF and considers areas requiring further research. Observational studies published since 2017 that focused on hyperkalaemia, included patients with HF, and had ≥1000 participants were considered. Hyperkalaemia occurrence in HF varied widely from 7% to 39% depending on the setting, HF severity, follow-up length, and concomitant medications. Rates were lowest in patients with newly diagnosed HF and highest in patients with greater disease severity; comorbidities, such as chronic kidney disease and diabetes, and RAASi use, reflected commonly identified risk factors for hyperkalaemia in patients with HF. Hyperkalaemia was most often mild; however, from the limited data available, persistence of mild hyperkalaemia was associated with an increased risk of mortality and major adverse cardiovascular events. There were also limited data available on the progression of hyperkalaemia. Recurrence was common, occurring in one-quarter to two-fifths of hyperkalaemia cases. Despite HF guidelines recommending close monitoring of sK+, 55-93% of patients did not receive appropriate testing before or after initiation of RAASi or in follow-up to moderate/severe hyperkalaemia detection. Many of the observational studies were retrospective and from a single country. There is a need for international, prospective, longitudinal, observational studies, such as the CARE-HK in HF study (NCT04864795), to understand hyperkalaemia's prevalence, incidence, and severity; to identify and characterize cases that persist, progress, and recur; to highlight the importance of sK+ monitoring when using RAASi; and to assess the impact of newer HF therapies and potassium binders in clinical practice. Data from both clinical trials and observational studies with adjustments for confounding variables will be needed to assess the contribution of hyperkalaemia to clinical outcomes.

The Efficacy and Safety of Patiromer for Heart Failure Patients: A Systematic Review and Meta-Analysis

PURPOSE

To evaluate the efficacy and safety of patiromer, a novel potassium binder, in reducing the risk of hyperkalemia in patients with heart failure and optimizing their RAASi therapy.

DESIGN

Systematic review and meta-analyses.

METHOD

The authors conducted a systematic search in Pubmed, Embase, Web of Science, and Cochrane Library for randomized controlled trials investigating the efficacy and safety of patiromer in heart failure patients from inception to 31 January 2023 and updated on 25 March 2023. The primary outcome was the association between the reduction of hyperkalemia and patiromer compared with placebo, and the secondary outcome was the association between optimization of RAASi therapy and patiromer.

RESULTS

A total of four randomized controlled trials (n = 1163) were included in the study. Patiromer was able to reduce the risk of hyperkalemia in heart failure patients by 44% (RR 0.56, 95% CI 0.36 to 0.87; I² = 61.9%), improve tolerance to target doses of MRA in patients with heart failure (RR 1.15, 95% CI 1.02 to 1.30; I² = 49.4%), and decrease the proportion of all-cause discontinuation of RAASi (RR 0.49, 95% CI 0.25 to 0.98; I² = 48.4%). However, patiromer therapy was associated with an increased risk of hypokalemia (RR 1.51, 95% CI 1.07 to 2.12; I² = 0%), while no other statistically significant adverse events were observed.

CONCLUSION

Patiromer appears to have a considerable effect on reducing the incidence of hyperkalemia in heart failure patients and on optimizing the therapy of RAASi in those patients.

Impact of Hyperkalemia in Heart Failure and Reduced Ejection Fraction: A Retrospective Study

(1) Background: Hyperkalemia is a common finding in patients with heart failure and reduced ejection fraction (HFrEF), though its prognostic significance is controversial. There is no consensus on optimal potassium levels in these patients. The primary endpoint of this study was to determine the 5-year incidence of hyperkalemia in a cohort of patients with HFrEF. Secondary endpoints were to determine predictors of hyperkalemia and its impact on overall 5-year mortality; (2) Methods: retrospective, longitudinal, single-center observational study of patients with HFrEF followed-up in a specialized unit between 2011 and 2019. Hyperkalemia was considered as potassium concentration > 5.5 mEq/L; (3) Results: Hyperkalemia was observed in 170 (16.8%) of the 1013 patients. The 5-year hyperkalemia-free survival rate was 82.1%. Hyperkalemia was more frequent at the beginning of follow-up. Factors associated with hyperkalemia in the multivariate analysis were baseline potassium (HR 3.13, 95%CI 2.15-4.60; p < 0.001), creatinine clearance (HR 0.99, 95%CI 0.98-0.99; p = 0.013), right ventricular function (HR 0.95, 95%CI 0.91-0.99; p = 0.016) and diabetes mellitus (HR 1.40, 95%CI 1.01-1.96; p = 0.047). The overall survival rate at 5 years was 76.4%. Normal-high potassium levels (5-5.5 mEq/L) were inversely associated with mortality (HR 0.60, 95%CI 0.38-0.94; p = 0.025); (4) Conclusions: Hyperkalemia is a common finding in patients with HFrEF with an impact on the optimization of neurohormonal treatment. In our retrospective study, potassium levels in the normal-high range seem to be safe and are not associated with increased mortality.

Safety and efficacy of new potassium binders on hyperkalemia management in patients with heart failure: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Hyperkalemia leads to suboptimal use of evidence-based therapies in patients with heart failure (HF). Therefore, we aimed to assess whether new potassium binders are effective and safe to promote medical optimization in patients with HF.

METHODS

MEDLINE, Cochrane, and Embase were searched for randomized controlled trials (RCTs) that reported outcomes after initiation of Patiromer or Sodium Zirconium Cyclosilicate (SZC) versus placebo in patients with HF at high risk of hyperkalemia development. Risk ratios (RR) with 95% confidence intervals (CI) were pooled with a random effects model. Quality assessment and risk of bias were performed according to Cochrane recommendations.

RESULTS

A total of 1432 patients from 6 RCTs were included, of whom 737 (51.5%) patients received potassium binders. In patients with HF, potassium binders increased the use of renin-angiotensin-aldosterone inhibitors (RR 1.14; 95% CI 1.02-1.28; p = 0.021; I² = 44%) and reduced the risk of hyperkalemia (RR 0.66; 95% CI 0.52-0.84; p < 0.001; I² = 46%). The risk of hypokalemia was significantly increased in patients treated with potassium binders (RR 5.61; 95% CI 1.49-21.08; p = 0.011; I² = 0%). There was no difference between groups in all-cause mortality rates (RR 1.13; 95% CI 0.59-2.16; p = 0.721; I² = 0%) or in adverse events leading to drug discontinuation (RR 1.08; 95% CI 0.60-1.93; p = 0.801; I² = 0%).

CONCLUSION

The use of new potassium binders Patiromer or SZC in patients with HF at risk for hyperkalemia increased the rates of medical therapy optimization with renin-angiotensin-aldosterone inhibitors and reduced the incidence of hyperkalemia, at the cost of an increased prevalence of hypokalemia.

High- Versus Low-dose Losartan and Serum Potassium: An Analysis From HEAAL

BACKGROUND

Patients with heart failure (HF) experience frequent alterations of serum potassium. Despite the high risk of events associated with hypokalemia, hyperkalemia is feared by clinicians and often leads to interruption or discontinuation of renin-angiotensin-aldosterone system inhibitors. Data on serum potassium of patients treated with different doses of renin-angiotensin-aldosterone system inhibitors are scarce.

METHODS AND RESULTS

The effects of high-dose vs low-dose losartan on clinical outcomes in patients with heart failure (HEAAL) trial randomized 3834 patients with HFrEF intolerant to angiotensin-converting enzyme inhibitors to losartan 150 mg/d (high dose) vs 50 mg/d (low dose). We studied the associations of serum potassium (baseline and time updated) with study outcomes and the effect of the randomized treatment on serum potassium. Patients with higher baseline potassium were older, had diabetes, poorer renal function, and used mineralocorticoid receptor antagonists more frequently. In time-updated models, hyperkalemia (>5.0 or ≥5.5 mmol/L) was not associated with cardiovascular death or the composite of cardiovascular death or HF hospitalization. Hypokalemia (serum potassium of ≤3.5 mmol/L, in particular) was associated with a higher risk of the composite of cardiovascular death or HF hospitalization (hazard ratio [HR] 1.58, 95% confidence interval [CI] 1.19-2.08), all-cause death (HR 1.68, 95% CI 1.26-2.24), and sudden cardiac death or resuscitated cardiac arrest (HR 1.74, 95% CI 1.11-2.73). High-dose losartan decreased the risk of hypokalemia (HR 0.77, 95% CI 0.63-0.92) and increased the risk of hyperkalemia (HR 1.21, 95% CI 1.05-1.39). High-dose losartan decreased the composite of cardiovascular death or HF hospitalizations consistently across the full spectrum of serum potassium at baseline (interaction P = .85).

CONCLUSIONS

In patients with HF with reduced ejection fraction intolerant to angiotensin-converting enzyme inhibitors and treated with either high- or low-dose losartan, incident hypokalemia had a stronger association with poor outcomes than incident hyperkalemia. High-dose losartan reduced the incidence of hypokalemia, and its benefits were maintained across the full spectrum of serum potassium.

Association of Potassium Level at Discharge with Long-Term Mortality in Hospitalized Patients with Heart Failure

Dyskalemia (hypokalemia and hyperkalemia) is a common comorbidity of heart failure (HF). Although dyskalemia is associated with poor prognosis, different prognostic impacts of hypo- and hyperkalemia remain vastly unclear. This study investigated the association of dyskalemia with prognosis in HF patients, especially the mode of death and left ventricular ejection fraction (LVEF). The multicenter study included 3398 patients hospitalized for HF. Patients were divided into three groups based on serum potassium levels at discharge: hypokalemia (<3.5 mEq/L; n = 115 (3.4%)), normokalemia (3.5−5.0 mEq/L; n = 2960 (87.1%)), and hyperkalemia (≥5.0 mEq/L; n = 323 (9.5%)). Two-year all-cause, cardiac, and non-cardiac mortality was evaluated. Association of serum potassium with two-year mortality demonstrated a U-shaped curve, with a worse prognosis for patients with hypokalemia. All-cause mortality at two-years did not differ among the three groups. Hypokalemia was associated with 2-year cardiac death (adjusted hazard ratio (HR), 2.60; 95% confidence interval (CI), 1.20−5.64) in HF with reduced ejection fraction (HFrEF; LVEF < 40%), but not in non-HFrEF. Regardless of LVEF, hyperkalemia was not independently associated with any mortality. Hypokalemia was independently associated with cardiac death, particularly in HFrEF patients. Such an association was not observed in hyperkalemia regardless of LVEF.

Frequency and predictors of hyperkalemia in the heart failure outpatient clinic

Objectives: Hyperkalemia is a common and life-threatening condition affecting heart failure (HF) patients. This study aims to show the frequency of hyperkalemia and related factors in the HF outpatient clinic in real world data. Methods: 1146 patients monitored in the HF outpatient clinic with left ventricular ejection fraction ≤ 40% and potassium level ≥ 3.5 mmol/L were included in the study. Results: The median potassium value of the patients was 4.6 [IQR, 4.3-5] mmol/L. It was evaluated in three groups as 3.5-5 mmol/L (normokalaemia), 5.1-5.5 mmol/L (mild hyperkalemia), and ≥ 5.5 mmol/L (moderate to severe hyperkalemia) according to baseline potassium levels. 14.5% of patients had mild hyperkalemia and 7.1% had moderate to severe hyperkalemia. Patients with a potassium value of > 5 mmol/L made up 21.6%. The estimated glomerular filtration rate (eGFR) (OR: 0.968, 95% CI: 0.959-0.977, p

Motives, frequency, predictors and outcomes of MRA discontinuation in a real-world heart failure population

INTRODUCTION

Mineralocorticoid receptor antagonists (MRAs) reduce mortality and morbidity in patients with heart failure and reduced ejection fraction (HFrEF), but are largely underused. We evaluated the frequency, motives, predictors and outcomes of MRA discontinuation in a real-world heart failure population.

METHODS AND RESULTS

This was a single-centre, retrospective cohort study where medical record-based data were collected on patients with HFrEF between 2010 and 2018. In the final analysis, 572 patients were included that comprised the continued MRA group (n=275) and the discontinued MRA group (n=297). Patients that discontinued MRA were older, had a higher comorbidity index and a lower index estimated glomerular filtration rate (eGFR). Predictors of MRA discontinuations were increased S-potassium, lower eGFR, lower systolic blood pressure, higher frequency of comorbidities and a higher left ventricular ejection fraction. The most common reason for MRA discontinuation was renal dysfunction (n=97, 33%) with 59% of these having an eGFR <30 mL/min/1.73m², and elevated S-potassium (n=71, 24%) with 32% of these having an S-potassium >5.5 mmol/L. Discontinuation of MRA increased the adjusted risk of all-cause mortality (HR 1.48; 95% CI 1.07 to 2.05; p=0.019).

CONCLUSIONS

Half of all patients with HFrEF initiated on MRA discontinued the treatment. A substantial number of patients discontinued MRA without meeting the guideline-recommended levels of eGFR and S-potassium where mild to moderate hyperkalaemia seems to be the most decisive predictor. Further, MRA discontinuation was associated with increased adjusted risk of all-cause mortality.

Pharmacological Targets in Chronic Heart Failure with Reduced Ejection Fraction

Heart failure management has been repeatedly reviewed over time. This strategy has resulted in improved quality of life, especially in patients with heart failure with reduced ejection fraction (HFrEF). It is for this reason that new mechanisms involved in the development and progression of heart failure, along with specific therapies, have been identified. This review focuses on the most recent guidelines of therapeutic interventions, trials that explore novel therapies, and also new molecules that could improve prognosis of different HFrEF phenotypes.

Prognostic significance of serum potassium in patients hospitalized for acute heart failure

Aim

We investigated the prognostic significance of serum potassium abnormalities at discharge in patients hospitalized for acute heart failure (AHF).

Methods and results

In a retrospective analysis, we included 926 patients hospitalized for AHF, stratified by serum potassium levels at discharge as hypokalaemia (<3.5 mEq/L), normokalaemia (3.5–5.0 mEq/L), and hyperkalaemia (>5.0 mEq/L). The primary endpoint was all‐cause death at 1 year since hospital discharge. At discharge, 40 patients had hypokalaemia (4.3%), 840 normokalaemia (90.7%), and 46 hyperkalaemia (5.0%). Patients with hyperkalaemia at discharge were more frequently men, had more signs of congestion, and lower LVEF while patients with hypokalaemia were more likely to be women with HFpEF. Treatment with ACEi/ARBs and MRAs ≥50% of target dose at discharge was similar across groups. One year all‐cause death occurred in 10% of the patients with hypokalaemia, 13.9% of those with normokalaemia, and 30.4% of those with hyperkalaemia (P = 0.006). After adjustment for covariates, including renal function, background treatment, and baseline potassium level, hyperkalaemia resulted an independent predictor of the primary endpoint (HR 1.96, 95% IC [1.01–3.82]; P = 0.048).

Conclusions

In patients with AHF, the presence of hyperkalaemia at discharge is an independent predictor of 1 year all‐cause death.

Patiromer for the management of hyperkalaemia in patients receiving renin-angiotensin-aldosterone system inhibitors for heart failure: design and rationale of the DIAMOND trial

AIMS

In patients with current or a history of hyperkalaemia, treatment with renin-angiotensin-aldosterone system inhibitors (RAASi) is often compromised. Patiromer, a novel potassium (K⁺ ) binder, may improve serum K⁺ levels and adherence to RAASi.

METHODS

The DIAMOND trial will enroll ∼820 patients with heart failure with reduced ejection fraction (HFrEF; ejection fraction ≤40%). Patients meeting the screening criteria will enter a single-blinded run-in phase where they will be started or continued on a mineralocorticoid receptor antagonist (MRA) titrated to 50 mg/day and other RAASi therapy to ≥50% target dose, and patiromer. Patiromer will be titrated up to a maximum three packs/day (8.4 g/pack) to achieve optimal doses of RAASi without hyperkalaemia. The run-in phase will last up to 12 weeks, following which patients will undergo double-blind randomization in a 1:1 ratio to receive either continued patiromer or placebo (patiromer withdrawal). The primary endpoint is the mean difference in serum K⁺ from randomization between patiromer and placebo arms. Secondary endpoints will include hyperkalaemia events with K⁺ value >5.5 mEq/L, durable enablement of MRA at target dose, investigator-reported adverse events of hyperkalaemia, hyperkalaemia-related clinical endpoints and an overall RAASi use score (using a 0-8-point scale) comprising all-cause death, occurrence of cardiovascular hospitalization or usage of comprehensive heart failure medication.

CONCLUSION

The DIAMOND trial is designed to determine if patiromer can favourably impact K⁺ control in patients with HFrEF with hyperkalaemia or a history of hyperkalaemia leading to RAASi therapy compromise, and in turn improve RAASi use.

Renal function and the effects of vericiguat in patients with worsening heart failure with reduced ejection fraction: insights from the VICTORIA (Vericiguat Global Study in Subjects with HFrEF) trial

AIMS

Vericiguat reduced the primary composite outcome of cardiovascular death or heart failure (HF) hospitalization in patients with worsening HF with reduced ejection fraction (HFrEF) and a lower limit of baseline estimated glomerular filtration rate (eGFR) of 15 mL/min/1.73 m2 . We evaluated the relationship between the efficacy of vericiguat and baseline and subsequent changes in renal function.

METHODS AND RESULTS

In VICTORIA, core laboratory serum creatinine was measured at baseline (n = 4956) and weeks 16, 32, and 48. Worsening renal function (WRF), defined as an increase ≥0.3 mg/dL in creatinine from baseline to week 16, was assessed via a Cox model with respect to subsequent primary events. Mean age was 69 years, 24% were female, and mean baseline eGFR was 61 mL/min/1.73 m2 . During 48 weeks of treatment, the trajectories in eGFR and creatinine with vericiguat were similar to placebo (P = 0.50 and 0.18). The beneficial effects of vericiguat on the primary outcome were not influenced by baseline eGFR (interaction P = 0.48). WRF occurred in 15% of patients and was associated with worse outcomes (adjusted hazard ratio 1.28, 95% confidence interval 1.11-1.47; P < 0.001), but the beneficial effects of vericiguat on the primary outcome were similar in patients with or without WRF (interaction P = 0.76).

CONCLUSION

Renal function trajectories were similar between vericiguat- and placebo-treated patients and the beneficial effects of vericiguat on the primary outcome were consistent across the full range of eGFR and irrespective of WRF.

Hyperkalemia in Chronic Kidney Disease in the New Era of Kidney Protection Therapies

Despite recent therapeutic advances, chronic kidney disease (CKD) is one of the fastest growing global causes of death. This illustrates limitations of current therapeutic approaches and, potentially, unidentified knowledge gaps. For decades, renin-angiotensin-aldosterone system (RAAS) blockers have been the mainstay of therapy for CKD. However, they favor the development of hyperkalemia, which is already common in CKD patients due to the CKD-associated decrease in urinary potassium (K⁺) excretion and metabolic acidosis. Hyperkalemia may itself be life-threatening as it may trigger potentially lethal arrhythmia, and additionally may limit the prescription of RAAS blockers and lead to low-K⁺ diets associated to low dietary fiber intake. Indeed, hyperkalemia is associated with adverse kidney, cardiovascular, and survival outcomes. Recently, novel kidney protective therapies, ranging from sodium/glucose cotransporter 2 (SGLT2) inhibitors to new mineralocorticoid receptor antagonists have shown efficacy in clinical trials. Herein, we review K⁺ pathophysiology and the clinical impact and management of hyperkalemia considering these developments and the availability of the novel K⁺ binders patiromer and sodium zirconium cyclosilicate, recent results from clinical trials targeting metabolic acidosis (sodium bicarbonate, veverimer), and an increasing understanding of the role of the gut microbiota in health and disease.

Clinical Management of Hyperkalemia

Hyperkalemia is an electrolyte abnormality with potentially life-threatening consequences. Despite various guidelines, no universally accepted consensus exists on best practices for hyperkalemia monitoring, with variations in precise potassium (K⁺) concentration thresholds or for the management of acute or chronic hyperkalemia. Based on the available evidence, this review identifies several critical issues and unmet needs with regard to the management of hyperkalemia. Real-world studies are needed for a better understanding of the prevalence of hyperkalemia outside the clinical trial setting. There is a need to improve effective management of hyperkalemia, including classification and K⁺ monitoring, when to reinitiate previously discontinued renin-angiotensin-aldosterone system inhibitor (RAASi) therapy, and when to use oral K⁺-binding agents. Monitoring serum K⁺ should be individualized; however, increased frequency of monitoring should be considered for patients with chronic kidney disease, diabetes, heart failure, or a history of hyperkalemia and for those receiving RAASi therapy. Recent clinical studies suggest that the newer K⁺ binders (patiromer sorbitex calcium and sodium zirconium cyclosilicate) may facilitate optimization of RAASi therapy. Enhancing the knowledge of primary care physicians and internists with respect to the safety profiles of these newer K⁺ binders may increase confidence in managing patients with hyperkalemia. Lastly, the availability of newer K⁺-binding agents requires further study to establish whether stringent dietary K⁺ restrictions are needed in patients receiving K⁺-binder therapy. Individualized monitoring of serum K⁺ among patients with an increased risk of hyperkalemia and the use of newer K⁺-binding agents may allow for optimization of RAASi therapy and more effective management of hyperkalemia.

Management of RAASi-associated hyperkalemia in patients with cardiovascular disease

Renin-angiotensin-aldosterone system inhibitors (RAASi) reduce morbidity and mortality in heart failure (HF) with reduced ejection fraction in a dose-dependent manner. They also have a positive impact in other cardiovascular diseases (CVDs). However, RAASi may induce hyperkalemia, a potentially life-threatening disorder. This risk is further increased in those with concomitant chronic kidney disease, diabetes mellitus, and/or in patients with hypertension. Current treatment guidelines recommend maximal RAASi dosing to improve clinical outcomes; however, this is often limited by the development of hyperkalemia. When this occurs, current guidelines recommend RAASi down-titration/interruption, which, while improving short-term prognosis, is associated with a negative long-term prognostic impact. At present, the European Society of Cardiology suggests the consideration of novel potassium binders (patiromer and sodium zirconium cyclosilicate) for the management of RAASi-associated hyperkalemia. Both drugs can reduce serum potassium levels and prevent recurrent hyperkalemia. Additionally, patiromer showed enabling of RAASi optimization in high-risk patients. Nevertheless, precise recommendations on the use of these drugs are lacking. Building upon current HF guideline recommendations, a multidisciplinary expert panel convened to design an algorithm providing practical guidance on the use of novel potassium binders/patiromer in patients with HF and/or other CVD. As a result of that effort, we present an evidence-based treatment algorithm for the management of hyperkalemia with novel potassium binders/patiromer in patients with HF and/or other CVD receiving RAASi, including the necessary monitoring to avoid induction of hypokalemia. This algorithm aims to maintain or up-titrate RAASi to optimized doses, while maintaining normokalemia, improved clinical outcomes, and long-term prognosis.

Abnormalities of Potassium in Heart Failure: JACC State-of-the-Art Review

Potassium (K⁺) is the most abundant cation in humans and is essential for normal cellular function. Alterations in K⁺ regulation can lead to neuromuscular, gastrointestinal, and cardiac abnormalities. Dyskalemia (i.e., hypokalemia and hyperkalemia) in heart failure is common because of heart failure itself, related comorbidities, and medications. Dyskalemia has important prognostic implications. Hypokalemia is associated with excess morbidity and mortality in heart failure. The lower the K⁺ levels, the higher the risk, starting at K⁺ levels below approximately 4.0 mmol/l, with a steep risk increment with K⁺ levels <3.5 mmol/l. Hyperkalemia (>5.5 mmol/l) has also been associated with increased risk of adverse events; however, this association is prone to reverse-causation bias as stopping renin angiotensin aldosterone system inhibitor therapy in the advent of hyperkalemia likely contributes the observed risk. In this state-of-the-art review, practical and easy-to-implement strategies to deal with both hypokalemia and hyperkalemia are provided as well as guidance for the use of potassium-binders.

Heart failure in the last year: progress and perspective

Research about heart failure (HF) has made major progress in the last years. We give here an update on the most recent findings. Landmark trials have established new treatments for HF with reduced ejection fraction. Sacubitril/valsartan was superior to enalapril in PARADIGM-HF trial, and its initiation during hospitalization for acute HF or early after discharge can now be considered. More recently, new therapeutic pathways have been developed. In the DAPA-HF and EMPEROR-Reduced trials, dapagliflozin and empagliflozin reduced the risk of the primary composite endpoint, compared with placebo [hazard ratio (HR) 0.74; 95% confidence interval (CI) 0.65-0.85; P < 0.001 and HR 0.75; 95% CI 0.65-0.86; P < 0.001, respectively]. Second, vericiguat, an oral soluble guanylate cyclase stimulator, reduced the composite endpoint of cardiovascular death or HF hospitalization vs. placebo (HR 0.90; 95% CI 0.82-0.98; P = 0.02). On the other hand, both the diagnosis and treatment of HF with preserved ejection fraction, as well as management of advanced HF and acute HF, remain challenging. A better phenotyping of patients with HF would be helpful for prognostic stratification and treatment selection. Further aspects, such as the use of devices, treatment of arrhythmias, and percutaneous treatment of valvular heart disease in patients with HF, are also discussed and reviewed in this article.

Normal range of serum potassium, prevalence of dyskalaemia and associated factors in Chinese older adults: a cross-sectional study

OBJECTIVE

To investigate the normal range of serum potassium, the prevalence of dyskalaemia and the associated factors in Chinese older adults.

DESIGN

A cross-sectional study conducted from September 2017 to March 2018.

SETTING

Forty-eight community elderly care facilities in four regions in northern China.

PARTICIPANTS

A total of 1266 (308 apparently healthy and 958 unhealthy) participants 55 years or older and with fasting serum potassium measured.

MAIN OUTCOME MEASURES AND METHODS

Serum potassium <3.5 mEq/L and >5.5 mEq/L (guidelines definition) and <2.5th and >97.5th percentiles of the distribution among healthy participants (our study definition) were both used to define hypokalaemia and hyperkalaemia, respectively. Multivariable generalised estimating equation models were used to adjust for clustering effect in the analyses of factors associated with risk of dyskalaemia and with variations in serum potassium.

RESULTS

The study participants had a mean age of 70 (8.8) years. Among apparently healthy participants, the 2.5th and 97.5th percentiles of serum potassium distribution were 3.7 mEq/L and 5.3 mEq/L, respectively. Using the study definition, the prevalence of hyperkalaemia was 4.3% (95% CI 3.2% to 5.4%) and of hypokalaemia was 4.0% (95% CI 2.9% to 5.1%). Multivariable analyses showed that risk of hyperkalaemia was associated with unhealthy conditions (OR=2.21; 95% CI 1.17 to 4.18); risk of hypokalaemia was associated with unhealthy conditions (OR=2.56; 95% CI 1.05 to 6.23), older age (OR=1.70 per 10-year increase; 95% CI 1.04 to 2.79) and region (OR=16.87; 95% CI 6.41 to 44.38); and higher serum potassium was associated with male gender (mean difference (MD)=0.12; 95% CI 0.05 to 0.19) and estimated glomerular filtration rate <60 mL/min/1.73 m² (MD=0.29; 95% CI 0.12 to 0.46). Using the guidelines definition, hyperkalaemia accounted for 2.7% (1.8%, 3.6%) and hypokalaemia 1.8% (1.1%, 2.5%). Analyses of the associated factors showed similar trends.

CONCLUSIONS

The study suggested a narrower normal range of serum potassium for defining dyskalaemia, which was common in older Chinese and more prevalent in unhealthy ones.

TRIAL REGISTRATION NUMBER

NCT03290716; Pre-results.

Effects of hyperkalaemia and non-adherence to renin-angiotensin-aldosterone system inhibitor therapy in patients with heart failure in Italy: a propensity-matched study

Aims

The aims of this study were to evaluate if the risk of cardiovascular events and all‐cause mortality was higher in the presence of hyperkalaemia (HK) in patients with heart failure (HF) treated with renin–angiotensin–aldosterone system inhibitors (RAASi), and to investigate in this cohort the increased risk of cardiovascular events and all‐cause mortality among HK patients with non‐optimal adherence to RAASi therapy.

Methods and results

In this retrospective cohort study based on administrative databases of five Italian Local Health Units, all adult patients with a HF diagnosis between January 2010 and December 2017 were included only if they were prescribed RAASi therapy during the first 3 months after the index date, that corresponded to the date of first HF diagnosis during the inclusion period. Patients were considered to have HK if serum potassium level was ≥5.5 mmol/L. A propensity score matching was applied before evaluation of hazard ratios. Patients with HK were 37% (P < 0.001) and 70% (P < 0.001), respectively, more at risk of cardiovascular events and of dying for all‐cause mortality compared to non‐HK patients. Among the HK group, patients non‐adherent to RAASi therapy had a 39% (P = 0.105) higher risk of cardiovascular events and a twofold increased risk (P < 0.001) of all‐cause death.

Conclusion

Findings from this real‐world study showed that in a cohort of HF patients under RAASi therapy, subjects with HK had an enhanced risk of cardiovascular events or death compared to patients without HK. Moreover, in HK patients, sub‐optimal adherence to RAASi therapy was associated with an increased risk of all‐cause mortality.

Dyskalemia: a management problem for students

BACKGROUND

Although dyskalemia is common, its management can be problematic for students and general practitioners, especially when it occurs in patients with heart and renal failure. The basic academic knowledge of general medicine students, who have often not yet encountered clinical situations of dyskalemia, remains unclear in this regard.

OBJECTIVES

The purpose of this study was to evaluate the knowledge and reflexive practices of general medicine students in regard to dyskalemia.

METHODS

A cross-sectional survey, based on a self-questionnaire, of all of the students enrolled in general medicine studies at the Faculty of Medicine at the University of Nancy (France) at the end of their degree. The students were asked questions pertaining to specific clinical situations. The answers were compared to the information provided in the medical curriculum as well as to the relevant European guidelines.

RESULTS

We collected 290 of the questionnaires (participation rate: 81.2%). The hyper- and hypokalemia thresholds considered pathological (3.5-5.0 mmol/L) were known by 78% and 67% of the students, respectively. The perception of danger in case of severe hypokalemia was underestimated by 62.7% of them. In most cases, the proposed management of hyperkalemia in heart and renal failure did not comply with the relevant guidelines. The students tended to favor permanent discontinuation of the administration of converting enzyme inhibitors (ACE) and/or mineralocorticoid receptor antagonists (MRA) without considering the need for their reintroduction (51.6%). Sodium polystyrene sulfate was frequently seen as an appropriate first-line treatment for hyperkalemia (45%).

CONCLUSIONS

The knowledge and competence of general medicine students appear to be lacking for hyperkalemia in heart and renal failure, and they are long way from full compliance with the relevant European guidelines. Exposure to complex clinical situations as part of the medical curriculum, therefore, seems essential to improve the way dyskalemia is managed in France.

Serum potassium and heart failure: association, causation, and clinical implications

Dyskalemia (hypo- and hyperkalemia) is a common clinical encounter in patients with heart failure (HF), linked to underlying pathophysiologic alterations, pharmacological treatments, and concomitant comorbidities. Both hypo- and hyperkalemia have been associated with a poor outcome in HF. However, it is not known if this association is causal. In order to investigate this relation, we implemented the Bradford Hill criteria for causation examining the available literature. Of note, hypokalemia and low-normal potassium levels (serum potassium < 4.0 mmol/L) appear to be associated with adverse clinical outcomes in HF in a cause-and-effect manner. Conversely, a cause-and-effect relationship between hyperkalemia (serum potassium > 5.0 mmol/L) and adverse clinical outcomes in HF appears unlikely. We also examined the benefits of renin-angiotensin-aldosterone system inhibitors (RAASi) therapy uptitration in patients with HF and reduced ejection fraction. In fact, hyperkalemia often limits RAASi use, thereby negating or mitigating their clinical benefits. Finally, serum potassium levels in HF should be maintained within the range of 4.0-5.0 mmol/L, and although the correction of hyperkalemia does not appear to improve clinical outcomes per se, it may enable the optimal titration of RAASi, offering indirect clinical benefit.

Real-World Epidemiology of Potassium Derangements Among Chronic Cardiovascular, Metabolic and Renal Conditions: A Population-Based Analysis

BACKGROUND

The aims of the present analysis are to estimate the prevalence of five key chronic cardiovascular, metabolic and renal conditions at the population level, the prevalence of renin-angiotensin-aldosterone system inhibitor (RAASI) medication use and the magnitude of potassium (K+) derangements among RAASI users.

METHODS AND RESULTS

We used data from more than 375,000 individuals, 55 years of age or older, included in the population-based healthcare database of the Catalan Institute of Health between 2015 and 2017. The conditions of interest were chronic heart failure (CHF), chronic kidney disease (CKD), diabetes mellitus, ischemic heart disease and hypertension. RAASI medications included angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, mineralocorticoid receptor antagonists (MRAs) and renin inhibitors. Hyperkalemia was defined as K+ levels >5.0 mEq/L and hypokalemia as K+ <3.5 mEq/L. The prevalence of chronic cardiovascular, metabolic and renal conditions was high, and particularly that of hypertension (prevalence ranging from 48.2% to 48.9%). The use of at least one RAASI medication was almost ubiquitous in these patients (75.2-77.3%). Among RAASI users, the frequency of K+ derangements, mainly of hyperkalemia, was very noticeable (12% overall), particularly in patients with CKD or CHF, elderly individuals and users of MRAs. Hypokalemia was less frequent (1%).

CONCLUSION

The high prevalence of K+ derangements, and particularly hyperkalemia, among RAASI users highlights the real-world relevance of K+ derangements, and the importance of close monitoring and management of K+ levels in routine clinical practice. This is likely to benefit a large number of patients, particularly those at higher risk.

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.

Unravelling the interplay between hyperkalaemia, renin-angiotensin-aldosterone inhibitor use and clinical outcomes. Data from 9222 chronic heart failure patients of the ESC-HFA-EORP Heart Failure Long-Term Registry

AIMS

We assessed the interplay between hyperkalaemia (HK) and renin-angiotensin-aldosterone system inhibitor (RAASi) use, dose and discontinuation, and their association with all-cause or cardiovascular death in patients with chronic heart failure (HF). We hypothesized that HK-associated increased death may be related to RAASi withdrawal.

METHODS AND RESULTS

The ESC-HFA-EORP Heart Failure Long-Term Registry was used. Among 9222 outpatients (HF with reduced ejection fraction: 60.6%, HF with mid-range ejection fraction: 22.9%, HF with preserved ejection fraction: 16.5%) from 31 countries, 16.6% had HK (≥5.0 mmol/L) at baseline. Angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) was used in 88.3%, a mineralocorticoid receptor antagonist (MRA) in 58.7%, or a combination in 53.2%; of these, at ≥50% of target dose in ACEi: 61.8%; ARB: 64.7%; and MRA: 90.3%. At a median follow-up of 12.2 months, there were 789 deaths (8.6%). Both hypokalaemia and HK were independently associated with higher mortality, and ACEi/ARB prescription at baseline with lower mortality. MRA prescription was not retained in the model. In multivariable analyses, HK at baseline was independently associated with MRA non-prescription at baseline and subsequent discontinuation. When considering subsequent discontinuation of RAASi (instead of baseline use), HK was no longer found associated with all-cause deaths. Importantly, all RAASi (ACEi, ARB, or MRA) discontinuations were strongly associated with mortality.

CONCLUSIONS

In HF, hyper- and hypokalaemia were associated with mortality. However, when adjusting for RAASi discontinuation, HK was no longer associated with mortality, suggesting that HK may be a risk marker for RAASi discontinuation rather than a risk factor for worse outcomes.

Hyperkalemia in heart failure: Foe or friend?

Hyperkalemia is a frequent and sometimes life‐threatening condition that may be associated with arrhythmia and cardiac dysfunction in patients with heart failure (HF). High potassium levels in HF represent both a direct risk for cardiovascular complication and an indirect biomarker of the severity of the underlying disease, reflecting neurohormonal activation and renal dysfunction. Evaluating the prevalence and significance of hyperkalemia in HF patients is essential for optimizing the use of potassium sparing agents, such the renin–angiotensin–aldosterone system inhibitors (RAASi) or angiotensin receptor‐neprilysin inhibitors and mineralocorticoid receptor antagonists, which represent a well‐established cornerstone and life‐saving therapy. In this review we discuss recent findings and current concepts related to the epidemiology, pathological mechanisms and implications of hyperkalemia, as well as novel therapeutic approaches to counteract it in patients with HF. The balance between optimizing life‐saving potassium sparing medication and minimizing hyperkalemia‐associated risk is much needed in patients with HF. Although older potassium‐binding agents are associated with serious adverse events, novel potassium‐binding drugs are effective in lowering potassium levels and are generally well tolerated. Novel potassium‐binding drugs, such as patiromer and sodium zirconium cyclosilicate, may help to optimize therapy in HF and achieve guideline‐recommended doses. Hyperkalemia is common in HF patients and is associated with a poorer prognosis and an increased risk of cardiovascular complications: Contrariwise, “moderate” potassium levels go with a better prognosis, while the emergence of new drugs, potassium binders, could allow target doses of RAASi to be achieved.

Optimally managing hyperkalemia in patients with cardiorenal syndrome

Renin-angiotensin-aldosterone system inhibitors (RAASi) are now a standard treatment in most patients with cardiovascular disease, especially in those with heart failure (HF). The European Society of Cardiology and the American College of Cardiology/American Heart Association gave a Class IA recommendation for the use of RAASi in the treatment of Classes II-IV symptomatic HF with reduced ejection fraction (HFREF), based on their strong clinical benefits of lowering all-cause mortality and HF hospitalizations in these subjects. However, RAASi therapy or adding mineralocorticoid receptor antagonists in subjects receiving background angiotensin-converting enzyme inhibitors or angiotensin receptor blockers may be associated with an increased risk of hyperkalemia (HK), especially in those with reduced kidney function. As a result, a significant proportion of these subjects either have RAASi dose reduced or more often discontinued when they develop HK. Discontinuation of RAASi in patients hospitalized with HFREF was associated with higher postdischarge mortality and rehospitalization rates, while optimal dosing of RAASi significantly reduced median hospital stays, outpatient visits and related costs. Thus, effective treatment is required to lower potassium level and maintain normokalemia in subjects with HF and reduced kidney disease who develop or are at risk of HK, thus enabling them to continue their RAASi therapy and maximize benefits from RAASi. In this review, we provide an up-to-date review of the prevalence and significance of HK in patients with cardiorenal syndrome, as well as their optimal management of HK with recent novel therapies.

Tailoring treatment of hyperkalemia

Hyperkalemia is a common electrolyte disorder that may be rapidly life-threatening because of its cardiac toxicity. Hyperkalemia risk factors are numerous and often combined in the same patient. Most of the strategies to control serum potassium level in the short term have been used for decades. However, evidence for their efficacy and safety remains low. Treatment of hyperkalemia remains challenging, poorly codified, with a risk of overtreatment, including short-term side effects, and with the priority of avoiding unnecessary hospital stays or chronic medication changes. Recently, new oral treatments have been proposed for non-life-threatening hyperkalemia, with encouraging results. Their role in the therapeutic arsenal remains uncertain. Finally, a growing body of evidence suggests that hyperkalemia might negatively impact outcomes in the long term in patients with chronic heart failure or kidney failure through underdosing or withholding of cardiovascular medication (e.g. renin-angiotensin-aldosterone system inhibitors). Recognition of efficacy and potential side effects of treatment may help in tailoring treatments to the patient's status and conditions. In this review we discuss how treatment of hyperkalemia could be tailored to the patient's conditions and status, both on the short and mid term.

Medication as a risk factor for hospitalization due to heart failure and shock: a series of case-crossover studies in Swiss claims data

Purpose

Heart failure is among the leading causes for hospitalization in Europe. In this study, we evaluate potential precipitating factors for hospitalization for heart failure and shock.

Methods

Using Swiss claims data (2014–2015), we evaluated the association between hospitalization for heart failure and shock, and prescription of oral potassium supplements, non-steroidal anti-inflammatory drugs (NSAIDs), and amoxicillin/clavulanic acid. We conducted case-crossover analyses, where exposure was compared for the hazard period and the primary control period (e.g., 1–30 days before hospitalization vs. 31–60 days, respectively). Conditional logistic regression was applied and subsequently adjusted for addressing potential confounding by disease progression. Sensitivity analyses were conducted and stratification for co-medication was performed.

Results

We identified 2185 patients hospitalized with heart failure or shock. Prescription of potassium supplements, NSAIDs, and amoxicillin/clavulanic acid was significantly associated with an increased risk for hospitalization for heart failure and shock with crude odds ratios (OR) of 2.04 for potassium (95% CI 1.24–3.36, p = 0.005, 30 days), OR 1.8 for NSAIDs (95% CI 1.39–2.33, p < 0.0001, 30 days), and OR 3.25 for amoxicillin/clavulanic acid (95% CI 2.06–5.14, p < 0.0001, 15 days), respectively. Adjustment attenuated odds ratios, while the significant positive association remained (potassium OR 1.70 (95% CI 1.01–2.86, p = 0.046), NSAIDs OR 1.50 (95% CI 1.14–1.97, p = 0.003), and amoxicillin/clavulanic acid OR 2.26 (95% CI 1.41–3.62, p = 0.001).

Conclusion

Prescription of potassium supplements, NSAIDs, and amoxicillin/clavulanic acid is associated with increased risk for hospitalization. Underlying conditions such as pain, electrolyte imbalances, and infections are likely contributing risk factors. Physicians may use this knowledge to better identify patients at risk and adapt patient management.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02835-x) contains supplementary material, which is available to authorized users.

Mineralcorticoid Receptor Antagonist Withdrawal for Hyperkalemia and Mortality in Patients with Heart Failure

Background: Hyperkalemia is one of the most frequent side effects related to renin-angiotensin-aldosterone system (RAAS) inhibition, and can influence optimization of heart failure (HF) therapy. Aim: To evaluate the occurrence of hyperkalemia in a series of outpatients with chronic HF and its relationship with RAAS inhibitor therapy. Method: We evaluated consecutive outpatients with HF and a reduced left ventricular ejection fraction. The incidence of hyperkalemia and consequent changes in RAAS inhibitor therapy were evaluated for each patient. Results: A history of hyperkalemia or at least 1 episode of hyperkalemia during follow-up was observed in 104 of 351 patients. Hyperkalemia mainly influenced mineralocorticoid receptor antagonist (MRA) therapy and, among patients with hyperkalemia, not taking MRA was associated with a greater risk of death on univariate analysis (HR = 6.39; 95% CI 2.76–14.79, p < 0.001) and multivariate analysis (HR = 5.24; 95% CI 1.87–14.72, p = 0.002) after correction for age, ischemic cardiomyopathy, diabetes, systolic arterial pressure, New York Heart Association class 3, left ventricular ejection fraction, presence of hyponatremia, glomerular filtration rate calculated by the EPI formula, and presence of N-terminal pro-B-type natriuretic peptide >1,000 pg/mL. Conclusion: The occurrence of hyperkalemia is common among outpatients with HF and it is the main cause of MRA withdrawal, which is associated with a worse prognosis. In this setting, the possibility of managing hyperkalemia using new classes of drugs could allow continuation of MRA therapy.

New perspectives and future directions in the treatment of heart failure

The management of heart failure has changed significantly over the last 30 years, leading to improvements in the quality of life and outcomes, at least for patients with a substantially reduced left ventricular ejection fraction (HFrEF). This has been made possible by the identification of various pathways leading to the development and progression of heart failure, which have been successfully targeted with effective therapies. Meanwhile, many other potential targets of treatment have been identified, and the list is constantly expanding. In this review, we summarise planned and ongoing trials exploring the potential benefit, or harm, of old and new pharmacological interventions that might offer further improvements in treatment for those with HFrEF and extend success to the treatment of patients with heart failure with preserved left ventricular ejection fraction (HFpEF) and other heart failure phenotypes.

Plasma proteomic approach in patients with heart failure: insights into pathogenesis of disease progression and potential novel treatment targets

AIMS

To provide insights into pathogenesis of disease progression and potential novel treatment targets for patients with heart failure by investigation of the plasma proteome using network analysis.

METHODS AND RESULTS

The plasma proteome of 50 patients with heart failure who died or were rehospitalised were compared with 50 patients with heart failure, matched for age and sex, who did not have an event. Peptides were analysed on two-dimensional liquid chromatography coupled to tandem mass spectrometry (2D LC ESI-MS/MS) in high definition mode (HDMSE). We identified and quantified 3001 proteins, of which 51 were significantly up-regulated and 46 down-regulated with more than two-fold expression changes in those who experienced death or rehospitalisation. Gene ontology enrichment analysis and protein-protein interaction networks of significant differentially expressed proteins discovered the central role of metabolic processes in clinical outcomes of patients with heart failure. The findings revealed that a cluster of proteins related to glutathione metabolism, arginine and proline metabolism, and pyruvate metabolism in the pathogenesis of poor outcome in patients with heart failure who died or were rehospitalised.

CONCLUSIONS

Our findings show that in patients with heart failure who died or were rehospitalised, the glutathione, arginine and proline, and pyruvate pathways were activated. These pathways might be potential targets for therapies to improve poor outcomes in patients with heart failure.

Sex- and age-related differences in the management and outcomes of chronic heart failure: an analysis of patients from the ESC HFA EORP Heart Failure Long-Term Registry

AIMS

This study aimed to assess age- and sex-related differences in management and 1-year risk for all-cause mortality and hospitalization in chronic heart failure (HF) patients.

METHODS AND RESULTS

Of 16 354 patients included in the European Society of Cardiology Heart Failure Long-Term Registry, 9428 chronic HF patients were analysed [median age: 66 years; 28.5% women; mean left ventricular ejection fraction (LVEF) 37%]. Rates of use of guideline-directed medical therapy (GDMT) were high (angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, beta-blockers and mineralocorticoid receptor antagonists: 85.7%, 88.7% and 58.8%, respectively). Crude GDMT utilization rates were lower in women than in men (all differences: P ≤ 0.001), and GDMT use became lower with ageing in both sexes, at baseline and at 1-year follow-up. Sex was not an independent predictor of GDMT prescription; however, age >75 years was a significant predictor of GDMT underutilization. Rates of all-cause mortality were lower in women than in men (7.1% vs. 8.7%; P = 0.015), as were rates of all-cause hospitalization (21.9% vs. 27.3%; P < 0.001) and there were no differences in causes of death. All-cause mortality and all-cause hospitalization increased with greater age in both sexes. Sex was not an independent predictor of 1-year all-cause mortality (restricted to patients with LVEF ≤45%). Mortality risk was significantly lower in patients of younger age, compared to patients aged >75 years.

CONCLUSIONS

There was a decline in GDMT use with advanced age in both sexes. Sex was not an independent predictor of GDMT or adverse outcomes. However, age >75 years independently predicted lower GDMT use and higher all-cause mortality in patients with LVEF ≤45%.

The role of cathepsin D in the pathophysiology of heart failure and its potentially beneficial properties: a translational approach

Aims

Cathepsin D is a ubiquitous lysosomal protease that is primarily secreted due to oxidative stress. The role of circulating cathepsin D in heart failure (HF) is unknown. The aim of this study is to determine the association between circulating cathepsin D levels and clinical outcomes in patients with HF and to investigate the biological settings that induce the release of cathepsin D in HF.

Methods and results

Cathepsin D levels were studied in 2174 patients with HF from the BIOSTAT‐CHF index study. Results were validated in 1700 HF patients from the BIOSTAT‐CHF validation cohort. The primary combined outcome was all‐cause mortality and/or HF hospitalizations. Human pluripotent stem cell‐derived cardiomyocytes were subjected to hypoxic, pro‐inflammatory signalling and stretch conditions. Additionally, cathepsin D expression was inhibited by targeted short hairpin RNAs (shRNA). Higher levels of cathepsin D were independently associated with diabetes mellitus, renal failure and higher levels of interleukin‐6 and N‐terminal pro‐B‐type natriuretic peptide (P < 0.001 for all). Cathepsin D levels were independently associated with the primary combined outcome [hazard ratio (HR) per standard deviation (SD): 1.12; 95% confidence interval (CI) 1.02–1.23], which was validated in an independent cohort (HR per SD: 1.23, 95% CI 1.09–1.40). In vitro experiments demonstrated that human stem cell‐derived cardiomyocytes released cathepsin D and troponin T in response to mechanical stretch. ShRNA‐mediated silencing of cathepsin D resulted in increased necrosis, abrogated autophagy, increased stress‐induced metabolism, and increased release of troponin T from human stem cell‐derived cardiomyocytes under stress.

Conclusions

Circulating cathepsin D levels are associated with HF severity and poorer outcome, and reduced levels of cathepsin D may have detrimental effects with therapeutic potential in HF.

Highlights in heart failure

Heart failure (HF) remains a major cause of mortality, morbidity, and poor quality of life. It is an area of active research. This article is aimed to give an update on recent advances in all aspects of this syndrome. Major changes occurred in drug treatment of HF with reduced ejection fraction (HFrEF). Sacubitril/valsartan is indicated as a substitute to ACEi/ARBs after PARADIGM-HF (hazard ratio [HR], 0.80; 95% confidence interval [CI], 0.73 to 0.87 for sacubitril/valsartan vs. enalapril for the primary endpoint and Wei, Lin and Weissfeld HR 0.79, 95% CI 0.71-0.89 for recurrent events). Its initiation was then shown as safe and potentially useful in recent studies in patients hospitalized for acute HF. More recently, dapagliflozin and prevention of adverse-outcomes in DAPA-HF trial showed the beneficial effects of the sodium-glucose transporter type 2 inhibitor dapaglifozin vs. placebo, added to optimal standard therapy [HR, 0.74; 95% CI, 0.65 to 0.85;0.74; 95% CI, 0.65 to 0.85 for the primary endpoint]. Trials with other SGLT 2 inhibitors and in other patients, such as those with HF with preserved ejection fraction (HFpEF) or with recent decompensation, are ongoing. Multiple studies showed the unfavourable prognostic significance of abnormalities in serum potassium levels. Potassium lowering agents may allow initiation and titration of mineralocorticoid antagonists in a larger proportion of patients. Meta-analyses suggest better outcomes with ferric carboxymaltose in patients with iron deficiency. Drugs effective in HFrEF may be useful also in HF with mid-range ejection fraction. Better diagnosis and phenotype characterization seem warranted in HF with preserved ejection fraction. These and other burning aspects of HF research are summarized and reviewed in this article.

Hyperkalaemia: aetiology, epidemiology, and clinical significance

Disturbances in the potassium homeostasis are common among patients with heart failure (HF) and negatively affect clinical outcome. Patients with HF have a higher prevalence of common risk factors related to hyperkalaemia, including diabetes mellitus, hypertension, and chronic kidney disease. Furthermore, the use of renin-angiotensin-aldosterone system (RAAS) inhibitors, is an important risk factor for developing hyperkalaemia. The association between hyperkalaemia and mortality is not unequivocal, depends on the study type (trial vs. real-world setting) and is often confounded. More importantly, hyperkalaemia is an important cause of discontinuation or failure to uptitrate to guideline recommended dosages of RAAS inhibitors, which in turn may negatively impact clinical outcomes. The goal of this review is to discuss the epidemiology, aetiology, and clinical consequences of potassium disturbances in HF.

Potassium homoeostasis and pathophysiology of hyperkalaemia

Determination of potassium level is one of the most frequent laboratory tests in clinical medicine. Hyperkalaemia is defined as a potassium level >5.0 mmol/L and is one of the most clinically important electrolyte abnormalities, because it may cause dangerous cardiac arrhythmia and sudden cardiac death. Here, we review methodological challenges in the determination of potassium levels, important clinical aspects of the potassium homoeostasis as well as of the pathophysiology of hyperkalaemia.

Serum potassium and clinical outcomes in heart failure patients: results of risk calculations in 21 334 patients in the UK

Aims

At present, the clinical burden of hypokalaemia and hyperkalaemia among European heart failure patients, and relationships between serum potassium and adverse clinical outcomes in this population, is not well characterized. The aim of this study was to investigate associations between mortality, major adverse cardiac events, and renin–angiotensin–aldosterone system inhibitor (RAASi) discontinuation across serum potassium levels, in a UK cohort of incident heart failure patients.

Methods and results

This was a retrospective observational cohort study of newly diagnosed heart failure patients listed in the Clinical Practice Research Datalink, with a first record of heart failure (index date) between 2006 and 2015. Hypokalaemia and hyperkalaemia episodes were defined as the number of serum potassium measurements exceeding each threshold (<3.5, ≥5.0, ≥5.5, and ≥6.0 mmol/L), without such a measurement in the preceding 7 days. Risk equations developed using Poisson generalized estimating equations were utilized to estimate adjusted incident rate ratios (IRRs) relating serum potassium and clinical outcomes (death, major adverse cardiac event, and RAASi discontinuation). Among 21,334 eligible heart failure patients, 1969 (9.2%), 7648 (35.9%), 2725 (12.8%), and 763 (3.6%) experienced episodes of serum potassium <3.5, ≥5.0, ≥5.5, and ≥6.0 mmol/L, respectively. The adjusted IRRs for mortality exhibited a U‐shaped association pattern with serum potassium. Relative to the reference category (4.5 to <5.0 mmol/L), adjusted IRRs for mortality were estimated as 1.98 (95% confidence interval: 1.69–2.33), 1.23 (1.12–1.36), 1.35 (1.14–1.60), and 3.02 (2.28–4.02), for patients with serum potassium <3.5, ≥5.0 to <5.5, ≥5.5 to <6.0, and ≥6.0 mmol/L, respectively. The adjusted IRRs for major adverse cardiac events demonstrated a non‐statistically significant relationship with serum potassium. Discontinuation of RAASi therapy exhibited a J‐shaped trend in association with serum potassium. Compared with the reference category (4.5 to <5.0 mmol/L), adjusted IRRs were estimated as 1.07 (0.89–1.28) in patients with serum potassium <3.5 mmol/L, increasing to 1.32 (1.14–1.53) and 2.19 (1.63–2.95) among those with serum potassium ≥5.5 to <6.0 and ≥6.0 mmol/L, respectively.

Conclusions

In UK patients with new onset heart failure, both hypokalaemia and hyperkalaemia were associated with increased mortality risk, and hyperkalaemia was associated with increased likelihood of RAASi discontinuation. Our results demonstrate the potential importance of serum potassium monitoring for heart failure outcomes and management.