Hyponatremia and Heart Failure?Treatment Considerations

Hyponatremia in Stable Patients with Advanced Heart Failure: Association to Hemodynamics and Outcome

INTRODUCTION

Hyponatremia is associated with worse outcomes in patients with chronic heart failure (HF) and reduced ejection fraction (HFrEF). However, it is unclear whether the worse prognosis is driven by hemodynamic derangement and how this potentially could be associated with hyponatremia.

METHODS

The study included 502 patients with HFrEF evaluated for advanced HF therapies, who underwent a right heart catheterization (RHC). Hyponatremia was defined as p-Na ≤136 mmol/L. The risk of all-cause mortality and a composite endpoint including mortality, left ventricular assist device (LVAD) implantation, implantation of total artificial heart (TAH), or heart transplantation (HTx) was evaluated using Cox regression analyses and Kaplan-Meier models.

RESULTS

Included patients were predominantly men 79% and had a median age of 54 years (IQR: 43-62). A third (165) of the patients had hyponatremia. In both univariate and multivariate regression analyses, p-Na was associated with increased central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP), and mean pulmonary artery pressure (mPAP) but not with cardiac index. Hyponatremia was significantly associated with the combined endpoint (HR: 1.36 [95% CI, 1.07-1.74]; p = 0.01), but not all-cause mortality in adjusted Cox models.

CONCLUSION

In stable HFrEF patients evaluated for advanced HF therapies, lower p-Na was associated with more deranged invasive hemodynamic measurements. Hyponatremia remained significantly associated with the combined endpoint but not all-cause mortality in adjusted Cox models. The study suggests that the increased mortality associated with hyponatremia in HFrEF patients could partly be driven by hemodynamic derangement.

Hyponatremia in Heart Failure: Pathogenesis and Management

Hyponatremia is a very common electrolyte abnormality, associated with poor short- and long-term outcomes in patients with heart failure (HF). Two opposite processes can result in hyponatremia in this setting: Volume overload with dilutional hypervolemic hyponatremia from congestion, and hypovolemic hyponatremia from excessive use of natriuretics. These two conditions require different therapeutic approaches. While sodium in the form of normal saline can be lifesaving in the second case, the same treatment would exacerbate hyponatremia in the first case. Hypervolemic hyponatremia in HF patients is multifactorial and occurs mainly due to the persistent release of arginine vasopressin (AVP) in the setting of ineffective renal perfusion secondary to low cardiac output. Fluid restriction and loop diuretics remain mainstay treatments for hypervolemic/dilutional hyponatremia in patients with HF. In recent years, a few strategies, such as AVP antagonists (Tolvaptan, Conivaptan, and Lixivaptan), and hypertonic saline in addition to loop diuretics, have been proposed as potentially promising treatment options for this condition. This review aimed to summarize the current literature on pathogenesis and management of hyponatremia in patients with HF.

The prognostic significance of serum sodium in a population undergoing cardiac resynchronisation therapy

PURPOSE

To determine the prognostic implications of changes towards hyponatremia at varying time-points in the treatment of patients undergoing cardiac resynchronisation therapy (CRT).

METHODS

A retrospective series of 249 patients was studied from 2002 to 2013. The population was categorized on the basis of serum sodium profile at baseline, at 1 month and at 6 month follow up visits following successful CRT implantation. The composite endpoint was all-cause mortality and heart failure hospitalisation (defined by the need for intravenous diuretic therapy) following CRT implantation.

RESULTS

A total of 249 patients (67.8±12.5 years; NYHA class III/IV 75; LVEF 27.2±8.8%) were followed up for a median of 5.5 years. Hyponatremia at baseline, 1 month or 6 months follow up did not predict the composite endpoint. 26% of patients showed hyponatremia at baseline prior to CRT implantation, while it was present in 19.9% of patients 1 month (p=0.003) and in 16% (p<0.001) 6 months after CRT implantation. There was a significantly worse outcome for those patients who developed hyponatremia 6 months after CRT implantation. In multivariate analysis, the intake of loop diuretics (HR 1.76 [1.04-2.95], p=0.03) and renal impairment (urea>7.0mmol/l) (HR 1.61 [1.05-2.46], p=0.03) at baseline were associated with an increased risk of unplanned heart failure hospitalisation and all-cause mortality after CRT implantation.

CONCLUSIONS

A change towards hyponatremia when observed 6 months after CRT implantation may predict a worse clinical outcome. Additionally, renal impairment and higher diuretic doses are associated with an increased risk of mortality in the population analysed.

Impact of Ultrafiltration on Serum Sodium Homeostasis and its Clinical Implication in Patients With Acute Heart Failure, Congestion, and Worsening Renal Function

BACKGROUND

The relationship between changes in serum sodium with clinical events in acute heart failure patients using different decongestive events has not been investigated. This study aimed to describe changes in serum sodium levels during decongestion therapy in patients receiving stepped pharmacological therapy versus ultrafiltration.

METHODS AND RESULTS

We studied 188 patients who were enrolled in the CARRESS-HF trial (Cardiorenal Rescue Study in Acute Decompensated Heart Failure). Treatment-induced hyponatremia was defined as admission normonatremia (≥135 mEq/L) with a subsequent decrease (<135 mEq/L) during hospitalization. Patients treated with ultrafiltration had significantly lower sodium levels than those with conventional treatment at days 1, 4, and 7 (all P<0.01), whereas those at day 30 were similar between the groups. Changes in sodium levels in patients with ultrafiltration were negatively correlated to those in serum creatinine and plasma renin activity. The incidence of treatment-induced hyponatremia was significantly higher in the ultrafiltration group than those receiving conventional treatment (P=0.002). Although patients with discharge hyponatremia had a higher risk for composite end point of all-cause death, rehospitalization, or unscheduled hospital visit in comparison to those without (adjusted hazard ratio, 2.01; 95% confidence interval, 1.09-3.70; P=0.025), the risk was comparable between patients with treatment-induced hyponatremia and those who did not experience any hyponatremia (adjusted hazard ratio, 0.99; 95% confidence interval, 0.50-1.96; P=0.99).

CONCLUSIONS

Fluid removal by ultrafiltration was associated with a decrease in serum sodium levels compared with diuretic treatment but returned to baseline levels at day 30. Discharge hyponatremia but not treatment-induced hyponatremia was associated with worse clinical outcomes.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00608491.

Implications of Serum Chloride Homeostasis in Acute Heart Failure (from ROSE-AHF)

Lower serum chloride (Cl) levels are strongly associated with increased long-term mortality after admission for acute heart failure (AHF). However, the therapeutic implications of serum Cl levels during AHF are unknown. We sought to determine the short-term clinical response and postdischarge outcomes associated with serum Cl levels in AHF. Serum Cl was measured at randomization (n = 358) and during hospitalization from patients with AHF in the Renal Optimization Strategies Evaluation in Acute Heart Failure trial. Outcomes included diuretic response and renal function at 72 hours and death and rehospitalization at 60 and 180 days. Baseline Cl tertiles were 84 to 98; 99 to 102; and 103 to 117 meq/l. Baseline Cl level was associated with diuretic efficiency (p <0.001) but not change in cystatin C (p = 0.30) at 72 hours and was associated with 60-day death (hazard ratio [HR] 0.86, p = 0.029), 60-day death and rehospitalization (HR 0.90, p = 0.01), and 180-day death (HR 0.91, p = 0.049). These associations were attenuated with additional adjustment for loop diuretic dose (p >0.05). Chloride change correlated with weight change (ρ 0.18, p = 0.001), cystatin C change (ρ -0.35, p <0.001), and cumulative sodium excretion (ρ -0.21, p <0.001) but was not associated with any clinical outcomes (p >0.05 for all). In conclusion, serum Cl levels in AHF were inversely associated with loop diuretic response and were prognostic. However, changes in Cl levels were associated with parameters of decongestion but not with clinical outcomes.

Prognostic Role of Serum Chloride Levels in Acute Decompensated Heart Failure

BACKGROUND

Acute decompensated heart failure (ADHF) can be complicated by electrolyte abnormalities, but the major focus has been concentrated on the clinical significance of serum sodium levels.

OBJECTIVES

This study sought to determine the prognostic significance of serum chloride levels in relation to serum sodium levels in patients with ADHF.

METHODS

We reviewed 1,318 consecutive patients with chronic heart failure admitted for ADHF to the Cleveland Clinic between July 2008 and December 2013. We also validated our findings in an independent ADHF cohort from the University of Pennsylvania (n = 876).

RESULTS

Admission serum chloride levels during hospitalization for ADHF were independently and inversely associated with long-term mortality (hazard ratio [HR] per unit change: 0.94; 95% confidence interval [CI]: 0.92 to 0.95; p < 0.001). After multivariable risk adjustment, admission chloride levels remained independently associated with mortality (HR per unit change: 0.93; 95% CI: 0.90 to 0.97; p < 0.001) in contrast to admission sodium levels, which were no longer significant (p > 0.05). Results were similar in the validation cohort in unadjusted (HR per unit change for mortality risk within 1 year: 0.93; 95% CI: 0.91 to 0.95; p < 0.001) and multivariable risk-adjusted analysis (HR per unit change for mortality risk within 1 year: 0.95; 95% CI: 0.92 to 0.99; p = 0.01).

CONCLUSIONS

These observations in a contemporary advanced ADHF cohort suggest that serum chloride levels at admission are independently and inversely associated with mortality. The prognostic value of serum sodium in ADHF was diminished compared with chloride.

Association of Hypocalcemia With Mortality in Hospitalized Patients With Heart Failure and Chronic Kidney Disease

BACKGROUND

Chronic kidney disease--mineral and bone disorders (CKD-MBD) are associated with vascular calcification and abnormal electrolytes that lead to cardiovascular disease and mortality. CKD-MBD is identified by imbalances in serum calcium (Ca), phosphate, and parathyroid hormone (PTH). Although the relation of phosphate and PTH with the prognosis of HF patients has been reported, the association of Ca with prognosis in patients with heart failure (HF) and CKD remains unclear.

METHODS AND RESULTS

We examined 191 patients admitted for HF and CKD (estimated glomerular filtration rate <60 mL min(-1) 1.73 m(-2)), and they were divided into 2 groups based on levels of corrected Ca: low Ca (Ca <8.4 mg/dL; n = 32) and normal-high Ca (8.4 ≤Ca; n = 159). We compared laboratory and echocardiographic findings, as well as followed cardiac and all-cause mortality. The low-Ca group had 1) higher levels of alkaline phosphatase (308.9 vs. 261.0 U/L; P = .026), 2) lower levels of 1,25-dihydroxy vitamin D (26.1 vs. 45.0 pg/mL; P = .011) and hydrogen carbonate (22.4 vs. 24.5 mmol/L; P = .031), and 3) a tendency to have a higher PTH level (87.5 vs. 58.6 pg/mL; P = .084). In contrast, left and right ventricular systolic function, estimated glomerular filtration rate, urine protein, phosphate, sodium, potassium, magnesium, and zinc did not differ between the 2 groups. In the Kaplan-Meier analysis, cardiac and all-cause mortality were significantly higher in the low-Ca group than in the normal-high-Ca group (P < .05). In the multivariable Cox proportional hazard analyses, hypocalcemia was an independent predictor of all-cause mortality in HF and CKD patients (P < .05).

CONCLUSIONS

Hypocalcemia was an independent predictor of all-cause mortality in HF and CKD patients.

Tolvaptan for the treatment of hyponatremia and hypervolemia in patients with congestive heart failure

Patients with heart failure often show increased arginine vasopressin secretion and enhanced sympathetic and renin-angiotensin-aldosterone activation, which accelerate renal water reabsorption, causing water retention and volume overload. Tolvaptan is an orally active antagonist of arginine vasopressin type 2 receptors in the collecting duct of the kidney that inhibits water reabsorption without substantially affecting the electrolyte balance. Tolvaptan in combination with conventional diuretics improves fluid retention and congestive symptoms in patients with heart failure and volume overload, with minimal effects on hemodynamics and serum potassium. Tolvaptan slightly increases serum sodium concentrations, generally within the normal range. Although it does not seem to affect long-term mortality, tolvaptan does improve short-term water retention and congestive symptoms in heart failure patients with volume overload despite the use of conventional diuretics, and is approved for this indication in Japan.

Progression of hyponatremia is associated with increased cardiac mortality in patients hospitalized for acute decompensated heart failure

BACKGROUND

Although hyponatremia during hospitalization for acute decompensated heart failure (ADHF) has been reported to correlate with poor prognosis, few studies have examined the effect of progression of hyponatremia on cardiac prognosis in ADHF patients who were normonatremic at admission.

METHODS AND RESULTS

Consecutive ADHF patients (n = 662) categorized as New York Heart Association Class III or IV were investigated retrospectively. Of these patients, 634 who survived to discharge were examined and 531 were normonatremic (serum sodium concentration [Na] ≥ 135 and ≤ 145 mmol/L) at admission. The 531 patients were divided into 2 groups: the non-developed group, who remained normonatremic at discharge (n = 455), and the developed group, who had progressed to hyponatremia (Na < 135 mmol/L) at discharge (n = 76). The cardiac event-free rate after 12 months was significantly lower in the developed group than in the non-developed group (22% vs. 71%; P < .0001). Although their baseline levels of brain natriuretic peptide and left ventricular ejection fraction were similar before discharge, the patients in the developed group exhibited higher fractional excretion of sodium and received higher doses of diuretics than did those in the non-developed group.

CONCLUSION

Our data suggest that progression to hyponatremia during hospitalization is a robust predictor of poor cardiac prognosis in ADHF patients who were normonatremic at admission.

Management of hyponatremia in heart failure: role of tolvaptan

BACKGROUND

Asymptomatic or clinically mild hyponatremia commonly occurs in the setting of heart failure, especially among elderly and severely decompensated, fluid-overloaded patients, and is associated with increased morbidity and mortality. Successful detection and treatment of hyponatremia by cardiovascular and advanced practice nurses caring for patients with heart failure are part of multidisciplinary team care. Nurses should be able to detect signs and symptoms of hyponatremia and, even when patients are asymptomatic, initiate appropriate treatment promptly to prevent complications.

PURPOSE

In this review, the epidemiology and pathophysiology of hyponatremia in heart failure, and signs and symptoms are described. In patients with heart failure, challenges involved in determining the type of hyponatremia (hypervolemic, hypovolemic, or euvolemic) and in correctly managing hyponatremia to prevent serious complications are presented. Conventional treatment options and their limitations are reviewed, and the vasopressin-receptor antagonist tolvaptan, an emerging oral therapy option, is introduced and discussed.

CONCLUSIONS

Hyponatremia is a marker of morbidity and mortality in patients with heart failure. Nurses working collaboratively with other healthcare providers must be able to recognize the condition and understand treatment options, including potential adverse effects of current and emerging therapies. One emerging therapy--tolvaptan--can be used in hypervolemic and euvolemic hyponatremic patients with heart failure to correct serum sodium level without negatively affecting renal function.

CLINICAL IMPLICATIONS

Improved nurse understanding of hyponatremia in patients with heart failure may promote nurse-initiated or nurse-facilitated detection and management, which could decrease mortality and morbidity.

Evaluation of costs associated with tolvaptan-mediated length-of-stay reduction among heart failure patients with hyponatremia in the US, based on the EVEREST trial

BACKGROUND

The Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan (EVEREST) trial showed that tolvaptan use improved heart failure (HF) signs and symptoms without serious adverse events.

OBJECTIVE

To evaluate the potential cost savings associated with tolvaptan usage among hospitalized hyponatremic HF patients.

METHODS

The Healthcare Cost and Utilization Project (HCUP) 2008 Nationwide Inpatient Sample (NIS) database was used to estimate hospital cost and length of stay (LOS), for diagnosis-related group (DRG) hospitalizations of adult (age ≥18 years) HF patients with complications and comorbidities or major complications and comorbidities. EVEREST trial data for patients with hyponatremia were used to estimate tolvaptan-associated LOS reductions. A cost offset model was constructed to evaluate the impact of tolvaptan on hospital cost and LOS, with univariate and multivariate Monte Carlo sensitivity analyses.

RESULTS

Tolvaptan use among hyponatremic EVEREST trial HF patients was associated with shorter hospital LOS than placebo patients (9.72 vs 11.44 days, respectively); 688,336 hospitalizations for HF DRGs were identified from the HCUP NIS database, with a mean LOS of 5.4 days and mean total hospital costs of $8415. Using an inpatient tolvaptan treatment duration of 4 days with a wholesale acquisition cost of $250 per day, the cost offset model estimated a LOS reduction among HF hospitalizations of 0.81 days and an estimated total cost saving of $265 per admission. Univariate and multivariate sensitivity analysis demonstrated that cost reduction associated with tolvaptan usage is consistent among variations of model variables.

CONCLUSIONS

The estimated LOS reduction and cost savings projected by the cost offset model suggest a clinical and economic benefit to tolvaptan use in hyponatremic HF patients.

STUDY LIMITATIONS

The EVEREST trial data may not generalize well to the US population. Clinical trial patient profiles and relative LOS reductions may not be applicable to real-world patient populations.

Hyponatremia and long-term outcomes in chronic heart failure--an observational study from the Duke Databank for Cardiovascular Diseases

BACKGROUND

Hyponatremia is a well known predictor of short-term outcomes in heart failure (HF); however, its impact on long-term survival in HF patients with systolic dysfunction is not well established.

METHODS AND RESULTS

Using the Duke Databank for Cardiovascular Diseases, we identified 1,045 patients with HF and systolic dysfunction undergoing cardiac catheterization from January 2000 through December 2008. The effect of hyponatremia as independent predictor of all-cause death and cardiovascular death/rehospitalization was examined using a multivariable Cox proportional regression model. Hyponatremia was present in 107/1,045 patients (10.2%). Hyponatremic patients were older, more likely to be anemic, with higher heart rate and levels of blood urea nitrogen, lower blood pressure, and more severe HF. Using an unadjusted analysis, hyponatremia was associated with higher risk of all-cause death (hazard ratio [HR] 1.89, 95% confidence interval [CI] 1.44-2.49; P < .0001) and of cardiovascular death/rehospitalization (HR 1.40, 95% CI 1.11-1.77; P = .005) at 4.5 years. When entered into a multivariable Cox model, hyponatremia remained significant for all-cause death (HR 1.42, 95% CI 1.07-1.88) and for cardiovascular death/rehospitalization (HR 1.45, 95% CI 1.14-1.86).

CONCLUSIONS

Hyponatremia is relatively common in HF patients with LV dysfunction and is independently associated with increased risk of all-cause mortality and cardiovascular mortality/rehospitalization.

Parameters of mineral metabolism predict midterm clinical outcome in end-stage heart failure patients

OBJECTIVES

We investigated to which extent disturbances in mineral metabolism predict 90-day clinical outcome in end-stage heart failure patients.

DESIGN

Among numerous biochemical parameters, we measured serum levels of sodium and magnesium, the calciotropic hormones parathyroid hormone and 1,25-dihydroxyvitamin D as well as fibroblast growth factor-23 (a phosphaturic hormone) in 305 cardiac transplant candidates. Primary endpoint was a composite of the need of mechanical circulatory support (MCS), transplantation, or death.

RESULTS

Of the study cohort, 33.4% reached the primary endpoint. In detail, 19% were transplanted (the vast majority was listed "high urgent"), 8.8% died and 5.6% received MCS implants. As determined by logistic regression analysis, all aforementioned biochemical parameters were independently related to the primary endpoint. Results did not change substantially when transplanted patients were censored. A risk score (0-5 points) was developed. Of the patients who scored 5 points 89.5% reached the primary endpoint whereas of the patients with a zero score only 3.8% reached the primary endpoint.

CONCLUSIONS

Our data demonstrate that in addition to the well-known predictive value of disturbed sodium metabolism, derangements in calcium, phosphate, and magnesium metabolism also predict midterm clinical outcome in end-stage heart failure patients.

Hyponatremia in acute decompensated heart failure: mechanisms, prognosis, and treatment options

Hyponatremia is common and is increasingly recognized as an independent prognostic marker that adversely affects morbidity and mortality in various disease states, including heart failure. In acute decompensated heart failure (ADHF), the degree of hyponatremia often parallels the severity of cardiac dysfunction and is further exacerbated by any reduction in glomerular filtration rate and arginine vasopressin dysregulation. A recent study showed that even modest improvement of hyponatremia may have survival benefits. Although management of hyponatremia in ADHF has traditionally focused on improving cardiac function and fluid restriction, the magnitude of improvement of serum sodium is fairly slow and unpredictable. In this article, we discuss the mechanisms of hyponatremia in ADHF, review its evolving prognostic significance, and evaluate the efficacy of various treatments for hyponatremia, including the recently approved vasopressin receptor antagonists for managing hyponatremia among patients hospitalized for ADHF.

Hyponatremia in heart failure: revisiting pathophysiology and therapeutic strategies

Hyponatremia is frequently encountered in patients with heart failure (HF), and its association with adverse outcomes is well-established in this population. While hyponatremia is an independent marker for severity of HF, it is not certain whether it has a causal impact on the progression of the disease. There are no universally accepted consensus guidelines regarding therapeutic strategies for HF-associated hyponatremia and volume overload; current societal guidelines do not address management of this complication. Whereas thiazide diuretics are known to induce or worsen hyponatremia in this setting through a number of mechanisms, loop diuretics can be considered a readily available first-line pharmacologic therapy. Consistent with pathophysiology of the disease and mechanisms of action of loop diuretics, available clinical evidence supports such an approach provided that patients can be closely monitored. Use of vasopressin receptor antagonists is an emerging therapeutic strategy in this setting, and the efficacy of these agents has so far been shown in a number of clinical studies. These agents can be reserved for patients with HF in whom initial appropriate loop diuretic therapy fails to improve serum sodium levels.

Arginine vasopressin receptor antagonists (vaptans): pharmacological tools and potential therapeutic agents

Arginine vasopressin (AVP) attracted attention as a potentially important neurohormonal mediator of the heart failure (HF) syndrome and hyponatremic states in humans because AVP influences renal handling of free water, vasoconstriction and myocyte biology through activation of V₂ and V₁(a) receptors. Current research is exploring V₂- and dual V₁(a)/V₂ receptor antagonism for the treatment of hyponatremia, as well as for the congestion and edema associated with chronic HF, because vasopressin receptor antagonists might offer benefits in comparison with conventional loop diuretics. The purpose of this review is to update the current status of experimental and clinical studies with available vasopressin receptor antagonists (conivaptan and tolvaptan) and their potential role in the treatment of HF and hyponatremia of multiple causes.

VRQ397 (CRAVKY): a novel noncompetitive V2 receptor antagonist

Vasopressin type 2 receptor (V2R) exhibits mostly important properties for hydroosmotic equilibrium and, to a lesser extent, on vasomotricity. Drugs currently acting on this receptor are analogs of the natural neuropeptide, arginine vasopressin (AVP), and hence are competitive ligands. Peptides that reproduce specific sequences of a given receptor have lately been reported to interfere with its action, and if such molecules arise from regions remote from the binding site they would be anticipated to exhibit noncompetitive antagonism, but this has yet to be shown for V2R. Six peptides reproducing juxtamembranous regions of V2R were designed and screened; the most effective peptide, cravky (labeled VRQ397), was characterized. VRQ397 was potent (IC(50) = 0.69 +/- 0.25 nM) and fully effective in inhibiting V2R-dependent physiological function, specifically desmopressin-L-desamino-8-arginine-vasopressin (DDAVP)-induced cremasteric vasorelaxation; this physiological functional assay was utilized to avoid overlooking interference of specific signaling events. A dose-response profile revealed a noncompetitive property of VRQ397; correspondingly, VRQ397 bound specifically to V2R-expressing cells could not displace its natural ligand, AVP, but modulated AVP binding kinetics (dissociation rate). Specificity of VRQ397 was further confirmed by its inability to bind to homologous V1 and oxytocin receptors and its inefficacy to alter responses to stimulation of these receptors. VRQ397 exhibited pharmacological permissiveness on V2R-induced signals, as it inhibited DDAVP-induced PGI(2) generation but not that of cAMP or recruitment of beta-arrestin2. Consistent with in vitro and ex vivo effects as a V2R antagonist, VRQ397 displayed anticipated in vivo aquaretic efficacy. We hereby describe the discovery of a first potent noncompetitive antagonist of V2R, which exhibits functional selectivity, in line with properties of a negative allosteric modulator.