Lower serum sodium is associated with increased short-term mortality in hospitalized patients with worsening heart failure: results from the Outcomes of a Prospective Trial of Intravenous Milrinone for Exacerbations of Chronic Heart Failure (OPTIME-CHF) study

Relation of serum sodium level to long-term outcome after a first hospitalization for heart failure with preserved ejection fraction

Hyponatremia is a predictor of adverse short-term outcomes in patients with acute heart failure (HF). The impact of hyponatremia on long-term survival in patients with HF with preserved ejection fraction (HFPEF) has not been evaluated. Our aim was to prospectively assess the impact of baseline natremia and changes in sodium level during hospitalization on 7-year outcome in 358 patients surviving a first hospitalization for HFPEF. On admission, hyponatremia (sodium <136 mEq/L) was diagnosed in 91 patients (25.4%). Baseline hyponatremia was associated with an increased risk of overall (hazard ratio [HR] 1.98, 95% confidence interval [CI] 1.50 to 2.61) and cardiovascular mortality (HR 1.92, 95% CI 1.36 to 2.73). After adjustment for covariates, the relations remained significant. Seven-year relative survival (observed/expected survival) of hyponatremic patients was lower than that of patients with normal baseline natremia (31% vs 63%). The association of sodium and risk of death appeared linear across quartiles of baseline natremia and slightly stronger at the lowest of sodium values. At discharge, 45 patients with low baseline sodium had normal natremia (49%) and 46 had persistent hyponatremia (51%). Patients with normalized natremia at discharge had excess 7-year overall mortality compared with the normonatremic group (HR 1.50, 95% CI 1.03 to 2.19). Patients with persistent hyponatremia had the lowest 7-year survival (HR 2.67, 95% CI 1.89 to 3.78). After adjustment for covariates, patients with persistent hyponatremia had an impressive increase in relative risk of overall mortality compared with patients with normal baseline natremia. In conclusion, hyponatremia is a powerful predictor of long-term mortality in patients with HFPEF. Patients with HFPEF and persistent hyponatremia are at high risk of adverse outcomes.

Disorders of sodium and water balance in hospitalized patients

PURPOSE

To review and discuss the epidemiology, contributing factors, and approach to clinical management of disorders of sodium and water balance in hospitalized patients.

SOURCE

An electronic search of the MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases and a search of the bibliographies of all relevant studies and review articles for recent reports on hyponatremia and hypernatremia with a focus on critically ill patients.

PRINCIPAL FINDINGS

Disorders of sodium and water balance are exceedingly common in hospitalized patients, particularly those with critical illness and are often iatrogenic. These disorders are broadly categorized as hypo-osmolar or hyper-osmolar, depending on the balance (i.e., excess or deficit) of total body water relative to total body sodium content and are classically recognized as either hyponatremia or hypernatremia. These disorders may represent a surrogate for increased neurohormonal activation, organ dysfunction, worsening severity of illness, or progression of underlying chronic disease. Hyponatremic disorders may be caused by appropriately elevated (volume depletion) or inappropriately elevated (SIADH) arginine vasopressin levels, appropriately suppressed arginine vasopressin levels (kidney dysfunction), or alterations in plasma osmolality (drugs or body cavity irrigation with hypotonic solutions). Hypernatremia is most commonly due to unreplaced hypotonic water depletion (impaired mental status and/or access to free water), but it may also be caused by transient water shift into cells (from convulsive seizures) and iatrogenic sodium loading (from salt intake or administration of hypertonic solutions).

CONCLUSION

In hospitalized patients, hyponatremia and hypernatremia are often iatrogenic and may contribute to serious morbidity and increased risk of death. These disorders require timely recognition and can often be reversed with appropriate intervention and treatment of underlying predisposing factors.

Physiology and pathophysiology of the vasopressinergic system

Arginine vasopressin, a hypothalamic peptide hormone, has multiple physiological functions, including body water regulation, control of blood pressure and effects on body temperature, insulin release, corticotropin release, memory and social behaviour. These functions are achieved via at least three specific G-protein-coupled vasopressin receptors. Development of specific vasopressin receptor antagonists in recent years is helping to elucidate the precise actions of vasopressin at each of these receptor types. The complex signalling and messenger processes which take place after receptor stimulation are now more clearly understood. Vasopressin dysregulation can occur in various disease processes, and a better understanding of the mechanisms underlying physiological synthesis, release and regulation of vasopressin will help in the development of therapies to treat these conditions.

Clinical predictors of in-hospital mortality in acutely decompensated heart failure-piecing together the outcome puzzle

The substantial public health impact of hospitalization for acute decompensated heart failure, from an economic and clinical perspective, has generated substantial interest in understanding predictors of risk in this syndrome. Utilization of classification and regression tree (CART) analysis on the Acute Decompensated Heart Failure National Registry (ADHERE) dataset has provided important risk stratification from readily available clinical variables. Increasingly, high-risk patients were identified by combination of blood urea nitrogen level of 43 mg/dL, serum creatinine level of 2.75 mg/dL, and systolic blood pressure less than 115 mm Hg, which were all independent predictors of high risk for in-hospital mortality. On the basis of these 3 variables, acutely decompensated heart failure patients can be readily stratified into groups at low, intermediate, and high risk for in-hospital mortality, with mortality risks ranging from 2.1% to 21.9%. Although risk stratification alone cannot improve outcomes, identification of patients at high and low risk may improve resource utilization and better focus the intensity of care according to outcome.

Hyponatremia in heart failure

Hyponatremia is the most common electrolyte abnormality found in hospitalized patients with heart failure. It may occur in patients who have hypovolemic, hypervolemic, or euvolemic state. It is usually not corrected by available therapies. It is a major predictor of prognosis, and correction of hyponatremia can be effectively accomplished by vasopressin antagonists. However, it still remains to be seen whether the normalization of serum sodium with vasopressin antagonists will also lead to an improved long-term prognosis.

Hyponatremia and hospital outcomes among patients with pneumonia: a retrospective cohort study

Background

Community-acquired (CAP) and nosocomial pneumonias contribute substantially to morbidity and hospital resource utilization. Hyponatremia, occurring in >1/4 of patients with CAP, is associated with greater disease severity and worsened outcomes.

Methods

To explore how hyponatremia is associated with outcomes in hospitalized patients with pneumonia, we analyzed a large administrative database with laboratory component from January 2004 to December 2005. Hyponatremia was defined as at least two [Na⁺] < 135 mEq/L within 24 hours of admission value.

Results

Of 7,965 patients with pneumonia, 649 (8.1%) with hyponatremia were older (72.4 ± 15.7 vs. 68.0 ± 22.0, p < 0.01), had a higher mean Deyo-Charlson Comorbidity Index Score (1.7 ± 1.7 vs. 1.6 ± 1.6, p = 0.02), and higher rates of ICU (10.0% vs. 6.3%, p < 0.001) and MV (3.9% vs. 2.3%, p = 0.01) in the first 48 hours of hospitalization than patients with normal sodium. Hyponatremia was associated with an increased ICU (6.3 ± 5.6 vs. 5.3 ± 5.1 days, p = 0.07) and hospital lengths of stay (LOS, 7.6 ± 5.3 vs. 7.0 ± 5.2 days, p < 0.001) and a trend toward increased hospital mortality (5.4% vs. 4.0%, p = 0.1). After adjusting for confounders, hyponatremia was associated with an increased risk of ICU (OR 1.58, 95% CI 1.20–2.08), MV (OR 1.75 95% CI 1.13–2.69), and hospital death (OR 1.3, 95% CI 0.90–1.87) and with increases of 0.8 day to ICU and 0.3 day to hospital LOS, and over $1,300 to total hospital costs.

Conclusion

Hyponatremia is common among hospitalized patients with pneumonia and is associated with worsened clinical and economic outcomes. Studies in this large population are needed to explore whether prompt correction of [Na⁺] may impact these outcomes.

Role of tolvaptan in acute decompensated heart failure

Acute decompensated heart failure accounts for more than 1 million hospitalizations in the USA every year. Currently, the most common treatment for symptom relief is the use of loop diuretics, despite recent concerns for potential adverse effects. With the growing understanding of the role of neurohormonal dysregulation in the pathophysiology of heart failure, there has been increasing interest in novel pharmacologic therapies targeting specific neurohormonal axes. Serum arginine vasopressin is a potent vasoconstrictor, as well as an antidiuretic, and serum concentrations are upregulated in heart failure. Tolvaptan, a vasopressin receptor antagonist, has been shown to improve diuresis and symptom relief without adversely affecting renal function, and may be a promising novel therapeutic agent in the growing population of patients with heart failure.

Prediction of mortality in patients with heart failure and systolic dysfunction

Systolic heart failure has a highly variable mortality that can be altered with medications and cardiac devices. This review focuses on recently published predictive models in heart failure. These models may help with difficult decisions such as listing for cardiac transplantation, selecting cardiac devices, and making end-of-life decisions. We discuss systolic heart failure risk models to estimate short- (30-day to 1-year) and longer-term (1- to 5-year) mortality in hospitalized and ambulatory heart failure patients.

Sensitivity of International Classification of Diseases codes for hyponatremia among commercially insured outpatients in the United States

Background

Administrative claims are a rich source of information for epidemiological and health services research; however, the ability to accurately capture specific diseases or complications using claims data has been debated. In this study, the authors examined the validity of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes for the identification of hyponatremia in an outpatient managed care population.

Methods

We analyzed outpatient laboratory and professional claims for patients aged 18 years and older in the National Managed Care Benchmark Database from Integrated Healthcare Information Services. We obtained all claims for outpatient serum sodium laboratory tests performed in 2004 and 2005, and all outpatient professional claims with a primary or secondary ICD-9-CM diagnosis code of hyponatremia (276.1).

Results

A total of 40,668 outpatient serum sodium laboratory results were identified as hyponatremic (serum sodium < 136 mmol/L). The sensitivity of ICD-9-CM codes for hyponatremia in outpatient professional claims within 15 days before or after the laboratory date was 3.5%. Even for severe cases (serum sodium ≤ 125 mmol/L), sensitivity was < 30%. Specificity was > 99% for all cutoff points.

Conclusion

ICD-9-CM codes in administrative data are insufficient to identify hyponatremia in an outpatient population.

Mechanical circulatory support devices for acute heart failure syndromes: considerations for clinical trial design

Mechanical circulatory support (MCS) devices are a guideline-recommended treatment option for a small subset of advanced heart failure patients. MCS has the potential to become more prominent in the management of Acute Heart Failure Syndromes (AHFS) as device technology advances and as clinical trials consistently discover neutral or harmful effects with pharmacologic therapies hypothesized to be beneficial in this population. While it is now possible to identify AHFS patients who are at high risk of death, the therapeutic options available to improve their long-term outcomes are limited. MCS therapy in this population offers a "bridge to recovery" strategy; these patients may have viable myocardium that responds favorably to the influence of MCS on neurohormones, cytokines, and/or reverse remodeling. Patients at high risk for mortality who have a substantial likelihood of benefiting from MCS can be easily identified using standard clinical criteria developed from large observational databases. MCS technology is rapidly evolving, and risks related to implantation are declining. It is evident that rigorous clinical trial testing of the potential risks, benefits, and economic implications of MCS in patients with AHFS will need to be conducted before the "routine" application of this aggressive therapy. This paper examines the rationale for conducting trials of MCS devices in patients with AHFS, and it explores considerations for patient selection and appropriate endpoints. This manuscript was generated from discussions on this issue during the third international meeting of the International Working Group on AHFS held in Washington, DC, April 8-9, 2006.

Epidemiology, clinical and economic outcomes of admission hyponatremia among hospitalized patients

BACKGROUND

Hyponatremia, the most frequent electrolyte derangement identified among hospitalized patients, is associated with worsened outcomes in patients with pneumonia, heart failure and other disorders.

RESEARCH DESIGN AND METHODS

We performed a retrospective cohort study of hospitalized patients to quantify the attributable influence of admission hyponatremia on hospital costs and outcomes. Data were derived from a large administrative database with laboratory components, representing 198,281 discharges from 39 US hospitals from January 2004 to December 2005. Hyponatremia was defined as admission serum [Na(+)]<135 mEq/L.

RESULTS

The incidence of hyponatremia at admission was 5.5% (n=10,899). Patients with hyponatremia were older (65.7+/-19.6 vs. 61.5+/-21.8, p<0.001) and had a higher Deyo-Charlson Comorbidity Index score (1.8+/-2.1 vs. 1.3+/-1.8, p<0.001) than those with normal [Na(+)]. A higher proportion of hyponatremic patients required intensive care unit (ICU) (17.3% vs. 10.9%, p<0.001) and mechanical ventilation (MV) (5.0% vs. 2.8%, p<0.001) within 48 hours of hospitalization. Hospital mortality (5.9% vs. 3.0%, p<0.001), mean length of stay (HLOS, 8.6+/-8.0 vs. 7.2+/-8.2 days, p<0.001) and costs ($16,502+/-$28,984 vs. $13,558+/-$24,640, p<0.001) were significantly greater among patients with hyponatremia than those without. After adjusting for confounders, hyponatremia was independently associated with an increased need for ICU (OR 1.64, 95% CI 1.56-1.73) and MV (OR 1.68, 95% CI 1.53-1.84), and higher hospital mortality (OR 1.55, 95% CI 1.42-1.69). Hyponatremia also contributed an increase in HLOS of 1.0 day and total hospital costs of $2,289.

CONCLUSIONS

Hyponatremia is common at admission among hospitalized patients and is independently associated with a 55% increase in the risk of death, substantial hospital resource utilization and costs. Potential for bias inherent in the retrospective cohort design is the main limitation of our study. Studies are warranted to explore how prompt normalization of [Na(+)] may impact these outcomes.

Hyponatraemia in acute heart failure is a marker of increased mortality but not when associated with hyperglycaemia

Previous studies suggest that hyponatraemia is a marker of neurohormonal activation and increased mortality in patients with acute heart failure (AHF). Although diabetes is a common co-morbidity in heart failure, no prior study has considered the impact of serum glucose on this relationship.

METHODS

Over four consecutive months we prospectively registered all patients admitted due to AHF. Sodium and glucose levels were determined immediately upon admission. Patients were followed through admission and for the next 6 months. Of 342 patients enrolled, complete data were available for 331 patients.

RESULTS

Hyponatraemia (sodium <135 mmol/L) was detected in 22% of patients. However, 47% of patients with hyponatraemia had concomitant hyperglycaemia (glucose level >11 mmol/L). Hyponatraemia was associated with increased 6-month mortality (21 vs. 8%, p=0.002). This association was restricted to patients who had hyponatraemia without concomitant hyperglycaemia. The 6-month mortality of patients with and without hyponatraemia was 11% versus 10% (p=0.87) when hyperglycaemia was present versus 29% and 7% (p<0.001) when hyperglycaemia was absent.

CONCLUSIONS

In this preliminary study, hyperglycaemia-associated hyponatraemia was present in a significant proportion of patients admitted with AHF. In patients with hyperglycaemia, hyponatraemia had no prognostic significance, whereas in patients without hyperglycaemia, hyponatraemia remained a powerful predictor of mortality. These results need confirmation in a larger study.

Overview of emerging pharmacologic agents for acute heart failure syndromes

BACKGROUND

Several therapies commonly used for the treatment of acute heart failure syndromes (AHFS) present some well-known limitations and have been associated with an early increase in the risk of death. There is, therefore, an unmet need for new pharmacologic agents for the early management of AHFS that may improve both short- and long-term outcomes.

AIM

To review the recent evidence on emerging pharmacologic therapies in AHFS.

METHODS

A systematic search of peer-reviewed publications was performed on MEDLINE, EMBASE and Clinical Trials.gov from January 1990 to August 2007. The results of unpublished or ongoing trials were obtained from presentations at national and international meetings and pharmaceutical industry releases. Bibliographies from these references were also reviewed, as were additional articles identified by content experts.

RESULTS

Cumulative data from large studies and randomised trials suggest that therapies with innovative mechanisms of action may safely and effectively reduce pulmonary congestion or improve cardiac performance in AHFS patients.

CONCLUSION

Some investigational agents for the management of AHFS are able to improve haemodynamics and/or clinical status. In spite of these promising findings, no new agent has demonstrated a clear benefit in terms of long-term clinical outcomes compared to placebo or conventional therapies.

Vasopressin-receptor antagonists in heart failure

PURPOSE

The role of arginine vasopressin in heart failure and the use of vasopressin receptor antagonists in the treatment of heart failure are reviewed.

SUMMARY

Arginine vasopressin (AVP) functions in the regulation of plasma osmolarity and blood pressure. In heart failure, AVP worsens heart failure by causing vasoconstriction of arteries and veins, potentially contributing to remodeling of the left ventricle and causing fluid retention and worsening of hyponatremia. Two V(2)-receptor antagonists, tolvaptan and lixivaptan, and one combined V(1a)- and V(2)-receptor antagonist, conivaptan, have shown promise for use in patients with heart failure. All three agents have been shown to increase free water excretion and increase serum sodium levels while maintaining serum potassium levels. They have not been shown to decrease renal function or the glomerular filtration rate and are well tolerated, with thirst being the major adverse effect during clinical trials. Because of their effects on sodium, vasopressin antagonists need to be carefully monitored to ensure that serum sodium levels do not increase too quickly and put the patient at risk for overcorrection or osmotic demyelination syndrome. In addition, patients need to be monitored for signs of dehydration secondary to increased urine excretion. To date, studies have not consistently shown improvements in patient symptoms or weight reduction. However, early data suggest that at least one agent, tolvaptan, does not alter mortality.

CONCLUSION

Based on data from available clinical trials, vasopressin antagonists may offer a new treatment option for patients with congestive heart failure. However, these agents do not currently appear to delay the progression of heart failure or decrease mortality.

Non-peptide arginine-vasopressin antagonists: the vaptans

Arginine-vasopressin is a hormone that plays an important part in circulatory and water homoeostasis. The three arginine-vasopressin-receptor subtypes--V1a, V1b, and V2--all belong to the large rhodopsin-like G-protein-coupled receptor family. The vaptans are orally and intravenously active non-peptide vasopressin receptor antagonists that are in development. Relcovaptan is a selective V1a-receptor antagonist, which has shown initial positive results in the treatment of Raynaud's disease, dysmenorrhoea, and tocolysis. SSR-149415 is a selective V1b-receptor antagonist, which could have beneficial effects in the treatment of psychiatric disorders. V2-receptor antagonists--mozavaptan, lixivaptan, satavaptan, and tolvaptan--induce a highly hypotonic diuresis without substantially affecting the excretion of electrolytes (by contrast with the effects of diuretics). These drugs are all effective in the treatment of euvolaemic and hypervolaemic hyponatraemia. Conivaptan is a V1a/V2 non-selective vasopressin-receptor antagonist that has been approved by the US Food and Drug Administration as an intravenous infusion for the inhospital treatment of euvolaemic or hypervolaemic hyponatraemia.

Hyponatremia predicts right heart failure and poor survival in pulmonary arterial hypertension

RATIONALE

Hyponatremia is associated with decompensated heart failure and poor prognosis in patients with left ventricular systolic dysfunction.

OBJECTIVES

We sought to determine if hyponatremia is associated with right heart failure and worse prognosis in patients with pulmonary arterial hypertension (PAH).

METHODS

We prospectively followed 40 patients with PAH and examined the relationship between serum sodium and right heart function as well as survival.

MEASUREMENTS AND MAIN RESULTS

Subjects with hyponatremia (Na < or = 136 mEq/L) were more symptomatic (11/13 World Health Organization [WHO] class III/IV vs. 12/27 WHO class III/IV; P = 0.02), had more peripheral edema (69 vs. 26%; P = 0.009), and had higher hospitalization rates (85 vs. 41%; P = 0.009) than normonatremic subjects. Hyponatremic subjects had higher right atrial pressure (14 +/- 6 vs. 9 +/- 3 mm Hg; P < 0.001), lower stroke volume index (21 +/- 7 vs. 32 +/- 10 ml/m(2); P < 0.01), larger right ventricular:left ventricular area ratio (1.8 +/- 0.4 vs. 1.3 +/- 0.4; P < 0.001), and lower tricuspid annular plane systolic excursion (1.4 +/- 0.3 vs. 2.0 +/- 0.6 cm; P = 0.001), despite similar mean pulmonary artery pressure (49 +/- 10 vs. 47 +/- 12 mm Hg; P = 0.60). The 1- and 2-year survival estimates were 93% (95% confidence interval [CI], 73-98%) and 85% (95% CI, 65-94%), and 38% (95% CI, 14-63%) and 15% (95% CI, 2-39%) for normonatremic and hyponatremic subjects, respectively (log-rank chi(2) = 25.19, P < 0.001). The unadjusted risk of death (hazard ratio) in hyponatremic compared with normonatremic subjects was 10.16 (95% CI, 3.42-30.10, P < 0.001). Hyponatremia predicted outcome after adjusting for WHO class, diuretic use, as well as right atrial pressure and cardiac index.

CONCLUSIONS

Hyponatremia is strongly associated with right heart failure and poor survival in PAH.

Contemporary trends in the pharmacological and extracorporeal management of heart failure: a nephrologic perspective

Heart failure and chronic kidney disease share a number of risk factors and pathophysiological pathways. These 2 pathological processes coexist in large numbers of patients. Whereas the presence of chronic kidney disease in patients with heart failure adversely influences their survival, cardiovascular disease is the major cause of mortality in individuals with chronic kidney disease. The management of heart failure by cardiologists has recently expanded from pharmacological treatment to extracorporeal strategies; the interaction between (and concurrent use of) these approaches traditionally has been part of nephrology care and training. The purpose of this review is to explore these management strategies from a nephrologic standpoint and cover the pathophysiology of diuretic resistance, new pharmaceutical strategies to induce natriuresis or aquaresis, and the physiological basis and theoretical advantages of fluid removal by nontraditional peritoneal or hemofiltration approaches. This review also focuses on the technical features, safety, and potential risks of dedicated ultrafiltration devices that do not require dialysis staff or facilities and that are now readily available to nonnephrologists.

Hyponatremia and vasopressin antagonism in congestive heart failure

In a national heart failure registry, hyponatremia (serum sodium < 130 mEq/L) was initially reported in 5% of patients and considered a risk factor for increased morbidity and mortality. In a chronic heart failure study, serum sodium level on admission predicted an increased length of stay for cardiovascular causes and increased mortality within 60 days of discharge. Hyponatremia in patients with congestive heart failure (CHF) is associated with a higher mortality rate. Also, by monitoring and increasing serum sodium levels during hospitalization for CHF, patient outcomes may improve. This review describes the pathophysiology of hyponatremia in relation to CHF, including the mechanism of action of vasopressin receptors in the kidney, and assesses the preclinical and clinical trials of vasopressin receptor antagonists--agents recently developed to treat hyponatremia. In hospitalized patients with CHF, hyponatremia plays a major role in poor outcomes. Vasopressin receptor antagonists have been shown to be safe and effective in clinical trials in patients with hyponatremia.

Medical costs of abnormal serum sodium levels

An abnormal serum sodium level is the most common electrolyte disorder in the United States and can have a significant impact on morbidity and mortality. The direct medical costs of abnormal serum sodium levels are not well understood. The impact of hyponatremia and hypernatremia on 6-mo and 1-yr direct medical costs was examined by analyzing data from the Integrated HealthCare Information Services National Managed Care Benchmark Database. During the period analyzed, there were 1274 patients (0.8%) with hyponatremia (serum sodium <135 mmol/L), 162,829 (97.3%) with normal serum sodium levels, and 3196 (1.9%) with hypernatremia (>145 mmol/L). Controlling for age, sex, region, and comorbidities, hyponatremia was a significant independent predictor of costs at 6 mo (41.2% increase in costs; 95% confidence interval, 30.3% to 53.0%) and at 1 yr (45.7% increase; 95% confidence interval, 34.2% to 58.2%). Costs associated with hypernatremia were not significantly different from those incurred by patients with normal serum sodium. In conclusion, hyponatremia is a significant independent predictor of 6-mo and 1-yr direct medical costs.

Normal-sodium diet compared with low-sodium diet in compensated congestive heart failure: is sodium an old enemy or a new friend?

The aim of the present study was to evaluate the effects of a normal-sodium (120 mmol sodium) diet compared with a low-sodium diet (80 mmol sodium) on readmissions for CHF (congestive heart failure) during 180 days of follow-up in compensated patients with CHF. A total of 232 compensated CHF patients (88 female and 144 male; New York Heart Association class II–IV; 55–83 years of age, ejection fraction <35% and serum creatinine <2 mg/dl) were randomized into two groups: group 1 contained 118 patients (45 females and 73 males) receiving a normal-sodium diet plus oral furosemide [250–500 mg, b.i.d. (twice a day)]; and group 2 contained 114 patients (43 females and 71 males) receiving a low-sodium diet plus oral furosemide (250–500 mg, b.i.d.). The treatment was given at 30 days after discharge and for 180 days, in association with a fluid intake of 1000 ml per day. Signs of CHF, body weight, blood pressure, heart rate, laboratory parameters, ECG, echocardiogram, levels of BNP (brain natriuretic peptide) and aldosterone levels, and PRA (plasma renin activity) were examined at baseline (30 days after discharge) and after 180 days. The normal-sodium group had a significant reduction (P<0.05) in readmissions. BNP values were lower in the normal-sodium group compared with the low sodium group (685±255 compared with 425±125 pg/ml respectively; P<0.0001). Significant (P<0.0001) increases in aldosterone and PRA were observed in the low-sodium group during follow-up, whereas the normal-sodium group had a small significant reduction (P=0.039) in aldosterone levels and no significant difference in PRA. After 180 days of follow-up, aldosterone levels and PRA were significantly (P<0.0001) higher in the low-sodium group. The normal-sodium group had a lower incidence of rehospitalization during follow-up and a significant decrease in plasma BNP and aldosterone levels, and PRA. The results of the present study show that a normal-sodium diet improves outcome, and sodium depletion has detrimental renal and neurohormonal effects with worse clinical outcome in compensated CHF patients. Further studies are required to determine if this is due to a high dose of diuretic or the low-sodium diet.

A propensity-matched study of the association of low serum potassium levels and mortality in chronic heart failure

AIMS

Potassium homeostasis is essential for normal myocardial function, and low serum potassium may cause fatal arrhythmias. However, the association of low potassium and long-term mortality and morbidity in heart failure (HF) is largely unknown.

METHODS AND RESULTS

We studied 6845 HF patients in the Digitalis Investigation Group trial with serum potassium levels < or =5.5 mEq/L. Of these, 1189 had low potassium (<4 mEq/L). Propensity scores for low potassium were calculated for each patient and were used to match 1187 low-potassium patients with 1187 normal-potassium (4-5.5 mEq/L) patients. Effects of low potassium on outcomes were assessed using matched Cox regression analyses. All-cause mortality occurred in 379 (rate, 1103/10 000 person-years) normal-potassium and 441 (rate, 1330/10 000 person-years) low-potassium patients, respectively, during 3437 and 3315 years of follow-up [hazard ratio (HR), 1.25; 95% confidence interval (CI), 1.07-1.46; P = 0.006]. Cardiovascular mortality occurred in 297 (864/10 000 person-years) normal-potassium and 356 (1074/10 000 person-years) low-potassium patients (HR, 1.27; 95% CI, 1.06-1.51; P = 0.009). Cardiovascular hospitalization occurred in 610 (rate, 2553/10 000 person-years) normal-potassium and 637 (rate, 2855/10 000 person-years) low-potassium patients (HR, 1.13; 95% CI, 0.99-1.29; P = 0.082).

CONCLUSION

In a cohort of ambulatory chronic systolic and diastolic HF patients who were balanced in all measured baseline covariates, serum potassium <4 mEq/L was associated with increased mortality, with a trend towards increased hospitalization.

Improvement in hyponatremia during hospitalization for worsening heart failure is associated with improved outcomes: insights from the Acute and Chronic Therapeutic Impact of a Vasopressin Antagonist in Chronic Heart Failure (ACTIV in CHF) trial

BACKGROUND

Hyponatremia predicts poor outcome in patients with acute heart failure syndromes. This study evaluated the relationship between baseline serum sodium, change in serum sodium, and 60-day mortality in hospitalized heart failure patients.

METHODS

A post-hoc analysis of the ACTIV in CHF trial was performed. ACTIV in CHF randomized 319 patients hospitalized for worsening heart failure to placebo or one of three tolvaptan doses. Cox proportional hazards regression-analysis was used to explore the relationship between baseline hyponatremia, sodium change during the hospitalization, and 60-day mortality.

RESULTS

Hyponatremia was observed in 69 patients (21.6%). After covariate adjustment, baseline hyponatremia was a statistically significant predictor of 60-day mortality (P = 0.0016). Follow-up serum sodium data were available in 68 patients. At hospital discharge, 45 of 68 (66.2%) hyponatremic patients had improvements in serum sodium levels (> or = 2 mmol/l). Hyponatremic patients with a serum sodium improvement had a mortality rate of 11.1% at 60 days post discharge, compared with a 21.7% mortality rate in those showing no improvement. After covariate adjustment, change in serum sodium was a statistically significant predictor of 60-day mortality (HR: 0.736, 95% CI: 0.569-0.952 for each 1-mmol/l increase in serum sodium from baseline).

CONCLUSIONS

Serum sodium improvements during hospitalization for heart failure were associated with improved survival at 60 days.

Management of acute decompensated heart failure

Acute decompensated heart failure is the most common cause for hospitalization among patients over 65 years of age. It may result from new onset of ventricular dysfunction or, more typically, exacerbation of chronic heart failure symptoms. In-hospital mortality remains high for both systolic and diastolic forms of the disease. Therapy is largely empirical as few randomized, controlled trials have focused on this population and consensus practice guidelines are just beginning to be formulated. Treatment should be focused upon correction of volume overload, identifying potential precipitating causes, and optimizing vasodilator and beta-adrenergic blocker therapy. The majority of patients (>90%) will improve without the use of positive inotropic agents, which should be reserved for patients with refractory hypotension, cardiogenic shock, end-organ dysfunction, or failure to respond to conventional oral and/or intravenous diuretics and vasodilators. The role of aldosterone antagonists, biventricular pacing, and novel pharmacological agents including vasopressin antagonists, endothelin blockers, and calcium-sensitizing agents is also reviewed.

Acute heart failure syndromes: clinical scenarios and pathophysiologic targets for therapy

Acute heart failure syndromes (AHFS) represent the most common discharge diagnosis in patients over age 65 years, with an exceptionally high mortality and readmission rates at 60-90 days. Recent surveys and registries have generated important information concerning the clinical characteristics of patients with AHFS and their prognosis. Most patients with AHFS present either with normal systolic blood pressure or elevated blood pressure. Patients who present with elevated systolic blood pressure usually have pulmonary congestion, a relatively preserved left ventricular ejection fraction (LVEF), are often elderly women, and their symptoms develop typically and abruptly. Patients with normal systolic blood pressure present with systemic congestion, reduced LVEF, are usually younger with a history of chronic HF, and have symptoms that develop gradually over days or weeks. In addition to the abnormal hemodynamics (increase in pulmonary capillary wedge pressure and/or decrease in cardiac output) that characterize patients with AHFS, myocardial injury, which may be related to a decrease in coronary perfusion and/or further activation of neurohormones and renal dysfunction, probably contributes to short-term and post-discharge cardiac events. Patients with AHFS also have significant cardiac and noncardiac underlying conditions that contribute to the pathogenesis of AHFS, including coronary artery disease (ischemia, hibernating myocardium, and endothelial dysfunction), hypertension, atrial fibrillation, and type 2 diabetes mellitus. Therefore, the targets of therapy for AHFS should be not only to improve symptoms and hemodynamics but also to preserve or improve renal function, prevent myocardial damage, modulate neurohumoral and inflammatory activation, and to manage other comorbidities that may cause and/or contribute to the progression of this syndrome.

The role of plasma biomarkers in acute heart failure. Serial changes and independent prognostic value of NT-proBNP and cardiac troponin-T

AIMS

Brain natriuretic peptide (BNP), NT-proBNP and troponins are useful for the assessment of patients with heart failure. Few data exist about their serial changes and their prognostic value in patients with acute heart failure (AHF).

METHODS AND RESULTS

NT-proBNP and troponin-T plasma levels were measured at baseline, after 6, 12, 24, 48 h and at discharge in 116 consecutive patients with AHF and no evidence of acute coronary syndrome. NT-proBNP levels were 4421 pg/mL at baseline, declined after 24 h and reached their nadir at 48 h (2703 pg/mL). Troponin-T was detectable in 48% of patients. During a median follow-up of 184 days, 52 patients died or had a non-fatal cardiovascular hospitalisation. At a multivariable analysis including clinical and echo-Doppler variables, NT-proBNP plasma levels at discharge, detectable troponin-T plasma levels, and NYHA class at discharge were the only independent prognostic factors.

CONCLUSION

In patients with AHF, NT-proBNP levels decline 24 h after the initiation of intravenous therapy and troponin-T is detectable in 48% of cases. NT-proBNP levels at discharge, detectable troponin-T levels, NYHA class and serum sodium have independent prognostic value.

A single health status question had important prognostic value among outpatients with chronic heart failure

OBJECTIVE

Health status is an important marker of the impact of disease on function among patients with chronic heart failure (CHF). However, the prognostic value of CHF-specific health status on long-term mortality has not been adequately evaluated. Our objective was to assess CHF-specific health status and 5-year mortality among outpatients with CHF.

STUDY DESIGN AND SETTING

We analyzed data from 494 Veterans Affairs outpatients with diagnoses of CHF and objective evidence of left ventricular dysfunction who enrolled in a quality improvement intervention. We extracted information about comorbid diagnoses, severity of illness (Charlson index), health care utilization, drug therapy, laboratory, and vital sign data along with generic and CHF-specific health status. We then identified multivariate correlates of subsequent mortality at 5 years.

RESULTS

Five-year mortality was 44%. Age (chi2=26.1, hazard ratio [HR]=1.63, confidence interval [CI]: 1.35, 1.97; P<0.0001) and Charlson index (chi2=12.9, HR=1.39, CI: 1.16, 1.67; P=0.0003) were significantly associated with 5-year mortality. Controlling for clinical, lab, medication, and administrative data, a single-item assessing change in CHF-specific health status was independently associated with 5-year mortality (chi2=11.4, HR=0.87, CI: 0.80, 0.94, P=0.0007).

CONCLUSIONS

Given the strength of the association with mortality, health care providers should routinely assess this single-item change in health status among outpatients with CHF to identify higher risk patients and guide therapy.

Assessment of the efficacy and safety of intravenous conivaptan in euvolemic and hypervolemic hyponatremia

BACKGROUND

Most cases of hyponatremia--serum sodium concentration ([Na+]) < 135 mEq/l (< 135 mM)--are associated with an elevated plasma arginine vasopressin level. This study investigated the efficacy and tolerability of intravenous conivaptan (YM087), a vasopressin V1A/V2-receptor antagonist, in treating euvolemic and hypervolemic hyponatremia.

METHODS

Eighty-four hospitalized patients with euvolemic or hypervolemic hyponatremia (serum [Na+] 115 to < 130 mEq/l) were randomly assigned to receive intravenous placebo or conivaptan administered as a 30-min, 20-mg loading dose followed by a 96-hour infusion of either 40 or 80 mg/day. The primary efficacy measure was change in serum [Na+], measured by the baseline-adjusted area under the [Na+]-time curve. The secondary measures included time from first dose to a confirmed > or = 4 mEq/l serum [Na+] increase, total time patients had serum [Na+] > or = 4 mEq/l higher than baseline, change in serum [Na+] from baseline to the end of treatment, and number of patients with a confirmed > or = 6 mEq/l increase in serum [Na+] or normal [Na+] (> or = 135 mEq/l).

RESULTS

Both conivaptan doses increased area under the [Na+]-time curve during the 4-day treatment (p < 0.0001 vs. placebo). From baseline to the end of treatment, the least-squares mean +/- standard error serum [Na+] increase associated with placebo was 0.8 +/- 0.8 mEq/l; with conivaptan 40 mg/day, 6.3 +/- 0.7 mEq/l; and with conivaptan 80 mg/day, 9.4 +/- 0.8 mEq/l. Conivaptan significantly improved all secondary efficacy measures (p < 0.001 vs. placebo, both doses). Conivaptan was generally well tolerated, although infusion-site reactions led to the withdrawal of 1 (3%) and 4 (15%) of patients given conivaptan 40 and 80 mg/day, respectively.

CONCLUSION

Among patients with euvolemic or hypervolemic hyponatremia, 4-day intravenous infusion of conivaptan 40 mg/day significantly increased serum [Na+] and was well tolerated.

Mortalité hospitalière et durée de séjour des patients non programmés en médecine interne: valeur pronostique de paramètres biochimiques usuels à l'admission

PURPOSE

Little is known about prognosis values of biochemical markers in internal medicine patients. We have examined retrospectively the relationship between inhospital mortality or stay duration and several biochemical markers commonly performed on admission in internal medicine patients.

METHODS

Among all stays unplanned in our department during the year 2004, we collected data about 8 blood biochemical markers (sodium, potassium, chloride, bicarbonate, anion gap, urea nitrogen, creatinin, proteins), performed between the day before and the day after admission. Mixed Cox regression models computed hazard ratios for mortality associated with biochemical markers concentration. The relationship between biochemical markers concentration and duration stay was investigated in mixed linear regression models.

RESULTS

In 2004 our department totalized 1199 unplanned stays by 1054 distinct patients (age: 69.9+/-19.2 y, women: 59.2%), among which 59 deceased during stay. Biochemical markers were available for 977 (81.5%) stays (stay duration: 17.5+/-16.0 days). Inhospital mortality was significantly associated with plasma concentration on admission of potassium, proteins, anion gap and with urea nitrogen/creatinin ratio. Among survivors, duration stay was significantly associated with plasma concentration on admission of sodium, chlore, and anion gap.

CONCLUSION

Biochemical markers performed on admission need particular attention as they provide immediate information about short term prognosis of internal medicine patients.

Red cell distribution width as a novel prognostic marker in heart failure: data from the CHARM Program and the Duke Databank

OBJECTIVES

The goal of this study was to identify potentially novel laboratory markers of risk in chronic heart failure patients.

BACKGROUND

Although a variety of prognostic markers have been described in heart failure, a systematic assessment of routine laboratory values has not been reported.

METHODS

All 2,679 symptomatic chronic heart failure patients from the North American CHARM (Candesartan in Heart Failure: Assessment of Reduction in Mortality and Morbidity) program had a wide range of laboratory measures performed at a core facility, enabling us to assess the relationship between routine blood tests and outcomes using a Cox proportional hazards model. We then replicated our findings in a cohort of 2,140 heart failure patients from the Duke Databank.

RESULTS

Among 36 laboratory values considered in the CHARM program, higher red cell distribution width (RDW) showed the greatest association with morbidity and mortality (adjusted hazard ratio 1.17 per 1-SD increase, p < 0.001). Higher RDW was among the most powerful overall predictors, with only age and cardiomegaly showing a better independent association with outcome. This finding was replicated in the Duke Databank, in which higher RDW was strongly associated with all-cause mortality (adjusted hazard ratio 1.29 per 1 SD, p < 0.001), second only to age as a predictor of outcome.

CONCLUSIONS

In 2 large contemporary heart failure populations, RDW was found to be a very strong independent predictor of morbidity and mortality. Understanding how and why this marker is associated with outcome may provide novel insights into heart failure pathophysiology.

Novel strategies: challenge loop diuretics and sodium management in heart failure--Part I

This is the first of a 2-part series. This article reviews the relationships among diuretics, neurohormonal activation, renal function, fluid and Na management, the cardiorenal syndrome, and heart failure. Part II will describe novel therapies based on these relationships, focusing particularly on vasopressin antagonists and treatment using hypertonic saline solution with high-dose loop diuretics. Heart failure (HF) is a complex hemodynamic disorder characterized by chronic and progressive pump failure and fluid accumulation. Diuretics are a vital component of symptomatic management, and enhancing diuretic response in the setting of diuretic resistance is therefore pivotal. In HF patients treated with diuretics, compensatory pathophysiologic mechanisms to maintain vascular resistance, such as nonosmotic stimulation of vasopressin secretion and activation of the renin-angiotensin-aldosterone system and sympathetic nervous system, promote renal Na and water reabsorption. Thus, there remains a need to develop novel therapies for HF patients who are refractory to conventional medical treatment. The conflicting results of diuretic treatments in HF and the importance of Na management in the context of the cardiorenal syndrome and neurohormonal activation have suggested novel and counterintuitive strategies, focusing primarily on the use of vasopressin antagonists and hypertonic saline solution with high doses of loop diuretics and neurohormonal interference. The authors review the current evidence for these therapies and suggest hypothetical bases for their efficacy.

New agents for managing hyponatremia in hospitalized patients

PURPOSE

An overview of hyponatremia is provided, including its pathophysiology, clinical manifestations, signs and symptoms, and treatment, particularly with arginine vasopressin (AVP)-receptor antagonists.

SUMMARY

Hyponatremia (generally defined as a serum sodium concentration of <135 meq/L) is one of the most common electrolyte disorders in hospitalized and clinic patients. It may be caused by a number of conditions, including infections, heart disease, surgery, malignancy, and medication use. Clinical signs and symptoms such as hallucinations, lethargy, weakness, bradycardia, respiratory depression, seizures, coma, and death have been reported. Conventional treatment consists of fluid restriction and administration of hypertonic saline and pharmacologic agents, such as demeclocycline, lithium carbonate, and urea. These treatment options are often of limited effectiveness or difficult for patients to tolerate. AVP promotes the reabsorption of water in the renal collecting ducts by activation of V(2) receptors, resulting in water retention and dilution of serum solutes. The AVP-receptor antagonists, conivaptan, lixivaptan, and tolvaptan, are being studied for the treatment of hyponatremia. Conivaptan has been shown in clinical trials to increase free-water excretion and safely normalize serum sodium concentrations in patients with hyponatremia and is well tolerated. Also in clinical trials, lixivaptan and tolvaptan have safely improved serum sodium concentrations in patients with hyponatremia.

CONCLUSION

Hyponatremia is a serious health condition for which treatment should be carefully performed. As new agents for treating hyponatremia, AVP-receptor antagonists have demonstrated efficacy and safety in clinical trials and may serve as significant improvements in the current treatment options for managing this disorder.

Review of current and investigational pharmacologic agents for acute heart failure syndromes

Acute heart failure syndromes (AHFS) are a major public health problem and present a therapeutic challenge to clinicians. Commonly used agents in the treatment of AHFS include diuretics, vasodilators (eg, nitroglycerin, nitroprusside, nesiritide), and inotropes (eg, dobutamine, dopamine, milrinone). Patients admitted to hospital with AHFS and low cardiac output state (AHFS/LO) represent a subgroup with very high inhospital and postdischarge mortality rates. Most of these patients require intravenous inotropic therapy. However, the use of current intravenous inotropes has been associated with risk for hypotension, atrial and ventricular arrhythmias, and possibly increased postdischarge mortality, particularly in those with coronary artery disease. Consequently, there is an unmet need for new agents to safely improve cardiac performance (contractility and/or active relaxation) in this patient population. This article reviews a selection of current and investigational agents for the treatment of AHFS, with a main focus on the high-risk patient population with AHFS/LO.

Is there a cardiovascular rationale for the use of combined vasopressin V1a/V2 receptor antagonists?

Arginine vasopressin (AVP) signals predominantly through the V1a receptor, which subserves vasoconstriction in the peripheral circulation, and is linked directly to stimulation of myocardial hypertrophic growth factors, and the V2 receptor, the main function of which is to alter the expression of aquaporin channels in the renal collecting ducts, which leads to water retention. Agents that antagonize or block these receptors could be expected to reduce vascular tone (assuming sufficient V1a signaling is present to be causing an effect), reduce direct mitogenic signaling in the myocardium (again assuming sufficient V1a effect is present), and increase water excretion (assuming sufficient V2 signaling is present). The case for antagonizing both sets of receptors depends on the clinical situation. Pure V1a antagonists might be useful in treatment of hypertension or heart failure, but they are of little use in hyponatremia unless it is caused by heart failure. V2 antagonists would be useful in any euvolemic or hypervolemic condition associated with hyponatremia and may help produce an effective and safe diuresis independent of serum sodium when used in conjunction with loop diuretics in patients with heart failure. Selective blockade of either receptor could lead to increased signaling at the unblocked receptor sites, potentially a problematic result, especially in heart failure where disease progression is affected by increased afterload, preload, and the direct myocardial effects of neurohormonal imbalance. Therefore, a strong rationale exists for the use of combined vasopressin antagonists in patients with heart failure, particularly if the agents are used on a chronic basis.

Clinical laboratory findings associated with in-hospital mortality

The diagnostic approach and the clinical management of critically ill patients is challenging. The recognition of biomarkers related to in-hospital mortality is of importance for identification of patients at increased risk of death. Many prediction models assessing the severity of illness and likelihood of hospital survival were developed using logistic regression analyses. These models include several laboratory parameters, such as white blood cell counts, serum bilirubin, serum albumin, blood glucose, serum electrolytes and markers which reflect acid-base disturbances. Recently, several other biomarkers, including troponin, B-type natriuretic peptide (BNP), N-terminal proBNP, C-reactive protein, procalcitonin, cholesterol and coagulation related markers have emerged as clinically useful tools for risk stratification and mortality prediction of heterogeneous and more specific subgroups of critically ill patients. More investigations are required to verify whether risk stratification based on mortality-related biomarkers may translate into targeted treatment strategies to improve clinical outcome of the critical illness. Biomarkers which are related to in-hospital mortality are highlighted in the current review.

Treating hyponatremia in heart failure

Hyponatremia is common and associated with adverse outcomes in patients with congestive heart failure (CHF). In many patients who have CHF with hyponatremia, plasma arginine vasopressin (AVP) is elevated inappropriately. AVP causes water retention by interacting with V2 receptors in the renal collecting duct, leading to dilutional hyponatremia and increased ventricular preload. AVP also may contribute to pathophysiologic process in CHF by interacting with V(IA) receptors on vascular smooth muscle cells and myocytes. The potential utility of AVP antagonists--V2 antagonists and dual V(IA)/V2 antagonists--in correcting hyponatremia and relieving the congestion and edema associated with CHF is being actively explored. Combined antagonists may offer additional benefit by interfering with excessive V(IA) signaling. Unlike diuretics, which increase urine volume and electrolyte excretion, AVP antagonists of these types produce an aquaresis characterized by an increase in free water clearance concomitant with sparing of electrolytes. Studies in experimental CHF as well as preliminary clinical trials with selective and nonselective V2 antagonists have been encouraging, suggesting that these agents may hold promise for treatment of hyponatremia in CHF.

Tolvaptan: a selective vasopressin type 2 receptor antagonist in congestive heart failure

The neurohormone arginine vasopressin plays a significant role in the regulation of volume homeostasis, which is mediated via vasopressin type 2 (V2) receptors in the collecting tubules of the kidney. Diseases that are accompanied by abnormal volume homeostasis, including congestive heart failure and cirrhosis, are a frequent cause of hospital admissions and increasing healthcare costs. Recently, several nonpeptide V2 receptor antagonists have emerged as promising agents in the management of these conditions with the advantage of having no electrolyte abnormalities, neurohormonal activation or worsening renal insufficiency. Tolvaptan, a highly selective nonpeptide V2 receptor antagonist, has demonstrated an improvement in the volume status, osmotic balance and haemodynamic profile in preclinical and Phase II trials in patients with congestive heart failure and is currently undergoing testing in Phase III trials. This review discusses the evidence for the potential uses of tolvaptan, and its pharmacology and pharmacokinetics, particularly in congestive heart failure.