Risk stratification of in-hospital mortality in patients hospitalized for chronic congestive heart failure secondary to non-ischemic cardiomyopathy

Prognostic impact of abnormal sodium burden in heart failure patients with preserved ejection fraction

BACKGROUND

Sodium abnormality is common in patients with heart failure (HF) and is associated with adverse clinical outcomes. The aim of this study is to determine the impact of abnormal sodium burden on long-term mortality and hospitalization in HF with preserved ejection fraction (HFpEF).

METHODS

We analysed participants from the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial with available baseline and follow-up data (n = 1717). Abnormal sodium burden was defined as the proportion of days with abnormal sodium plasma levels (either <135 mmol/L or > 145 mmol/L). To determine the independent prognostic impact of abnormal sodium burden on the long-term clinical adverse outcomes (The primary outcome was any cause death, the secondary outcomes include cardiovascular disease death, HF hospitalization, any cause hospitalization and the primary endpoint of the original study), a multivariable Cox proportional hazard model and time-updated Cox regression model were performed.

RESULTS

Abnormal sodium burden occurred in 717 patients (41.76%). A high abnormal sodium burden was associated with 1.47 (95% CI, 1.15-1.89) higher risk with any cause mortality, 1.51 (95% CI, 1.08-2.09) higher risk with CVD death and 1.31 (95% CI, 1.02-1.69) higher risk with HF hospitalization when compared with no burden group. When sodium level changes over time were accounted for in time-updated models, abnormal sodium level was still associated with poor clinical outcomes. Diuretic and spironolactone usage did not show a statistical interaction effect on the prognostic significance.

CONCLUSIONS

In HFpEF patients, abnormal sodium burden was an independent predictor long-term any-cause mortality and HF hospitalization.

Economic impact of tolvaptan treatment vs. fluid restriction based on real-world data among hospitalized patients with heart failure and hyponatremia

OBJECTIVES

To estimate the cost difference associated with tolvaptan treatment vs. fluid restriction (FR) among hospitalized patients with heart failure (HF) and hyponatremia (HN) based on a real-world registry of HN patients.

METHODS

An Excel-based economic model was developed to evaluate the cost impact of tolvaptan treatment vs. FR. Model input for hospital length of stay (LOS) was based on published data from the Hyponatremia Registry (HNR). Based on HNR data, tolvaptan-treated patients had a 2-day (median) shorter LOS compared to FR. Real-world effectiveness of tolvaptan treatment from the HNR was applied to a national sample of inpatients visits from the Premier Hospital database to estimate the potential LOS-related cost difference between tolvaptan treatment and FR. A one-way sensitivity and multivariable Monte Carlo sensitivity analysis were conducted.

RESULTS

Economic modeling results of the base-case analysis indicated that among hospitalized patients with HF, the hospital cost per admission, not including HN drug cost, was $3453 lower among patients treated with tolvaptan vs. FR, due to the shorter LOS associated with tolvaptan treatment. At wholesale acquisition cost of $362 per day and an average treatment duration of 3.2 days, the pharmacy cost of tolvaptan treatment per admission was estimated at $1157. Thus, after factoring the decrease in hospital medical costs and increase in pharmacy costs associated with tolvaptan treatment, results indicated a cost-offset opportunity of -$2296 per admission for patients treated with tolvaptan versus FR. Results of the sensitivity analyses were consistent with the base-case analysis.

LIMITATIONS

The model derives inputs from real-world observational data. No causal relationship can be inferred from this analysis.

CONCLUSIONS

Based on this economic analysis, tolvaptan treatment vs. FR among hospitalized patients with HF and HN may be associated with lower hospital-related costs, which offset the increase in pharmacy costs associated with tolvaptan treatment.

Incidence, Severity, and Association With Adverse Outcome of Hyponatremia in Children Hospitalized With Heart Failure

Hyponatremia is a common finding in adults hospitalized with heart failure (HF) and is associated with longer hospital stays and increased mortality. The significance of hyponatremia in children with HF is not known. We sought to determine the incidence of hyponatremia and association with clinical outcome in children hospitalized with HF. Admission and inpatient serum sodium concentrations were analyzed in 141 consecutive children hospitalized with acute decompensated HF. Inclusion criteria include patients (age, birth to 21 years) with biventricular hearts who were hospitalized for HF from January 2007 to December 2012. The primary composite end point was death, cardiac transplantation, or the use of mechanical circulatory support (MCS) during hospitalization. Data for 141 patients were included in the analysis. The cohort included 48 patients (34%) with preexisting HF. Mean serum sodium at admission was 136 ± 4 mmol/L (range 124 to 150 mmol/L). Hyponatremia (serum sodium <135 mmol/L) was present in 45 patients (32%) at admission. Seventy-one patients (75%) with normal serum sodium concentrations at admission subsequently developed acquired hyponatremia during their hospitalization. Hyponatremia persisted at discharge in 17 of 66 patients (26%). Fifty-eight patients (41%) reached the composite end point during hospitalization (death, n = 15; cardiac transplantation, n = 27; MCS, n = 46). Hyponatremia at admission was independently associated with death, cardiac transplantation, or the use of MCS during hospitalization (odds ratio 3.1, p = 0.02). In conclusion, hyponatremia occurs commonly in children hospitalized with acute decompensated HF and is associated with increased risk of in-hospital mortality, cardiac transplantation, and need for MCS.

Acid-base and electrolyte abnormalities in heart failure: pathophysiology and implications

Electrolyte and acid–base abnormalities are a frequent and potentially dangerous complication in subjects with congestive heart failure. This may be due either to the pathophysiological alterations present in the heart failure state leading to neurohumoral activation (stimulation of the renin–angiotensin–aldosterone system, sympathoadrenergic stimulation), or to the adverse events of therapy with diuretics, cardiac glycosides, and ACE inhibitors. Subjects with heart failure may show hyponatremia, magnesium, and potassium deficiencies; the latter two play a pivotal role in the development of cardiac arrhythmias. The early identification of these alterations and the knowledge of the pathophysiological mechanisms are very useful for the management of these patients.

Effectiveness of protocol guided heparin anticoagulation in patients with the TandemHeart percutaneous ventricular assist device

The purpose of this analysis is to assess the effectiveness of heparin anticoagulation in cardiogenic shock patients with TandemHeart percutaneous ventricular assist device support for which the institution's TandemHeart heparin protocol was implemented compared to those managed without protocol. This retrospective analysis included 15 patients in the protocol group and 10 patients in the nonprotocol group. Patients in the protocol group had a higher percentage of therapeutic activated partial thromboplastin time (aPTT) and lower percentage of supra-therapeutic aPTT values compared to the nonprotocol group. We conclude that TandemHeart anticoagulation may be more effectively managed through the use of a protocol than without any protocol.

Prevalence, predictors, and outcomes of cardiorenal syndrome in children with dilated cardiomyopathy: a report from the Pediatric Cardiomyopathy Registry

BACKGROUND

The association of cardiorenal syndrome (CRS) with mortality in children with dilated cardiomyopathy (DCM) is unknown.

METHODS

With a modified Schwartz formula, we estimated glomerular filtration rates (eGFR) for children ≥1 year of age with DCM enrolled in the Pediatric Cardiomyopathy Registry at the time of DCM diagnosis and annually thereafter. CRS was defined as an eGFR of <90 mL/min/1.73 m(2). Children with and without CRS were compared on survival and serum creatinine concentrations (SCr). The association between eGFR and echocardiographic measures was assessed with linear mixed-effects regression models.

RESULTS

Of 285 eligible children with DCM diagnosed at ≥1 year of age, 93 were evaluable. CRS was identified in 57 of these 93 children (61.3%). Mean (standard deviation) eGFR was 62.0 (22.6) mL/min/1.73 m(2) for children with CRS and 108.0 (14.0) for those without (P < 0.001); median SCr concentrations were 0.9 and 0.5 mg/dL, respectively (P < 0.001). The mortality hazard ratio of children with CRS versus those with no CRS was 2.4 (95% confidence interval 0.8-7.4). eGFR was positively correlated with measures of left ventricular function and negatively correlated with age.

CONCLUSIONS

CRS in children newly diagnosed with DCM may be associated with higher 5-year mortality. Children with DCM, especially those with impaired left ventricular function, should be monitored for renal disease.

Predictors of clinical outcomes in acute decompensated heart failure: Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure outcome models

BACKGROUND

Patients hospitalized for acute decompensated heart failure (ADHF) are at high risk for early mortality and rehospitalization. Risk stratification of ADHF using clinically available data on admission is increasingly important to integrate with clinical pathways. Our goal was to create a simple method of screening patients upon admission to identify those with increased risk of future adverse events.

METHODS

Using ASCEND-HF, a pragmatic clinical trial conducted in 398 sites globally, we developed and validated logistic regression risk models for (a) 30-day mortality/HF rehospitalization, (b) 30-day mortality/all-cause rehospitalization, (c) 30-day all-cause mortality, and (d) 180-day all-cause mortality. Fifty-one candidate variables were evaluated based on prior publications and clinical review. Final models were selected based on stepwise selection with entry and a staying criterion of P < .01. The 30-day mortality model was externally validated, and coefficients were converted to an additive risk score.

RESULTS

Among 7,141 patients, the median age was 67 years, 34% were female, and 80% had a left ventricular ejection fraction <40%. The models had between 5 and 12 risk factors with c-indices ranging from 0.68 to 0.75. A simplified score, including age, systolic blood pressure, sodium, blood urea nitrogen, and dyspnea at rest, discriminated 30-day mortality risk from 0.5% (score 0) to 53% (score 10).

CONCLUSIONS

Commonly available clinical variables provide simple risk stratification for clinical outcomes among patients with ADHF, and these models may be considered for integration into routine clinical care.

Moderate hyponatremia is associated with increased risk of mortality: evidence from a meta-analysis

Background

Hyponatremia is the most common electrolyte disorder in clinical practice, and evidence to date indicates that severe hyponatremia is associated with increased morbidity and mortality. The aim of our study was to perform a meta-analysis that included the published studies that compared mortality rates in subjects with or without hyponatremia of any degree.

Methods and Findings

An extensive Medline, Embase and Cochrane search was performed to retrieve the studies published up to October 1^st 2012, using the following words: “hyponatremia” and “mortality”. Eighty-one studies satisfied inclusion criteria encompassing a total of 850222 patients, of whom 17.4% were hyponatremic. The identification of relevant abstracts, the selection of studies and the subsequent data extraction were performed independently by two of the authors, and conflicts resolved by a third investigator. Across all 81 studies, hyponatremia was significantly associated with an increased risk of overall mortality (RR = 2.60[2.31–2.93]). Hyponatremia was also associated with an increased risk of mortality in patients with myocardial infarction (RR = 2.83[2.23–3.58]), heart failure (RR = 2.47[2.09–2.92]), cirrhosis (RR = 3.34[1.91–5.83]), pulmonary infections (RR = 2.49[1.44–4.30]), mixed diseases (RR = 2.59[1.97–3.40]), and in hospitalized patients (RR = 2.48[2.09–2.95]). A mean difference of serum [Na⁺] of 4.8 mmol/L was found in subjects who died compared to survivors (130.1±5.6 vs 134.9±5.1 mmol/L). A meta-regression analysis showed that the hyponatremia-related risk of overall mortality was inversely correlated with serum [Na⁺]. This association was confirmed in a multiple regression model after adjusting for age, gender, and diabetes mellitus as an associated morbidity.

Conclusions

This meta-analysis shows for the first time that even a moderate serum [Na⁺] decrease is associated with an increased risk of mortality in commonly observed clinical conditions across large numbers of patients.

Hyponatremia in patients with heart failure

The present review analyses the mechanisms relating heart failure and hyponatremia, describes the association of hyponatremia with the progress of disease and morbidity/mortality in heart failure patients and presents treatment options focusing on the role of arginine vasopressin (AVP)-receptor antagonists. Hyponatremia is the most common electrolyte disorder in the clinical setting and in hospitalized patients. Patients with hyponatremia may have neurologic symptoms since low sodium concentration produces brain edema, but the rapid correction of hyponatremia is also associated with major neurologic complications. Patients with heart failure often develop hyponatremia owing to the activation of many neurohormonal systems leading to decrease of sodium levels. A large number of clinical studies have associated hyponatremia with increased morbidity and mortality in patients hospitalized for heart failure or outpatients with chronic heart failure. Treatment options for hyponatremia in heart failure, such as water restriction or the use of hypertonic saline with loop diuretics, have limited efficacy. AVP-receptor antagonists increase sodium levels effectively and their use seems promising in patients with hyponatremia. However, the effects of AVP-receptor antagonists on hard outcomes in patients with heart failure and hyponatremia have not been thoroughly examined.

Impact of social factors on risk of readmission or mortality in pneumonia and heart failure: systematic review

BACKGROUND

Readmission and mortality after hospitalization for community-acquired pneumonia (CAP) and heart failure (HF) are publically reported. This systematic review assessed the impact of social factors on risk of readmission or mortality after hospitalization for CAP and HF-variables outside a hospital's control.

METHODS

We searched OVID, PubMed and PSYCHINFO for studies from 1980 to 2012. Eligible articles examined the association between social factors and readmission or mortality in patients hospitalized with CAP or HF. We abstracted data on study characteristics, domains of social factors examined, and presence and magnitude of associations.

RESULTS

Seventy-two articles met inclusion criteria (20 CAP, 52 HF). Most CAP studies evaluated age, gender, and race and found older age and non-White race were associated with worse outcomes. The results for gender were mixed. Few studies assessed higher level social factors, but those examined were often, but inconsistently, significantly associated with readmissions after CAP, including lower education, low income, and unemployment, and with mortality after CAP, including low income. For HF, older age was associated with worse outcomes and results for gender were mixed. Non-Whites had more readmissions after HF but decreased mortality. Again, higher level social factors were less frequently studied, but those examined were often, but inconsistently, significantly associated with readmissions, including low socioeconomic status (Medicaid insurance, low income), living situation (home stability rural address), lack of social support, being unmarried and risk behaviors (smoking, cocaine use and medical/visit non-adherence). Similar findings were observed for factors associated with mortality after HF, along with psychiatric comorbidities, lack of home resources and greater distance to hospital.

CONCLUSIONS

A broad range of social factors affect the risk of post-discharge readmission and mortality in CAP and HF. Future research on adverse events after discharge should study social determinants of health.

Hyponatremia and mortality: moving beyond associations

Acute hyponatremia can cause death if cerebral edema is not treated promptly. Conversely, if chronic hyponatremia is corrected too rapidly, osmotic demyelination may ensue, which also potentially is lethal. However, these severe complications of hyponatremia are relatively uncommon and often preventable. More commonly, hyponatremia predicts mortality in patients with advanced heart failure or liver cirrhosis. In these conditions, it generally is assumed that hyponatremia reflects the severity of the underlying disease rather than contributing directly to mortality. The same assumption holds for the recently reported associations between hyponatremia and mortality in patients with pulmonary embolism, pulmonary hypertension, pneumonia, and myocardial infarction. However, recent data suggest that chronic and mild hyponatremia in the general population also are associated with mortality. In addition, hyponatremia has been associated with mortality in long-term hemodialysis patients without residual function in whom the underlying disease cannot be responsible for hyponatremia. These new data raise the question of whether hyponatremia by itself can contribute to mortality or it remains a surrogate marker for other unknown risk factors. We review hyponatremia and mortality and explore the possibility that hyponatremia perturbs normal physiology in the absence of cerebral edema or osmotic demyelination.

Healthcare resource burden associated with hyponatremia among patients hospitalized for heart failure in the US

OBJECTIVE

To evaluate the burden of hyponatremia in terms of hospital resource utilization, costs, and 30-day hospital readmission among patients hospitalized for heart failure (HF) in routine clinical practice.

METHODS

Hyponatremic (HN) patients (≥18 years of age) with HF discharged between January 2, 2007 and March 31, 2010 were selected from the Premier Hospital Database and matched to non-HN HF patients using exact and propensity score matching. Univariate and multivariate statistics were utilized to compare hospital resource utilization (total and intensive care unit (ICU)) and associated costs and 30-day hospital readmission among cohorts.

RESULTS

The study population included 51,710 subjects (HN = 25,855, non-HN = 25,855). In comparison to the non-HN cohort, length of stay (LOS) (7.7 ± 8.3 vs 6.3 ± 7.6 days, p < 0.001), hospitalization cost ($13,339 ± $19,273 vs $10,475 ± 15,157, p < 0.001), ICU LOS (4.9 ± 5.4 vs 4.2 ± 5.4 days, p < 0.001) and ICU cost ($7195 ± $9522 vs $5618 ± 10,919, p < 0.001) as well as rate of 30-day readmission (all cause: 25.3% vs 22.2%, p < 0.001; hyponatremia-related: 21.4% vs 5.0%, p < 0.001) were greater for the HN cohort. After adjustment, hyponatremia was associated with a 21.5% increase in hospital LOS, a 25.6% increase in hospital cost, a 13.7% increase in ICU LOS and a 24.6% increase in ICU cost. Additionally, hyponatremia was associated with increased risk of ICU admission (Odds Ratio (OR) = 1.58, [CI = 1.37, 1.84], p < 0.001) and 30-day hospital readmission (all cause: OR = 1.19, [CI = 1.14, 1.24], p < 0.001; hyponatremia-related: 5.10 [CI = 4.77, 5.46], p < 0.001).

LIMITATIONS

Laboratory data for serum sodium level are not available in the Premier database and the severity of hyponatremia could not be established, although several patient variables were controlled for in this study by exact and propensity score matching techniques.

CONCLUSIONS

Hyponatremia in HF patients is a predictor of increased hospital resource use and represents a potential target for intervention to reduce healthcare expenditures.

Clinical challenge of hyponatremia in heart failure

Hyponatremia is a significant and independent predictor of outcomes including rehospitalization and mortality in patients with both acute decompensated heart failure (HF) and chronic HF. Even modest degrees of hyponatremia are associated with a poorer prognosis. Treatment options include fluid restriction and the vaptan class ("aquaretics") in select patients.

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.

Mild hyponatremia carries a poor prognosis in community subjects

OBJECTIVE

Hyponatremia has been shown to predict adverse outcome in congestive heart failure and pneumonia among other common clinical entities, but its significance in the general population is elusive.

METHODS

The population-based Copenhagen Holter Study included 671 men and women aged 55 to 75 years with no history of cardiovascular disease, stroke, or cancer. Baseline evaluation included 48-hour ambulatory electrocardiogram monitoring, blood tests, and a questionnaire. Hyponatremia was defined as s-Na < or = 134 mEq/L or s-Na < or = 137 mEq/L according to previously accepted definitions. An adverse outcome was defined as deaths or myocardial infarction. Median follow-up was 6.3 years.

RESULTS

Fourteen subjects (2.1%, group A) had s-Na < or = 134 mEq/L, and 62 subjects (9.2%, group B) had s-Na < or = 137 mEq/L. No subject had s-Na < 129 mEq/L. An adverse outcome occurred in 43% of group A, 27% of group B, and 14% of subjects with s-Na >137 mEq/L (controls) (P < .002). Adjusted hazard ratio for adverse outcome was 3.56 (95% confidence interval [CI], 1.53-8.28, P < .005) in group A compared with controls and 2.21 (95% CI, 1.29-3.80, P < .005) in group B after controlling for age, gender, smoking, diabetes, low-density lipoprotein cholesterol, and blood pressure. The hazard ratios were robust for additional adjusting for variables showing univariate association to hyponatremia (ie, beta-blocker and diuretic use, heart rate variability, creatinine, C-reactive protein, and NT-pro brain natriuretic peptide). By excluding diuretic users (18% of subjects), the adjusted hazard ratio for adverse outcome was 8.00 (95% CI, 3.04-21.0, P < .0001) in group A and 3.17 (95% CI, 1.76-5.72, P = .0001) in group B compared with controls.

CONCLUSION

Hyponatremia is an independent predictor of deaths and myocardial infarction in middle-aged and elderly community subjects.

Diagnosis and management of hyponatremia in acute illness

PURPOSE OF REVIEW

Hyponatremia is the most common electrolyte disorder present in hospitalized patients. Acute and severe hyponatremia can cause significant morbidity and mortality. The present review discusses the epidemiology, causes, and a practical approach to the diagnosis and management of acute and chronic hyponatremia, including the appropriate use of hypertonic saline and potential future use of the new V2 vasopressin receptor antagonists in critically ill patients.

RECENT FINDINGS

The increasing knowledge of aquaporin water channels and the role of vasopressin in water homeostasis have enhanced our understanding of hyponatremic disorders. Increased vasopressin secretion due to nonosmotic stimuli leads to decreased electrolyte-free water excretion with resulting water retention and hyponatremia. Vasopressin receptor antagonists induce electrolyte-free water diuresis without natriuresis and kaliuresis. Phase three trials indicate that these agents predictably reduce urine osmolality, increase electrolyte-free water excretion, and raise serum sodium concentration. They are likely to become a mainstay of treatment of euvolemic and hypervolemic hyponatremia.

SUMMARY

The correct diagnosis and management of hyponatremia is complex and requires a systematic approach. Vasopressin receptor antagonists are potential tools in the management of hyponatremia. Further studies are needed to determine their role in the treatment of acute, severe, life-threatening hyponatremia as well as chronic hyponatremia.

Hyponatraemia in patients with normal pressure hydrocephalus

BACKGROUND

In clinical practice, hyponatraemia was frequently found in patients with hydrocephalus. We conducted this study to determine the prevalence and risk factors for hyponatraemia in patients with normal pressure hydrocephalus (NPH).

METHODS

We retrospectively reviewed all patients with NPH who were admitted to China Medical University Hospital between 1998 and 2006. Hyponatraemia was defined as a plasma sodium concentration < 135 mEq/l on admission. Possible risk factors between patients with and without hyponatraemia were analysed using Student's t-test or chi2 test. The association between hyponatraemia and possible factors was analysed using multivariate logistic regression. The odds ratio was calculated to determine the effect of possible risk factors.

RESULTS

A total of 146 patients (84 men and 62 women) who had NPH with a mean age of 66.1 +/- 15.9 years old were reviewed and 33 (22.6%) patients were found having hyponatraemia. Patients who developed hyponatraemia had a significantly higher prevalence of hypertension, use of nasogastric tube (NG), bed-ridden status and fever. In multivariate logistic regression, the presence of hypertension and the use of NG were two important risk factors for hyponatraemia. The odds ratio (95% CI) for hypertension and NG were 2.604 (95% CI: 1.136-5.967, p = 0.024) and 7.179 (95% CI: 2.3-22.409, p = 0.001) respectively.

CONCLUSION

Hyponatraemia is not uncommon in patients with NPH. Physicians should be aware of this complication and obtain necessary laboratory examination for early detection of hyponatraemia.

Delayed enhancement cardiovascular magnetic resonance as a novel technique to predict cardiac events in dilated cardiomyopathy patients

PURPOSE

Delayed enhancement cardiovascular magnetic resonance (DE-CMR) can detect cardiac scarring and has the potential to visualize the progression of myocardial remodeling. We determined whether DE-CMR can predict cardiac events in dilated cardiomyopathy patients.

MATERIALS AND METHODS

Transthoracic echocardiography, coronary arteriography, and DE-CMR studies were performed in 60 consecutive dilated cardiomyopathy (DCM) patients. Percent delayed enhancement (%DE) was determined as the ratio of the area showing delayed enhancement to the total myocardial area in three short-axis views. Patients were classified as advanced group (Group A) when %DE was 10% or higher, and as non-advanced group (Group NA) when %DE was less than 10%. The incidence of cardiac events and the clinical history were compared between Group A and Group NA.

RESULTS

There were 11 patients in Group A and 49 patients in Group NA. The incidence of cardiac events was significantly higher in Group A (36%; 4/11 patients) than in Group NA (2.0%; 1/49 patients) (log rank, p=0.0001).

CONCLUSION

DE-CMR is a useful tool to predict cardiac events in DCM patients.

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.

Risk stratification in women enrolled in the Acute Decompensated Heart Failure National Registry Emergency Module (ADHERE-EM)

OBJECTIVES

It has been reported that the mortality risk for heart failure differs between men and women. It has been postulated that this is due to differences in comorbid features. Variation in risk profiles by gender may limit the performance of stratification algorithms available for heart failure in women. This analysis examined the ability of a published risk stratification model to predict outcomes in women.

METHODS

The Acute Decompensated Heart Failure National Registry Emergency Module (ADHERE-EM) database was used. Characteristics, treatments, and outcomes for men and women were compared. The ADHERE registry classification and regression tree (CART) analysis was used for the risk stratification evaluation.

RESULTS

Of 10,984 ADHERE-EM patients, 5,736 (52.2%) were women. In-hospital mortality was similar between men and women (p = 0.727). Significant differences (p < 0.0002) were noted by gender in all three variables in the CART model (blood urea nitrogen [BUN] > or = 43 mg/dL, systolic blood pressure < 115 mm Hg, and serum creatinine > or = 2.75 mg/dL). However, the CART model effectively stratified both genders into distinct risk groups with no significant difference in mortality by gender within stratified groups.

CONCLUSIONS

The ADHERE Registry CART tool is effective at predicting risk in ED patients, regardless of gender.

Recognition and treatment of hyponatremia in acutely ill hospitalized patients

OBJECTIVE

The objective of this paper was to discuss the diagnosis, pathophysiology, and management of hyponatremia among critically ill, hospitalized patients (eg, after surgery or in the intensive care unit).

METHODS

English-language literature published between 1967 and 2006 was searched using several key words (AVP receptor antagonists, hyponatremia, SIADH, conivaptan, tolvaptan, and lixivaptan) and by accessing MEDLINE and ScienceDirect. Meeting abstracts from scientific sessions (American Society of Nephrology Renal Week 2004 and the Endocrine Society's 87th Annual Meeting [2005]) were reviewed. The package insert for conivaptan hydrochloride injection was referenced from . Clinical trials included in this review were randomized and placebo controlled.

RESULTS

Based on the literature we researched, hyponatremia is the most common electrolyte disorder encountered in critical care and is associated with a variety of conditions, including congestive heart failure and the syndrome of inappropriate antidiuretic hormone secretion. Because hyponatremia can arise in hypervolemic, euvolemic, and hypovolemic states, clinicians may not recognize its presence and cause. Incorrect management can lead to significant morbidity and mortality. Physicians need to recognize risk factors and symptoms and use appropriate treatment guidelines for hyponatremia. Traditionally, therapy for hyponatremia has been limited by efficacy and safety concerns. Arginine vasopressin (AVP) receptor antagonists, therapeutic agents that promote aquaresis in patients with hyponatremia by targeting V(1a) receptors in the vascular smooth muscle, V(2) receptors in the kidney, or both, are under development. A dual-receptor antagonist targeting both V(1a) and V(2) receptors is now approved for the treatment of euvolemic hyponatremia in hospitalized patients.

CONCLUSIONS

Hyponatremia, an electrolyte abnormality found in critically ill patients, can be associated with significant morbidity and mortality. AVP receptor antagonists show promise as effective and tolerable treatments for patients with hyponatremia.

Hyponatremia, arginine vasopressin dysregulation, and vasopressin receptor antagonism

Hyponatremia is often associated with arginine vasopressin (AVP) dysregulation that is regulated by the hypothalamo-neurohypophyseal tract in response to changes in plasma osmolality, commonly in patients with the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Potentially lethal complications of hyponatremia most frequently involve the central nervous system and include anorexia, fatigue, lethargy, delirium, seizures, hypothermia and coma, and require prompt treatment. Chronic hyponatremia also complicates patient care and is associated with increased morbidity and mortality, particularly among patients with congestive heart failure. Conventional treatments for hyponatremia (e.g. fluid restriction, diuretic treatment, and sodium replacement) may not be effective in all patients and can lead to significant adverse events. Preclinical and clinical trial results have shown that AVP receptor antagonism is a promising approach to the treatment of hyponatremia that directly addresses the effects of increased AVP and consequent decreased aquaresis, the electrolyte-sparing excretion of free water. Agents that antagonize V(2) receptors promote aquaresis and can lead to increased serum sodium. Dual-receptor antagonism, in which both V(2) and V(1A) receptors are blocked, may provide additional benefits in patients with hyponatremia.

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.

Hyponatremia in congestive heart failure

Hyponatremia has been identified as a risk factor for increased morbidity and mortality in patients with congestive heart failure (CHF) and other edematous disorders and can lead to severe neurologic derangements. Low cardiac output and blood pressure associated with CHF triggers a compensatory response by the body that activates several neurohormonal systems designed to preserve arterial blood volume and pressure. Hyponatremia in patients with CHF is primarily caused by increased activity of arginine vasopressin (AVP). AVP increases free-water reabsorption in the renal collecting ducts, increasing blood volume and diluting plasma sodium concentrations. Hyponatremia may also be triggered by diuretic therapy used in the management of symptoms of CHF. Hyponatremic disorders occur when the normal ratio of solutes to body water content is altered by parallel changes in serum sodium and osmolality. Hyponatremia is generally defined as a serum sodium ion concentration <135 to 136 mmol/L and can be broadly categorized into 2 types, dilutional or depletional. Dilutional hyponatremia is the most common form of hyponatremia and is caused by excess water retention. Depletional hyponatremia is usually hypovolemic, with an absolute deficiency of water but a relative excess of body water compared with sodium concentration.