Additive diagnostic and prognostic value of bioelectrical impedance vector analysis (BIVA) to brain natriuretic peptide 'grey-zone' in patients with acute heart failure in the emergency department

[Prognostic value of electrical bioimpedance measured with a portable and wireless device in acute heart failure]

INTRODUCTION AND OBJECTIVES

The current evaluation of acute heart failure (HF) does not allow an adequate prediction of its evolution. The electrical bioimpedance (BI) allows knowing the state of blood volume, until now only with fixed equipment. We have developed and validated a portable and wireless device to measure BI at the ankle (IVOL). The objective of the study is to know the long-term prognostic value of the point measurement of BI with IVOL in patients with acute HF.

METHODS

A prospective cohort study of unselected patients admitted for acute HF in a tertiary hospital. The association between BI and different clinical, analytical and echocardiographic variables on admission and clinical evolution were analyzed.

RESULTS

76 patients were included (mean age 66.1 years, 71.1% men, 68.4% hypertensive, 34.2% diabetic, mean NT-ProBNP: 7,103 pg / ml). Of these, 52.6% with non-preserved left ventricular ejection fraction (LVEF) (<50%) and 56.6% with right ventricular (RV) dysfunction. 26.3% died during a mean follow-up of 35.8 months. Survival in patients with BI≤21,8Ω was lower, globally and in the subgroups of patients without preserved LVEF and with RV dysfunction, P<.008). In the multivariate analysis, a BI≥21.8Ω was an independent survival factor (HR: 0.242; 95% CI: 0.86-0.681; P=.007).

CONCLUSIONS

BI values measured with IVOL may be an independent predictor of long-term mortality in patients hospitalized for acute HF. This prognostic value is maintained in patients without preserved LVEF function and with RV dysfunction.

Proposal and validation of an equation to identify sarcopenia using bioelectrical impedance analysis-derived parameters

OBJECTIVE

This study aimed to develop a simpler approach for diagnosing sarcopenia by using only bioelectrical impedance vector analysis parameters.

METHODS

The study design was a cross-sectional study. The research was conducted based on the Itabashi Longitudinal Study on Aging, a community-based cohort study, with data collected from the 2022 and 2023 surveys in Itabashi Ward, Tokyo, Japan. The development cohort consisted of 1146 participants from the 2022 survey, and the validation cohort included 656 participants from the 2023 survey. Both cohorts were comprised of community-dwelling older adults with similar inclusion criteria. Sarcopenia was defined according to the Asian Working Group for Sarcopenia 2019 criteria. The logistic model utilized height divided by impedance at 50 kHz and phase angle to establish a new regression equation to identify sarcopenia. Regression equations were generated for the development cohort and validated for the validation cohort. Discriminatory ability was assessed using the area under the receiver operating characteristic curve (AUC) for men and women.

RESULTS

The prevalence of sarcopenia was 20.7% and 14.8% in the development and validation cohort, respectively. The AUC (95% confidence interval) of the logistic model in discriminating sarcopenia was 0.92 (0.88, 0.95) for men and 0.82 (0.78, 0.86) for women in the development cohort and 0.85 (0.78, 0.91) for men and 0.90 (0.86, 0.95) for women in the validation cohort.

CONCLUSION

The study demonstrated that a simple formula using bioelectrical parameters at 50 kHz proved useful in identifying sarcopenia in the older adult population.

The Importance of Optimal Hydration in Patients with Heart Failure-Not Always Too Much Fluid

Heart failure (HF) is a leading cause of morbidity and mortality and a major public health problem. Both overhydration and dehydration are non-physiological states of the body that can adversely affect human health. Congestion and residual congestion are common in patients hospitalized for HF and are associated with poor prognosis and high rates of rehospitalization. However, the clinical problem of dehydration is also prevalent in healthcare and community settings and is associated with increased morbidity and mortality. This article provides a comprehensive review of the issue of congestion and dehydration in HF, including HF guidelines, possible causes of dehydration in HF, confirmed and potential new diagnostic methods. In particular, a full database search on the relationship between dehydration and HF was performed and all available evidence in the literature was reviewed. The novel hypothesis of chronic subclinical hypohydration as a modifiable risk factor for HF is also discussed. It is concluded that maintaining euvolemia is the cornerstone of HF management. Physicians have to find a balance between decongestion therapy and the risk of dehydration.

The role of bioimpedance analysis in overweight and obese patients with acute heart failure: a pilot study

AIMS

Residual congestion at the time of hospital discharge is an important readmission risk factor, and its detection with physical examination and usual diagnostic techniques have strong limitations in overweight and obese patients. New tools like bioelectrical impedance analysis (BIA) could help to determine when euvolaemia is reached. The aim of this study was to investigate the usefulness of BIA in management of heart failure (HF) in overweight and obese patients.

METHODS AND RESULTS

Our study is a single-centre, single-blind, randomized controlled trial that included 48 overweight and obese patients admitted for acute HF. The study population was randomized into two arms: BIA-guided group and standard care. Serum electrolytes, kidney function, and natriuretic peptides were followed up during their hospital stay and at 90 days after discharge. The primary endpoint was development of severe acute kidney injury (AKI) defined as an increase in serum creatinine by >0.5 mg/dL during hospitalization, and the main secondary endpoint was the reduction of N-terminal pro-brain natriuretic peptide (NT-proBNP) levels during hospitalization and within 90 days after discharge. The BIA-guided group showed a remarkable lower incidence of severe AKI, although no significant differences were found (41.4% vs. 16.7%; P = 0.057). The proportion of patients who achieved levels of NT-proBNP < 1000 pg/mL at 90 days was significantly higher in the BIA-guided group than in the standard group (58.8% vs. 25%; P = 0.049). No differences were observed in the incidence of adverse outcomes at 90 days.

CONCLUSIONS

Among overweight and obese patients with HF, BIA reduces NT-proBNP levels at 90 days compared with standard care. In addition, there is a trend towards lower incidence of AKI in the BIA-guided group. Although more studies are required, BIA could be a useful tool in decompensated HF management in overweight and obese patients.

A Current Review of the Uses of Bioelectrical Impedance Analysis and Bioelectrical Impedance Vector Analysis in Acute and Chronic Heart Failure Patients: An Under-valued Resource?

BACKGROUND

There is a need to detect and prevent fluid overload and malnutrition in heart failure. Bioelectrical impedance analysis and bioelectrical impedance vector analysis are medical instruments that can advance heart failure management by generating values of body composition and body water, assisting clinicians to detect fluid and nutritional status. However, there is a lack of evidence to summarise how they have been used among heart failure patients.

METHOD

A systematic search was conducted.

RESULT

Two hundred and four papers were screened. Forty-eight papers were reviewed, and 46 papers were included in this review. The literature shows that bioelectrical impedance analysis and bioelectrical impedance vector analysis were mostly used to assess fluid and nutritional status, together with diagnostic and prognostic values. Contraindication of using BIA and implications for practice are also demonstrated.

CONCLUSION

The findings suggest that bioelectrical impedance vector analysis is superior to bioelectrical impedance analysis when assessing hydration/nutritional status in heart failure. Assessing a patient using bioelectrical impedance analysis /bioelectrical impedance vector analysis, together with natriuretic peptide -heart failure biomarkers, increases the diagnostic accuracy of heart failure. Further studies are required to examine the cost effectiveness of using these instruments in clinical practice.

Prognostic value of phase angle and bioelectrical impedance vector in critically ill patients: A systematic review and meta-analysis of observational studies

BACKGROUND AND AIMS

Assessment of the raw parameters derived from bioelectrical impedance analysis (BIA) has gained emphasis in critically ill patients. The phase angle (PhA) reflects the integrity of the cell membrane, and bioelectrical impedance vector analysis (BIVA) is indicative of patients' hydration status. The aim of this study was to investigate whether these parameters are associated with clinical outcomes in the intensive care unit (ICU) setting.

METHODS

We conducted a systematic review with meta-analysis. We searched PubMed, Embase, Scopus and Web of Science for all published observational studies without language restrictions up to April 2022. Two reviewers independently performed study selection and data extraction. We judged the risk of bias by the Newcastle-Ottawa Scale and the certainty of evidence by the GRADE approach. Mortality was the primary outcome. Secondary outcomes included ICU length of stay, hospital length of stay, duration of mechanical ventilation, nutritional risk, and malnutrition. A meta-analysis with a random-effect model was performed to combine data on R version 3.6.2.

RESULTS

Twenty-seven studies were included in the systematic review (4872 participants). Pooled analysis revealed that patients with low PhA had a higher risk of death (14 studies; RR = 1.82, 95% CI 1.46 to 2.26; I² = 42%) and spent more days in ICU (6 studies; MD = 1.79, 95% CI 0.33 to 3.24, I² = 69%) in comparison to patients with normal PhA. The pooled analysis also showed higher PhA values in survivors compared to non-survivor patients (12 studies; MD = 0.75°, 95% CI 0.60° to 0.91°, I² = 31%). Overhydration defined by BIVA was not a predictor of mortality (4 studies; RR = 1.01, 95% CI 0.70 to 1.46; I² = 0%). More than 40% of primary studies were classified with a high risk of bias, and the quality of evidence ranged from low to very low.

CONCLUSIONS

This meta-analysis revealed, with limited evidence, that low PhA was associated with higher mortality and ICU length of stay, while overhydration identified by BIVA was not a predictor of death in critically ill patients.

Bioimpedance Indices of Fluid Overload and Cardiorenal Outcomes in Heart Failure and Chronic Kidney Disease: a Systematic Review

BACKGROUND

Bioimpedance-based estimates of fluid overload have been widely studied and systematically reviewed in populations of those undergoing dialysis, but data from populations with heart failure or nondialysis chronic kidney disease (CKD) have not.

METHODS AND RESULTS

We conducted a systematic review of studies using whole-body bioimpedance from populations with heart failure and nondialysis CKD that reported associations with mortality, cardiovascular outcomes and/or CKD progression. We searched MEDLINE, Embase databases and the Cochrane CENTRAL registry from inception to March 14, 2022. We identified 31 eligible studies: 20 heart failure and 11 CKD cohorts, with 2 studies including over 1000 participants. A wide range of various bioimpedance methods were used across the studies (heart failure: 8 parameters; CKD: 6). Studies generally reported positive associations, but between-study differences in bioimpedance methods, fluid overload exposure definitions and modeling approaches precluded meta-analysis. The largest identified study was in nondialysis CKD (Chronic Renal Insufficiency Cohort, 3751 participants), which reported adjusted hazard ratios (95% confidence intervals) for phase angle < 5.59 vs ≥ 6.4 of 2.02 (1.67-2.43) for all-cause mortality; 1.80 (1.46-2.23) for heart failure events; and 1.78 (1.56-2.04) for CKD progression.

CONCLUSIONS

Bioimpedance indices of fluid overload are associated with risk of important cardiorenal outcomes in heart failure and CKD. Facilitation of more widespread use of bioimpedance requires consensus on the optimum device, standardized analytical methods and larger studies, including more detailed characterization of cardiac and renal phenotypes.

Bioimpedance Vector Analysis for Heart Failure: Should We Put It on the Agenda?

Heart failure is a clinical syndrome, resulting in increased intracardiac pressure and/or decreased cardiac output under rest or stress. In acute decompensated heart failure, volume assessment is essential for clinical diagnosis and management. More and more evidence shows the advantages of bioimpedance vector analysis in this issue. Here, we critically present a brief review of bioimpedance vector analysis in the prediction and management of heart failure to give a reference to clinical physicians and guideline makers.

Assessment of Fluid Status by Bioimpedance Analysis and Central Venous Pressure Measurement and Their Association with the Outcomes of Severe Acute Kidney Injury

Background and Objectives: Fluid disbalance is associated with adverse outcomes in critically ill patients with acute kidney injury (AKI). In this study, we intended to assess fluid status using bioimpedance analysis (BIA) and central venous pressure (CVP) measurement and to evaluate the association between hyperhydration and hypervolemia with the outcomes of severe AKI. Materials and Methods: A prospective study was conducted in the Hospital of the Lithuanian University of Health Sciences Kauno Klinikos. Forty-seven patients treated at the Intensive Care Unit (ICU) with severe AKI and a need for renal replacement therapy (RRT) were examined. The hydration level was evaluated according to the ratio of extracellular water to total body water (ECW/TBW) of bioimpedance analysis and volemia was measured according to CVP. All of the patients were tested before the first hemodialysis (HD) procedure. Hyperhydration was defined as ECW/TBW > 0.39 and hypervolemia as CVP > 12 cm H₂O. Results: According to bioimpedance analysis, 72.3% (n = 34) of patients were hyperhydrated. According to CVP, only 51.1% (n = 24) of the patients were hypervolemic. Interestingly, 69.6% of hypovolemic/normovolemic patients were also hyperhydrated. Of all study patients, 57.4% (n = 27) died, in 29.8% (n = 14) the kidney function improved, and in 12.8% (n = 6) the demand for RRT remained after in-patient treatment. A tendency of higher mortality in hyperhydrated patients was observed, but no association between hypervolemia and outcomes of severe AKI was established. Conclusions: Three-fourths of the patients with severe AKI were hyperhydrated based on bioimpedance analysis. However, according to CVP, only half of these patients were hypervolemic. A tendency of higher mortality in hyperhydrated patients was observed.

Bioimpedance vector analysis in stable chronic heart failure patients: Level of agreement between single and multiple frequency devices

BACKGROUND & AIMS

The accuracy of estimating body composition compartments is critical in the clinical setting. Currently, there are different bioelectrical impedance analysis (BIA) devices available for obtaining raw BIA parameters. The aim of this study was to determine the level of agreement between multiple frequency (MF)-BIA and single frequency (SF)-BIA devices in obtaining raw BIA measurements (resistance (R), reactance (Xc), and phase angle (PhA)), as well as the agreement on the classification of hydration status and body cell mass by the bioelectrical impedance vector analysis (BIVA) method.

METHODS

This cross-sectional study included 406 outpatients with stable chronic heart failure (HF). The raw BIA measurements at 50 kHz obtained by tetrapolar MF-BIA (Bodystat QuadScan 4000) were compared with those obtained by tetrapolar SF-BIA (RJL Quantum X). In addition, the patients were classified by their hydration status and body cell mass according to the BIVA method.

RESULTS

Strong and significant correlations were observed between the two methods in all raw BIA variables (r ≥ 0.90). Lin's concordance correlation coefficient (CCC) values were almost perfect for R (CCC = 0.99; 95% CI 0.997 to 0.998), moderate for Xc (CCC = 0.93; 95% CI 0.92 to 0.94), and poor for PhA (CCC = 0.88; 95% CI 0.85 to 0.90). The agreement obtained in the two classifications (quadrants and hydration status) was >0.81.

CONCLUSIONS

MF-BIA and SF-BIA demonstrated good agreement for measurement of the R parameter; however, the Xc and PhA parameters must be used carefully due to the previously reported variability. Likewise, the agreement in all classifications by the BIVA method was almost perfect.

Cardiovascular health of nonagenarians in southern Italy: a cross-sectional, home-based pilot study of longevity

BACKGROUND

The Cilento region of southern Italy has a high prevalence of nonagenarians and centenarians. Few studies of the oldest old have included echocardiographic and/or electrocardiographic data, in a home-based setting.

OBJECTIVES

The objective of this pilot study was to delineate the key lifestyle, medical, echocardiographic, and electrocardiographic features of a sample of nonagenarians and centenarians and their younger cohabitants from Cilento, via a comprehensive, home-based cardiovascular assessment. The ultimate aim is to identify the cardiovascular profile and lifestyle factors associated with longevity.

METHODS

Twenty-six nonagenarians and centenarians (mean age 94 ± 3 years) and 48 younger cohabitants aged 50-75 years (mean 62 ± 5) underwent a comprehensive cardiovascular evaluation in their homes.

RESULTS

In contrast to their younger cohabitants, nonagenarians and centenarians did not smoke, had lower fasting glucose levels, and lower LDL cholesterol despite being half as likely to be taking statins, and showing similar adherence to a Mediterranean diet. Over half of nonagenarians and centenarians (15/26) remained autonomous with their activities of daily living. Prevalence of self-reported coronary artery disease and stroke among nonagenarians and centenarians was low (11.5%), though a significant number had atrial fibrillation (31%) or congestive heart failure (27%). Although 62% of nonagenarians and centenarians had at least moderate valvular disease on echocardiography, less than 25% of those affected reported dyspnea.

CONCLUSION

Nonagenarians and centenarians in the Cilento region had a healthy metabolic profile and a low prevalence of clinical cardiovascular disease. Even among nonagenarians and centenarians with structural heart abnormalities, report of symptoms is low. Larger studies in the Cilento population may help elucidate the mechanisms underlying cardiovascular health in the oldest old.

Should we overcome the resistance to bioelectrical impedance in heart failure?

INTRODUCTION

Heart failure is associated with increased neurohormonal activation that results in changes in body composition including volume overload and the loss of skeletal muscle, body fat, and bone density. Bioelectrical impedance measures body composition based on the conduction of electrical current through body fluids.

AREAS COVERED

The PubMed and Scopus databases were reviewed up to the third week of June 2020. Cross-sectional studies, retrospective observational studies, prospective observational studies, and randomized controlled trials have examined numerous bioelectrical impedance monitoring strategies to guide the diagnosis, prognosis, and treatment of heart failure. These monitoring strategies include intrathoracic impedance, lung impedance, bioelectrical impedance vector analysis, leg bioelectrical impedance, and thoracic bioreactance.

EXPERT COMMENTARY

Based on the current evidence, more studies are needed to validate bioelectrical impedance in heart failure. Lung impedance appears to be useful for guiding heart failure treatment in patients with ST-elevation myocardial infarction and improving outcomes in outpatients with heart failure. Furthermore, bioelectrical impedance has potential as a noninvasive, quantitative heart failure variable for population-based research.

Cardiorenal Syndrome: Classification, Pathophysiology, Diagnosis, and Treatment Strategies: A Scientific Statement From the American Heart Association

Cardiorenal syndrome encompasses a spectrum of disorders involving both the heart and kidneys in which acute or chronic dysfunction in 1 organ may induce acute or chronic dysfunction in the other organ. It represents the confluence of heart-kidney interactions across several interfaces. These include the hemodynamic cross-talk between the failing heart and the response of the kidneys and vice versa, as well as alterations in neurohormonal markers and inflammatory molecular signatures characteristic of its clinical phenotypes. The mission of this scientific statement is to describe the epidemiology and pathogenesis of cardiorenal syndrome in the context of the continuously evolving nature of its clinicopathological description over the past decade. It also describes diagnostic and therapeutic strategies applicable to cardiorenal syndrome, summarizes cardiac-kidney interactions in special populations such as patients with diabetes mellitus and kidney transplant recipients, and emphasizes the role of palliative care in patients with cardiorenal syndrome. Finally, it outlines the need for a cardiorenal education track that will guide future cardiorenal trials and integrate the clinical and research needs of this important field in the future.

Bioimpedance-Guided Hydration for the Prevention of Contrast-Induced Kidney Injury: The HYDRA Study

BACKGROUND

Intravascular volume expansion plays a major role in the prevention of contrast-induced acute kidney injury (CI-AKI). Recommended standard amounts of fluid infusion before procedures do not produce homogeneous responses in subjects with different initial hydration status.

OBJECTIVES

The goal of this study was to compare the effect of standard and double intravenous (IV) infusion volumes in patients with low body fluid level, assessed by using bioimpedance vector analysis (BIVA), on the incidence of CI-AKI after elective coronary angiographic procedures.

METHODS

A total of 303 patients with low BIVA level on admission were randomized to receive standard volume saline (1 ml/kg/h for 12 h before and after the procedure) or double volume saline (2 ml/kg/h). Patients (n = 715) with an optimal BIVA level received standard volume saline and were included in a prospective registry. The saline infusion was halved in all patients with an ejection fraction <40%. BIVA was repeated immediately before the angiographic procedure in all patients. CI-AKI was defined as an increase in levels of cystatin C ≥10% above baseline at 24 h after contrast administration.

RESULTS

The incidence of CI-AKI was significantly lower (11.5% vs. 22.3%; p = 0.015) in patients receiving double volume saline than in those receiving standard volume saline, respectively. Before the angiographic procedure, 50% of the double volume patients achieved the optimal BIVA level compared with only 27.7% in the standard group (p = 0.0001). The findings were consistent in all the pre-specified subgroups excluding patients with a left ventricular ejection fraction <40% (p for interaction = 0.01).

CONCLUSIONS

Evaluation of BIVA levels on admission in patients with stable coronary artery disease allows adjustment of intravascular volume expansion, resulting in lower CI-AKI occurrence after angiographic procedures. (Personalized Versus Standard Hydration for Prevention of CI-AKI: A Randomized Trial With Bioimpedance Analysis; NCT02225431).

Classification of Hydration in Clinical Conditions: Indirect and Direct Approaches Using Bioimpedance

Although the need to assess hydration is well recognized, laboratory tests and clinical impressions are impractical and lack sensitivity, respectively, to be clinically meaningful. Different approaches use bioelectrical impedance measurements to overcome some of these limitations and aid in the classification of hydration status. One indirect approach utilizes single or multiple frequency bioimpedance in regression equations and theoretical models, respectively, with anthropometric measurements to predict fluid volumes (bioelectrical impedance spectroscopy-BIS) and estimate fluid overload based on the deviation of calculated to reference extracellular fluid volume. Alternatively, bioimpedance vector analysis (BIVA) uses direct phase-sensitive measurements of resistance and reactance, measured at 50 kHz, normalized for standing height, then plotted on a bivariate graph, resulting in a vector with length related to fluid content, and direction with phase angle that indexes hydration status. Comparison with healthy population norms enables BIVA to classify (normal, under-, and over-) and rank (change relative to pre-treatment) hydration independent of body weight. Each approach has wide-ranging uses in evaluation and management of clinical groups with over-hydration with an evolving emphasis on prognosis. This review discusses the advantages and limitations of BIS and BIVA for hydration assessment with comments on future applications.

Bioimpedance and New-Onset Heart Failure: A Longitudinal Study of >500 000 Individuals From the General Population

Background

Heart failure constitutes a high burden on patients and society, but although lifetime risk is high, it is difficult to predict without costly or invasive testing. We aimed to establish new risk factors of heart failure, which potentially could enable early diagnosis and preemptive treatment.

Methods and Results

We applied machine learning in the UK Biobank in an agnostic search of risk factors for heart failure in 500 451 individuals, excluding individuals with prior heart failure. Novel factors were then subjected to several in‐depth analyses, including multivariable Cox models of incident heart failure, and assessment of discrimination and calibration. Machine learning confirmed many known and putative risk factors for heart failure and identified several novel candidates. Mean reticulocyte volume appeared as one novel factor and leg bioimpedance another, the latter appearing as the most important new marker. Leg bioimpedance was lower in those who developed heart failure during an up to 9.8‐year follow‐up. When adjusting for known heart failure risk factors, leg bioimpedance was inversely related to heart failure (hazard ratio [95% confidence interval], 0.60 [0.48–0.73] and 0.75 [0.59–0.94], in age‐ and sex‐adjusted and fully adjusted models, respectively, comparing the upper versus lower quartile). A model including leg bioimpedance, age, sex, and self‐reported history of myocardial infarction showed good discrimination for future heart failure hospitalization (Concordance index [C‐index]=0.82) and good calibration.

Conclusions

Leg bioimpedance is inversely associated with heart failure incidence in the general population. A simple model of exclusively noninvasive measures, combining leg bioimpedance with history of myocardial infarction, age, and sex provides accurate predictive capacity.

What's Next for Acute Heart Failure Research?

Each year over one million patients with acute heart failure (AHF) present to a United States emergency department (ED). The vast majority are hospitalized for further management. The length of stay and high postdischarge event rate in this cohort have changed little over the past decade. Therapeutic trials have failed to yield substantive improvement in postdischarge outcomes; subsequently, AHF care has changed little in the past 40 years. Prior research studies have been fragmented as either "inpatient" or "ED-based." Recognizing the challenges in identification and enrollment of ED patients with AHF, and the lack of robust evidence to guide management, an AHF clinical trials network was developed. This network has demonstrated, through organized collaboration between cardiology and emergency medicine, that many of the hurdles in AHF research can be overcome. The development of a network that supports the collaboration of acute care and HF researchers, combined with the availability of federally funded infrastructure, will facilitate more efficient conduct of both explanatory and pragmatic trials in AHF. Yet many important questions remain, and in this document our group of emergency medicine and cardiology investigators have identified four high-priority research areas.

Noninvasive Bioelectrical Impedance for Predicting Clinical Outcomes in Outpatients With Heart Failure

BACKGROUND

Noninvasive bioelectrical impedance analysis (BIA) has shown promise in acute heart failure (HF) management. To our knowledge, its use in predicting outcomes in outpatients with chronic HF patients has not been well described.

METHODS AND RESULTS

BIA assessment of edema index was performed in 359 outpatients with HF using the InBody 520 scale. Edema index was calculated by dividing extracellular by total body water. Patients were stratified into those with low (≤0.39) and high (>0.39) edema indices. The outcome of interest was death, urgent transplant, or ventricular assist device over 2-year follow up. Patients with a high edema index were older, had higher B-type natriuretic peptide values and New York Heart Association Class. Patients with a high edema index had poorer outcomes (unadjusted hazard ratio 1.90, 95% confidence intervals 1.05-3.56). However, in multivariate analyses, a high edema index was not an independent predictor of outcomes (adjusted hazard ratio 1.21, 95% confidence interval 0.51-2.90).

CONCLUSIONS

A high edema index using a bioimpedance scale in a HF clinic correlated with patient outcomes in unadjusted analyses, but was not a predictor of outcomes once other measures of HF severity are accounted for. As a noninvasive measure of volume status, use of BIA in a HF clinic may be beneficial in determining patient prognosis and treatment when other outcome predictors are not immediately available.

Usefulness of combining admission brain natriuretic peptide (BNP) plus hospital discharge bioelectrical impedance vector analysis (BIVA) in predicting 90 days cardiovascular mortality in patients with acute heart failure

Heart failure is a disease characterized by high prevalence and mortality, and frequent rehospitalizations. The aim of this study is to investigate the prognostic power of combining brain natriuretic peptide (BNP) and congestion status detected by bioelectrical impedance vector analysis (BIVA) in acute heart failure patients. This is an observational, prospective, and a multicentre study. BNP assessment was measured upon hospital arrival, while BIVA analysis was obtained at the time of discharge. Cardiovascular deaths were evaluated at 90 days by a follow up phone call. 292 patients were enrolled. Compared to survivors, BNP was higher in the non-survivors group (mean value 838 vs 515 pg/ml, p < 0.001). At discharge, BIVA shows a statistically significant difference in hydration status between survivors and non-survivors [respectively, hydration index (HI) 85 vs 74, p < 0.001; reactance (Xc) 26.7 vs 37, p < 0.001; resistance (R) 445 vs 503, p < 0.01)]. Discharge BIVA shows a prognostic value in predicting cardiovascular death [HI: area under the curve (AUC) 0.715, 95% confidence interval (95% CI) 0.65-0.76; p < 0.004; Xc: AUC 0.712, 95% CI 0.655-0.76, p < 0.007; R: AUC 0.65, 95% CI 0.29-0.706, p < 0.0247]. The combination of BIVA with BNP gives a greater prognostic power for cardiovascular mortality [combined receiving operating characteristic (ROC): AUC 0.74; 95% CI 0.68-0.79; p < 0.001]. In acute heart failure patients, higher BNP levels upon hospital admission, and congestion detected by BIVA at discharge have a significant predictive value for 90 days cardiovascular mortality. The combined use of admission BNP and BIVA discharge seems to be a useful tool for increasing prognostic power in these patients.

Bioelectrical impedance vector analysis and clinical outcomes in patients with acute heart failure

AIMS

Fluid overload is a hallmark in acute heart failure (AHF). Bioelectrical impedance vector analysis (BIVA) has emerged as a noninvasive method for quantifying patients' hydration. We aimed to evaluate the effect of BIVA hydration status (BHS) measured before discharge on mortality and rehospitalization for AHF.

METHODS

We included 369 consecutive patients discharged from the cardiology department from a third-level hospital with a diagnosis of AHF. On the basis of BHS, patients were grouped into three categories: hyper-hydration (>74.3%), normo-hydration (72.7-74.3%) and dehydration (<72.7%). Appropriate survival techniques were used to evaluate the association between BHS and the risk of death and readmission for AHF.

RESULTS

At a median follow-up of 12 months (interquartile range, IQR: 5-19), 80 (21.7%) deaths and 93 (25.2%) readmissions for AHF were registered. The mortality and readmission rates for the BHS categories were hyper-hydration (3.28 and 3.83 per 10 persons-years); normo-hydration (1.43 and 2.68 per 10 persons-years); and dehydration (2.24 and 2.53 per 10 persons-years) (P < 0.05 for all comparisons). In an adjusted analysis, BHS displayed a significant association with mortality (P = 0.004), with a higher mortality risk in those with hyperhydration. Likewise, BHS showed to linearly predict AHF-readmission risk [hazard ratio 1.06 (1.03-1.10); P = 0.001 per increase in 1%].

CONCLUSION

In patients admitted with AHF, BHS assessed before discharge was independently associated with the risk of death and AHF-readmission.

Clinical and Research Considerations for Patients With Hypertensive Acute Heart Failure: A Consensus Statement from the Society for Academic Emergency Medicine and the Heart Failure Society of America Acute Heart Failure Working Group

Management approaches for patients in the emergency department (ED) who present with acute heart failure (AHF) have largely focused on intravenous diuretics. Yet, the primary pathophysiologic derangement underlying AHF in many patients is not solely volume overload. Patients with hypertensive AHF (H-AHF) represent a clinical phenotype with distinct pathophysiologic mechanisms that result in elevated ventricular filling pressures. To optimize treatment response and minimize adverse events in this subgroup, we propose that clinical management be tailored to a conceptual model of disease that is based on these mechanisms. This consensus statement reviews the relevant pathophysiology, clinical characteristics, approach to therapy, and considerations for clinical trials in ED patients with H-AHF.

Diagnosing Acute Heart Failure in the Emergency Department: A Systematic Review and Meta-analysis

BACKGROUND

Acute heart failure (AHF) is one of the most common diagnoses assigned to emergency department (ED) patients who are hospitalized. Despite its high prevalence in the emergency setting, the diagnosis of AHF in ED patients with undifferentiated dyspnea can be challenging.

OBJECTIVES

The primary objective of this study was to perform a systematic review and meta-analysis of the operating characteristics of diagnostic elements available to the emergency physician for diagnosing AHF. Secondary objectives were to develop a test-treatment threshold model and to calculate interval likelihood ratios (LRs) for natriuretic peptides (NPs) by pooling patient-level results.

METHODS

PubMed, EMBASE, and selected bibliographies were searched from January 1965 to March 2015 using MeSH terms to address the ability of the following index tests to predict AHF as a cause of dyspnea in adult patients in the ED: history and physical examination, electrocardiogram, chest radiograph (CXR), B-type natriuretic peptide (BNP), N-terminal proB-type natriuretic peptide (NT-proBNP), lung ultrasound (US), bedside echocardiography, and bioimpedance. A diagnosis of AHF based on clinical data combined with objective test results served as the criterion standard diagnosis. Data were analyzed using Meta-DiSc software. Authors of all NP studies were contacted to obtain patient-level data. The Quality Assessment Tool for Diagnostic Accuracy Studies-2 (QUADAS-2) for systematic reviews was utilized to evaluate the quality and applicability of the studies included.

RESULTS

Based on the included studies, the prevalence of AHF ranged from 29% to 79%. Index tests with pooled positive LRs ≥ 4 were the auscultation of S3 on physical examination (4.0, 95% confidence interval [CI] = 2.7 to 5.9), pulmonary edema on both CXR (4.8, 95% CI = 3.6 to 6.4) and lung US (7.4, 95% CI = 4.2 to 12.8), and reduced ejection fraction observed on bedside echocardiogram (4.1, 95% CI = 2.4 to 7.2). Tests with low negative LRs were BNP < 100 pg/mL (0.11, 95% CI = 0.07 to 0.16), NT-proBNP < 300 pg/mL (0.09, 95% CI = 0.03 to 0.34), and B-line pattern on lung US LR (0.16, 95% CI = 0.05 to 0.51). Interval LRs of BNP concentrations at the low end of "positive" results as defined by a cutoff of 100 pg/mL were substantially lower (100 to 200 pg/mL; 0.29, 95% CI = 0.23 to 0.38) than those associated with higher BNP concentrations (1000 to 1500 pg/mL; 7.12, 95% CI = 4.53 to 11.18). The interval LR of NT-proBNP concentrations even at very high values (30,000 to 200,000 pg/mL) was 3.30 (95% CI = 2.05 to 5.31).

CONCLUSIONS

Bedside lung US and echocardiography appear to the most useful tests for affirming the presence of AHF while NPs are valuable in excluding the diagnosis.

Assessment and prevalence of pulmonary oedema in contemporary acute heart failure trials: a systematic review

AIMS

Pulmonary oedema is a common and important finding in acute heart failure (AHF). We conducted a systematic review to describe the methods used to assess pulmonary oedema in recent randomized AHF trials and report its prevalence in these trials.

METHODS AND RESULTS

Of 23 AHF trials published between 2002 and 2013, six were excluded because they were very small or not randomized, or missing full-length publications. Of the remaining 17 (n = 200-7141) trials, six enrolled patients with HF and reduced ejection fraction (HF-REF) and 11, patients with both HF-REF and HF with preserved ejection fraction (HF-PEF). Pulmonary oedema was an essential inclusion criterion, in most trials, based upon findings on physical examination ('rales'), radiographic criteria ('signs of congestion'), or both. The prevalence of pulmonary oedema in HF-REF trials ranged from 75% to 83% and in combined HF-REF and HF-PEF trials from 51% to 100%. Five trials did not report the prevalence or extent of pulmonary oedema assessed by either clinical examination or chest x-ray. Improvement of pulmonary congestion with treatment was inconsistently reported and commonly grouped with other signs of congestion into a score. One trial suggested that patients with rales over >2/3 of the lung fields on admission were at higher risk of adverse outcomes than those without.

CONCLUSION

Although pulmonary oedema is a common finding in AHF, represents a therapeutic target, and may be of prognostic importance, recent trials used inconsistent criteria to define it, and did not consistently report its severity at baseline or its response to treatment. Consistent and ideally quantitative, methods for the assessment of pulmonary oedema in AHF trials are needed.

From the nephrologist's point of view: diversity of causes and clinical features of acute kidney injury

Acute kidney injury (AKI) is a clinical syndrome with multiple entities. Although AKI implies renal damage, functional impairment or both, diagnosis is solely based on the functional parameters of serum creatinine and urine output. The latest definition was provided by the Kidney Disease Improving Global Outcomes (KDIGO) working group in 2012. Independent of the underlying disease, and even in the case of full recovery, AKI is associated with an increased morbidity and mortality. Awareness of the patient's individual risk profile and the diversity of causes and clinical features of AKI is pivotal for optimization of prophylaxes, diagnosis and therapy of each form of AKI. A differentiated and individualized approach is required to improve patient mortality, morbidity, long-term kidney function and eventually the quality of life. In this review, we provide an overview of the different clinical settings in which specific forms of AKI may occur and point out possible diagnostic as well as therapeutic approaches. Secifically AKI is discussed in the context of non-kidney organ failure, organ transplantation, sepsis, malignancy and autoimmune disease.

[Key messages for the initial management of the elderly patient with acute heart failure]

Acute heart failure is a high prevalence geriatric syndrome that has become one of the most frequent causes of visits to emergency departments, as well as hospital admission, and is associated with high morbidity, mortality and functional impairment. There has been an increasing amount of information published in recent years on the initial management of acute heart failure and the results of the short-term outcomes, as well as the natural history of the disease. The objective of this study is to provide several recommendations that should be taken into account in the initial management of the elderly patient with acute heart failure in the emergency departments, and to review the most interesting currently on-going clinical trials.

Biomarkers for risk prediction in acute decompensated heart failure

Risk prediction in patients admitted with acute decompensated heart failure (ADHF) remains a challenge. Biomarkers may improve risk prediction, which in turn may help to better inform patients regarding short-term and long-term prognosis, therapy and care. Most data on biomarkers have been derived from patient cohorts with chronic heart failure. In ADHF, currently, risk tools largely rely on common clinical and biochemical parameters. However, ADHF is not a single disease. It presents in various manners and different etiologies may underlie ADHF, which are reflected by different biomarkers. In the last decade, many studies have reported the prognostic value of these biomarkers. These studies have attempted to describe a value for statistical modeling, e.g., reclassification indices, in an effort to report incremental value over a clinical model or the "gold standard". However, the overall incremental predictive value of biomarkers has been modest compared to already existing clinical models. Natriuretic peptides, e.g., (NTpro-)BNP, are the benchmark, but head-to-head comparisons show that there are novel biomarkers with comparable prognostic value. Multimarker strategies may provide superior risk stratification. Future studies should elucidate cost-effectiveness of single or combined biomarker testing. The purpose of this review was to provide an update on current biomarkers and to identify new promising biomarkers than can be used in prognostication of acute heart failure.

Usefulness of combining galectin-3 and BIVA assessments in predicting short- and long-term events in patients admitted for acute heart failure

Introduction. Acute heart failure (AHF) is associated with a higher risk for the occurrence of rehospitalization and death. Galectin-3 (GAL3) is elevated in AHF patients and is an indicator in predicting short-term mortality. The total body water using bioimpedance vector analysis (BIVA) is able to identify mortality within AHF patients. The aim of this study was to evaluate the short- and long-term predictive value of GAL3, BIVA, and the combination of both in AHF patients in Emergency Department (ED). Methods. 205 ED patients with AHF were evaluated by testing for B type natriuretic peptide (BNP) and GAL3. The primary endpoint was death and rehospitalization at 30, 60, 90, and 180 days and 12 and 18 months. AHF patients were evaluated at the moment of ED arrival with clinical judgment and GAL3 and BIVA measurement. Results. GAL3 level was significantly higher in patients >71 years old, and with eGFR < 30 cc/min. The area under the curve (AUC) of GAL3 + BIVA, GAL3 and BIVA for death and rehospitalization both when considered in total and when considered serially for the follow-up period showed that the combination has a better prognostic value. Kaplan-Meier survival curve for GAL3 values >17.8 ng/mL shows significant survival difference. At multivariate Cox regression analysis GAL3 is an independent variable to predict death + rehospitalization with a value of 32.24 ng/mL at 30 days (P < 0.005). Conclusion. In patients admitted for AHF an early assessment of GAL3 and BIVA seems to be useful in identifying patients at high risk for death and rehospitalization at short and long term. Combining the biomarker and the device could be of great utility since they monitor the severity of two pathophysiological different mechanisms: heart fibrosis and fluid overload.