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.

Bioelectrical impedance vector analysis is different according to the comorbidity burden in post-acute myocardial infarction

BACKGROUND

The prevalence of a high comorbidity burden in patients who suffered an acute myocardial infarction (AMI) is increasing with the aging population, and the nutrition status also may be a predictor of clinical outcomes for these patients. This study aimed to investigate the relationship between the comorbidity burden and the characteristics of the bioelectrical impedance vector analysis (BIVA) in patients post-AMI.

METHODS

This prospective observational cohort study was conducted with adult patients who were hospitalized with AMI. Pre-existing comorbidities were assessed by the Charlson comorbidity index (CCI) adjusted by age, and anthropometric and BIVA characteristics were evaluated after the hemodynamic stabilization. All patients were followed-up until hospital discharge, and their length of stay was observed.

RESULTS

A total of 184 patients (75% were males; mean age, 60.2 ± 12.3 years) were included. The most common comorbidities were dyslipidemia (73.9%), hypertension (62%), and type 2 diabetes (34.2%). A higher CCI (≥3) was associated with sex (P = 0.008) and age (P < 0.001). Regarding BIVA, statistically significant differences were detected between sex (P < 0.001), age (P < 0.001), and CCI (P = 0.003), with longer vectors in female, older adults, and those with CCI ≥ 3.

CONCLUSION

Finding a relationship between BIVA and CCI suggests the first identified coherent differences, potentially correlated with diseases, representing a first contribution to support this type of assessment. Therefore, with BIVA, healthcare professionals may monitor abnormalities and adopt preventive nutrition care measures on patients post-AMI to improve their clinical status.

Cardiorenal Syndrome in the Hospital

The cardiorenal syndrome refers to a group of complex, bidirectional pathophysiological pathways involving dysfunction in both the heart and kidney. Upward of 60% of patients admitted for acute decompensated heart failure have CKD, as defined by an eGFR of <60 ml/min per 1.73 m 2 . CKD, in turn, is one of the strongest risk factors for mortality and cardiovascular events in acute decompensated heart failure. Although not well understood, the mechanisms in the cardiorenal syndrome include venous congestion, arterial underfilling, neurohormonal activation, inflammation, and endothelial dysfunction. Arterial underfilling may lead to activation of the renin-angiotensin-aldosterone system and sympathetic nervous system, leading to sodium reabsorption and vasoconstriction. Venous congestion likely also mediates and perpetuates these maladaptive pathways. To rule out intrinsic kidney disease that is distinct from the cardiorenal syndrome, one should obtain a careful history, review longitudinal eGFR trends, assess albuminuria and proteinuria, and review the urine sediment and kidney imaging. The hallmark of the cardiorenal syndrome is intense sodium avidity and diuretic resistance, often requiring a combination of diuretics with varying pharmacological targets, and monitoring of urinary response to guide escalations in therapy. Invasive means of decongestion may be required including ultrafiltration or KRT such as peritoneal dialysis, which is often better tolerated from a hemodynamic perspective than intermittent hemodialysis. Strategies for increasing forward perfusion in states of low cardiac output and cardiogenic shock may include afterload reduction and inotropes and, in the most severe cases, mechanical circulatory support devices, many of which have kidney-specific considerations.

The Usefulness of Bioelectrical Impedance as a Marker of Fluid Status in Patients With Congestive Heart Failure: A Systematic Review and Meta-Analysis

Bioelectrical impedance analysis (BIA) is a method that measures electrical currents conducted through water, which assesses fluid status by measuring extracellular water (ECW), total body water (TBW), and resistance (R). Limited studies are done to evaluate the utility of BIA in patients with congestive heart failure (CHF), and therefore, we performed a systematic review and meta-analysis to evaluate this. A comprehensive literature search was performed at Medline and Embase until March 2022. Our primary outcome was a comparison of TBW and ECW between patients with CHF and controls. Our secondary outcome was to compare R between the groups. All analysis was conducted using RevMan 5.4 software. Six studies with 1,046 patients met our inclusion criteria. Out of 1,046 patients, 526 had CHF and 538 had no CHF. Among patients with CHF, all 526 had decompensated CHF. There was no significant difference in TBW between patients with heart failure and the control group (mean deviation (MD) = 1.42 (-0.44-3.27), percent of variation (I2) = 0%, p = 0.13). ECW was significantly higher with an assessment of BIA in heart failure patients compared to patients in the control group (MD = 1.62 (0.82-2.42), I2 = 0%, p < 0.0001). Resistance of extracellular fluid was significantly lower in the heart failure group (MD = -45.64 (-72.88--18.41), I2 = 83%, p = 0.001). Publication bias was deferred as the number of included studies was less than 10. BIA can be helpful in ambulatory and inpatient setting to identify patients' fluid status, which can improve outcomes. However, larger prospective studies are needed to further evaluate the usefulness of BIA in the CHF population.

[Risk Assessment of Adverse Outcomes in Symptomatic Patients With Arterial Hypertension and Chronic Heart Failure With Preserved Ejection Fraction Using THE HFA-PEFF Algorithm]

Aim      To study the incidence of heart failure (HF) in patients with arterial hypertension (AH), symptoms of HF, and left ventricular ejection fraction (LV EF) ≥50 % using a novel, modified HFA-PEFF diagnostic algorithm and to evaluate the liver hydration status and density depending on the established HF profiles and the prognostic significance of this algorithm.Material and methods  This study included 180 patients (median age, 72 years) with AH, symptoms of HF, and LV EF ≥50 %. The incidence of chronic HF with preserved ejection fraction (CHFpEF) was studied with the stepwise, modified HFA-PEFF diagnostic algorithm, and long-term outcomes were assessed at 3, 6, and 12 months of follow-up. The hydration status was determined by a bioimpedance vector analysis, and the liver density was measured by indirect fibroelastometry. The following tests were performed for all patients: standard, general clinical and laboratory examination with evaluation of CH symptoms (including N-terminal pro-brain natriuretic peptide test); extended echocardiography with assessment of structural and functional parameters of the heart; a KCCQ questionnaire was used for evaluation of patients' condition and quality of life (QoL). Long-term outcomes were studied by phone calls at 3, 6, and 12 months following discharge from the hospital/visit (worsened QoL, repeated hospitalization for cardiovascular causes, cardiovascular death or all-cause death).Results The following profiles were determined by the HFA-PEFF algorithm: with CHFpEF, with intermediate probability of HF, and without HF (58.9, 31.1, and 10 %, respectively). The study showed that patients with CHFpEF compared to patients of the intermediate group and without HF, had higher levels of brain natriuretic peptide, more pronounced signs of congestion according to results of the bioimpedance vector analysis and a higher liver density according to results of indirect fibroelastometry of the liver, which allowed identification of a group of patients with a high probability of CHFpEF. The diagnosis of HF by HFA-PEFF had an adverse prognostic significance with respect of worsened QoL according to the KCCQ questionnaire, and of repeated admission for HF during a year.Conclusion      In AH patients with symptoms of HF and LV EF ≥50 %, CHFpEF was detected with the HFA-PEFF algorithm in 58.9 % of cases. Patients with AH and verified CHFpEF had a high incidence of hyperhydration and increased liver density. A diagnosis of CHFpEF by the HFA-PEFF algorithm had an adverse prognostic significance with respect of long-term outcomes.

Pathophysiology, Functional Assessment and Prognostic Implications of Nutritional Disorders in Systemic Amyloidosis

Gastrointestinal involvement is a common clinical feature of patients with systemic amyloidosis. This condition is responsible for invalidating gastrointestinal symptoms, a significant macro and micronutrient deficit, and is a marker of disease severity. Gastrointestinal involvement should be actively sought in patients with systemic amyloidosis, while its diagnosis is challenging in patients with isolated gastrointestinal symptoms. The nutritional status in systemic amyloidosis plays an essential role in the clinical course and is considered a significant prognostic factor. However, the definition of nutritional status is still challenging due to the lack of internationally accepted thresholds for anthropometric and biochemical variables, especially in specific populations such as those with systemic amyloidosis. This review aims to elucidate the fundamental steps for nutritional assessment by using clinical and instrumental tools for better prognostic stratification and patient management regarding quality of life and outcomes.

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 dialysis populations, but data from heart failure or non-dialysis chronic kidney disease (CKD) populations have not.

METHODS AND RESULTS

We conducted a systematic review of studies using whole-body bioimpedance from heart failure and non-dialysis CKD populations which reported associations with mortality, cardiovascular outcomes and/or CKD progression. We searched MEDLINE, Embase databases and the Cochrane CENTRAL registry from inception to 14^th March 2022. Thirty one eligible studies were identified: 20 heart failure and 11 CKD cohorts, with 2 studies including over 1000 participants. A wide range of different 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 modelling approaches precluded meta-analysis. The largest identified study was in non-dialysis CKD (Chronic Renal Insufficiency Cohort, 3751 participants) which reported adjusted hazard ratios (95% confidence intervals) for phase angle <5.59 versus ≥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 needs 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.

Congestive nephropathy: a neglected entity? Proposal for diagnostic criteria and future perspectives

Venous congestion has emerged as an important cause of renal dysfunction in patients with cardiorenal syndrome. However, only limited progress has been made in differentiating this haemodynamic phenotype of renal dysfunction, because of a significant overlap with pre-existing renal impairment due to long-term hypertension, diabetes, and renovascular disease. We propose congestive nephropathy (CN) as this neglected clinical entity. CN is a potentially reversible subtype of renal dysfunction associated with declining renal venous outflow and progressively increasing renal interstitial pressure. Venous congestion may lead to a vicious cycle of hormonal activation, increased intra-abdominal pressure, excessive renal tubular sodium reabsorption, and volume overload, leading to further right ventricular (RV) stress. Ultimately, renal replacement therapy may be required to relieve diuretic-resistant congestion. Effective decongestion could preserve or improve renal function. Congestive acute kidney injury may not be associated with cellular damage, and complete renal function restoration may be a confirmatory diagnostic criterion. In contrast, a persistently low renal perfusion pressure might induce renal dysfunction and histopathological lesions with time. Thus, urinary markers may differ. CN is mostly seen in biventricular heart failure but may also occur secondary to pulmonary arterial hypertension and elevated intra-abdominal pressure. An increase in central venous pressure to >6 mmHg is associated with a steep decrease in glomerular filtration rate. However, the central venous pressure range that can provide an optimal balance of RV and renal function remains to be determined. We propose criteria to identify cardiorenal syndrome subgroups likely to benefit from decongestive or pulmonary hypertension-specific therapies and suggest areas for future research.

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.

Comparison of Bioelectrical Impedance Analysis Parameters for the Detection of Fluid Overload in the Prediction of Mortality in Patients Admitted at the Emergency Department

BACKGROUND

Fluid overload (FO) in critically ill patients is associated with increased adverse events. This study aims to compare different bioelectrical impedance analysis (BIA) parameters that demonstrate FO and their association with 30-day mortality in critical patients admitted to the emergency department (ED).

METHODS

Five components of the BIA were obtained by multifrequency device-total body water (TBW), extracellular water (ECW), intracellular water (ICW), resistance (R), and reactance (Xc)-to calculate parameters (impedance vectors, impedance ratio, and the ratios of ECW to TBW, ECW to ICW, ECW to body surface area, TBW to height² , ICW to height² , Xc to height, and R to height) that have been used for the detection of FO. A concordance analysis (κ) was performed comparing every parameter with each other. Furthermore, different regression models (Cox regression) were created associating the FO for each parameter with 30-day mortality, adjusted for age, body mass index, sex, Sequential Organ Failure Assessment score, and serum albumin level.

RESULTS

A total of 142 patients were included in the study. Only FO by impedance vector analysis (relative risk [RR] = 6.4; 95% CI, 1.5-27.9; P = .01), impedance ratio (RR = 2.7; 95% CI, 1.1-7.1; P = .04), and R (RR = 2.6; 95% CI, 1.2-5.5; P = .02) increased the probability of 30-day mortality.

CONCLUSIONS

Different parameters that determine FO by BIA were associated with the mortality of patients admitted to the ED, but the impedance vector analysis was superior to any other parameter of the BIA.

Prognostic Value of Both Plasma Volume Status and Nutritional Status in Patients With Severely Decompensated Acute Heart Failure

BACKGROUND

Plasma volume status (PVS) has been evaluated recently as a prognostic marker of acute heart failure (AHF). However, whether evaluating PVS alone is sufficient remains unclear.

METHODS

Of 675 patients with AHF screened, 601 were enrolled. The PVS, prognostic nutritional index (PNI) (lower = worse), and Controlling Nutritional Status (CONUT) score (higher = worse) were evaluated. Patients were divided into 2 groups according to PVS value (low- or high-PVS group) and were further subdivided into 4 groups (low- or high-PVS/CONUT group and low- or high-PVS/PNI group).

RESULTS

A Kaplan-Meier curve showed a significantly lower survival rate in the high-PVS group than in the low-PVS group, the high-PVS/high-CONUT group than in the high-PVS/low-CONUT group, and the high-PVS/low-PNI group than in the high-PVS/high-PNI group. A multivariate Cox regression model showed that high PVS (hazard ratio [HR], 1.642; 95% confidence interval [CI], 1.049-2.570) and high PVS/high CONUT (HR, 2.076; 95% CI, 1.147-3.757) and high PVS/low PNI (HR, 2.094; 95% CI, 1.166-3.761) were independent predictors of 365-day mortality.

CONCLUSIONS

An adverse outcome was predicted by the evaluation of PVS; furthermore, a malnutrition status with a high PVS leads to an adverse outcome. The simultaneous evaluation of nutrition status and PVS is essential to predict an AHF outcome.

Bioimpedance vector analysis predicts hospital length of stay in acute heart failure

OBJECTIVE

Congestion in acute heart failure (AHF) affects survival curves and hospital length of stay (LOS). The evaluation of congestion, however, is not totally objective. The aim of this study was to verify the accuracy of bioelectrical impedance vector analysis (BIVA) in predicting the LOS in AHF patients.

METHODS

This is a retrospective study. A total of 706 patients (367 male; mean age: 78 ± 10 y) who had been admitted to hospital with an AHF event were enrolled. All underwent anthropometric and clinical evaluation, baseline transthoracic echocardiography, and biochemical and BIVA evaluations.

RESULTS

The comparison among the clinical characteristics of congestion, LOS, and hyperhydration status revealed that the higher the hydration status, the longer the LOS (from 7.36 d [interquartile range: 7.34-7.39 d] in normohydrated patients to 9.04 d [interquartile range: 8.85- 9.19 d] in severe hyperhydrated patients; P < 0.05). At univariate analysis, brain natriuretic peptide, blood urea nitrogen, New York Heart Association class, hemoglobin, hydration index, and peripheral edema all had a statistically significant influence on LOS. At multivariate analysis, only brain natriuretic peptide (P < 0.0001), blood urea nitrogen (P = 0.011), and hydration index (P < 0.0001) were significantly associated to LOS.

CONCLUSIONS

Congestion evaluated by BIVA is an independent predictor of length of total hospital stay in HF patients with acute decompensation. The quick and reliable detection of congestion permits the administration of target therapy for AHF, thus reducing LOS and treatment costs.

Complex assessment of patients with decompensated heart failure: The clinical value of impedance cardiography and N-terminal pro-brain natriuretic peptide

BACKGROUND

Acute decompensated heart failure (ADHF) is a serious clinical problem and a condition requiring immediate diagnostics, supporting the therapeutic decision adequate to the specific ADHF mechanism. N-terminal pro-brain natriuretic peptide (NT-proBNP) is an established biochemical marker of heart failure, strongly related to hemodynamic status. Impedance cardiography (ICG) provides non-invasive hemodynamic assessment that can be performed immediately at the bedside and revealed to be useful diagnostic tool in some clinical settings in cardiology.

OBJECTIVES

The aim of this study was to evaluate the usefulness of ICG in the admission diagnostics and monitoring the effects of treatment in patients hospitalized due to ADHF, with special emphasis on its relation to NT-proBNP.

METHODS

This study enrolled 102 patients, aged over 18 years, hospitalized due to ADHF. The subjects underwent detailed clinical assessment, including ICG and NT-proBNP at admission and at discharge day.

RESULTS

Among all analyzed ICG parameters thoracic fluid content (TFC), a marker of chest overload, was the most significantly correlated with NT-proBNP level (R = 0.46; p = 0.000001). In comparison with patients with low thoracic fluid content (TFC ≤ 35/kΩ), those with higher TFC values (>35/kΩ) exhibited a greater severity of symptoms (NYHA functional class); higher NT-proBNP levels; lower left ventricular ejection fraction (LVEF), stroke index (SI), and cardiac index (CI); as well as significantly higher systemic vascular resistance index (SVRI). These TFC-based subgroups showed no significant differences in terms of heart rate (HR), systolic blood pressure (SBP), or diastolic blood pressure (DBP).

CONCLUSIONS

The evaluation of hemodynamic parameters, especially TFC, seems to be a worthwhile addition to standard diagnostics, both at the stage of hospital admission and while monitoring the effects of treatment. Impedance cardiography is a useful method in evaluating individual hemodynamic profiles in patients with ADHF.

Mortality in adult patients with fluid overload evaluated by BIVA upon admission to the emergency department

PURPOSE OF THE STUDY

The aim of this study was to investigate the association of fluid overload, measured by bioelectrical impedance vector analysis (BIVA) and also by accumulated fluid balance, with 30-day mortality rates in patients admitted to the emergency department (ED).

DESIGN

We conducted a prospective observational study of fluid overload using BIVA, taking measures using a multiple-frequency whole-body tetrapolar equipment. Accumulated fluid balances were obtained at 24, 48 and 72 hours from ED admission and its association with 30-day mortality.

PATIENTS

109 patients admitted to the ED classified as fluid overloaded by both methods.

RESULTS

According to BIVA, 71.6% (n=78) of patients had fluid overload on ED admission. These patients were older and had higher Sequential Organ Failure Assessment scores. During a median follow-up period of 30 days, 32.1% (n=25) of patients with fluid overload evaluated by BIVA died versus none with normovolaemia (p=0.001). There was no statistically significant difference in mortality between patients with and without fluid overload as assessed by accumulated fluid balance (p=0.81).

CONCLUSIONS

Fluid overload on admission evaluated by BIVA was significantly related to mortality in patients admitted to the ED.

Involvement of systemic venous congestion in heart failure

Systemic venous congestion has gained significant importance in the interpretation of the pathophysiology of acute heart failure, especially in the development of renal function impairment during exacerbations. In this study, we review the concept, clinical characterisation and identification of venous congestion. We update current knowledge on its importance in the pathophysiology of acute heart failure and its involvement in the prognosis. We pay special attention to the relationship between abdominal congestion, the pulmonary interstitium as filtering membrane, inflammatory phenomena and renal function impairment in acute heart failure. Lastly, we review decongestion as a new therapeutic objective and the measures available for its assessment.