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

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.

The role of bioelectrical phase angle in patients with heart failure

The most challenging feature of heart failure (HF) still remains the evaluation of congestion. Residual congestion at discharge and the difficulties in perfectly dosing therapies in order to balance the hydration status of the patient are the most worrisome issues when dealing with HF.The use of bioimpedance vector analysis (BIVA) might promote a different approach in the general management of patients with HF. BIVA is a reliable, fast, bedside tool able to assess the congestion status. It proved to be helpful to physicians for diagnosing congestive status, managing therapies, and providing prognostic information in the setting of HF.Bioelectrical Phase Angle (PhA) - as derived from equations related to the parameters of BIVA - recently surged as a possible biomarker for patients with HF. Studies provided data about the application of PhA in the clinical management and in the overall risk stratification of HF patients.Basically, the use of PhA might be considered as a holistic evaluation of patients with HF which includes the need for a multiparametric approach able to effectively depict the clinical status of patients. There is no definite biomarker able to comprehensively describe and identify all the features of HF patient, but scores based on molecules/techniques able to explore the different pathogenetic mechanisms of HF are desirable.The aim of this review was to provide a comprehensive evaluation of literature related to PhA role in HF and the impact of this biomarker on clinical management and risk stratification of HF 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.

The intracellular fluid compartment is smaller than commonly believed when measured by whole-body bioimpedance

OBJECTIVES

To report our data on the total body water (TBW), intracellular volume (ICV), extracellular volume (ECV), and fat-free mass (FFM) from studies using whole-body bioimpedance (BIA) with the aim of contrasting them to commonly cited reference values.

METHODS

Data were retrospectively retrieved from three single-center studies of adult healthy male volunteers and one study of women scheduled for abdominal hysterectomy where multifrequency BIA had been applied to obtain measurements of TBW, ICV, ECV, and FFM.

RESULTS

Based on measurements performed in 44 males, the TBW, ICV, ECV, and FFM represented 49.1 (4.9)%, 23.32 (3.1)%, 25.8 (2.2)%, and 67.4 (7.4)% of the BW, respectively (mean, SD). In 15 females, these volumes were 40.4 (4.5)%, 18.0 (2.1)%, 22.4 (2.6)%, and 55.6 (6.1)% per kg BW, respectively. The deviation of these measurements from the reference values increased linearly with body weight and age.

CONCLUSIONS

Body fluid volumes indicated by BIA showed that TBW amounted to 80% of the reference volume, which is 60% per kg BW in adult males. The ratio between the ICV and the ECV was approximately 1:1, while this ratio is traditionally reported to be 2:1.

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.

Maternal Low Volume Circulation Relates to Normotensive and Preeclamptic Fetal Growth Restriction

This narrative review summarizes current evidence on the association between maternal low volume circulation and poor fetal growth. Though much work has been devoted to the study of cardiac output and peripheral vascular resistance, a low intravascular volume may explain why high vascular resistance causes hypertension in women with preeclampsia (PE) that is associated with fetal growth restriction (FGR) and, at the same time, presents with normotension in FGR itself. Normotensive women with small for gestational age babies show normal gestational blood volume expansion superimposed upon a constitutionally low intravascular volume. Early onset preeclampsia (EPE; occurring before 32 weeks) is commonly associated with FGR, and poor plasma volume expandability may already be present before conception, thus preceding gestational volume expansion. Experimentally induced low plasma volume in rodents predisposes to poor fetal growth and interventions that enhance plasma volume expansion in FGR have shown beneficial effects on intrauterine fetal condition, prolongation of gestation and birth weight. This review makes the case for elevating the maternal intravascular volume with physical exercise with or without Nitric Oxide Donors in FGR and EPE, and evaluating its role as a potential target for prevention and/or management of these conditions.

Haemodynamic monitoring in acute heart failure - what you need to know

Acute heart failure (AHF) is a sudden, life-threatening condition, defined as a gradual or rapid onset of symptoms and/or signs of HF. AHF requires urgent medical attention, being the most frequent cause of unplanned hospital admission in patients above 65 years of age. AHF is associated with a 4–12% in-hospital mortality rate and a 21–35% 1-year mortality rate post-discharge. Considering the serious prognosis in AHF patients, it is very important to understand the mechanisms and haemodynamic status in an individual AHF patient, thus preventing end-organ failure and death. Haemodynamic monitoring is a serial assessment of cardiovascular function, intended to detect physiologic abnormalities at the earliest stages, determine which interventions could be most effective, and provide the basis for initiating the most appropriate therapy and evaluate its effects. Over the past decades, haemodynamic monitoring techniques have evolved greatly. Nowadays, they range from very invasive to non-invasive, from intermittent to continuous, and in terms of the provided parameters. Invasive techniques contain pulmonary artery catheterization and transpulmonary thermodilution. Minimally invasive techniques include oesophageal Doppler and noncalibrated pulse wave analysis. Non-invasive techniques contain echocardiography, bioimpedance, and bioreactance techniques as well as non-invasive pulse contour methods. Each of these techniques has specific indications and limitations. In this article, we aimed to provide a pathophysiological explanation of the physical terms and parameters used for haemodynamic monitoring in AHF and to summarize the working principles, advantages, and disadvantages of the currently used methods of haemodynamic monitoring.

Long Term Metabolic Effects of Sacubitril/Valsartan in Non-Diabetic and Diabetic Patients With Heart Failure Reduced Ejection Fraction: A Real Life Study

Sacubitril/Valsartan (sac/val) has improved clinical prognosis in patients affected by heart failure (HF) with reduced ejection fraction (HFrEF). HF and type 2 diabetes mellitus (T2DM) frequently coexist, with a prevalence of T2DM of 35%–40% in patients with HF. T2DM is the third co-morbidities in patients with HF and a strong independent risk factor for the progression of HF. In a post hoc analysis of PARADIGM-HF, improved glycemic control was shown in patients with T2DM and HFrEF receiving sac/val compared to enalapril at 12 months of follow-up. The aim of the present study was to evaluate, in a series of repeated observations in 90 HFrEF patients, the long term effect of sac/val treatment on renal function, glycometabolic state and insulin sensitivity parameters, according to diabetic status. We studied 90 patients (74 men and 16 women, mean age 68 ± 10 years, 60 diabetics and 30 non-diabetics) suffering from HFrEF and still symptomatic despite optimal pharmacological therapy. Patients with left ventricular ejection fraction (LVEF) <35% and II-III NYHA functional class were enrolled. All patients underwent clinical-instrumental and laboratory determinations and Minnesota Living with HF Questionnaire (MLHFQ) every 6 months until 30 months to evaluate benefits and adverse events. After 30 months follow-up, we observed a significant improvement in glycometabolic parameters including HbA1c, fasting glucose and insulin, insulin-like growth factor-1 (IGF-1), HOMA index, and LDL cholesterol. Moreover, renal function, NTpro-BNP levels and echocardiographic parameters significantly improved. In diabetic patients a significant reduction in use of oral antidiabetic drugs and insulin was observed after 30 months of sac/val treatment. In the whole population, multivariate analysis shows that the evolution of cardiac index (CI) was significantly associated to simultaneous changes in HOMA, IGF-1 and visit; per each visit and for 1 ng/ml increase in IGF-1 there was an increase in CI of 64.77 ml/min/m² (p < 0.0001) and 0.98 ml/min/m² (p = 0.003), respectively, whereas 1 point increase in HOMA was associated with a −7.33 ml/min/m2 (p = 0.003) reduction in CI. The present data confirm persistent metabolic improvement in patients with HFrEF after treatment with sac/val and highlights its potential therapeutical role in patients with metabolic comorbidities.

Renal Manifestations and their Association with Mortality and Length of Stay in COVID-19 Patients at a Safety-net Hospital

Background

Renal involvement in COVID-19 leads to severe disease and higher mortality. We study renal parameters in COVID-19 patients and their association with mortality and length of stay in hospital.

Methods

A retrospective study (n=340) of confirmed COVID-19 patients with renal involvement determined by the presence of acute kidney injury. Multivariate analyses of logistic regression for mortality and linear regression for length of stay (LOS) adjusted for relevant demographic, comorbidity, disease severity, and treatment covariates.

Results

Mortality was 54.4% and mean LOS was 12.9 days. For mortality, creatinine peak (OR:35.27, 95% CI:2.81, 442.06, p<0.01) and persistent renal involvement at discharge (OR:4.47, 95% CI:1.99,10.06, p<0.001) were each significantly associated with increased odds for mortality. Increased blood urea nitrogen peak (OR:0.98, 95%CI:0.97,0.996, p<0.05) was significantly associated with decreased odds for mortality. For LOS, increased blood urea nitrogen peak (B:0.001, SE:<0.001, p<0.01), renal replacement therapy (B:0.19, SE:0.06, p<0.01), and increased days to acute kidney injury (B:0.19, SE:0.05, p<0.001) were each significantly associated with increased length of stay.

Conclusion

Our study emphasizes the importance in identifying renal involvement parameters in COVID-19 patients. These parameters are associated with LOS and mortality, and may assist clinicians to prognosticate COVID-19 patients with renal involvement.

Respiratory failure and bioelectrical phase angle are independent predictors for long-term survival in acute heart failure

Background. The assessment of long-term mortality in acute decompensated heart failure (ADHF) is challenging. Respiratory failure and congestion play a fundamental role in risk stratification of ADHF patients. The aim of this study was to investigate the impact of arterial blood gases (ABG) and congestion on long-term mortality in patients with ADHF. Methods and results. We enrolled 252 patients with ADHF. Brain natriuretic peptide (BNP), blood urea nitrogen (BUN), phase angle as assessed by means of bioimpedance vector analysis, and ABG analysis were collected at admission. The endpoint was all-cause mortality. At a median follow-up of 447 d (interquartile range [IQR]: 248-667), 72 patients died 1-840 d (median 106, IQR: 29-233) after discharge. Respiratory failure types I and II were observed in 78 (19%) and 53 (20%) patients, respectively. The ROC analyses revealed that the cut-off points for predicting death were: BNP > 441 pg/mL, BUN > 1.67 mmol/L, partial pressure in oxygen (PaO₂) ≤69.7 mmHg_, and phase angle ≤4.9°. Taken together, these four variables proved to be good predictors for long-term mortality in ADHF (area under the curve [AUC] 0.78, 95% CI 0.72-0.78), thus explaining 60% of all deaths. A multiparametric score based on these variables was determined: each single-unit increase promoted a 2.2-fold augmentation of the risk for death (hazard ratio [HR] 2.2, 95% CI 1.8-2.8, p< .0001). Conclusions. A multiparametric approach based on measurements of BNP, BUN, PaO_2, and phase angle is a reliable approach for long-term prediction of mortality risk in patients with ADHF.

Sex Differences in the Evaluation of Congestion Markers in Patients with Acute Heart Failure

The impact of sex on the assessment of congestion in acute heart failure (AHF) is still a matter of debate. The objective of this analysis was to evaluate sex differences in the evaluation of congestion at admission in patients hospitalized for AHF. We consecutively enrolled 494 AHF patients (252 female). Clinical congestion assessment, B-type natriuretic peptide levels analysis, blood urea nitrogen to creatinine ratio (BUN/Cr), plasma volume status estimate (by means of Duarte or Kaplam-Hakim PVS), and hydration status evaluation through bioimpedance analysis were performed. There was no difference in medications between men and women. Women were older (79 ± 9 yrs vs. 77 ± 10 yrs, p = 0.005), and had higher left ventricular ejection fraction (45 ± 11% vs. 38 ± 11%, p < 0.001), and lower creatinine clearance (42 ± 25 mL/min vs. 47 ± 26 mL/min, p = 0.04). The prevalence of peripheral oedema, orthopnoea, and jugular venous distention were not significantly different between women and men. BUN/Cr (27 ± 9 vs. 23 ± 13, p = 0.04) and plasma volume were higher in women than men (Duarte PVS: 6.0 ± 1.5 dL/g vs. 5.1 ± 1.5 dL/g, p < 0.001; Kaplam−Hakim PVS: 7.9 ± 13% vs. −7.3 ± 12%, p < 0.001). At multivariate logistic regression analysis, female sex was independently associated with BUN/Cr and PVS. Female sex was independently associated with subclinical biomarkers of congestion such as BUN/Cr and PVS in patients with AHF. A sex-guided approach to the correct evaluation of patients with AHF might become the cornerstone for the correct management of these patients.

Discriminative Utility of Apelin-to-NT-Pro-Brain Natriuretic Peptide Ratio for Heart Failure with Preserved Ejection Fraction among Type 2 Diabetes Mellitus Patients

BACKGROUND

Apelin is a regulatory vasoactive peptide, which plays a pivotal role in adverse cardiac remodeling and heart failure (HF) with reduced ejection fraction. The purpose of the study was to investigate whether serum levels of apelin is associated with HF with preserved election fraction (HFpEF) in patients with T2DM.

METHODS

The study retrospectively involved 101 T2DM patients aged 41 to 62 years (48 patients with HFpEF and 28 non-HFpEF patients). The healthy control group consisted of 25 individuals with matched age and sex. Data collection included demographic and anthropometric information, hemodynamic performances and biomarkers of the disease. Transthoracic B-mode echocardiography, Doppler and TDI were performed at baseline. Serum levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) and apelin were measured by ELISA in all patients at the study entry.

RESULTS

Unadjusted multivariate logistic model yielded the only apelin to NT-proBNP ratio (OR = 1.44; p = 0.001), BMI > 34 кг/м2 (OR = 1.07; p = 0.036), NT-proBNP > 458 pmol/mL (OR = 1.17; p = 0.042), LAVI > 34 mL/m2 (OR = 1.06; p = 0.042) and E/e' > 11 (OR = 1.04; p = 0.044) remained to be strong predictors for HFpEF. After obesity adjustment, multivariate logistic regression showed that the apelin to NT-proBNP ratio < 0.82 × 10-2 units remained sole independent predictor for HFpEF (OR = 1.44; 95% CI: 1.18-2.77; p = 0.001) HFpEF in T2DM patients. In conclusion, we found that apelin to NT-proBNP ratio < 0.82 × 10-2 units better predicted HFpEF in T2DM patients than apelin and NT-proBNP alone. This finding could open new approach for CV risk stratification of T2DM at higher risk of HF.

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.

The Prognostic Impact of Estimated Creatinine Clearance by Bioelectrical Impedance Analysis in Heart Failure: Comparison of Different eGFR Formulas

The estimation of glomerular filtration rate (eGFR) provides prognostic information in patients with heart failure (HF). Bioelectrical impedance analysis may calculate eGFR (Donadio formula). The aim of this study was to evaluate the impact of the Donadio formula in predicting all-cause mortality in patients with HF as compared to Cockroft-Gault, MDRD-4 (Modification of Diet in renal Disease Study), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas. Four-hundred thirty-six subjects with HF (52% men; mean age 75 ± 11 years; 42% acute HF) were enrolled. Ninety-two patients (21%) died during the follow-up (median 463 days, IQR 287-669). The area under the receiver operator characteristic curve for eGFR, as estimated by Cockroft-Gault formula (AUC = 0.75), was significantly higher than those derived from Donadio (AUC = 0.72), MDRD-4 (AUC = 0.68), and CKD-EPI (AUC = 0.71) formulas. At multivariate analysis, all eGFR formulas were independent predictors of death; 1 mL/min/1.73 m2 increase in eGFR-as measured by Cockroft-Gault, Donadio, MDRD-4, and CKD-EPI formulas-provided a 2.6%, 1.5%, 1.2%, and 1.6% increase, respectively, in mortality rate. Conclusions. eGFR, as calculated with the Donadio formula, was an independent predictor of mortality in patients with HF as well as the measurements derived from MDRD4 and CKD-EPI formulas, but less accurate than Cockroft-Gault.

The use of bioelectrical impedance vector analysis for a nutritional evaluation of older adults in the community

INTRODUCTION

The body composition of an older adult person is characterized by an increase in body fat, as well as by a reduction in both muscle mass and total body water. The bioelectrical impedance vector analysis (BIVA) overcomes the limits imposed by bioelectrical impedance, since it only requires the resistance (R) and reactance (Xc) values, standardized by the individual's height, which makes the method more individualized and accurate. The aim of this study was to evaluate the body composition using the BIVA of the community-living older adults, with regard to sex and body mass index (BMI) classification, and compare the results with the reference population.

METHODS

Cross-sectional study with the community-living older adults of both sexes. Bioimpedance was carried out and the R and Xc data analyzed, based on height, and plotted on RXc graphs.

RESULTS

One hundred and forty-four older adults (n = 33 men; n = 111 women; mean age of 80.2 ± 9.2 years) participated in the study. Low weight (<23 kg/m²) was the most prevalent in BMI classification. The older adult women presented a higher average BMI, body fat percentage and R/Height values, while the older adult men presented a higher average for fat-free mass and the phase angle (p < 0.05). The older adult, regardless of their BMI, located in the right quadrant, indicated cachexia; those with low weight were dehydrated, and those with overweight (BMI ≥ 28 kg/m²) presented hyperhydration.

CONCLUSION

The majority of the older adults with normal weight or overweight has impedance vectors indicating loss of muscle mass and water imbalance (dehydration or hyperhydration).

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.

Phase Angle Is an Independent Predictor of 6-Month Mortality in Patients With Decompensated Cirrhosis: A Prospective Cohort Study

BACKGROUND

This study aimed to evaluate the nutrition status through phase angle (PA) and its association with mortality in patients with decompensated cirrhosis.

METHODS

A prospective cohort study was performed with hospitalized decompensated cirrhotic patients. Nutrition status was assessed by PA, bioelectrical impedance vector analysis (BIVA), and Subjective Global Assessment (SGA) within 72 hours of hospital admission. The best PA cutoff point for malnutrition diagnosis was determined by ROC curve analysis, considering the SGA as the reference standard. Predictors of 6-month mortality were identified using Cox proportional hazards models, adjusted for Child-Pugh and MELD scores, and hepatocellular carcinoma.

RESULTS

This study included 97 patients, 63% male (n = 61), with a mean age of 60.1 ± 10.3 years. The median follow-up time of patients was 11.2 months (IQR, 2.4-21). Overall mortality was 58.8% (n = 57) and 6-month mortality was 35.1% (n = 34). Nutrition assessment according to BIVA indicated a risk for cachexia and normal hydration. Patients with values of PA ≤5.52° were considered malnourished. Malnourished patients according to PA (58.8%, n = 57) had a higher risk of 6-month mortality (HR = 3.44; 95% CI, 1.51-7.84; P = .003), and each increase of 1° in PA values was associated with a reduction of 53% in 6-month mortality risk.

CONCLUSIONS

The PA is an independent predictor of 6-month mortality in patients with decompensated cirrhosis. Therefore, PA may be useful to assess the nutrition status and identify patients at the highest risk of mortality in clinical practice.

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.

Nocturnal thoracic volume overload and post-discharge outcomes in patients hospitalized for acute heart failure

Aims

Volume overload and perturbations of pulsatile haemodynamics may precipitate acute heart failure (AHF). Nocturnal thoracic volume overload due to rostral fluid shift during recumbency undetected by daytime measures may impact nighttime haemodynamics and post‐discharge outcomes.

Methods and results

A total of 63 patients (median 60 years, 79.4% men, and left ventricular ejection fraction 29.4%) hospitalized for AHF were enrolled. Once clinical euvolaemia was achieved, noninvasive pulsatile haemodynamics were assessed during daytime followed by circadian monitoring (6 p.m. to 5 a.m.) of thoracic fluid content and thoracic fluid content index (TFCi) using impedance cardiography, normalized electromechanical activation time ratio (EMAT%) using acoustic cardiography, and mean blood pressure using ambulatory blood pressure monitoring before discharge. The primary endpoints were composited of the first hospitalization for heart failure and death from any cause. Patients were also followed for the repeated heart failure hospitalizations. During a median follow‐up duration of 16 months, 33 patients encountered primary composite endpoints (52.4%), and there were 42 hospitalizations developed among 25 patients. An overnight increase in TFCi along with persistently prolonged EMAT% and low mean blood pressure was observed in the eventful group. Overnight increase in TFCi (ΔTFCi, the difference between the measures at 4 a.m. and 6 p.m.) was an independent predictor of primary composite events (hazard ratio and 95% confidence interval: 1.58, 1.07–2.33; P = 0.022) and recurrent composite events (2.22, 1.51–3.26; P < 0.001), after adjusting for potential confounding factors. A high ΔTFCi (≥0.5/kΩ/m²) significantly correlated with higher post‐discharge events (hazard ratio 6.25; 95% confidence interval 2.30–16.96; P < 0.001) in comparison with a low ΔTFCi (<0.5/kΩ/m²). ΔTFCi was significantly associated with EMAT%, estimated glomerular filtration rate, and left ventricular ejection fraction, but not with parameters of pulsatile haemodynamics.

Conclusions

Nocturnal thoracic volume overload in AHF before discharge, indicating the presence of residual volume overload unidentified by daytime measures, may predict post‐discharge outcomes.

Relationship among Activities of Daily Living, Nutritional Status, and 90 Day Readmission in Elderly Patients with Heart Failure

Purpose: This investigation aimed to examine the relationship among activities of daily living (ADL), nutritional status and 90-day hospital readmission in elderly heart failure (HF) patients. Methods: Participants were selected from 634 HF patients consecutively hospitalized at one institution. We investigated patient characteristics, ADL (motor and cognitive items of Functional Independence Measure (FIM)) and nutritional status (Geriatric Nutritional Risk Index (GNRI)). Data were analyzed using unpaired t-test, χ² test, Cox proportional hazard model, and Kaplan-Meier method. Results: The 169 participants that met inclusion criteria were divided into two groups based on hospital readmission within 90 days of discharge. Body mass index (BMI) (p = 0.03), hemoglobin (p = 0.047), GNRI (p = 0.02) and motor-FIM (p = 0.007) were significantly different between the readmission (n = 31) and non-readmission (n = 138) groups. After Cox proportional hazard model analysis, GNRI (HR: 0.96; p = 0.048) and motor-FIM (HR: 0.97; p = 0.03) scores remained statistically significant. Participants were then classified into four groups based on a previous study’s cut-off values of prognosis for GNRI and motor-FIM. Readmission avoidance rate was significantly lower (p = 0.002) in the group with GNRI <92 and motor FIM <75. Conclusions: This study showed that motor-FIM and GNRI scores for hospitalized elderly HF patients were predictors of readmission within 90 days of discharge.

Combined analysis of miRNA-181a with phase angle derived from bioelectrical impedance predicts radiotherapy-induced changes in body composition and survival of male patients with head and neck cancer

BACKGROUND

Nutritional deficits developing as an effect of applied radiotherapy (RTH) negatively affect patients' quality of life, survival, and therapy outcomes. We demonstrated novel approach to prediction of RTH-induced changes in body composition of patients with head and neck cancer using phase angle (PA) derived from bioelectrical impedance in combination with miRNA-181a expression.

RESULTS

Patients with simultaneous presence of low PA and high miRNA expression were at a significantly higher risk of decreasing the fat-free mass index (FFMI) <14.9 kg/m² (odds ratio [OR] = 5.14; P = .02), FFM < 44.7 kg (OR = 6.20; P = .04), and lean mass (OR = 10.0; P = .04) during the therapy period. Receiver operating curve analysis allowed to predict changes in FFMI, lean mass, and FFM with area under the curve calculation over 0.700. The simultaneous presence of high miRNA and low PA negatively affected patients' survival (OR = 5.12; P = .02).

CONCLUSION

Evaluation of PA in combination with miRNA demonstrates higher diagnostic accuracy and predictive value for detecting RTH-induced changes in body composition of patients with cancer.

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.