Real World Use of Hypertonic Saline in Refractory Acute Decompensated Heart Failure: A U.S. Center's Experience

Basal natriuresis as a predictor of diuretic resistance and clinical evolution in acute heart failure

BACKGROUND

Some clinical guidelines recommend serial measurement of natriuresis to detect diuretic resistance (DR) in acute heart failure (AHF) patients, but it adds complexity to the management.

OBJECTIVES

To correlate a single measurement of basal natriuresis (BN) on admission with the development of DR and clinical evolution in AHF hospitalized patients.

METHODS

Prospective and multicenter study included AHF hospitalized patients, without shock or creatinine >2.5mg%. Patients received 40mg of intravenous furosemide on admission, then BN was measured, and diuretic treatment was guided by protocol. BN was considered low if <70 meq/L. DR was defined as the need of furosemide >240mg/day, tubular blockade (TB), hypertonic saline solution (HSS) or renal replacement therapy (RRT). In-hospital cardiovascular (CV) mortality, CV mortality and AHF readmissions at 60-day post-discharge were evaluated.

RESULTS

157 patients were included. BN was low in 22%. DR was development in 19% (12.7% furosemide >240mg/day, 8% TB, 4% RRT). Low NB was associated with DR (44% vs 12%; p 0.0001), persistence of congestion (26.5% vs 11.4%; p 0.05), furosemide >240 mg/day (29% vs 8%; p 0.003), higher cumulative furosemide dose at 72 hours (220 vs 160mg; p 0.0001), TB (20.6 vs 4.9%; p 0.008), RRT (11.8 vs 1.6%; p 0.02), worsening of AHF (27% vs 9%; p 0.01), inotropes use (21% vs 7%; p 0.48), respiratory assistance (12% vs 2%; p 0.02) and a higher in-hospital CV mortality (12% vs 4%; p 0.1). No association was demonstrated with post-discharge endpoints.

CONCLUSIONS

In AHF patients, low BN was associated with DR, persistent congestion, need for aggressive decongestion strategies, and worse in-hospital evolution.

Efficacy and safety of hypertonic saline therapy in ambulatory patients with heart failure: The SALT-HF trial

AIMS

Combination of hypertonic saline solution (HSS) with intravenous loop diuretics has been suggested to improve diuretic response in patients hospitalized for heart failure (HF). The efficacy and safety of this approach in the ambulatory setting remain unexplored.

METHODS AND RESULTS

In this multicentre, double-blind, randomized study, we allocated ambulatory patients with worsening heart failure (WHF) to a 1-h infusion of intravenous furosemide (ivFurosemide)-HSS versus ivFurosemide. The primary endpoint was the volume of diuresis at 3 h. Secondary endpoints included 3-h natriuresis and weight variation, 7-day congestion data, kidney function and electrolytes, and 30-day clinical events. Overall, 167 participants (median age: 81 years, 30.5% female) were randomized across 13 sites between December 2020 and March 2023. There were no differences in 3-h diuresis between treatments (ivFurosemide-HSS: 1099 ml vs. ivFurosemide: 1103 ml, p = 0.963), 3-h natriuresis (∆ +2.642 mEq/L, p = 0.559), or 3-h weight (∆ +0.012 kg, p = 0.920). Patients in the ivFurosemide-HSS arm experienced significant weight decrease at 7 days (Δ -0.586 kg, p = 0.048). There were no between-treatment differences in clinical congestion score, biomarkers, inferior vena cava diameter, or the presence of lung ultrasound B-lines. At 30 days, 26.5% of the patients in the ivFurosemide-HSS group versus 33.3% in the ivFurosemide group experienced WHF (hazard ratio 0.76, p = 0.330). The incidence of death from any cause or HF hospitalization was 6% of patients in the ivFurosemide-HSS group and 8.3% of patients in the ivFurosemide group (hazard ratio 0.69, p = 0.521). The incidence of worsening kidney function or metabolic derangements was not significantly different in the two arms.

CONCLUSIONS

A single infusion of ivFurosemide-HSS did not improve 3-h diuresis or congestion parameters in patients with ambulatory WHF. This therapy showed an appropriate safety profile.

Evaluation and Management of Hyponatremia in Heart Failure

PURPOSE OF REVIEW

To provide a contemporary overview of the pathophysiology, evaluation, and treatment of hyponatremia in heart failure (HF).

RECENT FINDINGS

Potassium and magnesium losses due to poor nutritional intake and treatment with diuretics cause an intracellular sodium shift in HF that may contribute to hyponatremia. Impaired renal blood flow leading to a lower glomerular filtration rate and increased proximal tubular reabsorption lead to an impaired tubular flux through diluting distal segments of the nephron, compromising electrolyte-free water excretion. Hyponatremia in HF is typically a condition of impaired water excretion by the kidneys on a background of potassium and magnesium depletion. While those cations can and should be easily repleted, further treatment should mainly focus on improving the underlying HF and hemodynamics, while addressing congestion. For decongestive treatment, proximally acting diuretics such as sodium-glucose co-transporter-2 inhibitors, acetazolamide, and loop diuretics are the preferred options.

Design and baseline characteristics of SALT-HF trial: hypertonic saline therapy in ambulatory heart failure

AIMS

Hypertonic saline solution (HSS) plus intravenous (IV) loop diuretic appears to enhance the diuretic response in patients hospitalized for heart failure (HF). The efficacy and safety of this therapy in the ambulatory setting have not been evaluated. We aimed to describe the design and baseline characteristics of the SALT-HF trial participants.

METHODS AND RESULTS

'Efficacy of Saline Hypertonic Therapy in Ambulatory Patients with HF' (SALT-HF) trial was a multicenter, double-blinded, and randomized study involving ambulatory patients who experienced worsening heart failure (WHF) without criteria for hospitalization. Enrolled patients had to present at least two signs of volume overload, use ≥ 80 mg of oral furosemide daily, and have elevated natriuretic peptides. Patients were randomized 1:1 to treatment with a 1-h infusion of IV furosemide plus HSS (2.6-3.4% NaCl depending on plasmatic sodium levels) versus a 1-h infusion of IV furosemide at the same dose (125-250 mg, depending on basal loop diuretic dose). Clinical, laboratory, and imaging parameters were collected at baseline and after 7 days, and a telephone visit was planned after 30 days. The primary endpoint was 3-h diuresis after treatment started. Secondary endpoints included (a) 7-day changes in congestion data, (b) 7-day changes in kidney function and electrolytes, (c) 30-day clinical events (need of IV diuretic, HF hospitalization, cardiovascular mortality, all-cause mortality or HF-hospitalization).

RESULTS

A total of 167 participants [median age, 81 years; interquartile range (IQR), 73-87, 30.5% females] were randomized across 13 sites between December 2020 and March 2023. Half of the participants (n = 82) had an ejection fraction >50%. Most patients showed a high burden of comorbidities, with a median Charlson index of 3 (IQR: 2-4). Common co-morbidities included diabetes mellitus (41%, n = 69), atrial fibrillation (80%, n = 134), and chronic kidney disease (64%, n = 107). Patients exhibited a poor functional NYHA class (69% presenting NYHA III) and several signs of congestion. The mean composite congestion score was 4.3 (standard deviation: 1.7). Ninety per cent of the patients (n = 151) presented oedema and jugular engorgement, and 71% (n = 118) showed lung B lines assessed by ultrasound. Median inferior vena cava diameter was 23 mm, (IQR: 21-25), and plasmatic levels of N-terminal-pro-B-type natriuretic peptide (NTproBNP) and antigen carbohydrate 125 (CA125) were increased (median NT-proBNP 4969 pg/mL, IQR: 2508-9328; median CA125 46 U/L, IQR: 20-114).

CONCLUSIONS

SALT-HF trial randomized 167 ambulatory patients with WHF and will determine whether an infusion of hypertonic saline therapy plus furosemide increases diuresis and improves decongestion compared to equivalent furosemide administration alone.

Combinational Diuretics in Heart Failure

PURPOSE OF REVIEW

Diuretics are the cornerstone therapy for acute heart failure (HF) and congestion. Patients chronically exposed to loop diuretics may develop diuretic resistance as a consequence of nephron remodelling, and the combination of diuretics will be necessary to improve diuretic response and achieve decongestion. This review integrates data from recent research and offers a practical approach to current pharmacologic therapies to manage congestion in HF with a focus on combinational therapy.

RECENT FINDINGS

Until recently, combined diuretic treatment was based on observational studies and expert opinion. Recent evidence from clinical trials has shown that combined diuretic treatment can be started earlier without escalating the doses of loop diuretics with an adequate safety profile. Diuretic combination is a promising strategy for overcoming diuretic resistance in HF. Further studies aiming to get more insights into the pathophysiology of diuretic resistance and large clinical trials confirming the safety and efficacy over standard diuretics regimens are warranted.

Renal Sodium Avidity in Heart Failure

BACKGROUND

Increased renal sodium avidity is a hallmark feature of the heart failure syndrome.

SUMMARY

Increased renal sodium avidity refers to the inability of the kidneys to elicit potent natriuresis in response to sodium loading. This eventually causes congestion, which is a major contributor to hospital admissions and mortality in heart failure.

KEY MESSAGES

Important novel concepts such as the renal tamponade hypothesis, accelerated nephron loss, and the role of hypochloremia, the sympathetic nervous system, inflammation, the lymphatic system, and interstitial sodium buffers are involved in the pathophysiology of renal sodium avidity. A good understanding of these concepts is crucially important with respect to treatment recommendations regarding dietary sodium restriction, fluid restriction, rapid up-titration of guideline-directed medical therapies, combination diuretic therapy, natriuresis-guided diuretic therapy, use of hypertonic saline, and ultrafiltration.

Diuretic Treatment in Patients with Heart Failure: Current Evidence and Future Directions-Part II: Combination Therapy

PURPOSE OF REVIEW

Fluid retention or congestion is a major cause of symptoms, poor quality of life, and adverse outcome in patients with heart failure (HF). Despite advances in disease-modifying therapy, the mainstay of treatment for congestion-loop diuretics-has remained largely unchanged for 50 years. In these two articles (part I: loop diuretics and part II: combination therapy), we will review the history of diuretic treatment and current trial evidence for different diuretic strategies and explore potential future directions of research.

RECENT FINDINGS

We will assess recent trials, including DOSE, TRANSFORM, ADVOR, CLOROTIC, OSPREY-AHF, and PUSH-AHF, and assess how these may influence current practice and future research. There are few data on which to base diuretic therapy in clinical practice. The most robust evidence is for high-dose loop diuretic treatment over low-dose treatment for patients admitted to hospital with HF, yet this is not reflected in guidelines. There is an urgent need for more and better research on different diuretic strategies in patients with HF.

Dietary sodium and fluid intake in heart failure. A clinical consensus statement of the Heart Failure Association of the ESC

Sodium and fluid restriction has traditionally been advocated in patients with heart failure (HF) due to their sodium and water avid state. However, most evidence regarding the altered sodium handling, fluid homeostasis and congestion-related signs and symptoms in patients with HF originates from untreated patient cohorts and physiological investigations. Recent data challenge the beneficial role of dietary sodium and fluid restriction in HF. Consequently, the European Society of Cardiology HF guidelines have gradually downgraded these recommendations over time, now advising for the limitation of salt intake to no more than 5 g/day in patients with HF, while contemplating fluid restriction of 1.5-2 L/day only in selected patients. Therefore, the objective of this clinical consensus statement is to provide advice on fluid and sodium intake in patients with acute and chronic HF, based on contemporary evidence and expert opinion.

Contemporary Decongestive Strategies in Acute Heart Failure

Congestion is the primary driver of hospital admissions in patients with heart failure and the key determinant of their outcome. Although intravenous loop diuretics remain the predominant agents used in the setting of acute heart failure, the therapeutic response is known to be variable, with a significant subset of patients discharged from the hospital with residual hypervolemia. In this context, urinary sodium excretion has gained attention both as a marker of response to loop diuretics and as a marker of prognosis that may be a useful clinical tool to guide therapy. Several decongestive strategies have been explored to improve diuretic responsiveness and removal of excess fluid. Sequential nephron blockade through combination diuretic therapy is one of the most used methods to enhance natriuresis and counter diuretic resistance. In this article, I provide an overview of the contemporary decongestive approaches and discuss the clinical data on the use of add-on diuretic therapy. I also discuss mechanical removal of excess fluid through extracorporeal ultrafiltration with a brief review of the results of landmark studies. Finally, I provide a short overview of the strategies that are currently under investigation and may prove helpful in this setting.

[Consensus recommendations on the diagnosis and treatment of hyponatremia from the Austrian Society for Nephrology 2024]

Hyponatremia is a disorder of water homeostasis. Water balance is maintained by the collaboration of renal function and cerebral structures, which regulate thirst mechanisms and secretion of the antidiuretic hormone. Measurement of serum-osmolality, urine osmolality and urine-sodium concentration help to diagnose the different reasons for hyponatremia. Hyponatremia induces cerebral edema and might lead to severe neurological symptoms, which need acute therapy. Also, mild forms of hyponatremia should be treated causally, or at least symptomatically. An inadequate fast increase of the serum sodium level should be avoided, because it raises the risk of cerebral osmotic demyelination. Basic pathophysiological knowledge is necessary to identify the different reasons for hyponatremia which need different therapeutic procedures.

Combination Diuretic Therapy to Counter Renal Sodium Avidity in Acute Heart Failure: Trials and Tribulations

In contrast to significant advances in the management of patients with chronic heart failure over the past few years, there has been little change in how patients with acute heart failure are treated. Symptoms and signs of fluid overload are the primary reason for hospitalization of patients who experience acute decompensation of heart failure. Intravenous loop diuretics remain the mainstay of therapy in this patient population, with a significant subset of them showing suboptimal response to these agents leading to incomplete decongestion at the time of discharge. Combination diuretic therapy, that is, using loop diuretics along with an add-on agent, is a widely applied strategy to counter renal sodium avidity through sequential blockade of sodium absorption within renal tubules. The choice of the second diuretic is affected by several factors, including the site of action, the anticipated secondary effects, and the available evidence on their efficacy and safety. While the current guidelines recommend combination diuretic therapy as a viable option to overcome suboptimal response to loop diuretics, it is also acknowledged that this strategy is not supported by strong evidence and remains an area of uncertainty. The recent publication of landmark studies has regenerated the interest in sequential nephron blockade. In this article, we provide an overview of the results of the key studies on combination diuretic therapy in the setting of acute heart failure and discuss their findings primarily with regard to the effect on renal sodium avidity and cardiorenal outcomes.

The added value of hypertonic saline solution to furosemide monotherapy in patients with acute decompensated heart failure: A meta-analysis and trial sequential analysis

We assessed the effects of hypertonic saline solution (HSS) plus furosemide versus furosemide alone in patients with acute decompensated heart failure (ADHF). We searched four electronic databases for randomized controlled trials (RCTs) until June 30, 2022. The quality of evidence (QoE) was assessed using the GRADE approach. All meta-analyses were performed using a random-effects model. A trial sequential analysis (TSA) was also conducted for intermediate and biomarker outcomes. Ten RCTs involving 3013 patients were included. HSS plus furosemide significantly reduced the length of hospital stay (mean difference [MD]: -3.60 days; 95% confidence interval [CI]: -4.56 to -2.64; QoE: moderate), weight (MD: -2.34 kg; 95% CI: -3.15 to -1.53; QoE: moderate), serum creatinine (MD: -0.41 mg/dL; 95% CI: -0.49 to -0.33; QoE: low), and type-B natriuretic peptide (MD: -124.26 pg/mL; 95% CI: -207.97 to -40.54; QoE: low) compared to furosemide alone. HSS plus furosemide significantly increased urine output (MD: 528.57 mL/24 h; 95% CI: 431.90 to 625.23; QoE: moderate), serum Na+ (MD: 6.80 mmol/L; 95% CI: 4.92 to 8.69; QoE: low), and urine Na+ (MD: 54.85 mmol/24 h; 95% CI: 46.31 to 63.38; QoE: moderate) compared to furosemide alone. TSA confirmed the benefit of HSS plus furosemide. Due to the heterogeneity in mortality and heart failure readmission, meta-analysis was not performed. Our study shows that HSS plus furosemide, compared to furosemide alone, improved surrogated outcomes in ADHF patients with low or intermediate QoE. Adequately powered RCTs are still needed to assess the benefit on heart failure readmission and mortality.

Canadian Cardiovascular Society-Canadian Heart Failure Society Focused Clinical Practice Update of Patients With Differing Heart Failure Phenotypes

A number of societies produce heart failure (HF) management guidelines, comprising official recommendations on the basis of recent research discoveries, but their applicability to specific situations encountered in daily practice might be difficult. In this clinical practice update we aim to provide responses to fundamental questions that face health care providers, like appropriate timing for the introduction and optimization of different classes of medication according to specific patient phenotypes, when second-line therapies and valvular interventions should be considered, and management of difficult clinical scenarios such as cardiorenal syndrome and frailty. A consensus-based methodology was used. Approaches to 5 different phenotypes are presented: (1) The wet HF phenotype is the easiest to manage, decongestion being performed alongside introduction of guideline-directed medical therapy (GDMT); (2) The de novo HF phenotype requires the introduction of the 4 pillars of GDMT, personalizing the order on the basis of the individuals' biological and physiological characteristics; (3) The worsening HF phenotype is a marker of poor prognosis, and therefore should motivate optimization of GDMT, start second-line therapies, and/or reevaluate goals of care/advanced HF therapies; (4) The cardiorenal phenotypes require correct volume assessment, because renal function usually improves with decongestion; and (5) The frail HF phenotype require special attention, careful drug titration, and consideration of cardiac rehabilitation programs. In conclusion, specific common HF phenotypes call for a personalized approach to improve adoption of the HF guidelines into clinical practice.

Oral Sodium to Preserve Renal Efficiency in Acute Heart Failure: A Randomized, Placebo-Controlled, Double-Blind Study

BACKGROUND

Evidence for modulating the sodium chloride (NaCl) intake of patients hospitalized with acute heart failure (AHF) is inconclusive. Salt restriction may not benefit; hypertonic saline may aid diuresis.

OBJECTIVE

To compare the safety and efficacy of oral NaCl during intravenous (IV) diuretic therapy in renal function and weight.

METHODS

Seventy hospitalized patients with AHF who were being treated with IV furosemide infusion consented to receive, randomly, 2 grams of oral NaCl or placebo 3 times a day in a double-blind manner during diuresis. Treatment efficacy (bivariate primary endpoints of change in serum creatinine levels and change in weight) was measured at 96 hours, and adverse safety events were tracked for 90 days.

RESULTS

Sixty-five patients (34 NaCl, 31 placebo) were included for analysis after 5 withdrew. A median of 13 grams of NaCl was given compared to placebo. At 96 hours, there was no significant difference between treatment groups with respect to the primary endpoint (P = 0.33); however, the trial was underpowered, and there was greater than expected standard deviation in weight change. The mean change in creatinine levels and weight was 0.15 ± 0.44 mg/dL and 4.6 ± 4.2 kg in the placebo group compared with 0.04 ± 0.40 mg/dL and 4.0 ± 4.3 kg in the NaCl group (P = 0.30 and 0.57, respectively). Across efficacy and safety endpoints, we observed no significant difference between the 2 groups other than changes in serum sodium levels (-2.6 ± 2.7 in the placebo group and -0.3 ± 3.3 mEq/L in the NaCl group; P < 0.001) and in serum blood urea nitrogen levels (11 ± 15 in the placebo group; 3.1 ± 13 mEq/L in the NaCl group; P = 0.025).

CONCLUSIONS

In this single-center study, liberal vs restrictive oral sodium chloride intake strategies did not impact the safety and efficacy of intravenous diuretic therapy in patients with AHF. (ClinicalTrials.gov registration NCT04334668.).

Role of Sodium and Sodium Restriction in Heart Failure

PURPOSE OF REVIEW

Sodium plays an essential role in the regulation of extracellular volume. The current review discusses the physiologic handling of sodium in the body, underscores pathophysiologic alterations in sodium handling in heart failure and assesses the evidence and rational for sodium restriction in heart failure.

RECENT FINDINGS

Recent trials such as the SODIUM-HF trial have failed to demonstrate a benefit of sodium restriction in heart failure. The current review re-evaluates physiologic elements in sodium handling and discusses how the intrinsic renal sodium avidity, which drives the renal propensity towards retaining sodium, differs amongst patients. The sodium intake in heart failure patients is often above the threshold set by guidelines. This review gives an overview of the pathophysiology of sodium retention in heart failure and the rational for sodium restriction and potential of individualizing sodium restriction recommendations based on renal sodium avidity profiles.

Serum Chloride and Heart Failure

Despite significant advances in management, heart failure continues to impose a significant epidemiologic burden with high prevalence and mortality rates. For decades, sodium has been the serum electrolyte most commonly associated with outcomes; however, challenging the conventional paradigm of sodium's influence, recent studies have identified a more prominent role in serum chloride in the pathophysiology of heart failure. More specifically, hypochloremia is associated with neurohumoral activation, diuretic resistance, and a worse prognosis in patients with heart failure. This review examines basic science, translational research, and clinical studies to better characterize the role of chloride in patients with heart failure and additionally discusses potential new therapies targeting chloride homeostasis that may impact the future of heart failure care.

Ultrasound assessment of diaphragmatic dysfunction and its improvement with levosimendan in patients with chronic obstructive pulmonary disease

Diaphragmatic Dysfunction (DD) is a clinical condition in which the diaphragm becomes weak or paralyzed, because of muscle strength reduction. It can be due to muscular issues or loss of proper innervation, but, also, to pulmonary hyperinflation or air trapping, such as in Chronic Obstructive Pulmonary Disease (COPD). DD impacts on COPD induced dyspnea, determining its progressive worsening, but levosimendan, an inodilator better known as Ca2+ sensitizer, may limit this phenomenon and diaphragmatic ultrasound assessment can be useful in monitoring its effect. Here, we show the case of a 77-year-old woman admitted to the Emergency department for acute exacerbation of chronic dyspnea in COPD, related to right ventricular failure and DD, which did not respond to medical therapy and non-invasive mechanical ventilation but did experience a favorable outcome after intravenous administration of levosimendan.

Acute Cardiorenal Syndrome: An Update

The complex dynamic pathophysiological interplay between the heart and kidney causes a vicious cycle of worsening renal and/or cardiovascular function. Acute decompensated heart failure causing worsening renal function defines Type 1 cardiorenal syndrome (CRS). Altered hemodynamics coupled with a multitude of nonhemodynamic factors namely pathological activation of the renin angiotensin aldosterone system and systemic inflammatory pathways mechanistically incite CRS type 1. A multipronged diagnostic approach utilizing laboratory markers, noninvasive and/or invasive modalities must be implemented to enable timely initiation of effective treatment strategies. In this review, we discuss the pathophysiology, diagnosis, and emerging treatment options for CRS type 1.

Etiology and Management of Edema: A Review

The development of peripheral edema can often pose a significant diagnostic and therapeutic challenge for practitioners due to its association with a wide variety of underlying disorders ranging in severity. Updates to the original Starling's principle have provided new mechanistic insights into edema formation. Additionally, contemporary data highlighting the role of hypochloremia in the development of diuretic resistance provide a possible new therapeutic target. This article reviews the pathophysiology of edema formation and discusses implications for treatment.

Impact of Dapagliflozin Treatment on Serum Sodium Concentrations in Acute Heart Failure

INTRODUCTION

The dynamics of serum sodium are important in acute heart failure (AHF), and hyponatremia is associated with a poor prognosis. The effect of sodium-glucose cotransporter type 2 inhibitors (SGLT2i) on serum sodium concentrations in AHF is unknown.

METHODS

In a single-centre, controlled, randomized study, patients were prescribed dapagliflozin in addition to standard treatment during the first 24 h of hospitalization versus standard treatments. The pre-specified outcome was an absolute change in plasma sodium concentrations between randomization (first 24 h after admission) and discharge. The secondary outcomes were an absolute change in serum sodium concentrations within 48 h of randomization and the persistence of hyponatremia.

RESULTS

The sample comprised 285 patients (53% males; average age 73.26 ± 13 years); 140 of these were randomized to the dapagliflozin group. The average ejection fraction was 46 ± 14%; 155 patients (54%) had ischaemic heart failure; and 35% had diabetes mellitus. Median N-terminal pro b-type natriuretic peptide was 4,225 [2,120; 9,105] pg/mL. The average estimated glomerular filtration rate was 53.9 ± 17.2 mL/min. Hospital mortality was 6.7%. At randomization, serum sodium concentrations were 139.8 ± 4.32 mmol/L in the dapagliflozin group versus 140.85 ± 4.04 mmol/L in the control group; p = 0.048. 48 h later, there was an increase in serum sodium in the dapagliflozin group (2 [-2; 4] mmol/L), as compared to the control group (-1 [-3.75; 2]); p < 0.001. This was accompanied by equilibration of the sodium levels between the groups (141.08 ± 4.08 mmol/L in the dapagliflozin group vs. 140.05 ± 4.82 mmol/L in the control group; p = 0.096). At the time of discharge, there was no difference in serum sodium concentrations (140.98 ± 4.77 mmol/L vs. 139.86 ± 4.45 mmol/L; p = 0.082). The increase in serum sodium concentrations during the period of observation [randomization; discharge] was small but statistically significant in the dapagliflozin group (1 [-3; 3.75] mmol/L vs. -2 [-4.5; 2] mmol/L; p = 0.015). Of 36 patients (21 in the dapagliflozin group and 15 in the control group) with baseline hyponatraemia, this persisted in 6 (16.6%) in the dapagliflozin group and in 11 (73.3%) in the control group (p = 0.008).

CONCLUSION

The use of dapagliflozin in AHF is associated with a tendency to the increase in serum sodium concentrations and lesser persistence of hyponatremia. This effect occurred within the first 48 h and persisted until discharge. The impact of dapagliflozin on serum sodium was more pronounced in patients with hyponatremia at randomization.

Acute Cardiorenal Syndrome: Epidemiology, Pathophysiology, Assessment, and Treatment

Acute cardiorenal syndrome (CRS) is often observed in patients with acute kidney injury (AKI) in the cardiac intensive care unit and is reported to be associated with poor prognosis. Volume disorder or re-distribution, renin-angiotensin-aldosterone system activation, and neurohormonal and sympathetic nervous system activation have been suggested to be related to the occurrence of acute CRS. There is a lack of biomarkers that can identify changes in renal function in patients with acute CRS. Evidence-based medications are limited in the management of acute CRS in AKI. Therefore, we reviewed the epidemiology, pathophysiology, clinical assessment, and treatment of acute CRS in AKI.

Management of Hyponatremia in Heart Failure: Practical Considerations

Hyponatremia is commonly encountered in the setting of heart failure, especially in decompensated, fluid-overloaded patients. The pathophysiology of hyponatremia in patients with heart failure is complex, including numerous mechanisms: increased activity of the sympathetic nervous system and the renin-angiotensin-aldosterone system, high levels of arginine vasopressin and diuretic use. Symptoms are usually mild but hyponatremic encephalopathy can occur if there is an acute decrease in serum sodium levels. It is crucial to differentiate between dilutional hyponatremia, where free water excretion should be promoted, and depletional hyponatremia, where administration of saline is needed. An inappropriate correction of hyponatremia may lead to osmotic demyelination syndrome which can cause severe neurological symptoms. Treatment options for hyponatremia in heart failure, such as water restriction or the use of hypertonic saline with loop diuretics, have limited efficacy. The aim of this review is to summarize the principal mechanisms involved in the occurrence of hyponatremia, to present the main guidelines for the treatment of hyponatremia, and to collect and analyze data from studies which target new treatment options, such as vaptans.

Continuous Renal Replacement Therapy for Hypertension Complicated by Refractory Heart Failure: An Analysis of Safety and Nursing Highlights

Objective

This research is aimed at analyzing the safety profile and nursing highlights of continuous renal replacement therapy (CRRT) for hypertension (HT) complicated by refractory heart failure (RHF).

Methods

Sixty-six HT + RHF patients admitted between March 2018 and December 2021 were enrolled and assigned to two groups: a CRRT group with 33 cases treated with CRRT and a control group with 33 cases intervened by routine treatment. The therapeutic effect and alterations of cardiac function (CF) indexes were observed in both cohorts. Besides, statistics were made in terms of serum B-type natriuretic peptide (BNP), C-reactive protein (CRP) and mean arterial pressure (MAP) concentrations, time of asthma relief, heart rate recovery (HRR), edema resolution, and hospitalization, as well as incidence of adverse reactions (ARs). Finally, pre- and posttreatment psychological quality and pain of both cohorts of subjects were assessed using the self-rating anxiety and depression scale (SAS and SDS) and visual analogue scale (VAS), respectively.

Results

CRRT group exhibited higher overall response rate and better CF than control group (P < 0.05), with lower BNP, CRP, and MAP levels, and shorter time of asthma relief, HRR, edema resolution, and hospitalization (P < 0.05); the incidence of ARs was similar (P > 0.05); for both groups, the scores of SAS, SDS, and VAS reduced statistically after treatment (P < 0.05).

Conclusion

CRRT can effectively improve the therapeutic effect and CF of patients with HT complicated by RHF, to protect the health and safety of patients.

PoCUS in nephrology: a new tool to improve our diagnostic skills

Point-of-Care Ultrasonography (PoCUS) aims to include a fifth pillar (insonation) in the classical physical examination in order to obtain images to answer specific questions by the clinician at the patient's bedside, allowing rapid identification of structural or functional abnormalities, enabling more accurate volume assessment and supporting diagnosis, as well as guiding procedures. In recent years, PoCUS has started becoming a valuable tool in day-to-day clinical practice, adopted by healthcare professionals from various medical specialties, never replacing physical examination but improving patient and medical care and experience. Renal patients represent a wide range of diseases, which lends PoCUS a special role as a valuable tool in different scenarios, not only for volume-related information but also for the assessment of a wide range of acute and chronic conditions, enhancing the sensitivity of conventional physical examination in nephrology. PoCUS in the hands of a nephrologist is a precision medicine tool.

Mechanistic Insights in Cardiorenal Syndrome

Mechanistic Insights in Cardiorenal SyndromeLo and Rangaswami review the pathophysiology and management of cardiorenal syndrome, with a focus on decongestion, interpretation of kidney function, and implementation of guideline directed medical therapies.

Administration of 3% Sodium Chloride and Local Infusion Reactions

Three-percent sodium chloride (3% NaCl) is a hyperosmolar agent used to treat hyponatremic encephalopathy or other cases of increased intracranial pressure. A barrier to the use of 3% NaCl is the perceived risk of local infusion reactions when administered through a peripheral vein. We sought to evaluate reports of local infusion reactions associated with 3% NaCl over a 10-year period throughout a large healthcare system. A query was conducted through the Risk Master database to determine if there were any local infusion reactions associated with peripheral 3% NaCl administration throughout the entire UPMC health system, which consists of 40 hospitals with 8400 licensed beds, over a 10-year time period from 14 May 2010 to 14 May 2020. Search terms included infiltrations, extravasations, phlebitis, IV site issues, and IV solutions. There were 23,714 non-chemotherapeutic and non-contrast-associated intravenous events, of which 4678 (19.7%) were at UPMC Children’s Hospital. A total of 2306 patients received 3% NaCl, of whom 836 (35.8%) were at UPMC Children’s Hospital. There were no reported local infusion reactions with 3% NaCl. There were no reported local infusion reaction events associated with 3% NaCl in a large healthcare system over a 10-year period. This suggests that 3% NaCl can be safely administered through a peripheral IV or central venous catheter.

Multimodal Strategies for the Diagnosis and Management of Refractory Congestion. An Integrated Cardiorenal Approach

Refractory congestion is common in acute and chronic heart failure, and it significantly impacts functional class, renal function, hospital admissions, and survival. In this paper, the pathophysiological mechanisms involved in cardiorenal syndrome and the interplay between heart failure and chronic kidney disease are reviewed. Although the physical exam remains key in identifying congestion, new tools such as biomarkers or lung, vascular, and renal ultrasound are currently being used to detect subclinical forms and can potentially impact its management. Thus, an integrated multimodal diagnostic algorithm is proposed. There are several strategies for treating congestion, although data on their efficacy are scarce and have not been validated. Herein, we review the optimal use and monitorization of different diuretic types, administration route, dose titration using urinary volume and natriuresis, and a sequential diuretic scheme to achieve a multitargeted nephron blockade, common adverse events, and how to manage them. In addition, we discuss alternative strategies such as subcutaneous furosemide, hypertonic saline, and albumin infusions and the available evidence of their role in congestion management. We also discuss the use of extracorporeal therapies, such as ultrafiltration, peritoneal dialysis, or conventional hemodialysis, in patients with normal or impaired renal function. This review results from a multidisciplinary view involving both nephrologists and cardiologists.

Fluid and Salt Balance and the Role of Nutrition in Heart Failure

The main challenges in heart failure (HF) treatment are to manage patients with refractory acute decompensated HF and to stabilize the clinical status of a patient with chronic heart failure. Beyond the use of medications targeted in the inhibition of the neurohormonal system, the balance of salt and fluid plays an important role in the maintenance of clinical compensation in respect of renal function. In the case of heart failure, a debate of opinion exists on salt restriction. Restricted dietary sodium might lead to worse outcomes in heart failure patients due to the activation of the neurohormonal system and malnutrition. On the contrary, positive sodium balance is the primary driver of water retention and, ultimately, volume overload in acute HF. Some recent studies reported associations of decreased salt consumption with higher readmission rates and increased mortality. Thus, the usefulness of salt restriction in heart failure management remains debated. The use of individualized nutritional support, compared with standard hospital food, was effective in reducing these risks, particularly in the group of patients at high nutritional risk.

Classic and Novel Mechanisms of Diuretic Resistance in Cardiorenal Syndrome

Despite the incompletely understood multiple etiologies and underlying mechanisms, cardiorenal syndrome is characterized by decreased glomerular filtration and sodium avidity. The underlying level of renal sodium avidity is of primary importance in driving a congested heart failure phenotype and ultimately determining the response to diuretic therapy. Historically, mechanisms of kidney sodium avidity and resultant diuretic resistance were primarily extrapolated to cardiorenal syndrome from non-heart failure populations. Yet, the mechanisms appear to differ between these populations. Recent literature in acute decompensated heart failure has refuted several classically accepted diuretic resistance mechanisms and reshaped how we conceptualize diuretic resistance mechanisms in cardiorenal syndrome. Herein, we propose an anatomically based categorization of diuretic resistance mechanisms to establish the relative importance of specific transporters and translate findings toward therapeutic strategies. Within this categorical structure, we discuss classic and novel mechanisms of diuretic resistance.

2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: Developed by the Task Force for the diagnosis and treatment of acute and chronic heart failure of the European Society of Cardiology (ESC). With the special contribution of the Heart Failure Association (HFA) of the ESC

Document Reviewers: Rudolf A. de Boer (CPG Review Coordinator) (Netherlands), P. Christian Schulze (CPG Review Coordinator) (Germany), Magdy Abdelhamid (Egypt), Victor Aboyans (France), Stamatis Adamopoulos (Greece), Stefan D. Anker (Germany), Elena Arbelo (Spain), Riccardo Asteggiano (Italy), Johann Bauersachs (Germany), Antoni Bayes-Genis (Spain), Michael A. Borger (Germany), Werner Budts (Belgium), Maja Cikes (Croatia), Kevin Damman (Netherlands), Victoria Delgado (Netherlands), Paul Dendale (Belgium), Polychronis Dilaveris (Greece), Heinz Drexel (Austria), Justin Ezekowitz (Canada), Volkmar Falk (Germany), Laurent Fauchier (France), Gerasimos Filippatos (Greece), Alan Fraser (United Kingdom), Norbert Frey (Germany), Chris P. Gale (United Kingdom), Finn Gustafsson (Denmark), Julie Harris (United Kingdom), Bernard Iung (France), Stefan Janssens (Belgium), Mariell Jessup (United States of America), Aleksandra Konradi (Russia), Dipak Kotecha (United Kingdom), Ekaterini Lambrinou (Cyprus), Patrizio Lancellotti (Belgium), Ulf Landmesser (Germany), Christophe Leclercq (France), Basil S. Lewis (Israel), Francisco Leyva (United Kingdom), AleVs Linhart (Czech Republic), Maja-Lisa Løchen (Norway), Lars H. Lund (Sweden), Donna Mancini (United States of America), Josep Masip (Spain), Davor Milicic (Croatia), Christian Mueller (Switzerland), Holger Nef (Germany), Jens-Cosedis Nielsen (Denmark), Lis Neubeck (United Kingdom), Michel Noutsias (Germany), Steffen E. Petersen (United Kingdom), Anna Sonia Petronio (Italy), Piotr Ponikowski (Poland), Eva Prescott (Denmark), Amina Rakisheva (Kazakhstan), Dimitrios J. Richter (Greece), Evgeny Schlyakhto (Russia), Petar Seferovic (Serbia), Michele Senni (Italy), Marta Sitges (Spain), Miguel Sousa-Uva (Portugal), Carlo G. Tocchetti (Italy), Rhian M. Touyz (United Kingdom), Carsten Tschoepe (Germany), Johannes Waltenberger (Germany/Switzerland) All experts involved in the development of these guidelines have submitted declarations of interest. These have been compiled in a report and published in a supplementary document simultaneously to the guidelines. The report is also available on the ESC website www.escardio.org/guidelines For the Supplementary Data which include background information and detailed discussion of the data that have provided the basis for the guidelines see European Heart Journal online.

Medical management of acute heart failure

Despite recent advances in the treatment of chronic heart failure, therapeutic options for acute heart failure (AHF) remain limited. AHF admissions are associated with significant multi-organ dysfunction, especially worsening renal failure, which results in significant morbidity and mortality. There are several aspects of AHF management: diagnosis, decongestion, vasoactive therapy, goal-directed medical therapy initiation and safe transition of care. Effective diagnosis and prognostication could be very helpful in an acute setting and rely upon biomarker evaluation with noninvasive assessment of fluid status. Decongestive strategies could be tailored to include pharmaceutical options along with consideration of utilizing ultrafiltration for refractory hypervolemia. Vasoactive agents to augment cardiac function have been evaluated in patients with AHF but have shown to only have limited efficacy. Post stabilization, initiation of quadruple goal-directed medical therapy—angiotensin receptor-neprilysin inhibitors, mineral receptor antagonists, sodium glucose type 2 (SGLT-2) inhibitors, and beta blockers—to prevent myocardial remodeling is being advocated as a standard of care. Safe transition of care is needed prior to discharge to prevent heart failure rehospitalization and mortality. Post-discharge close ambulatory monitoring (including remote hemodynamic monitoring), virtual visits, and rehabilitation are some of the strategies to consider. We hereby review the contemporary approach in AHF diagnosis and management.

Administration of Subcutaneous Furosemide in Elastomeric Pump vs. Oral Solution for the Treatment of Diuretic Refractory Congestion

INTRODUCTION

The most common symptom in heart failure (HF) is congestion, which can be refractory to diuretic treatment.

AIM

To verify whether, in patients with advanced HF and diuretic resistance, subcutaneous furosemide or furosemide in an oral solution can improve the clinical-analytical status.

METHODS

From 2018 to 2020, 27 consecutive outpatients with diuretic resistance, not candidates for other alternatives, were recruited. Patients were treated either with subcutaneous furosemide in elastomeric pump (n: 10) or with oral solution (n: 17) for 5 days.

RESULTS

The functional status (NYHA) improved with subcutaneous administration (predose: 3.8 ± 0.5 vs. postdose: 3.1 ± 0.7; p: 0.02) and oral solution (predose: 3.7 ± 0.3 vs. postdose: 2.5 ± 0.7; p: 0.0001). Weight loss was greater with the oral solution (predose: 85.5 ± 19.5 vs. postdose: 81.3 ± 18.8Kg; p: 0.0001) than subcutaneous (predose: 81.6 ± 15.9 vs. postdose: 80.4 ± 15.1kg; p: 0.16). Creatinine showed a non-significant increase in both groups. The number of hospital visits showed no difference between both options.

CONCLUSIONS

The administration of furosemide, both subcutaneously by elastomeric pump or drinking the oral solution, is effective for the treatment of congestion in advanced HF refractory to diuretic treatment.

[Hypertonic saline solution and high dose of diuretic, ¿what do we know and how can we use them in persistent congestion?]

The presence of decompensated heart failure continues to be a condition with high rates of hospitalization, impact on the health system, and quality of life for those who suffer it. The mainstay of treatment in these cases are diuretics. However, the resistance to this pharmacological group may occasionally occur, generating an inadequate negative fluid balance and persistence of congestion with negative clinical outcomes. Hypertonic saline solution with high doses of diuretic emerges as a therapeutic option for this group of patients with probable physiological, and clinical benefits on hospitalization and re-admission rates due to heart failure decompensation. A review of the most relevant aspects and benefits of this combination is discussed in this article.

Effects of Metolazone Administration on Congestion, Diuretic Response and Renal Function in Patients with Advanced Heart Failure

Background: Advanced heart failure (HF) is a condition often requiring elevated doses of loop diuretics. Therefore, these patients often experience poor diuretic response. Both conditions have a detrimental impact on prognosis and hospitalization. Aims: This retrospective, multicenter study evaluates the effect of the addition of oral metolazone on diuretic response (DR), clinical congestion, NTproBNP values, and renal function over hospitalization phase. Follow-up analysis for a 6-month follow-up period was performed. Methods: We enrolled 132 patients with acute decompensated heart failure (ADHF) in advanced NYHA class with reduced ejection fraction (EF < 40%) taking a mean furosemide amount of 250 ± 120 mg/day. Sixty-five patients received traditional loop diuretic treatment plus metolazone (Group M). The mean dose ranged from 7.5 to 15 mg for one week. Sixty-seven patients continued the furosemide (Group F). Congestion score was evaluated according to the ESC recommendations. DR was assessed by the formula diuresis/40 mg of furosemide. Results: Patients in Group M and patients in Group F showed a similar prevalence of baseline clinical congestion (3.1 ± 0.7 in Group F vs. 3 ± 0.8 in Group M) and chronic kidney disease (CKD) (51% in Group M vs. 57% in Group F; p = 0.38). Patients in Group M experienced a better congestion score at discharge compared to patients in Group F (C score: 1 ± 1 in Group M vs. 3 ± 1 in Group F p > 0.05). Clinical congestion resolution was also associated with weight reduction (−6 ± 2 in Group M vs. −3 ± 1 kg in Group F, p < 0.05). Better DR response was observed in Group M compared to F (940 ± 149 mL/40 mgFUROSEMIDE/die vs. 541 ± 314 mL/40 mgFUROSEMIDE/die; p < 0.01), whereas median ΔNTproBNP remained similar between the two groups (−4819 ± 8718 in Group M vs. −3954 ± 5560 pg/mL in Group F NS). These data were associated with better daily diuresis during hospitalization in Group M (2820 ± 900 vs. 2050 ± 1120 mL p < 0.05). No differences were found in terms of WRF development and electrolyte unbalance at discharge, although Group M had a significant saline solution administration during hospitalization. Follow-up analysis did not differ between the group but a reduced trend for recurrent hospitalization was observed in the M group (26% vs. 38%). Conclusions: Metolazone administration could be helpful in patients taking an elevated loop diuretics dose. Use of thiazide therapy is associated with better decongestion and DR. Current findings could suggest positive insights due to the reduced amount of loop diuretics in patients with advanced HF.

Simultaneous Use of Hypertonic Saline and IV Furosemide for Fluid Overload: A Systematic Review and Meta-Analysis

OBJECTIVES

To evaluate the efficacy of the simultaneous hypertonic saline solution and IV furosemide (HSS+Fx) for patients with fluid overload compared with IV furosemide alone (Fx).

DATA SOURCES

Electronic databases (MEDLINE, EMBASE, CENTRAL, Cochrane Database of Systematic Reviews, PsycINFO, Scopus, and WOS) were searched from inception to March 2020.

STUDY SELECTION

Randomized controlled trials on the use of HSS+Fx in adult patients with fluid overload versus Fx were included.

DATA EXTRACTION

Data were collected on all-cause mortality, hospital length of stay, heart failure-related readmission, along with inpatient weight loss, change of daily diuresis, serum creatinine, and 24-hour urine sodium excretion from prior to post intervention. Pooled analysis with random effects models yielded relative risk or mean difference with 95% CIs.

DATA SYNTHESIS

Eleven randomized controlled trials comprising 2,987 acute decompensated heart failure patients were included. Meta-analysis demonstrated that HSS+Fx was associated with lower all-cause mortality (relative risk, 0.55; 95% CI, 0.46-0.67; p < 0.05; I2 = 12%) and heart failure-related readmissions (relative risk, 0.50; 95% CI, 0.33-0.76; p < 0.05; I2 = 61%), shorter hospital length of stay (mean difference, -3.28 d; 95% CI, -4.14 to -2.43; p < 0.05; I2 = 93%), increased daily diuresis (mean difference, 583.87 mL; 95% CI, 504.92-662.81; p < 0.05; I2 = 76%), weight loss (mean difference, -1.76 kg; 95% CI, -2.52 to -1.00; p < 0.05; I2 = 57%), serum sodium change (mean difference, 6.89 mEq/L; 95% CI, 4.98-8.79; p < 0.05; I2 = 95%), and higher 24-hour urine sodium excretion (mean difference, 61.10 mEq; 95% CI, 51.47-70.73; p < 0.05; I2 = 95%), along with decreased serum creatinine (mean difference, -0.46 mg/dL; 95% CI, -0.51 to -0.41; p < 0.05; I2 = 89%) when compared with Fx. The Grading of Recommendation, Assessment, Development, and Evaluation certainty of evidence ranged from low to moderate.

CONCLUSIONS

Benefits of the HSS+Fx over Fx were observed across all examined outcomes in acute decompensated heart failure patients with fluid overload. There is at least moderate certainty that HSS+Fx is associated with a reduction in mortality in patients with acute decompensated heart failure. Factors associated with a successful HSS+Fx utilization are still unknown. Current evidence cannot be extrapolated to other than fluid overload states in acute decompensated heart failure.

Induction of renal tumor necrosis factor-α and other autacoids and the beneficial effects of hypertonic saline in acute decompensated heart failure

Although administration of hypertonic saline (HSS) in combination with diuretics has yielded improved weight loss, preservation of renal function, and reduction in hospitalization time in the clinical setting of patients with acute decompensated heart failure (ADHF), the mechanisms that underlie these beneficial effects remain unclear and additional studies are needed before this approach can be adopted on a more consistent basis. As high salt conditions stimulate the production of several renal autacoids that exhibit natriuretic effects, renal physiologists can contribute to the understanding of mechanisms by which HSS leads to increased diuresis both as an individual therapy as well as in combination with loop diuretics. For instance, since HSS increases TNF-α production by proximal tubule and thick ascending limb of Henle's loop epithelial cells, this article is aimed at highlighting how the effects of TNF-α produced by these cell types may contribute to the beneficial effects of HSS in patients with ADHF. Although TNF-α produced by infiltrating macrophages and T cells exacerbates and attenuates renal damage, respectively, production of this cytokine within the tubular compartment of the kidney functions as an intrinsic regulator of blood pressure and Na⁺ homeostasis via mechanisms along the nephron related to inhibition of Na⁺-K⁺-2Cl^- cotransporter isoform 2 activity and angiotensinogen expression. Thus, in the clinical setting of ADHF and hyponatremia, induction of TNF-α production along the nephron by administration of HSS may attenuate Na⁺-K⁺-2Cl^- cotransporter isoform 2 activity and angiotensinogen expression as part of a mechanism that prevents excessive Na⁺ reabsorption in the thick ascending limb of Henle's loop, thereby mitigating volume overload.

Efficiency of Hypertonic Saline in the Management of Decompensated Heart Failure: A Systematic Review and Meta-Analysis of Clinical Studies

INTRODUCTION

Acute decompensated heart failure (ADHF), with an incidence of 1-2%, is a clinical syndrome with significant morbidity and mortality despite therapeutic advancements and ongoing clinical trials. A recent therapeutic approach to patients with ADHF includes combination therapy with hypertonic saline solution (HSS) and furosemide, based on the hypothesis that resistance to loop diuretics occurs because of achievement of plateau in water and sodium excretion in patients receiving long-term loop diuretic therapy.

OBJECTIVE

Our aim was to conduct a meta-analysis to evaluate the efficiency of combination HSS plus furosemide therapy in patients with ADHF in terms of mortality, readmissions, length of hospital stay, kidney function, urine output, body weight, and B-type natriuretic peptide (BNP).

METHODS

A total of 14 studies-four observational and ten randomized studies (total 3398 patients)-were included in the meta-analysis.

RESULTS

Our results demonstrate the superiority of combination HSS plus furosemide therapy over furosemide alone in terms of kidney function preservation (mean creatinine difference - 0.33 mg/dL; P < 0.00001), improved diuresis (mean difference [MD] 581.94 mL/24 h; P < 0.00001) and natriuresis (MD 57.19; P < 0.00001), weight loss (MD 0.99 kg; P < 0.00001), duration of hospital stay (MD - 2.72 days; P < 0.00001), readmissions (relative risk 0.63; P = 0.01), and mortality (relative risk 0.55; P < 0.00001). However, no difference in BNP levels was detected (MD 19.88 pg/mL; P = 0.50).

CONCLUSION

Despite the heterogeneity and possible risk of bias among the studies, results appear promising on multiple aspects. A clear need exists for future randomized controlled trials investigating the role of combination HSS plus furosemide therapy to clarify these effects and their possible mechanisms.