Bumetanide and furosemide in heart failure

Serial evaluation of loop diuretic efficiency following left ventricular assist device implantation

More than 50% of heart failure (HF) patients require diuretic therapy after left ventricular assist device (LVAD). Although few data related to diuretic response (DR) exist in stage D patients, tubular sodium reabsorption may be clinically prognostic independent of estimated glomerular filtration rate (eGFR) and proteinuria within this cohort. We aimed to characterize DR serially before and after LVAD implantation in a stage D population. We conducted a prospective, observational cohort study of HF patients receiving diuretics with plans to undergo LVAD implantation. We measured urine sodium (UNa) and creatinine (UCr) at three points after diuretic therapy: pre-LVAD, post-LVAD prior to discharge, and as an outpatient. Prior to LVAD, patients (N = 19) had an average eGFR of 54.0 ± 18.0 mL/min/1.73 m2, spot UNa of 74.8 ± 28.0 mmol/L, and fractional excretion of sodium (FENa) of 3.1 ± 2.7%. Pre-LVAD, eGFR did not correlate with spot UNa nor FENa (p > 0.05 for both). LVAD implantation did not improve DR post-LVAD (mean change FENa per 40 mg IV furosemide 0.5 ± 1.0%; p = 0.84), and 90% of patients required loop diuretics at 90 days post-surgery. Improved hemodynamics following LVAD may not improve DR or tubular function; larger studies are needed to confirm our results and assess the utility of DR to predict post-LVAD outcomes.

Pulmonary Artery Pressure-Guided Heart Failure Management Reduces Hospitalizations in Patients With Chronic Kidney Disease

BACKGROUND

Hemodynamic-guided heart failure management is a superior strategy to prevent decompensation leading to hospitalization compared with traditional clinical methods. It remains unstudied if hemodynamic-guided care is effective across severities of comorbid renal insufficiency or if this strategy impacts renal function over time.

METHODS

In the CardioMEMS US PAS (Post-Approval Study), heart failure hospitalizations were compared from 1 year before and after pulmonary artery sensor implantation in 1200 patients with New York Heart Association class III symptoms and a previous hospitalization. Hospitalization rates were evaluated in all patients grouped into baseline estimated glomerular filtration rate (eGFR) quartiles. Chronic kidney disease progression was evaluated in patients with renal function follow-up data (n=911).

RESULTS

Patients with stage 2 or greater chronic kidney disease at baseline exceeded 80%. Heart failure hospitalization risk was lower in all eGFR quartiles ranging from a hazard ratio of 0.35 (0.27-0.46; P<0.0001) in patients with eGFR >65 mL/min per 1.73 m2 to 0.53 (0.45-0.62; P<0.0001) in patients with eGFR ≤37 mL/min per 1.73 m2. Renal function was preserved or improved in most patients. Survival was different between quartiles and lower in quartiles with more advanced chronic kidney disease.

CONCLUSIONS

Hemodynamic-guided heart failure management using remotely obtained pulmonary artery pressures is associated with lower hospitalization rates and general preservation of renal function in all eGFR quartiles or chronic kidney disease stages.

Diuretic and renal effects of angiotensin receptor-neprilysin inhibitor in patients hospitalized for acute heart failure

In patients hospitalized for acute decompensation of heart failure (HF), the impact of angiotensin receptor-neprilysin inhibitor (ARNI) on diuresis and renal function has not been fully investigated. Patients with HF and reduced ejection fraction who were hospitalized for acute decompensation and newly initiated ARNI after hemodynamic stabilization were enrolled. Changes in urine volume (UV), body weight, estimated glomerular filtration rate (eGFR), and urine N-acetyl-beta-d-glucosaminidase (uNAG) levels before and after ARNI initiation were investigated. Changes in the diuretic response [DR, calculated as urine volume/(intravenous furosemide volume/40 mg)], N-terminal pro-brain natriuretic peptide (NT-proBNP), hematocrit, and plasma volume (PV) were also evaluated. A total of 60 patients were enrolled. ARNI was initiated at a median of 6 [5, 7] days after hospitalization. After initiation of ARNI, body weight, NT-proBNP, and PV decreased. UV and DR increased only on the day of ARNI initiation (delta UV 400 ± 957 ml and delta DR 1100 ± 3107 ml/40 mg furosemide) and then decreased to baseline levels. In the multivariable linear regression analysis, younger age, higher BMI, and higher NT-proBNP levels were significantly associated with greater UV after ARNI initiation. eGFR and uNAG did not significantly change after the initiation of ARNI [delta eGFR -1.7 ± 12.0 mL/min/1.73 m² and delta uNAG 2.0 (-5.6, 6.9) IU/L]. In patients hospitalized for HF, the initiation of ARNI was associated with a small and transient increase in UV and DR, and was not associated with worsening of renal function or tubular injury.

Population Pharmacokinetics of Vericiguat in Patients with Heart Failure with Reduced Ejection Fraction: An Integrated Analysis

Vericiguat, a novel stimulator of soluble guanylate cyclase (sGC), is indicated for the treatment of patients following a hospitalization for heart failure or need for outpatient IV diuretics, with symptomatic chronic heart failure and ejection fraction less than 45%. Pharmacokinetic (PK) data from the phase II trial SOCRATES-REDUCED (SOluble guanylate Cyclase stimulatoR in heArT failurE Study) and the phase III trial VICTORIA (Vericiguat Global Study in Patients with Heart Failure with Reduced Ejection Fraction) were used to characterize vericiguat PK. A total of 8,092 concentration records from 2,321 participants (362 from SOCRATES-REDUCED and 1,959 from VICTORIA) were utilized for the development of the population PK (PPK) model. The final PK model was a one-compartment model with first-order absorption and linear elimination. Baseline body weight and time-varying body weight were identified as statistically significant covariates affecting apparent clearance (CL/F) and volume of distribution (V_c ), respectively. Age, sex, race, bilirubin, estimated glomerular filtration rate (eGFR), and albumin did not affect vericiguat PK. Baseline disease-related factors, such as left ventricular ejection fraction, New York Heart Association (NYHA) class, and N-terminal pro B-type natriuretic peptide (NT-proBNP), also did not influence vericiguat PK. Since vericiguat is a titrated drug, the impact of vericiguat PK on the titration to and maintenance of the target dose in VICTORIA was assessed. The distribution of steady-state doses in VICTORIA was similar across CL/F quartiles, suggesting that the ability to reach and maintain dosing at the target 10 mg dose was not related to vericiguat exposure.

An evaluation of torsemide in patients with heart failure and renal disease

INTRODUCTION

Torsemide is a loop diuretic that inhibits the Na+/K+/2Cl- cotransporter type 2 in the thick ascending loop of Henle, leading to increased excretion of urinary sodium and chloride and associated diuresis. While furosemide remains the dominant diuretic utilized in current practice, increasing evidence supports potential advantages of torsemide in heart failure (HF) and/or renal disease.

AREAS COVERED

This narrative review covers the evidence for use of torsemide in HF and renal disease. Comparative effectiveness with regards to clinical outcomes is reviewed, as well as the ongoing multicenter trial, TRANSFORM-HF, comparing the effect of torsemide versus furosemide among patients with HF.

EXPERT OPINION

Compared with furosemide, torsemide has favorable pharmacodynamics/pharmacokinetics including higher bioavailability, longer duration of effect, minor renal excretion, decreased kaliuresis, and enhanced natriuresis/diuresis. These properties may be further supported by differential effects on RAAS regulation and fibrosis modulation as compared with other diuretics. The limited current body of evidence indicates that torsemide may be superior to furosemide with respect to improving HF functional status and reducing HF hospitalization, and there are mixed data regarding effect on reducing overall cardiovascular hospitalizations/mortality. Further, randomized data are necessary to definitively determine if torsemide can reduce risk of mortality and hospitalization among patients with HF.

Mechanisms and management of edema in pediatric nephrotic syndrome

Edema is the abnormal accumulation of fluid in the interstitial compartment of tissues within the body. In nephrotic syndrome, edema is often seen in dependent areas such as the legs, but it can progress to cause significant accumulation in other areas leading to pulmonary edema, ascites, and/or anasarca. In this review, we focus on mechanisms and management of edema in children with nephrotic syndrome. We review the common mechanisms of edema, its burden in pediatric patients, and then present our approach and algorithm for management of edema in pediatric patients. The extensive body of experience accumulated over the last 5 decades means that there are many options, and clinicians may choose among these options based on their experience and careful monitoring of responses in individual patients.

Relation of Decongestion and Time to Diuretics to Biomarker Changes and Outcomes in Acute Heart Failure

Prompt treatment may mitigate the adverse effects of congestion in the early phase of heart failure (HF) hospitalization, which may lead to improved outcomes. We analyzed 814 acute HF patients for the relationships between time to first intravenous loop diuretics, changes in biomarkers of congestion and multiorgan dysfunction, and 1-year composite end point of death or HF hospitalization. B-type natriuretic peptide (BNP), high sensitivity cardiac troponin I (hscTnI), urine and serum neutrophil gelatinase-associated lipocalin, and galectin 3 were measured at hospital admission, hospital day 1, 2, 3 and discharge. Time to diuretics was not correlated with the timing of decongestion defined as BNP decrease ≥ 30% compared with admission. Earlier BNP decreases but not time to diuretics were associated with earlier and greater decreases in hscTnI and urine neutrophil gelatinase-associated lipocalin, and lower incidence of the composite end point. After adjustment for confounders, only no BNP decrease at discharge was significantly associated with mortality but not the composite end point (p = 0.006 and p = 0.062, respectively). In conclusion, earlier time to decongestion but not the time to diuretics was associated with better biomarker trajectories. Residual congestion at discharge rather than the timing of decongestion predicted a worse prognosis.

Clinical pearls in hospital nephrology

Hospitalized patients who have established kidney disease and those who have acute kidney injury in the hospital, along with patients with electrolyte disturbances tend to be some of the most complex to care for. Through working closely in nephrology consultation in the hospital with patients and providers, in both private and academic settings, we have come to encounter certain common presentations and recurrent themes that are worthy of emphasis, and of which a good understanding can translate into improved patient care. For the provider who works closely with such patients, many of these aspects are important to recognize and understand. In this review, we present 10 questions that address some of the highly relevant aspects of nephrology for the provider in the hospital. Through a MEDLINE database search, we reviewed the most pertinent studies as we then go through the explanation of management decisions in an evidence-based methodology with an up-to-date approach based on the current literature on the subject.

The pathophysiology and management of diuretic resistance in patients with heart failure

OBJECTIVES

The objectives of the study are to investigate the causes of diuretic resistance in patients with advanced congestive heart failure (CHF), since diuretics are the cornerstone of treatment of these patients. Several studies have shown that diuretic resistance in patients with advanced CHF is common, ranging from 25% to 50% in hospitalized patients.

METHODS

In order to get a current perspective as to the magnitude of diuretic resistance in such patients, a focused Medline search of the English language literature was conducted between 2015 and 2020 using the search terms, CHF, diuretics, treatment, resistance, frequency, and 30 papers with pertinent information were selected.

RESULTS

The analysis of data from the selected papers demonstrated that diuretic resistance is common in hospitalized patients with advanced CHF and frequently associated with renal failure, which is secondary to CHF.

CONCLUSIONS

Diuretic resistance appears to be common in patients with advanced CHF and it is mostly due to decreased cardiac output, low blood pressure, decreased glomerular filtration rate, decreased filtration of sodium, and increased tubular reabsorption of sodium. Diuretic resistance in such patients can be overcome with the combination of loop diuretics with thiazide and thiazide-like diuretics, aldosterone antagonists, as well as other agents. The data from these studies in combination with collateral literature will be discussed in this review.

Natriuretic Equation to Predict Loop Diuretic Response in Patients With Heart Failure

BACKGROUND

Most acute decompensated heart failure admissions are driven by congestion. However, residual congestion is common and often driven by the lack of reliable tools to titrate diuretic therapy. The authors previously developed a natriuretic response prediction equation (NRPE), which predicts sodium output using a spot urine sample collected 2 h after loop diuretic administration.

OBJECTIVES

The purpose of this study was to validate the NRPE and describe proof-of-concept that the NRPE can be used to guide diuretic therapy.

METHODS

Two cohorts were assembled: 1) the Diagnosing and Targeting Mechanisms of Diuretic Resistance (MDR) cohort was used to validate the NRPE to predict 6-h sodium output after a loop diuretic, which was defined as poor (<50 mmol), suboptimal (<100 mmol), or excellent (>150 mmol); and 2) the Yale Diuretic Pathway (YDP) cohort, which used the NRPE to guide loop diuretic titration via a nurse-driven automated protocol.

RESULTS

Evaluating 638 loop diuretic administrations, the NRPE showed excellent discrimination with areas under the curve ≥0.90 to predict poor, suboptimal, and excellent natriuretic response, and outperformed clinically obtained net fluid loss (p < 0.05 for all cutpoints). In the YDP cohort (n = 161) using the NRPE to direct therapy mean daily urine output (1.8 ± 0.9 l vs. 3.0 ± 0.8 l), net fluid output (-1.1 ± 0.9 l vs. -2.1 ± 0.9 l), and weight loss (-0.3 ± 0.3 kg vs. -2.5 ± 0.3 kg) improved substantially following initiation of the YDP (p < 0.001 for all pre-post comparisons).

CONCLUSIONS

Natriuretic response can be rapidly and accurately predicted by the NRPE, and this information can be used to guide diuretic therapy during acute decompensated heart failure. Additional study of diuresis guided by the NRPE is warranted.

Association of Visit-to-Visit Variability in Kidney Function and Serum Electrolyte Indexes With Risk of Adverse Clinical Outcomes Among Patients With Heart Failure With Preserved Ejection Fraction

Importance

Although kidney dysfunction and abnormalities in serum electrolyte levels are associated with poor clinical outcomes in patients with heart failure with preserved ejection fraction (HFpEF), the association of visit-to-visit variability in such laboratory measures with long-term outcomes is unclear.

Objective

To evaluate the associations of visit-to-visit variability in indexes of kidney function (creatinine and blood urea nitrogen [BUN] levels) and serum electrolyte (sodium, chloride, and potassium) with the risk of adverse clinical outcomes among patients with chronic, stable HFpEF.

Design, Setting, and Participants

This cohort analysis used data from the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial. All participants with 3 or more serial laboratory measurements who were event free within the first 4 months of enrollment were included. Data were analyzed from March 1, 2019, to January 31, 2020.

Main Outcomes and Measures

Adjusted associations between indexes of variability in serum laboratory measurements during the first 4 months of follow-up and risk of the primary composite outcome (a composite of aborted cardiac arrest, hospitalization for heart failure, or cardiovascular death) and all-cause mortality were assessed using Cox proportional hazards regression models.

Results

Of the 3445 patients enrolled in the TOPCAT trial (mean [SD] age, 68-69 [10] years; 49.7%-51.5% female), 2479 (BUN) to 3195 (potassium) were analyzed, depending on availability of serial measurements. Participants with higher laboratory variability in kidney function parameters were older, had more comorbidities, and had more severe symptoms of HFpEF. Higher visit-to-visit variability in BUN (hazard ratio [HR] per 1-SD higher average successive variability [ASV], 1.21; 95% CI, 1.10-1.33) and creatinine (HR per 1-SD higher ASV, 1.13; 95% CI, 1.04-1.22) were independently associated with a higher risk of the primary composite outcome as well as mortality independent of other baseline confounders, changes in kidney function, changes in medication dosages, and variability in other cardiometabolic parameters (systolic blood pressure and body mass index). The higher risk associated with greater variability in kidney function was consistent across subgroups of patients stratified by the presence of chronic kidney disease (CKD) at baseline (CKD: HR per 1-SD higher ASV, 1.39; 95% CI, 1.16-1.67 and no CKD: HR per 1-SD higher ASV, 1.13; 95% CI, 1.01-1.27), among placebo and spironolactone treatment arms separately (spironolactone arm: 1.30; 95% CI, 1.03-1.65 and placebo arm: HR per 1-SD higher ASV, 1.27; 95% CI, 1.04-1.56). Among serum electrolytes, variability in sodium and potassium measures were also significantly associated with a higher risk of primary composite events (sodium: HR per 1-SD higher ASV, 1.14; 95% CI, 1.01-1.30 and potassium: HR per 1-SD higher ASV, 1.21; 95% CI, 1.02-1.44).

Conclusions and Relevance

In HFpEF, visit-to-visit variability in laboratory indexes of kidney function and serum electrolytes is common and independently associated with worse long-term clinical outcomes.

Assessment of fluid resuscitation on time to hemodynamic stability in obese patients with septic shock

PURPOSE

Assess time to hemodynamic stability (HDS) in obese patients with septic shock who received <30 vs. ≥30 ml/kg of initial fluid resuscitation based on actual body weight (ABW).

MATERIALS AND METHODS

Multicenter, retrospective, cohort analysis of 322 patients.

RESULTS

Overall 216 (67%) patients received <30 ml/kg of initial fluid resuscitation. Initial fluid received was lower in the <30 ml/kg vs. ≥30 ml/kg group (16 vs. 37 ml/kg). The ≥30 ml/kg group had shorter time to HDS (multivariable p = 0.038) and lower riskof in-hospital death (multivariable p = 0.038). An exploratory subgroup analysis (n = 227) was performed, classifying patients by dosing strategy [ABW, adjusted body weight (AdjBW), ideal body weight (IBW)] based on fluid received at 3 h divided by 30 ml/kg. ABW dosed patients had a shorter time to HDS (multivariable p = 0.013) and lower risk of in-hospital death (multivariable p = 0.008) vs. IBW. Similar outcomes were observed between ABW vs. AdjBW.

CONCLUSIONS

Obese patients given ≥30 ml/kg based on ABW had a shorter time to HDS and a lower risk of in-hospital death. Exploratory results suggest improved outcomes resuscitating by ABW vs. IBW; ABW showed no strong benefit over AdjBW. Further prospective studies are needed to confirm the optimal fluid dosing in obese patients.

Elastic Bandage vs Hypertonic Albumin for Diuretic-Resistant Volume-Overloaded Patients in Intensive Care Unit: A Propensity-Match Study

OBJECTIVE

To compare elastic bandage (EB) vs hypertonic albumin solution administration to increase fluid removal by enhancing loop diuretic efficiency (DE) in patients with volume overload and diuretic resistance.

PATIENTS AND METHODS

In this historic cohort study with propensity matching, we included diuretic-resistant adult (≥18 years) patients with volume overload after fluid resuscitation admitted in the intensive care unit from January 1, 2006, through June 30, 2017. Regression models and propensity matching were used to assess the associations of these interventions with changes in DE and other clinical outcomes.

RESULTS

Of 1147 patients (median age, 66; interquartile range [IQR], 56-76 years; 51% [n=590] men), 384 (33%) received EB and 763 (67%) received hypertonic albumin solution. In adjusted models, EB was significantly associated with higher DE compared with hypertonic albumin solution (odds ratio, 1.37; 95% CI, 1.04 to 1.81; P=.004). After propensity matching of 345 pairs, DE remained significantly different between the 2 groups (median, 2111; IQR, 1092 to 4665 mL for EB vs median, 1829; IQR, 1032 to 3436 mL for hypertonic albumin solution; P=.02). EB, male sex, lower baseline serum urea nitrogen level, lower Charlson Comorbidity Index score, and higher baseline left ventricular ejection fraction were DE determinants. The lowest DE quartile (<1073 mL/40-mg furosemide equivalent) following adjustment for known predictors of mortality remained independently associated with higher 90-day death rate (odds ratio, 1.64; 95% CI, 1.13 to 2.36; P=.009).

CONCLUSION

EB use is associated with greater DE than hypertonic albumin solution during the deescalation phase of sepsis resuscitation. Prospective clinical trials would validate the findings of this hypothesis-generating study.

Treatment outcomes of bumetanide continuous infusion: A systematic review and meta-analysis

The clinical use of continuous bumetanide infusion for acute heart failure and volume overload is common. However, there is not enough supporting evidence for the use of continuous bumetanide infusion. Thus, we conducted this systematic review and meta-analysis aiming to describe the treatment outcomes of continuous bumetanide infusion. We searched Ovid MEDLINE, EMBASE and the Cochrane Library for eligible publications. Inclusion criteria were patients age ≥18 years with bumetanide infusion for heart failure, acute kidney injury (AKI) or volume overload. From 1564 citations, three studies (n = 94 patients) were included in the systematic review and meta-analysis. The mean dose of bumetanide was 1.08 ± 0.43 mg/hour with a mean treatment duration of 45.09 ± 10.12 hours. Mean urine output in response to continuous bumetanide infusion was 1.88 mL/kg/hour (95% confidence interval [CI], 1.72-2.05). The incidence of AKI with continuous bumetanide infusion was 24.7% (95% CI, 8.2-54.6). By using Pearson's correlation coefficient, increasing doses of bumetanide were correlated with increased urine output (P = .026) and increased incidence of AKI (P < .01). There was no correlation between increasing urine output and the incidence of AKI (P = .739). In conclusion, with available evidence, continuous bumetanide infusion may be used in the treatment of acute heart failure or volume overload with close monitoring for new-onset or worsening AKI.

Contribution of Monocarboxylate Transporter 6 to the Pharmacokinetics and Pharmacodynamics of Bumetanide in Mice

Bumetanide, a sulfamyl loop diuretic, is used for the treatment of edema in association with congestive heart failure. Being a polar, anionic compound at physiologic pH, bumetanide uptake and efflux into different tissues is largely transporter-mediated. Of note, organic anion transporters (SLC22A) have been extensively studied in terms of their importance in transporting bumetanide to its primary site of action in the kidney. The contribution of one of the less-studied bumetanide transporters, monocarboxylate transporter 6 (MCT6; SLC16A5), to bumetanide pharmacokinetics (PK) and pharmacodynamics (PD) has yet to be characterized. The affinity of bumetanide for murine Mct6 was evaluated using Mct6-transfected Xenopus laevis oocytes. Furthermore, bumetanide was intravenously and orally administered to wild-type mice (Mct6^+/+) and homozygous Mct6 knockout mice (Mct6^-/-) to elucidate the contribution of Mct6 to bumetanide PK/PD in vivo. We demonstrated that murine Mct6 transports bumetanide at a similar affinity compared with human MCT6 (78 and 84 μM, respectively, at pH 7.4). After bumetanide administration, there were no significant differences in plasma PK. Additionally, diuresis was significantly decreased by ∼55% after intravenous bumetanide administration in Mct6^-/- mice. Kidney cortex concentrations of bumetanide were decreased, suggesting decreased Mct6-mediated bumetanide transport to its site of action in the kidney. Overall, these results suggest that Mct6 does not play a major role in the plasma PK of bumetanide in mice; however, it significantly contributes to bumetanide's pharmacodynamics due to changes in kidney concentrations. SIGNIFICANCE STATEMENT: Previous evidence suggested that MCT6 transports bumetanide in vitro; however, no studies to date have evaluated the in vivo contribution of this transporter. In vitro studies indicated that mouse and human MCT6 transport bumetanide with similar affinities. Using Mct6 knockout mice, we demonstrated that murine Mct6 does not play a major role in the plasma pharmacokinetics of bumetanide; however, the pharmacodynamic effect of diuresis was attenuated in the knockout mice, likely because of the decreased bumetanide concentrations in the kidney.

Torasemide versus furosemide in treatment of heart failure: A systematic review and meta-analysis of randomized controlled trials

AIM

Diuretics are a cornerstone in treatment of heart failure (HF). Torasemide is a loop diuretic with a potential advantage over other diuretics. We aim to meta-analyse and compare the effect of torasemide with furosemide in HF patients.

METHODS

A comprehensive literature search using 12 databases including PubMed, Scopus, and Web of Science was performed. All randomized controlled trials (RCTs) comparing furosemide and torasemide in HF patients were included and meta-analysed. We assessed the risk of bias using Cochrane Collaboration's tool. The protocol was registered in PROSPERO (CRD42016046112).

RESULTS

Eighteen RCTs with 1598 patients were included. There was a significant difference between torasemide 20 mg and furosemide 40 mg in increasing the urine volume (standard difference of the mean (SDM) [95% confidence interval] = -0.78 [-1.52 to -0.053], P = .036). Torasemide 10 mg and 10 to 20 mg have a significant effect on potassium excretion in comparison with furosemide 25 to 40 mg (P = .018 and .023, respectively). In general, torasemide and furosemide have no significant difference in mortality, edema improvement, weight loss, heart rate, and reducing systolic/diastolic blood pressure. However, oral torasemide has a significant lower hospital stay P < .001 and superior effect in improving ejection fraction P = .029.

CONCLUSION

Although not all results are statistically significant, torasemide has potential advantages on multiple aspects of HF management when compared with furosemide. More studies are needed to clarify these effects.

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

OBJECTIVES

The purpose of this study was to investigate real world safety and efficacy of hypertonic saline therapy in cases of refractory acute decompensated heart failure (ADHF) at a large U.S. academic medical center.

BACKGROUND

Hypertonic saline therapy has been described as a potential management strategy for refractory ADHF, but experience in the United States is limited.

METHODS

A retrospective analysis was performed in all patients receiving hypertonic saline for diuretic therapy-resistant ADHF at the authors' institution since March 2013. The primary analytic approach was a comparison of the trajectory of clinical variables prior to and after administration of hypertonic saline, with secondary focus on predictors of treatment response.

RESULTS

A total of 58 hypertonic saline administration episodes were identified across 40 patients with diuretic-therapy refractory ADHF. Prior to hypertonic saline administration, serum sodium, chloride, and creatinine concentrations were worsening but improved after hypertonic saline administration (p < 0.001, all). Both total urine output and weight loss significantly improved with hypertonic saline (p = 0.01 and <0.001, respectively). Diuretic efficiency, defined as change in urine output per doubling of diuretic dose, also improved over this period (p < 0.01). There were no significant changes in respiratory status or overcorrection of serum sodium with the intervention.

CONCLUSIONS

In a cohort of patients who were refractory to ADHF, hypertonic saline administration was associated with increased diuretic efficiency, fluid and weight loss, and improvement of metabolic derangements, and no adverse respiratory or neurological signals were identified. Additional study of hypertonic saline as a diuretic adjuvant is warranted.

Outcomes Associated With a Strategy of Adjuvant Metolazone or High-Dose Loop Diuretics in Acute Decompensated Heart Failure: A Propensity Analysis

Background

In acute decompensated heart failure, guidelines recommend increasing loop diuretic dose or adding a thiazide diuretic when diuresis is inadequate. We set out to determine the adverse events associated with a diuretic strategy relying on metolazone or high‐dose loop diuretics.

Methods and Results

Patients admitted to 3 hospitals using a common electronic medical record with a heart failure discharge diagnosis who received intravenous loop diuretics were studied in a propensity‐adjusted analysis of all‐cause mortality. Secondary outcomes included hyponatremia (sodium <135 mEq/L), hypokalemia (potassium <3.5 mEq/L) and worsening renal function (a ≥20% decrease in estimated glomerular filtration rate). Of 13 898 admissions, 1048 (7.5%) used adjuvant metolazone. Metolazone was strongly associated with hyponatremia, hypokalemia, and worsening renal function (P<0.0001 for all) with minimal effect attenuation following covariate and propensity adjustment. Metolazone remained associated with increased mortality after multivariate and propensity adjustment (hazard ratio=1.20, 95% confidence interval 1.04–1.39, P=0.01). High‐dose loop diuretics were associated with hypokalemia and hyponatremia (P<0.002) but only worsening renal function retained significance (P<0.001) after propensity adjustment. High‐dose loop diuretics were not associated with reduced survival after multivariate and propensity adjustment (hazard ratio=0.97 per 100 mg of IV furosemide, 95% confidence interval 0.90–1.06, P=0.52).

Conclusions

During acute decompensated heart failure, metolazone was independently associated with hypokalemia, hyponatremia, worsening renal function and increased mortality after controlling for the propensity to receive metolazone and baseline characteristics. However, under the same experimental conditions, high‐dose loop diuretics were not associated with hypokalemia, hyponatremia, or reduced survival. The current findings suggest that until randomized control trial data prove otherwise, uptitration of loop diuretics may be a preferred strategy over routine early addition of thiazide type diuretics when diuresis is inadequate.

The influence of heart failure on the pharmacokinetics of cardiovascular and non-cardiovascular drugs: a critical appraisal of the evidence

Prescribing in heart failure (HF), a common disease state that predominantly affects the older population, is often a challenging task because of the dynamic nature of the condition, requiring frequent monitoring and medication review, the presence of various comorbidities, and the frailty phenotype of many patients. The significant alterations in various organs and tissues occurring in HF, particularly the reduced cardiac output with peripheral hypoperfusion and the structural and functional changes of the gastrointestinal tract, liver and kidney, might affect the pharmacokinetics of several drugs. This review critically appraises the results of published studies investigating the pharmacokinetics of currently marketed cardiovascular and selected non-cardiovascular drugs in HF patients and control groups, identifies gaps in the current knowledge, and suggests avenues for future research in this complex patient population.

Drug therapies in chronic heart failure: a focus on reduced ejection fraction

There are multiple evidence-based drug treatments for chronic heart failure (HF), both disease-modifying agents and those for symptom control. The majority of the evidence base supports drugs used in HF with reduced left ventricular ejection fraction. The mainstay of disease modification involves manipulation of neurohormonal activation that occurs in HF. In addition to established angiotensin-converting enzyme inhibitors, beta blockers and mineralocorticoid receptor antagonists (MRAs), newer agents are now available such as the angiotensin receptor neprilysin inhibitors. Achieving the optimal drug regimen is complex and best performed by a specialist heart failure team. We aim to provide a comprehensive overview of contemporary drug therapies in chronic heart failure, as well as practical guidance for their use. There is a focus on treating patients with challenging comorbidities such as hypotension and chronic kidney disease (CKD), where a thorough understanding of drug therapy is essential. Multiple trials assessing the benefits of new therapies in HF, such as intravenous iron, are also ongoing.

Response to different furosemide doses predicts AKI progression in ICU patients with elevated plasma NGAL levels

BACKGROUND

Furosemide responsiveness (FR) is determined by urine output after furosemide administration and has recently been evaluated as a furosemide stress test (FST) for predicting severe acute kidney injury (AKI) progression. Although a standardized furosemide dose is required for FST, variable dosing is typically employed based on illness severity, including renal dysfunction in the clinical setting. This study aimed to evaluate whether FR with different furosemide doses can predict AKI progression. We further evaluated the combination of an AKI biomarker, plasma neutrophil gelatinase-associated lipocalin (NGAL), and FR for predicting AKI progression.

RESULTS

We retrospectively analyzed 95 patients who were treated with bolus furosemide in our medical-surgical intensive care unit. Patients who had already developed AKI stage 3 were excluded. A total of 18 patients developed AKI stage 3 within 1 week. Receiver operating curve analysis revealed that the area under the curve (AUC) values of FR and plasma NGAL were 0.87 (0.73-0.94) and 0.80 (0.67-0.88) for AKI progression, respectively. When plasma NGAL level was < 142 ng/mL, only one patient developed stage 3 AKI, indicating that plasma NGAL measurements were sufficient to predict AKI progression. We further evaluated the performance of FR in 51 patients with plasma NGAL levels > 142 ng/mL. FR was associated with AUC of 0.84 (0.67-0.94) for AKI progression in this population with high NGAL levels.

CONCLUSIONS

Although different variable doses of furosemide were administered, FR revealed favorable efficacy for predicting AKI progression even in patients with high plasma NGAL levels. This suggests that a combination of FR and biomarkers can stratify the risk of AKI progression in a clinical setting.

Management of Adult Heart Failure: Bolus versus Continuous Infusion Loop Diuretics, A Review of the Literature

In an aging population, decompensated heart failure accounts for a significant number of hospital admissions. The standard management for edema and congestion associated with heart failure is loop diuretic therapy. Traditionally, bolus-dosed furosemide has been used to manage the edema and congestion associated with heart failure. However, diuretic resistance can occur with bolus dosing, resulting in inadequate diuresis and further hemodynamic instability. Based on current literature, furosemide given by continuous infusion may now be the preferred agent and route for diuretic refractory heart failure. This article reviews the literature that compares bolus versus continuous infusion loop diuretics in adult heart failure.

A perspective on diuretic resistance in chronic congestive heart failure

Chronic congestive heart failure (CHF) is a complex disorder characterized by inability of the heart to keep up the demands on it, followed by the progressive pump failure and fluid accumulation. Although the loop diuretics are widely used in heart failure (HF) patients, both pharmacodynamic and pharmacokinetic alterations are thought to be responsible for diuretic resistance in these patients. Strategies to overcome diuretic resistance include sodium intake restriction, changes in diuretic dose and route of administration and sequential nephron diuretic therapy. In this review, we discuss the definition, prevalence, mechanism of development and management strategies of diuretic resistance in HF patients.

Symptom management challenges in heart failure: pharmacotherapy considerations

Heart failure is a chronic, progressive illness that is increasing in prevalence in the USA. Patients with advanced heart failure experience a high symptom burden that is comparable to patients with advanced cancer. Palliative care, however, is underutilized in patients with heart failure, and symptoms may go untreated as the disease progresses. A combination of pharmacologic and non-pharmacologic interventions should be used to address symptoms and maintain quality of life. While there have been significant advances in evidence-based heart failure treatments in recent years, selection of appropriate palliative medications as symptoms progress is challenging due to limited clinical studies in this patient population. Medications that are commonly used for symptom management in other life-limiting illnesses may have little to no evidence in heart failure, or have undesirable cardiac effects that preclude use. Clinicians must extrapolate available clinical evidence and prescribing considerations relevant to heart failure to palliate symptoms as well as possible. The objectives of this paper are to review the most common and distressing symptoms in heart failure, analyze evidence, or lack thereof, for pharmacologic management of symptoms, and provide prescribing considerations based on side effect profiles and comorbid conditions.

An exploratory analysis of the competing effects of aggressive decongestion and high-dose loop diuretic therapy in the DOSE trial

BACKGROUND

Effective decongestion of heart failure patients predicts improved outcomes, but high dose loop diuretics (HDLD) used to achieve diuresis predict adverse outcomes. In the DOSE trial, randomization to a HDLD intensification strategy (HDLD-strategy) improved diuresis but not outcomes. Our objective was to determine if potential beneficial effects of more aggressive decongestion may have been offset by adverse effects of the HDLD used to achieve diuresis.

METHODS AND RESULTS

A post hoc analysis of the DOSE trial (n=308) was conducted to determine the influence of post-randomization diuretic dose and fluid output on the rate of death, rehospitalization or emergency department visitation associated with the HDLD-strategy. Net fluid output was used as a surrogate for beneficial decongestive effects and cumulative loop diuretic dose for the dose-related adverse effects of the HDLD-strategy. Randomization to the HDLD-strategy resulted in increased fluid output, even after adjusting for cumulative diuretic dose (p=0.006). Unadjusted, the HDLD-strategy did not improve outcomes (p=0.28). However, following adjustment for cumulative diuretic dose, significant benefit emerged (HR=0.64, 95% CI 0.43-0.95, p=0.028). Adjusting for net fluid balance eliminated the benefit (HR=0.95, 95% CI 0.67-1.4, p=0.79).

CONCLUSIONS

A clinically meaningful benefit from a randomized aggressive decongestion strategy became apparent after accounting for the quantity of loop diuretic administered. Adjusting for the diuresis resulting from this strategy eliminated the benefit. These hypothesis-generating observations may suggest a role for aggressive decongestion in improved outcomes.

Renal tubular resistance is the primary driver for loop diuretic resistance in acute heart failure

BACKGROUND

Loop diuretic resistance is a common barrier to effective decongestion in acute heart failure (AHF), and is associated with poor outcome. Specific mechanisms underlying diuretic resistance are currently unknown in contemporary AHF patients. We therefore aimed to determine the relative importance of defects in diuretic delivery vs. renal tubular response in determining diuretic response (DR) in AHF.

METHODS AND RESULTS

Fifty AHF patients treated with intravenous bumetanide underwent a 6-h timed urine collection for sodium and bumetanide clearance. Whole-kidney DR was defined as sodium excreted per doubling of administered loop diuretic and represents the sum of defects in drug delivery and renal tubular response. Tubular DR, defined as sodium excreted per doubling of renally cleared (urinary) loop diuretic, captures resistance specifically in the renal tubule. Median administered bumetanide dose was 3.0 (2.0-4.0) mg with 52 (33-77)% of the drug excreted into the urine. Significant between-patient variability was present as the administered dose only explained 39% of variability in the quantity of bumetanide in urine. Cumulatively, factors related to drug delivery such as renal bumetanide clearance, administered dose, and urea clearance explained 28% of the variance in whole-kidney DR. However, resistance at the level of the renal tubule (tubular DR) explained 71% of the variability in whole-kidney DR.

CONCLUSION

Defects at the level of the renal tubule are substantially more important than reduced diuretic delivery in determining diuretic resistance in patients with AHF.

Extracardiac Signs of Fluid Overload in the Critically Ill Cardiac Patient: A Focused Evaluation Using Bedside Ultrasound

Fluid balance management is of great importance in the critically ill cardiac patient. Although intravenous fluids are a cornerstone therapy in the management of unstable patients, excessive administration coupled with cardiac dysfunction leads to elevation in central venous pressure and end-organ venous congestion. Fluid overload is known to have a detrimental effect on organ function and is responsible for significant morbidity in critically ill patients. Multisystem bedside point of care ultrasound imaging can be used to assess signs of fluid overload and venous congestion in critically ill patients. In this review we describe the ultrasonographic extracardiac signs of fluid overload and how they can be used to complement clinical evaluation to individualize patient management.

Relevance of Changes in Serum Creatinine During a Heart Failure Trial of Decongestive Strategies: Insights From the DOSE Trial

BACKGROUND

Worsening renal function (WRF) is a common endpoint in decompensated heart failure clinical trials because of associations between WRF and adverse outcomes. However, WRF has not universally been identified as a poor prognostic sign, challenging the validity of WRF as a surrogate endpoint. Our aim was to describe the associations between changes in creatinine and adverse outcomes in a clinical trial of decongestive therapies.

METHODS AND RESULTS

We investigated the association between changes in creatinine and the composite endpoint of death, rehospitalization or emergency room visit within 60 days in 301 patients in the Diuretic Optimization Strategies Evaluation (DOSE) trial. WRF was defined as an increase in creatinine >0.3 mg/dL and improvement in renal function (IRF) as a decrease >0.3 mg/dL. When examining linear changes in creatinine from baseline to 72 hours (the coprimary endpoint of DOSE), increasing creatinine was associated with lower risk for the composite outcome (HR = 0.81 per 0.3 mg/dL increase, 95% CI 0.67-0.98, P = .026). Compared with patients with stable renal function (n = 219), WRF (n = 54) was not associated with the composite endpoint (HR = 1.17, 95% CI = 0.77-1.78, P = .47). However, compared with stable renal function, there was a strong relationship between IRF (n = 28) and the composite endpoint (HR = 2.52, 95% CI = 1.57-4.03, P < .001).

CONCLUSION

The coprimary endpoint of the DOSE trial, a linear increase in creatinine, was paradoxically associated with improved outcomes. This was driven by absence of risk attributable to WRF and a strong risk associated with IRF. These results argue against using changes in serum creatinine as a surrogate endpoint in trials of decongestive strategies.

Rapid and Highly Accurate Prediction of Poor Loop Diuretic Natriuretic Response in Patients With Heart Failure

BACKGROUND

Removal of excess sodium and fluid is a primary therapeutic objective in acute decompensated heart failure and commonly monitored with fluid balance and weight loss. However, these parameters are frequently inaccurate or not collected and require a delay of several hours after diuretic administration before they are available. Accessible tools for rapid and accurate prediction of diuretic response are needed.

METHODS AND RESULTS

Based on well-established renal physiological principles, an equation was derived to predict net sodium output using a spot urine sample obtained 1 or 2 hours after loop diuretic administration. This equation was then prospectively validated in 50 acute decompensated heart failure patients using meticulously obtained timed 6-hour urine collections to quantify loop diuretic-induced cumulative sodium output. Poor natriuretic response was defined as a cumulative sodium output of <50 mmol, a threshold that would result in a positive sodium balance with twice-daily diuretic dosing. Following a median dose of 3 mg (2-4 mg) of intravenous bumetanide, 40% of the population had a poor natriuretic response. The correlation between measured and predicted sodium output was excellent (r=0.91; P<0.0001). Poor natriuretic response could be accurately predicted with the sodium prediction equation (area under the curve =0.95, 95% confidence interval 0.89-1.0; P<0.0001). Clinically recorded net fluid output had a weaker correlation (r=0.66; P<0.001) and lesser ability to predict poor natriuretic response (area under the curve =0.76, 95% confidence interval 0.63-0.89; P=0.002).

CONCLUSIONS

In patients being treated for acute decompensated heart failure, poor natriuretic response can be predicted soon after diuretic administration with excellent accuracy using a spot urine sample.

Decongestion: Diuretics and other therapies for hospitalized heart failure

Acute heart failure (AHF) is a potentially life-threatening clinical syndrome, usually requiring hospital admission. Often the syndrome is characterized by congestion, and is associated with long hospital admissions and high risk of readmission and further healthcare expenditure. Despite a limited evidence-base, diuretics remain the first-line treatment for congestion. Loop diuretics are typically the first-line diuretic strategy with some evidence that initial treatment with continuous infusion or boluses of high-dose loop diuretic is superior to an initial lower dose strategy. In patients who have impaired responsiveness to diuretics, the addition of an oral thiazide or thiazide-like diuretic to induce sequential nephron blockade can be beneficial. The use of intravenous low-dose dopamine is no longer supported in heart failure patients with preserved systolic blood pressure and its use to assist diuresis in patients with low systolic blood pressures requires further study. Mechanical ultrafiltration has been used to treat patients with heart failure and fluid retention, but the evidence-base is not robust, and its place in clinical practice is yet to be established. Several novel pharmacological agents remain under investigation.

Influence of Titration of Neurohormonal Antagonists and Blood Pressure Reduction on Renal Function and Decongestion in Decompensated Heart Failure

BACKGROUND

Reduction in systolic blood pressure (SBP reduction) during the treatment of acute decompensated heart failure is strongly and independently associated with worsening renal function. Our objective was to determine whether SBP reduction or titration of oral neurohormonal antagonists during acute decompensated heart failure treatment negatively influences diuresis and decongestion.

METHODS AND RESULTS

SBP reduction was evaluated from admission to discharge in consecutive acute decompensated heart failure admissions (n=656). Diuresis and decongestion were examined across a range of parameters, such as diuretic efficiency, fluid output, hemoconcentration, and diuretic dose. The average reduction in SBP was 14.4 ± 19.4 mm Hg, and 77.6% of the population had discharge SBP lower than admission. SBP reduction was strongly associated with worsening renal function (odds ratio, 1.9; 95% confidence interval, 1.2-2.9; P=0.004), a finding that persisted after adjusting for parameters of diuresis and decongestion (odds ratio, 2.0; 95% confidence interval, 1.3-3.2; P=0.002). However, SBP reduction did not negatively affect diuresis or decongestion (P ≥ 0.25 for all parameters). Uptitration of neurohormonal antagonists occurred in >50% of admissions and was associated with a modest additional reduction in blood pressure (≤ 5.6 mm Hg). Notably, worsening renal function was not increased, and diuretic efficiency was significantly improved with the uptitration of neurohormonal antagonists.

CONCLUSIONS

Despite a higher rate of worsening renal function, blood pressure reduction was not associated with worsening of diuresis or decongestion. Furthermore, titration of oral neurohormonal antagonists was actually associated with improved diuresis in this cohort. These results provide reassurance that the guideline-recommended titration of chronic oral medication during acute decompensated heart failure hospitalization may not be antagonistic to the short-term goal of decongestion.

Clinical Use of Diuretics in Heart Failure, Cirrhosis, and Nephrotic Syndrome

Diuretics play significant role in pharmacology and treatment options in medicine. This paper aims to review and evaluate the clinical use of diuretics in conditions that lead to fluid overload in the body such as cardiac failure, cirrhosis, and nephrotic syndrome. To know the principles of treatment it is essential to understand the underlying pathophysiological mechanisms that cause the need of diuresis in the human body. Various classes of diuretics exist, each having a unique mode of action. A systemic approach for management is recommended based on the current guidelines, starting from thiazides and proceeding to loop diuretics. The first condition for discussion in the paper is cardiac failure. Treatment of ascites in liver cirrhosis with spironolactone as the primary agent is highlighted with further therapeutic options. Lastly, management choices for nephrotic syndrome are discussed and recommended beginning from basic sodium restriction to combined diuretic therapies. Major side effects are discussed.

A reappraisal of loop diuretic choice in heart failure patients

The health and economic burden of heart failure is significant and continues to grow each year. Loop diuretics are an integral part of symptom management in heart failure. Furosemide is used disproportionately compared with other loop diuretics, and there is currently no guidance for physicians regarding which agent to choose. However, there exist pharmacologic differences as well as other mechanistic differences that appear to favor torsemide use over furosemide. Compared with furosemide, torsemide improves surrogate markers of heart failure severity such as left ventricular function, plasma brain natriuretic peptide levels, and New York Heart Association functional class and may also reduce hospitalizations, readmissions, and mortality. Data suggest that these benefits could be mediated through torsemide's ability to positively affect the renin-angiotensin-aldosterone system. Specifically, torsemide has been shown to inhibit aldosterone secretion, synthesis, and receptor binding in vitro, as well as decrease transcardiac extraction of aldosterone, myocardial collagen production, and cardiac fibrosis in patients with heart failure. We identified pertinent literature using keyword MEDLINE searches and cross-referencing prior bibliographies. We summarize the available data suggesting potential benefits with torsemide over furosemide, and call attention to the need for a reappraisal of diuretic use in heart failure patients and also for a well-powered, randomized control trial assessing torsemide versus furosemide use.

Diuretic response in acute heart failure-pathophysiology, evaluation, and therapy

The administration of loop diuretics to achieve decongestion is the cornerstone of therapy for acute heart failure. Unfortunately, impaired response to diuretics is common in these patients and associated with adverse outcomes. Diuretic resistance is thought to result from a complex interplay between cardiac and renal dysfunction, and specific renal adaptation and escape mechanisms, such as neurohormonal activation and the braking phenomenon. However, our understanding of diuretic response in patients with acute heart failure is still limited and a uniform definition is lacking. Three objective methods to evaluate diuretic response have been introduced, which all suggest that diuretic response should be determined based on the effect of diuretic dose administered. Several strategies have been proposed to overcome diuretic resistance, including combination therapy and ultrafiltration, but prospective studies in patients who are truly unresponsive to diuretics are lacking. An enhanced understanding of diuretic response should ultimately lead to an improved, individualized approach to treating patients with acute heart failure.

A combined-biomarker approach to clinical phenotyping renal dysfunction in heart failure

BACKGROUND

Differentiating heart failure (HF) induced renal dysfunction (RD) from intrinsic kidney disease is challenging. It has been demonstrated that biomarkers such as B-type natriuretic peptide (BNP) or the blood urea nitrogen to creatinine ratio (BUN/creat) can identify high- vs low-risk RD. Our objective was to determine if combining these biomarkers could further improve risk stratification and clinical phenotyping of patients with RD and HF.

METHODS AND RESULTS

A total of 908 patients with a discharge diagnosis of HF were included. Median values were used to define elevated BNP (>1296 pg/mL) and BUN/creat (>17). In the group without RD, survival was similar regardless of BNP and BUN/creat (n = 430, adjusted P = .52). Similarly, in patients with both a low BNP and BUN/creat, RD was not associated with mortality (n = 250, adjusted hazard ratio [HR] = 1.0, 95% confidence interval [CI] 0.6-1.6, P = .99). However, in patients with both an elevated BNP and BUN/creat those with RD had a cardiorenal profile characterized by venous congestion, diuretic resistance, hypotension, hyponatremia, longer length of stay, greater inotrope use, and substantially worse survival compared with patients without RD (n = 249, adjusted HR = 1.8, 95% CI 1.2-2.7, P = .008, P interaction = .005).

CONCLUSIONS

In the setting of decompensated HF, the combined use of BNP and BUN/creat stratifies patients with RD into groups with significantly different clinical phenotypes and prognosis.

Loop diuretic efficiency: a metric of diuretic responsiveness with prognostic importance in acute decompensated heart failure

BACKGROUND

Rather than the absolute dose of diuretic or urine output, the primary signal of interest when evaluating diuretic responsiveness is the efficiency with which the kidneys can produce urine after a given dose of diuretic. As a result, we hypothesized that a metric of diuretic efficiency (DE) would capture distinct prognostic information beyond that of raw fluid output or diuretic dose.

METHODS AND RESULTS

We independently analyzed 2 cohorts: (1) consecutive admissions at the University of Pennsylvania (Penn) with a primary discharge diagnosis of heart failure (n=657) and (2) patients in the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) data set (n=390). DE was estimated as the net fluid output produced per 40 mg of furosemide equivalents, then dichotomized into high versus low DE based on the median value. There was only a moderate correlation between DE and both intravenous diuretic dose and net fluid output (r(2)≤0.26 for all comparisons), indicating that DE was describing unique information. With the exception of metrics of renal function and preadmission diuretic therapy, traditional baseline characteristics, including right heart catheterization variables, were not consistently associated with DE. Low DE was associated with worsened survival even after adjusting for in-hospital diuretic dose, fluid output, in addition to baseline characteristics (Penn: hazards ratio [HR], 1.36; 95% confidence interval [CI], 1.04-1.78; P=0.02; ESCAPE: HR, 2.86; 95% CI, 1.53-5.36; P=0.001).

CONCLUSIONS

Although in need of validation in less-selected populations, low DE during decongestive therapy portends poorer long-term outcomes above and beyond traditional prognostic factors in patients hospitalized with decompensated heart failure.

A meta-analysis of continuous vs intermittent infusion of loop diuretics in hospitalized patients

BACKGROUND

Several studies have examined the potential benefits of continuous vs intermittent (bolus) intravenous loop diuretic administration in hospitalized patients with conflicting results. We conducted a meta-analysis to compare the efficacy of these 2 strategies in hospitalized adults and children with extracellular fluid volume expansion.

METHODS

We searched MEDLINE (through October 2012) and prior meta-analyses for randomized controlled trials comparing the efficacy of continuous vs intermittent infusion of loop diuretics. Random-effects model meta-analyses were performed to examine several outcomes, including net change in urine output and body weight.

RESULTS

We identified 7 crossover and 11 parallel-arm randomized controlled trials (936 patients) of adults and children. In the 15 studies of adults, continuous loop diuretic infusion resulted in a nonsignificant net increase in daily urine output of 334 mL (95% confidence interval [CI], -74 to 742; P = .11) relative to the bolus infusion. In the 8 studies that used a loading dose, continuous loop diuretic infusion resulted in a significant net increase in daily urine output of 294 mL (95% CI, 31-557; P = .03) relative to the intermittent infusion. There was also a significant net decrease in body weight of 0.78 kg (95% CI, -1.54 to -0.03; P = .04) in the continuous relative to the intermittent loop diuretic infusion. In the 3 studies of children, there was no demonstrable effect on daily urine output or body weight.

CONCLUSION

Continuous infusion of loop diuretics preceded by a loading dose results in greater diuresis in hospitalized adults with extracellular fluid volume expansion compared with intermittent dosing regimens. Further studies are required to examine whether these benefits translate into improved clinical outcomes.

A retrospective evaluation of the efficacy of intravenous bumetanide and comparison of potency with furosemide

BACKGROUND

The potency of intravenous bumetanide to furosemide using a ratio of 1:40 has been suggested; however, there are little data supporting this ratio. Recent drug shortages required the use of bumetanide in a large patient population, enabling further characterization of the efficacy of IV bumetanide.

OBJECTIVE

The primary objective of this study was to estimate a dose-response effect of IV bumetanide on urine output (UOP) in all patients that received 48 hours of therapy as well as in a subgroup of patients with heart failure (HF). This subgroup was used to compare the potency of bumetanide with furosemide. A secondary safety objective described electrolyte replacement required during therapy.

METHODS

This was a single-center retrospective study examining the dose-response effect of IV bumetanide in patients receiving at least 48 hours of intermittent (iIV) or continuous (cIV) dosing, measured by UOP per mg of drug received (mL/mg). The potency of IV bumetanide was compared with furosemide in a subset of patients with HF using pre-existing data. The safety of IV bumetanide was analyzed by quantifying electrolyte replacement received during the study period.

RESULTS

The primary outcome was higher in the iIV group (n=93) at 1273 ± 844 mL/mg compared with the cIV group (n=16) at 749 ± 370 mL/mg (P=0.002). Among patients with HF who received furosemide (iIV n=30, cIV n=26) or bumetanide (iIV n=30, cIV n=3), a potency ratio of 41:1 was found for the iIV group and 34:1 for all patients with HF. There was no significant difference in electrolyte replacement between groups.

CONCLUSIONS

A greater response was seen with intermittent bumetanide compared with continuous infusion bumetanide. This study supports the 40:1 dose equivalence ratio (furosemide:bumetanide) in patients with HF receiving at least 48 hours of intravenous intermittent bumetanide.

Should torsemide be the loop diuretic of choice in systolic heart failure?

Furosemide is the most widely prescribed loop diuretic in the setting of systolic heart failure (HF), yet torsemide has been shown to have less inter- and intra-individual variation in bioavailability and a longer duration of action compared with furosemide. Thus, a systematic review and meta-analysis of randomized controlled trials comparing torsemide versus furosemide in patients with systolic HF using OVID MEDLINE, Excerpta Medica (Embase), Web of Science, PubMed and Google Scholar was performed. Extracted data included study design, sample characteristics, intervention, outcomes and control for potential confounding factors. A DerSimonian and Laird random-effects model was used to compute summary risk ratios for HF and cardiovascular (CV) readmission outcomes. Two randomized trials comparing furosemide with torsemide in 471 patients with systolic HF were identified. Compared to furosemide, torsemide significantly reduced total HF readmissions (relative risk [RR]: 0.41, 95% CI: 0.28–0.61, p < 0.0001) and HF readmissions (RR: 0.53, 95% CI: 0.33–0.84, p = 0.008) as well as CV readmissions (RR: 0.77, 95% CI: 0.60–0.98, p = 0.03) in patients with “at least 1 readmission.” Moreover, compared with furosemide, torsemide caused a 14% reduction in all-cause mortality (RR: 0.86 [0.53–1.39], p = 0.54). Compared with furosemide, torsemide significantly reduces HF and CV-related hospital readmissions in systolic HF. Furthermore, torsemide is associated with a trend in reducing all-cause mortality.

Flip-flop pharmacokinetics--delivering a reversal of disposition: challenges and opportunities during drug development

Flip-flop pharmacokinetics is a phenomenon often encountered with extravascularly administered drugs. Occurrence of flip-flop spans preclinical to human studies. The purpose of this article is to analyze both the pharmacokinetic interpretation errors and opportunities underlying the presence of flip-flop pharmacokinetics during drug development. Flip-flop occurs when the rate of absorption is slower than the rate of elimination. If it is not recognized, it can create difficulties in the acquisition and interpretation of pharmacokinetic parameters. When flip-flop is expected or discovered, a longer duration of sampling may be necessary in order to avoid overestimation of fraction of dose absorbed. Common culprits of flip-flop disposition are modified dosage formulations; however, formulation characteristics such as the drug chemical entities themselves or the incorporated excipients can also cause the phenomenon. Yet another contributing factor is the physiological makeup of the extravascular site of administration. In this article, these causes of flip-flop pharmacokinetics are discussed with incorporation of relevant examples and the implications for drug development outlined.

Update in diuretic therapy: clinical pharmacology

All diuretics except spironolactone exert their effects from the lumen of the nephron. Thus, to exert an effect, they must reach the urine. Pharmacokinetics (PK) describes this access. Different edematous disorders can affect access to this site of action and therein affect response to a diuretic. In addition, once a diuretic reaches the site of action, a response ensues. The characteristics of this response that can be affected by a patient's clinical condition are described by the pharmacodynamics (PD) of a diuretic. To understand the mechanisms of abnormal response to a diuretic one must dissect its PK and PD in different edematous disorders. For example, in patients with renal insufficiency, the mechanism of poor diuretic response is PK. In contrast, in patients with cirrhosis or in those with congestive heart failure, it is PD. In patients with nephrotic syndrome, both PK and PD are operative. These different mechanisms mandate differences in therapeutic strategy, as explained in this article.