Empagliflozin in Heart Failure: Regional Nephron Sodium Handling Effects.

SIGNIFICANCE STATEMENT: The effect of sodium-glucose cotransporter-2 inhibitors (SGLT2i) on regional tubular sodium handling is poorly understood in humans. In this study, empagliflozin substantially decreased lithium reabsorption in the proximal tubule (PT) (a marker of proximal tubular sodium reabsorption), a magnitude out of proportion to that expected with only inhibition of sodium-glucose cotransporter-2. This finding was not driven by an "osmotic diuretic" effect; however, several parameters changed in a manner consistent with inhibition of the sodium-hydrogen exchanger 3. The large changes in proximal tubular handling were acutely buffered by increased reabsorption in both the loop of Henle and the distal nephron, resulting in the observed modest acute natriuresis with these agents. After 14 days of empagliflozin, natriuresis waned due to increased reabsorption in the PT and/or loop of Henle. These findings confirm in humans that SGLT2i have complex and important effects on renal tubular solute handling. BACKGROUND: The effect of SGLT2i on regional tubular sodium handling is poorly understood in humans but may be important for the cardiorenal benefits. METHODS: This study used a previously reported randomized, placebo-controlled crossover study of empagliflozin 10 mg daily in patients with diabetes and heart failure. Sodium handling in the PT, loop of Henle (loop), and distal nephron was assessed at baseline and day 14 using fractional excretion of lithium (FELi), capturing PT/loop sodium reabsorption. Assessments were made with and without antagonism of sodium reabsorption through the loop using bumetanide. RESULTS: Empagliflozin resulted in a large decrease in sodium reabsorption in the PT (increase in FELi=7.5%±10.6%, P = 0.001), with several observations suggesting inhibition of PT sodium hydrogen exchanger 3. In the absence of renal compensation, this would be expected to result in approximately 40 g of sodium excretion/24 hours with normal kidney function. However, rapid tubular compensation occurred with increased sodium reabsorption both in the loop ( P < 0.001) and distal nephron ( P < 0.001). Inhibition of sodium-glucose cotransporter-2 did not attenuate over 14 days of empagliflozin ( P = 0.14). However, there were significant reductions in FELi ( P = 0.009), fractional excretion of sodium ( P = 0.004), and absolute fractional distal sodium reabsorption ( P = 0.036), indicating that chronic adaptation to SGLT2i results primarily from increased reabsorption in the loop and/or PT. CONCLUSIONS: Empagliflozin caused substantial redistribution of intrarenal sodium delivery and reabsorption, providing mechanistic substrate to explain some of the benefits of this class. Importantly, the large increase in sodium exit from the PT was balanced by distal compensation, consistent with SGLT2i excellent safety profile. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: ClinicalTrials.gov ( NCT03027960 ).

Association of Urine Galectin-3 With Cardiorenal Outcomes in Patients With Heart Failure.

BACKGROUND AND OBJECTIVES: Approaches to distinguishing pathological cardiorenal dysfunction in heart failure (HF) from functional/hemodynamically mediated changes in serum creatinine are needed. We investigated urine galectin-3 as a candidate biomarker of renal fibrosis and a prognostic indicator of cardiorenal dysfunction phenotypes. METHODS: We measured urine galectin-3 in 2 contemporary HF cohorts: the Yale Transitional Care Clinic (YTCC) cohort (n = 132) and the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial (n = 434). We assessed the association of urine galectin-3 with all-cause mortality in both cohorts and the association with an established marker of renal tissue fibrosis, urinary amino-terminal propeptide of type III procollagen (PIIINP) in TOPCAT. RESULTS: In the YTCC cohort, there was significant effect modification between higher urine galectin-3 and lower estimated glomerular filtration rates (eGFRs) (Pinteraction = 0.046), such that low eGFR levels had minimal prognostic importance if urine galectin-3 levels were low, but they were important and indicated high risk if urine galectin-3 levels were high. Similar observations were noted in the TOPCAT study (Pinteraction = 0.002). In TOPCAT, urine galectin-3 also positively correlated with urine PIIINP at both baseline (r = 0.43; P < 0.001) and at 12 months (r = 0.42; P < 0.001). CONCLUSIONS: Urine galectin-3 levels correlated with an established biomarker of renal fibrosis in 2 cohorts and was able to differentiate high- vs low-risk phenotypes of chronic kidney disease in HF. These proof-of-concept results indicate that additional biomarker research to differentiate cardiorenal phenotypes is warranted.

Novel Nebulized Milrinone Formulation for the Treatment of Acute Heart Failure Requiring Inotropic Therapy: A Phase 1 Study.

BACKGROUND: Nonintravenous inotropic-delivery options are needed for patients with inotropic-dependent heart failure (HF) to reduce the costs, infections and thrombotic risks associated with chronic central venous catheters and home infusion services. METHODS: We developed a novel, concentrated formulation of nebulized milrinone for inhalation and evaluated the feasibility, safety and pharmacokinetic profile in a prospective, single-arm, phase I clinical trial. We enrolled 10 patients with stage D HF requiring inotropic therapy during a hospital admission for acute HF. Milrinone 60 mg/4 mL was inhaled via nebulization 3 times daily for 48 hours. The coprimary outcomes were adverse events and pharmacokinetic profiles of inhaled milrinone. Acute changes in hemodynamic parameters were secondary outcomes. RESULTS: A concentrated nebulized milrinone formulation was well tolerated, without hypotensive events, arrhythmias or inhalation-related adverse events requiring discontinuation. Nebulized milrinone produced serum concentrations in the goal therapeutic range with a median plasma milrinone trough concentration of 39 (17-66) ng/mL and a median peak concentration of 207 (134-293) ng/mL. There were no serious adverse events. From baseline to 24 hours, mean pulmonary artery saturation increased (60% ± 7%-65 ± 5%; P = 0.001), and mean cardiac index increased (2.0 ± 0.5 mL/min/1.73m2-2.5 ± 0.1 mL/min/1.73m2; P = 0.001) with nebulized milrinone. CONCLUSIONS: In a proof-of-concept study, a concentrated, nebulized milrinone formulation for inhalation was safe and produced therapeutic serum milrinone concentrations. Nebulized milrinone was associated with improved hemodynamic parameters of cardiac output in a population with advanced HF. These promising results require further investigation in a longer-term trial in patients with inotrope-dependent advanced HF.

Increased Spironolactone Dosing in Acute Heart Failure Alters Potassium Homeostasis but Does not Enhance Decongestion.

BACKGROUND: The ATHENA-HF (Aldosterone Targeted Neurohormonal Combined with Natriuresis Therapy in Heart Failure) clinical trial found no improvements in natriuretic peptide levels or clinical congestion when spironolactone 100 mg/day for 96 hours was used in addition to usual treatment for acute heart failure. METHODS: We performed a post hoc analysis of ATHENA-HF to determine whether spironolactone treatment induced any detectable pharmacodynamic effects and whether patients with potentially greater aldosterone activity experienced additional decongestion. Trial subjects previously treated with spironolactone were excluded. We first examined for changes in renal potassium handling. Using the baseline serum potassium level as a surrogate marker of spironolactone activity, we then divided each treatment arm into tertiles of baseline serum potassium and explored for differences in laboratory and clinical congestion outcomes. RESULTS: Among spironolactone-naïve patients, the change in serum potassium did not differ after 24 hours or 48 hours but was significantly greater with spironolactone treatment compared to placebo at 72 hours (0.23 ± 0.55 vs 0.03 ± 0.60 mEq/L; P = 0.042) and 96 hours (0.32 ± 0.51 vs 0.13 ± 0.72 mEq/L; P = 0.046). Potassium supplementation was similar at treatment start and at 24 hours, but spironolactone-treated patients required substantially less potassium replacement at 48 hours (24% vs 36%; P = 0.048), 72 hours (21% vs 37%; P = 0.013), and 96 hours (11% vs 38%; P < 0.001). When the treatment arms were divided into tertiles of baseline serum potassium, there were no differences in the 96-hour log N-terminal pro-B-type natriuretic peptide levels, net fluid loss, urine output, or dyspnea relief in any of the potassium groups, with no effect modification by treatment exposure. CONCLUSIONS: Spironolactone 100 mg/day for 96 hours in patients receiving intravenous loop diuresis for acute heart failure has no clear added decongestive ability but does meaningfully limit potassium wasting.

Clinical and utilization outcomes with short stay units vs hospital admission for lower risk decompensated heart failure: a systematic review and meta-analysis.

With over 1 million primary heart failure (HF) hospitalizations annually, nearly 80% of patients who present to the emergency department with decompensated HF (DHF) are hospitalized. Short stay units (SSU) present an alternative to hospitalization, yet the effectiveness of the SSU strategy of care is not well known. This study is to determine the effectiveness of a SSU strategy compared with hospitalization in lower-risk patients with DHF. Our primary outcome was a composite of 30-day mortality and re-hospitalization. Key secondary outcomes included 90-day mortality and re-hospitalization, costs, and 30-day days-alive-and-out-of-hospital (DAOOH). This is a systematic review and meta-analysis, following PRISMA guidelines. MEDLINE, EMBASE, CENTRAL, CINAHL, SCOPUS, and Web of Science were searched from inception through February 2024. Either randomized trials or comparative observational studies were included if they compared outcomes between low-risk ED DHF patients admitted to an SSU (defined as an observation unit with expected stay ≤ 48 h) vs. admitted to the hospital. Two authors independently screened all titles and abstracts and then identified full texts for inclusion. Data extraction and risk of bias assessments were performed by two authors in parallel. The primary outcome was a composite of death or readmission within 30 days, reported as relative risk (RR), where a RR < 1 favored the SSU strategy. Secondary outcomes included 90-day mortality and re-hospitalization, costs, and 1-month days-alive-and-out-of-hospital (DAOOH). Of the 467 articles identified by our search strategy, only 3 full text articles were included. In meta-analysis for the primary outcome of 30-day death or readmission, the RR was 0.95 (95% CI = 0.56 to 1.63; I2 = 0%) for patients randomized to SSU vs hospitalization (2 studies, 241 patients). There were only 2 total deaths at 30 days in the 2 studies (total N = 258) which reported 30-day mortality, both in hospitalized patients. Only one study reported 90-day outcomes, showing no significant differences. Costs were lower in the SSU arm from one study, and 30-day DAOOH also favored SSU based on a single randomized trial. Based on very limited evidence, SSU provides similar efficacy for 30-day and 90-day mortality and readmission compared to hospitalization. An SSU strategy appears safe and may be cost effective.

The utility of urine sodium-guided diuresis during acute decompensated heart failure.

Diuresis to achieve decongestion is a central aim of therapy in patients hospitalized for acute decompensated heart failure (ADHF). While multiple approaches have been tried to achieve adequate decongestion rapidly while minimizing adverse effects, no single diuretic strategy has shown superiority, and there is a paucity of data and guidelines to utilize in making these decisions. Observational cohort studies have shown associations between urine sodium excretion and outcomes after hospitalization for ADHF. Urine chemistries (urine sodium ± urine creatinine) may guide diuretic titration during ADHF, and multiple randomized clinical trials have been designed to compare a strategy of urine chemistry-guided diuresis to usual care. This review will summarize current literature for diuretic monitoring and titration strategies, outline evidence gaps, and describe the recently completed and ongoing clinical trials to address these gaps in patients with ADHF with a particular focus on the utility of urine sodium-guided strategies.

Randomized controlled trial of urinE chemiStry guided aCute heArt faiLure treATmEnt (ESCALATE): Rationale and design.

Diuresis to achieve decongestion is a central aim of therapy in patients hospitalized for acute decompensated heart failure (ADHF). While multiple clinical trials have investigated initial diuretic strategies for a designated period of time, there is a paucity of evidence to guide diuretic titration strategies continued until decongestion is achieved. The use of urine chemistries (urine sodium and creatinine) in a natriuretic response prediction equation accurately estimates natriuresis in response to diuretic dosing, but a randomized clinical trial is needed to compare a urine chemistry-guided diuresis strategy with a strategy of usual care. The urinE chemiStry guided aCute heArt faiLure treATmEnt (ESCALATE) trial is designed to test the hypothesis that protocolized diuretic therapy guided by spot urine chemistry through completion of intravenous diuresis will be superior to usual care and improve outcomes over the 14 days following randomization. ESCALATE will randomize and obtain complete data on 450 patients with acute heart failure to a diuretic strategy guided by urine chemistry or a usual care strategy. Key inclusion criteria include an objective measure of hypervolemia with at least 10 pounds of estimated excess volume, and key exclusion criteria include significant valvular stenosis, hypotension, and a chronic need for dialysis. Our primary outcome is days of benefit over the 14 days after randomization. Days of benefit combines patient symptoms captured by global clinical status with clinical state quantifying the need for hospitalization and intravenous diuresis. CLINICAL TRIAL REGISTRATION: NCT04481919.

Changes in the Inferior Vena Cava Are More Sensitive Than Venous Pressure During Fluid Removal: A Proof-of-Concept Study.

BACKGROUND: Congestion is central to the pathophysiology of heart failure (HF); thus, tracking congestion is crucial for the management of patients with HF. In this study we aimed to compare changes in inferior vena cava diameter (IVCD) with venous pressure following manipulation of volume status during ultrafiltration in patients with cardiac dysfunction. METHODS AND RESULTS: Patients with stable hemodialysis and with systolic or diastolic dysfunction were studied. Central venous pressure (CVP) and peripheral venous pressure (PVP) were measured before and after hemodialysis. IVCD and PVP were measured simultaneously just before dialysis, 3 times during dialysis and immediately after dialysis. Changes in IVCD and PVP were compared at each timepoint with ultrafiltration volumes. We analyzed 30 hemodialysis sessions from 20 patients. PVP was validated as a surrogate for CVP. Mean ultrafiltration volume was 2102 ± 667 mL. IVCD discriminated better ultrafiltration volumes ≤ 500 mL or ≤ 750 mL than PVP (AUC 0.80 vs 0.62, and 0.80 vs 0.56, respectively; both P< 0.01). IVCD appeared to track better ultrafiltration volume (P< 0.01) and hemoconcentration (P< 0.05) than PVP. Changes in IVCD were of greater magnitude than those of PVP (average change from predialysis: -58 ± 30% vs -28 ± 21%; P< 0.001). CONCLUSIONS: In patients undergoing ultrafiltration, changes in IVCD tracked changes in volume status better than venous pressure.

Multinephron Segment Diuretic Therapy to Overcome Diuretic Resistance in Acute Heart Failure: A Single-Center Experience.

BACKGROUND: The concept of multinephron segment diuretic therapy (MSDT) has been recommended in severe diuretic resistance with only expert opinion and case-level evidence. The purpose of this study was to investigate the safety and efficacy of MSDT, combining 4 diuretic classes, in acute heart failure (AHF) complicated by diuretic resistance. METHODS AND RESULTS: A retrospective analysis was conducted in patients hospitalized with AHF at a single medical center who received MSDT, including concomitant carbonic anhydrase inhibitor, loop, thiazide, and mineralocorticoid receptor antagonist diuretics. Subjects served as their own controls with efficacy evaluated as urine output and weight change before and after MSDT. Serum chemistries, renal replacement therapies, and in-hospital mortality were evaluated for safety. Patients with severe diuretic resistance before MSDT were analyzed as a subcohort. A total of 167 patients with AHF and diuretic resistance received MSDT. MSDT was associated with increased median 24-hour urine output in the first day of therapy compared with the previous day (2.16 L [0.95-4.14 L] to 3.08 L [1.74-4.86 L], P = .003) in the total cohort and in the Severe diuretic resistance cohort (0.91 L [0.43-1.43 L] to 2.08 L [1.13-3.96 L], P < .001). The median cumulative weight loss at day 7 or discharge was -7.4 kg (-15.3 to -3.4 kg) (P = .02). Neither serum sodium, chloride, potassium, bicarbonate, or creatinine changed significantly relative to baseline (P > .05 for all). CONCLUSIONS: In an AHF cohort with diuretic resistance, MSDT was associated with increased diuresis without changes in serum chemistries or kidney function. Prospective studies of MSDT in AHF and diuretic resistance are warranted.

Compensatory post-diuretic renal sodium reabsorption is not a dominant mechanism of diuretic resistance in acute heart failure.

AIMS: In healthy volunteers, the kidney deploys compensatory post-diuretic sodium reabsorption (CPDSR) following loop diuretic-induced natriuresis, minimizing sodium excretion and producing a neutral sodium balance. CPDSR is extrapolated to non-euvolemic populations as a diuretic resistance mechanism; however, its importance in acute decompensated heart failure (ADHF) is unknown. METHODS AND RESULTS: Patients with ADHF in the Mechanisms of Diuretic Resistance cohort receiving intravenous loop diuretics (462 administrations in 285 patients) underwent supervised urine collections entailing an immediate pre-diuretic spot urine sample, then 6-h (diuretic-induced natriuresis period) and 18-h (post-diuretic period) urine collections. The average spot urine sodium concentration immediately prior to diuretic administration [median 15 h (13-17) after last diuretic] was 64 ± 33 mmol/L with only 4% of patients having low (<20 mmol/L) urine sodium consistent with CPDSR. Paradoxically, greater 6-h diuretic-induced natriuresis was associated with larger 18-h post-diuretic spontaneous natriuresis (r = 0.7, P < 0.001). Higher pre-diuretic urine sodium to creatinine ratio (r = 0.37, P < 0.001) was the strongest predictor of post-diuretic spontaneous natriuresis. In a subgroup of patients (n = 43) randomized to protocol-driven intensified diuretic therapies, the mean diuretic-induced natriuresis increased three-fold. In contrast to the substantial decrease in spontaneous natriuresis predicted by CPDSR, no change in post-diuretic spontaneous natriuresis was observed (P = 0.47). CONCLUSION: On a population level, CPDSR was not an important driver of diuretic resistance in hypervolemic ADHF. Contrary to CPDSR, a greater diuretic-induced natriuresis predicted a larger post-diuretic spontaneous natriuresis. Basal sodium avidity, rather than diuretic-induced CPDSR, appears to be the predominant determinate of both diuretic-induced and post-diuretic natriuresis in hypervolemic ADHF.

Efficacy and safety of dapagliflozin in acute heart failure: Rationale and design of the DICTATE-AHF trial.

BACKGROUND: Dapagliflozin, a sodium-glucose cotransporter-2 inhibitor, reduces cardiovascular death and worsening heart failure in patients with chronic heart failure and reduced ejection fraction. Early initiation during an acute heart failure (AHF) hospitalization may facilitate decongestion, improve natriuresis, and facilitate safe transition to a beneficial outpatient therapy for both diabetes and heart failure. OBJECTIVE: The objective is to assess the efficacy and safety of initiating dapagliflozin within the first 24 hours of hospitalization in patients with AHF compared to usual care. METHODS: DICTATE-AHF is a prospective, multicenter, open-label, randomized trial enrolling a planned 240 patients in the United States. Patients with type 2 diabetes hospitalized with hypervolemic AHF and an estimated glomerular filtration rate of at least 30 mL/min/1.73m2 are eligible for participation. Patients are randomly assigned 1:1 to dapagliflozin 10 mg once daily or structured usual care until day 5 or hospital discharge. Both treatment arms receive protocolized diuretic and insulin therapies. The primary endpoint is diuretic response expressed as the cumulative change in weight per cumulative loop diuretic dose in 40 mg intravenous furosemide equivalents. Secondary and exploratory endpoints include inpatient worsening AHF, 30-day hospital readmission for AHF or diabetic reasons, change in NT-proBNP, and measures of natriuresis. Safety endpoints include the incidence of hyper/hypoglycemia, ketoacidosis, worsening kidney function, hypovolemic hypotension, and inpatient mortality. CONCLUSIONS: The DICTATE-AHF trial will establish the efficacy and safety of early initiation of dapagliflozin during AHF across both AHF and diabetic outcomes in patients with diabetes.

Renal negative pressure treatment as a novel therapy for heart failure-induced renal dysfunction.

Congestion is the primary pathophysiological lesion in most heart failure (HF) hospitalizations. Renal congestion increases renal tubular pressure, reducing glomerular filtration rate (GFR) and diuresis. Because each nephron is a fluid-filled column, renal negative pressure therapy (rNPT) applied to the urinary collecting system should reduce tubular pressure, potentially improving kidney function. We evaluated the renal response to rNPT in congestive HF. Ten anesthetized ∼80-kg pigs underwent instrumentation with bilateral renal pelvic JuxtaFlow catheters. GFR was determined by iothalamate clearance (mGFR) and renal plasma flow (RPF) by para-aminohippurate clearance. Each animal served as its own control with randomization of left versus right kidney to -30 mmHg rNPT or no rNPT. mGFR and RPF were measured simultaneously from the rNPT and no rNPT kidney. Congestive HF was induced via cardiac tamponade maintaining central venous pressure at 20-22.5 mmHg throughout the experiment. Before HF induction, rNPT increased natriuresis, diuresis, and mGFR compared with the control kidney (P < 0.001 for all). Natriuresis, diuresis, and mGFR decreased following HF (P < 0.001 for all) but were higher in rNPT kidney versus control (P < 0.001 for all). RPF decreased during HF (P < 0.001) without significant differences between rNPT treatments. During HF, the rNPT kidney had similar diuresis and natriuresis (P > 0.5 for both) and higher fractional excretion of sodium (P = 0.001) compared with the non-rNPT kidney in the no HF period. In conclusion, rNPT resulted in significantly increased diuresis, natriuresis, and mGFR, with or without experimental HF. rNPT improved key renal parameters of the congested cardiorenal phenotype.

Statin-induced rhabdomyolysis from azithromycin interaction in a patient with heterozygous SLCO1B1 polymorphism.

WHAT IS KNOWN AND OBJECTIVE: Unlike other macrolide antibiotics, azithromycin is considered safe to co-prescribe with simvastatin. We aim to elucidate the mechanism of a rare azithromycin-simvastatin interaction. CASE DESCRIPTION: We report a case of simvastatin-induced rhabdomyolysis caused by an azithromycin drug interaction in a patient with heterozygous SLCO1B1 loss-of-function polymorphism. We propose a dual-hit mechanism for this drug-drug-genome interaction. Azithromycin mildly inhibits simvastatin's CYP 3A4 hepatic metabolism, and the SLCO1B1 polymorphism reduces simvastatin hepatic uptake. The combination increases simvastatin serum concentrations significantly, inducing rhabdomyolysis. WHAT IS NEW AND CONCLUSION: Patients with statin-induced myopathy associated with non-classic CYP inhibitors should be considered for genetic testing and alternative statins with less risk of future interactions.

Body mass index and all-cause readmissions following acute heart failure hospitalization.

BACKGROUND/OBJECTIVES: Obesity is associated with a lower mortality risk among patients with heart failure (HF). Whether this obesity paradox applies to all-cause hospitalizations is unknown. We aimed to investigate the association between body mass index (BMI) and 30-day all-cause readmissions following HF hospitalization. SUBJECTS/METHODS: We retrospectively evaluated 2252 HF hospital admissions of Centers of Medicare Services beneficiaries from an academic medical center. We classified obesity using established BMI categories. All 30-day postdischarge readmission to all hospitals and mortality events were documented. We evaluated 30-day postdischarge unplanned, all-cause readmission and death in the total cohort, propensity-matched cohort, and by ejection fraction (EF). RESULTS: An Overweight-Obese BMI (BMI ≥ 25 kg/m2) was paradoxically associated with a lower mortality rate than a Normal BMI (18.5-24.9 kg/m2) (5.0% vs 8.5%, p = 0.0018). In contrast, an Overweight-Obese BMI was associated with a 29% (95% CI: 1.03-1.63) increased relative risk of all-cause readmission compared with a Normal BMI (23.2% vs 18.9%, p = 0.0288), which was consistent across obesity severity subgroups. Among 966 matched admissions, an Overweight-Obese BMI retained higher readmission risk compared with a Normal BMI (25.1% vs 17.2%, p = 0.003). After matching, readmissions remained higher for Overweight-Obese vs Normal BMI in admissions with reduced EF (25.7% vs 17.8%, p = 0.032) and preserved EF (23.0% vs 15.0%, p = 0.048). No difference in the percentage of readmissions for HF (40%) or noncardiovascular causes (45%) existed between Overweight-Obese and Normal BMI groups. CONCLUSIONS: Despite a lower mortality risk, increased BMI is associated with increased all-cause hospital readmission rates in an elderly HF population which persists after propensity matching.

Virtual Visits for Care of Patients with Heart Failure in the Era of COVID-19: A Statement from the Heart Failure Society of America.

In response to the COVID-19 pandemic, US federal and state governments have implemented wide-ranging stay-at-home recommendations as a means to reduce spread of infection. As a consequence, many US healthcare systems and practices have curtailed ambulatory clinic visits-pillars of care for patients with heart failure (HF). In this context, synchronous audio/video interactions, also known as virtual visits (VVs), have emerged as an innovative and necessary alternative. This scientific statement outlines the benefits and challenges of VVs, enumerates changes in policy and reimbursement that have increased the feasibility of VVs during the COVID-19 era, describes platforms and models of care for VVs, and provides a vision for the future of VVs.

Effect of Loop Diuretics on the Fractional Excretion of Urea in Decompensated Heart Failure.

BACKGROUND: Fractional excretion of urea (FEUrea) is often used to understand the etiology of acute kidney injury (AKI) in patients receiving diuretics. Although FEUrea demonstrates diagnostic superiority over fractional excretion of sodium (FENa), clinicians often assume FEUrea is not affected by diuretics. OBJECTIVE: To assess the intravenous loop diuretic effect on FEUrea. METHODS: We analyzed a prospective cohort (n=297) hospitalized with hypervolemic heart failure at Yale New Haven Hospital System. FENa and FEUrea were calculated at baseline and serially after diuretics. The change in FEUrea at peak diuresis was compared with the pre-diuretic baseline. RESULTS: Mean baseline FEUrea was 35.2% ± 10.5% and increased by a mean 5.6% ± 10.5% following 80 mg (40-160 mg) of furosemide equivalents (P < .001). The magnitude of change in FEUrea was clinically important as the distribution of change in FEUrea was similar to the overall distribution of baseline FEUrea. Change in FEUrea was related to the diuretic response (r = 0.61, P < .001), with a larger FEUrea increase in diuretic responders (8.8%, interquartile range [IQR]: 1.8-16.9) than non-responders (1.2%, IQR: -3.2 to 5.5; P < .001). Diuretic administration reclassified 27% of patients between low and high FEUrea groups across a 35% threshold. Neither change in FEUrea nor percentage reclassified out of a low FEUrea category differed between patients with and without AKI (P > .63 for both). CONCLUSIONS: FEUrea is meaningfully affected by loop diuretics. The degree of change in FEUrea is highly variable between patients and commonly of a magnitude that could reclassify across categories of FEUrea.

Loop diuretic resistance complicating acute heart failure.

Acute heart failure hospitalizations complicated by diuretic resistance are associated with worse outcomes. Yet, quantification of the frequency and accompanying risk from loop diuretic resistance is limited by the absence of a comprehensive definition with universal clinical application. Herein, we outline limitations of the current metrics used to identify and define diuretic resistance. We discuss the best available methods to identify and prognosticate outcomes in diuretic resistance. We propose a mechanism-based classification system of diuretic resistance by anatomical location as follows: pre-nephron resistance, pre-loop of Henle resistance, loop of Henle resistance, and post-loop of Henle resistance. Within this paradigm, we compare and contrast historical beliefs of resistance mechanisms with current literature specific to patients with heart failure. We recommend a treatment pathway to restore diuretic efficacy with a literature review of the various combination diuretic strategies and ongoing clinical trials that may impact current best practices.