SGLT-2 Inhibitors in Heart Failure: Implications for the Kidneys

Evaluation and Management of Hyponatremia in Heart Failure

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Effect of Acetazolamide as Add-On Diuretic Therapy in Patients With Heart Failure: A Meta-Analysis

The aim of this meta-analysis was to assess the effectiveness of acetazolamide as an add-on diuretic therapy in patients with heart failure. This meta-analysis was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. A systematic literature search was independently performed by two authors using MEDLINE, EMBASE, and the Cochrane Database of Systematic Reviews to identify relevant studies assessing the use of acetazolamide in patients with heart failure. The search keywords included "acetazolamide" and "heart failure". The outcomes assessed in this meta-analysis included natriuresis (mmol/L), diuresis (Liters) and decongestion (absence of signs of volume overload) by 72 hours. Other outcomes assessed in this meta-analysis included hospitalization due to heart failure and all-cause mortality. A total of three studies included a total of 569 heart failure patients. The number of patients achieved decongestion was significantly higher in patients receiving acetazolamide compared to the patients randomized in the control group (RR: 1.34, 95% CI: 1.06-1.67). Compared to patients in the control group, mean natriuresis was significantly higher in acetazolamide patients (MD: 74.91, 95% CI: 39.85-109.97). Diuresis was significantly higher in patients receiving acetazolamide compared to the control group (MD: 0.44, 95% CI: 0.16-0.72). No significant difference was found between the two groups in terms of all-cause mortality and hospitalization due to heart failure. In conclusion, our meta-analysis suggests that acetazolamide may have beneficial impacts on heart failure patients by increasing the number of successful decongestions. Additionally, patients who were treated with acetazolamide had significantly higher natriuresis and diuresis compared to patients in the control group.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

The use of glucagon-like-peptide-1 receptor agonist in the cardiology practice

The presence of type 2 diabetes confronts the patient with an elevated risk to develop atherosclerotic cardiovascular disease (ASCVD), heart failure (HF), or chronic kidney disease (CKD). Glucose control in itself does not prevent these complications in their entirety. More recently several agents within the class of Sodium-Glucose cotransporter 2 inhibitors (SGLT2-I) and Glucagon-like-peptide-1 receptor agonists (GLP-1RA) have emerged as preferred agents to tackle the residual risk of ASCVD, HF, and CKD in patients with type 2 diabetes. Despite compelling trial data and professional society endorsement, the uptake of these agents in clinical practice is low. Especially GLP-1RA is only used in 8% of eligible candidates with type 2 diabetes and <5% of these prescriptions are attributed to cardiologists. This low uptake amongst cardiologists is related to the unfamiliarity with this class, its initiation, and titration, hesitation regarding simultaneous adjustment of other glucose-lowering agents, the unaccustomedness to prescribing injectable agents, and differential medical priorities. This review aims to offer cardiologists a practical tool for the optimal use of a GLP-1RA in their suitable patients and is focussed on the Belgian field of practice.

Association between loop diuretic dose changes and outcomes in chronic heart failure: observations from the ESC-EORP Heart Failure Long-Term Registry

AIMS

Guidelines recommend down-titration of loop diuretics (LD) once euvolaemia is achieved. In outpatients with heart failure (HF), we investigated LD dose changes in daily cardiology practice, agreement with guideline recommendations, predictors of successful LD down-titration and association between dose changes and outcomes.

METHODS AND RESULTS

We included 8130 HF patients from the ESC-EORP Heart Failure Long-Term Registry. Among patients who had dose decreased, successful decrease was defined as the decrease not followed by death, HF hospitalization, New York Heart Association class deterioration, or subsequent increase in LD dose. Mean age was 66 ± 13 years, 71% men, 62% HF with reduced ejection fraction, 19% HF with mid-range ejection fraction, 19% HF with preserved ejection fraction. Median [interquartile range (IQR)] LD dose was 40 (25-80) mg. LD dose was increased in 16%, decreased in 8.3% and unchanged in 76%. Median (IQR) follow-up was 372 (363-419) days. Diuretic dose increase (vs. no change) was associated with HF death [hazard ratio (HR) 1.53, 95% confidence interval (CI) 1.12-2.08; P = 0.008] and nominally with cardiovascular death (HR 1.25, 95% CI 0.96-1.63; P = 0.103). Decrease of diuretic dose (vs. no change) was associated with nominally lower HF (HR 0.59, 95% CI 0.33-1.07; P = 0.083) and cardiovascular mortality (HR 0.62, 95% CI 0.38-1.00; P = 0.052). Among patients who had LD dose decreased, systolic blood pressure [odds ratio (OR) 1.11 per 10 mmHg increase, 95% CI 1.01-1.22; P = 0.032], and absence of (i) sleep apnoea (OR 0.24, 95% CI 0.09-0.69; P = 0.008), (ii) peripheral congestion (OR 0.48, 95% CI 0.29-0.80; P = 0.005), and (iii) moderate/severe mitral regurgitation (OR 0.57, 95% CI 0.37-0.87; P = 0.008) were independently associated with successful decrease.

CONCLUSION

Diuretic dose was unchanged in 76% and decreased in 8.3% of outpatients with chronic HF. LD dose increase was associated with worse outcomes, while the LD dose decrease group showed a trend for better outcomes compared with the no-change group. Higher systolic blood pressure, and absence of (i) sleep apnoea, (ii) peripheral congestion, and (iii) moderate/severe mitral regurgitation were independently associated with successful dose decrease.

Utility of Urine Biomarkers and Electrolytes for the Management of Heart Failure

PURPOSE OF REVIEW

To provide insight into the role of urine biomarkers and electrolytes for the management of heart failure.

RECENT FINDINGS

The age-dependent decrease in glomerular filtration rate due to loss of functional nephrons occurs at a faster pace in heart failure, potentially exacerbated by episodes of acute kidney injury. Urine biomarkers have not convincingly demonstrated to improve detection of irreversible renal damage and predict long-term renal trajectories, compared with serial creatinine measurements. Recent data show that natriuresis and diuretic response track poorly with glomerular filtration, but strongly with prognosis. Urine sodium concentration > 50-70 mmol/L was recently put forward through expert consensus as an adequate diuretic response. The value of urine biomarkers to detect structural renal damage in heart failure remains unsure and the latter is probably uncommon, especially over short-term follow-up. Urine electrolytes on the other hand predict diuretic response accurately and may allow better diuretic titration.

Effects of dapagliflozin on congestion assessed by remote pulmonary artery pressure monitoring

Aims

To explore the effects of dapagliflozin on congestion through CardioMEMS (Abbott Inc., Atlanta, USA) and Cordella™ pulmonary artery Sensor (Endotronix Inc., Lisle, Il, USA) devices, which are implantable systems that provide real‐time remote monitoring of pulmonary artery pressure (PAP).

Methods and results

Single‐centre open label observational pilot trial, to investigate the short‐term effects of dapagliflozin in consecutive heart failure and reduced ejection fraction patients with elevated PAP between October and December 2019, previously implanted with CardioMEMS or Cordella™ Sensor. Changes in PAP were evaluated with an area under the curve methodology to estimate the total sum increase or decrease in pressures (mmHg/day) for 7 days before and after starting dapagliflozin relative to the first day of each period. Nine patients (72 ± 10 years, N‐terminal pro b‐type natriuretic peptide 1027 ± 510 pg/mL, estimated glomerular filtration rate 45 ± 15 mL/kg/m2, left ventricular ejection fraction 35 ± 10%), all on optimal guideline‐directed therapy was included. The mean PAP was reduced from 42 ± 9.16 to 38 ± 9.95 mmHg with dapagliflozin therapy (P < 0.05). The average area under the curve for the week leading to dapagliflozin therapy remained unchanged compared to the drop observed for the week after therapy (P < 0.05). Interestingly, the drop in PAP occurred within the first 2 days of dapagliflozin and remained stable for the week following the start of the therapy.

Conclusions

This is the first study to demonstrate a direct effect of dapagliflozin on achieving effective hemodynamic decongestion, providing further mechanistic data regarding the potential mechanisms of sodium‐glucose co‐transporter‐2 inhibitor benefits on heart failure.

Acetazolamide to increase natriuresis in congestive heart failure at high risk for diuretic resistance

AIMS

To investigate the effects of acetazolamide on natriuresis, decongestion, kidney function and neurohumoral activation in acute heart failure (AHF).

METHODS AND RESULTS

This prospective, two-centre study included 34 AHF patients on loop diuretics with volume overload. All had a serum sodium concentration < 135 mmol/L and/or serum urea/creatinine ratio > 50 and/or an admission serum creatinine increase of > 0.3 mg/dL compared to baseline. Patients were randomised towards acetazolamide 250-500 mg daily plus bumetanide 1-2 mg bid vs. high-dose loop diuretics (bumetanide bid with daily dose twice the oral maintenance dose). The primary endpoint was natriuresis after 24 h. Natriuresis after 24 h was similar in the combinational treatment vs. loop diuretic only arm (264 ± 126 vs. 234 ± 133 mmol; P = 0.515). Loop diuretic efficiency, defined as natriuresis corrected for loop diuretic dose, was higher in the group receiving acetazolamide (84 ± 46 vs. 52 ± 42 mmol/mg bumetanide; P = 0.048). More patients in the combinational treatment arm had an increase in serum creatinine levels > 0.3 mg/dL (P = 0.046). N-terminal pro-B-type natriuretic peptide reduction and peak neurohumoral activation within 72 h were comparable among treatment arms. There was a non-significant trend towards lower all-cause mortality or heart failure readmissions in the group receiving acetazolamide with low-dose loop diuretics vs. high-dose loop diuretic monotherapy (P = 0.098).

CONCLUSION

Addition of acetazolamide increases the natriuretic response to loop diuretics compared to an increase in loop diuretic dose in AHF at high risk for diuretic resistance.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01973335.

Editor's Choice-Diuretic resistance in acute heart failure

Diuretic resistance is a powerful predictor of adverse outcome in acute heart failure (AHF), irrespectively of underlying glomerular filtration rate. Metrics of diuretic efficacy such as natriuresis, urine output, weight loss, net fluid balance, or fractional sodium excretion, differ in their risk for measurement error, convenience, and biological plausibility, which should be taken into account when interpreting their results. Loop diuretic resistance in AHF has multiple causes including altered drug pharmacokinetics, impaired renal perfusion and effective circulatory volume, neurohumoral activation, post-diuretic sodium retention, the braking phenomenon and functional as well as structural adaptations in the nephron. Ideally, these mechanisms should guide specific treatment decisions with the goal of achieving complete decongestion. Therefore, volume overload needs to be identified correctly to avoid poor diuretic response due to electrolyte depletion or dehydration. Next, renal perfusion should be optimised if possible and loop diuretics should be prescribed above their threshold dose. Addition of thiazide-type diuretics should be considered when a progressive decrease in loop diuretic efficacy is observed with prolonged use (i.e., the braking phenomenon). Furthermore, thiazide-type diuretics are a useful addition in patients with low glomerular filtration rate. However, they limit free water excretion and are relatively contraindicated in cases of hypotonic hyponatremia, where acetazolamide is the better option. Finally, ultrafiltration should be considered in patients with refractory diuretic resistance as persistent volume overload after decongestive treatment is associated with worse outcomes. Whether more upfront use of any of these individually tailored decongestion strategies is superior to monotherapy with loop diuretics remains to be shown by adequately powered randomised clinical trials.

Early effects of empagliflozin on exercise tolerance in patients with heart failure: A pilot study

BACKGROUND

Sodium-glucose linked transporter 2 inhibition recently emerged as a promising therapy for reducing the risk of heart failure (HF) in patients with type 2 diabetes mellitus (T2DM). However, there is a lack of data endorsing its role in symptomatic HF patients. We sought to evaluate the short-term effects of empagliflozin on maximal exercise capacity in these patients.

HYPOTHESIS

We postulate tretament with empagliflozin may improve functional capacity in patients with T2DM and established HF.

METHODS

Nineteen T2DM patients with symptomatic HF were prospectively included and underwent cardiopulmonary exercise testing before and 30 days after initiation of empagliflozin therapy. A mixed-effects model for repeated measures was used.

RESULTS

Median patient age was 72 years (interquartile range, 60-79 years); 42.1% were in New York Heart Association class III. Baseline mean (± SD) peak oxygen consumption (peak VO₂ ) was 10.9 ± 4.0 mL/min/kg. Peak VO₂ increased significantly at 30 days (∆: +1.21 [0.66 to 1.76] mL/min/kg; P < 0.001). A significant improvement in ventilatory efficiency during exercise, 6-minute walking distance, and quality of life, and a reduction in antigen carbohydrate 125, were also found. Estimated glomerular filtration rate and natriuretic peptides did not significantly change.

CONCLUSIONS

In this pilot study, empagliflozin was associated with 1-month improvement in exercise capacity in T2DM patients with symptomatic HF. This beneficial effect was also found for other surrogates of severity.