“Ace in the Hole”: How to Better Diuresis Your Acute Heart Failure Patients

Heart failure (HF) is one of the most common reasons for admission in patients aged 65 years and older, with more than one million hospitalizations per year costing billions in healthcare expenditures. As patients have become increasingly complex, their presentations increase the risk of tipping any one of their comorbidities into an exacerbated state, contributing to increased readmissions. Deneen Marie Spatz, MD, an associate professor of clinical medicine at the Perelman School of Medicine at the University of Pennsylvania in Philadelphia, introduced the audience to the American Heart Association’s evidence-based mortality-risk score, Get with The Guidelines-HF. This score is designed to help hospitalists predict in-hospital, all-cause, HF mortality to guide early cardiology consultation in improving readmission rates. The scoring system can be conceptualized similarly to calculating a MELD, or Model for End-Stage Liver Disease, score for patients with cirrhosis, with higher scores prompting consultation and referral. The calculator is available at MdCalc.com.  

When evaluating patients with HF for appropriate, guideline-directed medical therapy, it is important to consider their HF stage (A through D) and assess symptoms using the New York Heart Association functional classification (scored I-IV). Additionally, in 2022, the American Heart Association/American College of Cardiology/Heart Failure Society of America (AHA/ACC/HFSA) updated nomenclature utilizing ejection fraction (EF) to better classify patients (see Table 1). It is important to note that the rising obesity epidemic has contributed to 50% of decompensated HF presentations having preserved EF. Regardless of EF, patients with acute HF require first-line therapy with IV diuretics.

Dr. Spatz introduced a newer concept of “door-to-diuretic time,” aimed at treating patients who presented to the emergency department with IV diuresis within 60 minutes of arrival. REALITY-HF, a prospective trial, studied this approach, finding early treatment initiation was statistically significant [odds ratio, 0.36; confidence interval, 0.21 to 0.62; P <0.001] for lower in-hospital mortality and did not differ in patients with acute-on-chronic HF versus de novo HF presentations. The aforementioned AHA Get with the Guidelines-HF score was used in the study, and found that those patients with the highest mortality risk scores receiving early diuresis saw the greatest reduction in their in-hospital mortality. Further retrospective studies on door-to-diuretic time not only confirmed a mortality benefit but showed that those who received diuretics within 90 minutes of arrival experienced a statistically significant decrease in length of stay by 1.4 days.

Admission diuretic strategy begins with the use of IV loop diuretics. The DOSE trial found that although twice daily IV dosing was no different from continuous infusion, those who were treated in the higher dose cohort were more likely to be transitioned to oral therapy at 48 hours, had greater fluid loss, improved symptoms, and at 60 days experienced no significant increase in serum creatinine or cystatin C. When considering an agent, prior studies (such as TRANSFORM-HF) compared furosemide and torsemide and found that there is no statistically significant difference; however, the bioavailability of furosemide is reduced, and it carries a higher incidence of hypokalemia. Dose recommendations differ: for de novo heart failure, initial dosing starting at 40 mg IV furosemide or 1mg bumetanide, versus acute-on-chronic heart failure IV dosing of at least twice the home oral dose.

After the first dose of diuretics, Dr. Spatz proposed the approach of using urine sodium as a biomarker towards improved subsequent dosing selection. If the urine sodium is under 50 mmol/L, then the regimen needs to become more aggressive due to a persistent state of congestion and inadequate response.  Strict intake and output, along with weights, are challenging to obtain consistently, which is where urine sodium can be helpful. She suggested that knowing the maximum dosing of diuretics helped to aid in the selection of second and third follow-up doses, and that ideally, diuresis should be reserved for waking hours between 6 a.m. and 5 p.m. to aid in maintaining the patients’ circadian rhythm.  The PUSH-AF trial in 2023 used a urine sodium of less than 70 mmol/L as a threshold to intensify the diuresis to optimize natriuresis, and the ENACT trial maintained that following urine sodium led to a reduction in length of stay by 1.2 days.

Upon successful intravenous diuresis, transition to orals is required, addressing whether the cause for decompensation was reversible or identifiable so that appropriate measures can be taken to ensure discharge success. Dr. Spatz recommended testing whether the patient has a urinary response within 60 minutes on their home oral dose to assess the appropriateness of therapy prior to discharge. Finally, she recommended creating a rescue dosing plan similar to an asthma action plan, instructing the patient to notify their physician and to take additional dosing of their home oral diuretics should weight gain and heart failure symptoms occur, to prevent re-hospitalization.

For special cases of extreme decompensation when loop diuretic dosing has not proven effective, augmentation agents such as thiazide diuretics or carbonic anhydrase inhibitors, as studied in the Acetazolamide in Decompensated HF with Volume Overload (ADVOR) trial, can improve decongestion without increasing adverse outcomes. Other focus in the literature has surrounded in-hospital titration of sodium-glucose transport protein 2 inhibitors in the DELIVER and EMPEROR-Preserved trials, where lower doses of loop diuretics were required to achieve the same benefits. However, it is important to remain systematic, first trialing loop diuretics, using urine sodium to guide diuresis, and then, if needed, the addition of augmentation agents. Patients should also be active participants in their care, with medication compliance, monitoring of their daily intake and output, and exercising dietary discretion.

Dr. Spaeth is a second-year internal medicine resident at OhioHealth Riverside Methodist Hospital in Columbus, Ohio.