What are the initial pharmacological management options for acute heart failure?

Initial Pharmacological Management of Acute Heart Failure

Intravenous loop diuretics are the cornerstone of initial therapy for acute heart failure with congestion, starting with 20-40 mg IV furosemide for diuretic-naïve patients or at least double the home oral dose for those on chronic therapy, with early addition of vasodilators if systolic blood pressure exceeds 90 mmHg. 1

First-Line Therapy: Loop Diuretics

Diuretics should be administered within 60 minutes of presentation and represent the primary treatment for patients with signs of fluid overload and congestion. 2

Dosing Strategy

• For new-onset AHF or patients not on chronic diuretics: Start with 20-40 mg IV furosemide (or 0.5-1 mg bumetanide, 10-20 mg torasemide) 1
• For patients on chronic oral diuretics: Initial IV dose should be at least equivalent to—or preferably 2-2.5 times—the home oral dose 1, 3
• Administration method: Either intermittent boluses or continuous infusion are acceptable, with no mortality difference between strategies 1

Monitoring Diuretic Response

Assess response within the first 2-6 hours to guide dose escalation: 2, 3

• At 2 hours: Spot urinary sodium should be ≥50-70 mmol/L 2, 3
• At 6 hours: Urine output should be ≥100-150 mL/hour 2, 3
• At 24 hours: Target weight loss of 0.5-1.5 kg or total urine output of 3-5 L 3

If targets are not met, double the diuretic dose up to a maximum of 400-600 mg furosemide per day (up to 1000 mg in severe renal impairment). 2 The total furosemide dose should remain <100 mg in the first 6 hours and <240 mg during the first 24 hours. 1, 4

Managing Diuretic Resistance

For inadequate response despite dose escalation, add combination therapy early: 1, 4, 2

• Acetazolamide 500 mg IV once daily is particularly effective when baseline bicarbonate ≥27 mmol/L and remains effective despite renal dysfunction, but limit use to first 3 days to prevent metabolic disturbances 2
• Thiazide diuretics (hydrochlorothiazide 25 mg PO) in combination with loop diuretics for sequential nephron blockade 1, 4
• Aldosterone antagonists (spironolactone or eplerenone 25-50 mg PO) can be added 1
• Combination therapy at lower doses is more effective with fewer side effects than high-dose monotherapy 1, 4

Critical Monitoring During Diuretic Therapy

Regular assessment is mandatory: 1, 4

• Symptoms and clinical status
• Urine output (bladder catheter recommended for accurate monitoring) 1
• Renal function and electrolytes (potassium, sodium)
• Body weight

Common pitfalls to avoid: 1, 4

• Hypokalaemia and hyponatraemia
• Hypovolaemia leading to hypotension when initiating ACE inhibitors/ARBs
• Neurohormonal activation
• Worsening renal function (transient worsening may be acceptable if decongestion improves)

Second-Line Therapy: Vasodilators

IV vasodilators should be considered early for symptomatic relief in patients with SBP >90 mmHg without symptomatic hypotension. 1

Indications and Use

• In hypertensive AHF (SBP >110 mmHg), vasodilators should be considered as initial therapy alongside diuretics to improve symptoms and reduce congestion 1
• Monitor blood pressure frequently during administration 1
• Vasodilators may reduce the need for high-dose diuretic therapy 1
• Not indicated when SBP <90-110 mmHg 1

Available Agents

• Nitroglycerin and isosorbide dinitrate are most commonly used 1
• Nitroprusside may be considered in severe hypertension, though data are limited 1

Inotropic Agents: Reserved for Specific Situations

Inotropic agents are NOT recommended unless the patient is symptomatically hypotensive or hypoperfused, due to safety concerns. 1

When to Consider Inotropes

Short-term IV infusion may be considered only in patients with: 1

• SBP <90 mmHg AND/OR
• Signs of peripheral hypoperfusion with end-organ dysfunction

Important Contraindications

• Do not use if hypotension is due to hypovolemia or other correctable factors 1
• Avoid in patients with adequate blood pressure and perfusion 1

Agent Selection

• Levosimendan or PDE III inhibitors may be considered to reverse beta-blockade effects if contributing to hypoperfusion 1
• Levosimendan is NOT suitable for SBP <85 mmHg or cardiogenic shock unless combined with vasopressors, as it causes vasodilation 1
• Dobutamine and dopamine are alternatives 1

Monitoring Requirements

Mandatory monitoring when using inotropes: 1

• Continuous ECG monitoring for arrhythmias
• Blood pressure monitoring (consider intra-arterial measurement) 1
• Watch for myocardial ischemia
• Monitor for hypotension (especially with levosimendan and PDE III inhibitors) 1

Vasopressors: Last Resort

Norepinephrine (preferred vasopressor) may be considered in cardiogenic shock despite inotrope treatment to increase blood pressure and maintain vital organ perfusion. 1

Adjunctive Therapies

Non-Invasive Ventilation

Start CPAP or PS-PEEP as soon as possible in patients with acute pulmonary edema showing respiratory distress. 1

• CPAP is simpler and feasible in pre-hospital settings 1
• PS-PEEP is preferred on hospital arrival if acidosis, hypercapnia, or COPD history present 1
• Reduces respiratory distress and may decrease intubation rates 1

Oxygen Therapy

• Increase FiO₂ up to 100% if necessary based on SpO₂, but avoid hyperoxia 1

Medications to Use Cautiously or Avoid

Morphine use cannot be routinely recommended despite historical practice: 1

• Associated with higher rates of mechanical ventilation, ICU admission, and death in registry data 1
• May be considered cautiously (2.5-5 mg IV boluses) for severe dyspnea and anxiety, but individualize the decision 1
• Monitor respiration and watch for nausea, hypotension, bradycardia 1

Thromboembolism Prophylaxis

Low molecular weight heparin is recommended in patients not already anticoagulated and without contraindications to reduce risk of deep venous thrombosis and pulmonary embolism. 1

Clinical Profiles and Treatment Algorithms

Treatment should be tailored based on initial presentation: 1

Hypertensive AHF (SBP >140 mmHg)

• Primary therapy: IV vasodilators + diuretics 1

Normotensive Congested AHF (SBP 90-140 mmHg)

• Primary therapy: IV diuretics 1
• Add vasodilators if SBP >90 mmHg 1

Hypotensive AHF (SBP <90 mmHg)

• Avoid diuretics until adequate perfusion restored 1
• Consider inotropes only if signs of hypoperfusion 1
• Add vasopressors if cardiogenic shock 1

Critical Discharge Considerations

Patients should not be discharged while still congested or before guideline-directed medical therapy has been optimized and initiated. 2 Early follow-up within 2 weeks is essential to up-titrate medications to target doses. 2