What are the 2024 American Heart Association (AHA)/American College of Cardiology (ACC) guidelines for perioperative transfusion thresholds?

2024 AHA/ACC Guidelines for Perioperative Transfusion

For most perioperative patients, the 2024 AHA/ACC guidelines recommend a restrictive transfusion strategy with a hemoglobin threshold of 7-8 g/dL in hemodynamically stable patients. This approach reduces unnecessary transfusions while maintaining patient safety across most clinical scenarios.

General Transfusion Thresholds

The current guidelines recommend the following transfusion thresholds:

• Standard perioperative patients (hemodynamically stable): Transfuse when hemoglobin < 7 g/dL 1
• Cardiac surgery patients: Consider transfusion when hemoglobin < 7.5-8 g/dL 2
• Patients with cardiovascular disease: Consider transfusion when hemoglobin < 8 g/dL 2, 1
• Orthopedic surgery patients: Consider transfusion when hemoglobin < 8 g/dL 1

Patient-Specific Considerations

Cardiac Disease Patients

• Stable cardiovascular disease: Hemoglobin threshold of 8 g/dL 2
• Acute coronary syndrome: No specific recommendation due to insufficient evidence; symptom-guided approach recommended 2
• Post-cardiac surgery: Restrictive transfusion strategy with threshold of 7.5-8 g/dL 2

Symptomatic Patients

Regardless of hemoglobin level, transfusion should be considered in patients with symptoms of anemia such as:

• Chest pain
• Orthostatic hypotension
• Congestive heart failure symptoms
• Signs of inadequate tissue oxygenation 2

Implementation Algorithm

1. Assess baseline risk:

   • Determine if patient has cardiovascular disease, is undergoing cardiac/orthopedic surgery, or has other high-risk features

2. Monitor hemoglobin levels:

   • Obtain baseline hemoglobin
   • Monitor for significant drops during/after surgery

3. Apply appropriate threshold:

   • Standard patients: 7 g/dL
   • Cardiac surgery: 7.5-8 g/dL
   • Cardiovascular disease: 8 g/dL
   • Orthopedic surgery: 8 g/dL

4. Assess for symptoms:

   • If patient develops symptoms of anemia despite hemoglobin above threshold, consider transfusion

5. Transfuse conservatively:

   • Single-unit transfusions followed by reassessment

Evidence Quality and Considerations

The restrictive transfusion strategy is supported by high-quality evidence showing no difference in mortality, myocardial infarction, or other adverse outcomes compared to liberal strategies 2, 1, 3. A 2023 AABB guideline reinforces this approach, noting that restrictive strategies reduce transfusion exposure by approximately 41% without increasing adverse outcomes 1, 3.

However, caution is warranted in certain populations:

• Patients with acute coronary syndrome may benefit from higher thresholds, though definitive evidence is lacking 2
• Vascular surgery patients may have worse outcomes with very restrictive thresholds (< 8 g/dL) 4

Common Pitfalls to Avoid

1. Over-transfusion based on arbitrary thresholds - Avoid transfusing based solely on a hemoglobin number without considering clinical context

2. Ignoring symptoms - Patients with symptoms of anemia may benefit from transfusion regardless of hemoglobin level

3. One-size-fits-all approach - Different surgical populations have different optimal thresholds

4. Failure to reassess - After single-unit transfusion, reassess before giving additional units

5. Neglecting alternatives - Consider iron supplementation, erythropoietin, or other blood conservation strategies when appropriate

The evidence consistently shows that restrictive transfusion strategies are safe for most perioperative patients and reduce unnecessary exposure to blood products and their associated risks.