What is the treatment for Disseminated Intravascular Coagulation (DIC) in cardiac surgery?

Treatment of DIC in Cardiac Surgery

In cardiac surgery patients with DIC, immediately treat the underlying surgical cause (bleeding source, infection, or surgical complication) while providing hemostatic support with blood products for active bleeding and prophylactic anticoagulation with heparin once bleeding is controlled. 1, 2

Immediate Management Priorities

1. Address the Underlying Cause

• Identify and treat the surgical trigger: This is the absolute cornerstone of DIC management and takes precedence over all other interventions 3, 2, 4
• Common cardiac surgery triggers include:
  • Massive transfusion and dilutional coagulopathy
  • Cardiopulmonary bypass-related activation
  • Surgical bleeding requiring re-exploration
  • Postoperative infection/sepsis
  • Transfusion reactions 4

2. Hemostatic Support for Active Bleeding

Platelet Transfusion:

• Maintain platelets >50×10⁹/L in patients with active bleeding 3, 2
• In high-risk patients without active bleeding, consider transfusion only if platelets <20×10⁹/L 5, 2
• Avoid prophylactic transfusions based solely on laboratory values 5

Plasma and Fibrinogen Replacement:

• Administer 15-30 mL/kg fresh frozen plasma (FFP) in actively bleeding patients with prolonged PT/aPTT 3, 2
• If fibrinogen remains <1.5 g/L despite FFP, give cryoprecipitate (two units) or fibrinogen concentrate 3, 2
• Critical caveat: Do not base transfusion decisions on laboratory results alone; reserve component therapy for patients with actual bleeding or undergoing invasive procedures 2

3. Anticoagulation Strategy

Heparin is FDA-approved for treatment of DIC and should be considered once bleeding is controlled 1:

• For thrombotic complications: Use therapeutic-dose heparin if arterial/venous thromboembolism, severe purpura fulminans, or vascular skin infarction develops 2, 6
• Unfractionated heparin (UFH) is preferred in cardiac surgery patients due to:
  • Short half-life and easy reversibility with protamine 7, 8
  • High bleeding risk in postoperative setting 7
  • Potential renal dysfunction 8
• Dosing approach: Weight-adjusted doses (e.g., 10 units/kg/h) without necessarily targeting aPTT prolongation of 1.5-2.5× control 2
• Prophylactic anticoagulation: Once bleeding stabilizes, use prophylactic-dose heparin for venous thromboembolism prevention in non-bleeding patients 2, 6

Contraindications to heparin:

• Active uncontrolled bleeding 7
• Platelet count <20×10⁹/L 7, 8
• Hyperfibrinolytic DIC (see below) 7, 8

4. Special Considerations for Cardiac Surgery

Monitoring:

• Serial monitoring of platelet count, PT/aPTT, fibrinogen, and D-dimer is essential 3, 2
• Frequency should be at least daily in acute DIC 8
• Important pitfall: aPTT monitoring of UFH may be unreliable in DIC due to baseline prolongation; consider anti-Xa activity assays instead 7

Hyperfibrinolytic DIC:

• Do NOT use tranexamic acid routinely as it increases thrombotic risk 3, 2
• Tranexamic acid may be considered ONLY if:
  • Therapy-resistant bleeding dominates despite other measures 7, 3
  • Hyperfibrinolysis is confirmed by APTEM testing 3
  • Dosing: 10-15 mg/kg loading dose, then 1-5 mg/kg/hour infusion 3
• Avoid heparin in hyperfibrinolytic DIC 7, 8

Agents NOT Recommended:

• Recombinant Factor VIIa: No randomized trial evidence, significant thrombotic risk 7, 2
• Antithrombin concentrate: No proven benefit on clinical endpoints 2
• Activated protein C: Limited evidence in surgical DIC 2

Algorithmic Approach

1. Identify and treat surgical cause (re-exploration if needed, infection control)
2. If actively bleeding: Transfuse platelets to >50×10⁹/L, give FFP 15-30 mL/kg, add cryoprecipitate if fibrinogen <1.5 g/L
3. Once bleeding controlled: Start prophylactic UFH (unless contraindicated)
4. If thrombosis develops: Escalate to therapeutic-dose UFH
5. Monitor daily: Platelets, PT/aPTT, fibrinogen, D-dimer, clinical bleeding/thrombosis
6. Avoid: Routine tranexamic acid, Factor VIIa, prophylactic transfusions without bleeding

The key pitfall in cardiac surgery DIC is treating laboratory abnormalities rather than clinical bleeding, which leads to unnecessary transfusions and potential fluid overload 5, 2. Abnormal coagulation tests alone should not contraindicate necessary anticoagulation in the absence of active bleeding 7, 8.