From the Guidelines
Prophylactic anticoagulation should be withheld in thrombocytopenia when platelet counts fall below 25,000/μL due to the significantly increased risk of bleeding complications, as suggested by the guidance from the SSC of the ISTH 1. This threshold is based on the guidance statement that suggests temporarily discontinuing anticoagulation in patients while the platelet count is < 25 × 10^9/L. For patients with acute CAT and severe thrombocytopenia (< 50 × 10^9/L) and a lower risk of thrombus progression, reducing the dose of LMWH to 50% of the therapeutic dose or using a prophylactic dose of LMWH in patients with a platelet count of 25–50 × 10^9/L is recommended 1. Some studies suggest that full-dose anticoagulation is safe when the platelet count is > 50 × 10^9/L 1, but the management among patients who require anticoagulation during periods of severe thrombocytopenia is uncertain. The decision to withhold prophylactic anticoagulation should always be individualized based on the patient's bleeding risk versus thrombotic risk, and patients with active bleeding, recent major hemorrhage, or severe platelet dysfunction (regardless of count) should not receive prophylactic anticoagulation. If anticoagulation is absolutely necessary despite severe thrombocytopenia, platelet transfusions may be considered to maintain counts above the safety threshold while continuing anticoagulation. Key considerations include:
- Platelet count thresholds for withholding anticoagulation
- Individualized decision-making based on bleeding and thrombotic risk
- Use of platelet transfusions to support anticoagulation in severe thrombocytopenia
- Guidance from relevant clinical guidelines, such as those from the SSC of the ISTH 1 and the American Society of Clinical Oncology 1.
From the Research
Prophylactic Anticoagulation in Thrombocytopenia
- Prophylactic anticoagulation is not recommended in patients with thrombocytopenia who are at high risk of bleeding, such as those with platelet counts less than 50 × 10(3) per µL 2.
- In patients with heparin-induced thrombocytopenia (HIT), prophylactic anticoagulation with heparin or low-molecular-weight heparin is contraindicated due to the risk of platelet activation and worsening thrombocytopenia 3.
- Direct oral anticoagulants (DOACs) may be considered as an alternative treatment option in patients with HIT, but their use in thrombocytopenia due to other causes is not well established 3, 4.
- The decision to use prophylactic anticoagulation in patients with thrombocytopenia should be individualized and based on the underlying cause of the thrombocytopenia, the risk of bleeding, and the risk of thrombosis 5, 6.
Specific Conditions
- In patients with severe thrombocytopenia (platelet count less than 10 × 10(3) per µL), prophylactic anticoagulation is generally not recommended due to the high risk of spontaneous bleeding 2.
- In patients with thrombocytopenia due to liver disease, disseminated intravascular coagulation, or other conditions that increase the risk of bleeding, prophylactic anticoagulation should be used with caution and only after careful consideration of the risks and benefits 2, 6.
- In patients with thrombocytopenia due to medications, such as heparin or DOACs, alternative treatments should be considered to minimize the risk of worsening thrombocytopenia 3, 4.