What are the contraindications to starting a heparin (unfractionated heparin) drip for pulmonary embolism (PE)?

From the Guidelines

Heparin drips should not be initiated for pulmonary embolism in patients with active bleeding, severe thrombocytopenia, history of heparin-induced thrombocytopenia (HIT), or known hypersensitivity to heparin products. The contraindications to starting heparin drip for pulmonary embolism can be summarized as follows:

• Active major bleeding at any site, tissue, or organ 1
• Severe thrombocytopenia (platelet count <50,000/μL) 1
• History of heparin-induced thrombocytopenia (HIT) 1
• Known sensitivity to the agent, heparin, sulfites, benzyl alcohol, or pork products 1
• Recent major surgery, especially neurosurgical or ophthalmologic procedures 1
• Severe uncontrolled hypertension (systolic >200, diastolic >110) 1
• Hemorrhagic stroke 1
• Intracranial or spinal lesions 1 Caution is also warranted in patients with recent trauma, peptic ulcer disease, severe liver or kidney disease, and those on concurrent antiplatelet therapy 1. For patients with these contraindications, alternative anticoagulation strategies such as fondaparinux or placement of an inferior vena cava filter may be considered 1. The rationale behind these contraindications is the significant risk of life-threatening hemorrhage that could outweigh the benefits of anticoagulation. In cases where anticoagulation is absolutely necessary despite relative contraindications, careful monitoring of anti-Xa levels or aPTT, along with close clinical observation for bleeding complications, is essential.

From the FDA Drug Label

The use of Heparin Sodium Injection is contraindicated in patients with the following conditions: • History of heparin-induced thrombocytopenia and heparin-induced thrombocytopenia and thrombosis • Known hypersensitivity to heparin or pork products (e.g., anaphylactoid reactions) • In whom suitable blood coagulation tests, e.g., the whole blood clotting time, partial thromboplastin time, etc., cannot be performed at appropriate intervals • An uncontrolled active bleeding state, except when this is due to disseminated intravascular coagulation.

The contra indications to starting heparin drip for Pulmonary embolism are:

• History of heparin-induced thrombocytopenia and heparin-induced thrombocytopenia and thrombosis
• Known hypersensitivity to heparin or pork products
• Inability to perform suitable blood coagulation tests at appropriate intervals
• Uncontrolled active bleeding state, except when due to disseminated intravascular coagulation 2 2

From the Research

Contra Indications to Starting Heparin Drip for Pulmonary Embolism

• Heparin-induced thrombocytopenia (HIT) is a serious contra indication to starting heparin drip for pulmonary embolism, as it can paradoxically increase the risk of thrombosis while causing a significant reduction in platelet count 3, 4.
• Active bleeding or high risk of bleeding is a contra indication to starting heparin drip, although this is not explicitly stated in the provided studies.
• Severe renal insufficiency is a contra indication to the use of fondaparinux and direct oral anticoagulants (DOACs) in the treatment of heparin-induced thrombocytopenia, and may also be a contra indication to starting heparin drip 4.
• Pregnancy or lactation may be a contra indication to starting heparin drip, although this is not explicitly stated in the provided studies.
• Other contra indications may include a history of heparin allergy, or the presence of other conditions that may increase the risk of bleeding or thrombosis, although these are not explicitly stated in the provided studies.

Special Considerations

• In patients with a history of HIT, alternative anticoagulants such as direct thrombin inhibitors (DTIs) or fondaparinux may be used instead of heparin 3, 4.
• In patients with severe renal insufficiency, alternative anticoagulants that do not require renal clearance may be used instead of heparin or fondaparinux 4.
• Close monitoring of anticoagulation is necessary in patients with pulmonary embolism who are being treated with heparin or other anticoagulants, in order to minimize the risk of bleeding or thrombosis 3, 5.