What are the absolute contraindications for Heparin (unfractionated heparin) or Low Molecular Weight Heparin (LMWH) Deep Vein Thrombosis (DVT) prophylaxis?

Absolute Contraindications for Heparin or LMWH DVT Prophylaxis

The absolute contraindications for heparin (unfractionated heparin) or low molecular weight heparin (LMWH) deep vein thrombosis (DVT) prophylaxis include history of heparin-induced thrombocytopenia (HIT), active major bleeding, hypersensitivity to heparin or pork products, and uncontrolled bleeding states. 1

Absolute Contraindications

• History of heparin-induced thrombocytopenia (HIT) or heparin-induced thrombocytopenia and thrombosis (HITTS) - Due to risk of paradoxical thrombosis 1
• Known hypersensitivity to heparin or pork products - Can cause anaphylactoid reactions 1
• Active major, serious, or potentially life-threatening bleeding not reversible with medical or surgical intervention - Including any active bleeding in critical sites such as intracranial, pericardial, retroperitoneal, intraocular, intra-articular, or intraspinal locations 2
• Uncontrolled bleeding state - Except when due to disseminated intravascular coagulation 1
• Severe, uncontrolled malignant hypertension - Due to increased risk of bleeding complications 2, 3
• Severe, uncompensated coagulopathy (e.g., liver failure) - Increases bleeding risk significantly 2
• Severe platelet dysfunction or inherited bleeding disorder - Compounds anticoagulant effects 2
• Persistent, severe thrombocytopenia (< 20,000/μL) - Significantly increases bleeding risk 2
• Inability to monitor coagulation parameters at appropriate intervals - For full-dose heparin therapy (not typically needed for prophylactic dosing) 1

Relative Contraindications

While not absolute contraindications, the following conditions warrant careful consideration before initiating heparin or LMWH prophylaxis:

• Intracranial or spinal lesions at high risk for bleeding - May increase risk of catastrophic hemorrhage 2
• Active peptic or other GI ulceration at high risk of bleeding - Potential site for significant hemorrhage 2
• Active but non-life-threatening bleeding (e.g., trace hematuria) - May worsen with anticoagulation 2
• Intracranial or CNS bleeding within past 4 weeks - Risk of rebleeding 2
• Major surgery or serious bleeding within past 2 weeks - Increased risk of postoperative bleeding 2
• Persistent thrombocytopenia (< 50,000/μL) - May increase bleeding risk 2
• Hepatic insufficiency with elevated INR (>1.5) - Affects coagulation 3
• Severe renal insufficiency - May affect drug clearance, especially for LMWH 3, 4
• Patients aged 90 years or older with creatinine clearance < 60 mL/min - Specifically for tinzaparin (a type of LMWH) 3

Special Considerations

• Laboratory monitoring should be considered in specific populations when using LMWH: newborns, children, patients with renal impairment, pregnant patients, and those at extremes of body weight (< 40 kg or > 100 kg) 4
• Neuraxial anesthesia - Heparin and LMWH should be used with extreme caution or avoided in patients undergoing spinal anesthesia or lumbar puncture due to risk of epidural hematoma 2, 4
• Mechanical prophylaxis should be used instead of pharmacological prophylaxis when anticoagulation is contraindicated 2, 5

Alternative Approaches

• When heparin is contraindicated, mechanical methods such as intermittent pneumatic compression devices or antiembolism stockings should be used 2
• For patients with a history of HIT requiring anticoagulation, alternative anticoagulants like direct thrombin inhibitors (e.g., argatroban) may be considered 3, 4
• The heparinoid danaparoid sodium has been shown effective for treatment of HIT with minimal cross-reactivity with heparin antibodies 4

Understanding these contraindications is crucial for safe and effective DVT prophylaxis in patients at risk. When absolute contraindications exist, mechanical prophylaxis methods should be employed to reduce VTE risk while avoiding the potential complications of pharmacological anticoagulation.