What are the contraindications for thromboprophylaxis in a patient?

Contraindications for Thromboprophylaxis

Thromboprophylaxis should be withheld in patients with active major bleeding, severe thrombocytopenia (<25,000-50,000/μL), severe uncontrolled malignant hypertension, severe uncompensated coagulopathy, or active bleeding in critical sites (intracranial, pericardial, retroperitoneal, intraocular, intra-articular, intraspinal). 1, 2

Absolute Contraindications

Active bleeding or high bleeding risk represents the primary absolute contraindication to pharmacologic thromboprophylaxis. 1, 3

• Active major, serious, or potentially life-threatening bleeding not reversible with medical or surgical intervention, including any bleeding in critical sites (intracranial, pericardial, retroperitoneal, intraocular, intra-articular, intraspinal) 1, 2

• Severe, uncontrolled malignant hypertension due to significantly increased risk of bleeding complications 2

• Severe, uncompensated coagulopathy such as liver failure, which dramatically increases bleeding risk 1, 2

• Severe platelet dysfunction or inherited bleeding disorder that compounds anticoagulant effects 1, 2

• Persistent, severe thrombocytopenia (<20,000-25,000/μL) represents an absolute contraindication due to catastrophic bleeding risk 1

• Surgery or invasive procedures including lumbar puncture, spinal anesthesia, and epidural catheter placement require withholding anticoagulation 1, 2

• Severe renal impairment (creatinine clearance <30 mL/min) is an absolute contraindication specifically for fondaparinux 4

• Body weight <50 kg is an absolute contraindication for fondaparinux in VTE prophylaxis 4

• Bacterial endocarditis is an absolute contraindication for fondaparinux 4

Relative Contraindications

Relative contraindications require careful risk-benefit assessment but may allow prophylaxis if thrombotic risk substantially exceeds bleeding risk. 1, 2

• Intracranial or spinal lesions at high risk for bleeding may precipitate catastrophic hemorrhage 1, 2

• Active peptic or other GI ulceration at high risk of bleeding represents a potential site for significant hemorrhage 1, 2

• Active but non-life-threatening bleeding (e.g., trace hematuria) may worsen with anticoagulation 1, 2

• Recent intracranial or CNS bleeding (within past 4 weeks) carries rebleeding risk 1, 2

• Major surgery or serious bleeding within past 2 weeks increases postoperative bleeding risk 1, 2

• Persistent thrombocytopenia (25,000-50,000/μL) requires careful consideration; prophylaxis may be held if platelet count <50,000/μL 1, 2

• Hepatic insufficiency with elevated INR affects baseline coagulation status 2

• Severe renal insufficiency may affect drug clearance, particularly for LMWH 2

Critical Clinical Distinctions

Abnormal coagulation tests (PT/PTT) alone are NOT contraindications to thromboprophylaxis in the absence of active bleeding. 1, 3 This is a common pitfall—elevated PT/PTT without bleeding should not prevent prophylaxis. 1

Mild to moderate thrombocytopenia (>50,000/μL) should not interfere with VTE prevention decisions. 5 Only severe thrombocytopenia (<25,000-50,000/μL) represents a true contraindication. 1

Alternative Strategies When Pharmacologic Prophylaxis Contraindicated

When anticoagulation is contraindicated, mechanical prophylaxis with intermittent pneumatic compression (IPC) or graduated compression stockings should be used instead. 1, 2, 3

• Mechanical methods should NOT be used as monotherapy unless pharmacologic methods are contraindicated due to active bleeding or high bleeding risk 1

• Once bleeding risk decreases, substitute pharmacologic for mechanical thromboprophylaxis 3

• For high bleeding risk patients, use mechanical prophylaxis (IPC preferred over stockings) until bleeding risk resolves 1, 6, 3

Special Population Considerations

Cancer patients with active bleeding or high bleeding risk should receive mechanical prophylaxis until bleeding risk resolves, then transition to pharmacologic prophylaxis. 1, 3

Patients with antiphospholipid antibodies and thrombocytopenia typically have thrombotic tendency rather than bleeding risk—VTE prophylaxis should be considered in high-risk conditions. 5

Neuraxial anesthesia requires extreme caution or avoidance due to epidural hematoma risk. 2