What are the contraindications to pharmacologic deep‑vein thrombosis prophylaxis in acutely admitted patients?

Contraindications to Pharmacologic DVT Prophylaxis in Acute Admissions

Active bleeding or high risk for major bleeding are the primary contraindications to pharmacologic DVT prophylaxis in acutely admitted patients, and mechanical prophylaxis with graduated compression stockings or intermittent pneumatic compression should be used instead until bleeding risk decreases. 1, 2, 3

Absolute Contraindications

Active bleeding is the most critical contraindication to anticoagulant thromboprophylaxis. 1, 4, 3 The American College of Chest Physicians explicitly recommends against pharmacologic prophylaxis in patients who are actively bleeding, regardless of their thrombotic risk. 1, 3

Severe thrombocytopenia (platelet count <50,000/μL) represents an absolute contraindication to pharmacologic prophylaxis. 4

Relative Contraindications (High Bleeding Risk Situations)

The following conditions constitute high bleeding risk and warrant avoidance of pharmacologic prophylaxis: 1

• Active, uncontrollable bleeding 1
• Recent central nervous system hemorrhage or active cerebrovascular bleeding 1
• Intracranial or spinal lesions at high risk for bleeding (dissecting or cerebral aneurysm) 1
• Recent major surgery at high risk for bleeding 1
• Active peptic ulcer disease or gastrointestinal ulceration 1
• Bacterial endocarditis or pericarditis 1
• Severe, uncontrolled, or malignant hypertension 1
• Severe head trauma 1
• Heparin-induced thrombocytopenia (HIT) 1
• Epidural catheter placement or recent spinal anesthesia/lumbar puncture 1, 2
• Underlying coagulopathy with clotting factor abnormalities or prolonged PT/aPTT (though abnormal coagulation tests alone without active bleeding are not absolute contraindications) 1, 3
• Severe platelet dysfunction 1
• Chronic, clinically significant measurable bleeding (>48 hours or requiring >2 units transfused in 24 hours) 1

Alternative Strategy: Mechanical Prophylaxis

When pharmacologic prophylaxis is contraindicated, the American College of Chest Physicians recommends mechanical thromboprophylaxis with graduated compression stockings (GCS) or intermittent pneumatic compression (IPC) as the alternative approach. 1, 2, 4, 3 This applies to both medical and critically ill patients. 1

Once bleeding risk decreases and thrombotic risk persists, substitute pharmacologic for mechanical prophylaxis. 2, 3 This transition should occur as soon as it is safe to do so, as mechanical prophylaxis alone is less effective than combined or pharmacologic approaches. 1

Special Population Considerations

Cancer patients with active bleeding or high bleeding risk should receive mechanical prophylaxis only until bleeding risk resolves. 1, 3 The same contraindications apply to hospitalized cancer patients as to general medical patients. 1, 3

Critically ill patients who are bleeding or at high risk for major bleeding should use mechanical thromboprophylaxis with GCS and/or IPC at least until the bleeding risk decreases. 1

Patients with lower gastrointestinal bleeding should delay pharmacologic prophylaxis for at least 24 hours after ICU admission, as early heparin administration increases transfusion requirements and ICU length of stay. 5

Patients with spontaneous intracerebral hemorrhage require careful timing—intermittent pneumatic compression should begin at hospital admission, but pharmacologic prophylaxis should be delayed until documentation of bleeding cessation (typically 24-48 hours from onset). 6

Critical Clinical Pitfalls

Do not administer anticoagulants too close to neuraxial anesthesia due to the increased risk of spinal hematoma, which can cause permanent paralysis. 2, 4

Do not confuse abnormal coagulation tests with active bleeding—prolonged PT/aPTT alone without clinical bleeding is not an absolute contraindication to thromboprophylaxis. 3

Do not withhold mechanical prophylaxis when pharmacologic prophylaxis is contraindicated—failure to provide any prophylaxis in high-risk patients significantly increases VTE risk. 1, 4

Reassess bleeding risk daily—the goal is to transition from mechanical to pharmacologic prophylaxis as soon as safely possible, as pharmacologic agents are more effective at preventing VTE. 1, 3