Heparin Use in Infective Endocarditis: Not Routinely Safe
Routine anticoagulation with heparin is not recommended in patients with infective endocarditis unless a separate indication exists, such as a mechanical prosthetic valve requiring anticoagulation. 1
Primary Recommendation
The American College of Chest Physicians explicitly recommends against routine anticoagulant therapy in patients with infective endocarditis (Grade 1C), unless there is a separate indication for anticoagulation unrelated to the endocarditis itself. 1 This represents the highest level of recommendation strength, indicating clear evidence of harm outweighing benefit.
Specific Clinical Scenarios
Patients with Mechanical Prosthetic Valves Who Develop Endocarditis
- Discontinue warfarin and replace with heparin in patients with prosthetic valves on warfarin who develop endocarditis. 1
- This recommendation is primarily driven by the need for rapid reversibility if urgent surgery becomes necessary, rather than safety concerns about hemorrhagic complications. 1
- The heparin can be easily reversed if emergency valve surgery is required, whereas warfarin effects take days to dissipate. 1
Neurological Complications
If neurological symptoms develop during endocarditis:
- Immediately discontinue all anticoagulation until intracranial hemorrhage is excluded by MRI or CT scanning. 1
- For patients with intracranial hemorrhage, interruption of all anticoagulation is mandatory (Class I recommendation). 1
- For ischemic stroke without hemorrhage, replacement of oral anticoagulants with unfractionated or low molecular weight heparin for 1-2 weeks should be considered under close monitoring (Class IIa). 1
Mechanical Valve Endocarditis with Embolic Stroke
- For patients with mechanical valve endocarditis complicated by embolic stroke, anticoagulation should be discontinued for at least 2 weeks of antibiotic therapy to prevent hemorrhagic conversion (Class IIa, Level of Evidence C). 1
- Heparin should be used with extreme caution in patients with infective endocarditis. 1
Staphylococcus aureus Endocarditis
- In the absence of stroke, replacement of oral anticoagulant therapy by unfractionated or low molecular weight heparin for 1-2 weeks should be considered in cases of S. aureus endocarditis under close monitoring (Class IIa). 1
Key Safety Concerns
Hemorrhagic Risk
The FDA label for heparin specifically warns to use heparin with caution in subacute bacterial endocarditis, listing it as a disease state with increased risk of hemorrhage. 2 Hemorrhage can occur at virtually any site in patients receiving heparin, and fatal hemorrhages have been documented. 2
Altered Heparin Responsiveness
- Patients with stabilized endocarditis demonstrate significantly reduced heparin responsiveness during cardiopulmonary bypass, with lower heparin sensitivity index and higher rates of heparin resistance. 3
- This altered responsiveness is associated with preoperative hypercoagulability and reduced antithrombin III activity. 3
- Patients with endocarditis have distinct coagulation profiles showing concomitant hyper- and hypocoagulability, with increased bleeding complications despite hypercoagulable markers. 4
Important Distinctions
Non-Bacterial Thrombotic Endocarditis (NBTE)
This is a completely different entity where anticoagulation is actually recommended:
- For patients with NBTE and systemic or pulmonary emboli, treatment with full-dose IV unfractionated heparin or subcutaneous low molecular weight heparin is suggested over no anticoagulation (Grade 2C). 1
- Case reports support that heparin should remain the anticoagulation agent of choice in NBTE associated with malignancy. 5
Common Pitfalls to Avoid
Do not confuse infective endocarditis with non-bacterial thrombotic endocarditis - they have opposite anticoagulation recommendations. 1
Do not continue anticoagulation if neurological symptoms develop - always exclude intracranial hemorrhage first. 1
Do not assume heparin will prevent embolic events - the evidence for anticoagulant therapy in endocarditis is based on a low level of evidence, and routine use is not supported. 1
Do not forget to discontinue antiplatelet therapy - aspirin should also be discontinued in patients with endocarditis unless a separate indication exists. 1