The Heparin Controversy
The heparin controversy revolves around studies in which heparin was used inappropriately (albeit retrospectively) and resulted in poor outcomes. A consensus among stroke management providers is that the efficacy of intravenous unfractionated heparin (UFH) has been inadequately tested in patients with defined stroke subtypes and occlusive vascular lesions. In the presence of contraindications to clot removal, UFH may be useful in the treatment of AIS in patients with specific stoke subtypes. These subtypes include cerebral venous thrombosis, large-artery occlusions with a critical stenosis, or cardiac sources of emboli. Unfractionated heparin may be used as a bridge to full therapeutic anticoagulation with warfarin when warfarin is indicated.[58,59] The current AIS guidelines recommend against the use of heparin in patients with AIS regardless of the underlying issue (class III, level A), whereas the American College of Chest Physicians guidelines recommend UFH for patients with AIS of cardioembolic sources.[3,60] When UFH is used in patients with AIS, blood pressure must be managed appropriately to reduce the risk of hemorrhagic transformation. Monitoring for heparin toxicity should include platelet counts for early identification of heparin-induced thrombocytopenia.
One thing remains consistent between the guidelines and stroke management providers: there is no role for therapeutic dosing of low-molecular-weight heparin (LMWH) in the treatment of AIS. A meta-analysis evaluated safety and efficacy data from 10 randomized controlled trials of LMWHs in patients with AIS. Although LMWHs reduced venous thromboembolic events in patients with AIS, the risk of extracranial bleeding did not outweigh the reduction in death or disability. Therefore, the consensus among stroke management providers is that LMWH has no role in the treatment of AIS, but it may be used along with heparin to prevent deep vein thrombosis.
Pharmacotherapy. 2010;30(5):493-514. © 2010 Pharmacotherapy Publications
Cite this: Acute Ischemic Stroke Update - Medscape - May 01, 2010.