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Stroke Anticoagulation and Prophylaxis

Practice Essentials

The role of anticoagulation in the treatment of cerebral ischemia has changed. For many years, it was used routinely in acute ischemic stroke. However, more current studies are helping to refine its role in the acute treatment and prevention of stroke. In addition, several new oral and parenteral anticoagulants are in different stages of clinical trials for use in the prophylaxis of ischemic thromboembolic stroke.

Anticoagulation for acute ischemic stroke

Current data do not support routine use of anticoagulation for acute ischemic stroke. However, anticoagulation continues to be recommended for some specific clinical situations. Indications currently proposed by many experts for early full-dose IV heparin after stroke or transient ischemic attack (TIA) include the following:

Conditions with potential high risk of early cardiogenic reembolization

Symptomatic dissection of the arteries supplying the brain

Symptomatic extracranial or intracranial arteriosclerotic stenosis with crescendo TIAs or early progressive stroke

Basilar artery occlusion before or after intra-arterial pharmacological or mechanical thrombolysis.

Known hypercoagulable states

Cerebral venous sinus thrombosis

Stroke prevention in atrial fibrillation

Oral anticoagulation is the therapy of choice for primary and secondary stroke prevention in patients with atrial fibrillation and any of the known additional risk factors.
Asymptomatic patients younger than 65 years with atrial fibrillation and none of the other risk factors are at a low risk and either should be treated with aspirin or should not be treated at all.

Risk factors for bleeding

Risk factors for bleeding in anticoagulated patients include the following:

Hepatic or renal disease

Ethanol abuse

Malignancy

Old age (>75 years)

Rebleeding

Reduced platelet counts or platelet dysfunction

Hypertension that is uncontrolled

Anemia

Genetic factors

Elevated fall risk

Stroke

Stroke prevention after acute myocardial infarction

Anticoagulation for primary stroke prevention after myocardial infarction (MI) is recommended in patients with the following risk factors
:

Persistent or paroxysmal atrial fibrillation

Left ventricular thrombus

Left ventricular aneurysm

Stroke prevention in other heart diseases

Absolute indications for oral anticoagulation (primary and secondary stroke prevention) include the following:

Mechanical heart valve

Mitral valve stenosis with any prior embolic event

Left atrial myxoma (qualified support from the data)

Intraventricular thrombus

Ventricular aneurysm with thrombus

Mobile thrombus in the ascending

Dilated cardiomyopathy (qualified support from the data)

Oral anticoagulation may be considered for patients with a large patent foramen ovale (PFO) under 3 circumstances:

Recurrent cerebral ischemia while the patient was receiving aspirin, 300 mg/day

Co-occurrence of PFO with atrial septal aneurysm

Co-occurrence of PFO with deep venous thrombosis of the leg or abdomen

Other cardiac indications for oral anticoagulation for secondary stroke prevention include the following:

Mitral valve prolapse with myxomatous leaflets

Rupture of chordae tendineae

Dyskinetic ventricular wall segment

Mitral ring calcifications

No current evidence-based guidelines address anticoagulation in patients with symptomatic stenoses of extracranial arteries.  The WASID trial showed no benefit to warfarin compared to aspirin in symptomatic intracranial disease.

Guidelines for secondary prevention

Class I recommendations from the American Heart Association/American Stroke Association (AHA/ASA) for prevention of stroke in patients who have experienced noncardioembolic ischemic stroke or TIA are as follows
:

Antiplatelet agents rather than oral anticoagulation are recommended to reduce the risk of recurrent stroke and other cardiovascular events (IA); aspirin monotherapy, the combination of aspirin and extended-release dipyridamole, and clopidogrel monotherapy are all acceptable options for initial therapy (IA)

For patients who have an ischemic cerebrovascular event while taking aspirin, increasing the dose of aspirin provides no additional benefit; the combination of aspirin and extended-release dipyridamole is recommended over aspirin alone (IB)

Class II recommendations are as follows:

Clopidogrel may be considered over aspirin alone (IIbB)

Clopidogrel is reasonable for patients allergic to aspirin (IIaB)

Class III recommendations are as follows:

Because of an increased risk of hemorrhage, combination therapy with aspirin and clopidogrel is not routinely recommended unless there is a specific indication for this therapy (IIIA)

In May 2013, new consensus guidelines on the delivery of optimized inpatient anticoagulation therapy were published.
These guidelines, which were endorsed by the Anticoagulation Forum, call for the increased use of technology (eg, computerized physician order entry, bar code scanning, and dose range checking) for decreasing medication errors and increasing multidisciplinary involvement in the anticoagulation management system.

Thrombophilia

In patients with cerebral ischemia of unknown origin who are younger than 40 years, a search for hereditary thrombophilia is generally recommended. Oral anticoagulation after cerebral ischemia is usually recommended for patients with the following disorders:

Antithrombin III deficiency

Protein C deficiency

Protein S deficiency

Activated protein C resistance

Plasminogen deficiency/inhibition

Dysfibrinogenemia

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