In a patient with less than 50 % carotid artery stenosis and a recent subdural hematoma (SDH), is antiplatelet therapy indicated and when can it be safely started?

Antiplatelet Therapy in <50% Carotid Stenosis with Recent Subdural Hematoma

In a patient with less than 50% carotid stenosis and recent subdural hematoma, antiplatelet therapy is indicated for secondary stroke prevention, but must be delayed until the hemorrhagic risk stabilizes, typically at least 4 weeks after the SDH, and should be initiated as single antiplatelet therapy only—never dual antiplatelet therapy in this context.

Why Antiplatelet Therapy IS Indicated Despite <50% Stenosis

• Long-term antiplatelet therapy should be prescribed to all patients with ischemic stroke or TIA who are not on anticoagulation, regardless of the degree of carotid stenosis 1.
• Carotid endarterectomy is not recommended for <50% symptomatic stenosis, making medical management with antiplatelet therapy the primary treatment strategy 1.
• The presence of carotid atherosclerosis at any degree indicates systemic atherosclerotic disease requiring antiplatelet therapy for vascular event prevention 1, 2, 3.

Critical Contraindication: Active Intracranial Hemorrhage

• Clopidogrel and all antiplatelet agents are absolutely contraindicated in patients with active pathological bleeding, including intracranial hemorrhage such as subdural hematoma 4.
• The presence of recent SDH creates a hemorrhagic conversion risk that makes dual antiplatelet therapy completely inappropriate 5.
• Patients with large stroke burden, hemorrhagic transformation, or recent intracranial bleeding are ineligible for dual antiplatelet therapy 5.

Timing of Antiplatelet Initiation After SDH

Delay all antiplatelet therapy until the subdural hematoma stabilizes and repeat neuroimaging confirms no expansion of hemorrhage 5.

Recommended Timeline:

• Wait at least 4 weeks after SDH before initiating any antiplatelet therapy, as this allows sufficient time for hemorrhagic stabilization 1, 5.
• Obtain repeat CT or MRI to confirm SDH resolution or stability before starting antiplatelet agents 1, 5.
• Monitor closely for neurological deterioration in the first 24-72 hours after antiplatelet initiation 5.

Evidence Supporting Delayed Initiation:

• In AF patients with ICH (which includes subdural hematoma), anticoagulation should be delayed beyond the acute phase (approximately 48 hours) and probably for at least 4 weeks 1.
• This same principle applies to antiplatelet therapy in the setting of recent SDH, as the hemorrhagic risk must be minimized 1, 5.

Single Antiplatelet Therapy Protocol (NOT Dual)

Once the SDH has stabilized, initiate single antiplatelet therapy only:

First-Line Options:

• Aspirin 75-325 mg daily (most commonly 81 mg daily for long-term use) 1, 6
• Clopidogrel 75 mg daily as an alternative for aspirin-intolerant patients 1, 4

Why NOT Dual Antiplatelet Therapy:

• The combination of aspirin plus clopidogrel is not recommended for secondary prevention of cerebrovascular disease in patients without acute coronary disease or recent coronary stent 1.
• Dual antiplatelet therapy significantly increases bleeding risk, which is unacceptable in a patient with recent SDH 5, 4.
• There is insufficient evidence to recommend routine aspirin-clopidogrel combination therapy in patients with <50% carotid stenosis 6.

Comprehensive Medical Management Beyond Antiplatelets

Intensive medical therapy is recommended regardless of stenosis severity:

• High-dose statin therapy targeting LDL cholesterol of 1.8 mmol/L (70 mg/dL) 1, 7.
• Blood pressure control with target systolic BP <140 mmHg 1, 8.
• Diabetes management according to national guidelines 1.
• Smoking cessation, diet modification, and at least moderate physical activity 1, 8.

Critical Pitfalls to Avoid

• Never initiate antiplatelet therapy during the acute phase of SDH, as this dramatically increases rebleeding risk 5, 4.
• Never use dual antiplatelet therapy in patients with recent intracranial hemorrhage, even if they have symptomatic carotid disease 5.
• Do not assume that <50% stenosis means no treatment is needed—antiplatelet therapy is still indicated for secondary stroke prevention 1.
• Avoid premature discontinuation of antiplatelet therapy once started, as this increases cardiovascular event risk 4.

Monitoring After Antiplatelet Initiation

• Repeat neuroimaging if any new neurological symptoms develop after starting antiplatelet therapy 5.
• Monitor for signs of bleeding complications including gastrointestinal bleeding, epistaxis, hematuria, and bruising 4.
• Watch for rare but serious complications such as thrombotic thrombocytopenic purpura (TTP), which can occur within 2 weeks of clopidogrel initiation 4.

Long-Term Strategy

Single antiplatelet therapy should be continued indefinitely for secondary stroke prevention 1, 8. The patient should remain on aspirin 75-100 mg daily or clopidogrel 75 mg daily for life, combined with aggressive risk factor modification including statin therapy, blood pressure control, and lifestyle interventions 1, 7.