Can a patient with a recent subarachnoid hemorrhage (SAH) and a stented internal carotid artery aneurysm be given double antiplatelet therapy?

Dual Antiplatelet Therapy After Recent SAH with Stented Aneurysm

In a patient with a recently stented internal carotid artery aneurysm following subarachnoid hemorrhage, dual antiplatelet therapy (DAPT) is necessary and should be administered despite the recent hemorrhage, as the risk of stent thrombosis outweighs the risk of rebleeding once the aneurysm is secured. 1

Rationale for DAPT in This Clinical Scenario

The decision to use DAPT hinges on whether the aneurysm has been secured with a stent-requiring device:

• If an intracranial stent was placed, DAPT with aspirin 75-325 mg daily plus clopidogrel 75 mg daily is mandatory, starting with loading doses (aspirin 160-325 mg plus clopidogrel 300-600 mg) prior to or immediately after stent placement 1

• Duration of DAPT: Minimum 4 weeks for bare-metal stents, or 6-12 months for drug-eluting stents, followed by aspirin monotherapy indefinitely 1

• The risk of catastrophic stent thrombosis if DAPT is withheld far exceeds the risk of rebleeding from a secured aneurysm 2

Evidence Supporting DAPT Safety Post-SAH

Research demonstrates that antiplatelet therapy can be safely administered in the acute SAH setting when endovascular treatment is performed:

• A retrospective study of 35 ruptured aneurysms treated with coiling showed that preprocedural administration of aspirin 200 mg and clopidogrel 150 mg at least 2 hours before the procedure resulted in only one case (2.9%) of intraoperative thrombosis with no clinical symptoms, and no bleeding complications despite CSF drainage in three cases 3

• In patients requiring VP shunt placement while on DAPT after stent-assisted coiling, the rate of symptomatic intracranial hemorrhage was low (8.3%), and the single symptomatic case resulted in no permanent morbidity 2

Critical Distinction: Stent vs. Coil-Only Treatment

This recommendation applies specifically to stented aneurysms. The evidence base differs significantly:

• European guidelines note that "acute stroke patients with AF and 'symptomatic' high-grade carotid stenosis should preferably undergo carotid endarterectomy, as carotid stenting would result in the need for dual antiplatelet therapy" - acknowledging that stenting mandates DAPT even in hemorrhagic contexts 4

• For coil-only embolization without stent assistance, the evidence does not support routine DAPT. The ISAT substudy found no benefit of antiplatelets during or after coiling in SAH patients (ratio of relative risks 1.24, P=0.56 for 2-month outcomes) 5

Guideline Perspective on SAH and Anticoagulation

While guidelines address oral anticoagulation more than DAPT specifically:

• European guidelines state: "There is little evidence to guide the resumption of OAC treatment in patients with AF following subarachnoid hemorrhage. A thorough assessment is necessary." 4

• When SAH occurs in AF patients on anticoagulation "in the absence of a remediable aetiology it seems prudent not to re-initiate OAC treatment" 4

• However, these recommendations apply to anticoagulation for atrial fibrillation, not to DAPT for stent thrombosis prevention - a critical distinction, as stent thrombosis carries immediate catastrophic risk 4

Practical Management Algorithm

Step 1: Confirm aneurysm is secured

• Verify complete aneurysm obliteration or adequate stent deployment on post-procedure angiography 3

Step 2: Initiate or continue DAPT immediately

• If not already loaded, give aspirin 160-325 mg plus clopidogrel 300-600 mg 1
• Transition to maintenance dosing: aspirin 75-325 mg daily plus clopidogrel 75 mg daily 1

Step 3: Monitor for bleeding complications

• Serial neurological examinations during the first 24-48 hours 3
• CT imaging if any neurological deterioration occurs 2

Step 4: Duration planning

• Continue DAPT for minimum 4 weeks (bare-metal stent) or 6-12 months (drug-eluting stent) 1
• Transition to aspirin monotherapy indefinitely after completing DAPT course 1

Common Pitfalls to Avoid

• Never discontinue DAPT prematurely before the minimum duration (4 weeks for bare-metal, 6 months for drug-eluting stents), as this dramatically increases stent thrombosis risk 1

• Do not withhold DAPT due to fear of rebleeding once the aneurysm is secured - the secured aneurysm is no longer a bleeding source, while the stent remains a thrombosis risk 3, 2

• Avoid using DAPT for coil-only embolization without stent assistance, as evidence does not support benefit and may increase bleeding risk unnecessarily 5

• Do not confuse recommendations about oral anticoagulation (which should generally be avoided post-SAH without compelling indication) with DAPT for stent thrombosis prevention - these are distinct clinical scenarios with different risk-benefit profiles 4