Is it safe to place a 26-year-old woman with a 4‑mm right ophthalmic internal carotid artery aneurysm and hereditary hemorrhagic telangiectasia on dual antiplatelet therapy for an endovascular flow‑diverting stent?

Dual Antiplatelet Therapy for Flow-Diverting Stent in HHT Patient with Ophthalmic Artery Aneurysm

This patient should NOT receive dual antiplatelet therapy for a flow-diverting stent given her diagnosis of hereditary hemorrhagic telangiectasia (HHT), as the substantially elevated bleeding risk from HHT directly contradicts the mandatory prolonged dual antiplatelet therapy required for flow-diverting stents.

Critical Safety Concerns with DAPT in HHT

Bleeding Risk Profile in HHT

• HHT patients have an inherently high bleeding risk due to systemic vascular dysplasia affecting multiple organ systems, with epistaxis being the most common manifestation but bleeding can occur from any mucosal surface 1
• The disease causes telangiectasias and arteriovenous malformations throughout the body, creating multiple potential bleeding sites that would be exacerbated by antiplatelet therapy 2, 1
• Even selective arterial embolization for epistaxis in HHT patients—a procedure that doesn't require antiplatelet therapy—shows recurrent bleeding in 43% of patients within 6-24 months, demonstrating the persistent bleeding tendency 2

DAPT Requirements for Flow-Diverting Stents

• Flow-diverting stents require mandatory dual antiplatelet therapy for a minimum of 6-12 months, similar to drug-eluting coronary stents, to prevent catastrophic stent thrombosis 3
• The typical regimen consists of aspirin (75-325 mg daily) plus clopidogrel (75 mg daily) for at least 4 weeks minimum, but drug-eluting devices may require up to 24 months of therapy 3
• Premature discontinuation of DAPT dramatically increases the risk of stent thrombosis, myocardial infarction, and death, with stent thrombosis carrying a 20-45% mortality rate 3

The Fundamental Contradiction

• The MATCH trial demonstrated that dual antiplatelet therapy (clopidogrel plus aspirin) significantly increased major hemorrhage risk with a 1.3% absolute increase in life-threatening bleeding compared to single antiplatelet therapy 3
• In a patient with HHT—who already has multiple bleeding sites and recurrent hemorrhagic episodes—adding mandatory DAPT creates an unacceptable bleeding hazard 1
• Recent evidence shows that even HHT patients requiring anticoagulation for thrombosis experience worsened epistaxis as the most frequent complication, and this is with therapeutic anticoagulation alone, not combined with antiplatelet agents 1

Alternative Management Strategies

Conservative Management

• For a small (4 mm), incidentally discovered, unruptured ophthalmic artery aneurysm in a young patient, observation with serial imaging is a reasonable first approach 4, 5
• Ophthalmic artery aneurysms often remain asymptomatic until they become large enough to cause visual symptoms through mass effect 4, 5
• The natural history of small unruptured aneurysms must be weighed against treatment risks, particularly in this high-bleeding-risk patient

Surgical Clipping if Treatment Required

• If the aneurysm requires treatment due to growth or symptoms, microsurgical clipping is strongly preferred over endovascular therapy in this patient 4, 5
• Surgical clipping does not require prolonged dual antiplatelet therapy, eliminating the primary safety concern 5
• A case report of a 62-year-old woman with an 8 mm ruptured ophthalmic artery aneurysm successfully treated with microsurgical clipping achieved excellent outcomes (GOS 5, GOS-E 8) without requiring DAPT 5
• Even in cases where endovascular treatment was initially attempted but failed, surgical clipping provided definitive treatment 4

Endovascular Alternatives Without Flow Diversion

• If endovascular treatment is absolutely necessary, consider coiling without stent assistance to avoid the DAPT requirement, though this may not be technically feasible for all aneurysm morphologies 4
• Standard coiling typically requires only aspirin monotherapy or short-term DAPT (1 month), substantially reducing bleeding risk compared to flow-diverting stents 3

Clinical Decision Algorithm

Step 1: Assess Treatment Necessity

• Is the aneurysm causing symptoms (visual changes, headaches, cranial nerve deficits)? 4, 5
• Has the aneurysm demonstrated growth on serial imaging?
• If NO to both: Recommend observation with serial MRA/CTA every 6-12 months

Step 2: If Treatment Required, Assess Surgical Candidacy

• Is the patient a surgical candidate for microsurgical clipping? 5
• Are there anatomical features that would make surgical access difficult?
• If surgical candidate: Proceed with microsurgical clipping (avoids DAPT requirement)

Step 3: If Endovascular Treatment Necessary

• Can the aneurysm be treated with coiling alone without stent assistance? 4
• If YES: Proceed with coiling alone (requires only aspirin or short-term DAPT)
• If NO: Reconsider surgical option or observation, as flow-diverting stent with mandatory prolonged DAPT is contraindicated in HHT

Critical Pitfalls to Avoid

• Do not proceed with flow-diverting stent placement assuming you can use shorter DAPT duration—this dramatically increases stent thrombosis risk with potentially fatal consequences 3
• Do not underestimate the bleeding risk in HHT patients—these patients have systemic vascular dysplasia with multiple potential bleeding sites that will be exacerbated by antiplatelet therapy 2, 1
• Do not assume endovascular treatment is always safer than surgery—in this specific scenario, the mandatory DAPT requirement makes endovascular flow diversion more dangerous than microsurgical clipping 4, 5
• Do not treat an incidentally discovered small aneurysm without careful consideration of natural history versus treatment risks—observation may be the safest option 4