Is antiplatelet therapy (antiplatelet agents such as aspirin or clopidogrel) recommended for a patient with May-Thurner syndrome and a history of Deep Vein Thrombosis (DVT) who has undergone venous stenting?

Antiplatelet Therapy in May-Thurner Syndrome with DVT Post-Stenting

Antiplatelet therapy is NOT recommended as monotherapy but may be considered as adjunctive therapy to therapeutic anticoagulation in highly selected patients at exceptional risk for stent rethrombosis after venous stenting for May-Thurner syndrome. The primary treatment remains therapeutic anticoagulation, not antiplatelet agents.

Primary Treatment: Therapeutic Anticoagulation

After venous stent placement for May-Thurner syndrome with DVT, therapeutic anticoagulation using the same dosing, monitoring, and duration as for iliofemoral DVT patients without stents is the standard of care 1. This means:

• Direct oral anticoagulants (DOACs) are preferred over warfarin as first-line therapy, with apixaban, dabigatran, edoxaban, or rivaroxaban all being acceptable options 1, 2
• Minimum duration of 3 months is required for provoked DVT, with consideration for extended therapy (no scheduled stop date) for unprovoked cases with low-to-moderate bleeding risk 1, 2
• Target INR of 2.0-3.0 (target 2.5) if warfarin is used instead of a DOAC 1, 2

Role of Antiplatelet Therapy: Limited and Conditional

Antiplatelet therapy with concomitant anticoagulation may be considered (Class IIb recommendation) only in patients perceived to be at particularly high risk of rethrombosis after an individualized assessment of bleeding risk 1. High-risk features include:

• Poor inflow vein quality 1
• Imperfect anatomic result after stent placement 1
• Stent extension below the inguinal ligament into the common femoral vein 1

This represents a weak recommendation based on low-certainty evidence and should not be routine practice 1.

Evidence Against Aspirin as Primary Therapy

Aspirin is substantially inferior to anticoagulation for preventing recurrent VTE and should never replace therapeutic anticoagulation during the treatment phase 1, 2. When comparing anticoagulation to aspirin for secondary prevention:

• Anticoagulation is more effective than aspirin in preventing recurrent VTE without increased bleeding in direct comparison studies 1
• Aspirin provides only 30-35% risk reduction compared to placebo, far less than anticoagulation 2
• Aspirin is only considered after completing anticoagulation therapy in patients who decline extended anticoagulation, not as a substitute during active treatment 1

Special Consideration: Dual Antiplatelet Therapy Plus Anticoagulation

One case report described successful use of dual antiplatelet therapy (aspirin plus clopidogrel) combined with enoxaparin in a patient with recurrent thrombotic events despite multiple anticoagulation regimens and stent complications 3. However, this represents an extreme outlier case with arterial thrombosis and stent migration—not standard May-Thurner syndrome management.

Clinical Pitfalls to Avoid

Do not discontinue or reduce anticoagulation intensity when adding antiplatelet therapy 1. The combination increases bleeding risk substantially:

• Adding aspirin to anticoagulation increases major bleeding by approximately 7 more events per 1000 patients (though confidence intervals cross the null) 1
• For patients on aspirin for cardiovascular disease at DVT diagnosis, consider suspending aspirin while on therapeutic anticoagulation unless there is a recent acute coronary event or intervention 1

Anticoagulation alone is insufficient in May-Thurner syndrome without addressing the mechanical compression 4, 5. Stent placement is necessary to treat the underlying anatomical problem, followed by appropriate anticoagulation 4, 6, 5.

Monitoring and Duration

Reassess the risk-benefit ratio of continued anticoagulation at periodic intervals (e.g., annually) for patients on extended therapy 1, 2. The 12-month stent patency rates range from 60-100% with appropriate anticoagulation, though optimal duration remains uncertain due to limited evidence 6.

Stent occlusion or recurrent DVT rates at 12 months range from 0-40% in retrospective series, highlighting the importance of adequate anticoagulation 6. One case series reported successful outcomes with rivaroxaban after stenting, though partial thrombosis occurred in one patient requiring repeat intervention 7.