How should I evaluate and manage a 50‑year‑old woman with recurrent extensive proximal left‑leg deep‑vein thrombosis and uterine‑fibroid‑related bleeding suggestive of May‑Thurner syndrome?

Evaluation and Management of Recurrent Proximal Left-Leg DVT with May-Thurner Syndrome

In a 50-year-old woman with recurrent extensive proximal left-leg DVT and uterine-fibroid bleeding, you must pursue combined catheter-directed thrombolysis (or pharmacomechanical thrombectomy) plus iliac vein stenting in addition to therapeutic anticoagulation, because anticoagulation alone leads to significantly higher recurrent VTE rates when May-Thurner syndrome is present. 1

Immediate Diagnostic Workup

Confirm Recurrent DVT

• Begin with proximal compression ultrasound (CUS) as the initial test for suspected recurrent ipsilateral DVT 2
• If prior ultrasound is unavailable for comparison and current CUS is abnormal, obtain venography (Grade 1B) or highly sensitive D-dimer (Grade 2B) to confirm recurrence 2
• If CUS shows a new noncompressible segment in the common femoral or popliteal vein, treat for DVT immediately without confirmatory venography (Grade 1B) 2
• If CUS shows a ≥4-mm increase in residual venous diameter compared to prior imaging, treat for DVT (Grade 2B) 2

Identify May-Thurner Syndrome

• Recurrent left-sided proximal DVT in a 50-year-old woman with uterine fibroids (estrogen exposure) is highly suspicious for May-Thurner syndrome 2, 3
• During pregnancy and in women on hormonal therapy, 80% of DVTs occur in the left leg, and 64% are iliofemoral with 17% isolated iliac vein thromboses 2
• Order CT venography or MR venography to visualize compression of the left common iliac vein by the right common iliac artery against the lumbar spine 4, 5
• Young patients presenting with left-sided DVT should raise immediate suspicion for this anatomic variant, which is present in >20% of the population 1, 5

Critical Management Decision: Anticoagulation Alone Is Insufficient

Do not rely on anticoagulation alone when May-Thurner syndrome is identified; the persistent anatomic compression predisposes to recurrent VTE despite adequate anticoagulation. 1, 3, 5

Why Anticoagulation Alone Fails

• The anatomic compression of the left iliac vein persists despite therapeutic anticoagulation, making mechanical relief of the obstruction essential 1
• Observational data consistently show recurrent VTE is more frequent with anticoagulation alone compared to thrombectomy followed by iliac vein stenting 1
• Case series demonstrate patients continue to develop DVT recurrence and even arterial thromboses while on full anticoagulation (rivaroxaban, enoxaparin, warfarin) without stenting 6

Definitive Treatment Algorithm

Step 1: Initiate Immediate Anticoagulation

• Start therapeutic anticoagulation immediately upon DVT diagnosis before any intervention 7, 1
• Direct oral anticoagulants (DOACs) are preferred over warfarin for the treatment phase 7
• If heparins are used, low-molecular-weight heparin (LMWH) is preferred over unfractionated heparin 7

Step 2: Urgent Endovascular Intervention (Within 14 Days)

• Perform catheter-directed thrombolysis (CDT) or pharmacomechanical thrombectomy (PMT) to remove thrombus burden before stenting (Class IIa) 1
• Do not delay endovascular intervention; early thrombus removal within 14 days yields optimal outcomes 1
• Pharmacomechanical thrombectomy reduces required thrombolytic drug dose by 40-50% and shortens infusion time compared to CDT alone 1

Step 3: Iliac Vein Stenting

• After thrombus removal, perform balloon angioplasty followed by self-expanding iliac vein stent placement because angioplasty alone typically fails 1, 3
• Confine stents to the iliac vein whenever feasible to optimize long-term patency 1
• If the lesion extends into the common femoral vein, caudal stent extension is reasonable but expect modestly lower patency (90% vs 84%) 1
• All seven patients in one series treated with mechanical thrombectomy and stenting achieved 100% intraoperative clot resolution and 100% primary stent patency at mean 13-month follow-up 3

Post-Intervention Anticoagulation Strategy

Duration Based on Risk Stratification

• Continue therapeutic anticoagulation with the same dosing and monitoring as for iliofemoral DVT without stents 1
• Minimum duration is 3 months for all patients 7, 1
• For unprovoked DVT (no clear provoking factor beyond May-Thurner anatomy): consider indefinite anticoagulation with annual reevaluation 7, 1
• For provoked DVT (e.g., recent surgery, trauma): stop after 3 months 7
• In young patients with patent stents, no prior VTE, and confirmed May-Thurner anatomy: stopping after 3-12 months is considered safe 1

Adjunctive Antiplatelet Therapy

• Add antiplatelet therapy to anticoagulation in high-risk patients (poor inflow vein quality, suboptimal stent result) after individualized bleeding-risk assessment 1
• One case required dual antiplatelet therapy (aspirin + clopidogrel) plus enoxaparin to prevent recurrent arterial and venous thromboses after multiple failures 6

Special Consideration: Uterine Fibroid Bleeding

Balancing Thrombosis and Bleeding Risk

• This patient's uterine fibroid bleeding creates a competing risk with anticoagulation requirements
• Therapeutic anticoagulation is mandatory for proximal DVT because the risk of fatal PE far outweighs bleeding risks 8
• Coordinate with gynecology for definitive fibroid management (hormonal therapy, uterine artery embolization, or surgical options) to minimize bleeding while maintaining anticoagulation
• If absolute contraindication to anticoagulation develops, place an inferior vena cava filter (preferably retrievable) and initiate anticoagulation as soon as the contraindication resolves 7

Compression Therapy

• Prescribe 30-40 mm Hg knee-high elastic compression stockings for at least 2 years to reduce post-thrombotic syndrome risk by approximately 50% 1
• Although recent trials (SOX trial) did not show specific benefit in preventing post-thrombotic syndrome, compression remains reasonable for symptomatic management 7, 1

Expected Outcomes

• At 3 years after iliac vein stenting, 79% maintain pain reduction and 66% maintain swelling reduction 1
• Stent fracture occurs in approximately 1% of cases and can be managed by implanting a second stent 1
• Primary stent patency is 100% in young patients treated with thrombectomy and stenting at mean 13-month follow-up 3

Critical Pitfalls to Avoid

• Never treat May-Thurner syndrome with anticoagulation alone; multiple case reports document recurrent DVT and PE despite full anticoagulation without stenting 9, 6, 4, 5
• Do not stop anticoagulation prematurely; even with successful stenting, minimum 3-month duration is required 7, 1
• Do not delay intervention beyond 14 days from symptom onset; early thrombus removal yields optimal outcomes 1
• Screen all young women on oral contraceptives presenting with left-sided iliofemoral DVT for May-Thurner syndrome 3