What is the recommended management for an internal iliac artery mural thrombus?

Management of Internal Iliac Artery Mural Thrombus

Immediate anticoagulation with therapeutic heparin is the cornerstone of initial management for internal iliac artery mural thrombus, followed by urgent cross-sectional imaging (CTA or MRA) to define thrombus extent and guide definitive endovascular or surgical intervention based on symptom severity and tissue threat. 1

Initial Medical Management

Anticoagulation (First-Line Therapy)

• Start therapeutic anticoagulation immediately upon diagnosis to prevent thrombus propagation and distal embolization. 1 This is typically a heparin infusion and should be initiated before definitive imaging if clinical suspicion is high.

• The primary goal is to stabilize the thrombus and limit extension while planning definitive therapy. 1

Antiplatelet Therapy

• Initiate aspirin 75-325 mg daily as adjunctive therapy to reduce major adverse cardiovascular events (MACE) and cardiovascular mortality. 1, 2 This should be started in all patients with symptomatic peripheral arterial disease, including those with iliac artery thrombus.

Diagnostic Imaging Strategy

• Obtain CTA or MRA urgently to reveal the exact nature, level, and extent of thrombus, assess underlying atherosclerotic plaque, and plan the most appropriate treatment strategy. 1

• Cross-sectional imaging is essential to differentiate mural thrombus from other pathology (such as aneurysm with wall thrombus) and to assess for tissue threat. 1

• Catheter-directed angiography can be considered as both diagnostic and therapeutic if tissue is threatened and immediate flow restoration is needed. 1

Risk Stratification and Treatment Selection

Asymptomatic or Minimally Symptomatic (No Tissue Threat)

• Continue therapeutic anticoagulation for at least 3 months; consider indefinite therapy for unprovoked events. 2, 3

• Add comprehensive cardiovascular risk reduction: high-dose statin therapy, blood pressure control targeting <130/80 mmHg, diabetes management with HbA1c <7%, and smoking cessation. 2

• Initiate supervised exercise therapy (SET) to improve walking distance in patients with claudication. 1

Symptomatic with Acute Limb Ischemia (ALI)

• Proceed urgently to catheter-directed intervention for prompt restoration of flow to preserve limb function. 1

• Catheter-directed thrombolysis (CDT) is the preferred first-line endovascular approach for viable limbs when a guide wire can be passed across the lesion. 1 If wire passage fails, regional thrombolysis can be considered. 1

• Catheter-directed mechanical thrombectomy can be used as adjunctive therapy to thrombolysis, reducing required thrombolytic drug dose by 40-50% and shortening infusion time. 3

• Covered stent-graft placement is a viable treatment option to exclude thrombus-containing lesions and prevent distal embolization, particularly when thrombotic material is localized in a large vessel. 4 This approach entraps the thrombotic mass and provides immediate flow restoration with optimal results. 4

Aneurysm with Mural Thrombus

• If imaging reveals an internal iliac artery aneurysm with wall thrombus, endovascular repair with stent-graft placement is the preferred first-line approach when anatomically suitable, offering lower mortality compared to open surgery. 2

• Symptomatic iliac aneurysms require repair regardless of diameter; common iliac aneurysms ≥3.0-3.5 cm warrant intervention based on rupture risk. 2

Endovascular vs. Surgical Decision-Making

• Endovascular techniques (CDT, mechanical thrombectomy, stent-graft placement) achieve 1-year limb salvage rates similar to surgery with lower mortality rates, though with higher rates of recurrent ischemia. 1

• Open surgical thrombectomy is reserved for patients with contraindications to thrombolysis, failed endovascular therapy, or imminent gangrene. 3

• The endovascular approach allows treatment of underlying lesions after thrombus removal. 1

Long-Term Anticoagulation Strategy

• Continue therapeutic anticoagulation with the same dosing and monitoring as for standard iliac arterial thrombosis: minimum 3 months, indefinite for unprovoked events. 2, 3

• Direct oral anticoagulants (DOACs) are preferred over warfarin in non-cancer patients because they lower bleeding risk. 2

• Single-dose DOAC therapy (e.g., edoxaban 30 mg daily) has demonstrated efficacy for complete thrombus resolution in iliac vessel thrombosis, even without acute-phase parenteral anticoagulation in select cases. 5

Critical Pitfalls to Avoid

• Never delay intervention for symptomatic presentations to obtain additional imaging, as symptomatic thrombus indicates imminent embolization or limb threat. 2

• Exercise extreme caution with thrombolytic therapy in patients with recent surgery (particularly spinal surgery within the past month), as bleeding risk is prohibitive. 1 In such cases, mechanical thrombectomy or surgical approaches are preferred.

• Do not rely on anticoagulation alone when significant thrombus burden is present with symptoms, as mechanical removal yields superior outcomes for limb salvage. 1, 3

• Screen for concurrent aortoiliac atherosclerotic disease and contralateral iliac pathology, as isolated iliac thrombus frequently coexists with other vascular disease requiring surveillance or intervention. 2

• Assess for underlying hypercoagulable states or cardiac sources of embolism (atrial fibrillation, recent myocardial infarction) that may have precipitated the thrombus. 1