What is the best initial approach for an elderly patient with a long history of intermittent claudication (IC), presenting with leg pain, an ankle-brachial index (ABI) of less than 0.3, and a computed tomography angiogram (CTA) showing an artery occlusion of more than 3 cm?

Urgent Revascularization via Catheter-Based Thrombolysis or Thrombectomy

This patient requires immediate catheter-based thrombolysis or mechanical thrombectomy as the initial intervention, not amputation, not anticoagulation alone, and not embolectomy (which is typically reserved for acute embolic events rather than chronic atherosclerotic occlusions). The presentation of an ABI <0.3 with a >3 cm arterial occlusion represents critical limb-threatening ischemia (CLTI) superimposed on chronic claudication, demanding urgent revascularization to salvage the limb 1, 2.

Clinical Context and Urgency

• ABI <0.3 indicates severe ischemia requiring intervention within hours to prevent permanent tissue damage and limb loss 2, 3
• The 2-month history of claudication suggests chronic peripheral arterial disease with acute-on-chronic deterioration 2, 3
• The principle of "time is tissue" applies: delays beyond 4-6 hours significantly increase risk of irreversible muscle damage and amputation 2

Why Thrombolysis/Thrombectomy is the Correct Answer

Catheter-based thrombolysis is a Class I recommendation (Level of Evidence: A) for acute limb ischemia of less than 14 days' duration 1. While this patient has chronic claudication, the acute worsening with severe ischemia (ABI <0.3) represents an acute-on-chronic presentation requiring urgent intervention 2.

• Mechanical thrombectomy devices are Class IIa recommendations as adjunctive therapy for acute limb ischemia due to peripheral arterial occlusion 1
• Modern endovascular approaches combining catheter-directed thrombolysis with mechanical thrombectomy have similar 1-year survival and limb salvage rates compared to open surgery 2
• For occlusions >3 cm, an endovascular-first strategy is appropriate in most patients, particularly those with significant comorbidities common in elderly patients 1, 4

Why the Other Options Are Wrong

Amputation (Option A) is Premature and Inappropriate

• Amputation should only be considered as primary therapy in patients with significant necrosis of weight-bearing portions of the foot, uncorrectable flexion contracture, paresis of the extremity, refractory ischemic rest pain, sepsis, or very limited life expectancy 1
• The question does not describe any of these features—only leg pain and arterial occlusion 2
• Revascularization must be attempted first before considering amputation 2, 3

Enoxaparin (Option D) is Grossly Inadequate

• Anticoagulation alone does not address the arterial occlusion causing critical ischemia 2
• While systemic anticoagulation with unfractionated heparin should be started immediately to prevent thrombus propagation, this is an adjunct to—not a replacement for—revascularization 2
• Enoxaparin (low molecular weight heparin) is not the preferred agent; unfractionated heparin is recommended for immediate anticoagulation in acute limb ischemia 2

Embolectomy (Option C) is Not Indicated

• Embolectomy is primarily for acute embolic occlusions (typically from atrial fibrillation or cardiac sources), not chronic atherosclerotic disease with acute thrombosis 2
• The 2-month history of claudication indicates underlying chronic atherosclerotic disease, not an acute embolic event 3
• CTA showing >3 cm occlusion suggests thrombotic occlusion of diseased vessels rather than embolism 5

Immediate Management Algorithm

1. Start systemic anticoagulation immediately with intravenous unfractionated heparin to prevent thrombus propagation 2
2. Obtain urgent vascular surgery consultation even before completing all imaging 2
3. Proceed to catheter-based intervention with thrombolysis and/or mechanical thrombectomy based on the CTA findings 1, 2
4. Assess for the "6 Ps" of limb threat: pain, paralysis, paresthesias, pulselessness, pallor, and poikilothermia (cold extremity) to determine urgency 2

Post-Intervention Management

• Initiate dual antiplatelet therapy or rivaroxaban 2.5 mg twice daily plus aspirin 100 mg daily after successful revascularization to reduce major adverse limb events 2
• Optimize cardiovascular risk factors: high-dose statin for LDL-C target <55 mg/dL, blood pressure control to <130/80 mmHg, and HbA1c <7% 2
• Follow-up within 2 weeks to assess renal function, access site complications, and limb perfusion 2

Critical Pitfalls to Avoid

• Do not delay revascularization for medical optimization in patients with threatened limbs 2
• Do not rely on ABI alone for diagnosis—the CTA has already defined the anatomy and severity 2, 5
• Do not proceed directly to amputation without attempting revascularization unless the limb is clearly unsalvageable 1, 3
• Do not use anticoagulation as definitive therapy—it is only a temporizing measure while planning revascularization 2