For a patient with an occlusive lower extremity thrombus, do I need to refer to interventional cardiology?

Immediate Referral to Vascular Specialist Required

Yes, you must urgently refer a patient with an occlusive lower extremity thrombus to a specialist capable of performing revascularization—this is typically vascular surgery, interventional radiology, or interventional cardiology, depending on your institution's resources and expertise. The key is immediate access to both endovascular and surgical revascularization capabilities, as acute limb ischemia is a medical emergency requiring evaluation within hours. 1, 2

Critical Time-Sensitive Actions

Immediate Management (Before Transfer)

• Start systemic anticoagulation with unfractionated heparin immediately unless contraindicated (bolus 75-100 units/kg IV, then continuous infusion 20,000-40,000 units/24 hours) 1, 2
• This prevents thrombus propagation both proximally and distally, which occurs rapidly in low-flow states 3
• Do not delay anticoagulation while waiting for imaging or specialist consultation 4

Assess Limb Viability Using the "5 P's"

Rapidly determine the Rutherford category to guide urgency: 1, 2

• Category I (Viable): No immediate threat—anticoagulate and arrange scheduled evaluation
• Category IIa (Marginally threatened): Salvageable with prompt treatment—urgent referral within hours
• Category IIb (Immediately threatened): Requires emergency revascularization—transfer immediately
• Category III (Irreversible): Insensate, immobile limb with muscle rigor—primary amputation likely needed

The presence of motor deficit (paralysis) or sensory loss (anesthesia) indicates Category IIb or III and demands immediate action, as skeletal muscle tolerates ischemia for only 4-6 hours. 1

Which Specialist to Consult

The Answer Depends on Local Resources

Contact the specialist at your institution who can most rapidly perform revascularization—whether endovascular or surgical. 1 The specific specialty matters less than their ability to:

1. Assess limb viability immediately
2. Perform or arrange urgent revascularization (catheter-based thrombolysis, mechanical thrombectomy, or surgical thromboembolectomy)
3. Manage post-revascularization complications (compartment syndrome, reperfusion injury)

Interventional Cardiology as an Option

While vascular surgery has traditionally managed peripheral arterial disease, interventional cardiologists are increasingly performing lower extremity revascularization and may be appropriate consultants if they have specific training and experience in peripheral interventions. 5 Many institutions now have interventional cardiologists with dedicated peripheral arterial disease expertise who perform catheter-based thrombolysis and mechanical thrombectomy. 1

The critical factor is not the specialty name but rather the clinician's ability to perform timely revascularization. If your interventional cardiology team routinely performs peripheral interventions, they are appropriate consultants. If not, vascular surgery or interventional radiology should be contacted. 1

Revascularization Strategy

Endovascular Approach (First-Line for Most Cases)

Catheter-based thrombolysis is effective and indicated for acute limb ischemia with a salvageable limb (Categories I, IIa, IIb) when symptom duration is <14 days. 1 This approach:

• Achieves similar 1-year limb salvage rates as surgery (82%) 1
• Reduces perioperative mortality compared to surgery (16% vs 49% major cardiopulmonary complications) 1
• Allows treatment of underlying lesions after clot dissolution 1
• Provides gradual reperfusion, potentially avoiding reperfusion injury 1

Mechanical thrombectomy devices are useful as adjunctive therapy and may allow more rapid flow restoration, particularly when thrombolysis is contraindicated or time is critical. 1

Surgical Approach (When Indicated)

Surgical thromboembolectomy or bypass is appropriate for: 1

• Embolic occlusions (especially isolated suprainguinal emboli)
• Failed endovascular therapy
• Category IIb limbs when endovascular delay would jeopardize viability
• Category III limbs requiring primary amputation

Common Pitfalls to Avoid

1. Delaying anticoagulation while arranging imaging or consultation—start heparin immediately 4
2. Performing extensive imaging that delays revascularization in Category IIb patients—clinical assessment alone is sufficient to proceed 1
3. Assuming you need a specific specialty rather than focusing on who can revascularize fastest at your institution 1
4. Attempting revascularization in Category III limbs with irreversible damage—primary amputation is indicated 1, 2
5. Failing to monitor for compartment syndrome after revascularization—prophylactic fasciotomy may be needed 2

Post-Revascularization Considerations

After successful revascularization, patients require: 2

• ICU monitoring for compartment syndrome and reperfusion injury
• Continued anticoagulation
• Evaluation for underlying cause (echocardiography for embolic source, thrombophilia screening if indicated) 4
• Regular vascular follow-up (at least twice yearly due to high recurrence rates) 2

The bottom line: Call whoever at your hospital can perform urgent revascularization—whether that's vascular surgery, interventional radiology, or interventional cardiology—and start heparin immediately while arranging transfer.