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Acute Occlusion of the Right Femoral Artery in a 40-Year-Old Man

Definition & Overview

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Etiology

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Clinical Features - The "Six Ps"

1. Pain - Sudden, severe pain in the limb (earliest symptom); at rest, worsened by movement
2. Pallor - The limb appears pale or mottled due to lack of perfusion; later becomes cyanotic/mottled
3. Pulselessness - Absent femoral, popliteal, dorsalis pedis, and posterior tibial pulses distal to the occlusion; a palpable femoral pulse that disappears at the bifurcation localizes the embolus
4. Paresthesia - Tingling and numbness; reflects ischemia of sensory nerve fibers (early ischemia sign)
5. Paralysis - Motor weakness or complete loss of movement; indicates advanced ischemia of motor nerves and muscle
6. Poikilothermia (Perishingly cold) - The limb is cold to touch, with a distinct temperature border indicating the level of occlusion

The presence of paresthesia and paralysis indicates threatened limb requiring immediate intervention.

Additional Findings

• Mottling (blue-red discoloration that blanches on pressure) - early; progresses to fixed staining (irreversible)
• Absent Doppler signals distally
• Signs of underlying cause: irregular pulse (AF), cardiac murmur, recent MI, or known peripheral vascular disease

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Rutherford Classification (Severity Grading)

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Investigations

Immediate (Bedside)

• Continuous-wave Doppler of peripheral signals - assess level and severity; compare multiphasic vs. monophasic vs. absent signals with the contralateral limb
• Ankle-Brachial Index (ABI) - typically <0.3 in acute occlusion (normal >0.9)
• 12-lead ECG - detect atrial fibrillation, recent MI
• Pulse oximetry on the affected digit

Laboratory Tests

• Full blood count (CBC) - baseline, detect polycythemia
• Coagulation profile (PT, aPTT, INR, fibrinogen) - before thrombolysis
• Urea, creatinine, electrolytes - baseline renal function; critical for contrast use and monitoring reperfusion injury
• Serum lactate, CK (creatine kinase) - assess severity of muscle ischemia/necrosis
• Serum potassium - hyperkalemia from ischemic muscle
• Blood glucose, lipid profile - risk factor assessment
• Cardiac enzymes (Troponin) - if MI suspected as cause
• Hypercoagulable screen (antiphospholipid antibodies, protein C, protein S, factor V Leiden, antithrombin III) - especially important in a young patient; must be done before starting heparin if time permits

Imaging

• Duplex ultrasound (Doppler) - First-line non-invasive imaging; identifies site of occlusion, differentiates embolism from thrombosis, assesses collaterals. Rapid and bedside-available.
• CT Angiography (CTA) - Most widely used; rapid, non-invasive; excellent for defining anatomy, level of occlusion, inflow/outflow, and planning intervention. Preferred if arteriography is not immediately available.
• Conventional Catheter Arteriography - Gold standard; allows simultaneous diagnosis and therapeutic intervention (thrombolysis, angioplasty). Shows the meniscus sign (sharp cutoff) in embolism or irregular occlusion with collaterals in thrombosis. Arteriography is not mandatory if the clinical picture is clear, but all patients should be positioned for fluoroscopic access.
• MR Angiography - Alternative if contrast is contraindicated; less practical in emergency setting
• Echocardiography - To identify cardiac source (intracardiac thrombus, valvular disease, LV aneurysm); transoesophageal echo (TOE) is more sensitive

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Management

Immediate (Emergency) Measures - "Do These Now"

1. IV access + resuscitation - IV fluids, Foley catheter for urine output monitoring
2. IV Heparin anticoagulation - Start immediately upon diagnosis; prevents thrombus propagation; unfractionated heparin bolus (80 U/kg) then infusion (18 U/kg/hr). If hypercoagulable workup needed, draw samples before heparin.
3. Analgesia - IV opioids for pain
4. Position - Keep the limb dependent (slightly below heart level) to improve perfusion; avoid pressure on the limb
5. Protect the limb - Pad bony prominences; do not apply heat (increases metabolic demand in ischemic tissue)
6. Oxygen supplementation
7. Emergency vascular surgery referral

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Definitive Treatment - Based on Rutherford Class

Class I (Viable) and IIa (Marginally Threatened)

• Catheter-directed thrombolysis (CDT) is preferred as first-line
  • tPA (alteplase) or urokinase infused directly into the thrombus via catheter
  • Advantages over surgery: reduced endothelial trauma, more gradual complete lysis including branch vessels too small for embolectomy catheters, potentially lower reperfusion injury
  • Contraindications: recent stroke (<3 months), intracranial malignancy, brain surgery; relative contraindications include renal insufficiency, recent arterial puncture, coagulopathy, diabetic retinopathy, cardiac thrombus
• Percutaneous mechanical thrombectomy / thromboaspiration - Can be used as standalone or adjunct when thrombolysis is contraindicated; FDA-approved devices for acute lower extremity arterial thrombosis

Class IIb (Immediately Threatened)

• Emergency surgical revascularization (insufficient time for thrombolysis)
• Open embolectomy (if embolic etiology):
  • Vertical groin incision exposing the common femoral artery (CFA) and its bifurcation
  • The location of the embolus at the femoral bifurcation is often apparent by a palpable proximal femoral pulse disappearing distally
  • A transverse arteriotomy over the bifurcation; Fogarty balloon catheter is passed to extract the thrombus
  • 5Fr or 6Fr catheter proximally into the infrarenal aorta; 3-4Fr distally into SFA and profunda
  • Good back-bleeding and antegrade bleeding confirm complete clot removal
  • Embolic material sent for culture and histology
  • Completion angiography to confirm adequate clot removal
  • The femoral approach is preferred due to the larger artery diameter reducing risk of arterial compromise at arteriotomy closure
• Bypass surgery - For in-situ thrombosis on atherosclerotic disease or failed bypass graft (embolectomy catheters cannot traverse calcified occlusions); if there are good distal vessels and suitable saphenous vein, surgical bypass is fast and durable

Class III (Irreversible)

• Primary amputation - When limb is non-viable (profound paralysis with rigor, fixed staining)
• Attempting revascularization risks reperfusion syndrome - massive release of myoglobin, potassium, and toxic metabolites causing cardiac arrhythmia, acute renal failure, and death

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Post-Revascularization Care

• After revascularization, ischemia-reperfusion releases oxygen free radicals, potassium, myoglobin, and lactate into circulation
• Monitor for compartment syndrome - pain on passive stretch, tense swollen compartments
• Fasciotomy of the 4 compartments of the leg should be performed prophylactically when ischemia time is >4-6 hours or there are signs of reperfusion injury

• Myoglobinuria / acute tubular necrosis - forced alkaline diuresis; monitor urine output >1 mL/kg/hr
• Hyperkalemia - cardiac monitoring, treat if K⁺ >6 mmol/L
• Metabolic acidosis - bicarbonate infusion
• Cardiac arrhythmias - especially if underlying AF

• Anticoagulation - Long-term warfarin (target INR 2-3) if embolic cause; direct oral anticoagulants if AF confirmed
• Treat underlying cause - Rate/rhythm control for AF, antiplatelet therapy for atherosclerosis
• Risk factor modification - Stop smoking, statin therapy, control hypertension/diabetes
• Surveillance imaging - Duplex ultrasound follow-up of revascularized segment

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Summary Algorithm

Suspected Acute Femoral Artery Occlusion
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  IV Heparin + Analgesia + Resuscitation
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  Clinical Assessment (6 Ps) + Doppler
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    Rutherford Classification
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  ┌────────────────────────────────┐
  │ Class I / IIa                 │ → Imaging (CTA/arteriography) → Thrombolysis or Endovascular
  │ Class IIb                     │ → Emergency Surgery (Embolectomy/Bypass)
  │ Class III (Irreversible)      │ → Amputation
  └────────────────────────────────┘
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  Post-op: Monitor for Compartment Syndrome, Reperfusion Injury
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  Long-term anticoagulation + Treat underlying cause

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Recent Evidence

• Abuajamieh et al., J Vasc Surg 2026 (PMID: 41232816) - Compared endovascular vs. open surgery in ALI; meta-analysis of current data
• Cosarca et al., Medicina 2025 (PMID: 40428785) - Compared thrombolytic therapy vs. open surgical intervention; no clear superiority of either for 30-day limb salvage or mortality, consistent with prior RCT data
• Abouzid et al., Prog Cardiovasc Dis 2025 (PMID: 38981532) - Endovascular therapy vs. surgical revascularization for critical limb-threatening ischemia

These confirm the established textbook guidance that no single modality is universally superior - treatment choice must be individualized based on ischemia severity, anatomical factors, and patient fitness.

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Dissecting Aneurysm of the Aorta (Aortic Dissection)

Definition

Note: The term "dissecting aneurysm" is somewhat a misnomer since the aorta need not be aneurysmal for dissection to occur, but the term persists clinically.

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Pathology

• Extend distally - as far as the iliac and femoral arteries
• Extend retrogradely - toward the heart, causing AR, hemopericardium, tamponade
• Rupture externally through the adventitia - causing massive hemorrhage or cardiac tamponade
• Re-enter the true lumen distally through a second tear - creating a "double-barrelled" aorta

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Predisposing Conditions / Etiology

Primary Risk Factors

Dissection is unusual in the presence of heavy atherosclerosis because medial fibrosis inhibits propagation of the dissecting hematoma.

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Classification

Stanford Classification (Clinically Most Useful)

DeBakey Classification

Temporal Classification

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Clinical Features

Cardinal Symptom: Pain

• Sudden onset, severe, tearing or ripping quality (described as the worst pain of their life)
• Associated with diaphoresis
• Location varies by type:
  • Type A: Anterior chest, substernal
  • Type B: Interscapular back pain, between the shoulder blades
• Pain characteristically migrates as the dissection propagates distally

Signs from Branch Vessel Occlusion

Signs from Retrograde Dissection (Type A)

• Aortic regurgitation (AR) - present in >50% of Type A; bounding pulses, wide pulse pressure, diastolic murmur along right sternal border
• Hemopericardium / cardiac tamponade - pulsus paradoxus, hypotension, JVP elevation, muffled heart sounds (Beck's triad)
• Acute MI - if coronary ostium involved

Signs from Compression of Adjacent Structures

Blood Pressure Findings

• Hypertension is most common
• Hypotension - suggests tamponade, AR, or rupture; ominous sign
• Pulse deficit - absent or diminished pulse in one arm or leg (due to occlusion of the artery of origin)
• Blood pressure differential between arms (>20 mmHg) - highly suggestive

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Investigations

Immediate Bedside

• Blood pressure in both arms - differential BP >20 mmHg is significant
• 12-lead ECG - critical to exclude acute MI; usually normal or shows LVH; inferior ST elevation if right coronary ostium involved
• Pulse oximetry, both limbs
• Chest auscultation - diastolic murmur of AR

Blood Tests

• FBC, urea, creatinine, electrolytes - baseline; renal involvement
• Cardiac troponin - may be elevated if coronary involvement; helps differentiate from MI (but does NOT exclude dissection)
• D-dimer - typically very elevated (>500 ng/mL) in acute dissection; a normal D-dimer has high negative predictive value to exclude dissection in low-risk patients
• Cross-match and group-and-save - for surgery preparation
• LFTs, amylase - if mesenteric involvement suspected
• Coagulation screen - disseminated intravascular coagulation possible

Chest X-Ray Findings

• Widened superior mediastinum (>8 cm or >25% of chest width) - most important sign; seen in ascending aortic dissections
• Abnormal aortic contour - loss of the aortic knuckle
• Pleural effusion (usually left-sided) - typically serosanguineous; not indicative of rupture unless accompanied by hypotension and falling Hct
• Tracheal/oesophageal deviation
• Normal in 10-20% of cases - cannot exclude dissection

Definitive Imaging

• Double-barrelled aortic lumen with intimal flap
• True lumen (smaller, high density) vs false lumen (larger, lower attenuation)
• Extent of dissection, involvement of branch vessels
• Pleural/pericardial effusion, mediastinal hematoma

• Dilated aortic lumen
• Linear, mobile echogenic structure (intimal flap) with motion different from aortic wall
• Different color Doppler flow patterns in true vs false lumen
• AR severity, pericardial effusion

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Management

Immediate Resuscitation (All Types)

1. Admit to ICU for continuous hemodynamic monitoring (arterial line, central line, Foley catheter)
2. IV access - large bore, two sites
3. Analgesia - IV morphine/opioids (reduces sympathetic drive)
4. Blood pressure control - the cornerstone of initial medical therapy
5. Oxygen supplementation
6. Cross-match blood, alert cardiothoracic surgery immediately
7. NPO (nothing by mouth) - anticipate surgery

Blood Pressure and Heart Rate Control

• Esmolol (preferred - short-acting, titratable): Bolus 500 mcg/kg IV, then infusion 0.05-0.2 mg/kg/min
• Metoprolol IV: 5 mg q5 min, up to 15 mg
• Propranolol IV: 1 mg q3-5 min
• Labetalol (alpha + beta blocker): 20 mg IV bolus q10 min; long half-life of 4-6 hours makes it less titratable but acceptable

Rationale: Beta-blockers MUST precede vasodilators. Vasodilators given first cause reflex tachycardia, which WORSENS dP/dt and propagates the dissection.

• Sodium nitroprusside: highly titratable, rapid-acting; infusion 0.5-10 mcg/kg/min
• Nicardipine or clevidipine (calcium channel blockers): alternatives if beta-blockers contraindicated
• Diltiazem/Verapamil: IV mixed calcium channel blockers if neither beta-blockers nor nitroprusside can be used

Contraindicated: Hydralazine, other direct vasodilators as monotherapy - increase hydraulic shear and heart rate, propagating dissection.

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Type A (Ascending) Dissection - EMERGENCY SURGERY

• Excision of the intimal flap at the site of entry tear
• Obliteration of the false lumen
• Interposition graft placement (Dacron tube graft)
• If aortic valve disrupted: Aortic valve repair or composite valve-graft replacement (Bentall procedure with aortic root replacement)
• Reimplantation of coronary arteries if root involved

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Type B (Descending) Dissection - Complication-Driven Approach

Uncomplicated Type B

• Medical therapy alone - initial treatment of choice
• BP and HR targets as above, continued parenterally then converted to oral therapy
• In-hospital mortality: ~12%
• Close monitoring for complications

Complicated Type B - TEVAR or Surgery

• Persistent/refractory pain (suggests propagation)
• Uncontrolled hypertension despite maximal medical therapy
• Progression of dissection (expansion)
• Branch vessel ischemia (bowel, renal, limb)
• Impending or frank rupture
• Rapid aortic expansion (>10 mm/year or diameter >6 cm)

• First-line for complicated Type B (preferred over open surgery)
• Stent graft covers the entry tear, seals the false lumen, promotes false lumen thrombosis
• Reduces morbidity/mortality significantly vs open surgery (open surgery for Type B: mortality >50%)
• Dynamic obstruction (true lumen collapse): TEVAR restores true lumen
• Static obstruction of branch vessels: Direct stenting of the compromised vessel
• Intimal flap fenestration: Creates communication between true and false lumen

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Long-Term Management (All Types)

1. Antihypertensive therapy: Lifelong; beta-blockers + ACE inhibitors/ARBs + calcium antagonists; target BP <120/80 mmHg
2. Risk factor control: Smoking cessation, lipid management, glycaemic control
3. Imaging surveillance: Follow-up CT/MRI at 1 month, 6 months, 12 months, then annually; monitor for aneurysmal expansion of false lumen (20-50% of Type B patients develop aneurysmal dilatation within 1-5 years)
4. Activity restriction: Avoid strenuous isometric exercise, weightlifting
5. Genetic counselling: If connective tissue disorder suspected (Marfan, Loeys-Dietz, Ehlers-Danlos)

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Acute Aortic Syndrome Spectrum

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Key Differentiating Points vs. Acute MI

Critical: Do NOT give thrombolytics if aortic dissection is suspected - it is catastrophic and causes massive haemorrhage.

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Summary: Management Algorithm

Suspected Aortic Dissection
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  IV Analgesia + IV Beta-blocker → Target HR <60-80 bpm
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  Add vasodilator → Target SBP <120 mmHg
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  CT Angiography (urgent)
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     ┌─────────────────────┐
     │ TYPE A              │ → Emergency cardiothoracic surgery
     │ (Ascending involved)│
     ├─────────────────────┤
     │ TYPE B (Descending) │
     │ - Uncomplicated     │ → Medical therapy + ICU monitoring
     │ - Complicated       │ → TEVAR (or open surgery if TEVAR not feasible)
     └─────────────────────┘
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  Long-term: Antihypertensives + Annual imaging surveillance

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Recent Guidelines (2024-2026)

• 2022 ACC/AHA Guideline for aortic disease (PMID: 37389507) - comprehensive North American guidance
• 2024 ESC Guidelines for peripheral arterial and aortic diseases (PMID: 39210722) - European standard of care
• 2026 ESVS Guidelines on descending thoracic and thoraco-abdominal aortic diseases (PMID: 41448425) - the most recent, published February 2026

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