1. Endothelial injury 2. Chronic inflammation - Lipid-laden foam cells produce GFs, cytokines and ROS - lymphocyte and SMC recruitment 3. SM proliferation: conversion of fatty streak to atherosclerotic plaque with fibrous cap

Atherosclerotic occlusion of abdominal aorta and iliacs Triad: - Buttock claudication and wasting - Erectile dysfunction - Absent femoral pulses

- ≥90: normal - 20-30: ischaemia - <20: severe ischaemia

Mild stenosis: biphasic Severe stenosis: monophasic

Limb ischaemia Flashcards by Anmol Landa

Cause of limb ischaemia

Atherosclerosis

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Atherosclerosis

Endothelial injury
Chronic inflammation
- Lipid-laden foam cells produce GFs, cytokines and ROS
- lymphocyte and SMC recruitment
SM proliferation: conversion of fatty streak to atherosclerotic plaque with fibrous cap

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Risk factors

Modifiable:
• Smoking
• HTN
• Poor DM control
• Hyperlipidaemia
• Sedentary lifestyle

Non-modifiable
• FH and PMH
• Male
• ↑ age
• Genetic

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Intermittent Claudication

Cramping pain after walking a fixed distance
Pain rapidly relieved by rest
Calf pain = superficial femoral disease (commonest)
Buttock pain = iliac disease

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Critical Limb Ischaemia

Ankle pressure < 50mmHg and either:

Pain at rest requiring analgesia for 2+ wks
Especially at night
Usually felt in the foot
Pt. hangs foot out of bed
Ulceration or gangrene

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Leriche’s Syndrome

Atherosclerotic occlusion of abdominal aorta and iliacs

Triad:

Buttock claudication and wasting
Erectile dysfunction
Absent femoral pulses

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Buerger’s Disease

Thromboangiitis Obliterans
• Young, male, heavy smoker
• Acute inflammation and thrombosis of arteries and
veins in the hands and feet → ulceration and
gangrene - black fingers

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Signs if limb ischaemia

Loss of pulses and increased cap refill time
Ulcers: painful, punched-out, on pressure points
Onycholysis
Skin: cold, pallor, atrophy, absent hair
Venous guttering
Muscle atrophy
↓ Buerger’s Angle
+ve Buerger’s Sign

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Buerger’s Angle

≥90: normal
20-30: ischaemia
<20: severe ischaemia

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Classification system for limb ischemia

Fontaine

Rutherford

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Investigations for chronic limb ischaemia

Doppler Waveforms
ABPI
Walk test - maximum claudication distance
Bloods 
Imaging

BP
CBG + HbA1c
Lipid profile
ECG

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Abnormal doppler

Mild stenosis: biphasic

* Severe stenosis: monophasic

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Conservative Mx

Conservative:
• ↑ exercise 
• Stop smoking
• Wt. loss
• Foot care
• HTN, lipids, DM control - CVS risk reduction first line

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Prognosis of chronic limb ischaemia

1/3 improve
1/3 stay the same
1/3 deteriorate

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Medical Mx for chronic limb ischaemia

Lifestyle advice
Stain
Antiplatelets: aspirin/ clopidogrel
Optimise DM
Analgesia: may need opiates
Supervised exercise programme

Surgery:
• Percutaneous Transluminal Angioplasty ± stenting
• Bypass graft
• Amputation if can’t revascularise

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Indications for surgical reconstruction

V. short claudication distance (e.g. <100m)
Symptoms greatly affecting pts. QoL
Pain at rest

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Acute limb ischaemia time frame

Acute limb ischaemia <14d

• Acute on chronic: worsening symptoms and signs <14d

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Chronic limb ischaemia time frame

Ischaemia for >14d

Severity

Incomplete: limb not threatened

Complete: limb threatened
- Loss of limb unless intervention w/i 6hrs

Irreversible: requires amputation

Causes of acute ischaemia

• Thrombosis (often incomplete)
- Previously stenosed vessel with plaque rupture

• Embolism (Often complete ischaemia)

Valve disease
Iatrogenic
Cholesterol in long bone fracture
Paradoxical (venous via PFO)
Graft / stent occlusion
Trauma
Aortic dissection

6 Ps of ischaemic limb

Pain 
Pulseless 
Perishing with cold 
Pallor 
Paralysis 
Paraesthesia

Thrombosis

Onset: hrs - days 
Severity: Less severe due to collaterals
Claudication Hx: Present 
Contralateral pulses: Absent 
Diagnosis: Angiography 
Tx: Thrombolysis

Embolism

Onset: Sudden
Severity: Profound ischaemia
Embolic source: Often AF
Claudication hx: Absent
Contralateral pulses: present
Diagnosis: Clinical
Tx: Bypass surgery

Investigations for acute limb ischaemia

Blood
- FBC, U+E, INR, G+S
- CK
•  ABG - lactate
• ECG
• Imaging
- CXR - PE
- Duplex doppler
- CT angio
- CT arteriogram if surgery

Immediate Mx of acute limb ischaemia

``` Senior help • NBM • Rehydration: IV fluids • Analgesia: morphine + metoclopramide • Abx: co-amoxiclav if signs of infection • Unfractionated heparin IV ``` • Complete occlusion? - Yes: urgent surgery: embolectomy or bypass - No: angiogram + observe for deterioration

Angiography

Not performed if there is complete occlusion • If incomplete occlusion, pre-op angio will guide any distal bypass.

Embolus Mx

1. Embolectomy 2. Thrombolysis- if embolectomy unsuccessful 3. Emergency reconstruction or amputation

Embolectomy

- Wire fed through embolus - Catheter fed over the top - Balloon inflated and catheter withdrawn, removing the embolism. - Adequacy confirmed by on-table angiography

Post-embolectomy

• Anticoagulate: heparin IV → warfarin • ID embolic source: ECG, echo, USS aorta, fem and popliteal artery

Complications of embolectomy

• Reperfusion injury - Local swelling can cause compartment syndrome - Acidosis and arrhythmia secondary to ↑K - ARDS - GI oedema → endotoxic shock • Chronic pain syndromes

Window for acute limb ischaemia surgery

6 hours

Acute limb ischaemia

sudden decrease in limb perfusion that threatens the viability of the limb caused by Complete or partial occlusion of the arterial supply

Irreversible limb ischaemia

Mottled, non-blanching appearance with hard woody muscles, requires urgent amputation or palliation

Long Term Management of acute limb ischaemia

Reduction of the cardiovascular mortality risk - regular exercise - smoking cessation - weight loss - antiplatelet - low - dose aspirin

Complications of acute limb ischaemia

Compartment syndrome - hyperkalaemia - acidosis - AKI due to myoglobin release Reperfusion injury

Risk factors for chronic limb ischaemia

``` Smoking Diabetes mellitus Hypertension Hyperlipidaemia Increasing age Family history Obesity and physical inactivity ```

Stages of chronic limb ischaemia

Stage I Asymptomatic Stage II Intermittent claudication Stage III Ischaemic rest pain Stage IV Ulceration or gangrene, or both

Chronic limb ischaemia presentation

Intermittent claudication

Critical Limb Ischaemia clinical features

Ischaemic rest pain for greater than 2 weeks, requiring opiate analgesia Presence of ischaemic lesions or gangrene ABPI less than 0.5

Examination findings of critical Limb Ischaemia

``` Pale Cold Weak or absent pulses Limb hair loss Skin changes - atrophic skin, ulceration, or gangrene Thickened nails ```

Critical Limb Ischaemia Ix

``` Vascular exam Obs Bloods - FBC, U+Es, clotting, G+S, lipids, HbA1c ABG - lactate ECG Doppler USS Ct angiogram ```

Chronic limb ischaemia complications

Sepsis Acute-on-chronic ischaemia, Amputation Reduced mobility and quality of life

Classification of acute limb ischaemia

Rutherford Class I - viable Class II - Marginally threatened Class III - immediately threatened Class IV - irreversible