Limb ischaemia Flashcards
Cause of limb ischaemia
Atherosclerosis
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
Risk factors
Modifiable: • Smoking • HTN • Poor DM control • Hyperlipidaemia • Sedentary lifestyle
Non-modifiable • FH and PMH • Male • ↑ age • Genetic
Intermittent Claudication
- Cramping pain after walking a fixed distance
- Pain rapidly relieved by rest
- Calf pain = superficial femoral disease (commonest)
- Buttock pain = iliac disease
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
Leriche’s Syndrome
Atherosclerotic occlusion of abdominal aorta and iliacs
Triad:
- Buttock claudication and wasting
- Erectile dysfunction
- Absent femoral pulses
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
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
Buerger’s Angle
- ≥90: normal
- 20-30: ischaemia
- <20: severe ischaemia
Classification system for limb ischemia
Fontaine
Rutherford
Investigations for chronic limb ischaemia
Doppler Waveforms ABPI Walk test - maximum claudication distance Bloods Imaging
BP
CBG + HbA1c
Lipid profile
ECG
Abnormal doppler
- Mild stenosis: biphasic
* Severe stenosis: monophasic
Conservative Mx
Conservative: • ↑ exercise • Stop smoking • Wt. loss • Foot care • HTN, lipids, DM control - CVS risk reduction first line
Prognosis of chronic limb ischaemia
1/3 improve
1/3 stay the same
1/3 deteriorate
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
Indications for surgical reconstruction
- V. short claudication distance (e.g. <100m)
- Symptoms greatly affecting pts. QoL
- Pain at rest
Acute limb ischaemia time frame
Acute limb ischaemia <14d
• Acute on chronic: worsening symptoms and signs <14d
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
- Embolectomy
- Thrombolysis- if embolectomy unsuccessful
- 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