Acute + chronic limb ischaemia Flashcards
What is peripheral arterial disease?
narrowing or occlusion of the peripheral arteries, affecting blood supply to the lower limbs
Modifiable risk factors for peripheral arterial disease
smoking
diabetes
hypertension
hypercholesterolaemia
hyperhomocysteinaemia
CRP
Describe the Fontaine classification of peripheral arterial disease
1 = asymptomatic
2a = mild claudication
2b = moderate to severe (short distance) claudication
3 = ischaemic rest pain
4 = ulceration or gangrene
Symptoms of peripheral arterial disease
asymptomatic
intermittent claudication
exercise-induced muscle pain - calf, buttocks, thigh
worse walking uphill or hurrying
relieved by rest <10 mins
Describe sites of intermittent claudication and the associated arteries
Buttock + hip = aortoiliac disease
Thigh = aortoiliac or common femoral artery
Upper 2/3 of calf = superficial femoral artery
Lower 1/3 of calf = popliteal artery
Foot claudication = tibial or peroneal artery
What is Leriche syndrome?
severe atherosclerosis affecting the distal abdominal aorta, iliac arteries, and femoro-popliteal vessels
triad = claudication, absent femoral pulses, erectile dysfunction
Differential diagnoses for peripheral arterial disease
Vascular = aneurysm, limb trauma, radiation exposure, vasculitis, popliteal entrapment syndrome, chronic venous disease
Neurological pain = neurospinal (eg. disc disease, spinal stenosis tumour) or neuropathic (eg. DM, alcohol abuse)
Musculoskeletal = pain derived from bones, joints, ligaments, tendons and fascial elements of lower extremity
What are 3 symptoms of chronic limb threatening ischaemia? (CLTI)
Ischaemic rest pain - severe pain at rest due to inadequate oxygen perfusion
Ischaemic ulcer - formed at sites of increased focal pressure (malleoli, tips of toes, metatarsal heads, heels - usually dry + punctuate)
Gangrene - dry or wet
Describe dry gangrene
common in diabetic patients
develops when there is impaired blood flow to an area
tissue dries up - brown to purplish-blue to black in colour
infection not typically present
can lead to wet gangrene
Describe wet gangrene
liquefactive necrosis due to infection
tissue swells + blisters
wet because of pus
infection can quickly spread throughout body
Wet gangrene treatment
High dose IV abx
revascularisation, debridement +/- amputation
List 4 vascular investigations
duplex ultrasound
CT angiography
magnetic resonance angiography
contrast angiography
Management: asymptomatic patients of mild claudication (peripheral arterial disease)
lifestyle modification:
- smoking cessation
- exercise
- diet control
pharmacological:
- risk factor modification (control BP, diabetes, dyslipidaemias)
- antiplatelet therapy
- cholesterol lowering medication
Management: short distance claudication (peripheral arterial disease)
lifestyle modification:
- smoking cessation
- exercise
- diet control
pharmacological:
- risk factor modification (control BP, diabetes, dyslipidaemias)
- antiplatelet therapy
- cholesterol lowering medication
- Naftidrofuryl/Cilostazol
endovascular:
- angioplasty +/- stent placement
surgical:
- endarterectomy
- peripheral bypass graft (autologous vein/prosthetic)
What is angioplasty?
pressure controlled balloon inflation to fracture arterial plaque and remodel the artery
most effective for short focal stenoses without heavy calcification
Angioplasty complications
arterial puncture site haemorrhage
arterial rupture
dissection
distal embolisation
contrast-induced nephropathy
Complications of vascular surgery
bleeding
infection
distal embolisation
limb loss
heart/lung/kidney complications
DVT
death
Chronic limb threatening ischaemia treatment
lifestyle modification
pharmacological therapy
wound care (conservative management)
revascularisation (to reduce rest pain or for the management of tissue loss/gangrene in order to avoid amputation)
amputation
List 5 common amputation sites
Toe amputation - removal of toe through proximal phalanx
Ray amputation - removal of toe through metatarsal bone
Trans-metatarsal amputation - amputation of all the toes through mid-metatarsal bones
Below knee amputation - through tibia 10-12cm distal to tibial tuberosity, through fibula 2cm proximal to tibia
Above knee amputation - at mid-femoral level >15cm from tibial plateau
Amputation complications
failure of wound to heal
flap necrosis
wound infection
post-amputation pain (phantom limb pain)
stump haematoma
flexion contractures
psychological problems
What is acute limb ischaemia?
sudden decrease in limb perfusion that causes a potential threat to limb viability in patients who present within 2 weeks of the acute event
Aetiology of acute limb ischaemia
Embolus:
- AF
- MI
- Endocarditis
- Valvular disease
- Atrial myxoma
- Prosthetic valves
- Aneurysm
- Atherosclerotic plaque
Thrombosis:
- Vascular grafts
- Atherosclerosis
- Thrombosis of an aneurysm
- Entrapment syndrome
- Hypercoagulable state
- Low flow state
Trauma:
- Blunt
- Penetrating
- Iatrogenic
6 Ps of acute ischaemia
Pain
Pulselessness
Pallor
Paraesthesia
Paralysis
Poikilothermic (Perishingly cold)
What is the best diagnostic procedure in acute limb ischaemia?
CT angiography
- shows detailed arterial anatomy
- distinguishes between thrombosis and embolism
- allows definitive management plan to be made
Initial management of acute limb ischaemia
ABC
Analgesia
FBC
U&E
Baseline clotting profile
Heparin - immediate IV bolus followed by continuous heparin infusion
Complications of acute limb ischaemia
Compartment syndrome -reperfusion of ischaemic muscles can cause oedema and increased compartmental pressure
Reperfusion injury - products of cell death (eg. K+, phosphate, myoglobin) released into blood flow - can result in rhabdomyolysis, cardiac dysrhythmia, AKI, multiorgan failure and DIC
