Peripheral Arterial Disease - Presentation, Investigation & Therapy Flashcards
What are the main and less common causes of CLI (critical limb ischaemic) in the lower limbs?
(3)
Main: atherosclerosis of arteries
Less common: vasculitis, Buerger’s disease
What are the risk factors associated with CLI?
6
Male Age Smoking Hypercholesterolaemia Hypertension Diabetes
The sequence of progression with atherosclerosis is as follows:
Initial lesion - fatty streak - intermediate lesion - atheroma - fibroatheroma - complicated lesion
What happens in the initial lesion stage?
(3)
- macrophage infiltration
- isolated foamy cells
- growth mainly by lipid addition
The sequence of progression with atherosclerosis is as follows:
Initial lesion - fatty streak - intermediate lesion - atheroma - fibroatheroma - complicated lesion
What happens in the fatty streak stage?
(1)
- mainly just intracellular lipid accumulation
The sequence of progression with atherosclerosis is as follows:
Initial lesion - fatty streak - intermediate lesion - atheroma - fibroatheroma - complicated lesion
What happens in the intermediate lesion stage?
(2)
- continued intracellular lipid accumulation
- small extracellular lipid pools
The sequence of progression with atherosclerosis is as follows:
Initial lesion - fatty streak - intermediate lesion - atheroma - fibroatheroma - complicated lesion
What happens in the atheroma stage?
(2)
- continued intracellular lipid accumulation
- lipid core begins to develop from extracellular lipids
The sequence of progression with atherosclerosis is as follows:
Initial lesion - fatty streak - intermediate lesion - atheroma - fibroatheroma - complicated lesion
What happens in the fibroatheroma stage?
(3)
- there is now a single or multiple lipid core
- smooth muscle and collagen increases (main growth mechanism)
- fibrous/calcific cap formed around lipid core
The sequence of progression with atherosclerosis is as follows:
Initial lesion - fatty streak - intermediate lesion - atheroma - fibroatheroma - complicated lesion
What happens in the complicated lesion stage?
(3)
- surface defect
- haematoma/haemorrhage
- thrombosis
- rupture/embolism
What is stage I of the Fontaine Classification for chronic ischaemia?
Asymptomatic, incomplete blood vessel obstruction.
What is stage II of the Fontaine Classification for chronic ischaemia?
Mild claudication pain in limb.
What are the subclassifications of stage II?
IIA: claudication >200m walking
IIB: claudication <200m walking
What is stage III of the Fontaine Classification for chronic ischaemia?
Rest pain, mostly in the feet.
What is stage IV of the Fontaine Classification for chronic ischaemia?
Necrosis and/or gangrene of the limb.
Which stage(s) are considered to be CLI?
III & IV
What information should be gathered surrounding leg pain during a history?
Claudication:
- exercise tolerance
- effect of incline
- change over time
- relieved by rest
- location/bilateral
- character
Rest pain:
- character
- relief factors
What things should be considered/asked about during a past medical history for leg ischaemia?
(4)
- hypertension
- DM
- hypercholesterolaemia
- surgeries
What things should be considered/asked about during the social history for leg ischaemia?
(2)
- occupation
- smoking
What is an important step to take before carrying out a leg examination of suspected ischaemia?
expose both legs
What should you inspect for during a leg examination?
3
ulceration
pallor
hair loss
What should you palpate/feel for during a leg examination? (4)
Where should you start on the leg?
(3)
Start at the toes, comparing both sides
Temperature
Capillary refill time
Peripheral sensation
Pulses – start at the aorta
What should you auscultate for during a leg examination?
2
Using a hand held doppler, check the dorsalis pedis and posterior tibial pulses
Doppler auscultation over the dorsalis pedis will show what in healthy, more unhealthy and very unhealthy arteries?
healthy- triphasic nature
unhealthy- biphasib
very unhelathy- monophasic
What are the specialist tests carried out for chronic limb ischaemia?
(2)
Ankle Brachial Pressure Index
Buerger’s test
How do you calculate ABPI (ankle brachial pressure index)?
What is the normal threshold i.e. what does a low reading indicate?
ankle pressure divided by brachial pressure
threshold = 0.5
<0.5 = CLI
the smaller the value, the more severe
What does a ABPI of 1+ indicate?
symptom free
What does a ABPI of 0.95-0.5 indicate?
intermittent claudication
What does a ABPI of 0.5-0.3 indicate?
rest pain
What does a ABPI of <0.2 indicate?
gangrene/ulceration
Describe Buerger’s test.
4
- elevate legs
- pallor < 20 degrees = severe ischaemia (CLI)
- legs over edge of bed
- slow colour regain/dark red colour = CLI
What imaging techniques would be used to investigate potential CLI?
(3)
- duplex ultrasound
- MRA/CTA
- digital subtraction angiography
Patients with peripheral arterial disease (PAD) are considered at the same high risk level and should be managed in the same way as what group of patients?
patients with coronary artery disease (CAD)
What is the best medical/pharmacological therapy for CLI?
- antiplatelets
- statin
What do statins do?
3
- Inhibits platelet activation/thrombosis
- inhibits endothelial and inflammation activation
- prevents plaque rupture/embolisation
What are other conservative ways to manage CLI?
4
- BP control <140/85
- smoking cessation
- diabetic control
- exercise
What is the BP target for CLI?
<140/85
What is the best treatment for moderate CLI?
- medical therapy
- conservative therapy
What is the best treatment for severe CLI?
surgery
What are the open surgery procedures performed in CLI?
2
- by-pass
- endarterectomy
What is an endarterectomy?
open up artery, clean the plaque, and lightly stitch it back to avoid further narrowing
What are the endovascular surgical procedures performed in CLI?
Balloon angioplasty
Stent placement
Atherectomy
What is an atherectomy?
- minimally invasive endovascular surgery technique for removing atherosclerosis from blood vessels within the body.
What is an angioplasty?
- minimally invasive endovascular procedure used to widen narrowed or obstructed arteries or veins, typically to treat arterial atherosclerosis.
What is needed for a surgical bypass graft for CLI?
3
- inflow
- conduit
- outflow
What are the different types of conduits used during by-pass surgery?
(2)
- autologous: (vein from legs, arm)
- synthetic:(PTFE/Dacron)
What are the risks associated
with surgical bypass for CLI?
(6)
- bleeding
- infection
- DVT/MI/CVA/PE/LRTI
- damage to nearby v/a/n
- distant emboli
- graft failure
What is the aetiology of acute limb ischaemia?
5
- thrombus
- embolus
- dissection (e.g. carotid dissection)
- trauma (e.g. car accident)
- Acute aneurysm thrombosis (e.g. popliteal)
What can lead to an arterial embolus? (3)
What is this not the same as?
MI/AF/proximal atherosclerosis
DVT/PE
What are the clinical presentations of acute limb ischaemia?
6
- pain
- pallor
- pulse deficit
- paraesthesia (abnormal sensation)
- paralysis
- poikilothermia
N.b. always compare with contralateral limb
What information should be gathered in the history for acute limb ischaemia?
(5)
- cardiac history
- HPC: onset/duration
- PMH: chronic limb ischaemia?
- SH: risk factors
- functional status
What is compartment syndrome?
build up of pressure in muscle compartments
Describe the pathophysiology of compartment syndrome?
4
- pressure build = venous obstruction
- inflammation/oedema
- reduced arterial flow/muscle ischaemia
- ultimately this leads to renal failure (myogloulinaemia)
What are the signs of compartment syndrome?
2
- increase in creatine kinase
- tense/tender calf
What is the treatment process for acute compartment syndrome?
fasciotomy
- fascia is cut to relieve tension or pressure
to reduce loss of circulation to an area of tissue or muscle - limb-saving procedure
What is the treatment process for embolus formed in acute compartment syndrome?
embolectomy
What is the treatment process for thrombosis formed in acute compartment syndrome?
(2)
endovascular mechanical thrombectomy
open embolectomy +/- bypass
What is the management of acute limb ischaemia if the limb is not salvageable?
(2)
palliation
amputation
What is the pathophysiology of diabetic foot disease?
6
- Microvascular PAD
- Peripheral neuropathy
- Mechanical imbalance
- Foot deformity
- Minor trauma
- more susceptible to infection
How can diabetic foot disease be prevented?
4
- foot care
- foot protection
- prompt cand regular wound care of skin breaches
- effective glycaemic control
What would be the management plan for a diabetic foot disease?
- prevention
- effective wound care
- systemic antibiotics
- investigate for further disease
What further problems could a diabetic foot ulcer progress to?
(3)
osteomyelitis
gas gangrene,
necrotizing fasciitis
What would be the further management/treatment of a severe/complicated DFU?
- revascularisation
- amputation
What are the revascularising techniques for diabetic foot disease?
(2)
- Attempt distal crural angioplasty/stent
- Distal bypass
What adjunctive measures can be used to manage/treat diabetic foot disease?
i.e. other than medication/surgery
(4)
- dressings
- larval therapy (worms)
- negative pressure wound closure
- skin grafts
What are the sites for lower limb amputation?
6
- hip dislocation
- above knee
- below knee
- symes’
- trans-metatarsal
- digital (toes)