2: Acute and Chronic Limb Ischaemia Flashcards
What causes peripheral arterial disease
atherosclerosis of arteries resulting in decreased limb perfusion
What are the 3 patterns of peripheral arterial disease
- Intermittent claudication
- Chronic limb ischaemia
- Peripheral limb ischaemia
What is critical limb ischaemia
Advanced limb-threatening form of chronic limb ischaemia
In which population is peripheral arterial disease more common
60-80y
What causes peripheral arterial disease
- Atherosclerosis of the arteries, reducing limb perfusion
2. Arterial clot from heart travels to occlude arteries
Why is there claudication in peripheral arterial disease
Stenosis of arteries results in decreased blood supply and oxygen to tissues. This causes ischaemia and release of adenosine which stimulates nociceptors causing pain sensation.
What are the two non-modifiable risk factors for peripheral arterial disease
Age
Family History
What is the most important factor for peripheral arterial disease
Smoking
What are 5 other modifiable risk factors of peripheral arterial disease
HTN Diabetes Hyperlipidaemia Coronary artery disease Obesity
What is intermittent claudication
buttock, calf or leg pain on walking a certain distance
Which artery is affected if claudication of the buttock
iliac
Which artery is affected if claudication of upper 2/3 of the calf
femoral
Which artery is affected if claudication of lower 1/3 of the calf
popliteal
What is leriche’s syndrome
occlusion at the aortic bifurcation of bilateral occlusion of common iliac arteries
What is the triad of symptoms seen in Leriche’s syndrome
- Erectile Dysfunction
- Buttock Claudication
- Absent femoral pulses
What is Buerger’s disease also known as
Thrombophlebitis Obliterans
In which population does thrombophlebitis obliterates present in
Young Heavy Smokers
What is use to classify peripheral arterial disease
Fontaine Classification
What is Stage I Fontaine Classification
Asymptomatic
What is Stage IIa Fontaine Classification
Pain on walking >200m
What is Stage IIb Fontaine Classification
Pain on walking <200m
What is Stage III Fontaine Classification
Pain at rest
What is Stage IV a Fontaine Classification
Dry necrosis
Trophic Disorders
What is Stage IVb Fontain Classification
Infection of necrotic tissue
Humid gangrene
What are 3 signs of arterial disease
- Pale
- Cold
- Atrophic skin
- Punched out, painful ulcers
Describe the appearance of an arterial ulcer
- small + deep lesion
- well-defined borders
- necrotic base
- occur @ pressure areas
- occur over long period
- little healing
What is Buerger’s angle
The angle at which the legs go pale on lifting them in PAD. Less than 20 degrees indicates critical ischaemia
What are the 3 ways to define critical ischaemia
- Ishaemic rest pain for more than two weeks
- ABPI <0.5
- Presences of ischaemic lesions or gangrene
What blood tests are indicated for peripheral arterial disease
- HbA1c
- U+Es
- FBC
- CRP/ESR
What additional blood tests are ordered for individuals <50y
Thrombophillia and homocysteine screen
What cardiovascular assessments are ordered for those with PAD
ECG
BP
What bedside test may be used for diagnose peripheral arterial disease
Ankle-brachial pressure index
What is a normal ABPI
1-1.2
What is ABPI in mild ischaemia
0.9-0.8
What is ABPI in moderate ischaemia
0.8-0.5
What is ABPI in severe ischaemia
<0.5
What ABPI indicates peripheral arterial disease
<0.9
What ABPI indicates critical limb ischaemia
<0.5
What does an ABPI of >1.2 indicate
calcified vessels
What is first-line imaging test for peripheral arterial disease
colour duplex US
What imaging test is used if intervention for peripheral arterial disease is being performed
MRI or CT angiography
What is first step in management of peripheral arterial disease
Risk Factor Modification
What are 4 elements of risk factor modification for peripheral arterial disease
- Anti-hypertensives
- Clopidogrel (75mg)
- Atorvostatin (80mg)
- Smoking cessation
What is the first step in medical management of peripheral arterial disease
Supervised exercise program
How is supervised exercise therapy suspected to work
improves collateral flow to tissues
How long should an individual do supervised exercise therapy for
2h a week for 3 months
What is second-line management for PAD
Naftidrofuryl Oxalate
When is naftidrofuryl oxalate offered
If supervised exercise program has failed and individual is un-fit or does not want surgery
What are the conditions for surgery in PAD
- Supervised exercise programs failed
- Risk factor modification has been discussed
- Or, critical ischaemia
What are the two main surgical options for PAD
- Bypass graft
2. Percutaneous transluminal angioplasty
When is percutaneous transluminal angioplasty used
When disease is limited to a single arterial segment
How does PTA work
Balloon is inflated which increases diameter of the vessel
When are bypass grafts used
Extensive atheromatous disease with good distal run-off
Which is better autologous vein grafts of prosthetic grafts
Autologous vein grafts are better if the knee is crossed
If peripheral arterial disease is caused by AF, how is it managed
Embolectomy
When is amputation considered
Any patient unsuitable for revascularisation when symptoms have resulted in gangrene or incurable sepsis
What can be given for phantom limb pain following amputation
Gabapentin
What classification system is used to predict the risk of amputation in PAD
WIFI
Outline the WIFI classification
Wound (ulcers)
Ischaemia (on ABPI)
FI: foot infection
What is the 5-year mortality rate of critical limb ischaemia
50%
What is the main complication of peripheral arterial disease
65% of individuals will have co-existing cerebral or coronary artery disease
What on a doppler indicates PAD
Peak systolic flow volume of more than 2 - indicates stenosis of >50%
What is done in 1-2d following amputation
- Stump covered with a bandage
- Individual is encouraged to touch their stump
- wheelchair used
What is done 3-5d post amputation
- individual should lie flat as possible for 1h + straighten hip
What is done 6-10d post amputation
pneumatic post amputation mobility aid (PPAM aid) used to mobilise
What is done 11-21 days post amputation
Transfer to amputee rehabilitation unit
Define acute limb ischaemia
Sudden decrease in limb perfusion that threatens limb viability
What are the 3 causes of acute limb ischaemia
- Thrombosis in situ
- Distal embolisation
- Trauma
What is the most common cause of acute limb ischaemia
Thrombosis in situ (60%)
Explain thrombosis in situ
Atheromatous plaque in the artery forms and ruptures. Thrombus forms on the plaque
What can embolism to cause acute limb ischaemia
AAA
AF
Post MI mural thrombus
Prosthetic heart valves
What trauma may result in acute limb ischaemia
Compartment syndrome
What are the 6P’s of acute limb ischaemia
- Painful
- Pulseless
- Perishingly Cold
- Pale
- Paraesthesia
- Paralysis
What is the classification system of acute limb ischaemia
Rutherford Classification System
In the Rutherford Classification System what is I
Viable
What is the prognosis of Class I
There is no immediate threat
Describe features in class I
- Motor - intact
- Sensory - intact
- Arterial doppler - present
- Venous doppler - present
What is Rutherford IIa
Marginally Threatened
What is the prognosis of Rutherford IIa
Salvageable with prompt treatment
What are the features of Rutherford IIa
- Motor - minimal weakness
- Sensory - Intact
- Arterial doppler - inaudible
- Venous doppler - audible
What is the state of Class IIb
Immediate Threat
What is the prognosis of class IIb
Salvageable with immediate treatment
Explain the features of class IIb
- Motor - mild loss
- Sensory - mild loss
- Arterial - inaudible
- Venous - audible
What is Rutherford class III
Irreversible
What is the prognosis of class III
Major, permanent, tissue loss and nerve damage
What are the features of Rutherford class III
- Motor - profound loss
- Sensory - profound loss
- Arterial - inaudible
- Venous - inaudible