29. Arterial Diseases of Limbs Flashcards
Where is the aortic pulse best felt?
- above umbilicus
- use two hands to feel for pulsation vs expansion
Where is the common femoral artery best felt?
- mid-inguinal point
- half way between the anterior superior iliac spine ad the pubic synthesis
Where is the popliteal artery pulse best felt?
-use both hands to feel deep in the popliteal fossa (leg relaxed into your hands)
Where is the posterior tibial pulse best felt?
- half way between medial malleolus (ankle) and the achilles tendon
Where is the dorsalis pedis pulse best felt?
-lateral to the extensor hallucis longus tendon (halfway between first and second toe)
What type of disease is chronic limb ischaemia?
- atherosclerotic disease of the arteries supplying the lower limb
- same disease process as coronary and carotid atherosclerotic disease
- systematic disease (occurs over time)
What is chronic limb ischaemia less commonly known as? (2)
- vasculitis
- Buerger’s disease
What are the main risk factors for chronic limb ischaemia? (6)
- male
- age (older)
- smoking
- hypercholesterolaemia
- hypertension
- diabetes
What are the different sequences/stages of progression in atherosclerosis that lead to chronic limb ischaemia? (6)
- Initial lesion
- fatty streak
- intermediate lesion
- atheroma
- fibroatheroma
- complication lesion
What is initial lesion? (in atheroma formation)
- histologically normal
- macrophage infiltration
- isolated foam cells
- forms from 1st decade
- growth mainly by lipid addition
What is fatty streak? (in atheroma formation)
- mainly intracellular lipid accumulates
- forms from 1st decade
- growth mainly by lipid addition
What is intermediate lesion?( in atheroma formation)
- intracellular lipid accumulation
- small extracellular lipid pools
- forms from 3rd decade
- growth mainly by lipid addition
What is atheroma? (in atheroma formation)
- intracellular lipid accumulation
- core of extracellular lipid
- forms from 3rd decade
- growth mainly by lipid addition
What is fibroatheroma? (in atheroma formation)
- single or multiple lipid cores
- fibrotic/calcific layers (cap)
- forms from 4th decade
- increased smooth muscle and collagen increases
What is a complication lesion? (in atheroma formation)
- surface defect
- haematoma-haemorrhage
- thrombus
- forms from 4th decade
- thrombosis and/or haematoma
From which stage of atheroma formation does the clinical presentation begin at? (symptoms)
from atheroma formation stage (includes fibroatheroma and complicated lesion)
What classification method is used to describe the chronic limb disease staging?
Fontaine Classification
What is Stage 1 Fontaine Classification for chronic limb ischaemia?
- asymptomatic
- incomplete blood vessel obstruction
What is Stage 2 Fontaine Classification for chronic limb ischaemia?
- mild claudication pain in limb
- Stage 2A: claudication when walking a distance of greater than 200m
- Stage 2B: claudication when walking a distance of less than 200m
What is Stage 3 Fontaine Classification for chronic limb ischaemia?
- rest pain mostly in feet
- due to obstruction in arteries (claudication), cramping in feet
What is Stage 4 Fontaine Classification for chronic limb ischaemia?
- necrosis and/or gangrene of the limbs
- tissue starts dying (very bad)
What are the critical features of patient history which should be identified? (3)
- CLAUDICATION: exercise tolerance, effect of incline, change over time, relief at rest, where in leg, type of pain, bilateral, muscle requires more blood due to artery obstruction, leg cramping
- REST PAIN: type of pain, relieving factors, gravity only pushes blood into feet
- TISSUE LOSS: duration, history of trauma, peripheral sensation, reduced sensation
What are the risk factors for chronic limb ischaemia? (4)
- past medical history
- diabetes history
- social history
- occupational history
What are clinical signs on INSPECTION examination indicating chronic limb ischaemia? (3)
- ulceration (tissue loss)
- pallor (unhealthy pale)
- hair loss
(compare both legs)
What 3 types of examination need to be done to detect chronic limb ischaemia?
- inspection
- palpation/feel
- auscultation
What needs to be done on PALPATION examination indicating chronic limb ischaemia? (4)
- capillary refill time
- temperature
- pulses (start at aorta)
- peripheral sensation (particularly in diabetics)
What need to be done on AUSCULTATION examination indicating chronic limb ischaemia?
- dorsalis pedis and posterior tibial pulses checked
to estimate blood flow in these areas
What 2 special tests can also be done to confirm chronic limb ischaemia?
- Ankle Brachial Pressure Index
2. Buerger’s test
What is done for ankle brachial pressure index test?
Division of ankle pressure over brachial pressure which indicates staging of disease
What are 4 stages found following an ankle brachial pressure index test?
- symptoms free (1 or more)
- intermittent claudication (0.95-0.5)
- rest pain (0.5-0.3)
- gangrene and ulceration (<0.2)
What is Buerger’s test?
- elevate legs and check for pallor and Buerger’s angle (<20 degrees) showing severe ischaemia
- hang feet over edge of bed; slow to regain colour or dark red colour (hyperanaemic sunset foot)
- All capillaries in foot open (in normal foot only 1/3 do), autoregulation is lost
What best medical therapy options are there for management of chronic limb ischaemia?
- antiplatelet
- statin
- BP control
- smoking cessation
- exercise
- diabetic control
How does antiplatelet therapy help with chronic limb ischaemia? (2)
- reduces risk of revascularisation
- reduces cardiovascular and all cause mortality
How does statin therapy help with chronic limb ischaemia? (3)
- inhibits platelet activation and thrombosis
- inhibits endothelial and inflammation activation
-prevent plaque rupture
(not only lowers cholesterol)
What is the target BP for chronic limb ischaemia patients?
< 140/ 85
How does smoking cessation help with chronic limb ischaemia?
excess risk of cardiovascular disease diminishes within 4-6 years
How does exercise help with chronic limb ischaemia?
150% improvement in walking time
How does diabetic control help with chronic limb ischaemia?
- 10% of peripheral arterial disease patients are undiagnosed diabetics
- tight glycaemic control prevents microvascular disease
What management option is chosen for patients with mild and moderate chronic limb ischaemia symptoms? (e.g. claudication)
best medical therapy only
What management options are chosen for patients with severe chronic limb ischaemia symptoms? (e.g. pain at rest) (3)
- best medical therapy
- angioplasty/stenting
- surgical bypass
What management options are chosen for patients with critical chronic limb ischaemia? (e.g. gangrene, ulceration, tissue loss) (4)
- best medical therapy
- angioplasty/stenting
- endovascular reconstruction
- surgical bypass
What main imaging investigations need to be done to diagnose chronic limb ischaemia?
- duplex (ultrasound)
- CT angiography (CTA) and magnetic resonance angiography (MRA)
- Digital Subtraction angiogram (fluoroscopy technique)
What are the pros for Duplex imaging? (2)
- dynamic
2. no radiation or contrast needed
What are the cons for Duplex imaging? (2)
- not good in abdomen
2. operator dependent and time consuming
What are the pros for CTA/MRA (CT angiography and magnetic resonance angiography) imaging? (2)
- detailed; allows effective treatment planning
2. first line according to NICE
What are the cons for CT/MRA imaging? (2)
- contrast and radiation
2. can overestimate calcification and difficulty in low flow states
What are 2 main function of angiography?
- for diagnostic reasons
- to insert stens and balloons during angioplasty
What 3 common surgical bypasses are made to treat chronic limb disease?
- Iliac angioplasty (crossover graft between r. and l. iliac arteries)
- aortobifemoral bypass graft (from aorta to both femorals)
- axillobifemoral bypass graft (from axillary artery into femoral arteries)
What 3 things does a surgical bypass always require?
- Inflow
- a conduit (autologous; veins from legs, arms, synthetic etc)
- outflow
What are the general complications for surgical bypass? (10)
- bleeding
- wound infection
- pain
- scarring
- DVT
- PE (pulmonary embolism)
- MI
- cerebrovascular accident (stroke)
- LRTI: lower resp. tract infection
- death
What are the technical complications for surgical bypass? (3)
- damage to nearby vein, artery or nerve
- distal emboli
- graft failure (stenosis, occlusion)
What are the re-intervention rates following a surgical bypass?
18-39% (1/3 approx)
In which lower limb locations can amputations be performed in? (8)
- hindquarter
- hip disarticulation
- above knee
- through knee
- below knee
- symes (at ankle)
- transmetatarsal
- digit (through toes)
What is acute limb ischaemia caused by/ pathophysiology? (5)
- arterial embolus: following MI, atrial fibrillation, proximal atherosclerosis (NOT DVT or PE)
- thrombosis; usually of previously diseased artery
- trauma
- dissection
- acute aneurysm thrombosis e.g. popliteal
Define embolus.
EMBOLI: blood clot, air bubble, piece of fatty deposit or other object which has been carried in bloodstream to lodge in a vessel and cause embolism
Define thrombus.
THROMBUS: blood clot formed in situ within vascular system of body and impeding blood flow
What history needs to be taken to diagnose acute limb ischaemia? (5)
- history of chronic limb ischaemia
- risk factors for chronic limb ischaemia
- cardiac history
- onset/duration of symptoms
- functional status and social history
How should acute limb ischaemia be defined as in simple terms?
sudden lack of blood flow to the limb
What is the presentation of acute limb ischaemia? (6 Ps)
- pain
- pallor
- perishingly cold
- paraesthesia (tingling/ numbness/ pricking/burning)
- paralysis
- pulsesless
What are the chances of resuscitating an ischaemic leg?
Very slim; most likely will not be fully functional again
What is compartment syndrome?
- increased pressure in body compartment which contains muscle and nerves
- most commonly occurs in legs or arms
- acute (injury/trauma) or chronic (exercise-induced) exist
What pathophysiology occurs in compartment syndrome? (5)
- muscle ischaemia
- inflammation
- oedema
- venous obstruction
- tender and tense calf
What enzyme is there a rise in in compartment syndrome?
creatine kinase
What body system is severely at risk in compartment syndrome?
renal; risk of renal failure (myoglobulinaemia)
What is the management for acute limb ischaemia?
- ECG
- bloods
- analgesia
- anticoagulate
- nil by mouth (patient should not drink or eat anything)
If the limb is salvageable, what should you suspect? (2)
- suspicion of embolus only; embolectomy
2. suspicion of thrombosis in situ
If the limb is not salvageable, what 2 options are available?
- Palliate patients (if patients doesn’t agree for amputation or if not advised)
- Amputation
What 2 procedures can be done if there is a suspicion of thrombosis in situ?
- endovascular; mechanical thrombectomy/ thrombolysis
2. open embolectomy +/- bypass
What is the mortality rate for amputations?
can be up to 20% (but depends on patient’s state)
What is embolectomy?
- emergency surgical procedure which involves removing embolus from vessel which leads to organ necrosis
- artery clamped, hole made in it and catheter inserted, balloon inflated beyond the clot and clot pulled out
What percentage of acute limb ischaemia is caused by embolus and thrombus?
- 30% embolus
- 60% thrombus in situ
When does irreversible muscle ischaemia occur in acute limb ischaemia patients?
in 6-8 hours following onset of symptoms
What is the mortality rate for acute limb ischaemia?
22% (due to necrosis)
What percentage of diabetics will develop a foot ulcer in their lifetime?
15%
Why is diabetic foot disease a big problem?
Because little option available for surgical intervention, therefore prevention is key (footcare, glycaemic control etc)
What is pathophysiology for diabetic foot disease? (4)
- microvascular peripheral artery disease
- peripheral neuropathy (lose sensation and pain sensation)
- mechanical imbalance
- susceptibility to infection (impaired immunity)
What aspects of footcare should be checked for patients at risk of diabetic foot disease?
- patient should always wear shoes
- check if fit footwear
- check pressure points/ plantar surface of foot regularly
- quick and regular woundcare on skin breaks
What is the best management for diabetic foot disease? (4)
- prevention
- good wound care
- tracking infection; consider systemic antibiotics
- investigate other disease risk: osteomyelitis (inflammation of bone), gas gangrene, cellulitis, lymphangitis and necrotising fasciitis (calcification in arteries common)
What surgical procedures can be considered for patients with a diabetic foot?
- revascularisation
2. amputation (as last available option but rate is high)
When should (endovascular or surgical) revascularisation be considered for diabetic foot disease?
- if disease if very distal; attempt distal crural angioplasty/stenting or distal bypass
