Vascular Surgery Flashcards
What are the 6 Ps of acute limb ischaemia?
Pale Pulseless Pain Paralysis Parasthesia Perishingly cold
What is the best management for acute limb ischaemia?
Surgical intervention
How is ABPI calculated?
ABPI = the highest pressure in either the posterior tibial artery or dorsalis pedis artery in ONE foot divided by the highest pressure in the brachial artery from either arm
What is acute limb ischaemia?
A sudden decrease in limb perfusion that is a potential threat to viability of the limb
How common is acute limb ischaemia?
Affects 1 in 6000 people
What are the 2 main pathophysiologies of acute limb ischaemia?
- Acute thrombosis of a vessel with pre-existing atherosclerosis
- Emboli
Name some other rare causes of acute limb ischaemia?
- Aortic dissection
- Trauma
- Iatrogenic injury
- Peripheral aneurysm (esp. popliteal)
- Intra-arterial drug use
What proportion of acute limb ischaemia is caused by acute thrombosis of an already atherosclerosed vessel?
60%
What factors predispose a patient to acute thrombosis -> acute limb ischaemia?
Dehydration Hypotension Malignancy Polycythaemia Inherited pro-thrombotic states
How do the majority of emboli form?
Cardiac causes e.g. AF, MI, ventricular aneurysm
Where are the common sites of impaction of an embolus?
Brachial artery
Common femoral artery
Popliteal artery
Aortic bifurcation
When does irreversible tissue damage occur to a limb?
After 6 hours of severe ischaemia
How is acute limb ischaemia managed initially?
Emergency management - give 100% O2, IV access and consider crystalloids if dehydrated, blood tests, CXR and ECG. Opiate analgesia, refer upwards.
What blood tests do we request for acute limb ischaemia?
FBCs U+Es Troponin Clotting Glucose Group and save
How can you assess limb viability?
Look for pulses, temperature, appearance of skin, limb power, sensation, and cap refill
How does irreversible limb ischaemia appear?
Fixed mottling of skin, petechial haemorrhages, wood hard muscles
How does limb ischaemia appear if it is saveable but needs immediate treatment?
Muscles tender to palpation, swollen, loss of power and loss of sensation
How is irreversible limb damage managed definitively?
Amputation
How is severe limb ischaemia (requires immediate treatment) managed definitively?
Prevent systemic complications of muscle necrosis (acidosis, hyperkalaemia, AKI).
Surgery to revascularise the limb + perform fasciotomy
Consider amputation
How is severe limb ischaemia (requires prompt treatment after investigation) managed definitively?
Heparinisation
Angiogram/Duplex/CT to determine location of disease
Thrombolysis
Surgery
Which limb does chronic ischaemia occur in most commonly?
Lower limb
What are the causes of chronic limb ischaemia?
Atherosclerosis
Arteriosclerosis
How do we classify lower limb ischaemia?
The Fontaine classification
What are the 4 levels of Fontaine classification?
I - asymptomatic
II - intermittent claudication
III - Rest pain
IV - Ulcers/Gangrene
Which Fontaine classifications are critical limb ischaemia?
III and IV
What are the stats on intermittent claudication?
1/3 improve, 1/3 stable, 1/3 deteriorate
4% require intervention
What are the clinical features of IC?
Muscle pain on exercise (worse with increased intensity). Relieved by rest. Usually in calf muscle.
What are the differentials for IC?
- Spinal stenosis (usually while walking down stairs/hill, rather than up)
- OA (esp. of hip joint)
- Nerve root entrapment e.g. sciatica
How is IC diagnosed?
Clinical (not based on imaging)
Post exercise fall in ABPI
How is IC treated?
- Risk factor modification
- Pt should walk through pain -> angiogenesis -> establish collaterals
- Endovascular treatment
- Surgery
What are the risk factors for IC?
HTN Hyperlipidaemia DM Smoker FH
What is critical limb ischaemia?
Severe obstruction of the arteries which markedly reduces blood flow to the extremities which has progressed to severe rest pain +- ulcers.
How long must rest pain be present for to diagnose critical limb ischaemia?
2 weeks or more + no relief with simple analgesia
When is th pain usually worst with critical limb ischaemia?
At night i.e. when the pt is lying down
How is critical limb ischaemia diagnosed?
Clinically
How is critical limb ischaemia diagnosed?
- Identify risk factors to modify
- Identify vessels affected location and severity
How is criticla limb ischaemia treated?
REVASCULARISE as much as possible. Treat proximal disease before distal disease. Analgesia Angioplasty +- stent in proximal disease Surgery - bypass or amputation
What’s an aneurysm?
An abnormal localised blood vessel dilation by more than 50% of its original diameter
What is the definition of an AAA?
Dilation of the abdominal aorta greater than 3cm
What are the risk factors for AAA?
Smoking HTN Hyperlipidaemia FH Male Increasing age
What are the clinical features of AAA?
Mostly asymptomatic.
If not:
- Abdominal pain
- Back/loin pain
- Distal embolisation
- Aortoenteric fistula
What can be found O/E of a pt with AAA?
Pulsatile mass felt in the abdomen (above umbilical level)
How has the mortality rate of AAA decreased recently?
Screening programme!!
Who does the AAA screening programme screen?
Men in their 65th year
If a man is found to have an AAA on screening, what happens next?
If it is small (3.0-4.4cm) or medium (4.5-5.4cm), invite for ongoing US surveillance.
If large (>=5.5 cm) refer for surgical repair
How frequently should a small aneurysm be monitored?
Every 12 months
How frequently should a medium aneurysm be monitored?
Every 3 months
What are the differentials for AAA?
(If symptomatic) renal colic.
Other abdominal pathology
What happens after an USS confirms an AAA?
CT with contrast for anatomical details to determine if suitable for endovascular procedures
What can we modify for AAA and why?
Smoking cessation
BP control
Statin and aspirin therapy
Weight loss
Reduce risk of progression and mortality
Which AAA pts should be considered for surgery?
- AAA >5.5cm
- AAA expanding at >1cm/year
- Symptomatic AAA in otherwise fit pt
How can AAAs be repaired?
- Open repair
- Endovascular repair
Why do we offer surgery to pts with AAA over 5.5cms?
The risk of surgery becomes equal to risk of not having surgery at 5.5cm
Which procedure has better outcomes for AAA?
Endovascular has better short term outcomes, but worse long term. Open repair is reccommended in younger, fit pts as 2 year mortality is the same for both procedures.
What are the complications of AAA?
Rupture
Retroperitoneal leak
Embolisation
Aortoduodenal fistula
What factors are associated with an increased risk of AAA rupture?
Smoker, HTN (especially if uncontrolled), FHx, atherosclerosis
What is the rate of AAA rupture in pts with an AAA over 5.5cm?
3% per year
How many pts whose AAAs rupture reach hospital alive?
Less than 50%
What is the mortality rate for ruptured AAA?
75-95%
What are the symptoms of a ruptured AAA?
Severe epigastric &/or back/loin pain, collapse, Hx of AAA under surveillance
What are the signs of a ruptured AAA?
Sudden onset hypotension, pain, and sweating, pulsatile abdominal mass (often hard to feel due to pain causing pt to contract abdo wall muscles).
If a ruptured AAA is a distinct possibility, what should we not do in resus?
Chase a normal BP because that would risk worsening the rupture (unless pt is dangerously hypotensive, in which case call a peri-arrest cardiac emergency).
How is a ruptured AAA managed?
Surgically!
What are the possible complications of ruptured AAA surgical repair?
Death (that’s a biggy, like 50% of those operated on die), MI, renal failure, lower limb embolism, gut ischaemia, abdominal compartmet syndrome
What is carotid disease a risk factor for?
TIAs or CVAs
Who do we investigate for carotid disease?
Pts who have had a TIA or CVA in the past 6 months
How do we investigate carotid disease?
With a colour duplex scan. If this is inconclusive, MRA or CT angiography
What is a CEA and who is it offered to?
Carotid endarterectomy, offered to pts smptomatice with more than 70% stenosis of ICA, or more than 50% if recent TIA/CVA
What is the most common outcome of diabetic vascular complications?
Foot ulceration
What are the 4 key features of the diabetic foot?
Ulceration, sensory neuropathy, loss of ability to heal small injuries, and infection.
What are the risk factors for diabetic foot ulceration?
Previous ulceration, neuropathy, peripheral arterial disease, altered foot shape, callus, visual impairment, living alone, renal impairment
What % of diabetic foot ulceration is due purely to sensory neuropathy?
45%
What % of diabetic foot ulceration is due purely to ischaemia?
10%
What is the remaining 45% of diabetic ulceration due to?
Mixed neuropathic and ischaemic
How does a purely neuropathic ulcered foot present?
Warm foot with palpable pulses, evidence of sensory loss, normal or high ABPI
How does a mixed neuropathic/ischaemic ulcered foot present?
Cool, absent pulses, ulcers situated on toe, heel, or metatarsal head, ABPI may be high.
How do we manage diabetic ulcers (general steps)?
Prophylaxis, Surveillance, Treat infection, revascularise, amputate
What prophylactic steps can we take to prevent diabetic foot ulcers?
Diabetic nurse/clinic checkups regularly, appropriate footwear, chiropody, keep feet cool, don’t walk around barefoot
If there is infection present in a diabetic foot, what imaging should we do and why?
X-ray to look out for osteomyelitis
How do we attempt to revascularise a pt with diabetic foor tulcers?
Angioplasty, femorodistal bypass grafts