Peripheral Arterial Disease Flashcards
what is PAD?
a term used to describe a narrowing or occlusion of peripheral arteries which affects the blood supply to the lower limbs
most common cause of PAD
atherosclerosis
non modifiable risk factors for PAD (3)
sex (male), age, family history (PAD or other cardiovascular disease)
modifiable risk factors for PAD (6)
Smoking; diabetes; hypertension; hypercholesterolemia; hyperhomocysteinemia; CRP levels
Fontaine classification of PAD (chronic)
I - asymptomatic
IIa - Mild claudication
IIb - moderate/severe claudication (can only walk short distances)
III - ischaemic rest pain
IV - ulceration/gangrene
rutherford classification (acute limb ischaemia)
I - Viable
IIa - marginally threatened
IIb - immediately threatened
III - irreversible
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4232437/
most common symptom of PAD?
intermittent claudication
what is intermittent claudication and where does it commonly occur?
exercise-induced muscle pain that it worse when walking uphill/hurrying and relieved by rest; most commonly occurs in the calf (bending knees restricts blood flow), thighs or buttocks (bifurcation of aorta)
what blood vessels are blocked during lower limb intermittent claudication
hip/buttock - aortoiliac;
thigh - aortoiliac or common femoral;
upper 2/3 of the calf - superficial femoral;
lower 1/3 of the calf - popliteal artery;
foot - tibial or peroneal artery
vascular differential diagnosis for PAD (6)
aneurysm; limb trauma; radiation exposure; vasculitis; ergot use (migraines); popliteal entrapment syndrome; chronic venous disease
neuro differential diagnosis for PAD (4)
neurospinal - disc disease, spinal stenosis, tumour; neuropathic - alcohol abuse
MSK differential diagnosis for PAD (5)
pain from bones, joints, ligaments, tendons, fasical elements
leriche syndrome triad
claudication; absent femoral pulses; erectile dysfunciton
characteristics of chronic limb threatening ischaemia (3)
ischaemic rest pain; ischaemic ulcer; gangrene (wet or dry)
why does ischaemic rest pain occur?
sue to inadequate oxygen perfusion at rest - when lying down blood cannot reach the feet/lower limbs bc there is no gravity to aid (BP in limbs too low to push blood through)
where do ischaemic ulcers usually form?
sites of increased focal pressure e.g. malleoli, tips of toes, heels etc.; usually dry and punctate
what is dry gangrene, how does it occur, management?
when the tissue dries up and turns blue/black due to reduced blood flow; common in people with diabetes and infection is not present; left to auto-amputate
what is wet gangrene, how does it occur, management?
liquefactive necrosis of tissue due to infection (‘wet’ bc pus), infection can spread through the body so can be fatal; occurs when dry gangrene becomes infected; give IV Abx (high dose), revascularise, debride, amputate if necessary
what to look for in a clinical exam
inspection (scars from previous vascular surgery etc., gangrene, venous guttering); buerger’s test; pulses palpation; asculation for bruits; ABPI measurement
vascular investigation for PAD (4)
duplex scan (hard if femoral pulses affected); CT angiography; MRI angiography; contrast angiography
management for mild claudication
lifestyle: stop smoking, exercise, diet control;
Pharma: risk factor modification (control BP, cholesterol etc.), antiplatelet therapy
role of statins
reduce cholesterol levels and helps to reduce plaque build-up by decreasing ‘stickiness’ of bvs
short distance claudication management
lifestyle: supervised exercise class;
pharma: BP/DM/cholesterol control, antiplatelets/statins, naftidrofuryl/cilostazol (last resort)
invasive therapies can be some if severe
surgical/endovascular interventions (what they are, when used, complications - 3)
angioplasty (+ stent): fractures arterial plaque and remodels artery, effective for short focal stenoses without heavy clacification, complications incl. arterial puncture site haemorrhage, dissection, emoblisation etc.
endarectomy: removes build up of plaques, for readily accessible sites e.g. femoral artery, complication incl. bleeding, infection, limb loss, DVT etc.;
bypass: bypasses the blockage and may use an autologous vein or prosthetic graft, used for long stretched of occlusion, complication incl. bleeding, infection, rejection of graft, DVT etc.
common amputation sites (5)
toe; ray (toe through metatarsal bone); trans-metatarsal (all the toes through met bones); below knee; above knee
amputations complications (7)
failure of wound to heal; flap necrosis; wound infection; post-amputation pain; stump haematoma; flexion contractures; psychological problems
when should post-amputation rehab start and why?
ASAP - prevents flexion contractures
prognosis of critical limb ischaemia
high risk of amputation and death (50% five year all-cause mortality)
what is acute limb ischaemia
a sudden decrease in limb perfusion that causes a threat to limb viability (if presenting within 2 weeks of event)
embolic source of acute limb ischaemia (8)
cardiac - AF, MI, endocarditis, valvular disease, atrial myxoma, prosthetic valves
arterial - aneurysm, atherosclerotic plaque
thrombotic source of acute limb ischaemia (6)
vascular grafts; atherosclerosis; thrombosis of aneurysm; entrapment syndrome; hypercoagulable state; low flow state
traumatic source of acute limb ischaemia (3)
blunt; penetrating; iatrogenic
symptoms of acute limb ischaemia (6)
pain; pulselessness; pallor; poikilothermia (perishingly cold); paraesthesia; paralysis
when should you not attempt to revascularise and acutely ischaemic limb and why
when the limb is no longer viable (paralysis, paresthesia); due to reperfusion injuries e.g. toxins built up during anaerobic resp being transported across the body
initial investigation for acute limb ischaemia (5)
CT angiography - can help determine if the cause is thrombotic or embolic and allows a more definitive management plan to be drawn up; ABCDE; Blood tests (FBC, U&Es, LFTs, Clotting profile); Serum lactate (assess severity of ischaemia); duplex/doppler scan (confirm absence of pulses)
management of acute limb ichaemia
immediately referred to vascular surgeons - this is an emergency! IV heparin will be given post diagnosis;
Further management then depends the kind of occlusion: thrombotic - percutaneous catheter-directed thrombolysis, surgical thrombectomy, percutaneous mechanical thrombus extraction or bypass surgery; embolic - embolectomy, percutaneous catheter-directed thrombolysis, bypass surgery
differential for acute limb ischaemia (3)
Compartment syndrome; PAD; Critical limb ischemia
acute limb ischaemia mortality rate
15-20% - a third of these coming from metabolic complications such as acidosis and hyperkalemia
