Peripheral Arterial Disease

Question 1

what is PAD?

Answer 1

a term used to describe a narrowing or occlusion of peripheral arteries which affects the blood supply to the lower limbs

Question 2

most common cause of PAD

Answer 2

atherosclerosis

Question 3

non modifiable risk factors for PAD (3)

Answer 3

sex (male), age, family history (PAD or other cardiovascular disease)

Question 4

modifiable risk factors for PAD (6)

Answer 4

Smoking; diabetes; hypertension; hypercholesterolemia; hyperhomocysteinemia; CRP levels

Question 5

Fontaine classification of PAD (chronic)

Answer 5

I - asymptomatic
IIa - Mild claudication
IIb - moderate/severe claudication (can only walk short distances)
III - ischaemic rest pain
IV - ulceration/gangrene

Question 6

rutherford classification (acute limb ischaemia)

Answer 6

I - Viable
IIa - marginally threatened
IIb - immediately threatened
III - irreversible

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4232437/

Question 7

most common symptom of PAD?

Answer 7

intermittent claudication

Question 8

what is intermittent claudication and where does it commonly occur?

Answer 8

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)

Question 9

what blood vessels are blocked during lower limb intermittent claudication

Answer 9

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

Question 10

vascular differential diagnosis for PAD (6)

Answer 10

aneurysm; limb trauma; radiation exposure; vasculitis; ergot use (migraines); popliteal entrapment syndrome; chronic venous disease

Question 11

neuro differential diagnosis for PAD (4)

Answer 11

neurospinal - disc disease, spinal stenosis, tumour; neuropathic - alcohol abuse

Question 12

MSK differential diagnosis for PAD (5)

Answer 12

pain from bones, joints, ligaments, tendons, fasical elements

Question 13

leriche syndrome triad

Answer 13

claudication; absent femoral pulses; erectile dysfunciton

Question 14

characteristics of chronic limb threatening ischaemia (3)

Answer 14

ischaemic rest pain; ischaemic ulcer; gangrene (wet or dry)

Question 15

why does ischaemic rest pain occur?

Answer 15

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)

Question 16

where do ischaemic ulcers usually form?

Answer 16

sites of increased focal pressure e.g. malleoli, tips of toes, heels etc.; usually dry and punctate

Question 17

what is dry gangrene, how does it occur, management?

Answer 17

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

Question 18

what is wet gangrene, how does it occur, management?

Answer 18

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

Question 19

what to look for in a clinical exam

Answer 19

inspection (scars from previous vascular surgery etc., gangrene, venous guttering); buerger’s test; pulses palpation; asculation for bruits; ABPI measurement

Question 20

vascular investigation for PAD (4)

Answer 20

duplex scan (hard if femoral pulses affected); CT angiography; MRI angiography; contrast angiography

Question 21

management for mild claudication

Answer 21

lifestyle: stop smoking, exercise, diet control;
Pharma: risk factor modification (control BP, cholesterol etc.), antiplatelet therapy

Question 22

role of statins

Answer 22

reduce cholesterol levels and helps to reduce plaque build-up by decreasing ‘stickiness’ of bvs

Question 23

short distance claudication management

Answer 23

lifestyle: supervised exercise class;
pharma: BP/DM/cholesterol control, antiplatelets/statins, naftidrofuryl/cilostazol (last resort)

invasive therapies can be some if severe

Question 24

surgical/endovascular interventions (what they are, when used, complications - 3)

Answer 24

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.

Question 25

common amputation sites (5)

Answer 25

toe; ray (toe through metatarsal bone); trans-metatarsal (all the toes through met bones); below knee; above knee

Question 26

amputations complications (7)

Answer 26

failure of wound to heal; flap necrosis; wound infection; post-amputation pain; stump haematoma; flexion contractures; psychological problems

Question 27

when should post-amputation rehab start and why?

Answer 27

ASAP - prevents flexion contractures

Question 28

prognosis of critical limb ischaemia

Answer 28

high risk of amputation and death (50% five year all-cause mortality)

Question 29

what is acute limb ischaemia

Answer 29

a sudden decrease in limb perfusion that causes a threat to limb viability (if presenting within 2 weeks of event)

Question 30

embolic source of acute limb ischaemia (8)

Answer 30

cardiac - AF, MI, endocarditis, valvular disease, atrial myxoma, prosthetic valves
arterial - aneurysm, atherosclerotic plaque

Question 31

thrombotic source of acute limb ischaemia (6)

Answer 31

vascular grafts; atherosclerosis; thrombosis of aneurysm; entrapment syndrome; hypercoagulable state; low flow state

Question 32

traumatic source of acute limb ischaemia (3)

Answer 32

blunt; penetrating; iatrogenic

Question 33

symptoms of acute limb ischaemia (6)

Answer 33

pain; pulselessness; pallor; poikilothermia (perishingly cold); paraesthesia; paralysis

Question 34

when should you not attempt to revascularise and acutely ischaemic limb and why

Answer 34

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

Question 35

initial investigation for acute limb ischaemia (5)

Answer 35

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)

Question 36

management of acute limb ichaemia

Answer 36

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

Question 37

differential for acute limb ischaemia (3)

Answer 37

Compartment syndrome; PAD; Critical limb ischemia

Question 38

acute limb ischaemia mortality rate

Answer 38

15-20% - a third of these coming from metabolic complications such as acidosis and hyperkalemia