Peripheral vascular disease

Description

Atherosclerotic occlusive disease of non-coronary, non-cerebral arteries - in practice, the lower limbs
A marker of systemic atherosclerosis: the limb is the presentation, the heart is the risk

Spectrum

Stage	Presentation
Asymptomatic	~50% - detected only by ABI
Intermittent claudication	Reproducible calf/thigh/buttock pain on walking, relieved by rest within minutes
Chronic limb-threatening ischaemia (CLTI)	Rest pain >2 weeks, ulceration or gangrene
Acute limb ischaemia	Sudden - the 6 Ps. A surgical emergency

Fontaine I-IV / Rutherford 0-6
Leriche syndrome - aortoiliac disease: buttock/thigh claudication + impotence + absent femoral pulses
Level of pain localises the lesion one level above: buttock -> aortoiliac, thigh -> common femoral, calf -> superficial femoral (commonest), foot -> tibial/peroneal

~10-15% of those over 60; ~20% over 70
M>F, though the gap narrows with age
Smoking is the strongest risk factor for PAD specifically - relative risk 2-6x, stronger than for coronary disease
Diabetes: 2-4x risk, and shifts disease distally (tibial/peroneal), making revascularisation harder
High burden in Aboriginal and Torres Strait Islander communities - amputation rates several-fold higher

Atherosclerosis in >90%
Risk factors: smoking, diabetes, hypertension, dyslipidaemia, CKD, age, hyperhomocysteinaemia
Progressive stenosis -> flow limitation on exertion -> claudication; collateral formation preserves rest perfusion until stenosis is critical
Rest pain implies perfusion inadequate for basal metabolic demand - typically ankle pressure <50 mmHg
Non-atherosclerotic causes - consider in the young or in the absence of risk factors
- Thromboangiitis obliterans (Buerger disease) - heavy smokers <45, distal vessels, upper and lower limb, migratory thrombophlebitis
- Popliteal artery entrapment and cystic adventitial disease - young, athletic, normal pulses at rest
- Fibromuscular dysplasia, vasculitis (Takayasu, GCA), radiation arteritis, ergot
- Embolic (AF, aneurysm, endocarditis), thrombosis in situ

Clinical signs of peripheral arterial disease

Diminished or absent distal pulses
Femoral systolic bruits
Pallor and coolness of the affected limb
Hair loss, shiny atrophic skin, thickened nails
Delayed capillary refill
Positive Buerger test - pallor on leg elevation, delayed rubor (reactive hyperaemia) on dependency
Muscle wasting; ulcers: punched-out, painful, on pressure points/toes/heel (contrast venous ulcers - gaiter area, shallow, exudative, less painful)

Ankle-brachial index - the bedside test

ABI	Interpretation
>1.4	Incompressible - calcified vessels (diabetes, CKD). Uninterpretable; use toe-brachial index (<0.7 abnormal)
0.9-1.4	Normal
0.5-0.9	PAD - claudication range
<0.5	Severe; <0.4 or ankle pressure <50 mmHg -> critical ischaemia

Exercise ABI if symptoms are typical but resting ABI is normal - a fall of >20% confirms

Imaging - only when revascularisation is contemplated

Assess the whole patient

Screen for coexisting coronary and carotid disease - PAD is a coronary risk equivalent
HbA1c, lipids, UEC/eGFR, FBE
Screen for AAA with ultrasound in men over 65 who smoke

The limb symptom is the reason they came; the cardiovascular risk is what will kill them. Treat both, but never omit the second.

A. Cardiovascular risk reduction - highest priority, every patient

Smoking cessation - the single most effective intervention; nicotine replacement, varenicline, behavioural support
High-intensity statin regardless of baseline lipids - target LDL <1.4 mmol/L (<1.8 minimum)
- Add ezetimibe then a PCSK9 inhibitor if not at target
Antiplatelet: clopidogrel 75 mg is preferred over aspirin in PAD (CAPRIE)
Low-dose rivaroxaban 2.5 mg bd + aspirin reduces major adverse limb and cardiac events in symptomatic PAD (COMPASS/VOYAGER PAD) - at the cost of bleeding; select carefully
BP target <130/80; ACE inhibitor has benefit beyond BP lowering
Diabetes: HbA1c target individualised; SGLT2 inhibitors and GLP-1 RAs preferred (note early amputation signal with canagliflozin, largely not replicated)

B. Claudication

Supervised exercise therapy is first-line and outperforms both drugs and endovascular therapy for walking distance
- 30-45 min, 3x/week, for >=12 weeks, walking to near-maximal claudication pain
- Under-referred, and the most common omission in exam answers
Structured home-based programmes where supervised is unavailable
Revascularisation only for lifestyle-limiting claudication that has failed exercise and risk factor therapy
- Endovascular (angioplasty +/- stent) for short focal aortoiliac/femoropopliteal lesions
- Surgical bypass for long occlusions or failed endovascular
Cilostazol is not marketed in Australia; pentoxifylline is ineffective

C. Chronic limb-threatening ischaemia

Urgent vascular referral - revascularisation within days, not weeks
Analgesia (often opioid), wound care, offloading, treat infection
Multidisciplinary high-risk foot service - podiatry, vascular, endocrine, infectious diseases
Primary amputation if the limb is unsalvageable or the patient non-ambulant

D. Acute limb ischaemia - emergency

The 6 Ps: Pain, Pallor, Pulselessness, Paraesthesia, Paralysis, Perishing cold
Immediate IV heparin, analgesia, urgent vascular surgical referral
Paralysis or fixed mottling -> irreversible; hours matter
Embolectomy, thrombolysis or bypass; anticipate reperfusion injury and compartment syndrome; look for the source (AF, aneurysm)

E. Foot care - all patients with diabetes and PAD

Coronary artery disease (~50-60% have significant CAD) and cerebrovascular disease
Abdominal aortic aneurysm
Diabetes and diabetic neuropathy - neuroischaemic foot ulceration
CKD - accelerates and calcifies
Smoking, COPD, lung cancer
Erectile dysfunction (shares the mechanism and often precedes)
Depression and reduced functional capacity

The limb does better than the patient

Claudication is stable in ~70-80% at 5 years; ~10-20% worsen, only ~1-2% per year progress to critical ischaemia or amputation
Chronic limb-threatening ischaemia: ~25% dead and ~25% amputated at 1 year

Mortality

All-cause mortality ~30% at 5 years, ~50% at 10 years - mostly myocardial infarction and stroke
Mortality tracks ABI: the lower the index, the higher the cardiovascular death rate, independent of symptoms
A patient with asymptomatic PAD on ABI has the same cardiovascular risk as one with established coronary disease - treat accordingly

Monitor

6 more sections, plus exam facts

Premium unlocks every note across every specialty, and the full exam fact library behind it.