Background Information
Definitions
PAD is defined by the presence of atherosclerotic obstruction in the peripheral arteries of the lower limb
The clinical presentation of PAD can be categorised into 4 subsets: [Ref]
- Asymptomatic
- Chronic symptomatic PAD
- Chronic limb-threatening ischaemia (old term: critical limb ischaemia)
- Acute limb ischaemia: sudden (<2 weeks) decrease in limb perfusion that threatens limb viability (covered in a separate article)
Clinical Features
Patients with PAD often have concomitant cardiovascular risk factors:
- Smoking
- Diabetes
- Hyperlipidaemia
- History of coronary artery disease / cerebrovascular disease
There are 3 main clinical manifestations of chronic PAD: [Ref]
| Presentation | Symptoms | Signs |
|---|---|---|
| Asymptomatic | Note that these patients may self-limit and adapt their activity to remain below their ischemic threshold to avoid leg pain |
|
| Chronic symptomatic PAD | Most commonly presents as intermittent claudication (“angina of the legs”):
Location of pain:
|
|
| Chronic limb-threatening ischaemia (critical limb ischaemia – old term) | Characterised by the presence of
|
Characterised by the presence of tissue loss:
Other findings:
|
Key exam presentations:
- Pain with walking that is relieved by rest = intermittent claudication
- Pain at rest +/- ulcer or gangrene = chronic limb-threatening ischaemia (critical limb ischaemia)
Guidelines
Investigation and Diagnosis
Approach:
- 1st line: ABPIAnkle-brachial pressure index (in clinic)
- Then, perform imaging in secondary care if revascularisation is being considered
ABPI (Ankle Brachial Pressure Index)
How to measure:
- Similar to measuring a clinic BP – instead of using a stethoscope, a handheld doppler is used
- BP cuff placed on the arm and ankle
- Use doppler to locate the pulse (DPDorsalis pedis , PTPosterior tibial pulses & brachial pulses)
- Inflate the cuff until the pulse is no longer audible on doppler
- Deflate the cuff slowly and note the pressure (systolic BP) when doppler is audible again
ABPI calculation: highest ankle systolic BP (DPDorsalis pedis or PTPosterior tibial ) / highest brachial systolic BP (right or left arm)
Interpretation:
| ABPI | Interpretation |
|---|---|
| >1.4 | May suggest arterial calcification/stiffness (typically diabetesOther causes include systemic vasculitis, rheumatoid arthritis and advanced chronic renal failure.) Unable to rule in or out PAD |
| 1.0 – 1.4 | Normal |
| ≤0.9 | PAD |
| <0.5 | Chronic limb-threatening ischaemia |
Do not exclude a diagnosis of peripheral arterial disease in people with diabetes based on normal or raised ABPI alone.
- Diabetes can cause arterial calcification, which makes arteries more incompressible, thus a falsely high ABPI reading.
Alternative diagnostic test if ABPI is >1.4 (suggesting arterial calcification/stiffness) → toe-brachial index (TBI) [Ref]
- Same as ABPI but using digital artery
This is because the digital arteries in the toes are less likely to be noncompressible, even in patients with medial arterial calcification or diabetes, allowing for more accurate assessment of distal perfusion.
pulse in the toes.
Imaging
Imaging should be performed if revascularisation is being considered:
- 1st line: duplex ultrasound
- 2nd line: MR angiography with contrast
- 3rd line: CT angiography
Management
Definitive Management
Intermittent Claudication
| Step 1 | Supervised exercise programmeSupervised exercise 2 hours/week for 3 months. Encourage people to exercise to the point of maximal pain. |
| Step 2 | Revascularisation (see below for choosing approaches)
|
| Step 3 (if surgery is inappropriate for patient) | Naftidrofuryl oxalateVasodilator (5-HT2 receptor antagonist) |
NICE did not make any specific recommendations on choosing between endovascular vs open revascularisation approaches. Selected points from the 2024 ACC/AHA guidelines: [Ref]
- Endovascular revascularisation (angioplasty + stenting) is generally 1st line.
- Open revascularisation is preferred in:
- Multilevel occlusions
- Long-segment (>10cm) occlusions
- Lesions involving the common femoral artery and profunda femoris artery origin
Chronic Limb-Threatening Ischaemia (Critical Limb Ischaemia)
- Refer all patients to vascular specialist
- Offer revascularisation to all patients
- Recent trials suggest that open revascularisation is superior to endovascular in those with chronic limb-threatening ischaemia, especially if there is a suitable autogenous vein (e.g. great saphenous vein)
Secondary Prevention
Offer all the following:
- Lifestyle changes + treat comorbidities
- Atorvastatin 80 mg PO OD
- Clopidogrel 75 mg PO OD