- Aka peripheral arterial (occlusive) disease.
- Chronic PVD is due to atherosclerosis of peripheral arteries. Usually affects legs but can affect arms.
- Acute limb ischaemia results from total occlusion of an artery, due to progression of longstanding disease or an acute embolus (e.g. from AF). Tissue necrosis results within 6 hours if untreated.
- PVD is often synonymous with arterial occlusive disease. However, other types of peripheral vascular disease include: venous disease, aneurysmal disease, and carotid artery disease.
Locations of pain (and affected arteries):
- Upper ⅔ of calf (superficial femoral artery). Commonest site.
- Buttock and hip (aortic and iliac artery). 2nd commonest site.
- Thigh (iliac or common femoral artery).
- Lower ⅓ of calf (popliteal artery).
- Foot (tibial or peroneal artery).
- Claudication is a predictable, reproducible pain on exertion caused by ischaemia of the muscle, which is relieved by rest.
- 30% have classic intermittent claudication but most have a more atypical pattern, with some being asymptomatic. There may be a limp.
- Quantify severity by asking about how many yards they can walk before they have to stop because of the pain, on the flat, at a normal pace, on their best day.
Critical limb ischaemia
- Rest pain, unrelieved by medication for ≥2 weeks and/or evidence of tissue loss (ulcer or gangrene).
- In the context of neuropathy (e.g. co-morbid diabetes), pain may be absent.
- Pain is in the feet and toes, rather than calves. Worse at night due to reduced gravitational pull, so patient may sleep in a dependent position to try and maintain perfusion. This can result in a swollen leg, which may also be red from metabolite-triggered capillary dilation.
- Intermittent claudication. 2a if stop >200m, 2b if <200m.
- Rest or nocturnal pain.
- Pain at rest.
- Perishingly cold.
- Paralysis is a late feature suggesting irreversible damage.
Musculoskeletal e.g. osteoarthritis.
- Disc degeneration.
- Spinal stenosis.
- Alcoholic neuropathy.
Diagnose with ankle-brachial pressure index (ABPI):
- The ratio of systolic blood pressure at the ankle and arm, measured using doppler US.
- Procedure: take after 10 minutes at rest, and use the sides with the highest measurements.
- Results: roughly,
- ECG, lipids, glucose, BP.
- Combines usual grayscale US image with colour-doppler US to visualise flow.
- Helps determine site of disease.
Angiography if surgery considered:
- MR angio is a good choice when available.
- CT angio is better for showing wall abnormalities (e.g. aneurysm) and more available than MRA. Risks: contrast nephropathy, radiation.
- Intra-arterial digital subtraction angiogram (invasive): gold standard that also allows treatment. Risks: thrombus embolisation and/or vessel puncture, with 1/100 leading to limb loss.
- Advise patients to keep active. Can refer to exercise rehabilitation programme.
- Cardiovascular disease prevention. Clopidogrel is 1st line antiplatelet therapy in PVD.
- Foot care.
- The vasodilator naftidrofuryl can slightly increase walking distance.
- Indications: treatment-resistant disease, critical limb ischaemia, acute limb ischaemia.
- Options: surgical bypass, surgical endarterectomy, radiological angioplasty and stenting (easier with large vessels e.g. iliac). Bypass may involve grafting native vessel — e.g. saphenous vein for femoro-popliteal bypass — or synthetic vessel — e.g. for aorto-iliac or ilio-femoral bypass.
- Acute limb ischaemia: heparin IV then embolectomy with Fogarty catheter. Thrombolysis with alteplase if not surgically fit.
- Reperfusion injury may result from revascularisation, due to the systemic release of substances in the damaged tissue e.g. K+, myoglobin. Other complications include graft failure and limb loss.
- A last resort, considered in patients with ulceration and gangrene.
- Arterial ulcers.