Introduction

Peripheral vascular disease (PVD, also Peripheral Arterial Disease – PAD) is a chronic condition due to atherosclerosis of arteries in the limbs. The level of arterial occlusion present is proportional to the symptoms. The pathogenesis and risk factors are the same as for coronary artery disease (CAD), and include:
Classically peripheral vascular disease present as pain in the lower limbs which is brought on by exertion (typically the patient will be able to walk a specific distance before the pain comes on) and the pain is relieved by rest.
Peripheral Vascular Disease

Pathology of Peripheral Vascular Disease. This file is taken from wikimedia commons and is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

Epidemiology

  • Affects about 10-15% of the population
  • Usually CAD (coronary artery disease) is also present. About 75% of patients will have symptomatic CAD. In the other group of patients it is believed the CAD is masked by PVD, as the PVD prevents patients from exerting themselves to a degree which would initiate symptoms of CAD.

Presentation

The classical presentation involves:

  • Pain in the calves on walking, relieved by rest
    • This pain is also known as claudication
    • The pain can occur anywhere along the leg, and down into the foot
    • Many patients do NOT present with classic claudication – often because they are not doing enough activity to induce the symptoms – particularly if they have another comorbidity that limits their activity.
  • Pain may also occur when legs are raised (e.g. in bed), and abate when legs are lowered (e.g. by sitting)

The main differential is “spinal claudication” caused by impingement of the caudal equina by a spinal stenosis. This also classically causes pain in the back of the legs on exertion.

FUN FACT:

Claudication comes from the latin “to limp”, which itself derives from the Emperor Claudius – whom it was said walked with a limp

Examination

  • Elevating the leg may cause it to go pale and cold, as well as causing pain.
    • Beuger’s angle <20’ – the leg will go pale and cold upon raising it 20’ off the couch.
  • Increased vascular filling time – Upon lowering, the leg may become hot and red as reperfusion occurs. Perfusion time tends to be reduced (>15s)
  • Oedema is not usually present
  • There may be evidence of poor skin health due to poor perfusion, such as ulcers, dry scaly skin, cool peripheries and reduced capillary refill time
  • Check the pulse in the foot (posterior tibial and dorsals pedis)
    • Palpable pulses indicate reduced likelihood of peripheral vascular disease
    • Absent pulses represent an increased chance of peripheral vascular disease
    • If you are unable to locate a pulse by hand, you can use a doppler probe to assess if significant blood flow is present in the artery
    • For more information, see Peripheral Vascular Exam

    An example of a doppler probe used for assessing peripheral pulses

      An example of a doppler probe used for assessing peripheral pulses

Classification

Mild PVD

Claudication – this is limb pain (inc aching, cramping and tired feeling of the legs) upon exertion. It most commonly occurs in the calves, but may also be present in the feet, thighs, buttocks and even arms. The distance a patient can walk before they experience symptoms is known as the claudication distance.

  • Claudication could be thought of anginaof the limbs
  • Pain is usually relieved by rest
  • As claudication progresses, the distance that a patient can walk reduces.
Severe PVD

Can cause claudication / buttock pain at rest
Burning pain at night, due to elevation (which reduces limb perfusion), and is relieved by hanging the legs over the side of the bed (very bad sign!)
Patients may have:

  • ‘Punched out’ ischaemic ulcers – usually on the toes and heels, rarely higher up the limb. These tend to occur after a localised traumatic event. They are often painful, but diabetic and alcoholic patients may not notice.
  • Gangrene – often black necrotic gangrenous tissue surrounds the punched out ulcer lesions. Infection of this areas can occur (wet gangrene).
  • Reduced / absent peripheral pulses – start distally, and work your way up until you find the pulse
  • Skin atrophy – in chronic disease
  • Hair loss – in chronic disease
  • Cyanosis
  • Excessive sweating – due to overactivity of the sympathetic nerves
  • Erectile DysfunctionLeriche syndrome – the result of distal aortic disease. Other features of the syndrome are buttock pain, and pale, cold legs. Surgery may be useful to reduce symptoms in these patients
  • Amputation –may be necessary in patients with very severe disease. Usually only performed in patients with severe unremitting leg pain + gangrene, to prevent sepsis. Amputation should be performed as distally as possible, hopefully below the knee, as this provides the greatest flexibility with prosthetic replacement limbs, but must be high enough to provide sufficient perfusion to allow healing of the stump.  Thus above the knee amputation is likely to heal better.
    • Phantom limb pain is common, and usually treated with gabapentin. This is often used prophylactically, as this improves efficacy.

Investigations

The diagnosis can be made on the basis of a suggestive history and examination, in conjunction with an ABPI <0.9.

After diagnosis is made, typically a patient may be referred to the vascular team for further investigation, which would typically include a CT angiogram of the lower limb.

  • Arterial duplex ultrasound is an alternative to CT angio but is highly dependent on operator skill

ABPI – Ankle-Brachial pressure index

This is a measure of the ratio of the blood pressure in the ankle and the arm. As peripheral vascular disease affects the legs more than the arms, it can be used as an indicator of reduce arterial blood flow in the legs.

  • Measure the blood pressure in both arms and take the highest value
  • Measure the blood pressure in both ankles and take the highest value
    • Instead of the stethoscope, use a Doppler ultrasound probe to measure the pressure over the posterior tibial artery – record the pressure when your hear the first ‘whoosh’
  • Using only systolic values, divide the ankle pressure by the brachial pressure
  • A normal value is >1
  • A value of <0.9 is pathological for limb ischaemia (PVD). The lower the number, the greater the degree of PVD
  • Pain at rest – ABPI = <0.6
  • High Risk of gangrene – ABPI – <0.3, or ankle systolic pressure <55mmHg
  • CAUTION – in very severe arteriosclerosis the vessels are incompressible, and thus falsely high readings may be obtained (e.g. an ABPI >1.3)

Investigate for Diabetes

Bloods

  • Lipids
  • U+E’s
  • ESR/CRP – to exclude arteritis
  • ECGto check for cardiac involvement
  • Platelets and clotting

Arterial imaging

  • Should be performed to assess the extent of the disease
  • E.g. CT angiography (aka arteriography), DSA (digital subtraction arteriography), colour duplex imaging
  • Stop METFORMIN before arterial imaging – as it increases the risk of metabolic acidosis

Management

A diagnosis of peripheral vascular disease is confirmation that the patient has cardiovascular disease. Thus, as well as treating the peripheral vascular disease, many of the treatments are also aimed at reducing other complications of cardiovascular disease (such as stroke and MI).

The aim os PVD treatments are to improve the walking distance and lower limb circulation.

Medical management

All patients should be given:

  • Statin (e.g. atorvastatin 40mg nocte) regardless of cholesterol levels
  • All patients should be given an antihypertensive – as long as they are not hypotensive – for example an ACE-inhibitor (e.g. ramipril 5mg daily) or a calcium channel blocker (e.g. amlodipine 5mg daily)
    • β-blockers should be avoided, but are typically safe unless PAD is very severe
  • Antiplatelet agent – usually aspirin 100mg daily – can improve claudication distance and reduce other symptoms.

Lifestyle factors

  • Stop smoking
  • Lose weight
  • Increase exercise – e.g. 30-60 mins, 4x week – often undervalued as a treatment. May increase the claudication distance, and improve QoL. Thought to be beneficial by increasing collateral circulation, improved endothelial compliance (e.g. Better vasodilation), decreased blood viscosity.
    • 1/3 of patients will improve
    • 1/3/ will stay the same
    • 1/3/ will get worse
  • Symptom management
    • Raising the pillow 4-6 inches can help keep the legs below heart level and reduce leg pain at night
    • Avoid cold weather if possible
    • Foot care – inspection every day for lesions, with prompt treatment. Careful washing of the feet everyday with thorough drying

Control of risk factors

  • Screen for and treat diabetes if present

Surgical Interventions

Surgical treatments are typically reserved for patients with very severe symptoms or where tissue destruction is present.

Indications for specialist referral include:

  • Lifestyle limiting claudication
  • Pain at rest
  • Gangrene

Percutaneous Transluminal angioplasty – PTA – is useful for short lesions (usually <5cm) in big arteries. A balloon is used to widen the artery, which in some cases, may be enough on its own. In many cases, a stent is also placed. Particularly useful in iliac artery disease (successful in 75-90% of patients), and also successful in 50-70% of thigh and calf disease patients.

  • PTA is not good for long lesions. These are more likely to occur in diabetic patients.
  • Selection of patients is usually based on arterial imaging.
  • PTA can result in thrombus formation and subsequent embolisation
  • Reccurrence is about 30% at 3 years

Surgery – thromboendarterectomy and bypass grafting

  • Is suitable for some patients. These are usually those with an obvious blockage, where the distal vessel is still filled by collateral vessels (indicating that the distal vessel is still in good shape) – similar to the indications for PTA – however patients must be able to tolerate surgery. May be used in those in whom PTA was not successful.
  • These patients may receive a bypass graft. These are usually made from venous tissue, but prosthetic structures are also used.
    • Aspirin improves the longevity / patency of prosthetic grafts
    • Warfarin may be required after graft surgery in venous grafts
  • Sympathectomy may be used to relieve pain. This can be chemical or surgical, but as they are equally effective, and generally used in those who can’t tolerate other surgery, chemical sympathectomy is much more widely performed. Particularly useful in diabetic patients.

Other Interventions

Limb Compression

  • May help those with severe disease who are not candidates for surgery.
  • Inflatable cuffs are placed over the limb and inflated rhythmically for a period of 1-2 hours, several days per week
  • This is thought to improve both venous and arterial flow, thus reducing symptoms, but evidence is poor

References

  • Murtagh’s General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
  • Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.
  • Beers, MH., Porter RS., Jones, TV., Kaplan JL., Berkwits, M. The Merck Manual of Diagnosis and Therapy

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