Contents
Introduction
- Hypertension
- Dyslipidaemia
- High LDL and low LDL levels
- Diabetes
- Obesity
- FHx of arterial disease
- Significant if a first degree relative had MI before the age of 55
- Smoking
- Age
- Male gender
Epidemiology
- Affects about 10-15% of the population
- Usually CAD (coronary artery disease) is also present. About 75% of patients will also 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 low 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
Classification
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 as ‘angina’ of the limbs
- Pain is usually relieved by rest
- As peripheral vascular disease progresses, the distance that a patient can walk reduces.
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 poor prognostic 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 have pain.
- 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 Dysfunction – Leriche 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, ideally 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. In many cases, 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 vs the arm. As peripheral vascular disease affects the legs more than the arms, it can be used as an indicator of reduced arterial blood flow in the legs.
With the patient lying flat on the couch:
- 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
- HbA1c
- Lipids
- U+E’s
- ESR/CRP – to exclude arteritis
- ECG – to 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
Differentials
The most likely differential diagnosis is a neurological cause – typically compression of the spinal cord due to spinal stenosis – sometimes referred to as neurogenic claudication. This can cause a similar pattern of pain on activity in the buttocks, radiating down the legs, alleviated by rest.
- PVD – pain starts in calf and typically radiates up the leg
- Neurogenic claudication – pain typically starts in the buttock and radiates down the leg
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 aimed at reducing other complications of cardiovascular disease (such as stroke and MI).
The aim of PVD treatment is to improve the walking distance and lower limb circulation.
- There are no medications that are proven to improve the symptoms of intermittent claudication
- Walking therapies – can be as effective as surgery at improving symptoms
Medical management
All patients should be given:
- Statin (e.g. atorvastatin 40mg nocte) regardless of cholesterol levels
- Control hypertension – 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 – aspirin 100mg daily or clopidogrel 75mg daily – can improve claudication distance and reduce other symptoms.
Lifestyle factors
- Stop smoking
- Lose weight – aim for BMI 18.5 – 24.9
- Increase exercise – e.g. 30-60 mins, 5x 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 (i.e. better vasodilation to overcome the lumen narrowing and improve blood flow), decreased blood viscosity.
- May be as effective as surgery
- Explain to patients to walk until limits by claudication, rest until symptoms resolve, and then try again
- If patients find stopping in the street frequently embarrassing – try recommending they do their exercises at a shopping mall – where frequent stopping is more socially acceptable!
- 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 – encourage self inspection daily 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
- Patients with known cardiovascular disease are automatically considered high risk for diabetes
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
Flashcard
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
- Peripheral Vascular Disease – Health Pathways