Definitions
Lower limb peripheral arterial disease (PAD) may present symptomatically either with pain on exercise (intermittent claudication) or with signs/symptoms at rest (previously “critical limb ischaemia” – this term has now been replaced by “chronic limb threatening ischaemia” (CLTI)).
Patients with CLTI typically have pain in the most distal part of the limb (toes) that is worse when the leg is elevated (e.g. at night), then relieved by hanging the leg down/sleep in a chair and/or a wound or lesion (tissue loss), usually below the ankle, that is painful or non-healing.
Patients with tissue loss who have diabetes and reduced perfusion often present without pain.
The pathway for people with diabetes and a new active foot problem is on REMEDY:
Diabetes Foot Care (Remedy BNSSG ICB)
Intermittent Claudication
This is the most common way in which people present with symptomatic PAD. Pain is felt in the large muscle groups when demand for oxygen increases during exertion and the delivery of oxygen (due to PAD) cannot keep up (anaerobic metabolism and lactic acid build up). Pain in the calf, thigh or buttock will occur usually after a predictable distance, be worse on hills and will disappear after a reproducible period of rest.
Cramping in these muscle groups at night is common and is not a sign of CLTI.
Intermittent claudication has a benign prognosis relating to the limb.
Very few go on to develop CLTI and less than 1/100 patients who present initially with claudication will progress to major lower limb amputation.
However, a diagnosis of symptomatic peripheral arterial disease is associated with a higher risk of heart attack or stroke (2-6x fold increase) and cardiovascular death. The management of the patient’s cardiovascular risk is the priority.
History and Examination
Assessment of the patient presenting with leg pain on exertion should include direct questioning and examination for potential red flag symptoms/signs that may warrant urgent referral to secondary care (see below).
The presence or absence of a peripheral pulses is not objective and does not rule out PAD.
Investigations
Ankle brachial pressure index (ABPI) measurements at rest can be useful. The normal range for ABPI is 0.9-1.3.
An ABPI < 0.9 confirms the diagnosis PAD. However, a normal ABPI does not fully exclude the diagnosis.
An ABPI of >1.3 may be due to arterial calcification (PAD) but is most commonly simply due to swelling in the limb falsely elevating the pressure needed to compress the artery. Patients who have ABPI >1.3 can have toe pressure assessment by Vascular Studies as this is less likely to be affected by swelling or calcification.
Toe pressure brachial index (TBPI) of >0.7 usually excludes PAD, whilst a TBPI <0.7 is suggestive of PAD. This test can be performed by community teams or Vascular studies at BRI, Weston or NBT by ICE request directly from primary care (see below)
Asymptomatic patients with low or high/incompressible ABPI do not need referral to a specialist.
The most accurate way of making the diagnosis of intermittent claudication is an exercise ABPI conducted by Vascular Studies. This can be requested directly from primary care (via ICE – see referral section below). This involves measuring the ABPI at rest then performing a standardised treadmill test or tip toe exercise then reassessing the ABPI. If the ABPI drops by more than 20% after exercise the test confirms the diagnosis of symptomatic PAD.
Most patients with intermittent claudication can be managed in primary care (see management section below)
Referral of patients with intermittent claudication should be considered when:
Patients referred without red flag symptoms who do not already have a confirmed diagnosis of symptomatic arterial disease will be triaged “straight to test” (exercise ABPI).
Secondary Care Management - what to expect
The majority of patients who have a positive exercise test or with previously proven symptomatic/treated PAD will see a member of the specialist vascular nursing team. We will
Most patients will be discharged back to primary care after review. A small proportion of patients with severely lifestyle limiting claudication will go on to have arterial imaging (duplex ultrasound) and follow-up. Intervention is unusual.
Vasodilator therapy
Naftidrofuryl Oxalate can be used in patients who do not improve with exercise (Naftidrofuryl oxalate | Prescribing information | Peripheral arterial disease | CKS | NICE) however it is not widely used in current vascular practice.
If referral is not indicated then the management of the patient with intermittent claudication is usually safely done in primary care. The key aspects of management are:
Perform ABPI in the practice or referral to Vascular Studies for gold standard test– see referral section below.
See also the BNSSG Formulary Cardiovascular System Guidelines
There is no standardised agreed exercise programme for patients with intermittent claudication. However, a patient information leaflet in available from the NHS on lifestyle changes including exercise:
Most studies have demonstrated that supervised exercise classes achieve better results than unsupervised exercise, and that 30 minutes, at least 3 times per week is optimal. Furthermore, patients need to exercise up to the point of discomfort to gain benefit; however, it is usually unhelpful to suggest that patients should “walk through the pain”.
The vascular team recommend that patients are encouraged to exercise for half an hour, three times a week in the form of a “training programme” (going for a walk with the purpose of trying to improve walking, rather than simply walking to the shops etc). They should exercise up to the point of discomfort, then rest until the pain subsides, then exercise again, repeating for the half an hour period.
Most initial benefit from exercise is derived from adaptation in the muscle (training effect – more efficient muscle able to do more with less oxygen need) rather than development of “new blood vessels”.
The availability/capacity of supervised exercise classes in BNSSG is limited. A programme is run through Physiotherapy at Bristol Royal Infirmary with exercise class once per week for 12 weeks. This is not available directly from a GP referral and access to this service remains via referral from vascular surgery.
Modern vascular practice has moved away from invasive treatment for claudication (e.g. angioplasty/stenting or surgery) as this is associated with worse long-term outcomes, with high rates of re-intervention and higher rate of major amputation than exercise. Patients referred to vascular surgery for assessment and management advice should not be given the expectation that intervention will follow.
Patients who present with the following symptoms should be referred urgently to the vascular surgery triage service via eRS.
Symptoms suggestive of CLTI
The pain is usually felt in the toes (further distance from the heart) and is made better by dangling the limb out of bed, or most commonly sleeping in the chair. The pain is often described as relentless, unbearable or burning. Feeling of numbness (in non-diabetic patients) at night may precede ischaemic rest pain but it is not a reliable indicator of reduced perfusion.
Signs suggestive of CLTI
The presence or absence of a foot pulse is not necessarily relevant. We would expect a present with CLTI to have an ABI<0.4 or absolute pressure at the ankle of <50mmHg. A patient with low ABI/toe pressure with no symptoms/signs does not have CLTI.
People with tissue loss in the foot who have associated signs or systemic symptoms of infection should be referred as as an emergency (see below).
If Acute Limb Ischaemia is suspected then arrange emergency admission (see below). Features include:
Emergency referrals can be made to the vascular network in 2 ways
Vascular studies can be requested directly in the following ways:
All vascular referrals should be sent via eRS to the Vascular Surgery Triage Service (RAS). Referrals will be triaged on a daily basis by the vascular team and booked into appropriate clinics. Please include all relevant clinical and contact details in referrals to help facilitate the triage process.
This is also the way to access the Vascular Hot Clinic at Southmead Hospital for patients requiring urgent review but not necessarily admission.
NICE CKS - Diagnosis of Peripheral Arterial Disease on management of PAD
Patient information: Lifestyle and Medical Management of PAD - Circulation Foundation
Patient information: Exercise for Intermittent Claudication - Circulation Foundation
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