What is PVD
Peripheral arterial disease (PAD) is a major circulatory disorder characterised by arterial obstruction, leading to reduced blood supply and ischaemia in the lower limbs
Epidemiology of PVD
- M>F
- Prevalence increases with advancing age
- Commonly caused by atherosclerosis and usually affects the aorta-iliac and infra-inguinal arteries
RFs for PVD
- Diabetes mellitus
- Hypercholesterolaemia
- Hypertension
- Chronic kidney disease
- Age
- Male
- Smoking
What happens when muscle receives less oxygen?
becomes ischaemic, the cells release adenosine which affects nearby nerves, causing pain. Lactic acid production may also contribute to pain.
What are the 3 main patters of presentation?
intermittent claudication, critical limb ischaemia and acute limb-threatening ischaemia
What is intermittent claudication?
- inadequate increase in skeletal muscle perfusion during exercise
What is acute limb-threatening ischaemia
most commonly caused by emboli, usually of cardiac origin, resulting in a sudden decrease in limb perfusion. Emboli tend to lodge at artery bifurcations or in areas where vessels abruptly narrow.
Fontaine classification
I - Asymptomatic - low ABPI (<0.9)
II- Intermittent claudication - aching or burning in muscles of leg
IIa- after more than 200m of walking pain
IIb - less than 200m of walking relieved with minutes on rest for II
III - Critical limb ischaemia - rest pain - dangling leg over egde of bed for pain relief - risk of limb losss
IV - Tissue loss: Ulceration or gangrene
Sites of claudication implies sites of disease
- Common iliac:unilateral buttock
- Common femoral:unilateral thigh
- Superficial femoral:unilateral calf
- Aortoiliac (Leriche syndrome)may cause the triad of:
- Bilateral buttock and thigh claudication
- Absent or decreased femoral pulses
- Erectile dysfunction
Primary investigations
- Ankle-brachial pressure index (ABPI): record systolic blood pressure with an appropriately sized cuff in both arms and in the posterior tibial, dorsalis pedis, and, where possible, peroneal arteries
- Duplex ultrasound:first-line imaging, offering some information on the location and severity of stenosis.
- Assessment of cardiovascular risk factors: ECG, FBC, U&E, random glucose or HbA1c, serum cholesterol and lipid profiles
Management of intermittent claudication
- Exercise:
- Can be supervised or unsupervised exercise programme
- Management of cardiovascular risk factors: smoking cessation, HbA1c control, BP control, diet and weight management, lipid modification (statins), antiplatelet agents (e.g. clopidogrel)
Surgical intervention for intermittent claudication
- Referral to a vascular surgeon is required if quality of life does not improve after a 3-month course of supervised exercise therapy
- Endovascular procedurese.g. balloon dilatation (angioplasty), stents, and atherectomy
- Performed on lesions that are deemed to be haemodynamically significant and stenosis has a reasonable likelihood of limiting perfusion to the distal limb
- Bypass surgery: diverts blood around blocked artery
- Consideration of naftidrofuryl oxalate: vasodilator
What is critical limb ischaemia
Critical limb ischaemia is defined as rest or night pain for greater than 2 weeks, with or without tissue loss such as ulceration.
RFs for critical limb ischaemia
- Family history of vascular disease
- Smoking
- Sedentary lifestyle
- Age
- PVD
Signs of critical limb ischaemia
- Non-healing ulcer or wound with shiny, hairless skin
- Gangrene
- Absent or diminished pulses in the legs or feet
- Reactive hyperaemia:
Symptoms of critical limb ischaemia
- Pain: a history of ‘aching’ intermittent leg claudication for 2 or more weeks
- Restornight pain must be present
- Patients often hang their legs out of bed at night to relieve the pain
- Evidence of aortoiliac disease(Leriche syndrome)
- Cool peripheries
Primary investigations of critical limb ischaemia
- Ankle-brachial pressure index (ABPI):significant collateral vessels may form in chronic limb ischaemia, resulting in ABPI results that are more difficult to interpret
- >1.4= abnormally calcified vessels; false-negative often due to diabetes
- 0.9-1.2= normal; does not exclude the diagnosis if clinically suspected
- 0.5-0.9= claudication; mild to moderate arterial disease
- <0.5= rest pain, ulceration, gangrene (critical limb ischaemia)
- Duplex ultrasound:first-line imaging, offering information on the location and severity of stenosis
Conservative management of critical limb ischaemia - only 20% of patients
- Multidisciplinary team (MDT) referral: all patients should be referred to a vascular MDT unless inappropriate, such as palliative patients
- Analgesia: paracetamol with either a weak or strong opioid (depending on pain level)
- Supervised exercise programme:
Revascularisation for critical limb ischaemia - 65%
- Endovascular intervention:angioplasty or stenting is offered to 40% of patients and should be offered forshortocclusions
- Bypass surgery:offered to 25% of patients; preferred forlongocclusions
- Amputation:considered if revascularisation has been unsuccessful or is inappropriate
Complications of critical limb ischaemia
- Permanent limb weakness or pain:revascularise expediently to avoid this complication
- Acute-on-chronic limb ischaemia: patients with longstanding peripheral arterial disease may develop acute limb ischaemia
- Gangrene:occurs in the non-viable leg and usually requires amputation
What is acute limb ischaemia
sudden decrease in perfusion due to arterial occlusion, and can result in rapid ischaemia
RFs for acute limb ischaemia
Modifiable RFs - diabetes, smoking, HT, sedentary lifestyle
Non modifiable - FH of CA or PVD, Age older than 40
Most common form of ALI?
- Emboli followed by thrombosis
- Emboli causes - AF, MI, Valvular vegetation
- Most common site of emobolisation is femoral artery
What is first to be affected in ALI
Nerves are the first to be affected, with irreversible damage after 6 hours. Muscles are more tolerant, with irreversible damage after 6-10 hours, whilst the skin is the last to show necrosis.
