Peripheral Arterial Disease Flashcards
Peripheral arterial disease (PAD) refers to the ?
narrowing of the arteries supplying the limbs and periphery, reducing the blood supply to these areas. It usually refers to the lower limbs, resulting in symptoms of claudication.
Intermittent claudication is ?
a symptom of ischaemia in a limb, occurring during exertion and relieved by rest. It is typically a crampy, achy pain in the calf, thigh or buttock muscles associated with muscle fatigue when walking beyond a certain intensity.
Critical limb ischaemia is the?
end-stage of peripheral arterial disease, where there is an inadequate supply of blood to a limb to allow it to function normally at rest. The features are pain at rest, non-healing ulcers and gangrene. There is a significant risk of losing the limb.
Acute limb ischaemia refers to?
a rapid onset of ischaemia in a limb. Typically, this is due to a thrombus (clot) blocking the arterial supply of a distal limb, similar to a thrombus blocking a coronary artery in myocardial infarction.
Gangrene refers to?
death of the tissue, specifically due to an inadequate blood supply.
TOM TIP: Think about risk factors when taking a history from someone with suspected atherosclerotic disease (such as someone presenting with intermittent claudication). Ask about their exercise, diet, past medical history, family history, occupation, smoking, alcohol intake and medications. This will help you perform well in exams and when presenting to seniors.
Medical co-morbidities increase the risk of atherosclerosis and should be carefully managed to minimise the risk:
Diabetes
Hypertension
Chronic kidney disease
Inflammatory conditions such as rheumatoid arthritis
Atypical antipsychotic medications
Peripheral arterial disease presents with?
intermittent claudication.
Patients describe a crampy pain that predictably occurs after walking a certain distance. After stopping and resting, the pain will disappear. The most common location is the calf muscles, but it can also affect the thighs and buttocks.
The features of critical limb ischaemia can be remembered with the “6 P’s” mnemonic:
Pain
Pallor
Pulseless
Paralysis
Paraesthesia (abnormal sensation or “pins and needles”)
Perishing cold
Critical limb ischaemia typically causes?
burning pain. It is worse at night when the leg is raised, as gravity no longer helps pull blood into the foot.
Leriche Syndrome
Leriche syndrome occurs with occlusion in the distal aorta or proximal common iliac artery. There is a clinical triad of:
Thigh/buttock claudication
Absent femoral pulses
Male impotence
Signs on examination which indicate risk factors for PAD?
Tar staining on the fingers
Xanthomata (yellow cholesterol deposits on the skin)
Examination signs of cardiovascular disease:
Missing limbs or digits after previous amputations
Midline sternotomy scar (previous CABG)
A scar on the inner calf for saphenous vein harvesting (previous CABG)
Focal weakness suggestive of a previous stroke
On examination, the peripheral pulses may be weak on palpation:
Radial
Brachial
Carotid
Abdominal aorta
Femoral
Popliteal
Posterior tibial
Dorsalis pedis
What can you use to accurately assess the pulases when the peripheral pulses are difficult to palpate?
a hand-held doppler
Signs of arterial disease on inspection are:
Skin pallor
Cyanosis
Dependent rubor (a deep red colour when the limb is lower than the rest of the body)
Muscle wasting
Hair loss
Ulcers
Poor wound healing
Gangrene (breakdown of skin and a dark red/black change in colouration)
On examination, there may be:
Reduced skin temperature
Reduce sensation
Prolonged capillary refill time (more than 2 seconds)
Changes during Buerger’s test
Test for assessing PAD in the leg?
Buerger’s test
What does the Buerger’s test consist of?
The first part involves the patient lying on their back (supine). Lift the patient’s legs to an angle of 45 degrees at the hip. Hold them there for 1-2 minutes, looking for pallor. Pallor indicates the arterial supply is not adequate to overcome gravity, suggesting peripheral arterial disease. Buerger’s angle refers to the angle at which the leg is pale due to inadequate blood supply. For example, a Buerger’s angle of 30 degrees means that the legs go pale when lifted to 30 degrees.
The second part involves sitting the patient up with their legs hanging over the side of the bed. Blood will flow back into the legs assisted by gravity. In a healthy patient, the legs will remain a normal pink colour. In a patient with peripheral arterial disease, they will go:
Blue initially, as the ischaemic tissue deoxygenates the blood
Dark red after a short time, due to vasodilation in response to the waste products of anaerobic respiration
The dark red colour is referred to as rubor.
Leg ulcers indicate?
the skin and tissues are struggling to heal due to impaired blood flow. Some features help you distinguish between arterial and venous ulcers.
Arterial ulcers are caused by ischaemia secondary to an inadequate blood supply. Typically, arterial ulcers:
Are smaller than venous ulcers
Are deeper than venous ulcers
Have well defined borders
Have a “punched-out” appearance
Occur peripherally (e.g., on the toes)
Have reduced bleeding
Are painful
Venous ulcers are caused by impaired drainage and pooling of blood in the legs. Typically, venous ulcers:
Occur after a minor injury to the leg
Are larger than arterial ulcers
Are more superficial than arterial ulcers
Have irregular, gently sloping borders
Affect the gaiter area of the leg (from the mid-calf down to the ankle)
Are less painful than arterial ulcers
Occur with other signs of chronic venous insufficiency (e.g., haemosiderin staining and venous eczema)
Investigations for PAD?
Ankle-brachial pressure index (ABPI)
Duplex ultrasound – ultrasound that shows the speed and volume of blood flow
Angiography (CT or MRI) – using contrast to highlight the arterial circulation
what is the Ankle-Brachial Pressure Index?
Ankle-brachial pressure index (ABPI) is the ratio of systolic blood pressure (SBP) in the ankle (around the lower calf) compared with the systolic blood pressure in the arm. These readings are taken manually using a Doppler probe. For example, an ankle SBP of 80 and an arm SBP of 100 gives a ratio of 0.8 (80/100).
Results:
0.9 – 1.3 is normal
0.6 – 0.9 indicates mild peripheral arterial disease
0.3 – 0.6 indicates moderate to severe peripheral arterial disease
Less than 0.3 indicates severe disease to critical ischaemic
An ABPI above 1.3 can indicate calcification of the arteries, making them difficult to compress. This is more common in diabetic patients.
Management of Intermittent Claudication: lifestyle
Lifestyle changes are required to manage modifiable risk factors (e.g., stop smoking). Optimise medical treatment of co-morbidities (such as hypertension and diabetes).
Exercise training, involving a structured and supervised program of regularly walking to the point of near-maximal claudication and pain, then resting and repeating.
Management of Intermittent Claudication: medical treatment?
Atorvastatin 80mg
Clopidogrel 75mg once daily (aspirin if clopidogrel is unsuitable)
Naftidrofuryl oxalate (5-HT2 receptor antagonist that acts as a peripheral vasodilator)
Surgical options for management of intermittent claudication?
Endovascular angioplasty and stenting
Endarterectomy – cutting the vessel open and removing the atheromatous plaque
Bypass surgery – using a graft to bypass the blockage
Endovascular angioplasty and stenting involve inserting a catheter through the arterial system under x-ray guidance. At the site of the stenosis, a balloon is inflated to create space in the lumen. A stent is inserted to keep the artery open. Endovascular treatments have lower risks but might not be suitable for more extensive disease.
Management of Critical Limb Ischaemia
Patients with critical limb ischaemia require urgent referral to the vascular team. They require analgesia to manage the pain.
Urgent revascularisation can be achieved by:
Endovascular angioplasty and stenting
Endarterectomy
Bypass surgery
Amputation of the limb if it is not possible to restore the blood supply
Management of Acute Limb Ischaemia
Patients with acute limb ischaemia need an urgent referral to the on-call vascular team for assessment.
Management options include:
Endovascular thrombolysis – inserting a catheter through the arterial system to apply thrombolysis directly into the clot
Endovascular thrombectomy – inserting a catheter through the arterial system and removing the thrombus by aspiration or mechanical devices
Surgical thrombectomy – cutting open the vessel and removing the thrombus
Endarterectomy
Bypass surgery
Amputation of the limb if it is not possible to restore the blood supply
