PAD

• 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
• PAD is the end result of atherosclerosis
• Non-modifiable risk factors:

  • Older age
  • Family history
  • Male
• Modifiable risk factors:

  • Smoking
  • Alcohol consumption
  • Poor diet
  • Obesity
• Medical Co-Morbidities

  • Diabetes
  • Hypertension
  • Chronic kidney disease
  • Inflammatory conditions such as rheumatoid arthritis
• 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 as the femoral artery is the most commonly affected by atherosclerosis, but it can also affect the thighs and buttocks.
• Leriche syndrome:

  • Result of progressive aortoiliac occlusion (doesn't happen acutely)
  • Thigh / buttocks claudation
  • Absent femoral pulse
  • Male impotence
• Signs of PAD:

  • Tar staining
  • Xanthomata
  • CABG scars
  • Previous amputations
  • Weak peripheral pulses
• 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)
• Buerger's test - arterial supply is not sufficient enough to over come gravity. Legs will go blue (as ischaemic tissue deoxygenates the blood) and eventually a deep red colour = dependent rubor (vasodilation in response to the waste products of anaerobic respiration)
• Investigations

  • Ankle-brachial pressure index (ABPI) - compare systolic blood pressure in ankle to arm
  • Duplex ultrasound – ultrasound that shows the speed and volume of blood flow
  • Angiography (CT or MRI) – using contrast to highlight the arterial circulation
• Management of intermittent claudication:

  • life style modification and exercise training
  • maximise treatment of co-morbidities
  • Atorvastatin 80mg
  • Clopidogrel 75mg
  • Naftidrofuryl oxalate (5-HT2 receptor agonist) - acts as a peripheral vasodilator
• Acute limb ischaemia is a medical emergency - the 6 Ps

  1. Pain
  2. Pallor
  3. Pulseless
  4. Paralysis
  5. Paraesthesia
  6. Perishing cold
• 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:

  • Ankle-brachial pressure index (ABPI)
  • Duplex ultrasound
  • Angiography (CT or MRI) - uses contrast to highlight the arterial circulation
• Surgical management of intermittent claudication:

  • Endovascular angioplasty and stenting
  • Endarterectomy - cutting the vessel open and removing the atheromatous plaque
  • Bypass surgery
• critical limb ischaemia:

  • ABPI <0.5
  • Ischaemic rest pain for greater than 2 weeks duration - requiring opiate analgesia
  • Presence of ischaemic lesions or gangrene
  • Pale, cold limb with weak or absent pulses
• Management of critical limb ischaemia:

  • Urgent referral to the vascular team
  • Analgesia
  • Urgent revascularisation by:
  • Endovascular angioplasty and stenting
  • Endarterectomy
  • Bypass surgery
  • Amputation of the limb if it is not possible to restore the blood supply
• Complications:

  • Sepsis - secondary to infected gangrene
  • Acute-on-chronic ischaemia
  • Amputation
  • Reduced mobility and quality of life
  • The 5 year mortality rate in those diagnosed with chronic limb ischaemia is around 50%
• End Results of Atherosclerosis

  • Angina
  • Myocardial infarction
  • Transient ischaemic attack
  • Stroke
  • Peripheral arterial disease
  • Chronic mesenteric ischaemia
• Doppler ultrasound:

  • Triphasic = normal blood flow
  • Monophasic = reduced blood flow e.g. PAD - blood passing through point of occlusion slows down
• Two important differentials of PAD:

  • Spinal stenosis - causes neurogenic claudication - worsening by position and not relieved by rest
  • Acute limb ischaemia - symptoms present for less than 2 weeks