Peripheral vascular disease or peripheral arterial disease (PAD) occurs when we have stenosis of the peripheral arteries, causing ischaemia to these areas.
PAD has 3 main presentations
- Intermittent claudication
- Critical limb ischaemia
- Acute limb ischaemia
Pathophysiology
It is typically caused by atherosclerosis and sometimes vasculitis, affecting the peripheries (mainly lower limbs).
⚠️ Risk factors
NON-MODIFIABLE RISK FACTORS
- Increasing age
- Family history
- Male
MODIFIABLE RISK FACTORS
- Obesity
- Hyperlipidaemia
- Alcohol
- Smoking
- Sedenterism
Medical co-morbidities such as hypertension, diabetes, CAD, RA also may lead to increased risk of atherosclerosis (and subsequent PAD).
😷 Presentation
Intermittent claudication is essentially angina in the legs. The patient may feel a crampy, achey pain in the calf, thigh or buttocks when exerting themselves. Upon resting the pain will disappear and not reappear unless the patient continues to walk. The distance is usually predictable (the “claudication distance”).
🔍 Investigations
Chronic limb ischaemia includes claudication (stage II), but it’s severity may progress to ischaemic rest pain (stage III), and ulceration/gangrene (stage IV).
Let’s look at the Fontaine classification of chronic limb ischaemia:
Stage I | Asymptomatic |
Stage II | Intermittent claudication |
Stage III | Ischaemic rest pain |
Stage IV | Ulceration/gangrene (or both) |
😷 Presentation
- Claudication is one of the early signs of course.
- Ischaemic rest pain >2 weeks
- Ischaemic lesions such as ulcers or gangrene
- Thickened nails may also be a sign
If a patient has PAD they are likely to have IHD and other CVS issues (3x more likely to die from CVS issues).
Severity | ABPI |
Normal | >0.9 |
Mild | 0.8-0.9 |
Moderate | 0.5-0.8 |
Severe | <0.5 |
🔍 Investigations
🏆ABPI <0.5 A full CVS assessment should also be done (ECG, BP, glucose, lipid profile).
CT or MRA may also prove useful, especially for iliac and aorta. 🏆 Catheter angiography is the gold-standard for viewing vessels.
Management
- Diabetic control
- Smoking cessation
- Dietary modifications
- Obesity management
- Exercise programme
- Atarvostatin - 80mg OD
- Adverse effects: muscle cramps
- Clopidogrel - 75mg OD
Drugs licensed for use in peripheral arterial disease (PAD) include:
- Naftidrofuryl oxalate - vasodilator, sometimes used for patients with a poor quality of life and when a supervised exercise programme has not led to satisfactory improvement in their symptoms, or when the patient refuses to consider percutaneous or surgical management.
- Angioplasty ± stenting - NICE recommends this type of surgery in preference to bypass surgery for patients with short segment stenosis (<10cm) as it is less invasive.
- Bypass grafting - it is a more invasive surgery and so would be reserved for more diffuse disease, or with stenosis >10cm.
Amputation may be considered in a patient unsuitable for revascularisation.
🚨 Complications
- Sepsis - 2º to infected gangrene.
- Acute limb ischaemia
- Amputation
This is the sudden decrease of perfusion to a limb which can cause it to be unviable.
Pathophysiology
It is essentially a “limb attack” and the causes are similar to an MI:
- Embolus
- Thrombosis in situ
- Trauma - as seen in compartment syndrome but this is less common.
😷 Presentation
- Pain
- Pallor
- Pulseless
- Paralysis
- Paraesthesia
- Perishing cold
The viability of the tissue needs to be assessed. We can rank it according to 4 categories (I, IIA, IIB, III) to assess the prognosis of the tissue:
Category | Prognosis | Sensory Loss | Motor Deficit | Arterial Doppler | Venous Doppler |
I – Viable | No Immediate threat | None | None | Audible | Audible |
IIA – Marginally Threatened | Salvageable, if promptly treated | Minimal (toes) or none | None | Inaudible | Audible |
IIB – Immediately Threatened | Salvageable if immediately revascularised | More than toes, rest pain | Mild/Moderate | Inaudible | Audible |
III – Irreversible | Major tissue loss, permanent nerve damage inevitable | Profound | Profound, paralysis | Inaudible | Inaudible |
🔍 Investigations
- Serum lactate as this gives an idea of the ischaemia levels.
- G&S will also be useful.
- ECG is also necessary as acute limb ischaemia may be due to AF or recent MI embolus.
🥇 Doppler ultrasound
🏆 CT angiography should also be considered, especially if the limb is salvageable, to aid operation.
🧰 Management
It is a surgical emergency. Within 6 hours there will be irreversible tissue damage.
→ 🥇 Heparin (therapeutic dose should be given as soon as possible). A prolonged course of heparin may be useful in category I or IIa patients who are not suitable for surgery.
🚨 Complications
- Ischaemia reperfusion syndrome - sudden increase in capillary permeability leads to:
- Compartment syndrome
- Damaged myocytes also release:
- K+ → hyperkalaemia
- H+ → acidosis
- Myoglobin → AKI