Arterial Thrombosis

Blood clot which forms in an artery

Aetiology

Risk factors

Factors that cause damage to endothelium, increase in foamy macrophages and platelet activation:
  • Hypertension
  • Smoking
  • High cholesterol
  • Diabetes mellitus

Pathophysiology

Atherosclerosis

  • Damage to endothelium causes recruitment of ‘foamy’ macrophages rich in cholesterol, resulting in the formation of cholestrol-rich plaques
  • Stable plaques result in stable angina and intermittent claudication
  • Unstable plaques result in stroke, unstable angina or myocardial infarction
    • Plaques rupture, platelets are recruited and cause acute thrombosis → sudden onset of symptoms
    • Leads to acute organ ischaemia and infarction

Platelets and arterial thrombosis

  1. Plaque ruptures - more likely in the high pressure environment of arteries
  1. Exposed endothelium and release of Von Willebrand factor and other proteins to which platelets have receptors → platelet adhesion to the site of injury
  1. Platelets become activated - release granules that activate coagulation and recruit other platelets to developing platelet plug (e.g. ADP, thrombin, and thromboxane A2)
  1. Platelet aggregation via membrane glycoproteins (GPIIbIIa and fibrinogen)

Clinical presentation

  • As stroke/ACS

Investigations

  • See stroke/ACS

Management

  • Aspirin and other anti-platelet drugs
  • Modify risk factors for atherosclerosis
    • Stop smoking, treat hypertension, treat diabetes, lower cholesterol