Table 2.

Thrombotic assessment

Thrombotic risk
HighModerateLow
Mechanical heart valve
  • Any mechanical mitral valve

  • Older mechanical valve model aortic valve (caged ball/tilting disc)

  • Recently placed mechanical valve (<3 months)

  • Recent stroke or TIA (within 6 months)

Bi-leaflet aortic valve and one of the following:
  • AF,

  • previous stroke/TIA,

  • hypertension,

  • diabetes,

  • heart failure,

  • age >75 years.

  • Bi-leaflet aortic valve without AF and no other risk factors for stroke

Atrial fibrillation
  • With mechanical heart valve

  • With rheumatic fever

  • With recent stroke or TIA (<3 months)

  • CHADS score 5 or 6

CHADS score of 3 or 4CHADS score 0–2 (no previous TIA/Stroke)
Venous thromboembolism
  • VTE with previous 3 months

  • With severe thrombophilia (Protein C, S or Antithrombin III deficiency, Homozygous factor V Leiden mutation)

  • VTE 3–12 months ago

  • Recurrent VTE

  • With non-severe thrombophilia (Heterozygous factor V Leiden mutation)

Single VTE >12 months ago and no other risk factors
  • AF = atrial fibrillation; CHADS = congestive cardiac failure, hypertension, age of 75 years or older, diabetes or previous stroke or TIA; TIA = transient ischaemic attack; VTE = venous thromboembolism.

  • Adapted with permission from Douketis et al.33