Learning objectives

• Description and management of Factor V Leiden

Definition and mechanisms

• Factor V Leiden is an autosomal dominant inherited mutation of the F5 gene that controls the production of factor V, one of the clotting factors in the blood
• Resulting in resistance to activated protein C thereby leading to thrombosis
• It is the most common inherited blood clotting disorder 
• Factor V Leiden increases the chance of developing a deep vein thrombosis or pulmonary embolism
• However, most people with factor V Leiden never develop abnormal blood clots

Signs and symptoms

• The factor V Leiden mutation does not itself cause any symptoms and the first indication is the development of a blood clot
• Deep vein thrombosis
  • Pain
  • Swelling
  • Redness
  • Warmth
  • Tenderness
  • Abdominal pain
  • A severe, sudden headache and/or seizures
• Pulmonary embolism
  • Sudden shortness of breath
  • Chest pain when breathing in
  • A cough that produces bloody or blood-streaked sputum
  • Wheezing
  • Tachycardia
  • Feeling light-headed or fainting

Risk factors

• Immobility
• Intake of estrogen-based therapies
• Surgeries or injuries
• Non-O blood type

Diagnosis

• Activated protein C blood test
• Genetic testing

Management

• Anticoagulants are not routinely recommended for factor V Leiden
• If DVT or PE is diagnosed, anticoagulantherapy is started as soon as possible
• Consider that the patient:
  • May be on chronic anticoagulant therapy
  • Is at increased risk of perioperative  clotting events and need a DVT prophylaxis plan
• See pulmonary embolism

Suggested reading

• Shah UJ, Madan Narayanan M, J Graham Smith JH. 2015. Anaesthetic considerations in patients with inherited disorders of coagulation. Continuing Education in Anaesthesia Critical Care & Pain. 15;1 26-31.