Diagnosis

• Provoked DVT: within 3 mths surgery, trauma, bed bound, pregnancy, hormone therapy (OCP, HRT)
• Unprovoked DVT: none of above factors NOR active cancer, thrombophilia, or VTE Fx
• If patient presents with signs or symptoms of PE, conduct Hx, Exam, Chest X ray
• If both DVT and PE suspected base choice of diagnostic test on clinical judgement

Investigation

DVT

• Wells score (two-level) >= 2 (see below), then DVT likely, and offer either:
  • Proximal leg vein ultrasound within 4 hrs, and if negative a D-dimer test, OR
  • D-dimer test and 24 hr dose of parenteral anti-coagulant, and proximal USS within 24hrs, if ultrasound cannot be carried out within 4 hrs
• Repeat proximal leg vein ultrasound in 6-8 days
• Wells score (two level) <= 1, then DVT unlikely, and offer a D-dimer test. If positive either:
  • Proximal leg ultrasound within 4 hrs
  • Interim 24hr dose of parenteral anti-coagulant and proximal USS within 24 hrs
• Diagnose and treat DVT if proximal vein USS is positive
• Take into account other diagnoses if all tests negative, or if only D-dimer raised in Wells <= 1

Pulmonary Embolism

• Wells PE score (two level) * 4 (see below), then PE likely and offer CTPA, or parenteral anti-coagulation and CTPA when available, consider proximal vein USS if CTPA negative
• Wells PE score (two level) <= 4, then PE unlikely then offer a D-dimer and if positive CTPA, or parenteral anti-coagulation and CTPA when available
• If renal impairment or contrast allergy consider V/Q SPECT or V/Q planar scan if not available, and parenteral anti-coagulation in the interim
• Diagnose and treat if any of the above are positive
• Take into account other diagnoses if all tests negative, or if only D-dimer raised in Wells PE <= 4
• Only offer thrombophilia screening (anti-phospholipid, hereditary thrombophilia) if unproved DVT/PE and intending to stop anti-coagulation therapy
• Offer cancer screening to all patients with unprovoked DVT / PE not known to have cancer: Exam, Chest X ray, Urinalysis, blood test

Management

Pharmacological treatment:

• LMWH or Fondaparinux or Unfractionated heparin (f eGFR < 30)
• Treat for 5 days at treatment dose or until INR is * 2 for 24 hrs whichever is longer
• If haemodynamically unstable offer Unfractionated heparin and consider thrombolytic therapy
• Vitamin K Antagonist (Warfarin) for 3 mths (within 24 hrs) if DVT / PE confirmed
• Vitamin K Antagonist (Warfarin) * 3mths if unprovoked or likely recurrence, no additional bleed risk
• If active cancer and DVT or PE offer LMWH for min 6 mths

Thrombolytic therapy

(Note anti-coagulants stop clot growing, not dispersion)

• Offer if good functional status and life expectancy * 1 yr, and low bleed risk

Mechanical intervention:

• Offer below knee compression stockings if ankle pressure * 23 mm Hg, once swelling reduced, wear for 2yr, only affected leg
• Vena caval filters to those who cannot have anti-coagulation treatment, or those with recurrent PE after consider INR range 3-4 instead

Wells Two-Level DVT Score >2 PE Likely (NICE)

Clinical probability simplified score

• DVT likely: 2 points or more
• DVT unlikely: 1 point or less

Wells Two-Level PE Score >4 PE Likely (NICE)

NICE Source: CG144 Venous thromboembolic diseases: diagnosis, management and thrombophilia testing. Summary compiled by Dr D P Sheppard MBBS.