What should be included in the assessment of a patient with a Deep Vein Thrombosis (DVT)?

Assessment of a Patient with Deep Vein Thrombosis (DVT)

The assessment of a patient with suspected DVT should begin with clinical probability assessment using the Wells score, followed by D-dimer testing for low-probability patients and compression ultrasonography for high-probability patients. 1

Clinical Probability Assessment

The Wells score is the recommended tool for clinical probability assessment:

Factor	Points
Active cancer	1
Paralysis, paresis, or recent immobilization	1
Bedridden ≥3 days or major surgery within 12 weeks	1
Localized tenderness along deep veins	1
Entire leg swollen	1
Calf swelling ≥3 cm larger than asymptomatic side	1
Pitting edema confined to symptomatic leg	1
Collateral superficial veins	1
Previous DVT	1
Alternative diagnosis at least as likely	-2

• Score interpretation:
  • ≥2 points: DVT likely
  • <2 points: DVT unlikely

Diagnostic Algorithm

For Patients with "DVT Unlikely" (Wells score <2):

1. Order D-dimer testing
   • If negative: DVT excluded
   • If positive: Proceed to compression ultrasonography (CUS)

For Patients with "DVT Likely" (Wells score ≥2):

1. Proceed directly to compression ultrasonography (CUS)
   • If positive: Treat for DVT
   • If negative: Consider additional testing with D-dimer, serial ultrasound, or venographic-based imaging 2

Special Considerations

• For patients with conditions causing elevated D-dimer (cancer, inflammation, pregnancy, recent surgery):

  • Begin with ultrasound rather than D-dimer testing 1

• For negative proximal CUS but high clinical suspicion:

  • Consider imaging the iliac veins to exclude isolated iliac DVT 2
  • Consider serial ultrasound (repeat in 1 week) 2
  • Consider whole-leg ultrasound 2

• When CUS is impractical (leg casting, excessive tissue):

  • Consider CT venography or MR venography as alternatives 1

Specific Elements to Assess

History

• Risk factors for DVT:
  • Active cancer
  • Recent immobilization or surgery
  • Previous DVT or thrombophilia
  • Hormone therapy
  • Recent trauma
  • Pregnancy or postpartum state
  • Age ≥75 years
  • Obesity (BMI ≥35 kg/m²)

Physical Examination

• Leg swelling (measure calf circumference)
• Pain with palpation along deep veins
• Erythema of affected limb
• Dilated superficial veins
• Pitting edema
• Pain when walking

Pitfalls to Avoid

1. Relying solely on clinical examination - Physical examination alone is only about 30% accurate for DVT 3

2. Missing isolated iliac vein thrombosis - Consider this when standard proximal CUS is negative but symptoms persist 1

3. Overlooking non-vascular causes of unilateral leg swelling (cellulitis, compartment syndrome, septic arthritis) 3

4. Delaying anticoagulation in high-risk patients - Consider prophylactic anticoagulation while awaiting definitive diagnosis 1

5. Failing to perform serial testing when initial tests are negative but clinical suspicion remains high 2

Treatment Considerations

When DVT is confirmed, anticoagulation should be initiated promptly with one of the following options 1:

• Direct oral anticoagulants (DOACs) without initial parenteral therapy (apixaban or rivaroxaban)
• Parenteral anticoagulant (LMWH) followed by dabigatran or edoxaban
• LMWH overlapped with warfarin

DOACs are generally preferred due to their effectiveness, safety profile, and convenience compared to warfarin 4.

By following this structured approach to DVT assessment, you can ensure accurate diagnosis and timely treatment, reducing the risk of complications such as pulmonary embolism and post-thrombotic syndrome.