Table Of Contents

Deep Vein Thrombosis (DVT) Overview

Watch ▶Deep vein thrombosis and pulmonary embolism: Pathology review

Watch ▶Deep vein thrombosis: Clinical sciences

Definition

• Formation of a blood clot within a deep vein ⇒ Commonly in the legs.

Locations

• The deep veins of the lower extremities are the most frequent source.

<aside> 🚨

Lower extremity deep vein thrombosis (DVT) is divided into 2 categories:

• Proximal/thigh (eg, iliac, femoral, popliteal) ⇒ These DVTs are the source of >90% of acute PEs, probably due to their large caliber and proximity to the lungs.
• Distal/calf ⇒ Although most DVTs occur in the calf vein, distal/calf DVTs are less likely than proximal/thigh DVTs to embolize to the lungs and cause PE and they are more likely to spontaneously resolves </aside>

Risk Factors

• Virchow's Triad

  • Endothelial injury
  • Venous stasis
  • Hypercoagulability

• Hypercoagulability Risks

  • Cancer
  • Surgery
  • Obesity
  • Smoking
  • Oral contraceptive pills (OCPs)
  • Pregnancy
  • Genetic
  • Autoimmune thrombophilia

Clinical Presentation

• Approximately 50% of patients present with
  • Calf pain
  • Tenderness
  • Erythema
  • Superficial vein dilatation
• Homan's Sign
  • Calf pain on ankle dorsiflexion

Diagnosis

• Imaging

  • Lower extremity ultrasound (US)

• Risk Stratification

  • Utilize the Modified Wells criteria for deep vein thrombosis

  Criteria	Score
  Active cancer	+ 1
  Previously documented DVT	+ 1
  Paralysis, paresis, or recent (cast) immobilization of lower extremity	+ 1
  Recently bedridden for ≥ 3 days OR underwent major surgery within the past 12 weeks under general/local anesthesia	+ 1
  Tenderness localized along the deep venous system	+ 1
  Swelling of the entire leg	+ 1
  Calf swelling ≥ 3 cm compared to the contralateral leg	+ 1
  Pitting edema confined to the symptomatic leg	+ 1
  Distended collateral superficial veins (non-varicose)	+ 1
  Alternative diagnosis as likely as or more likely than DVT	- 2

<aside> 1️⃣

Interpretation (pretest probability for DVT)

• 0 → low
• 1–2 → intermediate
• ≥ 3→ high </aside>

<aside> 2️⃣ Diagnostic Approach Based on Probability

• Low probability
  • Perform D-dimer test
    • If elevated → ultrasound
• Moderate/High probability
  • Directly proceed with ultrasound. </aside>

Management

Very High Yield

• Initial Management

  Focus on the difference between proximal and distal

  1. Proximal DVT
     • Anticoagulation
       • Heparin
       • Warfarin
       • Low Molecular Weight Heparin (LMWH)
       • Direct Oral Anticoagulants (DOACs)

  <aside> ⛔ if there is Contraindications to Anticoagulation

  • Inferior Vena Cava (IVC) filter placement
    • IVC filter illustration </aside>

  1. Massive Proximal DVT

     Defined by severe swelling, soft tissue ischemia, etc.

     • Consider thrombolytic therapy or surgical thrombectomy

  2. Distal DVT

     • Anticoagulation
       • If contraindicated → observe closely with lower extremity ultrasound

• Follow-Up

  • Work-up for underlying causes if unknown
    • Age-appropriate cancer screening
      • If young, consider hereditary thrombophilia panel

• UWA - Management of lower extremity proximal DVT

<aside> ⏱️ Anticoagulation Duration

• Typically 3 months
• Continue indefinitely if the cause is unknown or irreversible </aside>

DVT overview

Complications

• Phlegmasia Cerulea Dolens

Prevention (VTE prophylaxis)