Venous Thromboembolism (VTE) Overview

Key Concepts

• VTE includes:
  • Deep Vein Thrombosis (DVT)
  • Pulmonary Embolism (PE)

Deep Vein Thrombosis (DVT)

Pathophysiology

• Thrombus Formation: Clot develops within veins, primarily in legs.
• Vein Classification:
  • Proximal DVT: Femoral, iliac, popliteal veins.
  • Distal DVT: Tibial, peroneal veins.

Virchow's Triad

1. Stasis of Blood Flow:
   • Causes include post-op states, immobility, long travels.
2. Endothelial Injury:
   • Caused by smoking, surgical procedures, venous catheters.
3. Hypercoagulability:
   • Increased pro-coagulants and decreased anticoagulants.
   • Triggers include malignancy, pregnancy, oral contraceptives, genetic mutations, anti-phospholipid syndrome, heparin-induced thrombocytopenia.

Presentation

• Symptoms include leg pain, swelling, positive Homan's sign (caution advised).

Complications

• Phlegmasia Cerulea Dolens: Severe congestion, bluish limb.
• Phlegmasia Alba Dolens: Severe congestion, pale limb due to arterial compression.
• Post-Thrombotic Syndrome: Chronic insufficiency after clot.
• Pulmonary Embolism (PE): Clot travels to the lungs.

Diagnosis

• Wells Score: Determines DVT probability.
• D-Dimer Test: If negative and low score, likely no DVT.
• Ultrasound: Confirmatory for DVT presence.

Treatment

• Proximal DVT: Anticoagulation; thrombectomy or TPA for severe cases.
• Distal DVT: Observation or anticoagulation based on severity.
• Underlying Cause: Identifying and treating the cause is crucial to prevent recurrence.

Pulmonary Embolism (PE)

Causes

• Mnemonic 'FATAL':
  • Fat, Air, Thrombus, Amniotic, Septic emboli.
• DVT is the most common cause.

Presentation

• Symptoms include dyspnea, pleuritic chest pain, hemoptysis.

Complications

• Respiratory Failure: Due to VQ mismatch.
• Obstructive Shock: Right heart strain and failure, jugular venous distension.
• Common findings: dyspnea, tachycardia, hypoxemia, hypotension.

Diagnosis

• Initial Tests: Chest X-ray, EKG (look for S1Q3T3, sinus tachycardia).
• Wells Criteria for PE: Helps determine risk and next steps.
• PERC Score: Rules out PE in low-risk patients.
• D-Dimer Test: Elevated levels prompt further imaging.
• CTPA or VQ Scan: Confirms PE.
• Echocardiogram: Determines RV dysfunction for risk assessment.

Treatment

• Anticoagulation: For stable patients.
• TPA or Embolectomy: For hemodynamically unstable patients.

Prevention

• Hospitalized Patients: Use of pharmacological prevention (Heparin) and mechanical devices (compression sleeves) to prevent VTE in immobile patients.

These notes summarize the key points from a lecture on VTE, focusing on DVT and PE, their pathophysiology, diagnosis, treatment, and prevention strategies.