VTE Prophylaxis and Management

VTE Basics & Risk - Spotting Clot Danger

• VTE: Spectrum of diseases from Deep Vein Thrombosis (DVT) to Pulmonary Embolism (PE).

• Virchow's Triad (Pathogenesis): 📌 SHE (Stasis of blood flow, Hypercoagulability, Endothelial injury).

• Key Risk Factors for VTE:

  • Inherited thrombophilias: Factor V Leiden, Prothrombin G20210A mutation, Protein C/S deficiency, Antithrombin deficiency.
  • Acquired states: Major Surgery (esp. orthopedic), Trauma, Prolonged Immobility, Active Malignancy, Pregnancy/Postpartum, OCPs/HRT, Advanced Age (>60), Obesity (BMI >30 kg/m²).

• Risk Stratification Scores (Purpose):

  • Padua Prediction Score: Identifies high-risk medical inpatients needing prophylaxis.
  • Caprini Score: Guides VTE prophylaxis decisions in surgical patients.

⭐ Factor V Leiden is the most common inherited thrombophilia in Caucasian populations, predisposing to DVT.

VTE Prophylaxis - Shielding from Clots

Primary Goal: Prevent VTE development in hospitalized or at-risk individuals.

• Pharmacological Prophylaxis:
  • LMWH: Enoxaparin 40mg SC OD; 30mg SC BD in specific orthopedic surgery.
  • UFH: 5000U SC BD/TDS.
  • Fondaparinux: 2.5mg SC OD.
  • DOACs (esp. post-ortho): Rivaroxaban 10mg OD, Apixaban 2.5mg BD.
• Mechanical Prophylaxis:
  • Graduated Compression Stockings (GCS), Intermittent Pneumatic Compression (IPC) devices.
  • Indicated when anticoagulants are contraindicated (e.g., high bleeding risk).
• Contraindications to Anticoagulation:
  • Active major bleeding, severe thrombocytopenia (<50,000/µL), recent major surgery at a critical site (e.g., intracranial, spinal).

⭐ For patients with CrCl <30 mL/min, UFH or dose-adjusted LMWH is preferred for prophylaxis.

VTE Diagnosis - Finding Hidden Clots

DVT Diagnosis:

• Symptoms: Unilateral leg swelling, pain, warmth, erythema. Homan's sign (unreliable).
• Algorithm:
  • Pre-test probability: Wells (DVT: L <1, M 1-2, H >2).
  • D-dimer: If Wells low/moderate.
  • Compression Ultrasound (CUS): Primary tool.

PE Diagnosis:

• Symptoms: Dyspnea, pleuritic chest pain, cough, hemoptysis, tachycardia, syncope.
• Algorithm:
  • Pre-test probability: Wells (PE: L <2, M 2-6, H >6), Geneva.
  • PERC rule: Low PTP & 8 PERC criteria neg → PE out.
  • D-dimer: If PERC+ or mod PTP.
  • CT Pulmonary Angiography (CTPA): Gold standard.
  • V/Q scan: If CTPA C/I.
• ECG: S1Q3T3 (classic, rare).
• CXR: Often normal; Westermark, Hampton's.

⭐ A negative PERC rule in a low-risk patient for PE obviates the need for D-dimer testing.

VTE Management - Active Clot Combat

• Principles: Anticoagulation mainstay. Rapid initiation.
• DVT:
  • Proximal: LMWH/UFH/Fondaparinux → VKA (target INR 2-3), OR DOAC monotherapy (e.g., Rivaroxaban, Apixaban - loading/maintenance doses).
• PE:
  • Risk Stratify: PESI/sPESI score, hemodynamics.
  • Low-Risk PE: Anticoagulation (as for DVT).
  • Massive PE (High-Risk, Unstable): Systemic thrombolysis (e.g., Alteplase 100mg IV over 2h). Alternatives: catheter-directed lysis, surgical embolectomy.
  • Submassive PE (Intermediate-Risk, Stable + RV dysfunction/necrosis): Anticoagulation. Consider thrombolysis if deteriorating.
• Duration of Anticoagulation:
  • Provoked VTE (transient risk factor): 3 months.
  • Unprovoked VTE/Ongoing risk (e.g., cancer): Extended/indefinite.
• IVC Filters: Limited role (e.g., absolute anticoagulation contraindication with proximal DVT/PE).

⭐ For cancer-associated thrombosis (CAT), LMWH or DOACs (Edoxaban, Rivaroxaban, Apixaban) are preferred over VKAs.

High‑Yield Points - ⚡ Biggest Takeaways

• Wells score is vital for DVT/PE pre-test probability.
• D-dimer helps exclude VTE in low clinical probability cases.
• LMWH (e.g., Enoxaparin) is standard for VTE prophylaxis in medical inpatients.
• Unprovoked VTE requires anticoagulation for ≥3-6 months, often extended.
• DOACs are increasingly first-line for VTE treatment, preferred over Warfarin.
• Massive PE with hemodynamic instability needs urgent thrombolysis or embolectomy.
• IVC filters for acute VTE if anticoagulation is absolutely contraindicated_