Venous Thromboembolism (VTE) - General Flashcards
Why can a VTE cause a stroke?
An ASD can allow a thrombus to bypass the pulmonary circulation and enter the systemic circulation.
Risk Factors of VTE (9).
- Immobility.
- Recent Surgery (60-90 Minutes+).
- Long-Haul Travel.
- Pregnancy.
- Hormone Therapy with Oestrogen (COCP + HRT).
- Malignancy.
- Polycythaemia.
- SLE.
- Thrombophilia.
Give 7 Thrombophilias.
- ANTIPHOSPHOLIPID SYNDROME (recurrent miscarriage).
- Factor V Leiden (commonest).
- Antithrombin III Deficiency.
- Protein C/S Deficiency.
- Hyperhomocysteinaemia.
- Prothrombin Gene Variant (2nd commonest)
- Activated Protein C Resistance.
Medication Risk Factors of VTE.
- COCP - especially 3rd Generation.
- HRT - especially bihormonal.
- Raloxifene + Tamoxifen.
- Antipsychotics.
VTE Prophylaxis.
Anyone at risk - prophylaxis with LMWH e.g. Enoxaparin or Fondaparinux Sodium (SC) and anti-embolic compression stockings.
Contraindications for LMWH (2).
- Active Bleeding.
2. Existing Coagulation with Warfarin or DOAC.
Contraindication for anti-embolic compression stocking.
Peripheral arterial disease.
Differential Diagnoses for D-Dimer Raise (6).
- VTE - DVT.
- Pneumonia.
- Malignancy.
- Surgery.
- Heart Failure.
- Pregnancy.
Initial Management of VTE.
Anticoagulation with DOACs e.g. Apixaban or Rivaroxaban (immediately if suspected).
Long-Term Medical Management of VTE (4).
- DOAC or Warfarin or LMWH.
- LMWH is 1st line in Pregnancy.
- Warfarin is 1st line in Antiphospholipid Syndrome (with initial concurrent treatment with LMWH) and target INR is between 2-3.
- Continue anticoagulation for 3 months (reversible cause), 3-6 months (active cancer), 3+ months (unclear cause, recurrent VTE, irreversible underlying cause e.g. thrombophilia).
- Use HAS-BLED Score to compare benefits vs. risk of bleeding.
Investigations of Unprovoked VTE (3).
- Review History, Baseline Bloods, Physical Exam for Cancer.
- Test for Antiphospholipid Syndrome (Antiphospholipid Antibodies).
- Test for Hereditary Thrombophilias (only 1st Degree Relative also affected by VTE).
Additional Management in VTE.
- Percutaneous Massive Thrombectomy (Massive DVT).
2. IVC Filter (Reduced Risk of PE, but contraindication : Anticoagulation).
What is Budd-Chiari Syndrome?
Thrombosis in the Hepatic vein, to cause acute hepatitis : triad of abdominal pain, hepatomegaly, ascites.
Management of Budd-Chiari Syndrome (2).
- Anticoagulation (Heparin, Warfarin).
2. Treatment of Underlying Cause of Hypercoagulable State and Treatment of Hepatitis.
Post-Procedure Prophylaxis VTE - Elective Hip (3).
- LMWH 10 Days + Aspirin for 28 Days.
- LMWH + Anti-Embolism Stockings for 28 Days.
- Rivaroxaban.
Post-Procedure Prophylaxis VTE - Elective Knee.
- Aspirin 14 Days.
- LMWH for 14 Days + Anti-Embolism Stockings.
- Rivaroxaban.
Post-Procedure Prophylaxis VTE - Fragility Fracture.
1 Month if VTE Risk outweighs risk of bleeding with LMWH 6-12 hours after surgery or Fondaparinux Sodium 6 hours after surgery.
Indications of LMWH and Fondaparinux (2).
- VTE - LMWH is 1st line prophylaxis and initial treatment.
2. ACS - 1st line therapy to improve revascularisation and prevent intracoronary thrombus progression.
Mechanism of Action of LMWH and Fondaparinux (3).
- Unfractionated Heparin (UFH) activates Antithrombin - to inactivate clotting factor Xa and Thrombin.
- LMWH preferentially inhibit factor Xa.
- Fondaparinux inhibits factor Xa only.
Cautions of LMWH and Fondaparinux (5).
- Clotting Disorders.
- Severe Uncontrolled Hypertension.
- Recent Surgery/Trauma.
- Invasive Procedures e.g. Lumbar Puncture and Spinal Anaesthesia.
- Renal Impairment (use lower dose or UFH).
Adverse Effects of LMWH and Fondaparinux.
- Bleeding (slightly lower with Fondaparinux).
- Injection Site Reaction.
- Heparin-Induced Thrombocytopenia (more with UFH).
