Venous thromboembolism

• Venous Thromboembolism (VTE)


  • Condition where blood clot (thrombus containing fibrin + RBC's) form in venous circulation mostly in deep veins of legs or pelvis - Deep Vein Thrombosis (DVT)
  • Thrombi may dislodge, travel in blood - pulmonary arteries - Pulmonary Embolism (PE)
  • VTE = DVT + PE

  
• Venous thrombosis


  • 3 factors lead to fibrin rich clots:
  • Changes in blood composition
  • Decreased blood flow
  • Changes to vessels

  
• Clot formation


  1. Fibrin formed which cross links to form mesh trapping RB's + platelets forming a clot

  2. DVT if the clot is formed in large veins of legs or pelvis

  3. If clot breaks away and blocks artery in lungs —> Pulmonary Embolism (PE)
• Anticoagulants


  Target specific proteins in cascade to treat acute DVT & PE
• Risk factors for DVT


  • Age over 60 (common over 40)
  • Male sex
  • History of DVT or PE
  • Blood vessel damage
  • Conditions or treatments that cause blood to clot more easily - cancer, heart and lung disease, acquired or familial thrombophilia, hughes syndrome
  • Overweight or obese
  • Inflammatory disorders e.g. Vasculitis., inflammatory bowel disease

  
• Temporary risk factors that increase likelihood of DVT


  • Significant immobility
  • Significant trauma or direct trauma to a vein (intravenous catheter)
  • Combined contraceptive pill and hormone replacement therapy
  • Pregnancy, postpartum period
  • Dehydration

  
• The most serious complication of VTE is pulmonary embolism
• Provoked DVT or PE


  Occurs in person with recent (within 3 months) and transient major clinical risk factor for VTE such as surgery, trauma, significant immobility, pregnancy, puerperium, hormonal therapy

  
• Unprovoked DVT or PE


  Occurs without recent major clinical risk factors for VTE
• Symptoms of DVT


  • Pain, swelling and tenderness in one leg (usually the calf) - occasionally both legs
  • Heavy ache in affected area
  • Warm skin around the clot
  • Red skin, particularly at the back of the leg below the knee
  • Vein distension
  • Discolouration
  • Pitting oedema - excess fluid builds in body -> swelling
• Symptoms of PE


  • Breathlessness - gradual or sudden
  • Chest pain - may be worse when breathe in
  • Sudden collapse
  • Hypotension
  • Increased HR /Tachycardia
  • Cough
  • Low grade fever
• Diagnosis of DVT


  1. D-dimer blood test

  2. Ultrasound scan

  3. Venogram

  
• Diagnosis of PE


  1. General investigation - presenting symptoms inclusive of symptoms of PE and DVT plus assessment of patients general medication history, physical examination, chest x-ray to exclude other causes

  2. Computed tomography pulmonary angiogram (CTPA)

  
• Oral anticoagulants


  Apixaban, rivaroxaban are 1st line agents for confirmed, proximal, DVT or PE

  
• Oral anticoagulant dosing


  • Apixaban - 2.5mg X2 daily for surgery, 10mg X2 daily initially for treatment DVT or PE, 2.5mg once daily for prophylaxis
  • Rivaroxaban - 10mg once daily (usually around this dose for after surgery), 15mg X2 daily 21 days then maintenance 20mg once daily, 10mg Once daily for prophylaxis

  
• Alternative anticoagulant regimens


  • LMWH at least 5 days followed by Dabigatran or Edoxaban
  • LMWH with Vit K antagonist (VKA) at least 5 days until INR= 2.0 in 2 consecutive readings followed by VKA alone

  
• Role of pharmacist


  • Review doses for each individual considering different indications, extremes of body weight, level of renal impairment, current cancer, antiphospholipid syndrome
  • Advise on bleeding risk and when to seek medical advice
  • Provide counselling on anticoagulant treatment
• Treatment duration


  • Unprovoked DVT - continue beyond 3 months if low bleeding risk
  • Provoked DVT - consider stopping anticoagulant after 3 months if provoking factor no longer present and course has been uncomplicated
  • Recurrent DVT - long term treatment advised after risk assessment
• (2005) estimated 25,000 people dying from preventable hospital acquired VTE in the UK
• VTE assessment


  1. All patients in hospital undergo VTE assessment ASAP to determine if prophylaxis required

  2. Done by surgical doc, pre-op nurse, pre-op pharmacist (independent prescribers)

  3. Assess mobility, review thrombosis risk factors, review bleeding factors, clinical decision whether thromboprophylaxis and mechanical prophylaxis is required

  
• Medical patient VTE prophylaxis


  • LMWH (enoxaparin, dalteparin, tinzaparin)
  • Fondaparinux

  
• Surgical patient VTE prophylaxis


  • LMWH for longer duration
  • Some DOACs licensed after elective hip or knee replacement
• Mechanical prophylaxis


  Anti-embolic stockings, intermittent pneumatic compression
• Role of pharmacist in VTE prophylaxis


  • Advise on keeping hydrated, exercising, and mobility
  • Beware if patient not suitable for prophylaxis - MI patients treated with thrombolytics, stroke patients, current anticoagulation therapy
• Venous Thromboembolism (VTE)


  A condition where blood clots form in the venous circulation, most commonly in the deep veins of the legs or pelvis. VTE includes both Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE).
• Deep Vein Thrombosis (DVT)


  A blood clot that forms in the deep veins of the legs or pelvis. DVT is a type of Venous Thromboembolism (VTE).
• Pulmonary Embolism (PE)


  A blood clot that has traveled to the lungs and blocked one or more pulmonary arteries. PE is a type of Venous Thromboembolism (VTE).
• Fibrin


  A protein that helps to form a mesh-like structure in blood clots, trapping red blood cells and other components of the blood.
• Red Blood Cells (RBCs)


  Cells in the blood that carry oxygen to the body's tissues. RBCs are a key component of blood clots.
• Anticoagulant medications


  Medications used to prevent the formation of new clots and reduce the risk of existing clots growing larger. Anticoagulants are commonly used to treat Venous Thromboembolism (VTE).
• Thrombolytic medications


  Medications used to dissolve existing clots. Thrombolytics are typically reserved for severe cases of Venous Thromboembolism (VTE).
• Compression stockings


  Tight-fitting stockings that help to prevent the development of Deep Vein Thrombosis (DVT) by applying pressure to the legs and promoting blood flow.
• Risk factors for VTE


  Age, obesity, smoking, prolonged immobility, certain medical conditions, and the use of hormonal contraceptives or hormone replacement therapy can all increase the risk of developing Venous Thromboembolism (VTE).
• Symptoms of VTE


  Symptoms of Venous Thromboembolism (VTE) can include swelling, pain, warmth, and redness in the affected leg (DVT), as well as shortness of breath, chest pain, rapid heartbeat, and coughing up blood (PE).
• Diagnosis of VTE


  Venous Thromboembolism (VTE) can be diagnosed through a combination of physical exam, medical history, and imaging tests such as ultrasound, CT scan, or MRI.
• Prevention of VTE


  Staying active, maintaining a healthy weight, avoiding smoking, following a healthy diet, and taking precautions during travel can all help to reduce the risk of developing Venous Thromboembolism (VTE).
• Incidence of VTE


  An estimated 1-2 cases per 1,000 people in the general population each year. However, the incidence increases with age, with up to 1 in 100 people affected over the age of 80.
• D-dimer test


  A blood test that measures the level of a protein fragment called D-dimer, which is released when a blood clot dissolves. High levels of D-dimer may indicate the presence of a clot.
• Ventilation/perfusion (V/Q) scan


  A type of lung scan that can help to diagnose Pulmonary Embolism (PE) by comparing the distribution of air and blood flow in the lungs.
• Inferior vena cava (IVC) filter


  A small device that is inserted into the inferior vena cava (the large vein that carries blood from the lower body to the heart) to prevent blood clots from traveling to the lungs.