Medicine: VTE Flashcards
What’s proximal DVT?
DVT in popliteal vein or above
What’s Virchow’s Triad?
Virchow’s triad → three broad categories of factors that are thought to contribute to thrombosis
General risk factors associated with VTE
- increased risk with advancing age
- obesity
- family history of VTE
- pregnancy (especially puerperium)
- immobility
- hospitalisation
- anaesthesia
- central venous catheter: femoral >> subclavian
Underlying conditions that may predispose to VTE
Underlying conditions
- malignancy
- thrombophilia: e.g. Activated protein C resistance, protein C and S deficiency
- heart failure
- antiphospholipid syndrome
- Behcet’s
- polycythaemia
- nephrotic syndrome
- sickle cell disease
- paroxysmal nocturnal haemoglobinuria
- hyperviscosity syndrome
- homocystinuria
Medications that may put a person at risk of developing VTE
Medication
- combined oral contraceptive pill: 3rd generation more than 2nd generation
- hormone replacement therapy: the risk of VTE is higher in women taking oestrogen + progestogen preparations compared to those taking oestrogen only preparations
- raloxifene and tamoxifen
- antipsychotics (especially olanzapine)
Clinical presentation of DVT
- Pain
- Swelling
- Pitting oedema
- Tenderness
- Discolouration (redness)
- Heat
Clinical presentation of PE
- Shortness of breath
- Cough
- Chest pain (pleuritic)
- Tachycardia
- Hypotension
- Low-grade fever
- Haemoptysis
Complications of VTE
- Post-thrombotic syndrome (PTS) of the leg post DVT
- can occur within 1 - 2 years after DVT in 20% to 50% of all patients
- can lead to deep vein insufficiency and leg ulcers
- Death from PE
- Chronic thromboembolic pulmonary hypertension (CTPH)
- Secondary pulmonary hypertension can occur with right sided heart failure in the long-term post pulmonary emboli
- can occur after PE and is associated with
How to reduce risk of VTE in in-patient patients?
- All patients admitted to hospital should be individually assessed to identify risk factors for VTE development and bleeding risk
- For medical and surgical patients the recommended risk proforma is the department of healths VTE risk assessment tool
- BALANCE risk of bleeding vs VTE
General risk factors of VTE for the patients admitted
General risk factors:
- active cancer/chemotherapy
- aged over 60
- known blood clotting disorder (e.g. thrombophilia)
- BMI over 35
- dehydration
- one or more significant medical comorbidities (e.g. heart disease; metabolic/endocrine pathologies; respiratory disease; acute infectious disease and inflammatory conditions)
- critical care admission
- use of hormone replacement therapy (HRT)
- use of the combined oral contraceptive pill
- varicose veins
- pregnant or less than 6 weeks post-partum
Risk factors of VTE specific for medical and surgical patients
Medical patients:
- significant reduction in mobility for 3 days or more (or anticipated to have significantly reduced mobility)
Surgical/trauma patients:
- hip/knee replacement
- hip fracture
- general anaesthetic and a surgical duration of over 90 minutes
- surgery of the pelvis or lower limb with a general anaesthetic and a surgical duration of over 60 minutes
- acute surgical admission with an inflammatory/intra-abdominal condition
- surgery with a significant reduction in mobility
Patient-related risk factors for bleeding
What causes of patient’s admission would increase their risk of bleeding?
- neurosurgery
- spinal surgery
- eye surgery
- LP/epidural/spinal anaesthesia within next 12 hours or previous 4 hours
- other procedures with high bleeding risks
Types (2) of VTE prophylaxis
Types of VTE prophylaxis
Mechanical:
- Correctly fitted anti-embolism (aka compression) stockings (thigh or knee height)
- An Intermittent pneumatic compression device
Pharmacological:
- Fondaparinux sodium (SC injection)
- Low molecular weight heparin (LMWH) - e.g. enoxaparin (brand name = Clexane)
- Unfractionated heparin (UFH) - used in patients with chronic kidney disease
What medical anti-thrombotic prophylaxis can be used in a patient with CKD?
Unfractionated heparin (UFH)
How to reduce risk of VTE in hospital patient?
- Encourage patients to mobilise as soon as possible
- Do not allow patients to become dehydrated unless clinically indicated
- Consider VTE prophylaxis for people who are having antiplatelet agents for other conditions and whose risk of VTE outweighs their risk of bleeding
- Consider VTE prophylaxis for people at increased risk of VTE who are interrupting anticoagulant therapy
Advice re COCP/HRT pre-surgery
Advise women to stop taking their combined oral contraceptive pill/hormone replacement therapy 4 weeks before surgery
Examples of procedures where post- surgical prophylaxis is indicated
For certain surgical procedures (hip and knee replacements) pharmacological VTE prophylaxis is recommended for all patients to reduce the risk of a VTE developing post-surgery
Wells score components and results
Clinical probability simplified score
- DVT likely: 2 points or more
- DVT unlikely: 1 point or less