Week 10 - Venous Thromboembolism (VTE) Flashcards
What is VTE
A blood clot in vein of legs
- can lead to pulmonary embolism (clot in artery in lungs)
- Predominantly a disease of old age, seen in younger people ONLY if they have clotting abnormalities
- Incidence ↑ with age + ↑ in women during childbearing years
How does VTE develop
- Venous trauma
- damage to endothelium of vein leads to platelet activation + coagulation factors = thrombus forms - Venous stasis
- when hospitalised = immobile
- ↓ muscle contraction in vein = blood isn’t pumped through vein to heart
= blood pools + clots behind valves (cause endothelial damage + thrombi formed) - Hypercoagulability
- mutation in coagulation factors can ↑ risk of VTE
- imbalance in coagulation factors = ↑ clot or bleeding
What are Intrinsic (continuing) and Temporary risk factors for VTE
Intrinsic:
- Venous statsis (obesity)
- Cancer (damages cell causing hypercoagulability)
- Age > 60 (risk doubles every decade after 40)
- Heart failure
- History of DVT
- Smoking (affects blood flow + ↑ no. of platelets)
Temporary:
- Recent hospitalisation (immobile = stagnant blood in veins)
- Pregnancy + postpartum period
- blood clots easily so you lose less blood
- Recent major surgery
- Recent trauma
- Prolonged travel (>4 hrs)
How can VTE be prevented in hospitalised patients
(Mechanical Methods)
Applying pressure to leg to help blood return to heart
- ↓ pooling of blood = no clot formation
- prevents damage to vein
- ↑ venous blood flow
- can be used ALONE (when CAN’T use pharmacological methods i.e. active bleeding OR in COMBINATION)
- Anti-embolism stockings
- apply stocking to whole leg
- Intermittent pneumatic compressions (IPC)
- have cuff around leg which inflates + deflates (mimics muscle contraction)
- promotes blood return to heart
How can VTE be prevented in hospitalised patients
(Pharmacological Methods)
- LMW Heparin
- inhibits factor 10a - Unfractionated heparin
- inhibits factor 10a + 2a (thrombin) - Apixiban or Rivaroxiban
- inhibit factor 10a - Dabigatran
- direct thrombin inhibitor (factor 2a)
All drugs prevent thrombi formation
- fibrinogen conversion is inhibited = no mesh formed
What are the 3 VTE complications
- Reoccurrence
- ↑ risk within first 6-12 months
- 30% have reoccurrence within 10 years - PTS (Post-thrombotic Syndrome)
- causes chronic venous hypertension
- affects 50% of patients - Pulmonary hypertension
- due to pulmonary embolism
How does the risk assessment process work in hospitals
Assess risk of bleeding + thrombosis
- needs to be done for majority of patients admitted to hospital
- assess patients mobility level (if have ↓ mobility continue risk assessment)
- asses patient’s thrombosis risk (ticking what applies + initiating thromboprophylaxis)
- assess patient’s bleeding risk (tick what applies)
What role do different healthcare professionals have in preventing VTE
- Doctors
- conduct risk assessment (mobility, risk of thrombi + bleeding) - Nurses
- discuss VTE risks with patients
- administer mechanical or pharmacological treatment (thromboprophylaxis) - Pharmacists
- ensure thromboprophylaxis is prescribed correctly
- educate patients on importance of adherence - Midwives
- risk assess women for VTE
- educate women on how to administer pharmacological medication - Health visitors
- remind postnatal women of their risk of VTE
- look for signs / symptoms of VTE in women
- educate them on adherence + what signs to look for
What are the VTE NICE Guidelines - 2 Level DVT Wells Score
Score ≥ 2 = DVT likely
Score ≤1 = DVT unlikely
For people who are likely to have DVT:
Offer a proximal leg vein ultrasound scan + results within 4 hours if possible, if not possible offer:
- A D-dimer test, then
- Start therapeutic anticoagulation (choose anticoagulant that can be continued if DVT is confirmed e.g. Apixiban) AND
- A proximal leg vein ultrasound scan with the results available within 24 hours
