Venous Thromboembolism Flashcards
How do DVTs form?
backwash of blood and pooling of blood as veins are distended don’t function as well as before
How many deaths are caused by VTE per year?
25,000
10% of hospital death
What is a thrombus?
blood clot within the body
What is an embolus?
Some material which is transported in the blood stream and lodges in a blood vessel at a different site.
What is virchow’s triad?
Immobile (stasis of blood flow), endothelial injury, hypercoaguability
What are the clinical consequences of thrombus formation?
DVT, PE, MI, Stroke, DIC
Who’s at risk of VTE?
Surgical patients, post-op with bed rest, anaesthesia, medical patient
How is VTE prevented (3)?
Risk assessment for each patient
Mechanical - Anti-embolism stockings, Intermittent pneumatic compression sleeves (IPC)
Pharmacological - LWMH SC, UFH IV or DOACs oral
When are anti-embolism stockings contraindicated in?
pre-exisiting arterial insufficiency, cardiac failure, peripheral neuropathy
How is Acute VTE managed?
Well Score, Heparin (LWMH or UFH), oral warfarin. Heparin stopped after 48 to 72 hrs once warfarin has reached therapeutic range.
How can a DVT present?
local pain, oedema, swollen, warm leg, calf circumference greater than 3 cm compared with unaffected leg.
How is DVT diagnosed?
USS, D-dimer test
Moderate or high (‘likely’) probability of DVT or with elevated D-dimer levels, objective diagnosis of DVT should be obtained using appropriate imaging.
How long should a patient be on warfarin for?
3 months then assess risk and benefit of continuing
What is pulmonary embolism?
blockage in the pulmonary artery, the blood vessel that carries blood from the heart to the lungs.
What are the symptoms of PE?
pleuritic chest pain, SoB, haemoptysis, dizziness, syncope
What are the signs of PE?
increased RR, tachyarrythmia, signs of a DVT, low-grade temperature
What ECG changes may be seen in PE?
S1 Q3 T3
S wave lead 1, Q wave lead 3, T wave inversion lead 3
What might be seen on ABGs in PE?
Hypoxia or type 1 resp failure
How is PE diagnosed?
CT pulmonary angiography
How long should patient with active cancer be on LWMH for?
6 months then reassess
How long should a patient be on warfarin for unprovoked PE?
longer than 3 months
Which medications cause increased risk of VTE?
OCP, HRT, raloxifene and tamoxifen, anti-psychotics (olanzapine)
What are general risk factors for VTE?
increasing age, obesity, FH, pregnancy, immobility, hospitalisation, anaesthesia
What imaging is used for suspected PE in patients with renal impairment?
Ventilation/perfusion scan
