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
A 43-year-old lady presents with central chest pain, worse on deep inspiration, and shortness of breath. After her history and examining her, you suspect a pulmonary embolus (PE). Her Wells’ score is 9. You plan to do a CTPA, but the radiologists request you order one further investigation prior to a CTPA. What investigation is this likely to be?
Chest X-ray
A 24-year-old air stewardess presents to the emergency department complaining of pleuritic chest pain and shortness of breath, after arriving to London from Bangkok. On examination she has a swollen left calf, with tenderness over the deep venous system. Her observations are as follows: heart rate 101 bpm, blood pressure 108/73 mmHg, sats 94% on room air and temperature 37.5ºC. Chest xray is unremarkable.
You request a CTPA as you are concerned about a pulmonary embolus. The radiologist agrees but states it will be about 90 minutes until the scan can happen. What should you do next?
Give treatment dose tinzaparin whilst waiting for the scan –> well’s score is >4
