DVT & PE Flashcards
What is a PE?
Thromboemboli detach and travel through the right side of the heart to block vessels in the lungs
What cause haemodynamic collapse in PE?
right ventricle outflow doesn’t get round to left heart
What is a DVT?
Formation of thrombi within the lumen of the vessels that make up the deep venous system: venous valve pockets and other sites of presumed stasis
Describe an arterial clot?
Platelet rich clot
Why is venous clot fibrin rich?
in venous disease the bloodlfow is static and the coagulation cascade forms a fibrin rich clot
What percentage of cancer patients will have clot in their life?
20%
What are the three components of virchow’s triad?
Hypercoagulable state
Circulatory Stasis
Endothelial injury
What can contribute to hypercoagulable state?
Malignancy Pregnancy and permpartum period Oestrogen therapy IBD Sepsis Thrombophilia
What contributes to endothelial injury?
Venous disorders Venous valvular damage Trauma Surgery Indwelling catheters
What contributes to circulatory stasis?
Left ventricular dysfunction Immobility Paralysis Venous insufficiency or varicose veins Venous obstruction from tumour, obesity or pregnancy
Name some risk factors of clot?
Smoking Travel Prothrombin gene mutation Combined oral contraception Hormone replacement Protein C deficiency Protein S deficiency Factor V leiden mutation Pregnancy Active malignancy Day surgery Major surgery
What is a provoked VTE?
o transient reversible factors: surgery or hospitalisation
o continuing irreversible factors: cancer
What is an uprovoked VTE?
o unprovoked idiopathic: VTE
What type of VTE is likely to re-occur?
Unprovoked VTE; more likely to have reoccurrence than provoked over 10 yrs
What are the consequences of VTE?
- fatal PE
- risk of recurrent VTE
- post thrombotic syndrome (PTS)
- chronic thromboembolic pulmonary hypertension (CTEPH)
- reduced quality of life
What is PTS?
post thrombotic syndrome (PTS)
o characterised by pain: much more significant than what you can see
o clear brown discolouration- pooling blood
o venous ulceration
o oedema
o eczema
o varicose collateral veins
What is the treatment for PTS?
o compression stockings are pretty much the only limited treatment
What is CTEPH?
chronic thromboembolic pulmonary hypertension
o serious complication of PE
o relatively rare
o unexplained progressive breathlessness and hypoxia
o right heart failure
o mortality rates are 4-20%
What investigations can be done if VTE is suspected?
Pre-test probability scores
D-dimer
Ultrasound
What are the different types of ultrasound?
compressibility- put pressure on vein- if they can compress the femoral it suggests the pressure is not high above it and there is no more proximal clotting
Doppler- shows any turbulent flow
What is the significance of d-dimer in VTE?
- Low positive predictive value for VTE
- Valuable first line screening test for suspected VTE with low Wells score
- 25-50% patients require no further investigations
What are the other scoring systems for VTE probability?
Wells Score
Geneva Score
What imaging techniques can be used in VTE?
CXR
-Usually normal in PE. Can show pleural effusions and occasionally infarct
V/Q scan
- Ventilation/Perfusion imaging. Demonstrates mismatched perfusion defects. Still a useful test particularly in small peripheral PEs and pregnancy (perfusion only)
- have to have a normal CXR for it to be useful
- Limited by frequency of inconclusive results, hence
CTPA has become gold standard
How can we treat DVT and PE?
Pharmacological interventions
Mechanical interventions
recommended
Screening
What are the pharmacological interventions for DVT and PE?
- Anticoagulation
- Thrombolysis
- Analgesia
What are the mechanical interventions for DVT and PE?
- Graduated compression stockings
- IVC filters
What are the screenings recommended in DVT and PE?
-Thrombophilia
advices against screening in DVT
Cancer
Why is warfarin so dangerous?
-no antidote;
oreverse effects with Vitamin K and Fresh frozen plasma
What is the recommended medication for preventing recurrent DVT and PE in adults
- Apixaban
- Rivaroxiban
What do you do after a period of time on anticoagulants?
- Continuing anticoagulants prevents further events
- Apixaban has the same rate of major bleeding as a placebo: making it a very safe anticoagulant
- rivaroxaban has roughly the same bleeding rate as aspirin
- all men who have unprovoked VTE or irreversible provoking factors should continue on longterm coagulation
- women have a lower recurrence rate than men but will also benefit
Why is drug associated DVT and PE significant?
- almost all IV drug users will develop a VTE at some point
- risk of haemorrhage/death vs. embolic disease
What is the recommended medication for drug associated DVT or PE?
-rivaroxaban or fragmin
What medication is sugested in cancer related DVT or PE?
- evidence base favours weight adjusted fragmin
- safety benefit with fragmin
What is significant about phlegmasia?
- arterial compromise secondary to extensive DVT
- high pressure in venous system it affects arterial flow causing a rapid ischaemic leg
- often results in death
What does phlegmasia require?
Quick thrombolysis
Who should be considered for thrombolysis in DVT?
patients with symptomatic ileofemoral DVT symptoms less than 14 days duration and;
- good functional status
- a life expectancy of 1 year or more
- a low risk of bleeding
Who should be considered for thrombolysis with PE?
-Consider pharmacological systemic thrombolytic therapy for patients with PE and haemodynamic instability
Which PE patients should not be considered for thrombolysis? Why?
patients with PE and haemodynamic stability
no data to suggest it’s that effective, unless haemodynamic collapse is present
What is the compression stocking used for?
To prevent PTS
When should compression stockings be worn?
as soon as possible after diagnosis (one week after diagnosis or when swelling is reduced sufficiently and there are no contraindications)
- NB NICE QS29 states below-knee graduated compression stockings should be offered within 3 weeks of diagnosis
- To be worn for at least 2 years post thrombosis
- Stocking need only be worn on affected leg or legs
What are the contraindications for compression stockings?
Arterial disease
What is an IVC filter?
-sits in IVC designed to catch any big clots; preventing death by PE
What does NICE recommend for IVCs?
-Offer temporary IVC filters to patients with proximal DVT or PE who cannot have anticoagulation treatment
^this is a really bad idea, if people cannot be anticoagulated doing a procedure like this is just going to make them clot
-Consider IVC filter for patients with recurrent proximal DVT or PE despite adequate anticoagulation only after considering increasing target INR or LMWH
What is the opinion on IVCs in dundee?
- IVC filters often = complications
- they thrombose. Ideally not a replacement for anticoagulation
