Venous thromboembolic disease Flashcards
What is a DVT?
Formation of a thrombi within the lumen of the vessels that make up the deep venous system
Where are DVTs commonly formed?
Venous valve pockets and other sites of stasis
Are DVTs platelet or fibrin rich clots?
FIbrin rich
WHat is a distal vein thrombosis?
DVT of the calves below the poptiteal vein
What is a proximal vein thrombosis?
DVT of the popliteal or femoral vein
Do distal DVTs require treatment?
No but proximal ones do
What ercentage of those with a proximal DVT develop post thrmbotic syndrome?
30%
What are the largest risk factors for DVT?
1) Major surgery
2) Day surgery
3) Active malignancy
4) Pregnancy
5) Thrombophilia
What is virchows triad and which conditions contribute to it?
Hypercoaguable state
Malignancy, pregnancy, oestrogen therapy, IBD, sepsis, thrombophilia
Turbulence/stasis
left ventricular dysfunction, immobility, paralysis, venous insufficiency/varicose veins, venous obstruction (tumour, pregnancy, obesity)
Endothilial injury
Venous disorders, venous vascular damage, trauma, surgery, indwelling catheters, PWID
What is a provoked DVT?
Transient risk factor- surgery or hospitalisation
Continuing risk factor- cancer, obesity, thrombophilia
What is an unprovoked DVT?
No identifiable cause
What type of DVT has the highest rate of recurrence?
unprovoked DVT
What are the consequences of venous thromboembolism?
Fatal PE Increased risk of recurrent VTE Post thrmbotic syndrome Chronic thromboembollic pulmonary hypertension CTEPH Decreased QoL
What is post thrombotic syndrome?
Pain: severe, nerve like, effects daily activities
Oedema
Hyperpigmentation: browning of skin- blood pooling and blood entering the skin
Eczema
Varicose collateral veins
Vein ulceration
What is the treatment for post thrombotic syndrome?
Limited
Compression stockings but cannot be used in peripheral arterial disease
What is CTEPH?
Chronic thromboembolic pulmonary hypertension
serious complication of PE occurring in 5% of patients
WHat are the symptoms of CTEPH?
initially assymptomatic then progressive dyspnoea and hypoxia
Right sided heart failure- cor pulmonale
Progressive condition withmortality of 4-20%
How is CTEPH treated?
Pulmonary endartectomy
What are the investigations for DVT?
Pretest probability scores- Wells score
D-dimer- product of the breakdown of fibrin. High negative predictive value
How is the Wells score for DVT used?
low score- do d dimer
High score- need imaging regardless of D dimer
What are the pretest probability scores for PE?
Modified wells score. Score <4 makes PE unlikely. Score >4 makes PE likely Geneva score for PE. Score 0-3 = low risk => do d dimer Score 4-10 = intermediate risk +. do d dimer and imaging? Score >10 = high risk => Imaging
How do you image DVT?
Compresability U/S- can you fully compress the vein
Dopler U/S- visualise veins and flow direction with colour to show turbulence/stasis.
How do you image fore PE?
V/Q scanning used to show mismatched ventilation perfusion defects. Useful in small PEs and pregnancy. Limited by inconclusive results and skilled people
CXR- normally normal acutely but may show a wedged shaped infarct later
CT pulmonary angiography is the gold standard test
What are the pharmacological treatments for VTE?
Anticoagulation, thrombolysis and analgesia
