Venous Thrombo-embolism Prevention Flashcards
(52 cards)
1
Q
What is a venous thromboembolism
A
- Blood clot that starts in the calf- they may remain localise or they may go across the vein to occlude it and grow proximally
- can embolism and move around and spread to other areas of the body
2
Q
What are the consequences of venous thromboembolism
A
- DVT
- PE
- Post thrombotic syndrome
- leg ulcers
3
Q
What is the 3rd most common cause of cardiovascular death
A
PE
4
Q
what is the second most common cause of death in cancer and commonest cause of preventable hospital related death and most common cause of maternal mortality
A
PE
5
Q
Why is VTE important
A
Common - 1 in 1000 per year
- treatments effective but significant risks - major and fatal bleeding
6
Q
If you get a VTE what are you at risk of in the future
A
- Post thrombotic syndrome
- Chronic thromboembolic pulmonary hypertension (CTEPH)
7
Q
What are most death from PE due to
A
- diagnostic failure rather than treatment failure - most patients die as the diagnosis is not suspected
8
Q
What is your chances of dying from a DVT and PE
A
VTE – natural history
30-day case fatality PE vs DVT
– 7%v2%(OR3.8, 95% CI 1.6-9.2)
– ≈ 50% of above deaths from PE (approx. 4% v 1%)
9
Q
What is pulmonary embolism the most common cause of
A
- Most common cause of missed or delayed diagnosis
10
Q
After you stop anticoagulants after 3 months what is the risk of developing another VTE
A
- Overall 5% per year initially
• 20% at 5 years
• 30% at 10 years
– Higher (≈10% in first year) if unprovoked than if provoked by temporary risk factor
11
Q
What is post thrombotic sydnrome
A
- complicates 40% of DVT cases
- develops within 2 years of DVT diagnosis
- variable severity
- reduced quality of life
- cost to individual and society
12
Q
What are the symptoms of post-thrombotic syndrome
A
- pain
- swelling
- skin induration/discolouration
- ulceration
13
Q
what 3 risk factors lead to VTE/PE development
- virchows triad
A
- blood flow
- blood coagulability
- vessel wall damage
14
Q
What are the major risk factors for VTE
A
- Fracture of hip/pelvis
- Hip or knee replacement surgery
- Major general surgery especially for malignancy
- Major trauma
- Spinal cord injury
- Hospitalisation with acute medical illness
15
Q
What are the moderate risk factors for VTE
A
• Previous VTE • Malignancy/chemotherapy • Pregnancy and post-partum period • Combined oc pill or hormone therapy • Central venous line • Thrombophilia Risk factors • Other medical conditions e.g. nephrotic syndome, inflammatory bowel disease, Behçets syndrome
16
Q
What are weak but common risk factors for VTE
A
- Age
- Travel-related thrombosis
- Obesity
- Varicose veins
- Diet
- Smoking
- Air pollution
17
Q
describe how hospital admission leads to VTE risk
A
VTE following hospital discharge Worcester DVT study (2007) • 74% presented as outpatients – 37% recent hospitalisation +/- surgery – 23% recent major surgery +/- hospitalisation – 29% recent cancer diagnosis – 20% previous VTE diagnosis – 70% ≥1 VTE risk factors
18
Q
why do cancer patients have an increased risk of VTE
A
– Cancer is prothrombotic
– Immobility
– Chemotherapy
– Central venous lines
19
Q
of patients presenting with unprovoked VTE…
A
5% have a new cancer diagnosed within 3 years
20
Q
What is the 2nd leading cause of death in cancer patients
A
VTE
21
Q
When you are pregnant what increases your risk of developing a VTE
A
- Obesity
- Maternal age > 35 years
- Caesarean section (especially emergency)
22
Q
What is trousseau syndrome
A
- the connection between VTE and cancer
23
Q
Describe how the risk of VTE change in pregnancy
A
- mostly level during pregnancy but increases before delivery
- after delivery it massively increases in the first 6 weeks after delivery
24
Q
What are the NICE guidelines for VTE
A
- All patients on admission receive an assessment of VTE and bleeding risk using the clinical risk assessment criteria
- patients are offered verbal and written information on VTE prevention as part of the admission process
- patients provided with anti-embolism stockings have them fitted and monitored
- patients are re-assessed within 24 hours of admission for risk of VTE and bleeding
- patients assessed to be at risk of VTE are offered VTE prophylaxis in accordance with NCIE guidelines
- patients are offered verbal and written information on VTE prevention as part of the discharge process
- patients are offered extended VTE prophylaxis
25
Name thrombosis risk
- Active cancer or cancer treatment
- age over 60
- dehydration
- known thrombophiliais
- obesity
- one or more significant medical co-morbidities - e.g. heart disease, metabolic, endocrine or respiratory pathologies, acute infectious diseases
- personal history or first degree relative with a history of VTE
- use of hormone replacement therapy
- use of oestrogen containing contraceptive therapy
- varicose veins with phlebitis
- pregnancy or less than 6 weeks post partum
admission related
- significantly reduced mobility for 3 days or more
- hip or knee replacemetn
- hip fracture
- total anaesthetic and surgical times greater than 90 minutes
- surgery involving pelvis or lower limb with a total anaesthetic and surgical time greater than 60 minutes
- acute surgical admission with inflammatory or intra-abdominal condition
- critical care admission
- surgery with significant reduction in mobility
26
Name the bleeding risks
Patient related
- active bleeding
- acquired bleeding disorders
- concurrent use of anticoagulatns known to increase the risk of bleeding
- acute stroke
- thrombocytopaenia
- uncontrolled systolic hypertension - 230/120 or higher
- untreated inherited bleeding disorder
Admission related
- neurosurgery, spinal surgery or eye surgery
- other procedure with high bleeding risk
- lumbar puncture/epidural/spinal anaesthesia expected within the next 12 hours
- lumbar puncture/epidural/spinal anaesthesia within the previous 4 hours
27
Name the mechanical methods of thromboprophylaxis
- Anti embolism stockings
| - intermittent pneumatic compression
28
Name the pharmacological methods of thromboprophyalxis
– Unfractionated heparin
– Low molecular weight heparin
– Fondaparinux
– New direct oral anticoagulants (DOACs)
29
describe parenteral thromboprophylaxis
– Unfractionated heparin 5000 u sc bd or tds
– Low molecular weight heparin
• Enoxaparin 40 mg sc od
• Dalteparin 5000 u sc od
• Tinzaparin 4500 u sc od
– Fondaparinux - synthetic pentasaccharide - 2.5 mg sc od
30
describe oral thromboprophylaxis
– Direct thrombin inhibitor
• Dabigatran
– Factor Xa inhibitor
• Rivaroxaban
• Apixaban
• Edoxaban (not yet licensed for VTE prevention)
31
How does heparin work
- binds to naturally ocucring anti thrombin III
- and this speeds up the inhibition of the activated clotting factors
- particulary factor IIa and Xa
32
How does LMWH work
- shorter chains
| - inhibits factor Xa but some are not long enough to inhibit thrombin therefore you only get some thrombin inhibition
33
How does fondaparinux work
- inhibition of Xa and no inhibition of thrombin
34
What does dabigatran inhibit
thrombin
35
What does apixaban, edoxaban, rivaroxaban inhibit
Factor Xa
36
When do you get a peak of DOACs
around 2 hours later
37
What is the half life of DOACs
12 hours
38
Where are the DOACs eliminated
- dabigatran - renal
| - others not the renal
39
What patients should not recieve graduated compression stockings
- Known peripheral vascular disease
- Leg or buttock pain on exercise
- Previous or planned revascularisation surgery
- Massive leg oedema where stockings are unable to be fitted
- Leg conditions in which stockings would interfere eg dermatitis, recent skin graft, gangrene
40
What is the standard approach to VTE
• Anticoagulant therapy
– Prevent extension and recurrence (not thrombolytic)
Standard approach
• Immediate therapy with treatment-dose heparin (LMWH)
• Overlap with warfarin until INR in therapeutic range (5 days minimum)
• Then stop LMWH, continue warfarin for 3 months (monitor in anticoagulant clinic) and review duration
41
What does warfarin inhibit
Vitamin K antagonists
| • Factors II, VII, IX, and X (and protein C and protein S)
42
What is the half life of warfarin
36 hours
43
Where is warfarin metabolised
in the liver
44
What are the side effects warfarin
– Risk of major bleeding – 1-2% per year
– Avoid in pregnancy – teratogenic and bleeding
– Safe for breast feeding
45
How do you monitor warfarin
- INR (derived from the prothrombin time - extrinsic and common pathway)
46
What DOACs require a heparin lead in
Dabigatran and Edoxaban
| - heparin lead in required 5-10 days
47
describe an updated VTE plan
Acute (5-10 days)
- IV heparin, LMWH, Fondaparinux, DOCA
Short term (3-6 months )
- warfarin
- LMWH
- DOAC
long term (beyond 3-6 months)
- Warfarin
- LMWH
- DOAC
- ASA
- nothing
48
How long should you have warfarin in a provoked v an unprovoked VTE
Venous thromoboembolism = length of warfarin treatment
- provoked (e.g. recent surgery): 3 months
- unprovoked: 6 months
49
What can D dimer be elevated in
- DVT
- pregnancy
- cancer
- hospitalised
- elderly patients
50
What test do you do after a D dimer is positive
- do a CT pulmonary angiography
51
What advice is given to people on warfarin
- Shouldn't take it if pregnant
- can take it whilst breastfeeding
- avoid cranberry juice
- warfarin is also affected by alcohol
52
What is the general information that someone taking anticoagulants should be old
- avoid injuring yourself as it can make you prone to bleeding
- should not take aspirin, herbal remedies such as St John's Wart
- some medicines can effect anticoagulants such as antibiotics, antidepressants, corticosteroids, NSAIDs
