Risk Assessment for VTE
Which of the following best
describes you?
1. Physician
5
2. Haematologist
15
3. Surgeon
2
4. Nurse
28
5. Pharmacist
8
6. Health service manager /commissioner
6
7. Other
29
Which of the following best
describes your institution?
1. Teaching hospital
35
2. District general hospital
23
3. Primary care practice
0
4. Primary care management (PCT)
1
5. Private hospital
4
6. Other
10
Do surgical patients in your hospital receive
thromboprophylaxis?
1. Regularly
59
2. Occasionally
5
3. Rarely
1
4. Never
0
Do medical patients receive
thromboprophylaxis in your hospital?
1. Regularly
34
2. Occasionally
24
3. Rarely
6
4. Never
2
Which risk-assessment tool does
your hospital use?
1. Surgical-specific only
10
2. Medical-specific only
1
3. Medical- and surgical-specific
39
4. Unified
4
5. CMO tool published in September 2008
0
6. None
4
7. Don’t know
4
If used, is the risk-assessment
tool:
1. Opt in (must fulfil specific criteria in order
to be prescribed prophylaxis)?
39
2. Opt out (all given chemical prophylaxis unless
contraindicated)?
15
3. Other
3
Which of the following are used for
thromboprophylaxis in your hospital?
1. Anti-embolism stockings
0
2. Intermittent pneumatic compression
0
3. Low molecular weight heparin
1
4. Unfractionated heparin
0
5. Warfarin
0
6. Aspirin
0
7. Fondaparinux
0
8. New oral agent
0
Does your hospital provide extendedduration thromboprophylaxis?
1. Routinely
19
2. Occasionally
33
3. Rarely
4
4. Never
6
Risk assessment for VTE
• Risk
• Risk assessment
• Thromboprophylaxis risk assessment
strategies
Risk assessment for VTE
• Risk
• Risk assessment
• Thromboprophylaxis risk assessment
strategies
What is risk?
Risk can be defined as the probability of an
unwanted event occurring and the severity of
potential loss
Risks exist because things considered to
have value are placed at risk
Risk assessment for VTE
• Risk
• Risk assessment
• Thromboprophylaxis risk assessment
strategies
What is Risk Assessment?
• Risk assessment consists of an objective
evaluation of risk in which assumptions and
uncertainties are clearly considered and
presented.
• Part of the difficulty of risk management is
that the measurement of the quantities in
which risk assessment is concerned potential loss and probability of occurrence
- can be very difficult to measure.
Wikipedia
Risk Assessment for VTE
• Potential losses:
– Morbidity or mortality from VTE
(including complications of therapy)
– Financial cost of investigating and
treating VTE
– Increased future risk of VTE
• Probability of occurrence:
– Likelihood of patient developing VTE
Potential Losses from VTE
•
Morbidity
– Post thrombotic syndrome in 30%, severe in 3-5%1
– Chronic thromboembolic pulmonary hypertension in 4-8% of patients
following PE2
– Bleeding from anticoagulant therapies (1% major bleeding)
•
Mortality
–
–
–
–
•
25,000 patients each year are thought to die of VTE in UK hospitals
Mortality from DVT 1-6%
Mortality from PE 10-30
Mortality from anticoagulant therapies (0.3%/year)
Costs to healthcare system
– Investigation and treatment of thrombotic episode
– Prolongation of inpatient stay
– Treatment of long term complications
1 Khan SR et al. Ann Int Med 2008
2 Dentali F et al. Thr Res Feb 2009
Probability of occurrence of VTE in
hospitalised patients
From ACCP Guidelines on prevention VTE Chest 2008
Most VTE cases are not detected
20%
symptomatic
80%
asymptomatic
Likelihood of symptomatic VTE
in hospitalised patients
10
9
8
7
6
proximal DVT
5
clinical PE
4
fatal PE
3
2
1
0
medical
low
moderate
high
very high
Risk Factors for VTE
Patient
characteristics
Disease related
Age
Obesity
Varicose veins
Immobility
Pregnancy
Thrombophilia
Hormone therapy
Previous VTE
Surgical therapy
Trauma
Cancer/ cancer therapies
Cardiac/respiratory failure
Myocardial infarction
Paralysis of lower limb(s)
Infection
Inflammatory bowel disease
Nephrotic syndrome
Polycythaemia
Proportion of hospital
inpatients at risk of VTE
Endorse study Lancet 2008
Thromboprophylaxis strategies
are required
• It is, as yet, impossible to identify those
individuals who will develop VTE
• Screening using imaging techniques is
of low sensitivity, expensive, time
consuming
• Asymptomatic DVT can cause fatal PE
Potential losses: risk of
intervention
• Adverse effects of prophylactic therapies
– Bleeding
• Dependent on surgical procedure
• Intracerebral haemorrhage/ GI bleeding
– Heparin Induced Thrombocytopenia
• Dependent on prophylactic agent chosen
• Higher with unfractionated heparin
• Costs to healthcare system of adverse
events
Risk assessment for VTE
• Risk
• Risk assessment
• Thromboprophylaxis risk assessment
strategies
Why Risk Assessment for VTE?
Identify patients at
significant risk of
VTE
Objectives of RAM
Simplify decision
making
Improve the use of
appropriate
thromboprophylaxis
Cost containment
Reduce the burden of VTE
Cohen AT et al. J Thromb Haemost 2003;1 (Suppl 1):OC437
Thromboprophylaxis Risk
Assessment Strategies
• Opt-in
– Surgical only
– Medical only
– Hybrid models
• Opt-out
• Electronic risk assessment (opt in or opt
out)
Autar risk assessment
Sheffield surgical risk
assessment
Hunt BJH March 2009
Hunt BJH March 2009
Opt-out model
• Little evidence base
• Advantages
– Patients at risk of VTE possibly more likely to
receive thromboprophylaxis
• Disadvantages
– Patients not at risk will receive prophylaxis
– Patients are likely to be given prophylaxis even
if at increased risk of side-effects
Information Technology helps
Kucher, N. et al. N Engl J Med 2005;352:969-977
Endorse study Lancet 2008
Amended ACCP guidance
Level of
risk
Approximate DVT
risk without
prophylaxis
Suggested
thromboprophylaxis
Low
Minor surgery in mobile
patient
Medical patients who are
fully mobile
<10%
None
Early ambulation
Moderate
Most general, open gynae or
urologic surgery
Medical patients bed rest or
sick
10-40%
LMWH
LDUH
Fondaparinux
High
THA, TKA, hip fracture,
major trauma, SCI
40-80%
LMWH,
fondaparinux, oral vit
K antagonist
• We recommend the use of strategies
shown to increase thromboprophylaxis
adherence, including the use of
computer decision support systems,
preprinted orders, and periodic audit
and feedback.
• Passive methods such as distribution of
educational materials or educational
meetings are not recommended as sole
strategies to increase adherence to
thromboprophylaxis
Geerts et al, ACCP, Chest 2008
Risk assessment for VTE
• Identify patients who would benefit from
thromboprophylaxis
• Strategy chosen will be dependent on
– Culture of organisation
– Local opinion
– Information Technology
• For strategy to work- needs to be simple
Rhona Maclean
Sheffield Teaching Hospitals
Consultant Haematologist
Rhona.maclean@sth.nhs.uk