Transcript IVC filters what you need to know

IVC filters
what you need to know
Sam Chakraverty
Consultant Radiologist
Ninewells Hospital
Dundee, Scotland
IVC filters
When rather than How
IVC filters
• Placed to prevent
significant PE from
deep veins of the
leg, pelvis or IVC
• The best method of
preventing such PE
is anticoagulation
IVC filters
• RITI module 1c_027
• Clinical Radiology (2009) 64:502-509
– 3 centre audit in UK over 12 years
• BSIR IVC Registry
Venous thrombo-embolic
disease
• 30% of patients with venous TED die within 30 days
• 1 in 5 die of PE
• 1% hospital admissions from any cause
• 1 in 5 of these have PE
• Isolated calf vein thrombosis not always benign
Venous thrombo-embolic
disease
• Multiple controlled trials confirm benefit of
anticoagulation
• Repeated confirmation of efficacy for newer agents
• The best method of preventing such PE is anticoagulation
Evolution
• Prevention of possible embolism from deep veins to
lungs
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Surgical caval interruption
Surgical caval clips/plication
Insertion of filter with surgical access
Insertion of filter with percutaneous access
Possibility of retrieval
Most permanent filters retrievable
Indications
• Absolute / “definite”
• Relative
• Prophylactic
• Evidence base is poor
IVC filter – “definite” indications
• Recurrent PE despite adequate therapeutic
anticoagulation
• DVT or PE when anticoagulation is or has become
contraindicated
IVC filter - relative indications
• Patients with PE and limited cardiorespiratory reserve
• Patients with massive PE requiring thrombectomy or
thrombolysis
• “free-floating” iliofemoral DVT
IVC filter - prophylactic indications
• surgery / delivery in patients with DVT or recent PE
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• Spinal cord trauma
• High risk polytrauma
IVC filter - prophylactic indications
• surgery / delivery in patients with DVT or recent PE
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• Spinal cord trauma
• High risk polytrauma
• Evidence base = 0
IVC filter use variable
• USA
140 per 1 million
IVC filter use
• USA
140 per 1 million
• Sweden
3 per million
• UK ?
IVC filter use
• USA
140 per 1 million
• Sweden
3 per million
• UK ?
?30 per million
– But increasing x3 1996-2004
Evidence base is poor
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1 RCT patients with DVT
Combined with trial of LMWH and iv heparin
200 pts anticoagulation
200 pts anticoagulation + filter
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Day 12
– 2 patients had PE in filter group
– 9 patients had PE in non-filter group
– Odds ratio 0.22 (0.05- 0.9)
Evidence base is poor
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1 RCT patients with DVT
Combined with trial of LMWH and iv heparin
200 pts anticoagulation
200 pts anticoagulation + filter
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2 years
– 37 patients had recurrent DVT in filter group
– 21 patients had recurrent DVT in non-filter group
– Odds ratio 1.87 (1.1-3.3)
Evidence base is poor
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1 RCT patients with DVT
Combined with trial of LMWH and iv heparin
200 pts anticoagulation
200 pts anticoagulation + filter
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2 years
– 37 patients had recurrent DVT in filter group
– 21 patients had recurrent DVT in non-filter group
• NO difference in mortality
What does this tell us?
• IVC filters unlikely to stop all PE when
inserted in other groups of patients
• Associated with some increased
incidence of recurrent DVT
What does this not tell us?
• Whether any of our definite or absolute indications for
filter insertion are correct
• Whether our relative indications for filter insertion are
correct
Assumptions
• IVC filters don’t stop all
PE but hopefully stop
large life-threatening PE
• May therefore have
some impact on
mortality
• The increased risk of
recurrent DVT is
acceptable
Are parachutes effective?
multiple single airplane studies only
No RCT
Unlikely to get a RCT for filter
use in patients who are not
anticoagulated
Procedure
• Definite indications
– Reasonable to proceed
– Check patient has has the best, most cost-effective and
evidence-based treatment
• Relative indications
– Always discuss pros and cons
– No right answer
• Importance of audit and registry data over time
Procedure
• Usually aim to place below renal veins
• suprarenal placement if IVC thrombus
• small (6F) sheaths
• local anaesthetic
Procedure
• no sedation
• no starvation
• ? stay therapeutically anticoagulated
• bed rest 1 hour
Procedure
• Review imaging before you start
– Where is DVT?
– How big is IVC?
– May give you information re IVC anatomical variation
• Check you know how to deploy filter
– Some easier than others to remember
– Keep instructions to hand
Procedure
• Usually R CFV or R IJV
• Modern filters tolerant of other approaches
• Check anatomy normal (iliac vein confluence)
• Check position of renal veins
Procedure
• Mark site below renal veins
• Deploy filter
• Remove sheath
• Finish
Procedure – femoral approach
Procedure – jugular approach
Permanent or temporary?
• Place a potentially-retrievable filter anyway
• window for retrieval used to be 2 weeks, now longer
periods possible
• can remain as a permanent filter if becomes
appropriate
• anticoagulation if possible
Permanent or temporary?
• Decision and timing can be left until later, but don’t
lose patients
• Best is as early as possible e.g. mobilizing and
therapeutically anticoagulated ??
• Only 1/3 of retrievable filters end up being removed
Retrieval
• Potentially retrievable filters
not always retrievable
– IVC thrombus (doing its job)
• Or the cause...
– technical failure 5-10%
– Complication rate of removal
is not zero
– Do you need to retrieve it?
Retrieval
Complications
• Access site thrombosis
• IVC perforation
• Migration
– rare but catastrophic
• Structural failure
• IVC thrombosis
– ?10-20% at 5 years
– anticoagulate if possible
IVC filters
• Discuss non-definite indications
• The best method of preventing such
PE is anticoagulation