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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–
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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
•
• Spinal cord trauma
• High risk polytrauma
IVC filter - prophylactic indications
• surgery / delivery in patients with DVT or recent PE
•
• 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
•
•
•
•
1 RCT patients with DVT
Combined with trial of LMWH and iv heparin
200 pts anticoagulation
200 pts anticoagulation + filter
•
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
•
•
•
•
1 RCT patients with DVT
Combined with trial of LMWH and iv heparin
200 pts anticoagulation
200 pts anticoagulation + filter
•
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
•
•
•
•
1 RCT patients with DVT
Combined with trial of LMWH and iv heparin
200 pts anticoagulation
200 pts anticoagulation + filter
•
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