Use of Inferior Vena Cava (IVC) Filters (bsh 2006)
Potential Indications
To prevent PE in patients with VTE who have a contraindication to anticoagulation (AC)
Selected patients who develop PE despite AC (Alt preferred, e.g. Higher INR target)
Pregnant patients with a contraindication to AC
Pregnant patients with a VTE <2 weeks prior to delivery
Pre-op patients with VTE <1 month ago in whom AC must be stopped
Prior to pulmonary endartectomy
Not an indication
Unselected patients with VTE who can have AC
Free floating thrombus
Thrombolysis
Filters
The only purpose is to prevent PE, & actually increases risk of DVT.
Complications
Immediate: Misplacement, pneumothorax, haematoma, air embolus, arteriovenous fistula
Early: Insertion site thrombus (8.5%), infection
Late: DVT (21%), IVC thrombus (2-10%), post-thrombotic syndrome, filter migration
Relevant Trials
Note that the BSH guidance is from 2006!
400 patients. Permanent IVC filter to prevent PE in patients with a proximal DVT
Primary end point: New radiological PE at 12 days. 1.1% filter vs 4.8% no filter.
BUT not statis. significant, study under recruited/under powered (original target 800), missing data
2-yr follow-up: Increased risk of DVT recurrence in filter group (20.8% vs 11.6% if no filter)
No effect of immediate or long-term mortality.
Retrievable IVC filter, effect on risk of recurrent PE in patients who also receive anticoagulation
Primary end point: Symptomatic recurrent PE at 3 months (3% vs 1.5%, not statistically significant)
Note also substantial number of filters could not be retrieved
Conclusion: Retrievable IVC filters do not reduce risk of symptomatic recurrent PE in anticoagulated patients.
Association between IVC filters for VTE and 30-day mortality rates, in patients who did not receive anticoag.
US insurance registry study, 126,000 patients. Not randomised, Availability bias, Immortal time bias.
Noting study limitations, results suggest increase 30-day mortality associated with use of IVC filters.
Where do things stand now with IVC Filters?
In the absence of evidence, practice varies nationally
Local practice at my hospital sees very little role for IVC filters.
The exception? The patient who truly cannot be anti-coagulated, e.g. in setting of life-threatening bleeding
Even then, a RCT is needed to know if filters cause more harm than good? (Insertion complication rate is approx 20%)
The case-by-case exceptions? The patients requiring unavoidable surgery shortly after proximal DVT, particularly if less than 14 days since the start of anticoagulation.
Make sure to know your local practice, and the rationale for it.