prophylactic use of ivc filters in trauma

1. Dr. Mubashar Hashmi
Critical Care Medicine
A Multicenter Trial of VenaCava Filters in
Severely Injured Patients
Original Article

2. History
• 1868 - Trousseau suggested placing a barrier in the IVC to prevent PE
arising from venous thrombi.
• 1893 - Bottini.
• 1960’s – Mobin-Uddin and original Greenfield filters
• 1998 – Decousus et al recognized an increase rate of lower extremity
DVT with permanent IVC filters.
• 2002 - Retrieval filters developed to reduce IVC filter complications.

3. TYPES OF FILTERS

6. RETRIEVABLE FILTERS

7. SIR guidelines for IVC Filter/DVT
• Documented VTE &
• Absolute contraindication
to anticoagulation
• Complication of
anticoagulation resulting
in cessation of therapy
• Failure of anticoagulation
Classic
Indications

8. Extended indications
Iliocaval DVT or large, free-floating proximal DVT
Difficulty establishing therapeutic anticoagulation
Massive PE treated with thrombolysis/thrombectomy
Chronic PE treated with thromboendarterectomy
Thrombolysis for iliocaval DVT
VTE with limited cardiopulmonary reserve
Recurrent PE with filter in place
Poor compliance with anticoagulation
High risk of complication of anticoagulation (e.g., risk for frequent falls)

9. Prophylactic indications
No evidence of VTE,
High Risk of developing DVT and/or PE- trauma / surgery/medical
Cannot receive anticoagulation or be monitored for the development of
VTE.
Retrospective case series - placement of prophylactic IVC filters in trauma
patients may reduce symptomatic and fatal PE.
However, currently no randomized trials to support the use of
prophylactic IVC filters
DESPITE THIS, PROPHYLACTIC INDICATIONS NOW ACCOUNT MORE
THAN HALF OF ALL FILTER PLACEMENTS.

10. contraindication
1. Absolute contraindication : Access into the IVC.
2. Relative contraindications include the following:
Deranged coagulation
Total thrombosis of the IVC
Bacteremia, sepsis, or both
Caval diameter less than 15 mm
 A consensus statement Neurocritical Care Society recommended against the
routine use of IVC filters for primary prophylaxis of venous thromboembolism in
adult patients with an external ventricular drain in place. [11]
 A guideline from the American College of Chest Physicians (ACCP) recommended
against the use of IVC filters in patients with acute DVT or PE who are receiving
anticoagulant therapy. [12]

11. COMPLICATIONS

12. IVC FILTERS
WHERE DO STAND
EXPERIENCE, RECOMMENDATIONS
& FINDINGS
LITERATURE REVIEW

13. 43 % not received prophylaxis in first 7 days
19 % developed VTE

14. Ann Surg.Oct 2015;262(4)
Prophylactic Inferior Vena Cava Filter
Placement Does Not Result in a Survival Benefit
for Trauma Patients.

16. IVC filters for prophylaxis and treatment of
VTE, a low retrieval rate and inconsistent use of
anticoagulant Therapy – SUBOPTIMAL OUTCOME due
to high rates of venous thromboembolism.
JAMA 2013 APRIL

17. Lack of benefit and actual harm when IVCF
are used for Prophylaxis.
IVCF are likely being over-utilized.
Retrieval rates are low and information regarding appropriate
use and surveillance are lacking.
Use of these devices should be limited to patients with acute
VTE who cannot receive anticoagulation

18. Recent trends suggest that a higher
proportion of patients receive temporary
IVCF, for predominantly relative indications.

19. Indications for IVC filters use

21. Predicting Safety And Effectivness Of Inferior vena
caval filters- (PRESERVE TRIAL)
60 CITIES OF USA

22. Thromboprophylaxis After Trauma

23. Thromboprophylaxis after Trauma
Venous thromboembolism is common after major trauma.
A prospective surveillance study- 349 severely injured patients showed that without
prophylactic anticoagulation, proximal deep-vein thrombosis 18% of patients, pulmonary
embolism 11%.
Upto 37% of all symptomatic pulmonary emboli occur within the first 4 days after trauma.
Fatal pulmonary embolism is less common (0.4 to 4.2%) - 12% of all deaths after major trauma,
half of deaths are preventable.
Therefore, effective thromboprophylaxis is of paramount importance.

24. Risk /Benefits
Delay of more than 1 to 3 days in
initiating thromboprophylaxis ,in
severely injured patients triples
the risk of venous
thromboembolism
• BENEFIT
Prophylactic anticoagulation
associated with an odds ratio of more
than 13 for progressive enlargement
of hematoma in patients with
traumatic brain injury.
• RISK

25. Prophylactic IVC filter –
Challenging Decision
Retrievable inferior vena cava filters have
been developed
Primary means to prevent pulmonary
embolism @ trauma centers.
limited high-quality data to this approach

26. Based on large observational studies and one
randomized trial , for most severely injured
trauma patients, routinely placing prophylactic
IVC filters IS not yet recommended.
However, it is reasonable to use IVC filters in
very-high-risk patients, particularly if there are
ongoing contraindications to anticoagulation.

28. Hypothesis
• Early placement of a vena cava filter might
reduce the risk of symptomatic pulmonary
embolism in severely injured patients in
whom prophylactic anticoagulation is
contraindicated.

29. Multicenter, randomized, controlled trial
Insertion of a retrievable vena cava filter
within 72 hours after admission for
trauma
Incidence of pulmonary embolism
assessed, than no filter in this group of
patients.

30. METHODS

31. TRIAL DESIGN AND OVERSIGHT
• FOURTY TERTIARY CARE HOSPITALS IN AUSTRALIA
• FUNDED BY MEDICAL RESEARCH FOUNDATION
OF ROYAL PERTH HOSPITAL
• NO FINANCIAL SUPPORT BY THE ICVF
MANUFACTURERS

32. TRIAL POPULATION

33. INCLUSION CRITERIA
AGE MORE THAN 18 YEARS
Contraindications to pharmacologic thrombo-
prophylaxis within 72 hours of hospital
admission
Injury Severity Score >15

34. EXCLUSION CRITERIA
Severe head or systemic injury, death within 48 to 72hrs is expected
Receive pharmacologic thromboprophylaxis within 3 days after major trauma
CT evidence of pulmonary embolism on admission to the hospital
Treated with full systemic anticoagulation by warfarin, UFH. LMWH
Pregnancy , Age <18 years old
IVC filter cannot be inserted within 72hrs of trauma admission

35. INJURY SEVERITY SCORE (ISS)
Anatomical scoring system
6 body regions (head, face, chest, abdomen, extremities including
pelvis, external)
Abbreviated Injury Scale (AIS) between 0 and 6, 7
ISS is equal to the sum of the squares of the highest three AIS
scores.
If there is a non-survivable injury to one region the AIS equals 6
and the ISS score is automatically assigned the maximum of 75.

36. RANDOMISATION

38. PROCEDURES
Randomly assigned to receive either a retrievable filter (vena cava filter
group) or no filter (control group).- permuted block scheme.
For safety reasons, patients and the treating clinicians were aware of the
group assignments.
To minimize detection bias, proactive approach to detect symptomatic
pulmonary embolism, with strict guidelines regarding when CTPA
pulmonary angiography be performed

40. PROCEDURES cont…
All patients underwent routine Doppler and compression
ultrasonography of the legs 2 weeks after .
Avoid unnecessary radiation from routine CTPA
asymptomatic pt.
To ensure the clinical safety of patients assigned to the
control group through early detection of mildly PE / DVT,
reducing risk of fatal PE
Deaths referred to Coroner’s Court, & full postmortem if
needed, To determine whether pulmonary embolism was the
cause of death.

41. Procedures cont…
The type of filter used was at the discretion of the IR
All filters were removed as soon as prophylactic
anticoagulation was safely established or before 90 days,
unless needed to extend .
All filters retrieved were analyzed for integrity at the
Centre for Implant Technology and Retrieval Analysis.

42. PROCEDURES cont…
Initiation of prophylactic anticoagulation as soon as
clinically feasible was recommended- clinician
decision
Intermittent pneumatic compression to uninjured legs.
Allowed to insert a filter for patients to the control
group if there was a well-established indication.

43. PROCEDURES cont…
Insertion of IVCF by trained interventional radiologist
Removal of IVCF by hospital discharge or till 90 days
Reason of extended filters were mentioned
Crossover was allowed when clinically needed ,anticogulation can be
started even if inserted IVCF within 7 days
Attending Physicians were not blinded

44. Primary end points
1-Symptomatic pulmonary embolism within 90
days after enrollment
2- Death
3- Additional primary end point:
COST EFFECTIVNESS

45. SECONDARY END POINT
Symptomatic PE ( Fatal / non Fatal)- 08 to 90 days,, who did not
received anticoagulant prophylaxis within 7 days.
Complications related to filters
All cause 90 days or hospital mortalitiy
Bleeding at 90 days
Additional secondary outcome: DVT at 90 days found on 2 weeks
USG

46. STATISTICAL ANALYSIS
Previous study ( NEJM- 1994)- pulmonary
embolism occurred in more than 9% of severely
injured patients who did not receive
prophylactic anticoagulation.
A similar incidence was anticipated in this trial
because of the proactive approach used to
detect symptomatic pulmonary embolism in
patients with a high ISS and a high TESS

47. Primary and secondary end points were analysed according to the
intention-to-treat principle
For the primary end point, Cox proportional-hazards regression was used
to generate the hazard ratio and 95% confidence interval, and the log-
rank test was used to generate the P value
Included all patients who had undergone randomization, regardless of
their adherence to the protocol or subsequent crossover to receive or
decline the filter.
secondary end points analyzed with Miettinen and Nurminen method
at day 90 without the exclusion of deaths, with the intention-to-treat
principle, and reported as relative risks and 95% confidence intervals.

48. Complications related to the vena
cava filters are reported.
Cox proportional-hazards regression of
primary end point

50. RESULTS
• June 2015 – to December 2017, 1714 screened,
240 enrolled.
• Crossover of 2 patients in each group
• Median age 39 yr
• Median ISS 27
• Traumatic brain injury- 138 (57.5%), hematoma,
contusion
• Charactersitic- balanced between groups
• IVC FILTER: inserted within 24 hr in 89 %

51. RESULTS
Primary & secondary End points
 27 patients died after enrollment,( 16 IVCF,
11 control )
Postmortem also done on 9 PATIENTS
1 case of fatal saddle embolism (control
group, died 16th day, 8 days after prophylactic
anticoagulation)

52. RESULTS
Primary End points
• Incidence of PE/ death: 13.9 % IVCF vs 14.4 % Controls
p=0.98
• Only age and ISS is associated with primary end point
according to cox propotional hazard regression analysis

53. Secondary outcome
Symptomatic PE in Patients who survived for 7 days and no
anticoagulation within 7 days ( 46 IVCF group, 34 control
group)
None of patient in IVCF group had PE symtopmatic
5 Patients ( 14.7 % 0 control group had
symptomatic PE

56. Kaplan- Meire analysis of Primary End points

57. DISCUSSION
Primary prevention of PE- IVCF have
gained popularity for patients with high
bleeding risk
Conflicting recommendation by different
societies- ACCP, SIR.

58. EARLY AND PROPHYLACTIC IVCF- DID NOT LOWER THE INCIDENCE OF
SYMPTOMATIC PE.
Anticoagulation was initiated within 7 days after severe injury in 67%
of the patients enrolled in our trial.
33% of patients with ongoing contraindications to prophylactic
anticoagulation in whom anticoagulation could not be started within
7 days after severe injuries, symptomatic PE developed in none of
the patients assigned to the vena cava filter group.

59. EARLY IVCF-no urgency- risk and cost to be considered.
An entrapped thrombus was found within the filter in almost
5% of the patients in whom a filter was placed
However, multiple injuries / need for multiple surgeries,
intracerbral hematomas, may benefit from the use of a
vena cava filter as a temporizing measure to prevent
symptomatic pulmonary embolism.

60. • Increased DVT risk with IVCF was not found in
this trial, as opposed previous trials:-
– Use of intermittent pneumatic compression
– The initiation of prophylactic anticoagulation,
– The removal of the filter as early as possible.
DISCUSSION cont…

61. Cervical spine injury- immobilization, barrier to
retrieval of IVC filter.
The use of vena cava filters that can be removed
through femoral veins would thus be preferable in
these patients.

62. LIMITATIONS
1- Designed on the premise that a sizable protective effect is
needed to justify the costs and risks of a vena cava filter, was
underpowered to detect a modestly lower incidence of
symptomatic PE or death in the vena cava filter group than in
the control group.
2- several caveats to consider in secondary end point results,
– To survive to 7 days to qualify for inclusion
– This subgroup could be relatively less sick and conceivably
at a lower risk for pulmonary embolism than patients who
died earlier

63. In addition, the presence of filters may have
influenced decisions to initiate anticoagulation,
which introduces potential bias by having more
patients with a higher bleeding risk in the
control group.
Finally: trial was not blinded.
LIMITATIONS

64. CONCLUSION
Early placement of a vena cava filter after
major trauma did not result in a lower
incidence of symptomatic pulmonary
embolism or death at 90 days (the primary
composite end point) than no placement of
a filter.