Patient demographics (overall):
A total of 94 IVC filters were inserted over the study period.
This figure includes filters re-instated in 2 patients after initial removal (both with VTEs and ongoing requirement for surgery).
51 (54.3%) of patients were male Fig. 4,
and the age range 17-91 years (median age 64) as in Fig. 5.
The majority of referrals came from the surgical specialities (Fig. 6),
probably due to the original cause of admission being surgical in nature e.g.
polytrauma (example,
Fig. 7,
Fig. 8 ),
or from patients developing VTE in the peri-operative phase.
Fig. 9 demonstrates the outcomes of filters in this study.
Retrieval:
60 (63.8% of total) filters were retrieved.
The median age of this patient cohort was 61 years.
The time to filter retrieval varied between 0-151 days post-insertion (median 17.5 days),
with the majority (41/60) retrieved within 30 days post-insertion.
No serious or life-threatening complications were associated with retrieval.
There was a delay in retrieving 5 filters,
due to the following reasons: 3 filter thrombus, 1 iliac vein thrombus,
1 failure to engage filter.
These findings were encountered between days 8 to 30 post-insertion.
Non-retrieval:
34 (36.2% of total) filters were left in-situ.
The median age of this cohort was 69.5 years. No retrieval attempt was made in 32 cases.
Retrieval was attempted,
but abandoned in the remaining 2 cases: 1 patient was found to have a large filter thrombus on day 332.
1 other had a tilted filter,
difficult to snare on day 10; no further attempts were performed as the patient was 90 years old.
15/34 (44.1%) were declared permanent due to contra-indications to removal.
10/34 (29.4%) patients died within 30 days of filter being in-situ.
6 filters were lost to follow-up.
Of these,
4 patients were repatriated to other hospitals,
with no subsequent filter retrieval performed by local interventional radiology teams.
1 patient was discharged from the authors' institution with no known address or contact number.
The remaining 1 patient was intended for outpatient filter retrieval according to their discharge plan,
however the patient was subsequently lost to follow-up.
The 'lost to follow-up' group comprises 6.4% of all inserted filters within the study period.
Booking of retrieval date:
A provisional retrieval date had been arranged in 37 cases.
32 of these filters were eventually retrieved.
Correspondingly,
this translates to a date pre-booked by radiology in 53.3% (32/60) of the retrieved filter caseload.
In 4 cases,
the radiologist suggested designating the filter permanent due to patient age or co-morbidities.
2 of these filters were left in-situ,
contributing to 5.9% of all non-retrieved filters.