The optimal use of retrievable IVC filters remains unclear. We compared our recent 5-year experience with retrievable filters placed for prophylactic or therapeutic indications.
Methods
A retrospective, single institution chart review was performed to identify patients who had a retrievable filter placed between July 2002 and December 2007. Patient data included age, sex, admitting diagnosis, indication for filter, dates of insertion, retrieval/attempted retrieval and reasons for unsuccessful retrieval. Comparisons were made by Chi-square testing.
Results
During the study period, 462 retrievable filters were placed in patients who had a confirmed diagnosis of VTE (or were considered high risk for VTE) who also had an absolute or relative contraindication to anticoagulation. Overall, a retrieval attempt was made in 201 (44%) patients and was successful in 174 (87% of attempts but only 38% of all filters placed) [See table]. Retrieval was much more likely to be attempted in patients who received filters for prophylactic (64%) v therapeutic (28%) indications (p < 0.0001). Lack of an attempt to retrieve the filter was due to loss of follow-up (n = 141; no difference between prophylactic or therapeutic groups), contraindication to anticoagulation (n = 75), or patient death (n = 46). Retrieval failure (n = 27) was due to: filter ingrowth (n = 11), retained thrombus (n = 10), or tilt (n = 6). Duration of implantation >30 days was strongly and inversely correlated with retrieval success [<30 day retrieval rate = 92% (131/142), >30 day retrieval rate = 73% (43/59); p = 0.0002].
Comparison between Prophylactic & Therapeutic Filters
Prophylactic (no confirmed VTE)
Therapeutic (confirmed VTE)
N [Total = 462] (%)
194(42)
268(58)
Attempted Retrieval (%)
125(64)
76(28)
Successful Retrieval (% of attempts)
111(89)
63(84)
Retrieval Rate (%) by Diagnosis
Trauma (n = 114/188, 61%)
98/150(65)
16/38(42)
Cancer (n = 10/85, 12%)
1/10(10)
9/75(12)
Neuro (n = 6/34, 18%)
3/8(38)
3/26(12)
Ortho (n = 11/32, 34%)
4/13(31)
7/19(37)
Other Med/Surg (n = 33/123, 27%)
5/13(38)
28/110(25)
Conclusions
The only group with a >50% retrieval rate were trauma patients who received prophylactic filters. All other patient groups were more likely to have their filters left in permanently. If attempted, retrieval rates were relatively high regardless of indication or underlying diagnosis although duration of implantation was a significant factor in unsuccessful filter retrieval.
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