Indications for insertion of IVC filters were separated into 7 categories and are listed in Table 1. Of the 536 filters, 31 filters were permanent, nonretrievable, while 505 were classified as retrievable. Ten complications occurred during the removal of permanent filters, while 22 occurred during the removal of retrievable filters, yielding complication rates of 32.3% and 4.4%, respectively. The complication rates associated with the removal of specific types of permanent filters and retrievable filters are summarized in Tables 2 and 3, respectively. At the time of removal, approximately 18 filters were already fractured. Three minor complications were observed during the retrieval of these fractured filters. Overall, 97.9% (525/536) of the filters were successfully removed, with a 6.0% complication rate (32/536). Filters that were not successfully removed were left in the IVC. The standard snare technique was attempted in 347 retrievals, isolated forceps were utilized in 105 cases, and a combination of both standard snare technique and forceps was used in 68 cases. Removal was not attempted in seven cases due to chronic thrombus where risks of removal outweighed benefits and/or recurrent pulmonary embolism. Success rates and graded complication rates for these different retrieval techniques are summarized in Tables 4 and 5.
The standard snare technique exhibited a success rate of 99.4% (345/347), with 1.7% (6/347) of patients experiencing complications. Among these filters, 9 were permanent, and 338 were retrievable. The majority of the complications in this cohort were low grade complications (Two Grade 1; 2/347, 0.58% and three Grade 2; 3/347, 0.86%). One patient experienced retroperitoneal bleeding after standard IVC filter removal (Grade 3; 1/347, 0.29%). A higher complication profile was seen in removal of permenant filters (2/5 complications, 40%). Filters removed with the standard snare technique had a mean dwell time of 658 days, ranging from 1 day to 5713 days. The median dwell time was 221 days.
Among all cases in which forceps retrieval was attempted, there was an overall 98.8% success rate (171/173). Filter retrieval utilizing only forceps had a 99.05% (104/105) success rate, though it also exhibited a higher complication profile compared to standard snare technique: 13.3% (14/105). Furthermore, higher grade complications were more prevalent with forceps retrieval (one Grade 4; 1/105, 0.95%; IVC rupture requiring intra-procedural placement of thoracic aortic stent graft, and two Grade 3; 2/105, 1.9%; retroperitoneal bleeding delaying discharge or requiring later hospitalization). Higher grade complications (grade 3 and 4) soley occurred during the removal of permanent filters. Eight low grade complications were observed (one Grade 1: 8/105, 7.6%; and three Grade 2 complications 3/105, 2.9%). The majority of low grade complications occurred with the removal of retrievabale filters (7/11, 63.6%). The mean dwell time was 2778 days, with a minimum dwell time of 1 day and a maximum of 10,075 days. The median dwell time was 2917 days.
Combined standard snare technique and forceps retrieval (failed snare removal converted to forceps or planned concurrent use of forceps and snare) was successful in 98.5% (67/68) of attempted removals, and complications occurred in 16.2% (11/68) of these procedures. Primarily, only low grade complications were observed with combined technique (five Grade 1 5/68, 7.4% and six Grade 2 6/68, 8.8%). Two of these minor complications (2/11, 18.2%) occurred during the attempted retrieval of a permanent filter. The mean dwell time was 1364 days (range: 4–7470 days). The median dwell time was 568 days. Of note, 51 of the 68 combined procedures involved conversion of failed standard snare retrieval to forceps retrieval.
As expected for a more complex procedure, radiation exposure was higher among patients undergoing forceps-directed retrieval. Standard snare technique resulted in an average of 7.4 minutes of fluoroscopy time, while forceps-directed retrieval (including simultaneous forceps and standard snare retrieval) resulted in an average fluoroscopy time of 18.2 minutes.
Any attempted filter removal that utilized forceps, regardless of concurrent technique, was classified as a forceps-directed retrieval for statistical analyses. Filters retrieved with forceps had a statistically significant longer dwell time (median: 1734 days; range(1–10,075 days) compared to filters removed with the standard snare technique (median: 221 days; range(1–5713 days), (p < 0.001). Despite this difference in dwell time, there was no statistically significant difference in retrieval rate between these two techniques (p = 0.60). However, complications were less likely in the standard snare technique group compared to the forceps retrieval group (OR:0.10; 95%CI:0.04–0.25), (p < 0.001).
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