There were 343 patients entered into the database (174 male and 169 female) over the 9-year period. The mean age for men was 59.8 years (range 19-87) and for women was 58.8 years (range 18-88). All IVC filter insertions were performed in our institution, 7 filters were retrieved in an external institute, the remaining filters were retrieved in our hospital.
The IVC filter types inserted were the Celect filter (Cook Medical, Bloomington, Indiana) in 189, the Gunther Tulip (GT) (Cook Medical, Bloomington, Indiana) in 65, ALN (ALN, Ghisonaccia, France) in 89.
The access routes for insertion approach were the right internal jugular vein in 278 cases (81%), right common femoral vein in 58 cases (17%) and the left common femoral vein in 7 cases (2%). A diagnosis of malignancy at the time of filter insertion was reported in 115/343 (33.5%) patients. 30 of these 115 patients (26%) had a permanent IVC filter inserted de novo. Limited life expectancy independently or combined (Table 1) constituted 53 (49%) permanent filters with 9/53 (17%) also having a malignancy status.
Table 1
Indications for Permanent Filters (n =108)
Indications for Permanent Filters | Number of Cases |
Limited Life Expectancy | 30 (27.7%) |
Long-term CI to AC | 28 (25.9%) |
Failed Retrieval | 13 (12%) |
VTE on therapeutic AC | 10 (9.3%) |
Patient Preference | 4 (3.8%) |
Multiple - Limited Life Expectancy + Long-term CI to AC 13 (12.6%) - Limited Life Expectancy + VTE on AC 10 (9.7%) | 23 (21.3%) |
Overall total | 108 |
Indications for insertion of IVC filters were separated into 6 categories: contraindication to anticoagulation in setting of VTE in 147 (43%), pre-operative prophylaxis (Patients with a previous history of VTE undergoing major surgery) in 117 (34%), pharmaco-mechanical thrombectomy in 47 patients for iliofemoral DVT (14%), VTE on therapeutic anticoagulation in 20 (6%), extensive VTE in 5 (1%) and multiple indications in 7 (2%), as shown in (Table 2).
Table 2
Indications for Filter Insertion (n=343)
Indications for Filter Insertion | Number of Cases (%) |
CI (Contraindication) to AC (Anti-Coagulation) | 147 (42.7%) |
Pre-operative prophylaxis | 117 (34.1%) |
Pharmaco-mechanical thrombectomy (PMT) | 47 (13.7%) |
VTE (Venous Thromboembolisim) on AC | 20 (5.8%) |
Extensive VTE | 5 (1.7%) |
Multiple - CI to AC + extensive VTE 2 (0.6%) - CI to AC + PMT. 2 (0.6%) - Pre-operative + VTE on AC 1 (0.3%) - PMT + extensive VTE 1 (0.3%) - pre-operative + CI to AC 1 (0.3%) | 7 (2.0%) |
Overall total | 343 |
Of the 343 filters inserted, 196 (57.1%) filters were retrieved, 108 (31.5%) filters were deemed permanent, 36 (10.5%) patients died during follow-up, and 3 (0.9%) patients were yet to be retrieved or lost to follow up. The overall retrieval rate was 92.5% (Fig. 2), with a retrieval rate of 86% for GT, 93% for Celect and 94.5% for ALN (Table 3).
Table 3
Retrieval Rate by Filter Type (n=343)
Filter Type | Filter Status | Total | Retrieval |
Retrieved | Permanent | In situ | Deceased | Failed * | Successful retrieval |
Gunther Tulip | 18 | 42 | 0 | 5 | 65 | 3 | 86% |
Celect | 126 | 44 | 2 | 17 | 189 | 8 | 93% |
ALN | 52 | 22 | 1 | 14 | 89 | 2 | 94.5% |
Overall total | 196 | 108 | 3 | 36 | 343 | 13 | 92.5% |
* Failed category totals are a subset of the permanent category totals. |
The mean dwell time for successful retrieval was 59 days (median 42, range 2-390 days) with the majority of insertions (85%) removed in under 100 days (Table 4).
Table 4
Mean dwell time by Filter Type (n=209)
Filter Type | Successful cases | Failed Cases | Length of Time until retrieval |
Quantity | Mean No. of days until retrieval | Quantity | Mean No. of days until attempted retrieval | Max days | Min days |
Gunther Tulip | 18 | 50 | 3 | 63 | 144 | 15 |
Celect | 126 | 58 | 8 | 73 | 336 | 2 |
ALN | 52 | 67 | 2 | 81 | 390 | 4 |
Total | 196 | 59 | 13 | 72 | | |
Before insertion, 61 patients were streamed into the ‘permanent filter’ group, 48 were streamed into the ‘unspecified plan’ group and the remaining 234 were streamed into the ‘intent to retrieve’ group.
Of the 48 patients in the ‘unspecified plan’ group a later decision with regard to the filter being retrieved or deemed permanent was made within 3 months of filter insertion after discussion of the clinical condition of the patient with the referring physician. Of these 48 patients, filters were assigned permanent status in 35 due to deteriorating clinical illness and poor life expectancy and 13 were assigned to the intent to retrieve group. Of the latter 13 patients, 6 filters were retrieved ,6 died before IVC retrieval and 1 was lost to follow up.
In the ‘intent to retrieve’ group, 190 of 234 filters were retrieved either on first or second attempt. 30 patients of the 234 died prior to retrieval, 12 were made permanent and 2 were lost to follow up.
As stated, 61 filters were deemed permanent from the time of insertion, all 61 remained in situ. On final review, filters were assigned the status of permanent in 108, (42 Gunther Tulip, 44 Celect, and 22 ALN). The clinical circumstances under which the determination for the filter to remain permanently is shown in Table 1. This means that a permanent status was applied to a filter in 47 patients, who before insertion were streamed initially into the ‘intent to retrieve’ group or ‘unspecified plan’ group.
Unsuccessful retrieval at the first attempt occurred in 23 patients. Table 5 shows the causes for failed retrievals on the first attempt. 13 (57%) patients who had an unsuccessful retrieval on the first attempt went on to become permanent after discussion with the patient and referring teams (these cases were then considered a ‘failed retrieval’) and 10 (43%) were successfully retrieved on the second attempt. Advanced manoeuvres were used in 19 cases overall with 13 (68%) resulting in successful retrieval. 9 (39%) of the 23 initial failed attempts had advance manoeuvres performed. In filters with thrombus at the time of retrieval, the patients remained on anticoagulation and a further date for retrieval planned in 2-3 weeks time. Retrieval on second attempt was successful in 50% (5/10) of these cases.
Table 5
Reasons for failed initial retrieval (n=23)
Reason for failed initial retrieval | Number of Cases |
Thrombus in filter | 10 (43.5%) |
Endothelialized | 5 (21.7%) |
Re-inserted above filling defect | 2 (8.7%) |
Filter tilted/ Unable to snare | 1 (4.4%) |
Access route thrombosed | 1 (4.4%) |
Multiple - Endothelialized and thrombus in filter 3 (13.0%) - Endothelialized and unable to snare 1 (4.4%) | 4 (17.4%) |
Overall total | 23 |
The most commonly employed advanced manoeuvre was the loop snare technique, this involves engaging a reverse curve catheter in the struts of the filter and inserting a hydrophilic wire cranially. The wire is then snared and externalized, thus used as a counter force as the co-axial sheath is passed over the collapsed IVC filter. Another advanced manoeuvre performed in two cases involved passing a wire between the endothelialized hook and wall of the IVC. A balloon venoplasty was performed in an attempt to separate the hook from the IVC wall and thus allow for the hook to be snared. A semi rigid forceps with a larger 16 French sheath was used successfully in 3 patients when some of the above retrieval methods failed.