Prophylactic placement of vena caval filters: A cautionary note

Greenfield filter placement in patients without deep venous thrombosis has been performed when such patients were felt to be at high risk for asymptomatic deep venous thrombosis and subsequent embolus. In this group placement is termed truly prophylactic to differentiate from placement in a patient with documented deep venous thrombosis which has not yet embolized. A retrospective review of Greenfield filter placement at five Dayton, Ohio, community hospitals over three years revealed 59 filters placed in 58 patients. Of these 90% were placed surgically and 10% percutaneously at an average cost of $4,141.00 per surgical procedure. Indications included traditional as well as true prophylaxis. A low morbidity and no mortality related to filter placement was observed. The high efficacy and safety of filter placement seen at large institutions is also found in our community hospital experience despite placement by physicians who perform the procedure infrequently. Although filter placement in patients at a high risk for silent fatal pulmonary emboli may prevent a rare mortality, widespread use of this modality for pulmonary embolus prophylaxis is costly and not without patient risk. We caution against the use of Greenfield filters for pulmonary embolus prophylaxis in patients without deep venous thrombosis until evidence of superior efficacy compared to other forms of prophylaxis can be demonstrated. Presented at the Annual Meeting of the Peripheral Vascular Surgery Society, New York, New York, June 17, 1989. The opinions expressed herein are those of the authors and do not reflect the opinions of the United States Air Force or the Department of Defense.     

Comparative efficacy and complications of vena caval filters

Purpose: A variety of vena caval filters (VCFs) are available for usage. The choice of filter type depends on physician preference and certain patient variables. An evaluation of the different VCFs used in our institution was done to compare their efficacy and complication rates.Methods: The medical records of all patients who underwent insertion of a VCF from January 1987 to June 1993 at the University of Iowa Hospitals & Clinics and the affiliated Veterans Administration Medical Center were reviewed. One hundred ninety-nine VCFs were placed in 196 patients (123 males, 73 females), with a mean age of 61 years (range 13 to 87 years). Thirty-five (18%) VCFs (30 stainless steel Greenfield filters [SGFs] and five titanium Greenfield filters with modified hook [TGF-MHs]) were inserted in the operating room via an open technique. The remaining 164 VCFs (82%) were inserted in the radiology suite by a percutaneous technique (38 SGF, 23 TGF-MH, 51 Vena Tech filters [VTFs], 48 Bird's nest filters [BNFs] and 4 Simon Nitinol filters). Thromboembolic risk factors in these 196 patients included malignancy (99), trauma (21), recent surgery (27), cerebrovascular accident with paralysis (6), and miscellaneous conditions (43). Indications for VCF placement included a contraindication to anticoagulation (92), complication of anticoagulation (44), failure of anticoagulation (26), prophylaxis (31), adjunct to pulmonary embolectomy (1), noncompliance (1), hemodynamically unstable patient (1), and prior VCF complication (3). Mean follow-up of the patients was 12 months (range 0 to 87 months). Because there were only four Simon Nitinol filters inserted during the study period, they were excluded from further analysis.Results: A comparative analysis revealed that there was a significantly higher incidence of symptomatic IVC thrombosis with the use of the BNF (n = 7) (14.6%) versus the SGF (n = 0) (0%), TGF-MH (n = 1) (3.6%), or VTF (n = 2) (4%) (p < 0.05 by chi-squared testing). The VCF-related mortality rate was also higher with the BNF (n = 5) (10.9%) versus the SGF (n = 1) (1.5%), TGF-MH (n = 1) (3.6%), or VTF (n = 0) (0%) (p < 0.05 by chi-squared testing). However there was no significant difference in the occurrence of clinically apparent recurrent pulmonary embolism during follow-up between the four different filter types (2 [4.2%] BNF, 3 [4.4%] SGF, 1 [3.6%] TGF-MH, and 1 [2%] VTF).Conclusion: These data indicate that the use of the BNF was associated with increased morbidity and mortality rates compared with the use of the SGF, TGF-MH, and VTF filters. (J VASC SURG 1995;21:235-46.)     

Prophylactic and therapeutic inferior vena cava filters to prevent pulmonary emboli in trauma patients

HYPOTHESIS: Insertion of inferior vena cava filters (IVCFs) can prophylactically reduce pulmonary embolism (PE) in trauma patients. DESIGN: Retrospective review. SETTING: Urban, level I trauma center. PATIENTS: Two hundred blunt trauma patients undergoing IVCF placement. INTERVENTIONS: In 122 patients who had already been diagnosed as having deep vein thrombosis (DVT) (112 patients) and/or PE (22 patients), the insertion of the IVCF was considered "therapeutic." In 78 patients who had no evidence of DVT or PE but who were considered to be at high risk for a PE, the IVCF was considered "prophylactic." MAIN OUTCOME MEASURES: Incidence of PE and related mortality and morbidity in therapeutic vs prophylactic IVCFs. RESULTS: The number of prophylactic IVCFs inserted increased significantly from only 4% (3/68 cases) from 1991 through 1996, up to 57% (75/132 cases) from 1997 to June 2001. Although the mean +/- SD age (51 +/- 20 years vs 41 +/- 15 years; P<.001) was higher in the therapeutic group, there was no difference in the mean +/- SD Injury Severity Scores (20 +/- 12 vs 21 +/- 11). Therapeutic filters were placed much later after injury (mean +/- SD time, 11 +/- 7 vs 3 +/- 2 days; P<.001). The mortality rate was 11% (13/122 patients) in patients having a therapeutic IVCF, as compared with only 3% (2/78 patients) in those placed prophylactically (P =.07). None of the patients who had placement of a prophylactic IVCF developed subsequent PE. The incidence of PE decreased in all blunt trauma patients from 0.29% before 1997 to 0.15% after January 1, 1997, when 57% of the IVCF inserted were prophylactic (P =.06). CONCLUSIONS: Prophylactic IVCFs should be inserted within 48 hours of injury in specific trauma patients at high risk for PE and with contraindications to anticoagulation.     

Operative removal of misplaced Greenfield vena caval filters

Operative retrieval has not been necessary in our experience, though interest has been expressed by other surgeons. Specifically, during removal the hooks of the filter may become attached to adjacent structures, making manipulation and eventual extraction difficult. Because the occasion for late removal of a misplaced filter may arise, we have developed this method using readily available materials. We anticipate that this technique will be most useful for removal of filters that have been in place for more than 7 days. A method to retrieve filters in place less than 1 week has already been reported [4]. We have found the technique quite satisfactory in experimental animals.     

Prophylactic indications for vena cava filters: critical appraisal

Vena caval filters (VCFs) were developed and initially used for therapeutic indications, primarily to prevent recurrence of pulmonary embolism (PE) or its occurrence in selected cases of deep venous thrombosis (DVT), where risk of PE was very high and anticoagulant therapy (AC Rx) was deemed ineffective, contraindicated by concurrent disease, or had to be discontinued because of complications. Prophylactic indications-where there was no DVT or PE but the risk of them was considered very high and AC Rx was contraindicated or considered ineffective-were invoked relatively infrequently at first, but when percutaneous placement became routine in the late 1980s, this indication increased steadily. The categories of patients considered at high-enough risk of venous thromboembolism (VTE), albeit temporary, to justify VCF have also expanded steadily, most with little objective basis for choosing VCFs over other methods of prophylaxis. In many of these prophylactic categories, eg, patients undergoing surgery associated with a high risk of VTE, the risk is for a limited period only, until the patient is ambulatory or AC Rx can be instituted. In addition, there are potential disadvantages to leaving a permanent filter in, especially in younger patients with an extended longevity outlook and no ongoing risk of VTE. This was brought out in the PREPIC trial. This realization has, in turn, spurred interest in developing temporary or retrievable filters for short-term prophylactic use. No design has yet proven entirely satisfactory for this purpose, but the practice of placing such filters for prophylactic indications has steadily grown, using available devices. This article critically reviews these trends, suggests directions for future developments, and recommends necessary studies on which to base the practice of prophylactic VCF use.     

The role of vena caval filters in the management of venous thromboembolism

Deep venous thrombosis (DVT) and pulmonary embolism (PE) are important, and not infrequent, causes of morbidity and mortality in critically ill patients. Anticoagulation remains the treatment of choice for DVT and PE, but contraindications to, and complications from, anticoagulant therapy mandate the availability of alternate therapeutic and prophylactic strategies. The recent availability of safe and effective vena caval filters that can be inserted via a minimally invasive percutaneous approach has expanded the indications for, and acceptance of, these devices in selected patients at high risk for the development of PE. This article reviews both the established and the evolving indications for vena caval filters and discusses how improvements in filter design may impact future use.     

Experience with the insertion of vena caval filters in acutely burned patients

The use of inferior vena caval filters in patients at high risk of pulmonary emboli is a standard practice in many types of patients. The usefulness of such filters in acutely burned patients has yet to be established. Twenty inferior vena caval filters were inserted in burn patients. Five were inserted because of preexisting thromboembolic disease. Fifteen were placed prophylactically because of high-risk states, including prolonged immobilization, old age, bleeding problems, and obesity. There were no complications due to filter insertion. No postinsertion emboli were recognized. There were no cases of postinsertion thrombophlebitis. In this small series, the procedure appears to be effective and safe.     

Abdominal computed tomography and the placement of inferior vena caval filters

BACKGROUND: Standard cavography is performed with iodinated contrast material with plain film or digital subtraction technique. However, preplacement imaging may change final inferior vena cava filter (IVC) placement in 11 to 26% of patients. This study will examine the use and reliability of incidental spiral computed abdominal tomography (CAT) scans for the placement of IVC filters. METHODS: Over a 25-month period, CAT scan data were prospectively collected on patients at high risk for pulmonary embolism (PE) or with PE that required an IVC filter. CAT scans were then evaluated specifically for vena cava anatomy and relationship to renal veins and lumbar spine. IVC filters were then placed before cavography under fluoroscopy (performed only to confirm accurate placement) based on the static relationship of the renal veins/IVC and spine. RESULTS: One hundred twenty-two patients had IVC filters placed. In the last 78 eligible patients, CAT scan placement was verified with post deployment cavography. IVC filters were deployed an average of 3.25 mm below the lowest renal vein with no veins misidentified. No strut malposition was noted on post deployment cavography. 12.1% had findings by CAT scan that altered some aspect of IVC filter placement. CONCLUSIONS: Admission or same hospital stay spiral CAT scan can provide enough anatomic detail to safely guide placement of an IVC filter. IVC filters can be deployed at bedside without contrast cavography if the preplacement CAT scan is adequate.     

Prophylactic inferior vena cava filters in trauma patients at high risk: Follow-up examination and risk/benefit assessment

Purpose: The efficacy of prophylactic inferior vena cava filters in selected trauma patients at high risk has come into question in relation to risk/benefit assessment. To evaluate the usefulness of prophylactic inferior vena cava filters, we reviewed our experience and overall complication rate. Methods: From February 1991 to April 1998, the trauma registry identified 7333 admissions. One hundred eighty-seven prophylactic inferior vena cava filters were inserted. After the exclusion of 27 trauma-related deaths (none caused by thromboembolism), 160 patients were eligible for the study. The eligible patients were contacted and asked to complete a survey and return for a follow-up examination to include physical examination, Doppler scan study, vena cava duplex scanning, and fluoroscopic examination. The patients’ hospital charts were reviewed in detail. The indications for prophylactic inferior vena cava filter insertion included prolonged immobilization with multiple injuries, closed head injury, pelvic fracture, spine fracture, multiple long bone fracture, and attending discretion. Results: Of the 160 eligible patients, 127 were men, the mean age was 40.3 years, and the mean injury severity score was 26.1. The mean day of insertion was hospital day 6. Seventy-five patients (47%) returned for evaluation, with a mean follow-up period of 19.4 months after implantation (range, 7 to 60 months). On survey, patients had leg swelling (n = 27), lower extremity numbness (n = 14), shortness of breath (n = 9), chest pain (n = 7), and skin changes (n = 4). All the survey symptoms appeared to be attributable to patient injuries and not related to prophylactic inferior vena cava filter. Physical examination results revealed edema (n = 12) and skin changes (n = 2). Ten Doppler scan studies had results that were suggestive of venous insufficiency, nine of which had histories of deep vein thrombosis. With duplex scanning, 93% (70 of 75) of the vena cavas were visualized, and all were patent. Only 52% (39 of 75) of the prophylactic inferior vena cava filters were visualized with duplex scanning. All the prophylactic inferior vena cava filters were visualized with fluoroscopy, with no evidence of filter migration. Of the total 187 patients, 24 (12.8%) had deep vein thrombosis develop after prophylactic inferior vena cava filter insertion, including 10 of 75 (13.3%) in the follow-up group, and one patient had a nonfatal pulmonary embolism despite filter placement. Filter insertion complications occurred in 1.6% (three of 187) of patients and included one groin hematoma, one arteriovenous fistula, and one misplacement in the common iliac vein. Conclusion: This study’s results show that prophylactic inferior vena cava filters can be placed safely with low morbidity and no attributable long-term disabilities. In this patient population with a high risk of pulmonary embolism, prophylactic inferior vena cava filters offered a 99.5% protection rate, with only one of 187 patients having a nonfatal pulmonary embolism. (J Vasc Surg 1999;30:484-90.)     

Suprarenal placement of vena caval filters: indications, techniques, and results

Preferred treatment for thromboembolism when heparin fails or is contraindicated is infrarenal inferior vena cava (IVC) interruption. In the present study suprarenal Greenfield filters were placed in 11 patients in whom routine infrarenal IVC interruption would have been inadequate therapy. As identified by IVC venography, nine patients, including two patients with renal vein thrombi and proteinuria, had partially attached IVC thrombi extending to or above the orifices of the renal veins. One patient had multiple life-threatening pulmonary emboli (PE) on anticoagulation therapy without a known source of emboli and a large patent ovarian vein, and another had an ovarian vein thrombus. Five patients (45%) had a contraindication to heparin therapy, and five (45%) had recurrent PE on anticoagulants. In follow-up (range 3 to 26 months, mean 12.3 months) there has been no documented or suspected recurrent PE, change in renal function, or peripheral edema. There were two deaths secondary to malignancy. IVC patency was demonstrated in all patients studied. Eight patients continue to receive anticoagulants. Based on our clinical experience, our data suggest that suprarenal filter placement is indicated in the following situations: (1) recurrent thromboemboli despite anticoagulation therapy with IVC thrombi extending to or above the renal veins, renal vein thrombosis, previous IVC interruption, or a large patent left ovarian vein or (2) documented perirenal IVC thrombi when anticoagulation therapy is contraindicated. The results of this study indicate that when thromboemboli originate at or above the level of the renal veins in the IVC, suprarenal IVC filter placement is effective therapy.     

Deep venous thrombosis after percutaneous insertion of vena caval filters.

PURPOSE: A large multicenter study has recently questioned the overall clinical efficacy of vena caval filters, especially when inserted prophylactically, because of the subsequent development of deep venous thrombosis (DVT) at the insertion site. We examined the incidence of this complication with newer, smaller diameter percutaneous devices. METHODS: We reviewed our vascular surgery and interventional radiology clinical registries to identify patients in whom a femoral percutaneous vena caval filter had been placed from 1993 to 1998. This list was cross referenced with patients who had undergone lower extremity venous ultrasound scan examinations for the diagnosis of DVT in the vascular laboratory within a 60-day period before and after the insertion of the filter device. RESULTS: A total of 35 patients during this 5-year period had timely follow-up venous duplex scan studies performed. The indications for filter placement were DVT in 16 patients (46%), pulmonary embolus in 13 patients (37%), DVT and pulmonary embolus in three patients (9%), and prophylactically in three patients (9%) at high risk for thromboembolization. Of the patients with documented thromboembolic events, 91% (29 of 32) had contraindications to anticoagulation therapy, and the remaining 9% (3 of 32) represented failure of anticoagulation therapy. A Greenfield filter was used in 13 patients (37%), a Simon Nitinol filter was used in 11 patients (31%), and a VenaTech filter was used in nine patients (26%). The other two patients (6%) had a Bird's Nest filter inserted. At a mean follow-up period of 12 +/- 2 days (median, 6 days), there was a 40% (14 of 35) incidence of proximal DVT in venous segments without evidence of thrombus before filter insertion. The majority (71%; 10 of 14) occurred in the common femoral vein, with three located in the superficial femoral vein and one in the external iliac vein. The lowest incidence of DVT was seen with the Greenfield and Bird's Nest filters as compared with the smaller Simon Nitinol and VenaTech filters (20% vs 55%; P < .05). The highest incidence of thrombosis occurred in patients with pre-insertion pulmonary emboli (50%; 8 of 16) as compared with those patients with DVT (38%; 6 of 16) and prophylactic insertion (0%; 0 of 3). However, the subgroups were too small to attain statistical significance. CONCLUSION: There is a continuing and significant incidence of new DVT development ipsilateral to the percutaneous femoral insertion site of vena caval filters. The smaller diameter filters are not associated with a lower incidence of femoral thrombosis.     

Comparison of titanium and stainless steel, Greenfield vena caval filters

The standard stainless steel Greenfield filter (SGF) requires a 24F-sized carrier system, and its insertion percutaneously has been associated with local venous thrombosis. To facilitate both percutaneous and operative insertion, a titanium model of the Greenfield filter (TGF) has been developed that allows use of a 12F-sized carrier system. Mechanical comparison of the SGF and TGF devices shows that both withstand extensive flexion stress, but the TGF has greater endurance (52 gm at 20 mm travel) than the SGF (48 gm at 5 mm travel). Measurement of lateral forces for fixation shows comparable force (4.5 gm) at 22 mm for each device but greater force for the TGF at diameters more than 22 mm to its resting diameter of 38 mm. The TGF also withstands crevice corrosion in hydrochloric acid and ferric chloride better than the SGF. Animal studies in 20 sheep show comparable fixation of both devices with no added thrombogenicity of the TGF. Thrombus capture and resolution studies after 14 days in dogs show comparable effectiveness, and histologic examination of the venae cavae show similar inflammatory cell reaction and fibrosis with no foreign body reaction for either metal. Both the SGF and the TGF demonstrate durability and effective filtration of thrombi, with the TGF having the added advantages of ease of insertion and potential improved fixation in larger cavae.     

Long-term follow-up of trauma patients with a vena caval filter

BACKGROUND: Venous thromboembolism (VTE) is an important complication in blunt trauma patients. At our Level I trauma center, we had a deep venous thrombosis (DVT) rate of 3.2% from 1993 to 1997 despite an aggressive VTE prophylaxis program. During this time period, we placed vena caval filters (VCF) for both traditional and prophylactic indications. This project was developed to establish a VCF registry for trauma patients to determine the long-term complications of VCF placement. METHODS: A letter was sent to all trauma patients who had a VCF placed from 1993 through 1997. Patients were asked to return for a history and physical examination to detect signs and symptoms related to VTE, a duplex ultrasound of the inferior vena cava, and a plain abdominal radiograph to determine filter migration. RESULTS: There were 191 VCFs inserted in our trauma population from 1993 to 1997. There were 105 patients (75 male and 30 female) available for evaluation, with a mean follow-up of 28.9 months. Forty-one VCFs were placed in patients with DVT or pulmonary embolism, and 64 were placed in patients for prophylactic indications as per the guidelines developed by the Eastern Association for the Surgery of Trauma. There were no clinically identifiable complications related to insertion of the VCF. There were no pulmonary embolisms detected after VCF insertion. In follow-up, only one filter (0.95%) migrated, and this was minimal (1 cm cephalad). One (0.95%) vena cava was occluded, based on duplex ultrasonography, and 11 patients (10.4%) had signs or symptoms of leg swelling after hospital discharge. Twenty eight (44%) of the 64 patients with prophylactic VCFs developed a DVT after filter placement. CONCLUSION: VCFs placed in trauma patients have acceptable short- and long-term complication rates. Consideration should be given to prophylactic VCF placement in patients at high risk for VTE. Randomized controlled trials are needed to evaluate whether VCF insertion increases the risk for subsequent DVT.     

Proximal migration of vena caval filters: Report of two cases with operative retrieval

Operative retrieval of two proximally migrated vena caval filters was performed in two patients, ages 42 and 45 years, respectively. In the first patient the filter was encrusted in the right ventricle, and in the second one the filter was found in the pulmonary artery. Both filters were retrieved under cardiopulmonary bypass via an incision in the right atrium and the pulmonary artery, respectively. These two observations underscore the risk of increased unwarranted indications and consequent higher complication rates of vena caval filters.     

Early technical and clinical results with retrievable inferior vena caval filters

Deep venous thrombosis with or without subsequent pulmonary embolism is a common preventable cause of hospital death. Although anticoagulation is the accepted standard therapy for thromboembolic disease, in situations in which anticoagulation is contraindicated, interruption of the inferior vena cava (IVC) by means of percutaneous placement of a filter has become a widely used alternative. We report our initial experience with two retrievable IVC filters. Between July 2002 and April 2003, 13 patients (mean age 54 +/- 7 years; range 29-75 years) underwent percutaneous placement of either the Gunther Tulip (n = 5; Cook Inc., Bloomington, IN) or OptEase (n = 8; Cordis, Miami Lakes, FL) IVC filter. Five patients had filters placed prophylactically before major surgery. The remaining eight patients had had a contraindication to anticoagulation, and three had experienced a hemorrhagic complication as a result of anticoagulation following either a recently documented deep venous thrombosis (n = 3) or pulmonary embolism (n = 5). Filters were successfully placed in all 13 patients, with a duration of implantation ranging from 2 to 15 days. Retrieval was attempted in 12 patients (in 1 patient, permanent filtration was secondarily requested) and was achieved in 10 (84.6%) patients. In 2 patients, retrieval failure was due to device angulation within the vena cava precluding safe retrieval. In both instances, the device used was the Gunther Tulip filter. No patient developed symptomatic pulmonary embolism or insertion-site thrombosis following either filter deployment or removal. Trapped thrombus in the filters was seen in all patients. Retrieval required a mean of 6.8 minutes (range 5-10.2 minutes) of fluoroscopy time. Neither filter migration nor caval injury was observed. Temporary IVC filters are effective and are associated with a high retrieval success rate. Further study is warranted to determine the maximal duration of implantation and whether retrievable IVC filters should expand the indications for IVC filter placement.