Percutaneous insertion of the Greenfield inferior vena cava filter: experience with ninety-six patients

This article evaluates the ease, safety, and convenience of percutaneous Greenfield filter placement and compares percutaneous with surgical placement. Greenfield filters were inserted percutaneously into the inferior vena cava in 96 patients. Ninety filters were placed via the femoral route and 12 were placed from the right internal jugular vein. Six patients had two filters inserted. An inferior venacavogram was performed before filter insertion in all patients. Cavography provided vital information concerning diameter of the inferior vena cava, the level of the renal veins, and the presence and location of thrombus. Filter placement was accomplished in all patients in whom it was attempted. There were four minor complications and one periprocedural death. The incidence of documented femoral vein thrombosis that could be related to percutaneous placement via the femoral veins was 33%; however, none of these patients had permanent venous stasis sequelae. Percutaneous insertion of the Greenfield filter is a safe and convenient procedure and is superior to surgical placement in terms of time, logistics, and the accuracy of filter positioning.     

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.     

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.     

Early duplex scan evaluation of four vena caval interruption devices

Purpose: Transvenous inferior vena cava (IVC) filters are used successfully for prevention of pulmonary embolism (PE), but early thrombotic complications such as insertion site thrombosis (IST) and inferior vena cava thrombosis (IVCT) may occur after placement. The frequency of these complications has been uncertain particularly for the wide variety of newer devices. This study was performed to prospectively evaluate IST and IVCT with color-flow venous duplex ultrasound scanning after four IVC filters were placed: the birds' nest filter, the titanium Greenfield filter, the stainless steel Greenfield filter, and the Simon nitinol filter.Methods: Percutaneous IVC filters were placed in 174 patients over a 21-month period. A birds' nest filter was used in 39 (22%) cases, a titanium Greenfield filter in 67 (39%) cases, a stainless steel Greenfield filter (25%) in 43 patients, and a Simon nitinol filter in 25 (14%) cases. Filters were placed for major deep venous thrombosis in 113 (63%) patients, after PE in 26 (15%) patients, and with prophylaxis in 35 (20%) patients. All patients had color-flow venous duplex ultrasound scanning of the insertion site and the inferior vena cava 7 to 10 days after placement or before discharge to document IST or VCT.Results: Early IST occurred in 43 (24.7%) cases, and early IVCT was observed in 20 (12%) cases in this series. No significant difference was found in the incidence of IST or IVCT among the four filter types used. The incidence of IVCT was significantly higher in patients having filters placed for PE. Men were more likely to receive a prophylactic filter than women in this study, but thrombotic complications were not related to patient sex. Thrombosis was seen with equal frequency at all insertion sites used. No patient died of PE after filter placement during the study period.Conclusions: The incidence of thrombotic complications for all devices was higher than has generally been reported. No IVC filter used in this study demonstrated superior performance with regard to these thrombotic complications. As vena cava interruption devices are developed or significantly modified, prospective objective analysis of associated thrombotic complications will allow logical selection for clinical use. (J Vasc Surg 1996;24:809-18.)     

Results of a multicenter study of the modified hook-titanium Greenfield filter

Initial efforts to modify the stainless steel Greenfield filter for percutaneous insertion led to development of a titanium Greenfield filter, which could be inserted by use of a 12F carrier. This device functioned well as a filter but had an unacceptable 30% rate of migration, tilting, and penetration. Therefore a titanium Greenfield filter with modified hooks was developed and has been tested in 186 patients at 10 institutions. Successful placement occurred in 181 (97%); placement of the remainder was precluded by unfavorable anatomy. A contraindication to anticoagulation was the most frequent indication for insertion (75%). All but two were inserted percutaneously, predominantly via the right femoral vein (70%). Initial incomplete opening was seen in four patients (2%), which was corrected by guide wire manipulation and asymmetry of the legs in 10 (5.4%). Insertion site hematoma occurred in one patient, and apical penetration of the cava during insertion occurred in a second patient. Both events were without sequelae. Follow-up examinations were performed at 30 days at which time 35 deaths had occurred. Recurrent embolism was suspected in six patients (3%) and two of three deaths were confirmed by autopsy. Filter movement greater than 9 mm was seen in 13 patients, (11%) and increase in base diameter greater than or equal to 5 mm was seen in 17 patients (14%). CT scanning showed evidence of caval penetration in only one patient (0.8%). Insertion site venous thrombosis was seen in 4/46 (8.7%) patients screened. The modified hook titanium Greenfield filter is inserted percutaneously or operatively through a sheath, eliminating concern for misplacement from premature discharge.(ABSTRACT TRUNCATED AT 250 WORDS)     

Extended indications for placement of an inferior vena cava filter

To study the morbidity and mortality rates after placement of an inferior vena cava filter and to define the appropriate indications for interruption of the inferior vena cava, the records of all patients who underwent insertion of a Greenfield filter during the decade January 1978 to December 1987 were reviewed. Patients were designated as having either a traditional or extended indication for placement of an inferior vena cava filter. Two hundred sixty inferior vena cava filters were placed in 264 attempts, with no deaths related to insertion of the filter. An extended indication was the primary reason for placement of the Greenfield filter in 66 (25%) of the patients. In patients with extended indications there were no cases of air embolism or filter misplacement and only three wound complications (4.5%). Pulmonary embolism after insertion of the inferior vena cava filter occurred in three patients (4.5%), with one fatality (1.5%). Inferior vena cava occlusion was documented in three cases (4.5%), and manifestations of the postphlebitic syndrome in early follow-up were present in two patients (3.0%). As the procedures to prevent fatal pulmonary embolism have become safer, more efficacious, and less morbid, the number of patients in whom the potential benefits of insertion of an inferior vena cava filter outweigh the risks has become larger. Our results support the liberalized use of Greenfield filters in those patients who do not necessarily have one of the traditional indications for placement of an inferior vena cava filter but are at a high risk of having a fatal pulmonary embolus.     

Long-term follow-up of Greenfield inferior vena cava filter placement in children.

OBJECTIVE: The long-term results of Greenfield inferior vena cava (IVC) filter placement have been well documented in adults; however, similar data do not exist for pediatric patients. The potential for growth and the increased life expectancy in younger patients may contribute to a difference in the natural history of filters placed in children. The objective of this study was to evaluate the long-term outcome of pediatric patients with IVC filters. METHODS: At the University of Massachusetts Memorial Medical Center, medical records and radiographs of patients 18 years old or younger at the time of IVC filter placement were reviewed. Follow-up data were obtained by interview, physical examination, and venous duplex ultrasound scanning. RESULTS: A total of 15 IVC filters were placed in children 18 years old or younger between 1983 and 1999. In 10 patients the indications for IVC filter placement were lower-extremity deep venous thrombosis (DVT) and/or pulmonary embolism. In five patients, prophylactic filters were placed in the absence of DVT because of a high risk for the development of pulmonary embolism. Surgical exposure of the right internal jugular vein was used to place the first eight filters. The remainder were inserted percutaneously through the right internal jugular vein or the right common femoral vein. There were no complications or mortality related to filter insertion. Follow-up of the surviving 14 patients ranged from 19 months to 16 years. During long-term follow-up, no patient had a pulmonary embolus. Of the nine patients who had lower-extremity DVT, three developed mild common femoral venous reflux documented by duplex scan. Of the five patients who had prophylactic filters, four had no symptoms or duplex evidence of reflux. The other patient, who was paraplegic, had bilateral leg edema but no venous varicosities and no reflux on duplex scan 11 years after filter placement. No patient in either group had chronic venous obstruction. CONCLUSION: In long-term follow-up there were no instances of pulmonary embolism, IVC thrombosis, significant postphlebitic symptoms, or significant filter migration among 14 pediatric patients with Greenfield IVC filters. This suggests a safety profile and efficacy similar to that seen in adults.     

Delayed retroperitoneal arterial hemorrhage after inferior vena cava (IVC) filter insertion: case report and literature review of caval perforations by IVC filters

Transvenous placement of inferior vena cava (IVC) filters has become commonplace in selected patients with deep venous thrombosis (DVT) and pulmonary embolism (PE). IVC filters have been shown to have excellent therapeutic efficacy and low complication rates. Penetration of the IVC by filter hooks or struts has been reported and commonly noted to be inconsequential. We report a laceration of a lumbar artery by a stainless steel Greenfield (SSG) filter strut that resulted in a near fatal hemorrhage, and review the world literature on caval perforation by IVC filters.     

Current use of inferior vena cava filters.

To study possible changes in the clinical use of inferior vena cava (IVC) filters caused by the introduction of percutaneous delivery systems, we reviewed all patients who underwent placement of IVC filters at our institution from 1988 to 1991. Eighty-four patients (52 men and 32 women) ranging in age from 18 to 90 years (mean 67 years) were identified. Filters were required because of contraindications to anticogulation in 64% anticoagulation failure in 25%, and preoperative prophylaxis in 11% of patients. The underlying disease was lower extremity deep vein thrombosis in 50% and pulmonary embolism in 45% of patients. Five percent of patients received prophylactic filters without documented thromboembolism. All filters were placed percutaneously by interventional radiologists, 77 through the common femoral vein and 7 through the internal jugular vein. Three types of filters were used. One procedure-related death occurred because of acute IVC occlusion. Fatal pulmonary embolism within 48 hours after filter placement was documented in one patient and suspected in one late death. No other clinically apparent pulmonary embolism or leg swelling occurred after filter placement. Minor complications related to filter placement occurred in 13 patients, but none required operative intervention. Analysis of complication rates of the three filter types was precluded by the small sample size. After a mean follow-up of 11 months, 42 patients (50%) had died of malignancy (n = 25), multisystem organ failure (MSOF; n = 7), cardiovascular events (n = 4), recurrent pulmonary embolism (n = 2), cerebrovascular events (n = 4), or an unknown cause (n = 1). Twenty-three patients (27%) died before hospital discharge.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term follow-up for superior vena cava filter placement

The short-term effectiveness and safety placement of superior vena cava (SVC) filter in the treatment of upper extremity deep venous thrombosis in patients with contraindication to anticoagulation have been well documented. However, as opposed to the numerous reported experiences with inferior vena cava filter placement and its complications, there has been no documented long-term follow-up on SVC filter placement. We, therefore, reviewed our experience with SVC filter placement. A retrospective review was performed of the 154 cases of patients who underwent SVC filter placement between January 1994 and August 2005 at our institution. Seven additional patients had unsuccessful SVC filter placement due to widespread deep venous thrombosis. The data were evaluated for both insertion complications (pneumothorax, hemorrhage, filter misplacement) and long-term complications (pulmonary embolism, migration, caval occlusion). The follow-up included review of serial chest radiographs to evaluate for filter migration in patients who lived at least 60 days after filter insertion and had chest radiography performed (n = 40), patients' charts, clinic visits, and telephone contacts, hospital databases, city death records, and national databases. There were 69 males and 85 females with a mean age of 73.6 years (range, 16-96 years; +/-15.3 [SD] years). Follow-up ranged from 1 day to 3750 days (256.3 +/- 576 days [mean +/- SD]) and 5 patients were lost to follow-up. Of the 154 patients, 58 survived longer than 60 days with mean follow-up of 628.4 days. All SVC filters (TrapEase, n = 38; Greenfield, n = 116) were successfully deployed in the 154 patients. During the follow-up, 114 (74.0% mortality) of the patients died of chronic illness or from cancer complications. There were three cases of pericardial tamponade (1.9%), and one case of misplaced filter in innominate vein. There were no known cases of symptomatic pulmonary embolism, caval occlusion, pneumothorax, or filter migration. SVC filter placement is associated with a low incidence of complications with long-term follow-up. These data help to reaffirm the safety and effectiveness of SVC filter placement. However, SVC perforation in young males remains a significant issue.     

Acute complications associated with greenfield filter insertion in high-risk trauma patients

BACKGROUND: Use of Greenfield filters (GFs) to prevent fatal pulmonary embolism (PE) in trauma patients is generally well accepted. Nonetheless, a surprisingly small number of trauma surgeons insert filters in their patients. Among the reasons cited is fear of complications. METHODS: We observed three femoral arteriovenous fistulae (AVF) in trauma patients who had inferior vena caval placement of filters for PE prophylaxis in one 12-month period (academic year 1999). In an effort to document the magnitude of this problem, we evaluated trauma patients who had a GF inserted in academic year 2000. RESULTS: During that year, 133 consecutive patients (8.6% of trauma admissions) received 133 GFs through a percutaneous approach. The most common isolated indications for GF insertion included closed head injuries (n = 28), multiple long bone fractures (n = 27), pelvic and acetabular fractures (n = 6), spinal cord injuries (n = 16), and vertebral fractures (n = 3). Five patients had documented deep venous thrombosis (DVT) diagnosed by duplex ultrasonography before GF placement, and 11 patients had other indications requiring a filter. There were 37 patients with more than one indication requiring filter placement. Most patients (57%) underwent preinsertion duplex scanning of their lower extremity veins; 77% of patients underwent postinsertion scanning. Filters were inserted an average of 6.8 +/- 0.6 (SE) days after trauma. No AVF were suspected clinically or detected ultrasonographically. No operative or postoperative complications occurred. DVT was observed in 30% of patients despite 92% prophylaxis; there was a 26% incidence of de novo thrombi detected. None of the patients evidenced DVT clinically. CONCLUSION: Our data indicate that complications of GF insertion for prophylaxis against PE from DVT complicating trauma patients continue to be negligible. In addition, the incidence of insertion-site thrombosis may be lower than expected. Moreover, femoral AVF is a rare complication of this procedure.     

Duplex scan-directed placement of inferior vena cava filters: a five-year institutional experience

PURPOSE: The purpose of this study was the assessment of the safety, efficacy, and hospital charges of bedside duplex ultrasound-directed inferior vena cava (IVC) filter placement. METHODS: All duplex ultrasound-directed IVC filters that were placed from August 8, 1995, to December 31, 2000, are reviewed. Chart review combined with mailed questionnaires and telephone follow-up examinations were used to collect demographic and outcome data. RESULTS: Three hundred twenty-five patients underwent evaluation, and 284 underwent duplex ultrasound-directed IVC filter placement. Two hundred three (71%) were male patients, and 81 (29%) were female patients. Poor IVC visualization, IVC thrombosis, and unsuitable anatomy prevented duplex-directed filter placement in 41 patients (12%). Indication for filter placement included venous prophylaxis in the absence of thromboembolism in 235 patients (83%), contraindication to anticoagulation therapy in 34 patients (12%), prophylaxis with therapeutic anticoagulation therapy in the presence of thromboembolism in 7 patients (2%), and complication of anticoagulation therapy in 8 patients (3%). There were no procedure-related deaths or septic complications. Technical complications occurred in 12 patients (4%). Filter misplacement occurred in 6 patients (2%), access thrombosis in 1 (<1%), migration in 1 (<1%), bleeding in 1 (<1%), and IVC occlusion in 3 (1%). Pulmonary emboli after IVC filter placement occurred in one patient with a misplaced filter. Average hospital charges related to duplex ultrasound-directed filter placement were $2388 less than fluoroscopic placement charges in the year 2000. CONCLUSION: Our experience indicates that duplex ultrasound-directed IVC filter placement is safe, cost-effective, and convenient for patients who need IVC filter placement.     

Thromboembolism: prevention and treatment with vena cava filters

Mechanical approaches to the prevention of pulmonary thromboembolism have evolved from direct operative procedures to the percutaneous insertion of a variety of filter devices. The longest follow-up experience is with the Greenfield vena caval filter (Medi-Tech, Inc, Watertown, MA), which has a long-term vena caval patency rate of 98% and a recurrent embolism rate of 4%. Alternative filters, such as the Bird's Nest (Cook, Inc, Bloomington, IN), VenaTech (VenaTech, Evanston, IL), and Simon Nitinol (Nitinol Medical Technologies, Woburn, MA), are effective in the prevention of embolism but have a vena caval thrombosis rate of 8% to 20%. The efficacy and safety of prophylactic insertion of the Greenfield filter has been demonstrated in several clinical trials, which appears to justify its use in appropriately selected high-risk patients scheduled for orthopedic procedures.     

Suprarenal filter placement

Purpose: This study was undertaken to determine the clinical outcomes for patients with Greenfield filters placed in the suprarenal (SR) inferior vena cava (IVC). Methods: We collected data prospectively from annual follow-up evaluations of patients with filters. Patients underwent venous color-flow duplex examinations of the IVC and lower extremities, abdominal radiographs, and physical assessment. The outcomes for those patients with filters in the SR IVC were compared with the outcomes previously reported and with the outcomes for patients with filters in the infrarenal cava. Results: SR placement accounted for 7.6% (148/1932) of all filter placements. Follow-up data were available for 73 placements, or 49%. No cases of renal dysfunction were related to filter placement. The rate of recurrent pulmonary embolism (PE) was 8%, and the rate of long-term caval occlusion was 2.7%. These rates did not differ statistically from the rates for patients with infrarenal filters (P > .05). Male patients tended to be older by 15 years, to have more recurrent PE, and to experience more filter migration (6 vs 2 mm). Failure of SR filters to prevent PE was associated statistically with the primary indication for placement. Recurrent PE was the indication in 5 of 6 patients who sustained PE after SR filter placement (P = .007). Filter limb fracture was seen only with the stainless-steel Greenfield filter. Conclusion: Greenfield filters placed above the renal vein provide protection from PE with a minimal risk of occlusion. Twenty-five years of experience with Greenfield filters shows that they are safe and effective both in young female patients of child-bearing potential and in all patients with appropriate indications for SR placement. (J Vasc Surg 1998;28:432-8.)     

Vena caval filter use in patients with sepsis: results in 175 patients

BACKGROUND: Septic patients are at risk of thromboembolism. However, the Food and Drug Administration guidance for intravascular filters states that "filters should not be implanted in patients with risk of septic embolism." The purpose of this study is to evaluate this restriction. HYPOTHESIS: There is no difference in outcomes following filter placement in patients with and without septicemia. DATA SOURCES: A registry of vena caval filter experiences containing information regarding filter placement and annual examinations of more than 2600 patients obtained during a 15-year period was reviewed. We conducted a MEDLINE search of publications reporting clinical sequelae of filter placement in septic patients. DATA EXTRACTION: The registry was searched for patients with a diagnosis of sepsis at filter placement; survival rates, adverse events, and recurrent sepsis or thromboembolism were noted. The MEDLINE search joined results from 7 MeSH headings (vena cava filter,sepsis, septic thromboembolism, vena caval filter contraindication, and filter adverse events) related to filters and sepsis. DATA SYNTHESIS: One-hundred seventy-five patients (6.7%) met the criteria and received Greenfield filters. None of the adverse events were related to sepsis, and no filter was removed. Follow-up data were available for 56 patients, with a combined recurrent pulmonary embolism and caval occlusion rate of 1.7%. The 30-day mortality rate was 33%. We noted a significant difference in survival related to the use of anticoagulation therapy (P =.001) and to age (P =.004). The MEDLINE search did not identify any clinical reports of septic filters or the need to remove a filter because of sepsis. CONCLUSIONS: Based on our review, the Greenfield filter is a safe method of prophylaxis for septic patients. Rescinding the restriction for use of vena caval filters in septic patients should be considered by regulatory bodies.     

The percutaneous greenfield filter: outcomes and practice patterns

OBJECTIVE: The percutaneous steel Greenfield filter (PSGF) is similar in appearance to the titanium Greenfield filter (TGF) but differs in the length and orientation of the attachment hooks and in the over-the-wire delivery system. Because these differences improve ease of insertion and attachment, they may affect patient outcomes and physician practices. The purpose of this study was to evaluate the performance of the PSGF relative to the TGF and to determine whether there had been a change in physician practices. METHODS: The Michigan Filter Registry contains data for a prospective cohort of 2188 patients with Greenfield filters. Procedural and long-term outcomes for patients with a PSGF were abstracted. These events were compared with rates for Registry patients who had a TGF. Trends for indication for placement, delivery route, and filter location were also compared with published series. RESULTS: Since 1995, 600 PSGFs have been placed in 599 patients. A 1-year mortality rate of 42% left 349 patients available for annual follow-up, and studies were completed for 231 (66%). Periprocedural events occurred in 2.5% of cases with associated morbidity in 1.5%. The rate of new pulmonary embolism was 2.6%, and vena caval patency was 98.3%. The combined rate of new venous thromboembolic events was 12.5%. Left-sided femoral vein placements increased to 20%, and the major indication for filter placement has become prophylaxis (46%). CONCLUSIONS: The PSGF is similar to the TGF with respect to patient outcomes, and it provides decreased rates of asymmetry along with excellent fixation. The flexible carrier system has allowed more frequent access through the left femoral vein. The ease of use and favorable patient outcomes have resulted in more frequent placement for prophylactic indications.     

Intraoperative insertion of Greenfield filters: lessons learned in a personal series of 152 cases

The objective of this study was to define outcomes of 151 patients who underwent insertion of 152 Greenfield filters in the operating room by general and vascular surgery residents with supervision by one attending vascular surgeon. Each patient was taken to the operating room for inferior vena cava (IVC) interruption immediately after a vena cavagram was performed. One patient required a subsequent return to the operating room after developing paradoxical arterial embolism from a large venous thromboembolism which was trapped by and spanned both sides of the first IVC filter. In this case a second suprarenal filter was placed at the time of arterial embolectomy. In each of these 152 cases intraoperative venacavography was performed using a mobile C-arm. Complications such as hemothorax, filter misplacement, and vena cava perforation were identified. Late survival was defined using the Social Security Death Index. Of the 151 patients undergoing intraoperative insertion of Greenfield filters there was one hemothorax from attempts at acquiring venous access via percutaneous puncture of the internal jugular vein. This required transfusion but not thoracotomy, and IVC interruption was achieved. A separate patient had insertion of a Greenfield filter into a gonadal vein which required placement of a second filter into the IVC. There was one IVC perforation from a transfemoral filter insertion which required placement of a second filter above this perforation and laparotomy to retrieve the filter and repair the IVC. In one more patient the IVC filter initially failed to open, and a second filter was placed above the first filter. In this experience the misplacement rate was 0.7 per cent and the serious complication rate was 1.3 per cent. None of the patients was adversely affected per se by transfer to the operating room for Greenfield filter insertion. No patient died from filter insertion, but in two cases serious associated complications contributed to the adverse outcomes in these already terminally ill patients. Overall 30-day mortality rate was 6.6 per cent. Late survival was defined as follows: survival at one year after filter insertion was 75 per cent, at 2 years 63 per cent, at 3 years 60 per cent, at 4 years 57 per cent, and at 5 years 54 per cent. Mean survival after filter placement was 4.96 years. We conclude that Greenfield filters can be inserted in the operating room by general and vascular surgery residents with attending supervision with reasonable safety and with a low rate of filter misplacement. The caval perforation and gonadal vein filter misplacement could both have been avoided by use of an over-the-wire filter deployment system, which at the time of these specific complications was not available. Vena cava filter insertion should remain within the scope of practice of surgeons and can be done with reasonable safety under C-arm guidance in the operating room. Use of over-the-wire systems could have helped reduce the likelihood of all but one of the filter-related complications experienced in this series.     

Use of the Greenfield filter in adolescents for deep vein thrombosis and pulmonary embolism

Serious venous thromboembolic disease is now recognized more frequently in the pediatric age group. Caval interruption is indicated most commonly for prophylaxis against life-threatening or recurrent pulmonary embolism (PE) when anticoagulation is ineffective or contraindicated. Greenfield vena caval filters have been utilized locally in 415 adult patients with 97% long-term patency and 5% recurrent embolization. Its application in adolescents is reported herein. Standard adult (30-mm) vena caval filters were placed in ten patients, ages 13 to 18. Four filters were required following PE, six were used for deep venous thrombosis (DVT) when anticoagulation was contraindicated, and one was inserted prophylactically. In eight patients, filter insertion was accomplished with local anesthesia, while two underwent filter placement under general anesthesia administered for other procedures. One filter was misplaced into the right renal vein, requiring a second filter insertion. All patients have been followed from 1 to 11 years with yearly vascular duplex imaging and radionuclide venograms documenting caval patency without clinical embolic sequelae. This duplicates the adult experience in safety and efficacy. As recognition of venous thromboembolism becomes more frequent in the pediatric age group, safe caval interruption may be necessary for those excluded from or not responsive to anticoagulation. This technique may be extended to smaller patients with miniaturization of both filter and carrier.     

Clinical outcome and complications of temporary inferior vena cava filter placement

OBJECTIVE: We evaluated the current clinical experience of temporary inferior vena cava (IVC) filter placement and its related complications. METHODS: From January 2000 to December 2005, we enrolled 33 patients (8 men and 25 women) who underwent percutaneous insertion of a temporary IVC filter in the Department of Vascular Surgery of Tokyo University Hospital. Deep vein thrombosis (DVT) was proven in 78.8% of the patients. The indications for filter insertion were contraindication to anticoagulation therapy (9.1%), thrombolytic therapy (12.1%), perioperative prophylactic implantation (84.8%), pregnancy with DVT (3.0%), and prophylactic implantation in the absence of DVT (15.2%). A Neuhaus Protect was used in 13 patients, and an Antheor was used in 20 patients. RESULTS: The mean +/- SD duration of filter placement was 10.6 +/- 7.0 days. There was no case of pulmonary embolism during filter protection and retraction. Filter thrombosis (capture of thrombus) was observed in four patients (12.1%), who then received additional thrombolytic therapy. Thrombi were dissolved by thrombolysis in three, one of whom had replacement with a permanent filter. The thrombus was not dissolved in one patient and was removed under venotomy at the insertion site. Major filter-related complications occurred in nine patients (27.3%), including filter dislocation in four patients (12.1%), catheter fracture in three (9.1%), and catheter-related infection in one (3.0%). In a patient with giant ovarian cancer, the IVC was nearly occluded with massive thrombus around the filter 2 days after operation, and the vena cava was then ligated under open laparotomy. No patients died during filter protection and retraction. CONCLUSIONS: Temporary IVC filters were effective for the prevention of fatal pulmonary embolism. However, our experience of a high incidence of complications related to temporary filters suggests that this device has limited indications and supports the need for innovative design of temporary filters.     

Duplex ultrasound insertion of inferior vena cava filters in multitrauma patients.

BACKGROUND: Techniques for placement of inferior vena cava (IVC) filters have undergone continued evolution from open surgical exposure of the venous insertion site to percutaneous insertion in most cases today. However, the required transport either to an operating room or interventional suite can be complex and potentially hazardous for the multiply injured trauma patient who may require ventilator support, controlled intravenous infusions, or skeletal immobilization. Increased experience with color-flow duplex scanning for routine IVC imaging and portability of ultrasound equipment have suggested the usefulness of duplex-guided IVC filter insertion (DGFI) in critically ill trauma and intensive care unit (ICU) patients. METHODS: A total of 25 multitrauma/ICU patients were considered for DGIF. Screening color-flow duplex scans were performed on all patients, and obesity or bowel gas prevented ultrasound imaging in 2 cases, leaving 23 patients suitable for DGFI. In each case, the IVC was imaged in the transverse and longitudinal planes. The right renal artery was identified as it passed posterior to the IVC and was used as a landmark of the infrarenal segment of the IVC. All procedures were performed at the bedside in a monitored ICU setting using percutaneous placement of titanium Greenfield filters. Duplex scanning after insertion was used to document proper placement, and circumferential engagement of the filter struts in the IVC wall. An abdominal radiograph was also obtained in each case to confirm proper filter location. Duplex ultrasound imaging was repeated within 1 week of insertion to assess IVC and insertion site patency. RESULTS: DGFI was successful in all cases. The filter was deployed at a suprarenal level in one case, as was recognized at the time of postprocedural scanning. Three patients died as a result of their injuries but there were no pulmonary embolism deaths. Repeat duplex scanning was obtained in 17 patients, and revealed no case of IVC or insertion site thrombosis. CONCLUSIONS: Vena caval interruption can be safely performed under ultrasound guidance in a monitored, ICU environment. In selected multiply injured trauma patients, this will reduce the risk, complexity and cost of transport for these critically ill patients. DGFI also reduces procedural costs compared with an operating room or interventional suite, and eliminates intravenous contrast exposure. Preprocedural scanning is essential to identify patients suitable for DGFI, and careful attention must be paid to the known ultrasonographic anatomical landmarks.