Retrievable vena cava filters

Application of Deep Learning to IVC Filter Detection from CT Scans

IVC filters (IVCF) perform an important function in select patients that have venous blood clots. However, they are usually intended to be temporary, and significant delay in removal can have negative health consequences for the patient. Currently, all Interventional Radiology (IR) practices are tasked with tracking patients in whom IVCF are placed. Due to their small size and location deep within the abdomen it is common for patients to forget that they have an IVCF. Therefore, there is a significant delay for a new healthcare provider to become aware of the presence of a filter. Patients may have an abdominopelvic CT scan for many reasons and, fortunately, IVCF are clearly visible on these scans. In this research a deep learning model capable of segmenting IVCF from CT scan slices along the axial plane is developed. The model achieved a Dice score of 0.82 for training over 372 CT scan slices. The segmentation model is then integrated with a prediction algorithm capable of flagging an entire CT scan as having IVCF. The prediction algorithm utilizing the segmentation model achieved a 92.22% accuracy at detecting IVCF in the scans.

State-Level Variation in Inferior Vena Cava Filter Utilization Across Medicare and Commercially Insured Populations

OBJECTIVE. Recent research on inferior vena cava (IVC) filter utilization in the United States has largely focused on national aggregate Medicare datasets, showing recent declines. Whether these national Medicare trends are generalizable across regions and payer populations is unknown. We studied recent state-level variation in IVC filter utilization across both Medicare and private insurance populations. MATERIALS AND METHODS. Using large individual beneficiary claims-level Medicare research identifiable files and a proprietary U.S. research database of the commercially insured population, we identified all billed IVC filter placement procedures performed between 2009 and 2015. We compared population-adjusted utilization rates by state and payer type. RESULTS. Between 2009 and 2015, IVC filter utilization across the United States declined by 36.3% (from 177.9 to 113.3 procedures per 100,000 beneficiaries) in the Medicare population and by 26.6% (from 32.7 to 24.0 procedures per 100,000 beneficiaries) in the privately insured population. For the Medicare population, state-level utilization rates varied 5.2-fold, from 48.4 to 251.3 procedures per 100,000 beneficiaries in Alaska and New Jersey, respectively. For the private insurance population, rates varied 5.5-fold, from 10.8 to 59.5 procedures per 100,000 beneficiaries in Oregon and Michigan, respectively. Nationally, utilization in the Medicare population was 5.0 times higher than that in the private insurance population (range by state, from 2.0 times higher in Hawaii to 11.1 times higher in Utah). Despite the national decline, utilization in Medicare and private insurance populations increased in five and seven states, respectively. State-level IVC filter utilization rates for the Medicare population correlated strongly with those for the privately insured population (r = 0.74; p < 0.001). In both the Medicare and privately insured populations, utilization rates correlated moderately with beneficiary age (r = 0.44 and r = 0.50, respectively; p < 0.001 for both). CONCLUSION. IVC filter utilization rates vary dramatically by state and payer population, and they likely depend in part on the age of the covered population. To better identify demographic and socioeconomic drivers of utilization, future research should prioritize nonaggregate multipayer claims-level approaches.

Trends in vena cava filter insertions and "prophylactic" use

BACKGROUND

Prophylactic vena cava filter (VCF) use in patients without venous thromboembolism is common practice despite ongoing controversy. Thorough analysis of the evolution of this practice is lacking. We describe trends in VCF use and identify events associated with changes in practice.

METHODS

Using the National Inpatient Sample, we conducted a retrospective observational study of U.S. adult hospitalizations from 2000 to 2014. Trends in prophylactic VCF insertion were analyzed both across the entire study population and within subgroups according to trauma status and type of concurrent surgery. Annual percentage change (APC) was calculated, and trends were analyzed using Poisson regression.

RESULTS

Among 461,904,314 adult inpatients (median [interquartile range] age, 58.1 [38.5-74.3] years; 39.6% male), the incidence of VCF insertion increased rapidly at first (from 0.19% to 0.35%; APC, 11.2%; 95% confidence interval [CI], 10.3%-12.2%; P < .001), then at a slower rate after the publication of the Prévention du Risque d'Embolie Pulmonaire par Interruption Cave 2 (PREPIC2) trial in 2005 (from 0.35% to 0.42%; APC, 4.4%; 95% CI, 2.8%-6.0%; P < .001), and it began decreasing after the 2010 Food and Drug Administration (FDA) safety alert (from 0.42% to 0.32%; APC, -5.5%; 95% CI, -6.5% to -4.6%; P < .001). The percentage of total VCFs that had a prophylactic indication increased quickly before publication of the PREPIC2 trial (APC, 19.5%; 95% CI, 17.9%-21.0%; P < .001), increased at a slower rate after publication in 2005 (APC, 4.4%; 95% CI, 2.6%-6.2%; P < .001), and dropped after the FDA safety alert, stabilizing at 18.5% for the last 3 years (APC, -0.3%; 95% CI, -2.2% to 1.7%; P = .8). Subgroups most associated with prophylactic VCF insertion were operative trauma (odds ratio [OR], 10.9; 95% CI, 10.2-11.7), orthopedic surgery (OR, 4.7; 95% CI, 4.3-5.2), and neurosurgical procedures (OR, 3.9; 95% CI, 3.6-4.2). All groups except orthopedic surgery experienced a deceleration in prophylactic VCF growth after the publication of PREPIC2. Meanwhile, the FDA safety alert was associated with a decrease in prophylactic VCF insertions for all groups except other major surgery.

CONCLUSIONS

Whereas publication of the PREPIC2 trial led to a deceleration in prophylactic VCF insertion growth, the FDA alert had a bigger impact, leading to declining rates of prophylactic VCF use. Further investigations of prophylactic insertion of VCF in trauma, orthopedic, and neurosurgical patients are needed to determine whether current levels of use are justified.

Vena Cava Filter Use in Trauma and Rates of Pulmonary Embolism, 2003-2015

Importance

Vena cava filter (VCF) placement for pulmonary embolism (PE) prophylaxis in trauma is controversial. Limited research exists detailing trends in VCF use and occurrence of PE over time.

Objective

To analyze state and nationwide temporal trends in VCF placement and PE occurrence from 2003 to 2015 using available data sets.

Design, Setting, and Participants

A retrospective trauma cohort study was conducted using data from the Pennsylvania Trauma Outcome Study (PTOS) (461 974 patients from 2003 to 2015), the National Trauma Data Bank (NTDB) (5 755 095 patients from 2003 to 2014), and the National (Nationwide) Inpatient Sample (NIS) (24 449 476 patients from 2003 to 2013) databases.

Main Outcomes and Measures

Temporal trends in VCF placement and PE rates, filter type (prophylactic or therapeutic), and established predictors of PE (obesity, pregnancy, cancer, deep vein thrombosis, major procedure, spinal cord paralysis, venous injury, lower extremity fracture, pelvic fracture, central line, intracranial hemorrhage, and blood transfusion). Prophylactic filters were defined as VCFs placed before or without an existing PE, while therapeutic filters were defined as VCFs placed after a PE.

Results

Of the 461 974 patients in PTOS, the mean (SD) age was 47.2 (26.4) and 61.6% (284 621) were men; of the 5 755 095 patients in NTDB, the mean age (SD) was 42.0 (24.3) and 63.7% (3 666 504) were men; and of the 24 449 476 patients in NIS, the mean (SD) age was 58.0 (25.2) and 49.7% (12 160 231) were men. Of patients receiving a filter (11 405 in the PTOS, 71 029 in the NTDB, and 189 957 in the NIS), most were prophylactic VCFs (93.6% in the PTOS, 93.5% in the NTDB, and 93.3% in the NIS). Unadjusted and adjusted temporal trends for the PTOS and NTDB showed initial increases in filter placement followed by significant declines (unadjusted reductions in VCF placement rates, 76.8% in the PTOS and 53.3% in the NTDB). The NIS demonstrated a similar unadjusted trend, with a slight increase and modest decline (22.2%) in VCF placement rates over time; however, adjusted trends showed a slight but significant increase in filter rates. Adjusted PE rates for the PTOS and NTDB showed significant initial increases followed by slight decreases, with limited variation during the declining filter use periods. The NIS showed an initial increase in PE rates followed by a period of stagnation.

Conclusions and Relevance

Despite a precipitous decline of VCF use in trauma, PE rates remained unchanged during this period. Taking this association into consideration, VCFs may have limited utility in influencing rates of PE. More judicious identification of at-risk patients is warranted to determine individuals who would most benefit from a VCF.

Inferior vena cava filters

Use of inferior vena cava (IVC) filters has increased dramatically in recent decades, despite a lack of evidence that their use has impacted venous thromboembolism (VTE)-related mortality. This increased use appears to be primarily driven by the insertion of retrievable filters for prophylactic indications. A growing body of evidence, however, suggests that IVC filters are frequently associated with clinically important adverse events, prompting a closer look at their role. We sought to narratively review the current evidence on the efficacy and safety of IVC filter placements. Inferior vena cava filters remain the only treatment option for patients with an acute (within 2-4 weeks) proximal deep vein thrombosis (DVT) or pulmonary embolism and an absolute contraindication to anticoagulation. In such patients, anticoagulation should be resumed and IVC filters removed as soon as the contraindication has passed. For all other indications, there is insufficient evidence to support the use of IVC filters and high-quality trials are required. In patients where an IVC filter remains, regular follow-up to reassess removal and screen for filter-related complications should occur.

Optional Vena Cava Filters: What, Why, and When

Optional vena cava filters can used to provide either short-term or permanent protection from pulmonary embolism. These devices have recently become available for clinical use in the United States. However, there remains a paucity of data about these devices and their outcomes. This article reviews current and future devices, the rationale behind non-permanent caval filtration, and the generally accepted guidelines for their clinical application.

A Critical Review of Available Retrievable Inferior Vena Cava Filters and Future Directions

Inferior vena cava filters have been placed in patients for decades for protection against pulmonary embolism. The widespread use of filters has dramatically increased owing at least in part to the approval of retrievable vena cava filters. Retrievable filters have the potential to protect against pulmonary embolism and then be retrieved once no longer needed to avoid potential long-term complications. There are several retrievable vena cava filters available for use. This article discusses the different filter designs as well as the published data on these available filters. When selecting a filter for use, it is important to consider the potential short-term complications and the filters' window for retrieval. Understanding potential long-term complications is also critical, as these devices are approved for permanent placement and many filters are not retrieved. Finally, this article will address research into new designs that may be the future of vena cava filtration.

Caval filters in intensive care: a retrospective study

AIM

To evaluate the effectiveness of a caval vein filter (CVF) peri-implant monitoring protocol in order to reduce pulmonary embolism (PE) mortality and CVF-related morbidity.

BACKGROUND

The reduction in mortality from PE associated with the use of CVF is affected by the risk of increase in morbidity. Therefore, CVF implant is a challenging prophylactic or therapeutic option. Nowadays, we have many different devices whose rational use, by applying a strict peri-implant monitoring protocol, could be safe and effective.

MATERIALS AND METHODS

We retrospectively studied 62 patients of a general Intensive Care Unit (ICU) scheduled for definitive, temporary, or optional bedside CVF implant. A peri-implant monitoring protocol including a phlebocavography, an echo-Doppler examination, and coagulation tests was adopted.

RESULTS

In our study, no thromboembolic recurrence was registered. We implanted 48 retrievable and only 20 definitive CVFs. Endothelial adhesion (18%), residual clot (5%), cranial or caudal migration (6%), microbial colonization of the filter in the absence of clinical signs of infection (1%), caval thrombosis (1%), and pneumothorax (1%) were reported. Deep-vein thrombosis (DVT) was reported (8%) as early complication. All patients with DVT had a temporary or optional filter implanted. However, in our cohort, definitive CVFs were reserved only to 32% of patients and they were not associated with DVT as complication.

CONCLUSION

CVF significantly reduces iatrogenic PE without affecting mortality. Generally, ICU patients have a transitory thromboembolic risk, and so the temporary CVF has been proved to be a first-line option to our cohort. A careful monitoring may contribute to a satisfactory outcome in order to promote CVF implant as a safe prophylaxis option.

The DENALI Trial: an interim analysis of a prospective, multicenter study of the Denali retrievable inferior vena cava filter

PURPOSE

To assess safety and effectiveness of a nitinol retrievable inferior vena cava (IVC) filter in patients who require caval interruption to protect against pulmonary embolism (PE).

MATERIALS AND METHODS

Two hundred patients with temporary indications for an IVC filter were enrolled in this prospective, multicenter clinical study. Patients undergoing filter implantation were to be followed for 2 years or for 30 days after filter retrieval. At the time of the present interim report, all 200 patients had been enrolled in the study, and 160 had undergone a retrieval attempt or been followed to 6 months with their filter in place. Primary study endpoints included technical and clinical success of filter placement and retrieval. Patients were also evaluated for recurrent PE, new or worsening deep vein thrombosis, and filter migration, fracture, penetration, and tilt.

RESULTS

Clinical success of placement was achieved in 94.5% of patients (172 of 182), with a one-sided lower limit of the 95% confidence interval of 90.1%. Technical success rate of filter placement was 99.5%. Technical success rate of retrieval was 97.3%; 108 filters were retrieved in 111 attempts. In two cases, the filter apex could not be engaged with a snare, and one device was engaged but could not be removed. Filter retrievals occurred at a mean indwell time of 165 days (range, 5-632 d). There were no instances of filter fracture, migration, or tilt greater than 15° at the time of retrieval or 6-month follow-up.

CONCLUSIONS

In this interim report, the nitinol retrievable IVC filter provided protection against pulmonary embolism, and the device could be retrieved with a low rate of complications.

The use of retrievable inferior vena cava filters in the trauma population

OBJECTIVE

To determine if the use of retrievable filters resulted in an increase in the placement of inferior vena cava (IVC) filters in trauma patients.

DESIGN

All patients who underwent IVC filter placement at Yale-New Haven Hospital, New Haven, Connecticut, USA between the years 1999 and 2004.

SETTING

Academic, level 1 trauma centre.

PATIENTS

Included in the present study were 202 trauma patients and 676 nontrauma patients.

INTERVENTION

IVC filter placement.

MAIN OUTCOME MEASURE

Demographics, indications, complication rates and type of IVC filters placed in trauma patients versus nontrauma patients were evaluated.

RESULTS

The present study determined 45.4% (n=92) of trauma patients undergoing IVC filter placement were younger than 40 years of age, compared with 7.8% (n=53) of nontrauma patients. The most common indication for IVC filter placement in trauma patients was prophylaxis (n=162, 80.2%), while in the nontrauma patients only 11.4% (n=77) of patients underwent prophylactic filter placement. The number of retrievable filters used in trauma patients increased from 46.7% in 2001, the year they became available, to 78.9% in 2004. The use of retrievable filters similarly increased in the nontrauma population from 35.9% in 2001 to 78.3% in 2004. Approximately 24% of the patients that underwent IVC filter placement at Yale-New Haven Hospital were categorized as trauma patients. The complication rate for this time period was 0.5% (n=1) in the trauma population versus 3.7% (n=26) in the nontrauma population.

CONCLUSION

The overall number of IVC filters placed in trauma patients did not dramatically increase with the introduction of retrievable filters, suggesting that the indications for the use of IVC filters have not changed.

Changing Patterns in the Use of Inferior Vena Cava Filters: Review of a Single Center Experience

BACKGROUND

The aim of this study was to review a Level I trauma center's pattern of use of IVC filters over a 6-year period.

STUDY DESIGN

During the years 1999 to 2004, 878 patients underwent placement of an IVC filter at our institution. We reviewed patient charts and collected data pertaining to patient demographics, types of filters, indication for placement, modes of venous access, and complication rates.

RESULTS

Our institution demonstrated an increase in prophylactic filter placement and the use of retrievable IVC filters. There was also an increasing trend in obtaining venous access through the jugular vein during filter placement.

CONCLUSIONS

IVC filters have proved safe and effective in preventing pulmonary embolism when used in a properly selected group of patients. With the introduction of new technology, such as retrievable IVC filters, ongoing efforts must be undertaken to define the indications for placement, duration of therapy, and the suitability of patients for the procedure.

Venous thromboembolism in trauma: an update for the intensive care unit practitioner

Venous thromboembolism (VTE) in trauma patients is a capricious problem that continues to plague trauma surgeons and critical care physicians alike. Pharmacologic preventions of VTE with anticoagulants are often contraindicated in the trauma patient because of risk of bleeding diathesis. Mechanical prophylaxis in the form of venous compression boots often cannot be placed because of external fixators, swelling, and so forth. Providing effective VTE prophylaxis, while at the same time providing definitive care for the trauma patient, can be a nightmare. This review will first discuss the incidence and prevalence of VTE, as well as investigate the condition's diagnosis and treatment. Solutions to frequently encountered clinical dilemmas in managing VTE in trauma patients are considered in the form of frequently asked questions. Diagnostic techniques such as magnetic resonance venography, D-dimer, and various computed tomography methods are evaluated. Recent literature on preventive pharmacologic therapies is explored. The authors also consider whether vena cava filters prevent pulmonary embolism in trauma patients.

Safety and efficacy of vena cava filters in trauma patients

Pulmonary embolism (PE), due to its sudden onset, notoriously difficult diagnosis, unpredictable nature and often fatal outcome, remains one of the most feared complications in surgical practice. Trauma patients with multisystem injuries, extremity or pelvic fractures and head or spinal cord injuries often pose a significant dilemma for the surgeon because of the inability to use conventional measures such as anticoagulation therapy and compression devices. On the other hand, the incidence of deep vein thrombosis (DVT) is high among trauma patients and the attendant risk of PE is an important cause of morbidity and mortality. Inferior vena cava (IVC) interruption by placement of diverse filtering devices has evolved over the past three decades. With the use of these devices, the risk of PE has been reduced dramatically. However, variable rates of complications are reported from their use. In this study, we review all the available data on IVC filter placement in trauma patients and we discuss the potential complications of IVC filters in order to understand better the risk/benefit ratio of their use.

Timing of Pulmonary Emboli after Trauma: Implications for Retrievable Vena Cava Filters

BACKGROUND

Four recent reports of the retrieval of optional vena cava filters (VCF) in trauma patients had average implant durations of 10, 19, and 19 days (one not specified). Two patients in these studies had pulmonary emboli after VCF removal. No evidence-based guidelines exist on the appropriate time to remove optional VCF. The purpose of this study was to examine the timing of pulmonary emboli (PE) and determine the optimal time to remove optional VCFs.

METHODS

A multicenter retrospective chart review of trauma patients who had a postinjury PE between January 2001 and December 2004 was performed. We examined the demographics, prophylaxis at the time of PE (pharmacologic [unfractionated or low molecular weight heparin] or sequential compression devices [SCD]), diagnostic test used, timing of PE from the date of injury, and survival outcome.

RESULTS

In all, 146 patients were identified, mean age 45.1 (+/- 21.1 SD); Injury Severity Score 18.0 (+/- 12.1 SD). Diagnosis was obtained by spiral computed tomography (N = 93), pulmonary arteriogram (N = 18), V/Q (N = 26), autopsy (N = 6), clinical (N = 6), and unknown (N = 3). Overall mortality was 17.8% (N = 26). Pulmonary embolism was felt to contribute to or was the cause of death in 85% (N = 22) of these patients. Two late PE deaths occurred (days 21 and 43). Sixty (37%) patients had pharmacologic prophylaxis at the time of PE and 83 (50.9%) had SCDs. Average time from injury to PE was 7.9 days (+/- 8.1 SD), the longest being 43 days postinjury. Eleven percent of PE occurred after 21 days, including fatal PE.

CONCLUSIONS

Clinical criteria defining the time to remove optional VCFs without exposing patients to the risk of PE by removing a filter too soon should be determined.

“Recovery™” Vena Cava Filter: Experience in 96 Patients

The purpose of the study was to assess the clinical safety and efficacy of the "Recovery(TM)" (Bard) inferior vena cava (IVC) filter. We retrospectively evaluated the clinical and imaging data of patients who had a "Recovery(TM)" IVC filter placed between January 2003 and December 2004 in our institution. The clinical presentation, indications, and procedure-related complications during placement and retrieval were evaluated. Follow-up computed tomography (CT) examinations of the abdomen and chest were evaluated for filter-related complications and pulmonary embolism (PE), respectively. "Recovery" filters were placed in 96 patients (72 males and 24 females; age range: 16-87 years; mean: 46 years). Twenty-four patients presented with PE, 13 with deep vein thrombosis (DVT) and 2 with both PE and DVT. The remaining 57 patients had no symptoms of thromboembolism. Indications for filter placement included contraindication to anticoagulation (n = 27), complication of anticoagulation (n = 3), failure of anticoagulation (n = 5), and prophylaxis (n = 61). The device was successfully deployed in the infrarenal (n = 95) or suprarenal (n = 1) IVC through a femoral vein approach. Retrieval was attempted in 11 patients after a mean period of 117 days (range: 24-426). The filter was successfully removed in nine patients (82%). Failure of retrieval was due to technical difficulty (n = 1) and the presence of thrombus in the filter (n = 1). One of the nine patients who had the filter removed developed IVC thrombus after retrieval and another had an intimal tear of the IVC. Follow-up abdominal CT (n = 40) at a mean of 80 days (range: 1-513) showed penetration of the IVC by the filter arms in 11, of which 3 had fracture of filter components. In one patient, a broken arm migrated into the pancreas. Asymmetric deployment of the filter legs was seen in 12 patients and thrombus within the filter in 2 patients. No filter migration or caval occlusion was encountered. Follow-up chest CT (n = 27) at a mean of 63 days (range: 1-386) showed PE in one patient (3%). During clinical follow-up, 12 of 96 patients developed symptoms of PE and only 1 of the 12 had PE on CT. There was no fatal pulmonary embolism in our group of patients following "Recovery" filter placement. However, the current version of the filter is associated with structure weakness, a high incidence of IVC wall penetration, and asymmetric deployment of the filter legs.

Optional vena cava filters for patients with high thromboembolic risk: questions to be answered

The use of vena cava filters has increased rapidly over the past few years to more than 140,000 filters inserted worldwide in 2003. Continued improvements in filter design have increased the safety of intravascular caval filtration. Although there are many factors attributed to this increase, the most significant contributing factor has been the development of optional vena cava filters. That is, filters that can be left as a permanent device or can be removed endovascularly at a later date. Three filters are approved for removal in the United States, the Günther Tulip, the OptEase, and the Recovery. Recent reports have demonstrated the safety and feasibility of these devices in appropriate patients, but a number of questions have arisen regarding their use.

Wall-embedded Recovery Inferior Vena Cava Filters: Imaging Features and Technique for Removal

Retrievable inferior vena cava (IVC) filters may be removed when no longer needed or left in place as permanent filters. Removal of any of the currently available optionally retrieved IVC filters becomes more difficult when they are tilted. Tilting of an IVC filter can also lead the tip of the filter to become embedded into the wall of the IVC. This report describes a method for removal of the Recovery IVC filter with use of rigid bronchoscopy forceps when the tip of the filter is tilted and embedded in the IVC.

Removal of the OptEase Retrievable Vena Cava Filter Is Not Feasible after Extended Time Periods Because of Filter Protrusion Through the Vena Cava

BACKGROUND

Therapeutic and prophylactic vena cava filters (VCFs) are used to prevent pulmonary embolism. Concerns exist over placing a permanent filter in a young trauma patient. Recently, retrievable VCFs have become available. One such filter is the OptEase, which has a recommended time of removal of up to 23 days after insertion. Data supporting this recommendation are sparse. Many trauma patients will need filters for more than 2 weeks, and there are no data evaluating the safety of removal after extended time periods. The purpose of this study was to determine the safety, feasibility, and reaction of the vena cava when removing the OptEase retrievable VCF at different time intervals.

METHODS

Twenty Yorkshire cross pigs (80-113 kg) underwent general anesthesia with tiletamine and zolazepam. Filters were placed in the infrarenal vena cava (VC) through the femoral vein under fluoroscopic guidance. Animals were then divided into four groups. In group 1, filters were removed at 14 days; in group 2, at 30 days; in group 3, at 60 days; and in group 4, at 90 days. Removal was attempted using a snare-and-sheath technique through the femoral vein. Animals with successful filter removal were allowed to recover; then, the animals underwent autopsy (gross and microscopic VC examination) 2 months later. Animals with unsuccessful filter removal underwent autopsy immediately after attempted removal. Venacavograms were taken at filter insertion, at removal, and before autopsy to evaluate any VC abnormalities.

RESULTS

Successful removal of the filter in all five pigs (100%) was reliably performed only in the 14-day group. In this group, the initial VC transverse diameter was 19.4 +/- 0.8 mm and was significantly reduced to 9.8 +/- 1.1 mm (p < 0.05) immediately after removal. Sixty days later, before autopsy, VC diameter had increased to 15.3 +/- 1.9 mm, which was significantly larger than at removal (p < 0.05) but not different from the initial value. In the 30-day group, removal was successful in only one of five animals. Although removal was successful in the one pig, autopsy at 2 months postremoval revealed total occlusion of the VC. Filters could not be removed from 60- and 90-day groups. At autopsy, the VCF struts were embedded or protruded through the VC wall. Microscopic examination of the VC revealed significant scarring underneath and between the struts.

CONCLUSION

Removal of the retrievable OptEase VCF may be successfully performed up to 14 days after insertion. Strut protrusion through the VC wall prohibited successful and safe removal at extended time intervals.

Experience with the Recovery Filter as a Retrievable Inferior Vena Cava Filter

PURPOSE

This study evaluates clinical experience with the Recovery filter as a retrievable inferior vena cava (IVC) filter.

MATERIALS AND METHODS

One hundred seven Recovery filters were placed in 106 patients with an initial clinical indication for temporary caval filtration. Patients were followed up to assess filter efficacy, complications, eventual need for filter removal, time to retrieval, and ability to remove the filter.

RESULTS

The patient cohort consisted of 62 men and 44 women with a mean age of 48 years (range, 18-90 y). Mean implantation time was 165 days. Indications for filter placement in patients with deep vein thrombosis (DVT) and/or pulmonary embolism (PE) included contraindication to anticoagulation (n = 33), complications of anticoagulation (n = 8), poor cardiopulmonary reserve (n = 6), large clot burden (n = 3), and PE while receiving anticoagulation (n = 1). Indications for filter placement in patients without proven PE or DVT included immobility after trauma (n = 35); recent intracranial hemorrhage, neurosurgery, or brain tumor (n = 18); and other surgical or invasive procedure (n = 3). Three patients (2.8%) had symptomatic PE after placement of the Recovery filter. No caval thromboses were detected. No symptomatic filter migrations occurred. Recovery filter removal was attempted in 15 of 106 patients (14%) at a mean of 150 days after placement. The Recovery filter was successfully retrieved in 14 of 15 patients (93%); one removal was unsuccessful at 210 days after placement. Ninety-two filters (87%) currently remain in place.

CONCLUSIONS

Although all the filters were placed with the intention of being removed, a large percentage of filters were not retrieved. The Recovery filter was safe and effective in preventing PE when used as a retrievable IVC filter.