Removal of Retrievable Inferior Vena Cava Filters with Computed Tomography Findings Indicating Tenting or Penetration of the Inferior Vena Cava Wall

Grasp-and-Fold Technique for Complex Inferior Vena Cava Filter Retrieval

This study evaluated the use of the grasp-and-fold technique for complex forceps retrieval of inferior vena cava (IVC) filters. A retrospective study of 14 patients (12 women and 2 men) who had either deeply tip-embedded or severely distorted IVC filters was performed at a single institution over 10 years. In this technique, endobronchial forceps were used to fold the filter in half to remove it through the sheath because the filter tip could not be accessed by dissection. The grasp-and-fold technique successfully removed all 14 filters. One patient had retained filter struts, which were present before the procedure. One mild and 5 moderate adverse events (AEs), including fracture fragment embolization requiring retrieval and self-limited IVC extravasation, occurred. No severe AEs occurred. In this small patient cohort, the grasp-and-fold forceps technique successfully retrieved deeply tip-embedded or distorted IVC filters with inaccessible tips.

Retrieval of a Cook Celect inferior vena cava (IVC) filter after prolonged dwell time of 5,117 days: Factors to consider for retrieval of long-dwell IVC filters

Inferior vena cava (IVC) filters are used in certain patients to help prevent the occurrence of pulmonary embolism (PE). IVC filters are generally recommended to be removed once PE prophylaxis is no longer required. Long-dwelling IVC filters are associated with higher complication rates (Vasa 2020; 49: 449), being more difficult to retrieve and associated with higher retrieval complications (Cardiovasc Diagn Ther 2016; 6: 632). This report describes the pre-procedural work-up and removal of an IVC filter with a prolonged dwell time of 5,117 days (14 years, 3 days) using the loop snare advanced retrieval technique. As far as the authors are aware this case is the longest-described successful retrieval of a Cook Celect IVC filter at 5,117 days.

The wire loop technique for IVC filter removal

Inferior vena cava (IVC) filters are effective therapy to prevent pulmonary embolism in patients with contraindication to anticoagulation. However, IVC wall penetration by the filter struts is a common complication that can lead to symptoms specially when adjacent organs are impacted. This case report and video describe the wire loop technique for successful endovascular IVC filter retrieval in a patient with lower back pain caused by a spinal strut penetration. The patient's back pain resolved after filter retrieval and he remained stable on anticoagulation with no recurrence of venous thromboembolism.

Single center experience of inferior vena cava filter retrieval in trauma patients: contrast-enhanced CT-based retrieval within hospital stay

PURPOSE

To assess the safety and retrieval rate of a predischarge inferior vena cava (IVC) filter retrieval strategy based on contrast computed tomography (CT).

METHODS

IVC filter insertion for trauma patients from 2010 to 2018 were reviewed. An active filter retrieval strategy was established in March 2017. The strategy sought early evaluation of venous thromboembolism (VTE) status and filter retrieval before a patient's discharge. The possibility of early IVC filter retrieval was evaluated by a multidisciplinary team based on pre-filter retrieval VTE-CT findings. Overall VTE-CT findings, retrieval rate, indwelling time, and recurrence of venous thromboembolic events were compared before and after the filter retrieval strategy setup.

RESULTS

177 IVC filters were inserted in trauma patients. All patients underwent pre-filter retrieval VTE-CT. VTE-CT findings were as follows: completely resolved VTE, n = 108 (61%); partially improved, n = 58 (33%); no change, n = 8 (5%); aggravated, n = 3 (2%). The overall retrieval rate was 84% with a mean indwelling time of 32 days. In subgroup analyses, 95 (53%) had filter retrieval with the before strategy (BS) setup and 82 (47%) with the after strategy (AS) setup. The retrieval rate was significantly higher in the AS group [81/82 (99%) vs. 68/95 (72%), (p < 0.001)]. No patients had recurrent VTE during the follow-up period.

CONCLUSIONS

The active strategy of VTE-CT-based filter retrieval during the hospital stay markedly improved the filter retrieval rate from 72% to 99% without evidence of recurrence of VTE. Hazards of low retrieval rate versus CT-related radiation exposure should be studied in the future.

Impact of Advanced Technique on Improvement in the Retrievable Inferior Vena Cava Filter Retrieval Rate

BACKGROUND

It is recommended to remove retrievable inferior vena cava filters (r-IVCFs) when they are no longer needed because their presence may give rise to serious complications related to prolonged placement of the filter. An advanced filter retrieval technique may help improve the retrieval rate.

METHODS AND RESULTS

107 consecutive patients (mean age; 61±18 years, male 53%) in whom r-IVCF retrieval was attempted were prospectively enrolled between April 2012 and December 2018. The frequently used advanced techniques were sling technique and biopsy forceps dissection technique. Retrieval success was 75% with standard retrieval technique alone; however, the overall retrieval success rate improved to 98% with advanced techniques. We observed few serious complications related to the retrieval procedure. Logistic multivariate analysis identified prolonged indwelling time (P=0.0011) and embedded hook in the caval wall (P=0.0114) as independent predictors, and the cutoff value for the indwelling time for requirement of advanced technique was 80 days.

CONCLUSIONS

Advanced retrieval techniques helped improve the retrieval rate without serious complications. We may need to consider the referral of patients to centers with expertise in advanced retrieval techniques when the indwelling time is >80 days, and pre-retrieval CT image shows a hook embedded in the vessel wall.

Contemporary management of chronic indwelling inferior vena cava filters

OBJECTIVE

Despite increasing retrieval rates of the inferior vena cava (IVC) filter, less than one-third are removed within the recommended timeline. Prolonged filter dwell times may increase the technical difficulty of retrieval and filter-related complications. We sought to evaluate the contemporary outcomes of patients with chronic indwelling IVC filters at a tertiary care center.

METHODS

A retrospective analysis was performed from August 2015 through August 2019 of all patients who were referred for removal of a prolonged IVC filter with a dwell time >1 year. Descriptive analysis was used to evaluate patients' characteristics and procedural outcomes, which were reviewed through electronic medical records. Data were expressed as median with interquartile range (IQR) or number and percentage, as appropriate.

RESULTS

A total of 47 patients were identified with a median filter dwell time of 10.0 years (IQR, 6-13 years); 34 patients underwent IVC filter removal, and 13 patients refused retrieval. The median age of patients was 54.9 years (IQR, 42.5-64.0 years); the majority were female (57%) and white (53%). The most common indication for filter placement was high risk despite anticoagulation (49%), followed by venous thromboembolism prophylaxis (21%). The majority of patients were symptomatic (72%). If symptomatic, the most common reason for retrieval was IVC penetration (94%), and the chief complaint was pain (56%). Retrieval success was 97%, with a median length of stay of 0 days. The majority of retrievals were performed through an endovascular approach (97%). There was one postprocedural complication (3%).

CONCLUSIONS

Despite prolonged dwell times, IVC filter retrieval can be performed safely and effectively in carefully selected patients at a tertiary referral center.

Uncomplicated percutaneous IVC filter removal following implantation time of 6033 days

Pulmonary embolism (PE) is a major cause of morbidity and mortality in the United States and usually occurs secondary to venous thromboembolism. Inferior vena cava (IVC) filters are minimally invasive intravascular devices placed in patients who are at increased risk for venous thromboembolism leading to PE, however, has a contraindication to medical anticoagulation therapy. The longest reported case of a retrievable IVC filter has remained in place and successfully removed in a living patient has been 4753 days (13 years). We present a case of an uneventful, successful IVC removal with a dwell time of 6033 days (16 years).

Urinary excretion after transcaval renal penetration of a fragmented Bird's Nest filter

Permanent inferior vena cava (IVC) filters are used to prevent venous thromboembolic events in select populations of patients. The Bird's Nest filter (BNF; Cook Medical, Bloomington, Ind) is an IVC filter that has been associated with various complications including filter strut fractures, migration, caval wall perforation, visceral perforation, and vascular injury. We report a case of a BNF that eroded transmurally through the IVC into the right kidney parenchyma. The patient underwent operative intervention with removal of the BNF with an uncomplicated postoperative course. In patients with symptoms and local filter perforations, we advocate for safe filter removal when possible to avoid long-term damage.

Long-term computed tomography follow-up results of strut penetration of inferior vena cava filters

OBJECTIVE

This study aimed to investigate the incidence of inferior vena cava (IVC) filter strut penetration and risk factors of organ involvement.

METHODS

From June 2003 to August 2015, there were 138 patients with deep venous thrombosis who received an IVC filter. Among 104 patients who did not have the IVC filter retrieved, 66 had follow-up computed tomography and were included in this study. The IVC filters used were 21 Günther Tulip (Cook Medical, Bloomington, Ind), 26 Celect (Cook Medical), and 19 OptEase (Cordis Corp, Bridgewater, NJ) filters. Filter strut penetration was categorized by a previously published scale of grade 0 to grade 3, and organ involvement was specifically assessed. Multivariate analysis was used to identify risk factors for organ-involving strut penetration (grade 3).

RESULTS

The median age of the patients was 66 years (27-84 years), and 46% were male. Median computed tomography follow-up duration was 14 months (1-137 months). IVC strut penetration was detected in all patients. Grade 1, grade 2, and grade 3 were 29%, 36%, and 35%, respectively. The risk factor of grade 3 penetration was indwelling time ≥30 months on binary logistic regression analysis (odds ratio, 4.395; 95% confidence interval, 1.179-16.385; P = .027).

CONCLUSIONS

Regardless of type of IVC filter, the incidence of strut penetration was high. The risk of adjacent organ involvement increases over time. Retrievable IVC filters need close follow-up and retrieval as soon as they are no longer needed.

Asymptomatic patients with unsuccessful percutaneous inferior vena cava filter retrieval rarely develop complications despite strut penetrations through the caval wall

OBJECTIVE

We established a program for retrieval of inferior vena cava (IVC) filters within our hospital system. When percutaneous retrieval fails, we only recommend open surgical removal for symptoms and other complications. We examined our outcomes with conservative management of unsuccessful percutaneous retrieval and open surgical removal for symptomatic/complicated IVC filters.

METHODS

All patients with history of IVC filter placement who were referred to us for retrieval between 2010 and 2016 were evaluated. Before retrieval, patients were evaluated for risk of future venous thromboembolic events and ongoing need for IVC filtration. Asymptomatic patients with unsuccessful percutaneous filter retrieval were recommended to have annual follow-up with plain abdominal radiographs and to take daily low-dose aspirin. Patients with symptoms referable to the indwelling filter and those with complications were offered open surgical removal.

RESULTS

There were 213 patients with a history of IVC filter placement who underwent 220 percutaneous attempts for retrieving 214 IVC filters (four patients had two attempts, one patient had three attempts). Technical success in percutaneously retrieving the filter was 180 of 214 (84.1%) at a median of 5.5 months (interquartile range [IQR], 3.5-9.2) from implant. The median filter dwell time was significantly longer in unsuccessful compared with successful retrieval attempts (8.3 months [IQR, 4.3-15.1 months] vs 5.5 months [IQR, 3.2-8.7 months]; P = .011). Of the 34 filters in 33 patients that could not be retrieved percutaneously, all had either significant filter barb penetration through the caval wall or a tilt angle of greater than 15°. The majority of patients (67%) remained asymptomatic without any further complications over a mean follow-up of 24 months (IQR, 12-50 months). No asymptomatic patients developed symptoms or complications over the follow-up period. Two of the five patients who were symptomatic underwent open surgical removal via minilaparotomy. An additional six patients who failed percutaneous retrieval at other institutions were referred to us for open surgical removal owing to symptoms or complications. Technical success for all open surgical removal of IVC filters was 100%. All patients had resolution of their symptoms after percutaneous or open surgical removal.

CONCLUSIONS

Asymptomatic patients with unsuccessful percutaneous IVC filter retrieval seem to have low complications in midterm follow-up despite significant filter strut penetration. Without symptoms or other complications, such patients do not require referral for open surgical filter removal. Symptomatic patients can expect low morbidity and resolution of symptoms after percutaneous or open surgical removal. Further studies are needed to determine the cost-effectiveness of routinely removing asymptomatic IVC filters.

Factors Affecting Inferior Vena Cava Filter Retrieval: A Review

Objective:

Over the last 2 decades, there has been an exponential rise in placement of retrievable inferior vena cava (IVC) filters, while the retrieval rate has remained steadily low. Approaches to increasing filter retrieval rates have been extensively studied.

Conclusion:

This review presents an up-to-date review of reported data-driven variables that affect retrieval rates of IVC filters, with a focus on clinical, technical, and process factors.

Is external compression on the IVC a risk factor for IVC filter abutment? A single center experience of 141 infrarenal celect filter insertions

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Tilt of the IVC filter is the major problem for the filter retrieval rate.

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External compression on the IVC wall can cause filter tilting.

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Identifying external compression factors are necessary before insertion of IVC filter.

Objectives

To investigate risk factors for inferior vena cava (IVC) filter abutment, including external compression on the IVC wall, using venous phase computed tomography (CT).

Methods

One-hundred-forty-one cases of Celect IVC filter insertion between January 2009 and April 2017 were retrospectively reviewed. On pre-procedural CT, IVC diameter and morphological classifications were measured. Filter tilt angle, IVC angle, vertical position, and filter tip abutment to the IVC wall were analyzed on post-procedural CT. IVC compression was examined by pre- and post-procedural CT analysis. Multiple logistic regression analysis was conducted to find factors related to IVC filter abutment.

Results

Of 141 IVC filter insertion cases, 52 were classified in the filter tip abutment group and 89 in the non-abutting group. IVC tilt angle (11.7 ± 5.5° vs. 6.4 ± 5.4°), presence of external compression (14/52, 27% vs. 9/89, 9%), and IVC morphology were different between the groups (p < 0.05). In multiple logistic regression analysis, filter-tilt angle over 9.25° and external compression on the IVC were found to be independent predictors of filter abutment (odds ratios: 4.56, 10.18, respectively).

Conclusion

IVC filter tilt, external compression on IVC wall, and IVC morphology were significantly different between the filter tip abutment and non-abutment groups. External compression and filter tilt over 9.25° were risk factors for filter tip abutment in multiple logistic regression analysis. By identifying these factors, we may be able to reduce filter tilting by preventing the filter from being deployed in a dangerous area.

Reporting of Inferior Vena Cava Filter Complications on CT: Impact of Standardized Macros

OBJECTIVE

The objective of our study was to report the effect of implementing standardized inferior vena cava filter (IVCF) macros on the reporting of IVCFs and filter-related complications in abdominal CT reports.

MATERIALS AND METHODS

Retrospective analysis was performed of all abdominal CT reports performed between October 2014 and January 2015 before implementation of IVCF macros (n = 5143). Duplicated examinations and studies requested specifically to evaluate known IVCFs were excluded. In March 2016, normal and abnormal standardized IVCF macros were implemented. Two radiologists reviewed all CT abdominal reports using IVCF macros between March 2016 to July 2016 to assess for missed IVCF complications.

RESULTS

Before the implementation of the IVCF macros, 146 of 5143 (2.8%) abdominal CT studies (89 men and 57 women; mean age, 59 years) showed an IVCF. After implementation of IVCF macros, 105 abdominal CT studies using the IVCF macros were analyzed (48 men and 57 women; mean age, 58 years), including 73 normal macros and 32 abnormal macros). The rate of reported caval penetration and filter element-organ interaction improved from 12% (9/73) to 57% (28/49) (p < 0.001) and from 0% (0/53) to 36% (9/25) (p < 0.001) before and after macro implementation, respectively. However, one filter fracture and two filter-associated thrombi were missed when using the IVCF macros.

CONCLUSION

Implementation of standardized IVCF macros improves reporting of IVCFs and IVCF-associated complications in abdominal CT reports.

Calibration of interface properties and application to a finite element model for predicting vena cava filter-induced vein wall failure

We present a computational framework that integrates experimental techniques and finite element modeling to calibrate material fracture parameters of the vena cava and the interaction properties between a retrievable filter (Günther Tulip) and the vena cava wall. The fitted parameters were then used to analyze the interaction of the inferior vena cava filter with the vena cava during the deployment process. An idealized cava finite element model was then developed including residual stresses and physiological pressure conditions. Filter deployment was simulated, and a comprehensive study of tissue-filter interaction was performed by cohesive surface modeling. Simulations predict that there are no fracture areas for either model, so we can conclude that there is no penetration of the anchor into the vena cava. This suggests there are other physiological situations, such as the Valsalva maneuver, which could produce this penetration observed on some patients.

Atrophic inferior vena cava is a marker of chronicity of intra-filter and inferior vena cava thrombosis: based on CT findings

Background

A permanently indwelling filter in the inferior vena cava (IVC) may induce caval thrombosis, which could develop and evolve from an acute to a chronic phase. The differential diagnosis of acute and chronic thromboses determines the treatment strategy. The role of computed tomography (CT) in diagnosing acute and chronic intra-filter and IVC thromboses has not been well established. This retrospective study summarizes the CT signs that indicate acute and chronic phases of intra-filter and IVC thromboses.

Methods

This study included eight patients who developed a lower-extremity deep venous thrombosis (DVT) and were treated with intracaval filter placement as an alternative to anticoagulation and thrombolysis. During the follow-up, all patients developed an intra-filter thrombosis in the IVC confirmed by CT and/or CT venography (CTV). Demographic and CT data of all patients during the follow-up period were collected for analysis.

Results

All patients had normal-appearing IVCs prior to filter placement, as shown on trans-femoral venography. Eight filters (five TrapEase, three OptEase) were placed in the eight IVCs, respectively. Subsequently, IVC-CT or CTV revealed acute intra-filter or IVC thrombosis in all eight patients, manifesting as an intracaval filling defect and thickened IVC wall. Filter protrusion and secondary caval atrophy seen on CT indicated a chronically occluded IVC.

Conclusions

IVC thrombosis may result from filter placement. The chronicity of caval thrombotic occlusion is likely to be associated with filter protrusion and secondary IVC atrophy revealed on CT scans.

Endovascular Removal of Inferior Vena Cava Filters with Arterial Penetration

PURPOSE

To evaluate the safety and outcomes of endovascular percutaneous removal of inferior vena cava filters (IVCFs) with elements penetrating an artery.

MATERIALS AND METHODS

From an IVCF retrieval database, computerized tomographic scans of patients who underwent IVCF retrieval from 2011 to 2017 were reviewed for IVCF elements penetrating through the caval wall and into an adjacent arterial wall (AW) or penetrating into an adjacent arterial lumen (AL). Forty-two patients were identified, including 20 with elements penetrating into an AW and 22 with elements penetrating into an AL; 30 of these IVCFs were tip embedded.

RESULTS

All of the filters in both groups were removed. Of the arterial-interacting filters, 9 were removed with the use of standard techniques and 33 with the use of endobronchial forceps. Arterial access was obtained before removal in 3 patients (7%) with post-removal arteriography revealing no abnormalities, such as extravasation, pseudoaneurysm, or new fractured components. There was no significant difference between groups in tip embedding, retrieval technique, or fluoroscopy time.

CONCLUSIONS

Endovascular removal of IVCFs with elements that have penetrated into adjacent arterial walls or lumens can be performed safely in the majority of patients.

Should We Remove the Retrievable Cook Celect Inferior Vena Cava Filter? Eight Years of Experience at a Single Center

Background

The inferior vena cava filter (IVCF) is very effective for preventing pulmonary embolism in patients who cannot undergo anticoagulation therapy. However, if a filter is placed in the body permanently, it may lead to other complications.

Methods

A retrospective study was performed of 159 patients who underwent retrievable Cook Celect IVCF implantation between January 2007 and April 2015 at a single center. Baseline characteristics, indications, and complications caused by the filter were investigated.

Results

The most common underlying disease of patients receiving the filter was cancer (24.3%). Venous thrombolysis or thrombectomy was the most common indication for IVCF insertion in this study (47.2%). The most common complication was inferior vena cava penetration, the risk of which increased the longer the filter remained in the body (p=0.032, Exp(B)=1.004).

Conclusion

If the patient is able to retry anticoagulation therapy and the filter is no longer needed, the filter should be removed, even if a long time has elapsed since implantation. If the filter cannot be removed, it is recommended that follow-up computed tomography be performed regularly to monitor the progress of venous thromboembolisms as well as any filter-related complications.

Novel and Advanced Techniques for Complex IVC Filter Retrieval

OPINION STATEMENT

Inferior vena cava (IVC) filter placement is indicated for the treatment of venous thromboembolism (VTE) in patients with a contraindication to or a failure of anticoagulation. With the advent of retrievable IVC filters and their ease of placement, an increasing number of such filters are being inserted for prophylaxis in patients at high risk for VTE. Available data show that only a small number of these filters are retrieved within the recommended period, if at all, prompting the FDA to issue a statement on the need for their timely removal. With prolonged dwell times, advanced techniques may be needed for filter retrieval in up to 60% of the cases. In this article, we review standard and advanced IVC filter retrieval techniques including single-access, dual-access, and dissection techniques. Complicated filter retrievals carry a non-negligible risk for complications such as filter fragmentation and resultant embolization of filter components, venous pseudoaneurysms or stenoses, and breach of the integrity of the caval wall. Careful pre-retrieval assessment of IVC filter position, any significant degree of filter tilting or of hook, and/or strut epithelialization and caval wall penetration by filter components should be considered using dedicated cross-sectional imaging for procedural planning. In complex cases, the risk for retrieval complications should be carefully weighed against the risks of leaving the filter permanently indwelling. The decision to remove an embedded IVC filter using advanced techniques should be individualized to each patient and made with caution, based on the patient's age and existing comorbidities.

The Successful Removal of Two Retrievable Inferior Vena Cava (IVC) Filters after 67 Days in a Patient with a Double IVC

We herein present a case in which two retrievable inferior vena cava (IVC) filters, which were implanted to treat deep-vein thrombosis caused by the compression of a double IVC, were successfully removed on the 67th day after placement. The filters were individually placed in both the left and right IVCs. With a prevalence of only 0.2%, a double IVC is an extremely rare anatomical variation. The long-term effects of IVC filters are unknown, and the placement of a filter potentially introduces the risk of complications. Thus, if the patient's clinical condition allows, the endovascular retrieval of the filter should be considered within a few months after implantation.

Can Pre-Retrieval Computed Tomography Predict the Difficult Removal of an Implementing an Inferior Vena Cava Filter?

Purpose:

Implementing an inferior vena cava (IVC) filter is a relatively safe procedure but potential negative long-term effects. The complications for filter retrieval have been noted. We examined filter characteristics on pre-retrieval computed tomography (CT) that were associated with complicated retrieval (CR) of IVC filters.

Materials and Methods:

A retrospective review of IVC filter retrievals between January 2008 and June 2014 was performed to identify patients who had undergone a pre-retrieval CT for IVC filter retrieval. CR was defined as the use of nonstandard techniques, procedural time over 30 min, filter fractures, filter tip incorporation into the IVC wall, and retrieval failure. Pre-retrieval CT images were evaluated for tilt angle in the mediolateral and anteroposterior directions, tip embedding into the IVC wall, degree of filter strut perforation, and distance of the filter tip from the nearest renal vein.

Results:

Of seventy-six patients, twenty-four patients (31.6%) with CRs and 56 patients (73.7%) with non-CR were evaluated for pre-retrieval CT. For IVC filter retrieval with a dwelling time of over 45 days, a tilt of over 15 degrees, the appearance of tip embedding and grade 2 perforation were associated with CR on multivariate analysis. However, for IVC filter retrievals with a dwelling time of less than 45 days, there were no factors associated with CR.

Conclusion:

Pre-retrieval CTs may be more effective for IVC filters with a dwelling time of over 45 days. Therefore, a pre-retrieval CT may be helpful in predicting CR of IVC filters with long dwelling times.

Analysis of the Final DENALI Trial Data: A Prospective, Multicenter Study of the Denali Inferior Vena Cava Filter

PURPOSE

To report the final 2-year data on the efficacy and safety of a nitinol retrievable inferior vena cava (IVC) filter for protection against pulmonary embolism (PE).

MATERIALS AND METHODS

This was a prospective multicenter trial of 200 patients with temporary indications for caval filtration who underwent implantation of the Denali IVC filter. After filter placement, all patients were followed for 2 years after placement or 30 days after filter retrieval. The primary endpoints were technical success of filter implantation in the intended location and clinical success of filter placement and retrieval. Secondary endpoints were incidence of clinically symptomatic recurrent PE, new or propagating deep vein thrombosis (DVT), and filter-related complications including migration, fracture, penetration, and tilt.

RESULTS

Filter placement was technically successful in 199 patients (99.5%). Filters were clinically successful in 190 patients (95%). The rate of PE was 3% (n = 6), with 5 patients having a small subsegmental PE and 1 having a lobar PE. New or worsening DVT was noted in 26 patients (13%). Filter retrieval was attempted 125 times in 124 patients and was technically successful in 121 patients (97.6%). The mean filter dwell time at retrieval was 200.8 days (range, 5-736 d). There were no instances of filter fracture, migration, or tilt greater than 15° at the time of filter retrieval or during follow-up.

CONCLUSIONS

The Denali IVC filter exhibited high success rates for filter placement and retrieval while maintaining a low complication rate in this clinical trial.

IVC filter retrieval in adolescents: experience in a tertiary pediatric center

BACKGROUND

Inferior vena cava (IVC) filters are commonly implanted with the intent to prevent life-threatening pulmonary embolism in at-risk patients with contraindications to anticoagulation. Various studies have reported increases in the rate of venous thromboembolism within the pediatric population. The utility and safety of IVC filters in children has not yet been fully defined.

OBJECTIVE

To describe the technique and adjunctive maneuvers of IVC filter removal in children, demonstrate its technical success and identify complications.

MATERIALS AND METHODS

A retrospective 10-year review was performed of 20 children (13 male, 7 female), mean age: 15.1 years (range: 12-19 years), who underwent IVC filter retrieval. Eleven of 20 (55%) were placed in our institution. Electronic medical records were reviewed for filter characteristics, retrieval technique, technical success and complications.

RESULTS

The technical success rate was 100%. Placement indications included: deep venous thrombosis with a contraindication to anticoagulation (10/20, 50%), free-floating thrombus (4/20, 20%), post-trauma pulmonary embolism prophylaxis (3/20, 15%) and pre-thrombolysis pulmonary patient (1/20, 5%). The mean implantation period was 63 days (range: 20-270 days). Standard retrieval was performed in 17/20 patients (85%). Adjunctive techniques were performed in 3/20 patients (15%) and included the double-snare technique, balloon assistance and endobronchial forceps retrieval. Median procedure time was 60 min (range: 45-240 min). Pre-retrieval cavogram demonstrated filter tilt in 5/20 patients (25%) with a mean angle of 17° (range: 8-40). Pre-retrieval CT demonstrated strut wall penetration and tip embedment in one patient each. There were two procedure-related complications: IVC mural dissection noted on venography in one patient and snare catheter fracture requiring retrieval in one patient. There were no early or late complications.

CONCLUSION

In children, IVC filter retrieval can be performed safely but may be challenging, especially in cases of filter tilt or embedding. Adjunctive techniques may increase filter retrieval rates.

Successful Endovascular Removal of a Perforated Inferior Vena Cava Filter Complicated by a Large Retroperitoneal Hematoma: Pitfall of Catheter-Directed Thrombolysis

Symptomatic caval perforation is rare complication after inferior vena cava (IVC) filter insertion. A 44-year-old woman developed back pain after the placement of retrieval IVC filter during catheter-directed thrombolysis (CDT). Her computed tomography showed a large right-sided retroperitoneal hematoma. After 2 weeks, endovascular removal of the perforated filter was successfully performed without complication. Because thrombolytic agents can accelerate bleeding caused by endovascular procedures, the bleeding rate of the IVC filter deployment during CDT might be higher than expected.

Retrievable Filter Update: The Denali Vena Cava Filter

Over the past decade, there has been a gradual evolution of the retrievable inferior vena cava (IVC) filter, as the indications for caval filtration have expanded since the first such filters came into use. However, the particular design of retrievable or optional filters has introduced a subset of both symptomatic and asymptomatic device failures that have prompted a reassessment in the approach to patient selection as well as a new lexicon of technical considerations when considering retrieval. The Denali Vena Cava Filter (Bard Peripheral Vascular, Inc., Tempe, AZ) represents one of the latest filters to come to market that specifically addresses the various issues of its predecessors. While the body of published experience with this filter is still relatively sparse, the incidence of filter tilt, strut perforation, strut fracture, and filter migration appears acceptably low and the filters remain relatively easy to retrieve even after long dwell times.

Inferior vena cava filters: current best practices

Venous thromboembolism (VTE) is a common cause of inpatient and outpatient morbidity and mortality. While anticoagulant therapy is considered the primary means of prevention and treatment of VTE, inferior vena cava filters (IVCFs) are often used as an alternative or adjunct to anticoagulation. With the advent of retrievable filters indications have liberalized, to include placement for primary prophylaxis in high-risk patients. However, this practice is based on limited evidence supporting their efficacy in preventing clinically relevant outcomes. Since indiscriminate use of IVCFs can be associated with net patient harm and increased health care costs, knowledge of the literature surrounding IVCF utilization is critical for providers to adopt best practices. In this review, we will provide an overview of the literature as it relates to specific clinical questions that arise when considering IVCF utilization in the prevention and treatment of VTE. Practice-based recommendations will be reviewed to provide the clinician with guidance on challenging clinical scenarios.

Failure properties of vena cava tissue due to deep penetration during filter insertion

In this work, we use an in-vitro mechanical test to explore the resistance of biaxially stretched vena cava tissue against deep perforation and a methodology which integrates experimental and numerical modeling to identify constitutive fracture properties of the vena cava. Six sheep vena cava were harvested just after killing, and cyclic uniaxial tension tests in longitudinal and circumferential directions and biaxial deep penetration tests were performed. After that, we use a nonlinear finite element model to simulate in vitro penetration of the cava tissue in order to fit the fracture properties under penetration of the vena cava by defining a cohesive fracture zone. An iterative process was developed in order to fit the fracture properties of the vena cava using the previously obtained experimental results. The proposed solutions were obtained with fracture energy of 0.22 or 0.33 N/mm. In comparison with the experimental data, the simulation using [Formula: see text], [Formula: see text], and [Formula: see text] parameters ([Formula: see text]) is in good agreement with results from penetration experiments of cava tissue. It is noticeable that the parameter estimation process of the fracture behavior is more accurate than the estimation process of the elastic behavior for the toe region of the curve.

Endovascular Interventions for Acute and Chronic Lower Extremity Deep Venous Disease: State of the Art

The societal and individual burden caused by acute and chronic lower extremity venous disease is considerable. In the past several decades, minimally invasive endovascular interventions have been developed to reduce thrombus burden in the setting of acute deep venous thrombosis to prevent both short- and long-term morbidity and to recanalize chronically occluded or stenosed postthrombotic or nonthrombotic veins in symptomatic patients. This state-of-the-art review provides an overview of the techniques and challenges, rationale, patient selection criteria, complications, postinterventional care, and outcomes data for endovascular intervention in the setting of acute and chronic lower extremity deep venous disease. Online supplemental material is available for this article.

Caval Penetration by Inferior Vena Cava Filters

Background—

Limited penetration into the caval wall is an important securing mechanism for inferior vena cava (IVC) filters; however, caval penetration can also cause unintentional complications. The aim of this study was to assess the incidence, severity, clinical consequences, and management of filter penetration across a range of commercially available IVC filters.

Methods and Results—

The MEDLINE database was searched for all studies (1970–2014) related to IVC filters. A total of 88 clinical studies and 112 case reports qualified for analysis; these studies included 9002 patients and 15 types of IVC filters. Overall, penetration was reported in 19% of patients (1699 of 9002), and 19% of those penetrations (322 of 1699) showed evidence of organ/structure involvement. Among patients with penetration, 8% were symptomatic, 45% were asymptomatic, and 47% had unknown symptomatology. The most frequently reported symptom was pain (77%, 108 of 140). Major complications were reported in 83 patients (5%). These complications required interventions including surgical removal of the IVC filter (n=63), endovascular stent placement or embolization (n=11), endovascular retrieval of the permanent filter (n=4), and percutaneous nephrostomy or ureteral stent placement (n=3). Complications led to death in 2 patients. A total of 87% of patients (127 of 146) underwent premature filter retrieval or interventions for underlying symptoms or penetration-related complications.

Conclusions—

Caval penetration is a frequent but clinically underrecognized complication of IVC filter placement. Symptomatic patients accounted for nearly 1/10th of all penetrations; most of these cases had organ/structure involvement. Interventions with endovascular retrieval and surgery were required in most of these symptomatic patients.

The CIRSE Retrievable IVC Filter Registry: Retrieval Success Rates in Practice

CIRSE established a registry of retrievable filter use with the primary aim of determining the success of IVC Filter retrieval and associated complications. Secondary endpoints included filter indications, imaging strategies before retrieval, filter dwell times, and anticoagulation status. A web-based electronic registry was hosted between 01/12/2010 and 30/06/2012. Data entry occurred at the date of IVC filter retrieval and included items such as filter type, indication for filter insertion, access route, dwell time, retrieval success, complications, reasons for failed retrieval, and anticoagulation status. 671 filter retrievals were entered (male:female 333:295, mean age 55, median 57). Retrieval data were not entered in 43/671 leaving 628 patients for analysis. The 4 commonest retrievable filters used were the Celect in 182 patients, the OPTEASE in 161, ALN in 120, and Gunther Tulip in 98. Filters were inserted for absolute indications 40%, relative indications in 31%, and prophylactic in 24%, with 5% missing. Mean filter dwell time was 90 days. Filters were successfully retrieved in 576/628 patients (92%). The mean dwell time for successful retrievals was 85 days versus 145 days for unsuccessful retrievals (p = 0.001). Major complications occurred in 2 patients (0.03%). In summary, the CIRSE retrievable filter registry demonstrates a retrieval rate of 92% across a range of filter types, with a low major complication rate, reflecting current practice. There is an increase in trend of retrievable filter use for relative and prophylactic indications.

Respiratory-Induced Haemodynamic Changes: A Contributing Factor to IVC Filter Penetration

PURPOSE

The purpose of the study is to evaluate the influence of respiratory-induced vena caval hemodynamic changes on filter migration/penetration.

MATERIALS AND METHODS

After placement of either a Gunther Tulip or Celect IVC filter, 101 consecutive patients scheduled for filter retrieval were prospectively enrolled in this study. Pre-retrieval CT scans were used to assess filter complications and to calculate cross-sectional area in three locations: at level of filter strut fixation, 3 cm above and 3 cm below. A 3D finite element simulation was constructed on these data and direct IVC pressure was recorded during filter retrieval. Cross-sectional areas and pressures of the vena cava were measured during neutral breathing and in Valsalva maneuver and identified filter complications were recorded. A statistical analysis of these variables was then performed.

RESULTS

During Valsalva maneuvers, a 60 % decrease of the IVC cross-sectional area and a fivefold increase in the IVC pressure were identified (p < 0.001). There was a statistically significant difference in the reduction of the cross-sectional area at the filter strut level (p < 0.001) in patient with filter penetration. Difficulty in filter retrieval was higher in penetrated or tilted filters (p < 0.001; p = 0.005). 3D computational models showed significant IVC deformation around the filter during Valsalva maneuver.

CONCLUSION

Caval morphology and hemodynamics are clearly affected by Valsalva maneuvers. A physiological reduction of IVC cross-sectional area is associated with higher risk of filter penetration, despite short dwell times. Physiologic data should be used to improve future filter designs to remain safely implanted over longer dwell times.

Günther-Tulip inferior vena cava filter removal 3334 days after placement

The Günther-Tulip inferior vena cava filter (Cook Medical Inc, Bloomington, Ind) was one of the first inferior vena cava (IVC) filters to be approved by the U.S. Food and Drug Administration for retrieval. Clinical experience has documented that these IVC filters may be safely removed after 12 weeks of implantation. Recent reports have shown that the longer the indwelling time, the higher the retrieval failure rate. We present a case of a successful retrieval of a Günther-Tulip IVC filter 3334 days after implantation. Removal of the Günther-Tulip IVC filter is technically feasible, even after a prolonged indwelling time.

Strut penetration: local complications, breakthrough pulmonary embolism, and retrieval failure in patients with Celect vena cava filters

PURPOSE

To investigate strut penetration in patients with Celect filters, specifically local complications and association with breakthrough pulmonary embolism (PE) or retrieval failure.

MATERIALS AND METHODS

A retrospective single-center study was conducted to evaluate patients who received Celect filters between January 2007 and May 2013. A total of 595 filters were placed during the study period. Primary indications included thromboembolic disease (93%) and primary surgical prophylaxis (7%). Complications and retrieval data were assessed by computed tomography (CT) and electronic medical records.

RESULTS

A total of 193 patients underwent follow-up abdominal CT at a mean follow-up interval of 176.2 days (range, 0-1,739 d). The rate of strut penetration more than 3 mm outside the caval wall was 28.5% (n = 55). One patient had CT evidence of clinically major strut penetration (1.8%) with strut compression of the right ureter causing hydronephrosis. Indwelling filter time longer than 100 days was associated with strut penetration (P < .001). Age, sex, and history of thromboembolic disease were not associated with strut penetration (P = .51, P = .81, and P = .89). Sixty-three patients presented for follow-up CT pulmonary angiography at a mean of 128.1 days (range, 1-895 d). The rate of breakthrough PE was 12.7%. The overall retrieval success rate was 96.7% (n = 150). Strut penetration was not associated with breakthrough PE or retrieval failure (P = .49 and P = .22).

CONCLUSIONS

Although strut penetration is a common complication with Celect filters, there is no association with breakthrough PE or retrieval failure. CT evidence of local complications associated with strut penetration is rare.

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.

Penetration of the inferior vena cava and adjacent organs after filter placement is associated with retrievable filter type and length of time in place

OBJECTIVE

Concern over local complications of inferior vena cava (IVC) filters exists, but little long-term data are available. Referrals for filter penetrations on computed tomography (CT) have increased with no standards for management. We reviewed postfilter CT findings in our institution.

METHODS

All patients receiving IVC filters between January 1, 2006 and December 31, 2009 with a postfilter CT were reviewed. Penetration was graded with a previously published scale. Filter indication, type, and subsequent encounters for abdominal or back pain were recorded.

RESULTS

A total of 591 patients had a filter during the study period. Of these, 262 had an adequate postfilter CT, comprising the study group. Indications were prophylaxis in 16.4% and venous thromboembolism in 83.6%. Of filters placed for venous thromboembolism, indications were absolute (inability/failure of anticoagulation) in 44.7% and relative in 55.3%. Retrievable filters made up 92.7% of the filters, and 7.3% were permanent type. Of the retrievable filters, 1.6% were retrieved. One hundred twenty (45.8%) filters had grade 2 or 3 penetration. Another 38.2% (100) had struts immediately adjacent to the external aspect of the IVC, which may represent tenting of the cava. Grade 2 or 3 penetration occurred in 49.0% of retrievable filters but only 5.3% of permanent filters (P = .0001). Grade 2 or 3 penetration occurred in 18.2% of filters less than 30 days old but in 57.3% of filters 30 days old or older (P < .0001). Thirty-two patients had subsequent encounters for abdominal or back pain, but none was conclusively related to penetration.

CONCLUSIONS

A majority of filters were placed for prophylaxis or relative indications and were retrievable type. Retrieval rate was low. Penetration of the IVC and adjacent organs was common and associated with retrievable type and length of time in place. It is unclear if most penetrations cause problems. Monitoring of penetrations with CT may be important to understand the natural history of this condition.

Clinical course and predictive factors for complication of inferior vena cava filters

RATIONALE

The use of inferior vena cava (IVC) filters is associated with various complications. We aimed to elucidate the clinical course and predictive factors for complications of IVC filters, especially IVC penetration

METHODS

A retrospective observational study was performed in 45 adult patients with retrievable IVC filters and follow-up computed tomography (CT) between January 2003 and December 2012. Primary outcomes were the prevalence and predictive factors of IVC penetration. Secondary outcome was other complications of IVC filters.

RESULTS

IVC penetration following filter placement occurred in 87.6% of patients, and 57.8% of those involved significant penetration. Embedding of filter tips, suggestive of lateral tilting, was observed in 51.1%. Both Vertebral body erosions and aortic penetrations were seen in 4.4%, but they were asymptomatic. Longer indwelling duration of the IVC filter was significantly associated with a higher grade of IVC penetration, and the risk of significant IVC penetration increased in patients with the filter indwelling time of more than 20 days and an IVC diameter of less than 24.2mm.

CONCLUSIONS

In patients with a retrievable IVC filter, IVC penetration on CT was common, and significant IVC penetration was associated with a longer indwelling time of the IVC filter and a lesser IVC diameter.