Short- and Long-term Retrievability of the Celect Vena Cava Filter: Results from a Multi-institutional Registry

Two-Year Outcomes from the Cook Inferior Vena Cava Filter (CIVC) Study

PURPOSE

To report 2-year outcomes from a prospective, multicenter, nonrandomized, single-arm study designed to further assess the safety and effectiveness of the Celect and Günther Tulip Vena Cava Filters.

MATERIALS AND METHODS

The Cook Inferior Vena Cava Filter (CIVC) study enrolled patients requiring temporary or permanent inferior vena cava (IVC) filter placement for the prevention of pulmonary embolism (PE). The primary effectiveness endpoint was the rate of technical placement success and 12-month freedom from new symptomatic PE while a filter was indwelling. The primary safety endpoint was the rate of 12-month freedom from major adverse events. The primary endpoints were assessed for the Celect stratum, and secondary endpoints and secondary measures were assessed for the Celect stratum and Günther Tulip stratum. Follow-up was through 2 years or 1 month following retrieval.

RESULTS

Between 2014 and 2017, 473 patients (57.3% male; mean age, 61.1 years [SD ± 16.1]) were enrolled at 28 institutions: 324 in the Celect stratum and 149 in the Günther Tulip stratum. Filters were primarily placed for current deep vein thrombosis (48.4%) and/or current PE (20.7%). The primary effectiveness endpoint rate was 97.8%. The protocol analysis yielded a primary safety rate of 81.5% (P = .369); however, the post hoc analysis resulted in a primary safety rate of 86.7% (P = .001). The rate of successful filter retrieval was 94.9%. Only 2 patients had symptomatic filter leg interactions with the IVC. One death was adjudicated as device-/procedure-related.

CONCLUSIONS

CIVC study results support the safety and effectiveness of the Celect and Günther Tulip filters for the prevention of PE.

Information Disclosure, Medical Device Regulation, and Device Safety: The Case of Cook Celect IVC Filters

Although medical devices are widely used in clinical practice, clinicians and the public have limited access to information on how devices are tested, regulated, and used, posing challenges to patient safety. This article uses Cook Medical's Celect inferior vena cava (IVC) filter, a medical device used for prevention of pulmonary embolism, as a case study of the transparency gap in medical device regulation. Recently unsealed court documents from litigation related to Celect reveal that the device's clinical study protocol did not follow U.S. Food and Drug Administration (FDA) guidance for IVC filter testing and that study outcome definitions for IVC perforation had lower sensitivity for detecting adverse events than those recommended by professional societies. Furthermore, a comparison of court documents and the public record indicates that adverse events and patient deaths were misreported to FDA reviewers and were inaccurately reported in the published literature and on the device label, providing patients and clinicians with inaccurate information about the device's safety. The Celect IVC filter case demonstrates the need for regulatory reforms to ensure that critical safety data are accessible to the FDA, clinicians, and patients to inform decision making.

Endobronchial Forceps Retrieval of Embedded Inferior Vena Cava Filters: Retrieval of 535 Filters at a Single Center

PURPOSE

To report results of 16 years of using the endobronchial forceps technique to remove embedded inferior vena cava (IVC) filters.

MATERIALS AND METHODS

Between January 2005 and June 2021, 534 patients (310 women and 224 men) with a mean age of 52 years (standard deviation [SD] ± 16 years) presented for complex filter retrieval of 535 tip- or strut-embedded IVC filters. Tip-embedded filters were diagnosed on rotational venography. Filters were considered strut-embedded if they were closed-cell filters with dwell times of >6 months. The filter was dissected from the IVC using rigid bronchoscopy forceps and removed through a vascular sheath.

RESULTS

The endobronchial forceps technique was successful in 530 of 537 retrieval attempts on an intention-to-treat basis (98.7%); a total of 530 filters were retrieved. There were 7 failures: (a) 5 failed retrieval attempts (2 that were retrieved successfully in subsequent procedures) and (b) 2 for which retrieval was not attempted. The mean filter dwell time was 1,459 days (SD ± 1,617 days). Laser sheaths were not used for any removal. Filters included herein were 137 Celect (94 Celect and 43 Celect Platinum), 99 Günther Tulip, 72 Option (48 Option and 24 Option Elite), 68 G2, 45 G2X/Eclipse, 42 Denali, 30 OptEase, 29 Recovery, 7 Meridian, and 6 ALN with Hook filters. Thirty-four minor (6.3%) and 11 major (2%) adverse events (AEs) occurred, which did not result in permanent sequelae.

CONCLUSIONS

Use of endobronchial forceps for removal of tip- and strut-embedded retrievable IVC filters is effective and has low AE rates.

STUDY ON THE NONLINEAR DEFORMATION MECHANICAL PROPERTIES OF A NEW TYPE OF VENA CAVA FILTER

In order to analyze the mechanical properties of a new type of retrievable vena cava filter, the Denali and Aeginsy retrievable filters are selected, and the in vivo and in vitro mechanical properties of the three types of retrievable vena cava filters are compared. The nonlinear deformation process of the filter which is pressed into the transport sheath, flicked and released into the vascular vessel is simulated by using the finite element method, and the mechanical behaviors of the filter and the blood vessel wall are analyzed. During the crimping process, the elastic strain peak value of the filter wall increases with increasing amount of grip. The maximum elastic strain peak value of the three filters is less than 8%, and the safety factor is greater than 2, which meets the strength requirement. Equivalent stress and strain on the vascular wall decreases along the direction of blood flow after the filter is opened. The peak value of equivalent stress and strain on the vascular wall corresponding to Aegisy filter is the largest, and the impact on the vascular wall is the largest. The total displacement of the three filters under the action of thrombus and blood fluids is not more than 80[Formula: see text][Formula: see text]m. The impact of the new filter on the vascular wall is smaller than that of Aegisy filter, and the total displacement after implantation is smaller than that of Denali filter. The results are valuable for the evaluation and clinical application of the new vena cava filter.

Vena Cava Filters: Toward Optimal Strategies for Filter Retrieval and Patients' Follow-Up

Mortality rates associated with venous thromboembolism (VTE) are high. Inferior vena cava filters (IVCFs) have been frequently placed for these patients as part of their treatment, albeit the paucity of data showing their ultimate efficacy and potential risk of complications. Issues regarding long-term filter dwell time are accounted for in society guidelines. This topic has led to an FDA mandate for filter retrieved as soon as protection from pulmonary embolism is no longer needed. However, even though most are retrievable, some were inadvertently left as permanent, which carries an incremental lifetime risk to the patient. In the past decade, attempts have aimed to determine the optimal time interval during which filter needs to be removed. In addition, distinct strategies have been implemented to boost retrieval rates. This review discusses current conflicts in indications, the not uncommon complications, the rationale and need for timely retrieval, and different quality improvement strategies to fulfill this aim.

Clinical outcomes of retrievable inferior vena cava filters for venous thromboembolic diseases

Aim: To identify literature evidence assessing retrievable inferior vena cava filter (rIVCF) for venous thromboembolic diseases. Methods: A systematic literature search was conducted to identify relevant references from the mainstay English and Chinese bibliographic databases (search period: January 2003 to October 2019). Results: 80 original studies with 11,413 patients were included in this review. The success rates of deploying the six types of rIVCFs ranged from 98.4 to 100.0%. Denali had the highest retrieval success rate (95.4-97.6%). The incidence rates of fracture and perforation associated with retrieving the six rIVCFs were less than 2%. Conclusion: The approved rIVCF had comparable clinical profiles, except that Denali was easier to be retrieved than other rIVCF.

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.

Spanish multicenter real - life registry of retrievable vena cava filters (REFiVeC)

BACKGROUND

The treatment of venous thromboembolic disease the treatment of choice is systemic anticoagulation. However, the interruption of the inferior vena cava with filters has been recommended when anticoagulation fails or there is a contraindication. Due to the rising inferior vena cava filter (IVCF) complications, physicians are encouraged to retrieve them when there is no longer recommended. In daily practice, it may be a difficult close follow-up of these patients. In this study, the primary objective was to evaluate the IVCF retrieval rate of all implanted filters in a Spanish registry. Secondary objectives were to analyze the causes of failed retrieval, procedure-related complications, and outcomes at a 12-month follow-up.

RESULTS

Three hundred fifty-six vena cava filters were implanted in 355 patients. The types of filter were: Gunther Tulip (Cook Medical) 160 (44.9%), Optease (Cordis) 77 (21.6%), Celect (Cook Medical) 49 (13, 7%), Aegisy (Lifetech Scientific) 33 (9.2%), Option ELITE (Argon Medical devices) 16 (4.4%), Denali filter (BD Bard) 11 (3.08%), ALN filter (ALN) 10 (2.8%). Removal was achieved in 274/356 (76,9%). eighty-two (23,1%) IVCF were not retrieved due to the following: 41 (11,5%) patients required ongoing filtration, 24 IVCF (6,7%) patients died before retrieval, and 17 (4,7%) impossibility of retrieval because of a tilted and embedded filter apex. There were no major complications observed.

CONCLUSIONS

The global retrieval rate of IVCF was achieved in 76.9%, and the adjusted retrieval rate was of 94.15% with no major complications. IVCF tilting was associated with failure of filter removal in less than 5% of cases. This study demonstrates that the retrieval procedure of IVCF is controlled by the clinician and not by the interventional radiologist.

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.

Development of a predictive model for 6 month survival in patients with venous thromboembolism and solid malignancy requiring IVC filter placement

PURPOSE

Our purpose was to develop a predictive model for short-term survival (i.e. <6 months) following inferior vena cava filter placement in patients with venous thromboembolism (VTE) and solid malignancy.

METHODS

Clinical and laboratory parameters were retrospectively reviewed for patients with solid malignancy who received a filter between January 2009 and December 2011 at a tertiary care cancer center. Multivariate Cox proportional hazards modeling was used to assess variables associated with 6 month survival following filter placement in patients with VTE and solid malignancy. Significant variables were used to generate a predictive model.

RESULTS

397 patients with solid malignancy received a filter during the study period. Three variables were associated with 6 month survival: (1) serum albumin [hazard ratio (HR) 0.496, P < 0.0001], (2) recent or planned surgery (<30 days) (HR 0.409, P < 0.0001), (3) TNM staging (stage 1 or 2 vs. stage 4, HR 0.177, P = 0.0001; stage 3 vs. stage 4, HR 0.367, P = 0.0002). These variables were used to develop a predictive model to estimate 6 month survival with an area under the receiver operating characteristic curve of 0.815, sensitivity of 0.782, and specificity of 0.715.

CONCLUSIONS

Six month survival in patients with VTE and solid malignancy requiring filter placement can be predicted from three patient variables. Our predictive model could be used to help physicians decide whether a permanent or retrievable filter may be more appropriate as well as to assess the risks and benefits for filter retrieval within the context of survival longevity in patients with cancer.

Inferior Vena Cava Filters: Current Indications, Techniques, and Recommendations

The vena cava filter (VCF) is intended to prevent the progression of deep venous thrombosis to pulmonary embolism. Recently, the indications for VCF placement have expanded, likely due in part to newer retrievable inferior vena caval filters and minimally invasive techniques. This article reviews the available VCFs, the indications for use, the techniques for placement, and possible outcomes and complications.

Factors associated with reduced radiation exposure, cost, and technical difficulty of inferior vena cava filter placement and retrieval

We sought to delineate factors of inferior vena cava filter placement associated with increased radiation and cost and difficult subsequent retrieval. In total, 299 procedures from August 2013 to December 2014, 252 in a fluoroscopy suite (FS) and 47 in the operating room (OR), were reviewed for radiation exposure, fluoroscopy time, filter type, and angulation. The number of retrieval devices and fluoroscopy time needed for retrieval were assessed. Multiple linear regression assessed the impact of filter type, procedure location, and patient and procedural variables on radiation dose, fluoroscopy time, and filter angulation. Logistic regression assessed the impact of filter angulation, type, and filtration duration on retrieval difficulty. Access site and filter type had no impact on radiation exposure. However, placement in the OR, compared to the FS, entailed more radiation (156.3 vs 71.4 mGy; P = 0.001), fluoroscopy time (6.1 vs 2.8 min; P < 0.001), and filter angulation (4.8° vs 2.6°; P < 0.001). Angulation was primarily dependent on filter type (P = 0.02), with VenaTech and Denali filters associated with decreased angulation (2.2°, 2.4°) and Option filters associated with greater angulation (4.2°). Filter angulation, but not filter type or filtration duration, predicted cases requiring >1 retrieval device (P < 0.001) and >30 min fluoroscopy time (P = 0.02). Cost savings for placement in the FS vs OR were estimated at $444.50 per case. In conclusion, increased radiation and cost were associated with placement in the OR. Filter angulation independently predicted difficult filter retrieval; angulation was determined by filter type. Performing filter placement in the FS using specific filters may reduce radiation and cost while enabling future retrieval.

A case of hepatic, renal and duodenal penetration by a Celect inferior vena caval filter

Inferior vena caval (IVC) filters are used as a mechanical option for the treatment of venous thromboembolism (VTE) when standard anticoagulation therapy is either contraindicated or VTE recurs despite adequate anticoagulation. Filters are not without risk, however. Reported complications include filter migration and fracture of filter components, leading to IVC rupture and penetration into pericaval tissues (notably kidney, heart, pericardium, thoracic cavity, liver, bowel and aorta). Here we describe an extreme case of multiple organ penetration by a standard Celect caval filter.

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.

Inferior Vena Cava Filter Erosion Causing Symptomatic Obstructive Hydronephrosis

Background: Transcaval inferior vena cava (IVC) filter penetration involving the urinary tract is rare, but has been previously reported. We herein present unique management of symptomatic hydronephrosis secondary to erosion of an IVC filter limb into the lumen of the proximal right ureter.

Case Presentation: A 59-year-old woman presented with abdominal and right flank pain in October 2015 and was found to have right hydronephrosis, apparently secondary to obstruction from erosion of an IVC filter limb into the proximal right ureter. This was effectively managed with percutaneous, endovascular, and endourologic procedures, without the need for a major invasive surgical procedure.

Conclusion: Endovascular removal of the IVC filter was performed safely in this case and can be considered when the urinary tract is involved in filter erosion.

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.

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.

Evidence-Based Evaluation of Inferior Vena Cava Filter Complications Based on Filter Type

Many inferior vena cava (IVC) filter types, along with their specific risks and complications, are not recognized. The purpose of this study was to evaluate the various FDA-approved IVC filter types to determine device-specific risks, as a way to help identify patients who may benefit from ongoing follow-up versus prompt filter retrieval. An evidence-based electronic search (FDA Premarket Notification, MEDLINE, FDA MAUDE) was performed to identify all IVC filter types and device-specific complications from 1980 to 2014. Twenty-three IVC filter types (14 retrievable, 9 permanent) were identified. The devices were categorized as follows: conical (n = 14), conical with umbrella (n = 1), conical with cylindrical element (n = 2), biconical with cylindrical element (n = 2), helical (n = 1), spiral (n = 1), and complex (n = 1). Purely conical filters were associated with the highest reported risks of penetration (90-100%). Filters with cylindrical or umbrella elements were associated with the highest reported risk of IVC thrombosis (30-50%). Conical Bard filters were associated with the highest reported risks of fracture (40%). The various FDA-approved IVC filter types were evaluated for device-specific complications based on best current evidence. This information can be used to guide and optimize clinical management in patients with indwelling IVC filters.

Preparation and experimental research into retrievable rapamycin- and heparin-coated vena cava filters: a pilot study

The use of retrievable vena cava filters (RVCFs) was once commonplace, but filter retrieval was often very difficult. Most unsuccessful retrieval was due to intimal hyperplasia of the inferior vena cava and in-filter thrombosis. This pilot study aimed to design a drug-eluting RVCF. The hypothesis was that coated drugs could be released continuously to inhibit vena intimal hyperplasia and thrombosis, and thus improve the retrieval rates of RVCFs. Various concentrations of polycaprolactone (PCL)/chloroform solution were made from a mixture of Rapamycin and Heparin according to the quality of PCL. The drug was coated onto the surface of the filters by a process of dipping. In vitro tests were performed to check stability and in vitro drug release. Animals receiving filter implantation were divided into 4 groups, the experimental intervention group (EI), experimental laparotomy group (EL), control intervention group (CI), and control laparotomy group (CL). Filters were retrieved by laparotomy in the EL and CL groups, and by interventional operation in the EI and CI groups at 10, 20 and 30 days after implantation. Pathological endothelia biopsies were performed with wood grain-eosin (HE) staining and immunohistochemical examination, with the proliferating cell nuclear antigen (PCNA) index, and the results were compared between the experimental and control groups. The weight of thrombus within the filters was also measured by scale and compared. The coating concentration that succeeded in completely covering the surface was 0.2 g/ml. There was better coverage by SEM at this concentration, and the coated drugs had no obvious loss after filter release. The drug release curves showed that the amount of Heparin released was more than 50 % at day 1; Rapamycin released little in the first few days, beginning in earnest at 20 to 30 days. The filters were easy to retrieve at 10 days for both groups, while neither could be retrieved at 30 days. However, at 20 days the filter in the EI group could be retrieved with some difficulty, but the filter in the CI group couldn't be removed at all. The pathological examination and immunohistochemical PCNA examination results showed that the use of drug-eluting filters could effectively inhibit endothelial hyperplasia at 10 and 20 days, but was less effective at 30 days. There was no apparent difference in the total weight of blood clots between the experimental and control groups. We successfully conducted a pilot study into preparing Rapamycin- and Heparin-coated RVCFs. In vitro and in vivo tests further proved the possibility of improving the retrieval rates of RVCFs by effectively inhibiting vein endothelial proliferation, but the anticoagulation and antithrombosis effects of Heparin were unsatisfactory.

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.

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.

Factors affecting Cook Gunther Tulip and Cook Celect inferior vena cava filter retrieval success

OBJECTIVE

Success rates vary for the retrieval of inferior vena cava filters (IVCFs). The optimal retrieval time and factors influencing retrieval success remain unproven. This study aims to determine optimal time and evaluate factors related to successful IVCF retrieval.

METHODS

An institutional prospectively maintained database was reviewed for all IVCF retrieval attempts from 2006 to 2012. Patient demographics, comorbidities, indications for procedure, placement technique, IVCF type, presence of angulation, and time to retrieval were evaluated with respect to success or failure of retrieval. Statistical analyses (t-test, χ(2), correlations, and Kaplan-Meier plots) were performed comparing successful and unsuccessful retrievals.

RESULTS

Of 121 attempted IVCF retrievals, 92 (76%) were successful and 29 (24%) were unsuccessful. There were no significant differences between the successful and unsuccessful attempts in terms of patient demographics, comorbidities, indications for procedure, placement technique, or IVCF type, which included 93 Celect (77%) and 28 Gunther Tulip (23%). Time since IVCF placement was significantly different (P = .025) between the successful and unsuccessful retrieval groups (medians were 105 [7-368] and 162 [43-379] days, respectively). Time since IVCF placement greater than 117 days correlated significantly with unsuccessful IVCF retrieval (R = 0.218; P = .017; odds ratio, 2.88; P = .02). Angulation greater than 20 degrees on anteroposterior radiograph was noted in seven of 29 (24%) unsuccessful retrievals compared with seven of 92 (8%) successful retrievals and was significant (P = .012).

CONCLUSIONS

Cook Gunther Tulip and Celect IVCF retrieval is most likely to be successful within 3 to 4 months of placement. Unsuccessful retrieval attempts are more likely to occur when IVCF position is angulated.

Complications of Celect, Günther tulip, and Greenfield inferior vena cava filters on CT follow-up: a single-institution experience

PURPOSE

To evaluate and compare the rates of complications on follow-up computed tomography (CT) studies of patients with Celect, Günther Tulip, and Greenfield inferior vena cava (IVC) filters.

MATERIALS AND METHODS

Retrospective review of CT studies obtained 0-1,987 days after infrarenal placement of an IVC filter identified 255 Celect, 160 Tulip, and 50 Greenfield filters. Follow-up CT studies were independently evaluated by two observers for IVC perforation, contact with adjacent organs, and filter fracture. Multivariate analysis was performed to identify factors associated with higher rates of IVC perforation, including age, IVC diameter, sex, and history of malignancy.

RESULTS

IVC perforation was observed in 126 of 255 Celect filters (49%) with a mean follow-up of 277 days, 69 of 160 Tulip filters (43%) with a mean follow-up of 437 days, and one of 50 Greenfield filters (2%) with a mean follow-up of 286 days. A significantly higher IVC perforation rate was observed in women (45.5%) compared with men (30.8%; P = .002) and in patients with a history of malignancy (43.7%) compared with patients with no history of malignancy (29.9%; P < .001). Filter fracture was rare, observed in two of 255 Celect filters (0.8%), one of 160 Tulip filters (0.6%), and none of 50 Greenfield filters.

CONCLUSIONS

No significant difference was observed in IVC perforation rate between Celect and Tulip filters. Greenfield filters had a significantly lower rate of IVC perforation than Celect and Tulip filters. Higher IVC perforation rates were observed in women and patients with a history of malignancy.

Retrievable inferior vena cava filters for venous thromboembolism

Inferior vena cava (IVC) filters are used as an alternative to anticoagulants for prevention of fatal pulmonary embolism (PE) in venous thromboembolic disorders. Retrievable IVC filters have become an increasingly attractive option due to the long-term risks of permanent filter placement. These devices are shown to be technically feasible in insertion and retrieval percutaneously while providing protection from PE. Nevertheless, there are complications and failed retrievals with these retrievable filters. The aim of the paper is to review the retrievable filters and their efficacy, safety, and retrievability.

Perforated inferior vena cava filters as the cause of unclear abdominal pain

Inferior vena cava filters are considered a valuable therapeutic option in patients with deep vein thrombosis, subsequent pulmonary emboli, and contraindication for anticoagulation. However, these filters bear the risk of rare but serious complications (e.g., symptomatic caval perforation). We report our experiences with retrievable vena cava filters by means of an actual case and review the recent literature with special regard to filter-dependent delayed symptomatic vena cava perforations. Here, an inferior vena cava filter could be identified as the source of a patient's abdominal pain; after an interventional retrieval approach had failed, open surgical removal became necessary and led to the instant relief of this patient's symptoms. Retrievable vena cava filter removal should be performed in all cases as soon as no longer needed to avoid fatal complications.

Systematic review of the use of retrievable inferior vena cava filters

PURPOSE

To review the available literature on retrievable inferior vena cava (IVC) filters to examine the effectiveness and risks of these devices.

MATERIALS AND METHODS

Investigators searched MEDLINE for clinical trials evaluating retrievable filters and reviewed the complications reported to the Manufacturer and User Facility Device Experience (MAUDE) database of the U.S. Food and Drug Administration (FDA).

RESULTS

Eligibility criteria were met by 37 studies comprising 6,834 patients. All of the trials had limitations, and no studies were randomized. There were 11 prospective clinical trials; the rest were retrospective studies. Despite the limitations of the evidence, the IVC filters seemed to be effective in preventing pulmonary embolism (PE); the rate of PE after IVC placement was 1.7%. The mean retrieval rate was 34%. Most of the filters became permanent devices. Multiple complications associated with the use of IVC filters were described in the reviewed literature or were reported to the MAUDE database; most of these were associated with long-term use (> 30 days). At the present time, the objective comparison data of different filter designs do not support superiority of any particular design.

CONCLUSIONS

In high-risk patients for whom anticoagulation is not feasible, retrievable IVC filters seem to be effective in preventing PE. Long-term complications are a serious concern with the use of these filters. The evidence of the effectiveness and the risks was limited by the small number of prospective studies.

Current status and trends in the treatment of acute pulmonary thromboembolism

Untreated acute pulmonary thromboembolism (APTE) is associated with high mortality, which is reduced by prompt treatment. Anticoagulation is fundamental in the treatment of APTE and should be initiated from suspicion. The efficacy and safety of novel anticoagulant drugs, such as oral anti-Xa and anti-IIa inhibitors, are topics in the treatment of APTE and are now under investigation. Thrombolytic therapy is a widely accepted treatment strategy for massive APTE, but its use for submassive APTE is controversial. Catheter intervention, percutaneous cardiopulmonary support and surgical embolectomy are also necessary and effective for some patients with APTE. A retrievable inferior vena cava filter is preferred for transient protection against APTE. Some studies have demonstrated the feasibility of outpatient treatment in patients with APTE after risk stratification.