Migration of the Günther Tulip Inferior Vena Cava Filter to the Chest

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.

Bundling of Reimbursement for Inferior Vena Cava Filter Placement Resulted in Significantly Decreased Utilization between 2012 and 2014

BACKGROUND

On January 1, 2012, reimbursement for inferior vena cava filters (IVCFs) became bundled by the Centers for Medicare and Medicaid Services. This resulted in ICVF placement (CPT code 37191) now yielding 4.71 relative value units (RVUs), a decrease from 15.6 RVUs for placement and associated procedures (CPT codes 37620, 36010, 75825-26, 75940-26). Our hypothesis was that IVCF utilization would decrease in response to this change as other procedures had done once they had become bundled.

METHODS

Including data from 2010 to 2011 (before bundling) and 2012 to 2014 (after bundling), we utilized 5% inpatient, outpatient, and carrier files of Medicare limited data sets and analyzed IVCF utilization before and after bundling across specialty types, controlling for total diagnosis of deep vein thrombosis (DVT) and pulmonary embolism (PE) (ICD-9 codes 453.xx and 415.xx, respectively) and placement location.

RESULTS

In 2010 and 2011, the rates/10,000 DVT/PE diagnoses were 918 and 1,052, respectively (average 985). In 2012, 2013, and 2014, rates were 987, 877, and 605, respectively (average 823). Comparing each year individually, there is a significant difference (P < 0.0001) with 2012, 2013, and 2014 having lower rates of ICVF utilization. Comparing averages in the 2010-2011 and 2012-2014 groups, there is also a significant decrease in utilization after bundling (P < 0.0001).

CONCLUSIONS

Following the bundling of reimbursement for IVCF placement, procedural utilization decreased significantly. More data from subsequent years will be needed to show if this decrease utilization continues to persist.

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.

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.

Incomplete deployment of the Vena Tech LP filter--case series and concerns

The Vena Tech LP vena cava filter (B Braun, Evanston, Illinois) has been FDA approved since 2001 and is a permanent vena cava filtration device. It replaced the previous Vena tech LGM filter also manufactured by B Braun. The LGM filter had 2 case series reporting a high incidence of incomplete deployment of the filter, especially when placed from a jugular approach. Design changes were made to this device and the LP filter introduced. The LP filter has also been reported to have incompletely deployed both in peer reviewed literature as well as the FDA MAUDE website. We present here 3 cases of incomplete deployment of the Vena Tech LP filter and review the cases previously described as well as attempt to present possible etiologies for incomplete deployment.

Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic thromboembolic pulmonary hypertension: a scientific statement from the American Heart Association

Venous thromboembolism (VTE) is responsible for the hospitalization of >250 000 Americans annually and represents a significant risk for morbidity and mortality. Despite the publication of evidence-based clinical practice guidelines to aid in the management of VTE in its acute and chronic forms, the clinician is frequently confronted with manifestations of VTE for which data are sparse and optimal management is unclear. In particular, the optimal use of advanced therapies for acute VTE, including thrombolysis and catheter-based therapies, remains uncertain. This report addresses the management of massive and submassive pulmonary embolism (PE), iliofemoral deep vein thrombosis (IFDVT),and chronic thromboembolic pulmonary hypertension (CTEPH). The goal is to provide practical advice to enable the busy clinician to optimize the management of patients with these severe manifestations of VTE. Although this document makes recommendations for management, optimal medical decisions must incorporate other factors, including patient wishes, quality of life, and life expectancy based on age and comorbidities. The appropriateness of these recommendations for a specific patient may vary depending on these factors and will be best judged by the bedside clinician.