First-in-Human Study with Eight Patients Using an Absorbable Vena Cava Filter for the Prevention of Pulmonary Embolism

PurposeTo prospectively evaluate the initial human experience with an absorbable vena cava filter designed for transient protection from pulmonary embolism (PE).Materials and MethodsThis was a prospective, single-arm, first-in-human study of 8 patients with elevated risk of venous thromboembolism (VTE). Seven absorbable IVC filters (made of polydioxanone that breaks down into H₂O and CO₂ in 6 mo) were placed prophylactically before orthopedic (n = 5) and gynecologic (n = 2) surgeries, and 1 was placed in a case of deep vein thrombosis. Subjects underwent CT cavography and abdominal radiography before and 5, 11, and 36 weeks after filter placement to assess filter migration, embolization, perforation, and caval thrombosis and/or stenosis. Potential PE was assessed immediately before and 5 weeks after filter placement by pulmonary CT angiography.ResultsNo symptomatic PE was reported throughout the study or detected at the planned 5-week follow-up. No filter migration was detected based on the fixed location of the radiopaque markers (attached to the stent section of the filter) relative to the vertebral bodies. No filter embolization or caval perforation was detected, and no caval stenosis was observed. Throughout the study, no filter-related adverse events were reported.ConclusionsImplantation of an absorbable vena cava filter in a limited number of human subjects resulted in 100% clinical success. One planned deployment was aborted as a result of stenotic pelvic veins, resulting in 89% technical success. No PE or filter-related adverse events were observed.     

Inferior Vena Cava Filter Litigation Review: An Analysis of Medicolegal Cases Pertaining to Inferior Vena Cava Filters

PurposeTo identify and analyze all medical malpractice and product liability lawsuits pertaining to inferior vena cava (IVC) filters published within a well-recognized legal research database.Materials and MethodsLexisNexis, a legal research database, was used to retrieve cases that mentioned harm from IVC filters, or lack thereof, as the cause for legal action. A total of 672 cases were analyzed for type of case (medical malpractice or product liability), filter model implanted, filter complications, court decisions, and settlement payments if any.ResultsOf 95 analyzed cases, 20 (21.1%) were medical malpractice cases and 75 (78.9%) were product liability cases. C.R. Bard was the manufacturer associated with the most lawsuits (n = 41, 48.8%). The most litigious filters were the G2 filter from C.R. Bard (n = 17, 20.2%) and Greenfield filter from Boston Scientific (n = 17). The most common complications were IVC penetration (n = 26, 29.9%), filter migration (n = 26, 29.9%), filter fracture (n = 23, 26.4%), and tilt (n = 16, 18.4%). The number of product liability cases has increased from accounting for 25.0% (2 of 8) of filter lawsuits between 2000 and 2010 to 83.9% (73 of 87) during 2011–2020. Of the 20 medical malpractice claims, 9 (45%) were filed for failure to place a filter. One physician was found liable for filter-related complications by a state court in 2014.ConclusionsThe majority of recent IVC filter–related lawsuits are filed against manufacturers on the basis of product liability claims, with the main litigious filters being the G2 and Greenfield filters. Most cases resulted in rulings for physicians or manufacturers. Some were filed against physicians for filter-related complications or for failure to place an IVC filter.     

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.     

Stability of Retained Inferior Vena Cava Filter Fragments after Filter Removal

PurposeTo assess the stability and outcome of fractured inferior vena cava (IVC) filter fragments that are retained in patients after IVC filter removal.Materials and MethodsA retrospective analysis was conducted on all patients at a single tertiary referral center between May 2005 and June 2020 with fractured IVC filters where fragment(s) were retained after removal of the main filter body. IVC filter fragment stability was assessed by a clinician review of computed tomography images, chosen from available radiologic studies, to best visualize the fragments. Data collected included filter type, fragment location, duration of fragment follow-up, fragment stability in location, and further fragment fracture or clinical sequelae.ResultsSeventy-seven patients with retained IVC filter fragment(s) after complex filter removal were identified. Of this, 37 patients (14 men, 23 women) were deemed to have adequate imaging follow-up to assess positional stability of the retained fragments, whereas the remainder were excluded from further analysis. Excluding fractured foot processes, 51 separate filter fragments were retrospectively identified and followed for a median duration of 726 days (interquartile range, 843 days; range, 28–3353 days). Filter designs producing the studied fragments included Celect, G2, Recovery, Günther, OptEase, Meridian, and G2X/Eclipse. In all, 50 of 51 (98%) fragments were found to be unchanged in position during their respective intervals of observation. One fragment displayed a rotational change without migrating from its original location. No further fragment fractures or clinical sequelae were observed among the group.ConclusionsWhen asymptomatic, retained IVC filter fragments are predominantly stable and can be safely followed on an intermediate-term basis.     

Thrombotic Risk Associated with Inferior Vena Cava Filter Placement in Patients with Heparin-Induced Thrombocytopenia

PurposeThis study sought to define thromboembolic risk and mortality in patients with heparin-induced thrombocytopenia (HIT) undergoing inferior vena cava filter (IVCF) placement, in light of the American Society of Hematology’s 2018 guidelines against routine use of IVCFs in this population.MethodsA total of 26 patients with HIT who received IVCFs were retrospectively reviewed, and the outcomes of this group were compared with those of 4,707 controls with either HIT or IVCFs alone and with reported outcomes in prior studies.ResultsThe patient group demonstrated 6- and 12-month mortality rates of 26.9% and 30.8%, respectively, which did not differ significantly from those of the control groups and were in line with published mortality rates in the literature. The measured thromboembolic risk of 19.2% in the patient group was also within the range of published rates for patients with HIT or IVCF alone.ConclusionsIVCF placement did not significantly increase the risk of thromboembolism or death in patients with HIT and may be a viable option in the subset of these patients who are not candidates for anticoagulation.     

Analysis of Costs and Payments for Inferior Vena Cava Filter Retrieval in the Medicare Population

Over the past decade, inferior vena cava (IVC) filter retrieval has been increasing, in part due to Food and Drug Administration recommendations and legal pressure. The costs and margin of IVC filter removal are poorly understood. Medicare claims data from 2016 for the 103 highest volume centers for IVC filter retrieval were examined. Pooled mean charges, costs, payments, and margin were calculated by institution. Mean ± SD charges, costs, and payments were $14,138.00 ± $8,400.48, $3,693.28 ± $2,294.27, and $1,949.82 ± $702.91, respectively. Average (range) margin was −$1,706.18 (−$7,509.93 to $362.77). The margin was negative in 99 of the 103 (96%) institutions evaluated. The most significant contributors to the total procedure cost were operating room, supplies, and recovery (44.5%, 23.5%, and 10.4%, respectively). While IVC filter retrieval is often medically indicated, it is typically associated with a financial loss under current reimbursement structure.     

Suprarenal Inferior Vena Cava Filter Placement and Retrieval: Safety Analysis

PurposeTo evaluate safety and retrieval success of retrievable suprarenal inferior vena cava (IVC) filters.Materials and MethodsA retrospective chart review of patients who received a retrievable suprarenal IVC filter between January 2008 and December 2017 was conducted. Suprarenal IVC filters were placed in 24 female and 27 male patients. The most common indications for filter placement were IVC thrombus (n = 20; 39.2%) and iliofemoral venous thrombosis with contraindication to anticoagulation (n = 16; 31.3%). The most common indications for suprarenal placement were IVC thrombus (n = 20; 39.2%), anatomic variants (n = 17; 33.3%), and external IVC compression (n = 8; 15.8%). Duplicated IVC was the most common anatomic variant requiring suprarenal placement (n = 7; 13.7%).ResultsGünther Tulip (n = 40; 78.4%), Denali (n = 10; 19.6%), and Celect (n = 1; 2.0%) filters were used. Retrieval was attempted in 27 of the 51 filters placed (52.9%). Of the 27 attempted retrievals, the technical success rate was 100% (27/27). The median dwell time was 87.0 days (95% confidence interval, 28–137 d). One complication involving fractured struts during filter retrieval occurred. No significant change in craniocaudal filter position, lateral filter tilt, or renal function between placement and retrieval was observed (P < .05). There were no instances of indwelling filter fracture.ConclusionsSuprarenal IVC filters, when indicated, can be placed and retrieved with a low complication rate.     

Deep Learning for Automated Classification of Inferior Vena Cava Filter Types on Radiographs

PurposeTo demonstrate the feasibility and evaluate the performance of a deep-learning convolutional neural network (CNN) classification model for automated identification of different types of inferior vena cava (IVC) filters on radiographs.Materials and MethodsIn total, 1,375 cropped radiographic images of 14 types of IVC filters were collected from patients enrolled in a single-center IVC filter registry, with 139 images withheld as a test set and the remainder used to train and validate the classification model. Image brightness, contrast, intensity, and rotation were varied to augment the training set. A 50-layer ResNet architecture with fixed pre-trained weights was trained using a soft margin loss over 50 epochs. The final model was evaluated on the test set.ResultsThe CNN classification model achieved a F1 score of 0.97 (0.92–0.99) for the test set overall and of 1.00 for 10 of 14 individual filter types. Of the 139 test set images, 4 (2.9%) were misidentified, all mistaken for other filter types that appear highly similar. Heat maps elucidated salient features for each filter type that the model used for class prediction.ConclusionsA CNN classification model was successfully developed to identify 14 types of IVC filters on radiographs and demonstrated high performance. Further refinement and testing of the model is necessary before potential real-world application.     

Prevalence and Characterization of Interaction of Retrievable Inferior Vena Cava Filters with the Spine in Patients Undergoing Complex Filter Removal

PurposeTo examine spinal interaction types and prevalence of inferior vena cava (IVC) filters in patients presenting for complex filter removal.Materials and MethodsThe records of 447 patients presenting for complex removal of IVC filters were reviewed, including patient demographics, IVC filter dwell time, filter fracture status, and computed tomography (CT) evidence of filter interaction with the spine. Spinal interaction was defined as a filter strut touching or penetrating into the vertebral body or disc. Patients with evidence of filter penetration and spinal interaction had abdominal CT that preceded filter removal assessed by 2 interventional radiologists to categorize the type of spinal interaction, including bony reaction and osteophyte formation.ResultsCT evidence of spinal interaction by the filter was found in 18% of patients (80/447). Interaction with the spine was more common in single point of fixation filters than filters with rails (P = .007) and was more likely in filters with round wires than flat wires (P = .0007). Patients with interaction had longer dwell times (mean [SD] 5.7 [4.46] y) compared with patients without interaction (mean [SD] 3.2 [3.85] y); this relationship was significant (P < .0001). Women were more likely than men to experience filter/spine interaction (P = .04). Filters with spinal interaction were more likely to be fractured (P = .001). Filter interaction was found in 38% (30/78) of patients with symptoms, including chest and back pain, compared with 14% (50/369) of patients without symptoms (P < .0001, odds ratio 3.99).ConclusionsRetrievable IVC filters may interact with the spine. These interactions are associated with longer filter dwell times, female sex, and round wire filter construction.     

Magnification Spot Radiographs Improve Assessment for Inferior Vena Cava Filter Fractures prior to Removal Compared to CT

PurposeTo determine if magnification spot radiographs acquired before attempting inferior vena cava (IVC) filter removal have value in the assessment for filter fractures.Materials and MethodsA retrospective review of complex IVC filter removals performed at a tertiary referral center from October 2015 to May 2017 was performed. Magnification spot radiographs (frontal and at least 2 oblique views) were obtained with the fluoroscopic unit in the procedure suite prior to venous access for filter removal. Patients were included in the study if a computed tomography (CT) scan of the abdomen/pelvis before filter removal was available. Ninety-six patients (47 women and 49 men) were included. Most removed filters were the Recovery/G2/G2X/Eclipse/Meridian (n = 28), the Günther Tulip (n = 26), and the Celect/Celect Platinum (n = 22). Blinded review of the pre-procedural CT scans and spot radiographs for the presence of filter fractures was performed by 2 interventional radiologists. Accuracy of each modality was assessed using the status of the explanted filter as the gold standard. Agreement between the 2 readers was assessed with the kappa statistic.ResultsFractures were present in 27 explanted filters (28%). Accuracy of CT was 88% and 68% for readers 1 and 2, respectively, which increased to 98% and 97% with magnification spot radiographs. The kappa statistic was 0.12 for CT and 0.97 for spot radiographs.ConclusionsMagnification spot radiographs acquired before attempting IVC filter removal improve detection of filter fractures and agreement among interventional radiologists. Therefore, these should be performed routinely to allow for optimal treatment planning.     

VenaTech Convertible Vena Cava Filter 6 Months after Conversion Follow-up

PurposeTo report device-related adverse events 6 months after placement or conversion of the VenaTech convertible vena cava filter (VTCF).Materials and MethodsA review of 6-month follow-up data of an investigational device exemption multicenter, prospective, single-arm study was performed. The VTCF was implanted in 149 patients. Conversion was attempted in 64.4% of those patients (n = 96) and successfully in 96.9% of the patients (n = 93). A total of 76 patients completed imaging evaluation at 6 months after filter conversion. Patients who required continued venous thromboembolism prophylaxis at 6 months did not undergo a conversion attempt and were designated as nonconverted filter subjects. A total of 28 nonconverted filter subjects completed imaging evaluation at 6 months after implantation.ResultsEvaluation of patients at 6 months after conversion demonstrated 1 of 76 (1.3%) inferior vena cava (IVC) perforations with a filter strut greater than 3 mm outside of the caval lumen. No cases of recurrent PE, clinically significant filter migration, filter fracture, or IVC thrombosis were reported in the converted subjects. In the nonconverted filter subjects, there was a 14.3% (4 of 28) complete or nearly complete rate of IVC thromboses. There were no cases of recurrent pulmonary embolism, penetration, fracture, or spontaneous conversion in the nonconverted filter subjects. There was a significant reduction in the rate of IVC thrombosis and migration in the converted cohort compared to that in the nonconverted cohort.ConclusionsAt 6 months, the VTCF demonstrated low adverse event rates in the converted configuration, whereas a minority of patients with the nonconverted configuration demonstrated a high risk of IVC thrombosis.     

A Single-Institutional Comparative Analysis of Advanced Versus Standard Snare Removal of Inferior Vena Cava Filters

PurposeTo investigate differences in procedure time, radiation exposure, and periprocedural complications associated with advanced inferior vena cava (IVC) filter retrieval compared with standard snare retrieval.Materials and MethodsA total of 378 patients underwent standard or advanced IVC filter retrieval over a 5-year period. Technical success, retrieval techniques, fluoroscopy time, radiation dose, and complications were analyzed. All retrieval procedures with techniques other than a “snare-and-sheath” method were categorized as advanced, including failed standard attempts requiring intraprocedural conversion to advanced techniques.ResultsA total of 462 filter retrieval attempts were made in 378 patients (57% female). Success rates for standard and advanced retrieval attempts were 86.8% (317 of 365) and 91.8% (89 of 97), respectively. The rate of periprocedural complications was significantly higher in the advanced retrieval group (P = .006). Complication rates for standard and advanced retrievals were 0.6% (2 of 318; all minor) and 5.2% (5 of 97; 3 minor [3.1%] and 2 major [2.1%]), respectively. The 2 major complications during advanced retrievals included filter fracture and embolization. Average fluoroscopy time for advanced retrievals was significantly higher than for standard retrievals (23.1 min vs 4.3 min; P < .001). Average radiation dose for advanced retrievals was also significantly higher than for standard retrievals (557.2 mGy vs 156.9 mGy; P < .001). Use of general anesthesia was also significantly more common in advanced retrievals compared with standard retrievals (6.2% vs 0.9%; P = .002).ConclusionsAdvanced filter retrieval results in a similarly high rate of technical success compared with standard snare retrieval but is associated with greater fluoroscopy time, anesthesia requirements, and radiation exposure.     

Cost Burden and Cost Influencers of Inferior Vena Cava Filter Placement and Retrieval among Medicare Beneficiaries with Acute Venous Thromboembolism

PurposeTo examine the frequency, costs, and cost influencers of inferior vena cava filters (IVCFs) placements and retrievals among a national sample of patients using Medicare data.Materials and MethodsThis retrospective cohort study used the U.S. Medicare 100% database, a nationally representative sample of all U.S. patients aged ≥65 years, from 2014 through 2020. Procedures and clinical characteristics were identified from the diagnosis and procedure codes on Medicare claims. Beneficiaries aged ≥65 years with newly diagnosed venous thromboembolism (VTE) were identified and followed to obtain data on IVCF placements and retrievals. Data on the costs of the index IVCF procedures and any subsequent IVCF placements and retrievals were obtained. Multivariate models were used to estimate the impact of patient and clinical characteristics on costs.ResultsAmong 501,216 patients with newly diagnosed VTE, 4,995 (1%) received an IVCF placement; of these, 1,215 (24.3%) had a retrieval procedure. Beneficiaries with IVCF placements and retrievals differed from a demographic and clinical perspective than from those without. Costs varied by the site of service, VTE acuity, and VTE type. Cost influencers included age, race, census region, service location, and VTE type.ConclusionsIVCF placement costs were driven by baseline patient characteristics (age, race, geographic residence, acute VTE diagnosis, and inpatient site of service), whereas retrieval costs were driven by age and deep vein thrombosis diagnosis. Strategies to mitigate the retrieval costs or the need to retrieve IVCFs may reduce the overall cost burden of IVCFs.     

Randomized Controlled Study of an Absorbable Vena Cava Filter in a Porcine Model

PurposeTo compare the safety and efficacy of an absorbable inferior vena cava (IVC) filter and a benchmark IVC filter in a porcine model.Materials and MethodsA randomized controlled Good Laboratory Practice study was performed in Domestic Yorkshire cross swine. Sixteen swine were implanted with an absorbable IVC filter (test device; Adient Medical, Pearland, Texas); 8 were implanted with a benchmark metal IVC filter (control device; Cook Medical, Bloomington, Indiana). All animals underwent rotational digital subtraction pulmonary angiography and cavography (anteroposterior and lateral) before filter deployment and 5 and 32 weeks after deployment. Terminal procedures and necropsy were performed at 32 weeks. The IVC, heart, lungs, liver, and kidneys were harvested at necropsy. The reported randomized controlled GLP animal study was conducted at Synchrony Labs, Durham, North Carolina.ResultsOne animal died early in the test cohort of a recurring hemorrhage at the femoral access site resulting from a filter placement complication. All other animals remained clinically healthy throughout the study. No pulmonary embolism was detected at the 5- and 32-week follow-up visits. The absorbable filter subjects experienced less caval wall perforation (0% vs 100%) and thrombosis (0% vs 75%). The control device routinely perforated the IVC and occasionally produced collateral trauma to adjacent tissues (psoas muscle and aorta). The veins implanted with the absorbable filter were macroscopically indistinguishable from normal adjacent veins at 32 weeks except for the presence of radiopaque markers. Nontarget tissues showed no device-related changes.ConclusionsImplantation of the absorbable IVC filter in swine proved safe with no pulmonary emboli detected. There was complete to near-complete resorption of the filter polymer by 32 weeks with restoration of the normal appearance and structure of the IVC.     

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

PurposeTo report results of 16 years of using the endobronchial forceps technique to remove embedded inferior vena cava (IVC) filters.Materials and MethodsBetween 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.ResultsThe 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.ConclusionsUse of endobronchial forceps for removal of tip- and strut-embedded retrievable IVC filters is effective and has low AE rates.     

Safety and Efficacy of Percutaneous Translumbar Inferior Vena Cava Catheters: A Systematic Review and Meta-Analysis

PurposeTo examine the reported adverse events associated with inferior vena cava (IVC) catheterization and investigate the reasons for discrepancies between reports.Materials and MethodsCochrane Library trials register, PubMed, Embase, and Scopus databases were systematically searched for studies that included any terms of IVC and phrases related to catheters or central access. Of the 5,075 searched studies, 137 were included in the full-text evaluation. Of these, 37 studies were included in the systematic review, and the adverse events reported in 16 of these 37 identified studies were analyzed. An inverse-variance random-effects model was used to conduct the meta-analysis. Outcomes were summarized by the incidence rate (IR) and 95% CI.ResultsCompared with that of catheters <10 F in size (IR, 0.08; 95% CI, 0.03–0.12), the incidence of catheter-related infections per 100 catheter days was 0.2 more for catheters ≥10 F in size (IR, 0.28; 95% CI, 0.25–0.31). In addition, dual-lumen catheters showed 0.13 more malfunction per 100 catheter days (IR, 0.27; 95% CI, 0.16–0.37) than that shown by single-lumen catheters (IR, 0.14; 95% CI, 0.09–0.19). Both differences were statistically significant. Other adverse events were malposition (IR, 0.04; 95% CI, 0.04–0.05), fracture (IR, 0.01; 95% CI, 0.00–0.02), kinking (IR, 0.01; 95% CI, 0.00–0.01), replaced catheter (IR, 0.2; 95% CI, 0.1–0.31), removal (IR, 0.13; 95% CI, 0.1–0.16), IVC thrombosis (IR, 0.01; 95% CI, 0.00–0.03), and retroperitoneal hematoma (IR, 0.01; 95% CI, 0.00–0.01), all per 100 catheter days.ConclusionsTranslumbar IVC access is an option for patients with exhausted central veins. Small-caliber catheters cause fewer catheter-related infections, and single-lumen catheters function longer.     

Safety and Effectiveness of Advanced Retrieval Techniques for Inferior Vena Cava Filters Compared with Standard Retrieval Techniques: A Systematic Review of the Literature and Meta-Analysis

PurposeTo investigate the pooled safety and effectiveness of advanced retrieval techniques for inferior vena cava (IVC) filters compared with standard retrieval techniques through a systematic review of the literature and meta-analysis.Materials and MethodsA systematic search of retrievable IVC filters between 1980 and 2020 was conducted. Studies were included if both standard and advanced retrieval techniques were utilized in the same cohort, retrieval success rates and adverse event rates were described for each technique, and advanced techniques were employed after the failure of standard techniques. Study heterogeneity was assessed by the I² statistic. The outcomes included retrieval success rates and adverse event rates for standard and advanced retrieval techniques.ResultsOf 1,631 articles, 21 (1%) studies met inclusion criteria. The study heterogeneity was high with an I² of 98%. The pooled random-effects outcomes included an overall standard retrieval success rate of 76% (95% confidence interval [CI], 65%–84%), with minor and major adverse event rates of 1% (95% CI, 0%–1%) and 1% (95% CI, 0%–1%), respectively. The overall pooled advanced retrieval success rates were 90% (95% CI, 82%–94%), with minor and major adverse event rates of 5% (95% CI, 2%–9%) and 4% (95% CI, 2%–6%), respectively. The standard retrievals were 16% less likely (risk ratio) to be successful (95% CI, 32% less likely to 4% more likely; P = .11). The major and minor adverse event rates were 88% and 84% less likely in standard retrievals compared with advanced retrievals, respectively (95% CI, 86%–94%; P < .0001; 95% CI, 70%–91%; P < .0001).ConclusionsAdvanced retrieval techniques for IVC filters permit a higher retrieval success rate with low adverse event rates in cases of standard retrieval failure.     

Ultrasound-Accelerated,Catheter-Directed Thrombolysis for Submassive Pulmonary Embolism: Single-Center Retrospective Review with Intermediate-Term Outcomes

PurposeTo evaluate ultrasound-accelerated, catheter-directed thrombolysis (CDT) for treatment of acute submassive pulmonary embolism (PE).Materials and MethodsThis single-center, retrospective study included patients who underwent CDT for acute submassive PE (N = 113, 52% men/48% women) from 2013 to 2017. Baseline characteristics included history of deep venous thrombosis (12%), history of PE (6%), and history of cancer (18%). Of cohort patients, 88% (n=99) had a simplified PE severity index score of ≥ 1 indicating a high risk of mortality.ResultsA technical success rate of 100% was achieved with 84% of patients having bilateral catheter placements. Average tissue plasminogen activator (tPA) therapy duration was 20.7 hours ± 1.5, and median tPA dose was 21.5 mg. Three patients (2.6%) experienced minor hemorrhagic complications. Mean hospital length of stay was 6 days. Mean pulmonary arterial pressure decreased from 55 mm Hg on presentation to 37 mm Hg (P < .01) 1 day following initiation of thrombolytic therapy. All-cause mortality rate of 4% (n = 4) was noted on discharge, which increased to 6% (n = 7) at 6 months. At 6-month follow-up compared with initial presentation, symptom improvements (93%), physiologic improvements (heart rate 72 beats/min vs 106 beats/min, P < .01), oxygen requirement improvements (fraction of inspired oxygen 20% vs 28%, P < .01), and right ventricular systolic pressure improvements by echocardiography (30 mm Hg vs 47 mm Hg, P < .01) were observed.ConclusionsCDT for acute submassive PE was associated with low complications and mortality, decreased right ventricular systolic pressure, high rates of clinical improvement, and improved intermediate-term clinical outcomes.