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PurposeTo create an algorithm able to accurately detect IVC filters on radiographs without human assistance, capable of being used to screen radiographs to identify patients needing IVC filter retrieval.MethodsA primary dataset of 5225 images, 30% of which included IVC filters, was assembled and annotated. 85% of the data was used to train a Cascade R-CNN (Region Based Convolutional Neural Network) object detection network incorporating a pre-trained ResNet-50 backbone. The remaining 15% of the data, independently annotated by three radiologists, was used as a test set to assess performance. The algorithm was also assessed on an independently constructed 1424-image dataset, drawn from a different institution than the primary dataset.ResultsOn the primary test set, the algorithm achieved a sensitivity of 96.2% (95% CI 92.7-98.1%) and a specificity of 98.9% (95% CI 97.4-99.5%). Results were similar on the external test set: sensitivity 97.9% (95% CI 96.2-98.9%), specificity 99.6 (95% CI 98.9-99.9%).ConclusionFully automated detection of IVC filters on radiographs with high sensitivity and excellent specificity required for an automated screening system can be achieved using object detection neural networks. Further work will develop a system for identifying patients for IVC filter retrieval based on this algorithm.

Inferior vena cava (IVC) filters are posited to effect flow dynamics, causing turbulence, vascular remodeling and eventual thrombosis; however, minimal data exists evaluating hemodynamic effects of IVC filters in vivo. The purpose of this study was to determine differences in hemodynamic flow parameters acquired with two-dimension (2D)-perfusion angiography before and after IVC filter placement or retrieval. 2D-perfusion images were reconstructed retrospectively from digital subtraction angiography from a cohort of 37 patients (13F/24M) before and after filter placement (n = 18) or retrieval (n = 23). Average dwell time was 239.5 ± 132.1 days. Changes in the density per pixel per second within a region of interest (ROI) were used to calculate contrast arrival time (AT), time-to-peak (TTP), wash-in-rate (WIR), and mean transit time (MTT). Measurements were obtained superior to, inferior to, and within the filter. Differences in hemodynamic parameters before and after intervention were compared, as well as correlation between parameters versus filter dwell time. A P value with Bonferroni correction of <.004 was considered statistically significant. After placement, there was no difference in any 2D-perfusion variable. After retrieval, ROIs within and inferior to the filter showed a significantly shorter TTP (1.7 vs 1.4 s, P = .004; 1.5 vs 1.3 s, P = .001, respectively) and MTT (1.7 vs 1.4 s, P = .003; 1.5 vs 1.2 s, P = .002, respectively). Difference in variables showed no significant correlation when compared to dwell time. 2D-perfusion angiography is feasible to evaluate hemodynamic effects of IVC filters in vivo. TTP and MTT within and below the filter after retrieval were significantly changed, without apparent correlation to dwell time, suggesting a functional hemodynamic delay secondary to filter presence.

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A 47-year-old male with a remote renal transplant due to pediatric glomerulonephritis on oral anticoagulation for symptomatic deep venous thrombosis and pulmonary emboli presented with sudden hip and groin pain. The patient was found to have a spinal epidural hematoma, underwent reversal of anticoagulation, and subsequently developed worsening renal function. Imaging revealed occlusive iliocaval venous thrombosis with extension to the renal allograft. Given risk of epidural hematoma expansion, the patient was deemed high risk for thrombolysis. The AngioVac system was used for single session thrombus removal. The patient's renal function improved and no focal neurologic sequelae was noted postprocedure. Six-month follow-up showed persistent vessel patency.

BackgroundFew studies have evaluated the use and outcomes of inferior vena cava filters (IVCF) insertion in cancer patients with deep venous thrombosis (DVT) or pulmonary embolism (PE).MethodsHospital records of patients with a principal diagnosis of lower extremity DVT and/or PE and cancer in California between January 1, 2005 and December 31, 2009 were analyzed. Multivariable logistic regression analysis was used to identify variables associated with IVCF use and propensity matched methodology was used to determine the effect of IVCF insertion on clinical outcomes.ResultsAn IVCF was placed in 19.6% of 14,000 cancer patients and VTE. This varied widely across hospitals, from 0% to 52%, and by cancer type. The strongest predictors of IVCF use were a diagnosis of brain cancer (OR=4.6, CI: 3.7-5.6), undergoing major surgery (OR=4.9, CI: 3.9-6.1), and bleeding (OR=2.7, CI: 2.0-3.5). Only 21% of patients with IVCF had a strong contraindication to anticoagulation (bleeding or major surgery). There was no benefit for 30-day mortality and no reduction in subsequent PE (+/-DVT). Additionally, there was 60% increased risk of recurrent DVT and 20% increased risk of subsequent bleeding when an IVCF was placed.ConclusionsAn IVCF was placed in approximately 20% of acute VTE patients with cancer and use varied widely between hospitals and cancer types. Most patients did not have a contraindication for anticoagulation. There was no benefit in short-term mortality or risk of PE; there was increased risk of DVT and subsequent bleeding.

BackgroundFew studies have evaluated the use and outcomes of inferior vena cava filters (IVCF) insertion in cancer patients with deep venous thrombosis (DVT) or pulmonary embolism (PE).MethodsHospital records of patients with a principal diagnosis of lower extremity DVT and/or PE and cancer in California between January 1, 2005 and December 31, 2009 were analyzed. Multivariable logistic regression analysis was used to identify variables associated with IVCF use and propensity matched methodology was used to determine the effect of IVCF insertion on clinical outcomes.ResultsAn IVCF was placed in 19.6% of 14,000 cancer patients and VTE. This varied widely across hospitals, from 0% to 52%, and by cancer type. The strongest predictors of IVCF use were a diagnosis of brain cancer (OR=4.6, CI: 3.7-5.6), undergoing major surgery (OR=4.9, CI: 3.9-6.1), and bleeding (OR=2.7, CI: 2.0-3.5). Only 21% of patients with IVCF had a strong contraindication to anticoagulation (bleeding or major surgery). There was no benefit for 30-day mortality and no reduction in subsequent PE (+/-DVT). Additionally, there was 60% increased risk of recurrent DVT and 20% increased risk of subsequent bleeding when an IVCF was placed.ConclusionsAn IVCF was placed in approximately 20% of acute VTE patients with cancer and use varied widely between hospitals and cancer types. Most patients did not have a contraindication for anticoagulation. There was no benefit in short-term mortality or risk of PE; there was increased risk of DVT and subsequent bleeding.

BackgroundFew studies have evaluated the use of vena cava filters (VCF) in cancer patients with acute venous thromboembolism (VTE).MethodsHospital discharge records of patients who were admitted with a principal diagnosis of lower extremity deep-vein thrombosis or pulmonary embolism and cancer in California between January 1, 2005 and December 31, 2009 were analyzed. Multivariable logistic regression analysis was used to identify variables associated with VCF use.ResultsA VCF was placed in 2747 (19.6%) of 14,000 cancer patients. The percentage of patients treated with a VCF varied widely across hospitals, from 0% to 52% (mean=19.2%, median=17.2%), and by cancer type, ranging from 8% for lip/oral to 43% for brain. Using multivariable analysis, the strongest predictors of VCF use were a diagnosis of brain cancer (OR=4.6, CI: 3.7 -5.6), undergoing major surgery (OR=4.9, CI: 3.9 -6.1), and bleeding (OR=2.7, CI: 2.0-3.5). Other factors significantly associated with VCF insertion included hospital characteristics (larger, urban and private), and greater severity-of-illness at the time of admission. Only 1083 (7.7%) of patients had an absolute contraindication to anticoagulation (bleeding or surgery).ConclusionsA VCF was deployed in approximately 20% of acute VTE patients with cancer, but use varied widely between hospitals and cancer types. The strongest risk factors were undergoing surgery, active bleeding, and having brain cancer. Only 21% of VCF treated cancer patients had a strict contraindication to anticoagulation therapy. Further research is needed to determine if VCF use is of any benefit in cancer patients with acute VTE.

BackgroundFew studies have evaluated the use of vena cava filters (VCF) in cancer patients with acute venous thromboembolism (VTE).MethodsHospital discharge records of patients who were admitted with a principal diagnosis of lower extremity deep-vein thrombosis or pulmonary embolism and cancer in California between January 1, 2005 and December 31, 2009 were analyzed. Multivariable logistic regression analysis was used to identify variables associated with VCF use.ResultsA VCF was placed in 2747 (19.6%) of 14,000 cancer patients. The percentage of patients treated with a VCF varied widely across hospitals, from 0% to 52% (mean=19.2%, median=17.2%), and by cancer type, ranging from 8% for lip/oral to 43% for brain. Using multivariable analysis, the strongest predictors of VCF use were a diagnosis of brain cancer (OR=4.6, CI: 3.7 -5.6), undergoing major surgery (OR=4.9, CI: 3.9 -6.1), and bleeding (OR=2.7, CI: 2.0-3.5). Other factors significantly associated with VCF insertion included hospital characteristics (larger, urban and private), and greater severity-of-illness at the time of admission. Only 1083 (7.7%) of patients had an absolute contraindication to anticoagulation (bleeding or surgery).ConclusionsA VCF was deployed in approximately 20% of acute VTE patients with cancer, but use varied widely between hospitals and cancer types. The strongest risk factors were undergoing surgery, active bleeding, and having brain cancer. Only 21% of VCF treated cancer patients had a strict contraindication to anticoagulation therapy. Further research is needed to determine if VCF use is of any benefit in cancer patients with acute VTE.

To describe the drugs used to treat venous thromboembolism (VTE) and to review particular aspects of the management (elastic stockings, thrombolysis, thrombectomy, vena cava filter)., Journal Article, Review, SCOPUS: re.j, info:eu-repo/semantics/published

To describe the drugs used to treat venous thromboembolism (VTE) and to review particular aspects of the management (elastic stockings, thrombolysis, thrombectomy, vena cava filter)., Journal Article, Review, SCOPUS: re.j, info:eu-repo/semantics/published

The authors tested in vitro nine caval filters to evaluate clot-trapping capacity and transfilter pressure gradients under varying experimental conditions. The filtering efficiency of the stainless-steel Greenfield filter was evaluated in a modified flow model. A total of 2,100 clots were injected. In addition, controlled parameters simulating in vivo conditions were selected to appreciate clot-trapping capacity and pressure gradients for nine filters in horizontal and vertical positions, by using small (3 x 30 mm) and medium-sized (5 x 30 mm) clots. Statistical evaluation was performed for 3,600 clot deliveries. Depending on experimental conditions, the clot-trapping capacity of the Greenfield filter varied greatly (0%-78%) by using small and medium clots. Bird's Nest and Simon nitinol filters demonstrated the highest filtering efficiency (94%-100%) for small clots. Medium clots were effectively captured by Bird's Nest, Simon nitinol, Antheor, and Günther Tulip filters (79%-100%). Experimental parameters influence a filter's clot-trapping capacity. Bird's Nest filters demonstrated the highest clot-trapping capacity.