Diagnosis and treatment of venous thromboembolism and clinical application of inferior vena cava filter in China

High thrombus density ratio on CT venography is associated with inferior vena cava filters trapped embolus in patients with deep vein thrombosis

OBJECTIVE

Defining the appropriate use of retrievable inferior vena cava filters (RIVCF) in patients with deep vein thrombosis (DVT) remains significant clinical need. This study aimed to investigate the association between thrombus density on computed tomography venography (CTV) and RIVCF-trapped embolus to further identify DVT patients who may benefit from RIVCF implantation.

MATERIALS AND METHODS

Between 2019 and 2023, 91 DVT patients with RIVCF implantation were prospectively recruited. CTV was performed for all patients. Based on the presence of RIVCF-trapped embolus at filter retrieval, patients were divided into the no-embolus group and the embolus group. The thrombus density ratio was compared between the two groups. Univariate and multivariate logistic regression models and receiver operating characteristic curve analyses were used to identify the association between thrombus density ratio and RIVCF-trapped embolus.

RESULTS

RIVCF-trapped embolus occurred in 55 patients (60 %). The thrombus density ratio was significantly higher in the embolus group than the no-embolus group (46.23 ± 0.1 % vs. 55 ± 0.08 %, p < 0.001). Logistic regression analysis showed that a high thrombus density ratio was associated with thrombus detachment (OR = 2.36, 95 % CI: 1.29-4.29; p = 0.005). The AUC value of the logistic regression model combined with thrombus density ratio and D-dimer for predicting RIVCF-trapped embolus was 0.882 (p < 0.001), and the thrombus density ratio was 0.841 (95 % CI: 0.75-0.92; p < 0.001).

CONCLUSION

CT-based high thrombus density ratio could predict RIVCF-trapped embolus in DVT patients, indicating that those patients require aggressive RIVCF placement.

CLINICAL RELEVANCE STATEMENT

CT-based high thrombus density ratio was associated with RIVCF-trapped embolus, which can be a potential imaging marker to identify patients who may benefit from RIVCF implantation and may contribute to future improvements of RIVCF application guidelines.

Radiographic Characterization of Inferior Vena Cava and Its Reaction Following Filter Placement: A Single-Center Retrospective Study

OBJECTIVE

To classify the radiographic characterization of the inferior vena cava (IVC) diameter, as well as to quantitatively describe the dimensional alternations in response to variations in filter placement, using cross-sectional computer tomographic venography (CTV) imaging.

METHODS

A single-center retrospective study was conducted on eligible patients who underwent CTV of IVC both before and after the placement of spindle-shaped filters, from September 2018 to June 2023. Baseline data, IVC diameter and orientation pre- and post-filter placement, IVC enlargement rate, and related complications were analyzed.

RESULTS

A total of 70 eligible patients were included, 52 (74.3%) with type 1 IVC, 11 (15.7%) with type 2, 4 (5.7%) with type 3, 3 (4.3%) with type 4, and none with type 5. An accompanying morphological alteration turned IVC into a quasi-round shape with Lin CCC of 0.870, and orientation was significantly altered after filter placement. In patients with type 1, 3, and 4 IVCs, the mean diameter of the IVC increased almost 1.5-fold in the minor axis (95% confidence intervals [CIs]=-7.77 to -5.83, p<0.001), while only a slight expansion of the major axis to its initial size (p>0.05). Greater IVC enlargement rate was seen in the diameter of the minor axis than in the major axis (95% CI=40.31 to 65.12, p<0.001). Notably, regional clots around the filter were found in 22 (31.4%) patients. Among them, 14 (20.0%) were located on the anterior or posterior walls of caval minor axis, 5 (7.1%) in the lateral walls, and 3 (4.3%) in the central part of the IVC filter. Patients exhibited a higher incidence of clots on anterior and posterior walls compared to lateral wall (20.0% vs 7.1%, p=0.014).

CONCLUSION

The morphology of IVC shifted toward an approximated as circles after filter placement, with greater diameter changes seen in the minor axis compared to the major axis, where filter-related thrombosis most occurs.

CLINICAL IMPACT

The findings of this study offer insights into the biomechanical interaction between the inferior vena cava (IVC) and spindle-shaped filters, highlighting the anisotropic dimensional changes triggered by filter placement. The pronounced expansion along the minor axis, where filter-related thrombosis was more frequently observed, underscores a previously underrecognized risk factor for post-implantation complications. These results indicate that perioperative optimization of IVC dimensions and vigilant post-placement monitoring are crucial for improving patient outcomes.

Comparing anticoagulant therapy alone, anticoagulant therapy in combination with catheter-directed thrombolysis, and anticoagulant therapy in combination with pharmacomechanical catheter-directed thrombolysis in the patients with optional inferior vena cava filter-related thrombosis: A single-center retrospective study

OBJECTIVE

To analyze the treatment methods and efficacy of inferior vena cava filter thrombosis (IVCFT).

MATERIALS AND METHODS

In this retrospective study, the clinical data for 47 patients with IVCFT who underwent sequential treatment at the Department of Vascular Surgery, Tianjin Medical University Second Hospital, from January 2020 to January 2023 were analyzed. Patients were divided into three groups according to the treatment method: anticoagulant therapy (AC group), anticoagulation plus catheter-directed thrombolysis (CDT group), and anticoagulation plus AngioJet thrombectomy plus catheter-directed thrombolysis (PCDT group). The evaluation criteria for efficacy mainly included preoperative and postoperative clinical symptoms (Villalta score), thrombus diameter, thrombus clearance rate, filter retrieval rate, filter retention time, and urokinase dosage.

RESULTS

This study included 47 patients, of whom 31 were males (65.9%) and 16 females (34.1%), with a mean age of 72.05 ± 8.32 years. An Aegisy filter was used in seven patients, whereas an Illicium filter was used in forty patients. There were a total of nineteen patients in the anticoagulation-only group, with complete dissolution of the intraluminal thrombus in five patients, a residual thrombus with a maximum diameter ≤1 cm in three patients, and a residual thrombus with a maximum diameter >1 cm in eleven patients. The Villalta score was 7.16 ± 0.6 before treatment and decreased to 3.79 ± 0.59 after treatment. The thrombus diameter decreased from an average of 1.46 ± 0.2 cm before treatment to an average of 0.85 ± 0.14 cm after treatment. The retrieval rate for the filters was 42.11% (8/19), with an average dwell time of 27.4 ± 1.3 days for the filters. The CDT group consisted of 17 patients. Among whom we observed, complete dissolution of the intraluminal thrombus was observed in six patients, residual thrombus with a maximum diameter ≤1 cm in nine patients, and residual thrombus with a maximum diameter >1 cm in two patients. The Villalta score decreased from 7.53 ± 0.83 before treatment to 2.06 ± 0.39 after treatment. The thrombus diameter also decreased from 1.46 ± 0.16 cm before treatment to 0.35 ± 0.11 cm after treatment. The retrieval rate of the filters was 88.24% (15/17), and the average filter indwelling time was 19.25 ± 4.5 days. The PCDT group consisted of 11 patients. We observed complete dissolution of the intraluminal thrombus in four patients, residual thrombus with a maximum diameter ≤1 cm in six patients, and residual thrombus with a maximum diameter >1 cm in one patient. The Villalta score decreased from 7.45 ± 0.76 before treatment to 2.09 ± 0.55 after treatment. The thrombus diameter decreased from 1.50 ± 0.21 cm before treatment to 0.33 ± 0.35 cm after treatment, and the rate of filter retrieval was 90.91% (10/11).

CONCLUSION

The three treatments of anticoagulation therapy, CDT, and PCDT were meaningful for preoperative and postoperative thrombolysis and symptom improvement in patients with IVCFT. The application of CDT and PCDT was superior to anticoagulation therapy, while there was no significant difference between the CDT and PCDT group. The retrieval rate of filters in the anticoagulation therapy group was the lowest, with no significant difference between the CDT and PCDT group.

Unveiling the Link: Minimum Inferior Vena Cava Diameter and Thrombosis Risk

RATIONALE AND OBJECTIVES

This study aimed to investigate the relationship between minimum inferior vena cava (IVC) diameter magnification percentage and in-situ IVC thrombosis (iIVCT) after inferior vena cava filter (IVCF) placement in lower extremity deep vein thrombosis (LEDVT).

METHODS

This was a single center retrospective study. Study sample consisted of patients with LEDVT who received computed tomography venography of IVC both before and after IVCF placement between January 2019 and October 2023. A propensity score matching (PSM) was also used in covariates including age, hypertension, and thrombus limbs. Multivariate Cox regression analyses were performed to mitigate the impact of selection bias and control for potential confounding variables. The incremental changes associated with minimum IVC diameter magnification percentage and iIVCT were evaluated with restricted cubic spines (RCS).

RESULTS

113 LEDVT patients (age 58.8 ± 17.8 years, 57.5% male) were included. Multivariate Cox regression analyses revealed a significant positive association between the minimum IVC diameter magnification percentage and the incidence of iIVCT after adjusting for the age, hypertension, and thrombus limbs (adjusted hazard risk [HR] = 1.02, 95% CI, 1.01 to 1.02, p < .001), suggesting minimum IVC diameter magnification percentage was an independent risk factor for iIVCT. Moreover, after using PSM, the association remained significant (HR=1.01, 95% CI, 1.01 to 1.02, p < .001). RCS analysis showed a non-linear dose-response association (s-shaped fitting curve) between minimum IVC diameter magnification percentage and iIVCT risk (nonlinear p = .041). The fitting curve indicated a threshold effect (overall p = .005), with a smaller magnification percentage being negatively associated with the incidence of iIVCT, presenting continuously decreasing HR at levels of magnification percentage < 37.3%.

CONCLUSION

A decreasing minimum IVC diameter magnification percentage is consistently associated with a decreasing risk of iIVCT following IVCF placement when the percentage is < 37.3%, indicating that it is a protective factor against iIVCT incidence. WHAT THIS PAPER ADDS?: This single-center retrospective study, which designed to investigate the relationship between minimum inferior vena cava diameter magnification percentage and in-situ inferior vena cava thrombosis (iIVCT) following inferior vena cava filter (IVCF) placement in lower extremity deep vein thrombosis in 113 patients, demonstrated that decreasing minimum IVC diameter magnification percentage is consistently associated with a decreasing risk of iIVCT following IVCF placement when the percentage is < 37.3%, indicating that it is a protective factor against iIVCT incidence.

Analysis of risk factors for post-thrombotic syndrome after thrombolysis therapy for acute deep venous thrombosis of lower extremities

Objective

The purpose of the research is to explore post-thrombotic syndrome (PTS) after catheter-directed thrombolysis (CDT) treatment for acute lower extremity deep vein thrombosis (DVT) risk factors.

Methods

We retrospectively selected 171 patients with acute lower extremity DVT undergoing CDT treatment, collected clinical data of the patients, grouped them according to the follow-up results of 1 year after treatment, and included patients with PTS into the concurrent group and patients who did not develop PTS assigned to the unconcurrent group. Univariate analysis and Logistic regression were applied to analyze the risk factors of PTS after catheterization and thrombolytic therapy for acute lower extremity DVT. We applied R4.2.3 software to build three hybrid machine-learning models, including a nomogram, decision tree, and random forest with independent influencing factors as predictive variables.

Results

The incidence of PTS after CDT in acute lower extremity DVT was 36.84 %. BMI >24.33 kg/m2, disease time >7 d, mixed DVT, varicose vein history, stress treatment time>6.5 months, and filter category were independent risk factors for PTS after CDT treatment for acute lower extremity DVT. The AUC value predicted by the random forest model was higher than that of the nomogram model (Z = -2.337, P = 0.019) and the decision tree model (Z = -2.995, P = 0.003).

Conclusion

The occurrence of PTS after CDT treatment of acute lower extremity DVT is closely related to many factors, and the established random forest model had the best effect in predicting PTS complicated with PTS.

Evolving Landscape of Inferior Vena Cava Filter Utilization: A Comprehensive Bibliometric Analysis

This bibliometric analysis scrutinizes the evolution and current challenges in the use of Inferior Vena Cava (IVC) filters, focusing on trends from 2004 to 2023. Analyzing 2470 records, we report the United States' dominant role, with over half of the studies, and a significant shift towards retrievable filters. Despite technological advancements, controversies persist regarding efficacy, safety, and retrieval issues. Our findings point to the need for refined clinical guidelines and enhanced management strategies to navigate the complex landscape of IVC filter utilization effectively.

Characterization and risk factors of inferior vena cava thrombosis in situ detected by computed tomography venography following filter placement: A single-center retrospective cohort study

OBJECTIVE

This study aimed to characterize radiographic characteristics on computed tomography venography and risk factors of inferior vena cava thrombosis (IVCT) in situ after retrievable vena cava filter (VCF) placement.

METHODS

Between September 2018 and June 2023, a single-center retrospective cohort study was conducted in patients with or without IVCT in situ following VCF placement. Patient baseline demographics, presentation of lower extremity deep vein thrombosis (LEDVT), thrombus characteristics, concurrent pulmonary embolism, comorbidities and risk factors for LEDVT, and IVCT and VCF-related information were collected and analysed. Univariable analysis followed by multivariable analysis was performed to evaluate the odds ratio (OR) with a 95% confidence interval (CI).

RESULTS

One hundred and seventeen eligible patients were included, regionally isolated filling-defect surrounding the support pillars of VCF and contacting inferior vena cava (IVC) wall on computed tomography venography images were identified, clots were more frequently found on the minor axis or anterior wall of IVC. Univariable analyses suggested that the incidence of IVCT in situ (31.6%, 37/117) was closely associated with age (P = .001), thrombus limb (left (P = .001) and bilateral side (P = .001)), hypertension (P = .008), filter shapes (P < .001), short IVC diameter (P = .009) or magnification percentage (P = .004), and long IVC diameter (P = .006). Multivariable analyses suggested that bilateral side LEDVT (OR, 4.92; 95% CI, 1.56-15.51; P = .007) and increased short IVC magnification percentage (OR, 1.01; 95% CI, 1.00-1.03; P = .013) statistically significant increase the IVCT in situ risk, whereas increased age (OR, 0.96; 95% CI, 0.94-0.99; P = .013) and short IVC diameter (OR, 0.87; 95% CI, 0.77-0.98; P = .026) were associated with decreased odds against IVCT in situ.

CONCLUSIONS

IVCT in situ represents regionally isolated filling-defect at points of filter contact with IVC wall. Bilateral side LEDVT and increased short IVC magnification percentage may be potential risk factors impacting the occurrence of IVCT in situ, while increased age and short IVC diameter may decrease the incidence of IVCT in situ and seem to be protective factor against IVCT in situ emergence.

A change in strategy for filter choice leads to improved filter retrieval rates

OBJECTIVE

To assess whether a new strategy for the choice of inferior vena cava filter placed would improve filter retrieval rates at our institution.

METHODS

Consecutive patients who underwent retrievable filter placement for temporary embolic protection between January 2021 and January 2023 were considered for study inclusion. Risk factors for nonretrieval of short-term filters were identified in patients receiving filters between January 2021 and January 2022 (prestrategy group). For patients treated between February 2022 and January 2023 (poststrategy group), a long-term filter was recommended for those with these risk factors, and a short-term filter was recommended for those without these risk factors.

RESULTS

The study population included 303 patients (prestrategy group, n = 154; poststrategy group, n = 149). Long-term immobilization (odds ratio [OR] = 38.000; 95% confidence interval [CI]: 6.858-210.564), active cancer (OR = 17.643; 95% CI: 5.462-56.993), and venous thromboembolism detected in the intensive care unit (OR = 28.500; 95% CI: 7.419-109.477) were identified as independent risk factors for nonretrieval of short-term filters. The total retrieval rate was significantly higher in the poststrategy group (87.2%) than in the prestrategy group (72.7%; P = 0.002); the short-term filter retrieval rate was also significantly higher in the poststrategy group (84.5%) than in the prestrategy group (68.5%; P < 0.001).

CONCLUSION

The proposed strategy for filter choice based on risk factors for short-term filter nonretrieval can accurately identify patients who need long-term filter placement while also increasing the retrieval rates for both short-term filters retrieval rates and overall retrieval rates.