Abstract
Background
Inferior vena cava filter (IVCF) is used to prevent pulmonary embolism (PE) due to deep vein thrombosis (DVT), and some filters are indwelling for a long time, which increase the risk of thrombotic events. Single-channel anticoagulation is still inadequate in the prevention of thrombosis. This study aims to explore the efficacy and safety of rivaroxaban combined with aspirin versus rivaroxaban alone in the prevention of thrombotic events in patients with long-term IVCF implantation.
Methods
A retrospective analysis was conducted on patients with long-term IVCF implantation in the two centers from August 2021 to October 2024. Among them, 58 cases were in the single-channel (SC) group, who only took rivaroxaban orally after surgery, and 61 cases were in the dual-channel (DC) group, who took rivaroxaban and aspirin orally after surgery. The follow-up period was 12 months. The primary endpoint was the incidence of combined venous thromboembolism (VTE). The secondary endpoints were the recurrence rate of lower extremity DVT, the incidence of IVCF thrombosis (IVCFT), PE, and adverse events, Venous Clinical Severity Score (VCSS) and Chronic Venous Insufficiency Questionnaire (CIVIQ-20).
Results
The incidence of combined VTE in Group SC (14/58, 24.1%) was higher than that in Group DC (6/61, 9.8%) (HR: 0.38, 95% CI: 0.14-0.98, P=0.037). The incidence of IVCFT, VCSS and CIVIQ-20 at 12 months in Group SC were higher than those in Group DC. There were no significant differences in the incidence of DVT recurrence, PE, bleeding-related adverse events, and all-cause mortality between the two groups.
Conclusion
For patients with long-term IVCF implantation, compared with rivaroxaban alone, the dual-channel inhibition of rivaroxaban combined with aspirin may reduce the occurrence of thrombotic events, alleviate clinical symptoms and improve the quality of life of patients, without increasing the risk of adverse events such as bleeding.
Introduction
Anticoagulation was established as the first-line standard therapy for venous thromboembolism (VTE). While, inferior vena cava filter (IVCF), as the key interventional device for mechanical prevention of pulmonary embolism (PE) caused by the lower extremity deep venous thrombosis (DVT), was indicated for patients with contraindications to anticoagulation, failure of anticoagulation, or high risk of PE.1,2 Currently, clinical guidelines prefer the implantation of retrievable IVCF over permanent IVCF, aiming for planned retrieval once the high-thrombosis-risk period resolves. 3 However, real-world retrieval rates remain suboptimal globally, with pooled real-world studies reporting an average retrieval rate of approximately 30%, and notable variability across different registries and healthcare centers.4,5 An IVCF that failed to be retrieved within the recovery window period, typically having been implanted for over 12 months, was defined as long-term IVCF implantation. The risk factors of long-term IVCF indwelling mainly include malignant tumors, advanced age, failure of retrieval, etc. 6 Thrombotic events, including DVT recurrence, IVCF thrombosis (IVCFT), and PE, among others, represent the primary complications associated with long-term IVCF implantation. 7 Studies have shown that in the event that the retrievable filter fails to be retrieved within the recovery window time, the risk of thrombosis escalates notably with the prolongation of implantation time.8-10 Nevertheless, single-channel anticoagulant therapy still exhibits shortcomings in reducing the incidence of thrombotic events associated with IVCF. The incidence of recurrent thrombosis among patients receiving IVCF treatment under anticoagulation ranges from approximately 12% to 36%.11-14 In recent years, dual-channel inhibition of anticoagulation plus antiplatelet has offered a potent novel alternative for the prevention of thrombotic events in patients with high-risk pan-vascular diseases. It exerts its effect by concurrently intervening in two crucial pathways of thrombosis: the platelet aggregation pathway and the coagulation cascade pathway. 15 To the best of our knowledge, the efficacy of rivaroxaban combined with aspirin dual-channel inhibition in patients with long-term IVCF implantation has not been reported previously. Based on the aforementioned information, the purpose of this study was to evaluate the efficacy and safety of rivaroxaban combined with aspirin in the prevention of thrombotic events in patients with long-term IVCF implantation.
Materials and Methods
Patients
A retrospective cohort study was conducted on patients who were on long-term implantation with IVCF at two large tertiary hospitals in China between August 2021 and October 2024. These patients were selected based on the inclusion and exclusion criteria set for the study. Inclusion criteria: (1) Age ≥ 18 years old; (2) IVCF implantation time ≥ 12 months (defined as “long-term implantation”), with 12 months follow-up; (3) Rivaroxaban or a combination of rivaroxaban and aspirin was regularly administered in accordance with the doctor’s instructions; (4) Complete clinical data (operation records, medication records, imaging reports, follow-up records, etc.). All clinical data in this study were obtained from the inpatient electronic system, outpatient records, and telephone follow-up records. Exclusion criteria: (1) Identify contraindications to anticoagulation [such as active bleeding, coagulopathy (platelet count < 50×109/L or fibrinogen < 1 g/L), severe liver and kidney dysfunction (alanine aminotransferase or aspartate aminotransferaseor > 150 U/L, or international normalized ratio > 1.5, or stage 4-5 chronic kidney disease), etc]. (2) Other anticoagulant/antiplatelet drugs were uesd in combination. Flowchart of the study (Figure 1). This study was approved by the ethics committee of our medical institution [Institutional Review Board (IRB) Approval: 2023LLWL022] on January 22, 2026. Given the retrospective nature of this study, the requirement for informed consent was waived. This study was conducted in accordance with the Helsinki Declaration of 1975, as revised in 2024. We have de-identified all patient details. The reporting of this study conforms to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines.
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Flowchart of the study. DC: dual-channel; IVCF: inferior vena cava filter; SC: single-channel
Experimental Procedure
All participants underwent IVCF implantation for the following established indications: acute lower extremity DVT with high risk of PE (floating thrombosis in iliofemoral vein segment), acute lower extremity DVT for catheter-directed thrombolysis (CDT) or percutaneous mechanical thrombectomy (PMT). Notably, patients with anticoagulation contraindications were excluded according to the predefined exclusion criteria. Based on individual clinical indications, CDT or PMT was performed as adjunctive therapy. Starting from the first day after the operation, in the single-channel (SC) group, rivaroxaban was administered at a loading dose of 15 mg twice daily for the first 21 days, followed by a maintenance dose of 20 mg once daily. The dual-channel (DC) group received, in addition to Group SC regimen, enteric-coated aspirin at a daily dose of 100 mg.
Materials
Rivaroxaban (manufacturer: Guangdong Dongyang, approval number: H20213374). Aspirin enteric-coated tablets (manufacturer: Shenyang Ogina, approval number: H20065051). The IVCF types implanted included Aegisy (specifications: XJLX3260), Optease (specifications: 466-F210A), Denali (specifications: DL950F), and Celect (specifications: IGTCFS-65).
Follow up and Study Endpoints
Lower extremity venous color Doppler ultrasound was performed on postoperative day 1 to assess treatment efficacy (e.g., thrombus resolution, flow characteristics). Patients were followed up by imaging examinations at 3-month intervals from the first day after surgery, and medication adherence was guided by outpatient or telephone follow-up, with a total follow-up duration of 12 months. The primary endpoint was the incidence of conbined VTE, defined as any of the following adjudicated events: (1) Recurrent lower extremity DVT, the recurrence of DVT was assessed by comparing colour Doppler ultrasound findings of the lower extremity veins on the first postoperative day to determine any recurrence or progression of DVT during the follow-up period; (2) IVCFT, confirmed by imaging modalities including abdominal ultrasound, contrast-enhanced Computed Tomography (CT), or venography; (3) Non-fatal or fatal PE, confirmed by Computed Tomography Pulmonary Angiography (CTPA).
The secondary endpoints were the recurrence rate of DVT, the incidence of IVCFT, the incidence of PE, the incidence of bleeding related adverse events, all-cause mortality, the Venous Clinical Severity Score (VCSS) and Chronic Venous Insufficiency Questionnaire (CIVIQ-20). Among them, bleeding-related adverse events were classified according to the standards set forth by the International Society on Thrombosis and Haemostasis (ISTH), 17 which categorises them into major bleeding, clinically relevant non-major bleeding, and minor bleeding. The VCSS and CIVIQ-20 were employed to evaluate patients’ long-term venous symptoms and quality of life. VCSS was evaluated on the first postoperative day and at the 12 months follow-up post-operation and comprised ten assessment items, including pain, oedema, venous claudication, pigmentation, lipid scleroderma, ulcers, ulcer diameter, disease stage, recurrence, and quantity. Each item received a score ranging from 0 to 3 points, yielding a total score between 0 and 30 points; a higher score indicates a more severe condition. 18 CIVIQ-20 was evaluated at the 12 months follow-up post-operation and encompassed four domains: social, psychological, physical, and pain, consisting of 20 sub-items. Each sub-item was scored on a five-point scale, ranging from 1 to 5 points, reflecting severity from mild to severe. The score for each domain was calculated by summing the scores of its constituent sub-items, resulting in a total score that ranges from 0 to 100 points. A lower total score signified a higher quality of life. 19
Statistical Methods
Data were analysed using SPSS version 25.0 and R version 4.3 statistical software. Continuous variables were presented as mean ± standard deviation (SD), with the t-test employed for group comparisons. Categorical variables were reported as n (%), and the χ2 test was utilised for intergroup comparisons. The incidence of conbined VTE, the recurrence rate of DVT, the incidence of IVCFT, the occurrence of bleeding related adverse events, and all-cause mortality were calculated using the Kaplan-Meier method. The Log-rank test was applied for group comparisons. For time-to-event outcomes, Cox proportional hazards regression was employed to calculate the hazard ratio (HR) and 95% confidence interval (CI) between the two groups, and Group SC was used as the reference comparison. For VCSS, analysis of covariance (ANCOVA) was performed to compare the 12 months VCSS between groups, adjusted for baseline VCSS to account for potential baseline imbalance. P value < 0.05 was deemed statistically significant.
Results
Demographic Characteristics
Comparison of Baseline Characteristics Between the Two Groups [n (%) ]
CDT: catheter-directed thrombolysis; DC: dual-channel; IVCF: inferior vena cava filter; PE: pulmonary embolism; PMT: percutaneous mechanical thrombectomy; SC: single-channel; SD: standard deviation; VTE: venous thromboembolism.
Primary Outcome
Comparison of Primary and Secondary Endpoints [n (%) ]
CI: confidence interval; DC: dual-channel; DVT: deep vein thrombosis; HR: hazard ratio; IVCFT: inferior vena cava filter thrombosis; PE: pulmonary embolism; SC: single-channel; VTE: venous thromboembolism.

Kaplan-Meier analysis of event-free survival for combined VTE (A) and IVCFT (B). CI: confidence interval; DC: dual-channel; HR: hazard ratio; IVCFT: inferior vena cava filter thrombosis; SC: single-channel; VTE: venous thromboembolism; %: percentage
Secondary Outcomes
Comparison of VCSS and CIVIQ-20 (Mean ± SD)
CIVIQ-20: Chronic Venous Insufficiency Questionnaire; DC: dual-channel; SC: single-channel; SD: standard deviation; VCSS: Venous Clinical Severity Score; n: number of patients.
Discussion
This study revealed that, when comparing single-channel inhibition in Group SC, dual-channel inhibition in Group DC may offer advantages in reducing the incidence of combined VTE, particularly the incidence of IVCFT, without an increase in the risk of adverse events such as bleeding. Furthermore, dual-channel inhibition was associated with lower scores on VCSS and CIVIQ-20.
Thrombotic events represent one of the primary complications among patients with long-term IVCF implantation. 20 In this study, the incidence of combined VTE in Group SC and Group DC were 24.1% and 9.8%, respectively. Previous studies have confirmed that the metallic framework of the IVCF itself serves as a significant catalyst for thrombus formation; its surface disrupts laminar blood flow, induces endothelial injury, and activates the coagulation cascade.21,22 Numerous studies have established a strong positive correlation between the incidence of filter-induced thrombosis and the duration of indwelling time.23,24 A multicentre retrospective study revealed that the overall incidence of IVCFT in lower extremity DVT patients treated with IVCF within the first 30 days of filter indwelling was 32.58%, even in the presence of anticoagulation. 25 The COMMAND VTE Registry Study carried out a long-term follow-up on 2,626 patients suffering from acute VTE. 26 The results indicated that patients with long-term IVCF implantation (73.2% undergoing continuous anticoagulation) were associated with an elevated adjusted risk of DVT recurrence in comparison with those not using IVCF (55.7% undergoing continuous anticoagulation) (HR: 2.27, 95% CI: 1.43-3.60). Compared with non-cancer patients, cancer patients had a higher risk of DVT recurrence (HR: 2.47, 95% CI: 1.24-4.91). Of greater concern was the fact that such thrombosis is not an isolated occurrence; it might propagate to the proximal end, resulting in complete occlusion of the inferior vena cava, or it might detach at the distal end, precipitating a fatal PE.27,28
In the prevention and treatment of VTE, direct oral anticoagulants (DOACs) have emerged as the first-line medication of choice.29,30 Their advantages were not limited to the absence of a requirement for routine monitoring of coagulation parameters, minimal drug interactions, and rapid onset of action; they also possessed pharmacokinetic characteristics that align closely with the time-sensitive nature of filter management.31-33 Numerous retrospective cohort studies and meta-analyses have demonstrated that the efficacy and safety of rivaroxaban anticoagulation are non-inferior to those of warfarin in patients with IVCF implantation.34,35 Nevertheless, due to improved medication adherence, the actual treatment target attainment rate in the rivaroxaban group was markedly superior to that in the warfarin group. However, patients with long-term IVCF implantation frequently presented with more complex conditions and a heightened risk of thrombosis recurrence, rendering the single-channel inhibition of DOACs often limited in efficacy.20,25 From a pathophysiological standpoint, IVCF, as an intravascular foreign body, could activate the endogenous coagulation system on its surface, thereby promoting platelet adhesion and aggregation. This activation simultaneously increases the risk of thrombotic events, including the recurrence of DVT and IVCFT.36,37 Simple anticoagulation, such as rivaroxaban, primarily inhibited thrombin production and fibrin formation, 38 proving more effective in preventing DVT recurrence. Antiplatelet agents, such as aspirin, diminished thromboxane A2 production by inhibiting cyclooxygenase-1 (COX-1), 39 and might be more efficacious in addressing local thrombosis resulting from endothelial injury to the vena cava. Consequently, the recurrence rate of DVT in Group SC was comparable to that in Group DC (12.1% vs 8.2%), while the incidence of IVCFT in Group SC was notably higher than that in Group DC (10.3% vs 1.6%). Theoretically, dual-channel inhibition may provide a more comprehensive approach to suppressing filter-related thrombotic events through dual pathways.
Irrespective of whether it is single-channel or dual-channel inhibition, safety (e.g., bleeding risk) represented one of the critical considerations in clinical drug management. The ARIVA trial assessed the efficacy and safety of aspirin combined with rivaroxaban compared to rivaroxaban in patients with the post-thrombotic syndrome who were undergoing venous stenting. 40 The incidence of clinically relevant non-major bleeding was 8.2% (7/85) in the dual-drug group and 2.4% (2/84) in the single-drug group (P=0.17). Minor bleeding occurred in 7.1% (6/85) of the dual-drug group and 6.0% (5/84) of the single-drug group (P=1.00). In this study, only 5 cases of minor bleeding were reported, comprising 3.4% (2/58) in Group SC and 4.9% (3/61) in Group DC, again with no statistical difference between the two groups. These findings were consistent with previous studies and further substantiate that dual-channel inhibition does not elevate the risk of bleeding events.
Long-term IVCF implantation exerts an impact on hemodynamics. 26 In the event that subsequent IVCF-related thrombotic events transpire, it may result in chronic partial or complete obstruction of the inferior vena cava, giving rise to persistent venous hypertension, which subsequently initiates a series of downstream cascades. These effects included severe edema in both lower extremities, skin lipid sclerosis, pigmentation changes, venous ulcers, and venous claudication in up to 30% of patients. The latter was characterised by heavy, distending pain and fatigue in the lower limbs following ambulation, significantly impairing quality of life.41,42 In this study, the VCSS and CIVIQ-20 of Group SC at 12 months were both higher than those of the Group DC, with the CIVIQ-20 particularly notable at the physical and pain dimensions. This finding also indirectly indicated the potential that dual-channel inhibition might alleviate chronic venous symptoms and enhance the quality of life in patients with long-term IVCF implantation.
The innovation of this study is evident in several key aspects. Firstly, it represents the first investigation into the efficacy and safety of dual-channel inhibition using rivaroxaban in conjunction with aspirin in patients with long-term IVCF implantation. Secondly, it transcends the therapeutic limitations associated with the use of a single anticoagulant. By targeting the dual pathways of “anticoagulation + antiplatelet” therapy, it not only addresses the recurrence of DVT but also effectively manages IVCFT, thereby offering a novel treatment option that balances both efficacy and safety in clinical practice. Thirdly, a thorough assessment of thrombotic event incidence, as well as VCSS and CIVIQ-20, was performed to comprehensively validate the advantages of the dual-channel inhibition regimen in enhancing short-term prognosis and quality of life for patients. The outcome indicators of this research align more closely with actual clinical needs.
Limitations
This study is not without its limitations. Firstly, a retrospective study is susceptible to selection bias and information bias. Patients with contraindications to anticoagulation were excluded from this study, which may introduce selection bias. These patients represent the typical population in whom IVCF is most commonly placed and long-term implantated. Therefore, the efficacy and safety findings of dual-channel inhibition therapy in the present study may not be directly generalized to patients with contraindications to anticoagulation, and further studies specifically targeting this high-risk population are warranted. Secondly, this study was retrospective in design, and no prospective sample size calculation or statistical power analysis was performed. The sample size was determined by the number of consecutive patients who met the inclusion criteria during the study period at the two centers. The relatively restricted sample size might have reduced the incidence of certain infrequent endpoints, such as PE, bleeding, and all-cause mortality. This also led to wide 95% CI for some endpoints (e.g., bleeding). Furthermore, due to the constraints imposed by the sample size, subgroup analyses of different types of IVCF were not performed. Thirdly, the follow-up period was confined to 12 months, which only captures mid-term efficacy and safety. Consequently, the long-term outcomes remain uncertain and necessitate further validation through subsequent long-term follow-up studies. Finally, multiple endpoints were compared without adjustment for multivariable analysis. Therefore, these endpoints analyses should be considered hypothesis-generating rather than confirmatory.
Conclusion
In conclusion, the dual-channel inhibition of rivaroxaban in conjunction with aspirin for patients with long-term IVCF implantation may significantly diminish the incidence of thrombotic events. This approach may also alleviate clinical symptom scores and enhance patients’ quality of life, while maintaining a controllable bleeding risk and ensuring good safety. Consequently, it offers a novel alternative for anticoagulation therapy among individuals with long-term IVCF implantation. This, in turn, contributes to the enhancement of patient prognosis and justifies its clinical promotion and application.
Footnotes
Acknowledgements
The authors are grateful to all the research participants and the staff that were involved in the study.
Ethical Considerations
This study was approved by the ethics committee of our medical institution (IRB Approval: 2023LLWL022) on January 22, 2026. Given the retrospective nature of this study, the requirement for informed consent was waived.
Author Contributions
Conceptualization: Yihao Wang, Lei Qi. Data curation: Hongzhi Sun, Lei Xiao. Resources, Supervision, Funding acquisition: Xianchen Huang. Formal analysis: Lei Qi, Hongzhi Sun. Investigation, Methodology: Yihao Wang, Lei Qi. Project administration: Yihao Wang, Lei Qi, Xianchen Huang. Writing-original draft: Yihao Wang, Lei Qi. Writing-review & editing: Yihao Wang, Lei Qi, Xianchen Huang.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Data Availability Statement
The authors declare that they had full access to all of the data in this study and the authors take complete responsibility for the integrity of the data and the accuracy of the data analysis. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions. Generative AI and AI-assisted technologies were NOT used in the preparation of this work.
Disclaimers
The authors’ statement that the views expressed in the submitted article are their own and not an official position of the institution or funder.
