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March 2, 2022
Study Evaluates Incidence of and Risk Factors for IVC Thrombosis in Patients With IVC Filters
March 2, 2022—In a retrospective study of patients with an indwelling inferior vena cava (IVC) filter, Xiao and colleagues found a 2% incidence of IVC thrombosis, which was more commonly seen in male patients, those with neurologic disease, and those who received a Denali IVC filter (BD Interventional). Results were published in Radiology.
Key Findings
- IVC filter–related IVC thrombosis occurred in 2% of patients.
- Male sex, central neurologic disease, and implantation time > 6 months were significantly associated with the development of IVC thrombosis.
- Seventeen IVC filter types were encountered; the Denali IVC filter was significantly associated with IVC thrombosis.
Investigators aimed to evaluate the incidence of IVC thrombosis in patients with an IVC filter and identify risk factors associated with the development of IVC thrombosis. Patients were included if they had an IVC filter and underwent either catheter venography at the time of retrieval or CT of the abdomen/pelvis between January 1, 2009 and January 1, 2019. Patients were routinely monitored in a dedicated IVC filter clinic, where assessments for imaging and retrieval were performed. Those who did not undergo follow-up imaging after filter placement were excluded.
IVC thrombosis was defined as complete caval thrombosis through the indwelling filter. History of prior venous thromboembolism, neurologic disease, known genetic hypercoagulability, contraindications to anticoagulation, anticoagulation therapy at the time of follow-up, IVC filter type, and implantation time were assessed for association with IVC thrombosis.
Sensitivity analysis and logistic regression were performed at 6, 12, and 24 months after implantation to assess for a temporal association with IVC thrombosis. Univariable analysis was performed to evaluate the association between IVC thrombosis and potential risk factors (Bonferoni correction applied; P < .0026 was significant). Multivariable logistic regression was used to assess for independent predictors of IVC thrombosis among the examined covariates/risk factors.
Of 2,077 patients, 1,582 met inclusion criteria; of these, 38 (2%) patients developed IVC filter–related IVC thrombosis. Univariable analysis showed that male sex (odds ratio [OR], 5.0; 95% CI, 2.1-12.1; P < .001), central neurologic disease (OR, 4.4; 95% CI, 2.3-8.5; P < .001), and implantation time > 6 months (OR, 3.8; 95% CI, 2.0-7.2; P < .001) were significant risk factors for development of IVC thrombosis, and these remained significant with multivariate adjustment.
Mean filter implantation time was 17 months, and mean time from IVC filter placement to IVC thrombosis diagnosis was 32.9 months. A total of 17 filter types were included in this analysis, and the Denali filter was significantly associated with IVC thrombosis (OR, 8.9; 95% CI, 2.5-31.8; P = .001).
The investigators noted that most patients underwent prompt retrieval of the IVC filters, which may have skewed the results toward lower overall dwell times and potentially underestimated the risk of IVC filter–related IVC thrombosis. However, they concluded that the data accurately reflect clinical practice and provide guidance in risk assessment for IVC filter–related IVC thrombosis.
ENDOVASCULAR TODAY ASKS…
Senior investigator Kush Desai, MD, with Northwestern University in Chicago, Illinois, was asked to provide some insight into the study’s results:
Of the risk factors found to be associated with a higher incidence of IVC thrombosis, which are notable?
Some of the findings of our study are confirmatory of prior investigations, whereas others may prompt future studies. For example, male sex as a risk factor for IVC filter–related IVC thrombosis does not come as a surprise, as there have been numerous studies that have identified that males are at a higher risk of first-time and recurrent venous thrombosis relative to females. Neurologic disease is less well described as a risk factor for venous thrombosis. Our findings, paired with findings from other small studies, suggest that this is worthy of further investigation.
From a practical standpoint, how might these findings inform decision-making for patients in the groups with higher observed association at the time of implantation?
It may be possible to reduce the risk of IVC filter–related IVC thrombosis through the application of rigorous preplacement screening of patients for comorbidities that increase their risk. On a more fundamental level, a thorough examination of the indications for filter placement is necessary. Interventionalists consulted for filter placement should consider whether a filter is truly indicated, and if the indication is not clear or is relative, a collaborative discussion with the requesting clinician is important prior to proceeding.
Management of patients with IVC filters involves interventional and noninterventional physicians. What are some ways to optimize the longitudinal care of these patients?
The findings of our study have shown a similar rate of IVC filter–related IVC thrombosis as prior studies, around 2%. Although this rate is not terribly high, the sheer number of patients with indwelling filters, along with patients who receive new filters, suggests that this problem will be ongoing. In 2010 and 2014, the FDA delivered safety communications suggesting that implanting physicians are responsible for the management of patients with retrievable IVC filters and that retrieval should be considered when the device is no longer indicated. In keeping with that recommendation, the issue of prolonged implantation as a risk factor may be addressed through diligent follow-up by interventionalists with the primary care physicians, as well as patients themselves, to ensure prompt retrieval. Consistent communication between comanaging physicians and the patient is key to improving outcomes.
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