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

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.