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 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 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.