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. 2025 May 5;25(1):151.
doi: 10.1186/s12880-025-01695-0.

Nomogram-based prediction of the prognosis in patients with free floating venous thrombus after closed traumatic fracture

Yao Wei  1 , Changxu Guo  2 , Xiaoyu Chen  2 , Yu Yuan  2
Affiliations

Nomogram-based prediction of the prognosis in patients with free floating venous thrombus after closed traumatic fracture

Yao Wei et al. BMC Med Imaging. .

Abstract

Background: Free-floating venous thrombosis (FFVT), a distinct subtype of deep vein thrombosis (DVT), is associated with pulmonary thromboembolism (PTE) and carries a high mortality risk.

Objective: This study aimed to develop a nomogram to predict the prognosis of FFVT in patients with closed traumatic fractures.

Materials and methods: A retrospective analysis of clinical and ultrasound data from 326 patients with FFVT post-closed traumatic fractures was conducted. Patients were divided into training (n = 240, January 2019-June 2023) and validation (n = 86, June 2023-June 2024) sets. Prognostic risk factors were identified using LASSO and multivariable logistic regression. A nomogram was constructed using R Studio, and its predictive accuracy was validated via calibration curves, receiver operating characteristic (ROC) analysis, and external validation.

Results: Independent risk factors for FFVT progression to closed thrombus included D-dimer levels, FFVT location, collateral blood flow volume around the thrombus, and thrombus margins (P < 0.05). The model demonstrated high discriminative ability, with a C-index of 0.945. ROC analysis revealed areas under the curve (AUC) of 0.949 (training set) and 0.924 (validation set). Calibration curves confirmed strong agreement between predicted and observed outcomes.

Conclusion: The nomogram provides an accurate prognostic tool for FFVT in patients with closed traumatic fractures, aiding clinical decision-making to improve patient outcomes.

Clinical trial number: Not applicable.

Keywords: Free floating venous thrombosis; Nomogram; Prediction model; Prognosis; Risk factors.

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Conflict of interest statement

Declarations. Ethics approval and consent to participate: The study was conducted in accordance with the principles of the Declaration of Helsinki and Good Clinical Practice guidelines. The study was approved by the Medical Ethics Committee of Tianjin Hospital (2024MER204). Written informed consent was waived due to the nature of retrospective study. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Representative ultrasonic imaging. A) Color Doppler imaging revealed Free-Floating Venous Thrombus (FFVT) in the right femoral vein, presenting with blood high-flow around the FFVT in iliac-femoral vein. B) A male patient developed a FFVT in the right popliteal vein after a traumatic injury by a two-dimensional image and a color Doppler image. On the 28th day after discharge, a follow-up ultrasound showed that the thrombus had dissolved and disappeared
Fig. 2
Fig. 2
Variable selection by the LASSO binary logistic regression model. A) LASSO coefficient profile plot was produced for filtering variables; B) The optimal penalty coefficient lambda (λ) was generated in LASSO through tenfold cross-validation. The partial likelihood deviation (binomial deviation) curve versus log (λ) was plotted. Dotted vertical lines were drawn based on one standard error criterion
Fig. 3
Fig. 3
Predictive nomogram for the prognosis of patients with FFVT after closed traumatic fracture
Fig. 4
Fig. 4
Receiver operating characteristic (ROC) curves for the assessment of accuracy of nomogram prediction model. A) The training set, B) The validation set
Fig. 5
Fig. 5
The calibration curves for FFVT prognosis risk nomogram in patients with closed traumatic fractures of A) the training set and B) the validation set. The x-axis represented the nomogram-predicted probability, and y-axis represented the actual probability of a free-floating thrombus failing to resolve and progressing to a closed thrombus
See this image and copyright information in PMC

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