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Poster Networking

Venous Thromboembolism

PB0923 - Biomarkers for prediction of thrombus resolution after acute deep vein thrombosis in the lower extremities

Monday, June 24, 2024
13:45 – 14:45 ICT
Room: Exhibition Hall
Background: Elevated factor VIII (FVIII) and D-dimer levels obtained in follow-up have been associated with post-thrombotic symptoms.

Aims: To determine if measurement of coagulation factors at the time of acute DVT was predictive of subsequent thrombus resolution.

Methods: Eligible adults were recruited to undergo additional laboratory testing {D-dimer, high-sensitivity C-reactive protein (CRP), FVIII activity, Plasminogen Activator Inhibitor 1 activity (PAI-1)} within 72 hours of confirmed acute proximal lower extremity DVT. Exclusion criteria: anticoagulation at the time of the DVT, known DVT diagnosed within the last 3 months, planned systemic or catheter-directed thrombolysis, cast immobilization of the extremity, or contraindication for a standard course of therapeutic anticoagulation. Subjects underwent follow-up ultrasound at 3 months and thrombus resolution was graded independently by 2 vascular radiologists.

Results: A total of 96 lower extremity vein segments with acute DVT (n=12 patients) were analyzed with initial laboratory assessment and follow-up ultrasound. Median D-dimer was 3504ng/mL FEU (IQR 1421-4879), CRP was 4mg/L (IQR 1-14), PAI-1 was 16ng/mL (IQR 8-24), and FVIII was 201% (IQR 176-309). The median initial thrombosis score (1 pt for non-occlusive, 2 pts for occlusive thrombus per vein segment) was 7.5 (IQR 5-12), mean 8 (SD 4.3). Only 4 of 12 patients had complete resolution by ultrasound at follow-up. In univariate analyses per vein segment, higher FVIII (R2=0.22, p=0.003) activity levels at baseline (Figures) and lower BMI were associated with residual DVT at 3 months. In multivariable linear regression, age (p=0.006), BMI (p < 0.001), FVIII (p=0.002), and PAI-1 (p=0.009) were all predictive of thrombus resolution (R2=0.47, p< 0.001).

Conclusion(s): In this pilot study we found that FVIII and PAI-1 measured at the time of acute DVT could aid in the prediction of thrombus resolution at 3 months. A larger sample size is needed to more fully elucidate these findings and determine how they relate to symptomatic post-thrombotic syndrome.