Plasma D-Dimer Changes and Clinical Value in Acute Lower Extremity Deep Venous Thrombosis Treated with Catheter-Directed Thrombolysis.

Objective: This study sought to investigate the changes in plasma D-dimer levels during catheter-directed thrombolysis (CDT) in patients with acute lower extremity deep venous thrombosis (DVT), analyze imaging results, and assess their clinical implications.

Methods: We retrospectively analyzed 62 patients diagnosed with acute lower extremity DVT who underwent CDT between March 2019 and December 2022. Plasma D-dimer levels were measured before CDT, at regular intervals after CDT, and at the end of CDT. Lower limb venography was performed every two days during CDT to assess the thrombus clearance rate and level of thrombus dissolution. Statistical analysis was conducted to observe the D-dimer concentration changes and analyze the correlation between D-dimer concentration and thrombus clearance rate. Additionally, a receiver operating characteristic (ROC) curve was constructed to determine the diagnostic performance of D-dimer in assessing the efficacy of thrombolysis, including the calculation of the area under the curve (AUC), sensitivity, specificity, and optimal cut-off value.

Results: During CDT for acute lower extremity DVT, plasma D-dimer levels rapidly increased, peaking on CDT day 1, and then gradually decreased, followed by a rapid decline but remained slightly elevated compared to normal levels. There was a positive correlation between D-dimer levels and thrombolysis efficacy (r = 0.809, P = 0.00). The linear regression equation for this correlation was Y = 0.161 + 0.028X. The AUC of D-dimer was 0.95, with a cut-off value of 9.935 mg/L (sensitivity 93.2% and specificity 95.4%).

Conclusion: Plasma D-dimer concentration can serve as an indicator for evaluating the efficacy of thrombolysis during CDT in acute lower extremity DVT.