Coagulation, fibrinolysis, and recanalization after acute deep venous thrombosis

Objective: Recanalization is common after acute deep venous thrombosis, but the factors that contribute to its variable extent are unknown. The purpose of this study was to examine the relationship between recanalization and plasma markers of coagulation and fibrinolysis. Methods: Subjects with an ultrasound-confirmed deep venous thrombosis had prothrombin fragment 1+2 (F 1+2), tissue plasminogen activator (t-PA) activity, plasminogen activator inhibitor (PAI-1) activity, and t-PA antigen levels determined before anticoagulation therapy. Ultrasound and plasma studies were repeated at 14 days, 1 month, and every 3 months for 1 year. Results: Among 71 enrolled subjects, F 1+2 levels normalized within 14 days. The mean t-PA activity was within the normal range at all follow-up intervals. However, the mean t-PA antigen (10.7 ± 10.5 to 13.6 ± 13.5 ng/mL; P = .04) and PAI-1 (9.0 ± 8.1 to 13.2 ± 17.3 U/mL; P = .05) levels increased between the time of presentation and day 14. The mean reduction in thrombus score among 44 patients who completed 9 months of follow-up was 60.9% (± 42.1%). Percent recanalization was directly associated with initial t-PA activity levels (R = .4; P = .006) and inversely related to F 1+2 (R. = -. 5; P = .004), t-PA antigen (R = -.5, P = .002), and PAI-1 (r = -. 5, P = .001) levels. However, only initial F 1+2 (P = .0009) and t-PA antigen (P = .004) levels were independent predictors of the degree of recanalization. Conclusion: Although the mechanisms by which the venous lumen is restored are still being elucidated, recanalization is inversely related to levels of activated coagulation (F 1+2) and fibrinolytic inhibition (t-PA antigen) at the time of presentation.