Prevention of recurrent venous thrombosis and post-thrombotic syndrome.

Background: This retrospective registry study evaluated different managements on the development of post-thrombotic syndrome (PTS) and recurrent deep venous thrombosis (R-DVT). The effects of aspirin (100 mg/day), added to the "standard management" (SM) (IUA consensus), were observed in patients after a proximal DVT.

Methods: The study started after the anticoagulant period. Comparable groups used the mild-antithrombotic agent Pycnogenol® (200 mg/day), ticlopidine (250 mg/day) or sulodexide (500 ULS/day).

Results: The groups were comparable for sex and age distribution and clinical pictures. In the SM group, 222 patients completed the follow-up (72 months). With SM, the percentage of patients with R-DVT (requiring anticoagulants) was 17.2%; 19.8% of SM patients had a PTS. In the aspirin group (202 subjects), R-DVT was observed in 14.8% of patients; 17.32% had a PTS. The reduction in R-DVT and PTS with aspirin was significant (P<0.05) vs. the SM. There was no tolerability problem in subjects using Pycnogenol® (137 patients); they had a much lower incidence of R-DVT (5.8%) and PTS (6.5%) vs. SM and aspirin (P<0.05). Ticlopidine (121 patients) reduced the incidence of R-DVT (12.4%) and PTS (19.8% of patients) (P<0.05 vs. SM). With sulodexide the incidence of R-DVT was 6.7% (P<0.05 vs. SM); the incidence of PTS was 16.6% (P<0.05 vs. SM). The combined R-DVT+PT syndrome was observed in 14.9% of subjects using SM and in 12.9% of subjects using aspirin (P<0.05 vs. SM), in 3.6% of subjects managed with Pycnogenol® (<0.05% vs. aspirin and all other managements). The incidence was 10.74% with ticlopidine and 6.7% with sulodexide (both significantly lower than SM).

Conclusions: Interaction between PTS and R-DVT are complex; recurrences cause more PTSs, and a post-thrombotic limb is prone to R-DVT. Aspirin, for patients that can tolerate it, reduces the occurrence of PTS and R-DVT. In addition, ticlopidine and sulodexide are effective. Pycnogenol® is the most effective and safe for R-DVT and particularly PTS. Its full range of anti-thrombotic activity is now under evaluation.