Markers of coagulation, fibrinolysis and inflammation in relation to post-thrombotic syndrome.

BACKGROUND: Post-thrombotic syndrome (PTS) occurs in 20-50% of patients after a deep venous thrombosis (DVT). It is difficult to accurately predict which patients will develop PTS. Biomarkers could be a valuable tool for PTS risk assessment.

OBJECTIVES: To investigate whether increased levels of factor (F)VIII, C-reactive protein (CRP) or D-dimer, over time, are associated with the development of PTS in patients after an acute DVT.

METHODS: PTS status was assessed using the Villalta scale. Blood sampling was performed at three points during follow-up.

RESULTS: A cohort of 228 consecutive patients was included after an acute DVT. At T1 (12 months after index DVT), both levels of D-dimer (median 725 ng mL(-1) [interquartile range, IQR 400-1400[ vs. 378 ng mL(-1) [251-652] P=0.004) and CRP (median 3.9 mg L(-1) [IQR 1.6-8.5] vs. 2.4 mg L(-1) [1.0-4.3] P=0.018) were increased in patients with PTS, compared with patients without PTS. Factor (F)VIII was not associated with PTS. In the multivariate logistic regression analysis, varicosities (odds ratio [OR] 13.4 95% confidence interval [CI] 3.0-59.1 P=0.001), a previous ipsilateral DVT (OR 6.3 95% CI 1.5-26.9 P=0.012) and CRP>5 mg L(-1) on T1 (OR 8.0 95% CI 2.4-26.4 P=0.001) were significantly associated with PTS.

CONCLUSIONS: Besides previous ipsilateral DVT and varicosities, CRP>5 mg L(-1) at T1 was strongly and independently associated with PTS. Persistent inflammation rather than hypercoagulability might be the most important etiological factor in PTS, and may be a target for future therapy. The development of a risk score for PTS, including both clinical risk factors and biomarker levels, such as CRP, might be desirable.