Summary
The post-thrombotic syndrome (PTS) occurs frequently after deep venous thrombosis
(DVT) despite appropriate anticoagulant therapy. A close relationship between inflammation
and thrombosis exists. While the inflammatory process at the time of DVT appears to
improve thrombus resolution, it may promote destruction of venous valves, valvular
reflux and subsequent development of PTS. We prospectively evaluated the association
between levels of four cytokines (IL-6, IL-8, IL-10 and MCP-1), two adhesion molecules
(ICAM-1 and VCAM-1) and the development of PTS in a well-defined cohort of patients
with DVT. The study population consisted of 387 patients with objectively diagnosed
symptomatic DVT who were followed for two years to determine the incidence of PTS.
At the end of follow-up, plasma samples frozen at the four-month visit in 307 study
patients were thawed and analyzed for the above inflammatory markers using the Luminex
beads technology. Mean levels of IL-6 were significantly higher in patients with PTS
compared to patients without PTS (7.35 pg/ml ± 14.26 [SD] vs. 4.60 pg/ml ± 4.90;p=0.03).
Logistic regression analyses showed significant associations between PTS and levels
above vs. below the median of IL-6 [odds ratio (OR) 1.66; 95% confidence interval
(CI) 1.05, 2.62 (p=0.03)] and ICAM-1 [OR 1.63; 95% CI 1.03, 2.58 (p=0.04)]. None of
the other markers showed any association with PTS. Our study suggests the presence
of significant associations between markers of inflammation such as IL-6 and ICAM-1
and the development of PTS. Further work is needed to evaluate this relationship and
to analyse other candidate markers that could be implicated etiologically in the association
between DVT and PTS. If confirmed, this could lead to identification of new therapeutic
targets for preventing PTS after DVT.
Keywords
Post-thrombotic syndrome - deep venous thrombosis - inflammation - interleukins -
adhesion molecules