Little is known about pathogenetic mechanisms of superficial venous thrombosis (SVT). We aimed to investigate the systemic inflammatory response in the acute phase of SVT, the time course of inflammatory markers and involvement of inflammation in resolution of thrombus in SVT.

The circulatory inflammatory parameters high-sensitivity C-reactive protein (hsCRP), tumor necrosis factor α (TNF-α), interleukins 6, 8 and 10 (IL-6, IL-8, IL-10), and markers of fibrinolytic activity tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1) and fibrinogen were determined in 68 patients with acute SVT of lower limbs, who were allocated to two groups, dalteparin 5000 IU once daily or 10 000 IU once daily. Recanalization of occluded veins was monitored by ultrasonography at regular intervals. Blood was drawn in the acute phase and after 12 weeks.

In the acute phase a majority of the measured inflammatory markers were increased, while after 12 weeks most of them significantly dropped: hsCRP: 13.6 ±11.9 vs. 7.4 ±4.4, < 0.001; IL-6: 3.8 ±3.1 vs. 2.6 ±1.9, = 0.007. Significant changes in endogenic fibrinolytic parameters were also observed: t-PA activity decreased (0.81 ±0.35 vs. 0.68 ±0.34, = 0.003), while PAI-1 levels increased (5.6 ±5.1 vs. 8.8 ±8.5, < 0.001). Levels of inflammatory markers at inclusion and after 12 weeks were related to less effective thrombus resolution: CRP: = 0.386, = 0.001; IL-6: = 0.384; TNF-α: = 0.255, = 0.037.

In the acute phase of SVT, most of the circulating inflammatory markers were increased and most of their levels decreased after 12 weeks. Levels of inflammatory markers were negatively correlated with the recanalization rate.