Laboratory assays and duplex scanning outcomes after symptomatic deep vein thrombosis: preliminary results

The purpose of this article was to assess a number of hematologic and fibrinolytic assays at the time of diagnosis of deep vein thrombosis (DVT) and at several intervals over a period of 6 months afterward and to correlate these results with the results of serial duplex scanning.

Thirty-five patients (average age 61, range 18 to 82) with acute symptomatic DVT confirmed by duplex scanning were included. On diagnosis, blood was drawn, and plasma levels of tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor (PAI), D-dimer (DD), and tissue factor pathway inhibitor (TFPI) were determined. Duplex scanning and all laboratory assays were repeated 1 week, 1 month, 3 months, and 6 months thereafter.

The rate of DVT complete resolution 6 months after diagnosis was 57%. Whereas plasma levels of PAI were similar throughout the 6-month follow-up period, t-PA increased significantly 1 week after diagnosis and decreased thereafter. Both DD and TFPI levels decreased significantly after diagnosis compared with presentation values. Comparing these assay levels between patients with complete resolution versus partial or no resolution, PAI levels were significantly higher during the first week in patients with poor outcome. Plasma levels of t-PA were higher in cases with good outcome, and DD levels were higher in patients with poor outcome. TFPI levels were similar in both outcome groups.

Patients with complete DVT resolution on duplex scanning at 6 months had significantly lower levels of PAI on presentation and after 1 week than did those with incomplete lysis. Although differences were not significant, t-PA levels were higher and DD lower in patients with good outcome. Our results suggest that certain plasma fibrinolytic assays might correlate with the outcome of DVT, as assessed by duplex ultrasonography.