Introduction

Post-thrombotic syndrome (PTS) is a common long-term complication of deep vein thrombosis (DVT) – and may be associated with venous obstruction and reflux.
The aim of the study is to assess the associations of thrombus location and extent, as well as abnormalities detected on long-term ultrasonographic follow-up, with the occurrence and severity of PTS.

Material and methods

The study included 100 patients who had experienced the first episode of proximal lower-extremity DVT at least 12 months earlier. The median interval between DVT and study assessment was 58 months. Post-thrombotic syndrome was assessed using the Villalta scale, whereas the severity of chronic venous disease was evaluated using the revised venous clinical severity score (rVCSS), venous disability score, and venous segmental disease score (VSDS). Duplex Doppler ultra-sonography was performed.

Results

Post-thrombotic syndrome was diagnosed in 74% of patients, including severe PTS in 6%. The mean rVCSS score was 8.15 ±3.49 in patients with PTS and 4.08 ±2.11 in those without PTS. An extensive persistent multilevel obstruction appeared to have the greatest clinical relevance. Reflux was associated primarily with more severe chronic venous disease according to the rVCSS, VSDS, and CEAP classification, whereas its association with PTS diagnosed using the Villalta scale was inconclusive.

Conclusions

Persistent multilevel obstructive lesions and pathological reflux are important factors associated with the severity of clinical symptoms in patients with a history of DVT. Further studies are required to define the risk factors for PTS. Despite the analysis of numerous variables, it is currently not possible to predict reliably which patients will develop PTS after an episode of proximal lower-extremity DVT.