The influence of May-Thurner syndrome on post-thrombotic syndrome in young women.

Background: The mechanism for post-thrombotic syndrome (PTS), the most important long-term sequelae of deep venous thrombosis, is not entirely known. It is probably caused by venous hypertension due to venous insufficiency and venous obstruction. Venous hypertension could also be a consequence of the May-Thurner syndrome (MTS), i.e. the obstruction of the common iliac vein. The aim of the present study was to explore if women with untreated MTS and a history of proximal DVT develop PTS more frequently. Patients and methods: A cohort of 68 female patients with a history of proximal left-sided DVT in the past were evaluated. According to Villalta score, they were segregated in two groups - with and without PTS (Villalta score ≥ 5 or < 5 points, respectively). For the diagnosis of MTS, magnetic resonance venography was performed. Results: Out of 68 patients, 25 developed PTS (36.8 %). Recurrent DVT, older age, pre-existent chronic venous insufficiency, and shorter compression stockings wearing time were statistically related to PTS. Deep and superficial valve incompetence was also significantly related to PTS, while incomplete thrombus removal showed only a trend towards PTS development. On the other hand, MTS per se turned out not to be linked to PTS. Conclusions: Our study suggests that women with MTS might not develop PTS more often, which puts aggressive treatment of MTS under question. More clinical trials are warranted to further examine this yet not fully explained field.