Post thrombotic syndrome after thrombotic venous thoracic outlet syndrome

Thrombotic venous thoracic outlet syndrome (T-vTOS) including Paget-Schrotter syndrom is a rare form of upper extremity deep vein thrombosis (UEDVT) that mainly affects young, active individuals. Its optimal management remains debated and medium-term outcomes are poorly documented.

Consecutive patients from the vascular medicine department of a university hospital with T-vTOS between 2014 and 2024 were included in a retrospective study. Patients were stratified according to the presence of post-thrombotic syndrome with the modified Villalta score at last follow-up (<5 vs ≥5). Clinical characteristics, therapeutic strategies and outcomes were systematically assessed through a standardized consultation performed by the same physician. Univariable and multivariable logistic regression analyses, using Firth's penalized-likelihood method to account for the limited number of events, were performed to identify factors associated with post-thrombotic syndrome.

Fifty patients were included: 28 with a Villalta score <5 and 22 with a Villalta score ≥5 at last follow-up. Patients with Villalta <5 achieved higher rates of complete subclavian vein recanalization at follow-up (63% vs 32%, p=0.045) and were less likely to have persistent subclavian vein occlusion (26% vs 59%, p=0.023). Villalta ≥ 5 patients more often required prolonged anticoagulation (73% vs 29%, p=0.004) and more frequently underwent acute-phase endovascular treatment (36% vs 4%, p=0.007). In multivariable analysis endovascular treatment alone without thoracic outlet surgery was associated with PTS (OR 10.6, 95% CI 1.15; 98.09) (p=0.037), whereas there was no association between PTS and patients who had undergone both endovascular treatment and TOS surgery: OR 1.3 (95% CI 0.26; 6.87) (p=0.736).

This study highlights the central role of venous patency in the clinical course of T-vTOS, with persistent subclavian vein occlusion associated with post-thrombotic syndrome. The association observed between acute-phase endovascular treatment alone and post-thrombotic syndrome does not support a clear benefit of this strategy. However, endovascular therapy in conjunction with surgical decompression of the thoracic outlet may reduce the risk of post-thrombotic syndrome.