Prognostic factors influencing venous patency after thrombectomy in patients with May-Thurner syndrome

Abstract

Purpose: To evaluate the prognostic significance of venographic findings and procedural factors for long-term venous patency after thrombectomy in patients with May-Thurner syndrome (MTS)-associated deep vein thrombosis (DVT).

Materials and methods: This retrospective cohort study included 75 patients with iliofemoral DVT secondary to MTS, who underwent thrombectomy between January 2011 and April 2023. Key venographic findings-venous stenosis (≥50%), venous spur, and persistent collaterals-along with stent placement and diameter were analyzed. The primary outcome was 24-month venous patency, assessed using univariate tests, Kaplan-Meier survival analysis, and multivariate Cox proportional hazards modeling.

Results: At 24 months, 58 patients (77.3%) maintained venous patency, whereas 17 (22.7%) experienced reocclusion. Univariate and Kaplan-Meier analyses showed that stenosis ≥50%, venous spur, persistent collaterals, and absence of stent placement were significantly associated with reduced patency (all p < 0.05). However, in the multivariate Cox model, only venous stenosis ≥50% remained a statistically significant independent predictor of reocclusion (hazard ratio [HR]=5.04; 95% Confidence Interval: 1.28-19.82; p = 0.021). Stent placement (HR = 1.78; p = 0.337) and diameter (p = 0.349) were not independently associated with patency.

Conclusion: Residual venous stenosis ≥50% following thrombectomy is an independent predictor of reduced long-term patency in patients with MTS. While stent placement was associated with better outcomes in the univariate analysis, it did not independently predict patency after adjustment, likely due to treatment-related confounding factors. Effective anatomical resolution of stenosis may be more critical than stent deployment. Prospective studies are warranted to clarify the prognostic impact of venographic findings and interventional strategies.

Fig 1. Case accrual process.

Fig 2. Endovascular treatment of May-Thurner syndrome-associated iliofemoral deep vein thrombosis in a 76-year-old woman.

A. Contrast-enhanced computed tomography venography showing compression of the left common iliac vein (LCIV) by the overlying right common iliac artery and L4 vertebral body (arrow), consistent with May-Thurner syndrome. B. Conventional venography reveals a prominent venous spur and > 50% luminal narrowing at the LCIV (arrowhead), along with collateral venous flow (asterisk). C. Post-stenting venogram after the deployment of a 14-mm self-expandable stent demonstrating complete resolution of venous stenosis, spur formation, and collateral flow.

Fig 3. Kaplan–Meier curve showing 24-month cumulative primary patency stratified by venographic and procedural factors.

Each graph shows the cumulative primary patency rates among patients with and without specific risk factors. Differences in the survival distribution were assessed using log-rank tests. A. Venous stenosis. Patients with stenosis ≥50% showed significantly lower patency compared to those with <50% stenosis (p < 0.001). B. Venous spur. Presence of luminal irregularity (spur) was associated with inferior patency outcomes (p < 0.001). C. Persistent Collateral Veins. Patients without collateral flow demonstrated significantly higher patency rates than those with persistent collateral flow (p = 0.001). D. Stent placement. Patients who underwent stent placement had a higher long-term patency than those who did not (p = 0.019). E. Stent diameter. Among patients with stent placement, no significant difference in patency was observed between stents ≤12 mm and >12 mm in diameter (p = 0.332).