Treatment of the Postthrombotic Syndrome With the Oblique Stent - TOPOS Study

Inclusion Criteria: 1. Male or female adults aged ≥18 years 2. Post-thrombotic syndrome (Villalta score \>4 points) due to iliac vein thrombosis with or without femoral deep vein thrombosis 3. Evidence of venous stenosis in common iliac vein \>50% confirmed by venography (CT or MRI) or intravascular ultrasound (IVUS) 4. Use of sinus-Obliquus stent for unilateral common iliac vein stenosis 5. If stent extension is required either sinus-XL Flex or sinus-Venous stents must have been used for stenoses \>50% confirmed by venography (CT or MRI) or IVUS in external iliac and common femoral veins Exclusion Criteria: 1. Pregnancy, breast-feeding or birth-giving during the last 30 days 2. Life expectancy \<6 months 3. Iliofemoral DVT less than 3 months ago 4. Permanently immobile patient (wheelchair user or bed-ridden patient) 5. Allergy to Nitinol 6. Patient's target vessel(s) has/have been stented before 7. Legal incapacity and/or other circumstances rendering the patient unable to understand the nature, scope and possible impact of the study 8. Patients in custody by juridical or official order