Immediate post procedure anticoagulation with Factor Xa inhibitors of venous stents for non-thrombotic venous lesions does not increase stent patency.

Abstract Introduction Many clinicians anticoagulate patients after iliac vein stenting in order to prevent early or late stent thrombosis. It is currently unknown whether therapeutic anticoagulation has any effect on stent patency. The purpose of this investigation was to assess the role of short-term anticoagulation on iliac vein stent patency in patients with non-thrombotic iliac vein lesions (NIVL). Methods We performed a retrospective chart review of all iliac vein stents placed for NIVL at the Center for Vascular Medicine (CVM) from January 2018 to December 2019. We compared stent patency in two groups. The anticoagulation group (AC) was treated with Rivaroxaban or Apixaban post-operatively for a minimum of 90 days and compared to a group that received no post-operative anticoagulation (NAC). Stent patency was assessed with trans-abdominal ultrasonography at 3,6,12,18,24 and 30 months. At the discretion of the treating physician, patients who demonstrated thrombus layering on surveillance scanning were kept on Rivaroxaban or Apixaban until thrombus resolution was observed. Demographics, stent location, diameter and length were all assessed. Stent patency was analyzed utilizing life table analyses. Differences in stent patency were analyzed utilizing Graphpad Prism 8™ statistical software (GraphPad Software Inc, La Jolla, California) and the Log-Rank (Mantel-Cox) test. Results The number of patients and stents in each group are the following: AC (299/308), NAC (77/90) with an average age of 52.24±13.44 and 55.63±14.49 (p≤0.065), respectively. Women constituted 76% of all patients in the AC group and 72% in the NAC group. The average stent diameter and length for each group was AC (20±2mm./77±13mm) and NAC (19±2mm/82±9mm) respectively. Stents were placed in the right common iliac vein, bilaterally or left common iliac vein territory in 15%, 3% and 82% in the AC group and 18%, 2% and 80% in the NAC group respectively. The cumulative percent stent patency at 30 months was 98.7% and 94.6% for the NAC and AC groups respectively (p≤0.83). All stents placed were Wallstents. There were a total of 8 insertion site thromboses that did not affect stent patency: AC (n=5, 1.6%) versus NAC (n=3, 4.5%)(p=0.15). Nineteen patients demonstrated evidence of thrombus layering with six receiving extended anticoagulation. Conclusions Our data indicate that perioperative stent thrombosis in patients with NIVL lesions is uncommon. Anticoagulation for peri-operative stent thrombosis prophylaxis is not necessary. Anticoagulation should only be utilized in patients with insertion site thromboses and considered if thrombus layering is observed on surveillance scanning.