Iliac Vein Stenting Following Catheter Directed Thrombolysis for Acute Iliofemoral Thrombosis: Outcomes and Predictors of Failure

Abstract

Iliac vein stenting is recommended to treat venous outflow obstruction following catheter directed thrombolysis for acute iliofemoral thrombosis (IFDVT). Data on the outcome of proximal and distal stent extension is limited. Proximal stent extension to the vena cava may obstruct the contralateral iliac vein, while distal extension below the inguinal ligament contradicts common practice for arterial stents. The aim of the study was to assess outcomes and predictors of failure of iliac vein stents and contralateral iliac vein thrombosis taking into consideration stent positioning. Consecutive patients that underwent thrombolysis and stenting for IFDVT between May 2007 and September 2017 were identified from a prospectively maintained database. The intraoperative venograms were reviewed for proximal stent placement (covering >50%contralateral iliac vein orifice) and distal placement across the inguinal ligament. End points were ipsilateral DVT recurrence, post-thrombotic syndrome (Villalta score ≥5) and contralateral IFDVT. Patients with chronic contralateral DVT, or contralateral iliac vein stenting at baseline were excluded from the “contralateral IFDVT” outcome evaluation. Survival analysis and Cox regression models were used to determine outcomes. Out of 142 patients lysed, 73 patients (12 bilateral IFDVTs, mean age 45.8 ± 17.2 years, 46 females) were treated with various combinations of thrombolytic techniques and at least one self-expanding iliac stent (77 stented limbs). Thirty-day recurrence occurred in nine (12.3%) patients. The 3-year primary and secondary patencies were 75.2% and 85.2% respectively. The single predictor for loss of primary patency was incomplete thrombolysis (≤ 50%; hazard ratio [HR], 7.41; P = .002). Overall, 3/12 stents extending below the inguinal ligament failed at 1, 2 and 9 months respectively. The overall rate of PTS (Villalta score ≥5) in the stented cohort was 14.4% at 5 years. This was predicted by incomplete lysis (<50%) (HR, 7.09; P = .040), stenting below the inguinal ligament (HR, 6.68; P = .026) and male gender (HR = 6.02; P = .041). Out of 17 stents covering the contralateral common iliac vein and 58 stents not covering it, there were 1 (5.9%) and 5 (8.6%) contralateral DVTs (P = .588) at an average follow-up of 27.4 ± 33.7 and 22.2 ± 22.3 months (P = .552) respectively. Iliac stenting following thrombolysis for acute IFDVT guarantees high success rates provided that adequate thrombus resolution has been achieved prior to stent placement. Stent placement below the inguinal ligament does not affect the patency but may be associated to a higher PTS rate. Stenting proximal to the iliocaval confluence may not independently increase the likelihood of contralateral DVT.