Outcomes and predictors of failure of iliac vein stenting after catheter-directed thrombolysis for acute iliofemoral thrombosis

Abstract

Objective: Iliac vein stenting is recommended to treat venous outflow obstruction after catheter-directed thrombolysis for acute iliofemoral deep venous thrombosis (DVT). Data on the outcome of proximal and distal stent extension are limited. Proximal stent extension to the vena cava may obstruct the contralateral iliac vein, whereas distal extension below the inguinal ligament contradicts common practice for arterial stents. The aim of this retrospective study was to assess outcomes and predictors of failure of iliac vein stents and contralateral iliac vein thrombosis, taking into consideration stent positioning.

Methods: Consecutive patients who underwent thrombolysis and stenting for DVT 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 (PTS; Villalta score ≥5), and contralateral DVT. Patients with chronic contralateral DVT or contralateral iliac vein stenting at baseline were excluded from the contralateral DVT outcome evaluation. Survival analysis and Cox regression models were used to determine outcomes.

Results: Of 142 patients lysed, 73 patients (12 bilateral DVTs; mean age, 45.8 ± 17.2 years; 46 female patients) were treated with various combinations of thrombolytic techniques and at least one self-expanding iliac stent (77 stented limbs). Thirty-day recurrence developed in nine (12.3%) patients. The 3-year primary patency and secondary patency rates were 75.2% and 82.2%, respectively. The single predictor for loss of primary patency was incomplete thrombolysis (≤50%; hazard ratio [HR], 7.41; P = .002). Overall, 3 of 12 (25%) stents extending below the inguinal ligament occluded at 1 month, 2 months, 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), stent extension below the inguinal ligament (HR, 6.68; P = .026), and male sex (HR, 6.02; P = .041). Of the 17 stents that extended into the contralateral common iliac vein and 58 stents that did not, 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.

Conclusions: Iliac stenting after thrombolysis for acute DVT guarantees high patency and low PTS rates, provided adequate thrombus resolution has been achieved before stent placement. Stent placement below the inguinal ligament does not affect the patency but may be associated with a higher PTS rate. Stenting proximal to the iliocaval confluence, although a precipitating factor, may not independently increase the likelihood of contralateral DVT.

Keywords: Catheter thrombolysis; Deep venous thrombosis; Iliac vein stenting; Post-thrombotic syndrome.