Criteria to predict midterm outcome after stenting of chronic iliac vein obstructions (PROMISE trial).

ABSTRACT

BACKGROUND: Endovenous stent placement has become a first-line approach to prevent post-thrombotic syndrome in patients with chronic post-thrombotic obstruction (PTO) or nonthrombotic iliac vein lesions if conservative management fails. This study aims to identify factors associated with loss of patency to facilitate patient selection for endovenous stenting. METHODS: We retrospectively analyzed 108 consecutive patients after successful endovenous stenting for chronic vein obstruction performed at a single institution from January 2008 to July 2020. Using multivariable logistic regression, we explored potential predictive factors for loss of stent patency, including baseline demographics, post-thrombotic changes, and peak flow velocities measured in the common femoral vein (CFV), deep femoral vein, and femoral vein (FV) using duplex ultrasound examination. RESULTS: The mean follow-up duration was 41 ± 26 months, and participants had a mean age of 47.4 ± 15.4 years with 46.3% women. Ninety (83.3%) patients had PTO and 18 (16.7%) had nonthrombotic iliac vein lesions, predominantly due to May-Thurner syndrome. Loss of patency occurred in 20 (18.5%) patients, all treated for PTO. Comorbidities, side of intervention, and sex did not differ between patients with occluded and patent stents. Stent occlusion was more common with increasing number of stents implanted (P < .001) and with distal stent extension into and beyond the CFV (P < .001). Preinterventional predictive factors for stent occlusion were lower duplex ultrasound peak velocity in the CFV (odds ratio [OR] 7.52, 95% confidence interval [CI] 2.54-22.28; P < .001) and FV (OR 10.75, 95% CI 2.07-55.82; P < .005), and post-thrombotic changes in the deep femoral vein (OR 4.51, 95% CI 1.53-13.25; P = .006) and FV (OR 3.62 95% CI 1.11-11.84; P = .033). Peak velocities of ≤7 cm/s (interquartile range 0-20 cm/s) in the CVF and ≤8 cm/s (interquartile range 5-10 cm/s) in the FV were significantly associated with loss of patency. CONCLUSIONS: Insufficient venous inflow as assessed by low peak velocities in the CFV and FV as well as post-thrombotic findings represent reliable risk predictors for stent occlusions, warranting their inclusion into the decision-making process for invasive treatment of PTO.