Braided or laser-cut self-expanding nitinol stents for the common femoral vein in patients with post-thrombotic syndrome.

BACKGROUND: Chronic obstruction of the common femoral vein in patients with post-thrombotic syndrome after iliofemoral or iliocaval deep vein thrombosis has remained a challenge for endovascular treatment. The patency rates and clinical outcomes of laser-cut and braided nitinol stents extending to the common femoral vein have not yet been studied. METHODS: From the Swiss and Arnsberg Venous Stent Registries, we included 150 patients with post-thrombotic syndrome (mean age, 44 ± 16 years; 48% women) with laser-cut (n = 101) or braided nitinol (n = 49) stents placed into the common femoral vein across the inguinal ligament. Routine follow-up included duplex ultrasound examinations and assessment of clinical scores. The primary study outcomes were the primary and secondary patency rates at 12 months. RESULTS: Overall, the mean number of implanted stents was 2.6 ± 1.7. The proximal stent landing zone was the inferior vena cava in 32 patients (21%), the iliac vein in 106 patients (76%), and the common femoral vein in 5 patients (3%). The primary patency rate was 67.3% (95% confidence interval [CI], 58.0%-76.6%) in the laser-cut group and 86.7% (95% CI, 75.3%-98.1%) in the braided stent group (log-rank, P = .016). The corresponding secondary patency rates were 93.9% (95% CI, 89.2%-98.6%) and 100% (log-rank, P = .10). The median improvement in the Villalta score from baseline to the latest follow-up was 4 points (interquartile range, 2-6 points), without significant differences between the two groups. Symptomatic common femoral vein stent fractures were observed in four patients (4%) with laser-cut stents but in no patient with braided stents. CONCLUSIONS: The use of braided nitinol stents for common femoral vein obstruction appeared to be associated with favorable primary patency rates at 12 months compared with laser-cut nitinol stents. Further studies are needed to confirm that braided nitinol stents remain patent and might be less prone to fractures in the long term.

Self-Expandable Nitinol Stents for the Treatment of Nonmalignant Deep Venous Obstruction.

BACKGROUND: Angioplasty with stent placement is a therapeutic option for patients with acute thrombotic, postthrombotic, and nonthrombotic obstruction of the iliofemoral veins or inferior vena cava. Previous studies of steel-alloy stents described variable patency rate across indications. METHODS: The prospective Swiss Venous Stent Registry includes patients treated with self-expandable nitinol stents for deep venous obstruction. Routine follow-up visits include serial duplex ultrasound for stent patency assessment. The primary outcome was primary stent patency. The secondary outcome was venous thromboembolisms. We studied the rate of stent occlusion and potentially contributing factors. RESULTS: We included 379 patients: 160 with acute thrombotic, 193 with postthrombotic, and 26 with nonthrombotic deep vein obstruction. The mean age was 46±18 years; 55% were women. The cumulative 3-year primary patency rate was 80.5% (95% CI, 73.0%-88.0%) for acute thrombotic, 59.2% (95% CI, 50.4%-68.0%) for postthrombotic, and 100% for nonthrombotic obstruction (log-rank, P<0.0001). Annualized rates of stent occlusion or venous thromboembolism were 7.8 (acute thrombotic), 15.0 (postthrombotic), and 0 (nonthrombotic) events/100 patient-years. In a multivariable Cox regression model, postthrombotic femoral veins at baseline (hazard ratio, 2.64 [95% CI, 1.53-4.56]) and the number of stents (hazard ratio, 1.22 [95% CI, 1.06-1.40]) were associated with stent occlusion after conditioning for age, sex, and clinically relevant factors. CONCLUSIONS: The rate of stent occlusion (patency loss) and venous thromboembolism varies substantially across indications, also with dedicated venous nitinol stents. Patients with postthrombotic femoral veins and those who received multiple stents were characterized by the highest risk. Registration: URL: https://clinicaltrials.gov. Unique identifier: NCT02433054.