Lower Extremity Venous Stent Placement: A Large Retrospective Single-Center Analysis.

PURPOSE: To study short-term and long-term outcomes of lower extremity venous stents placed at a single center and to characterize changes in vein diameter achieved by stent placement. MATERIALS AND METHODS: A database of all patients who received lower extremity venous stents between 1996 and 2018 revealed 1,094 stents were placed in 406 patients (172 men, 234 women; median age, 49 y) in 513 limbs, including patients with iliocaval stents (9.4% acute thrombosis, 65.3% chronic thrombosis, 25.3% nonthrombotic lesions). Primary, primary assisted, and secondary patency rates were assessed for lower extremity venous stents at 1, 3, and 5 years using Kaplan-Meier analyses and summary statistics. Subset analyses and Cox regression were performed to identify risk factors for patency loss. Vein diameters and Villalta scores before and up to 12 months after stent placement were compared. Complication and mortality rates were calculated. RESULTS: Primary, primary assisted, and secondary patency rates at 5 years were 57.3%, 77.2%, and 80.9% by Kaplan-Meier methods and 78.6%, 90.3%, and 92.8% by summary statistics. Median follow-up was 199 days (interquartile range, 35.2-712.0 d). Patency rates for the subset of patients (n = 46) with ≥ 5 years of follow-up (mean ± SD 9.1 y ± 3.4) were nearly identical to cohort patency rates at 5 years. Patients with inferior vena cava stent placement (hazard ratio 2.11, P < .0001) or acute thrombosis (hazard ratio 3.65, P < .0001) during the index procedure had significantly increased risk of losing primary patency status. Vein diameters were significantly greater after stent placement. There were no instances of stent fracture, migration, or structural deformities. In patients with chronic deep vein thrombosis, Villalta scores significantly decreased after stent placement (from 15.7 to 7.4, P < .0001). Perioperative mortality was < 1%, and major perioperative complication rate was 3.7%. CONCLUSIONS: Cavo-ilio-femoral stent placement for venous occlusive disease achieves improvement of vein disease severity scores, increase in treated vein diameters, and satisfactory long-term patency rates.

Toward Data-Driven Learning Healthcare Systems in Interventional Radiology: Implementation to Evaluate Venous Stent Patency.

We developed a code and data-driven system (learning healthcare system) for gleaning actionable clinical insight from interventional radiology (IR) data. To this end, we constructed a workflow for the collection, processing and analysis of electronic health record (EHR), imaging, and cancer registry data for a cohort of interventional radiology patients seen in the IR Clinic at our institution over a more than 20-year period. As part of this pipeline, we created a database in REDCap (VITAL) to store raw data, as collected by a team of clinical investigators and the Data Coordinating Center at our university. We developed a single, universal pre-processing codebank for our VITAL data in R; in addition, we also wrote widely extendable and easily modifiable analysis code in R that presents results from summary statistics, statistical tests, visualizations, Kaplan-Meier analyses, and Cox proportional hazard modeling, among other analysis techniques. We present our findings for a test case of supra versus infra-inguinal ligament stenting. The developed pre-processing and analysis pipelines were memory and speed-efficient, with both pipelines running in less than 2 min. Three different supra-inguinal ligament veins had a statistically significant improvement in vein diameters post-stenting versus pre-stenting, while no infra-inguinal ligament veins had a statistically significant improvement (due either to an insufficient sample size or a non-significant p value). However, infra-inguinal ligament stenting was not associated with worse restenosis or patency outcomes in either a univariate (summary-statistics and Kaplan-Meier based) or multivariate (Cox proportional hazard model based) analysis.