Effect of stent treatment on hemodynamics in iliac vein compression syndrome with collateral vein

Effect of Balloon Dilatation and Stent Implantation in Iliac Vein Compression Syndrome

OBJECTIVE

 To investigate the efficacy of balloon dilatation combined with stent implantation in the treatment of iliac vein compression syndrome (IVCS).

METHODS

 This research was a retrospective study that enrolled 127 IVCS patients for clinical data. The patients were divided into percutaneous transluminal angioplasty (PTA) group (n = 63) and stent implantation group (n = 64). The PTA group was treated with iliac vein balloon dilatation, and the stent implantation group was treated with combined stent implantation based on the PTA group. In both the groups, the quality of life was assessed using Chronic Venous Insufficiency Quality of Life Questionnaire (CIVIQ); complications occurring during the perioperative period and at postoperative follow-up were recorded; the vascular patency rate was calculated, and patient's condition was evaluated using the Villalta scale.

RESULTS

 The stent implantation group exhibited lower postoperative CIVIQ scores than the PTA group, and the stent implantation group (4.60%) had lower complication rate than the PTA group (19.05%). At 2 years of follow-up, the stent implantation group (92.19%) had higher vascular patency rate than the PTA group (79.37%). Villalta scores were lower in the stent implantation group than in the PTA group at 6, 12, and 24 months postoperatively.

CONCLUSION

 Iliac vein balloon dilatation combined with stent implantation for the treatment of IVCS can improve vessel patency rates, alleviate patients' clinical symptoms, and enhance their quality of life.

Validation of the efficacy of the porous medium model in hemodynamic analysis of iliac vein compression syndrome

Iliac Vein Compression Syndrome (IVCS) is a common risk factor for deep vein thrombosis in the lower extremities. The objective of this study was to investigate whether employing a porous medium model to simulate the compressed region of an iliac vein could improve the reliability and accuracy of Computational Fluid Dynamics (CFD) analysis outcomes of IVCS. Pre-operative Computed Tomography (CT) scan images of patients with IVCS were utilized to reconstruct models illustrating both the compression and collateral circulation of the iliac vein. A porous medium model was employed to simulate the compressed region of the iliac vein. The agreements of times to peak between discrete phase particles in CFD analysis and contrast agent particles in Digital Subtraction Angiography (DSA) were compared. Furthermore, comparisons were made between the CFD analysis results that incorporated the porous media and those that did not. The results revealed that in the CFD analysis incorporating the porous media model, more than 80% of discrete phase particles reached the inferior vena cava via collateral circulation. Additionally, the concentration variation curve of discrete phase particles demonstrated a high concordance rate of 92.4% compared to that obtained in DSA. In comparison to CFD analysis conducted without the porous medium model, the incorporation of the porous medium model resulted in a substantial decrease in blood flow velocity by 87.5% within the compressed region, a significant increase in pressure gradient of 141 Pa between the inferior vena cava and left iliac vein, and a wider distribution of wall shear stress exceeding 2.0 Pa in collateral vessels rather than in the compressed region. The study suggests that the introduction of a porous medium model improves the hemodynamic analysis of patients with IVCS, resulting in a closer alignment with clinical observations. This provides a novel theoretical framework for the assessment and treatment of patients with IVCS.

Analysis of computed tomography venography for the diagnosis and endovascular treatment of iliac venous compression syndrome with venous leg ulcers: a retrospective study

Iliac vein compression syndrome (IVCS) is a clinical condition defined as obstruction of the iliac vein caused by chronic compression imposed by various causes. Currently, the clinical role of computed tomography venography (CTV) in the diagnosis of IVCS is unclear. Accurately diagnosing IVCS using CTV may enhance the understanding of the pathological anatomy of iliac veins, which may lead to better treatment outcomes, especially for recalcitrant venous leg ulcers (VLU). We aimed to investigate diagnostic criteria, contributing clinical factors, and stenting for IVCS with VLU in this study. CTV, digital subtraction angiography (DSV), and Doppler ultrasound (DUS) data were obtained from the medical and imaging records of 62 patients. Additionally, contributing factors and stenting for IVCS were analysed. Patients (100%) had clinical, aetiological, anatomic, or pathological C6 disease. CTV reduced the procedure time and contrast medium dose and provided more information than DSV. Risk factors for IVCS with VLU included female sex (P = 0.036) and advanced age (P = 0.014). The rate of ulcer healing was lower in the IVCS group without stent implantation (P = 0.020). Significant improvements were noted in venous clinical severity scores (P < 0.001) and chronic venous insufficiency questionnaire-20 scores (P < 0.001) after stenting for IVCS with C6 ulcers. CTV provides a more accurate diagnosis than DUS and DSV and allows detection of possible causes of IVCS. Female sex and advanced age were potential contributing factors for IVCS. Satisfactory outcomes were observed with stenting in the treatment of IVCS with C6 ulcers.

A comparative study of altered hemodynamics in iliac vein compression syndrome

Introduction: Iliac vein compression syndrome (IVCS) is present in over 20% of the population and is associated with left leg pain, swelling, and thrombosis. IVCS symptoms are thought to be induced by altered pelvic hemodynamics, however, there currently exists a knowledge gap on the hemodynamic differences between IVCS and healthy patients. To elucidate those differences, we carried out a patient-specific, computational modeling comparative study. Methods: Computed tomography and ultrasound velocity and area data were used to build and validate computational models for a cohort of IVCS (N = 4, Subject group) and control (N = 4, Control group) patients. Flow, cross-sectional area, and shear rate were compared between the right common iliac vein (RCIV) and left common iliac vein (LCIV) for each group and between the Subject and Control groups for the same vessel. Results: For the IVCS patients, LCIV mean shear rate was higher than RCIV mean shear rate (550 ± 103 s-1 vs. 113 ± 48 s-1, p = 0.0009). Furthermore, LCIV mean shear rate was higher in the Subject group than in the Control group (550 ± 103 s-1 vs. 75 ± 37 s-1, p = 0.0001). Lastly, the LCIV/RCIV shear rate ratio was 4.6 times greater in the Subject group than in the Control group (6.56 ± 0.9 vs. 1.43 ± 0.6, p = 0.00008). Discussion: Our analyses revealed that IVCS patients have elevated shear rates which may explain a higher thrombosis risk and suggest that their thrombus initiation process may share aspects of arterial thrombosis. We have identified hemodynamic metrics that revealed profound differences between IVCS patients and Controls, and between RCIV and LCIV in the IVCS patients. Based on these metrics, we propose that non-invasive measurement of shear rate may aid with stratification of patients with moderate compression in which treatment is highly variable. More investigation is needed to assess the prognostic value of shear rate and shear rate ratio as clinical metrics and to understand the mechanisms of thrombus formation in IVCS patients.