A comparative study of altered hemodynamics in iliac vein compression syndrome

Ismael Z Assi; Sabrina R Lynch; Brian D Ricker; Siddhant V Ranjane; David M Williams; Thomas W Wakefield; Andrea T Obi; C Alberto Figueroa

doi:10.3389/fbioe.2024.1302063

A comparative study of altered hemodynamics in iliac vein compression syndrome

Front Bioeng Biotechnol. 2024 Jan 18:12:1302063. doi: 10.3389/fbioe.2024.1302063. eCollection 2024.

Authors

Ismael Z Assi¹, Sabrina R Lynch¹, Brian D Ricker², Siddhant V Ranjane¹, David M Williams³, Thomas W Wakefield⁴, Andrea T Obi⁴, C Alberto Figueroa^{1

4}

Affiliations

¹ Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States.
² School of Arts and Sciences, Johns Hopkins University, Baltimore, MD, United States.
³ Division of Vascular and Interventional Radiology, Department of Radiology, University of Michigan, Ann Arbor, MI, United States.
⁴ Section of Vascular Surgery, Department of Surgery, University of Michigan, Ann Arbor, MI, United States.

Abstract

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.

Keywords: Cockett syndrome; May-Thurner syndrome; computational fluid dynamics; iliac vein compression syndrome; patient-specific modeling; shear rate; thrombosis.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. SL was supported by the NSF Graduate Research Fellowship Program and the American Heart Association Fellowship (AHA 18PRE33960252). AO was supported by the Baiardi Family Foundation. CF was supported by the Edward B. Dietrich M.D. professorship in Biomedical Engineering and Vascular Surgery at the University of Michigan. IA, BR, SR, DW, TW received no external financial support for their role in this project.