Double-Barrel Nitinol Stent Placement for Iliocaval Reconstruction: The Effect of Deployment Sequence and Direction

Clinical question

What is the influence of biomechanical forces on deployment outcomes of synchronous parallel stent deployment versus asynchronous or antiparallel stent deployment in cases of chronic, bilateral iliocaval occlusion?

Take away point

Synchronous parallel deployment is most likely to provide the desired stent configuration and shows superior clinical outcomes when performing double-barrel nitinol stent placement for treatment of chronic, bilateral iliocaval occlusion due to a balance in biomechanical forces.

Reference

Li N, Huber T, Campos L, Yamada K, Kaufman J, Farsad K, Bochnakova T. Double-Barrel Nitinol Stent Placement for Iliocaval Reconstruction: The Effect of Deployment Sequence and Direction on Final Configuration. J Vasc Interv Radiol. 2023 Sep;34(9):1511-1515.e1. doi: 10.1016/j.jvir.2023.05.018. Epub 2023 May 15. PMID: 37196821.

Click here for abstract.

Study design

In-vivo experimental with ex-vivo assessment utilizing swine models.

Funding Source

No reported funding.

Setting

Single academic center

Figure

Graphic illustration of the three (3) different double-barrel self-expanding nitinol venous stent deployment strategies across the iliocaval confluence (synchronous parallel, asynchronous parallel, and synchronous antiparallel) and their associated technical outcome tested in this study using a swine animal model.

Summary

    Despite the widespread use of double-barrel stents in venous interventions for chronic bilateral iliocaval occlusion, the differences in deployment outcomes between synchronous parallel stent deployment and asynchronous or parallel deployment, as well as the underlying biomechanical interactions of the stents, are not well understood.

    Using a live swine model, the diameters of the inferior vena cava (IVC) and common iliac veins were measured. Subsequently, 14 mm diameter double-barrel nitinol stents were deployed using three different techniques: (1) asynchronous parallel deployment from bilateral common femoral accesses, (2) antiparallel, synchronous deployment with the right common iliac stent deployed from the right internal jugular access and the left common iliac stent deployed from the left common femoral access, and (3) synchronous parallel deployment from bilateral common femoral accesses.

    Initial stent expansion was assessed under fluoroscopy, and all deployment strategies underwent simultaneous balloon angioplasty to 12 mm before being reassessed for their diameters. Following this, the peripheral IVC and bilateral common iliac veins were harvested and examined ex-vivo. The assessment was qualitative in nature, as statistical analysis was not performed due to the small sample size.

    Synchronous parallel stent deployment successfully achieved the desired double-barrel stent configuration due to an equilibrium among various biomechanical forces, including radial resistive force, chronic outward force, and crush resistance. However, both asynchronous parallel and antiparallel deployment strategies exhibited irreversible stent deployment issues, resulting in a crushed configuration due to unequal forces that compromised proper stent expansion.

    The authors recommend the use of intravascular ultrasound and multiprojection venography to confirm stent expansion and positioning. They also suggest that designing stents to mitigate force imbalances could be beneficial.

Commentary

    In this study, the authors investigated techniques and biomechanical forces impacting venous stent deployment. Although performed in a swine model, the principles are expected to apply to stent deployment in humans. This research has the potential to benefit patient care through technique optimization and product development. While study limitations may prevent direct correlation with human patient care, conducting future studies with larger sample sizes and controlled designs to allow for statistical analyses could be beneficial. In the interim, the principles demonstrated in this study can help achieve better stent placement and reduce potential complications.

Post author

Ryan R. Babayev, MD, MSc
Diagnostic Radiology Resident
Hartford Hospital
@RyanBabayevMD