Identifying causes of complications in aortic stent graft surgery

Aortic dissection is a medical condition where a tear develops in the lining of the aorta, which can lead to further complications and death if untreated. The most common treatment is thoracic endovascular aortic repair (TEVAR), which involves implanting a stent graft to reinforce and help heal the compromised aortic wall.

Commonly, the stent can introduce another tear, called a distal stent graft-induced new entry (dSINE), which can require reintervention in some cases. However, in other scenarios, the dSINE is stable and requires no further action. The biomechanical mechanism that causes dSINE is not well understood, which makes predicting stable versus unstable dSINE cases currently impossible.

Qiao et al. performed computational fluid-structure interaction hemodynamics on clinical images of six patients with early dSINE to identify factors that could influence further dSINE deterioration.

“Previous studies have either adopted a rigid wall assumption, ignoring wall deformation, or used finite element analysis, ignoring the effect of blood flow,” said author Kun Luo. “In this study, the fluid-structure interaction method is applied to capture the relationship among the pulsatile blood flow, stent-graft, and aortic vessel wall.”

The researchers examined several biomechanical factors and found commonly used indicators, such as low time-averaged wall shear stress and oscillatory shear index, were insufficient to predict dSINE deterioration. Instead, they identified relative residence time and endothelial cell activation potential as more successful predictive tools.

The authors are planning to expand their patient pool and build on this pilot study by conducting a more in-depth quantitative analysis.

Source: “Biomechanical mechanism of distal stent-graft-induced new entry deterioration after thoracic endovascular aortic repair,” by Yonghui Qiao, Jingyang Luan, Le Mao, Jianren Fan, Ting Zhu, and Kun Luo, Physics of Fluids (2022). The article can be accessed at https://doi.org/10.1063/5.0104649 .