Computational fluid dynamics evaluation of physician-modified stent graft repair for distal residual stanford type B aortic dissection.

BACKGROUND: Few studies have focused on physician-modified stent grafts (PMEGs) for treating distal residual dissection in type B aortic dissection (TBAD). This study aimed to assess the usage of PMEGs in the treatment of distal residual dissection of TBAD by analyzing the relevant hemodynamical indicators.

METHODS: Patients with TBAD underwent thoracic endovascular aortic repair surgery in the first stage, and in the second stage PMEGs were used to repair the residual dissection. Computational fluid dynamics and three-dimensional structural analyses were performed, based on computed tomography angiography datasets. The prognostic post-implantation improvement was studied using both quantitative and qualitative functional analysis.

RESULTS: A total of 30 patients with TBAD were enrolled. Following the PMEGs procedure, peak systolic pressure in all aortic segments trended downward without statistical significance. Overall time-averaged wall shear stress (TAWSS) increased significantly (P = 0.007), especially in the S2 segment (P = 0.005), while overall oscillatory shear index decreased significantly (P = 0.010). Superior mesenteric artery blood flow was significantly higher postoperatively (P = 0.005), with no significant differences in other visceral branches. At 1‑year follow-up, false lumen volume was markedly reduced (P < 0.001) and true lumen volume increased, suggesting favorable aortic remodeling.

CONCLUSIONS: The PMEGs technique effectively ameliorates hemodynamic parameters in patients with residual distal dissection following TBAD. However, long-term follow-up of the increase in TAWSS is still required.