Differences and Correlations of Morphological and Hemodynamic Parameters between Anterior Circulation Bifurcation and Side-wall Aneurysms.

OBJECTIVE: The objective of this research was to explore the difference and correlation of the morphological and hemodynamic features between sidewall and bifurcation aneurysms in anterior circulation arteries, utilizing computational fluid dynamics as a tool for analysis. METHODS: In line with the designated inclusion criteria, this study covered 160 aneurysms identified in 131 patients who received treatment at Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, China, from January 2021 to September 2022. Utilizing follow-up digital subtraction angiography (DSA) data, these cases were classified into two distinct groups: the sidewall aneurysm group and the bifurcation aneurysm group. Morphological and hemodynamic parameters in the immediate preoperative period were meticulously calculated and examined in both groups using a three-dimensional DSA reconstruction model. RESULTS: No significant differences were found in the morphological or hemodynamic parameters of bifurcation aneurysms at varied locations within the anterior circulation. However, pronounced differences were identified between sidewall and bifurcation aneurysms in terms of morphological parameters such as the diameter of the parent vessel (Dvessel), inflow angle (θF), and size ratio (SR), as well as the hemodynamic parameter of inflow concentration index (ICI) (P<0.001). Notably, only the SR exhibited a significant correlation with multiple hemodynamic parameters (P<0.001), while the ICI was closely related to several morphological parameters (R>0.5, P<0.001). CONCLUSIONS: The significant differences in certain morphological and hemodynamic parameters between sidewall and bifurcation aneurysms emphasize the importance to contemplate variances in threshold values for these parameters when evaluating the risk of rupture in anterior circulation aneurysms. Whether it is a bifurcation or sidewall aneurysm, these disparities should be considered. The morphological parameter SR has the potential to be a valuable clinical tool for promptly distinguishing the distinct rupture risks associated with sidewall and bifurcation aneurysms.

Efficacy and Safety of Willis Covered Stent for Treatment of Complex Vascular Diseases of the Internal Carotid Artery.

BACKGROUND: Willis covered stents are used in clinical practice for some complex cerebrovascular diseases. However, the performance of the Willis covered stent requires further investigation. In this study, we investigate the safety and efficacy of Willis covered stents for the treatment of complex vascular diseases of the internal carotid artery (ICA). METHODS: Thirteen patients with complex ICA diseases treated with the Willis covered stent system at our institution from October 2016 to January 2018 were analyzed retrospectively. Follow-up observation and digital subtraction angiography (DSA) examination were conducted at about 6-10 months after the treatment. RESULTS: The complex vascular diseases of the ICA were successfully treated in 12 patients. The technical success rate was 92.3%. Pathologically, 13 lesions included blood blister-like aneurysm (n = 7), traumatic pseudoaneurysm (n = 1), traumatic carotid artery rupture (n = 1), and aneurysm with arteriovenous fistula (n = 4). Thirteen patients with complex vascular diseases of the ICA were treated with 15 Willis covered stents. The release sites of Willis covered stents were the C7 (n = 2), C6 (n = 1), C5 and/or C4 (n = 9), and the C2 (n = 3) segment of the ICA. DSA performed immediately after stent deployment revealed that complete occlusion of the lesion was achieved in 11 patients and endoleak was observed in 2 patients. Of the 11 patients, postoperative DSA examination indicated that the lesions were occluded completely. Among 2 patients, who had a second stent implantation at the break of the ICA, the traumatic ICA rupture was essentially completely obstructed in 1 patient. The endoleak remained in 1 patient with carotid cavernous sinus fistula because the placement of the second stent system was difficult with his ICA tortuosity. No recurrence of aneurysms, hemorrhagia, and other lesions was observed, and the patients' parent arteries were patent without stenosis. No procedure-related complications or deaths occurred during follow-up. CONCLUSIONS: For the treatment of complex vascular diseases in the ICA, Willis covered stent implantation is safe and effective. However, longer follow-up, large-sample controlled studies, and multicenter studies are needed for further confirmation.