The use of endovascular aneurysm repair (EVAR) strategies for the treatment of complex aortic pathologies is a major area of investigation in modern surgery. EVAR strategies using fenestrated or branched devices provide alternatives to open surgery for patients with aortic pathologies with visceral branch involvement, but their applications have some major limitations. To extend endovascular repair to patients whose anatomy is unfit for branched or fenestrated stent grafts or open repair, parallel graft techniques using chimney grafts (CGs) have been proposed. Several recent series have confirmed that the midterm durability of CGs is similar to that of other endovascular repair techniques. However, the risk of a persistent type 1 endoleak, or gutter endoleak, is a major concern for their further application. In addition, the combinations of CGs with various brands of main aortic graft (MAG) that are applicable for use in patients remain unclear. This study aimed to determine the radial forces developed by different brands of MAG and their effects on CGs, and the real gutter condition produced between the CGs and main stent grafts.