There is still considerable risk when performing anastomotic procedures in the aorta and artificial vessels. The wrapping method is occasionally used as an alternative to solve the problems of hemostasis and reinforcement of the anastomotic portion, however, few data are available on the results of long-term follow up after anastomosis in this area. To define the long-term results for the wrapping method, we evaluated changes in the vascular walls of set intervals. The purpose of this study was to analyze the influence of technical factors and to sutisfy the prerequisites for an ideal wrapping method. A total of 26 mongrel dogs of both sexes were used in this study. We examined changes of the aortic walls microscopically of set intervals after a wrapping method using woven Dacron materials for 4 weeks and 4 months. Another 2 groups (Mesh group and E-PTFE group) were also included in this study. The cause of thinning phenomena of the aortic walls appears to be compression of the anastomotic portion. Wrapping materials resulting in excessively small diameters may cause deleterious compressions of the anastomotic site. Wrapping methods with materials ensuring a larger diameter may play an important role after anastomotic operations for reinforcement and hemostasis.