During surgery for acute aortic dissection, reinforcing anastomoses in the aorta with felt strips is helpful for hemostasis. We had two cases of hemolytic anemia that developed due to inversion of an inner felt strip that was applied at the proximal anastomosis in the ascending aorta. A 78-year-old woman underwent ascending aorta replacement for type A aortic dissection, and over the next 2.5 years, she gradually developed hemolytic anemia and underwent reoperation. A 47-year-old woman also had to undergo reoperation due to hemolytic anemia 17 days after ascending aorta replacement for type A aortic dissection. Based on these experiences, we make suture line in the felt much more proximal, and no further cases of hemolytic anemia have occurred since then.