Internal mammary artery (IMA) graft protection with nonbiodegradable material, such as polytetrafluorethylene (PTFE), is recognized as an effective means for preventing overexuberant adhesion development as well as injury of retrosternally crossing arterial grafts in the event of resternotomy and should enable better identification of the IMA graft. It is still uncertain whether the use of PTFE material is suitable for diabetic patients with complete arterial revascularization due to potential infectious complications. We report on a young diabetic patient after arterial T-grafting due to severe coronary disease and readmission with wound infection and retrosternal fistula formation 8 months after operation.