To the Editor,The authors state an important bias about studies comparing different graft types in different regions entitled “Longterm patency of autogenous saphenous veins vs. PTFE interposition graft for prosthetic hemodialysis access.” published in Anatol J Cardiol 2014; 14: 542-6. (1). As mentioned in the study, the selection of the anastomosis region was based on the calibration of the arteries and veins (1). Both PTFE and saphenous vein grafts were used above the wrist in our study because of inadequate calibration of veins and arteries; thus, we did not compare in “very” different regions. Among the complications, infections or other severe complications were not observed in both groups. This issue was described in detail in the study.The other question of the authors is about the patency that is in close relationship with the localization. PTFEs were used only between the brachial artery and high brachial vein. The reason for this selection was the diameter of the graft. Because thinner PTFEs are more likely to be thrombosed, the selected grafts were at least in 6 mm in diameter. The main finding of our study is the limited patency of the PTFE compared with saphenous veins, although they were used in larger calibers and anastomosed between larger vessels.