In the 1950s, DeBakey's observations and classification of atherosclerotic blood vessels permitted innovations in the treatments of vascular disease. His pursuit of the ideal material to make grafts led him to a department store that had run out of nylon, so he settled on polyethylene terephthalate (Dacron) and bought a yard of the material. Using his wife's sewing machine, DeBakey produced the first arterial Dacron grafts to replace or repair blood vessels. He subsequently collaborated with a research associate from the Philadelphia College of Textiles and Science to create a knitting machine for making grafts.