Internal surfaces of vascular grafts harvested 24 weeks after the surgery. (A) A PU graft showing a smooth and intact surface without thrombus or obvious neointimal hyperplasia. (B) A PTFE graft showing uneven surface and obvious neointimal hyperplasia (yellowish and stiffer).
Hu et al. BMC Cardiovascular Disorders 2012 12:115 doi:10.1186/1471-2261-12-115