An overview of intimal hyperplasia. Many hypotheses have been postulated for the development of intimal hyperplasia in vein and prosthetic grafts. In these hypotheses, the central theme seems to be endothelial injury, but not always denuding injury. As we progress into the biologic era with more sophisticated research tools, the study of the endothelial cell may give us the answers to the problem of intimal hyperplasia. In addition, the leukocyte is still a relatively unknown entity and further modification of their function may hold promise. 