<qa>  What is the effect of pretreatment with intravenous Alprostadil on the incidenceThe aim of this prospective, randomized, controlled study is to investigate the effect of pretreatment with intravenous Alprostadil on the incidence of CIN in a high-risk population of patients with both type 2 diabetes mellitus T2DM and CKD undergoing coronary angiography, and evaluate the influence of such potential benefit on short-term outcome. 