Objective To investigate the protective effects of fasudil hydrochloride on endothelial cell injury in coronary heart disease with slow blood flow patients who underwent percutaneous coronary intervention (PCI). Methods From May 2015 to August 2016, 120 cases coronary heart disease with slow blood flow patients with who underwent PCI were enrolled into our study and randomly divided into 2 groups: 60 patients in the treatment group and 60 patients in the control group. All patients were treated with the conventional treatment. The patients in the treatment group were treated with fasudil hydrochloride based on the conventional treatment. Both groups had been treated for 2 weeks. The endothelial cell injury indexes and inflammatory indexes were compared between 2 groups before and after treatment. After 3 months’ follow-up, the cardiovascular adverse events occurred in 2 groups were recorded and compared. Results Before treatment, there was no differences in plasma endothelial microparticles (EMPs), vascular von wille brand factor (vWF), endothelin-1 (ET-1), nitric oxide (NO), endothelial nitric oxide synthase (eNOS), flow mediated dilation (FMD), nitroglycerin-mediated dilation (NMD), interleukin 6 (IL-6), C-reactive protein (CRP) and tumor necrosis factor alpha (TNF-α) between 2 groups (P?