Ischemia is almost always associated with coronary atherosclerosis in patients with chronic coronary artery disease. In addition to morphological factors, the functional factors provide significant effects upon coronary circulation (coronary arteries tone). The degree of narrowing of the coronary arteries may vary depending on smooth muscles tone change in the segment adjacent to atherosclerotic plaque. After stent implantation in coronary artery, diameter of the vessel in prosthetic area remains unchanged, but in artery sites free of stents there remains an adequate tone response to various physiological situations. This heterogeneity of the vascular wall response may affect uniformity of blood flow in a vessel. The coronary circulation may also change under influence of the vessel reactivity due to coated stents implantation, releasing biologically active substances, the diffusion of which in arteries regions adjacent to the stent affects these segments endothelium. The article presents three clinical observations of patients with coronary artery disease after stent implantation, including covered ones.