Neoatherosclerosis is a process of new in-stent atherosclerosis progression, it is now considered a common complication of percutaneous coronary intervention with drug-eluting stent. The development of neoatherosclerosis is a serious matter and can lead to the occurrence of late and very late stent thrombosis. Neoatherosclerosis poses a significant threat and increases the likelihood of experiencing acute coronary syndrome and angina. Paleoatherosclerosis is an advancement of pre-existing atherosclerosis, and it is also able to cause complications after stent implantation. In this review we concentrate on the atherosclerosis impact on stent restenosis and stent thrombosis, focusing on the differences between neoatherosclerosis and paleoatherosclerosis. They can lead to various complications including stent failure, although there is still much uncertainty surrounding these conditions. Numerous risk factors have been recognized that raise the likelihood of neoatherosclerosis progression, including the type of stent, kidney dysfunction, tobacco use, and low-density-lipoprotein (LDL) concentrations. These and other risk factors for neoatherosclerosis and paleoatherosclerosis development ought to be investigated in future studies in order to find causal connections and possible ways of alleviating these conditions.