Coronary artery disease (CAD) is commonly treated using percutaneous coronary interventions (PCI). However, PCI with stent placement damages the endothelium, and failure to restore endothelial function may result in PCI failure with poor patient outcomes. Oxidative signalling is central to maintaining endothelial function. Potentiation of oxidant production, as observed post-PCI, results in endothelial dysfunction. This review delves into our current understanding of the physiological role that endothelial-derived oxidants play within the vasculature and the effects of altered redox signalling during dysfunction. We then examine the impact of PCI and intra-coronary stent placement on oxidant production in the endothelium, which can culminate in stent failure. Finally, we explore how recent advances in PCI and stent technologies aim to mitigate PCI-induced oxidative damage and improve clinical outcomes. Current PCI technologies exacerbate cellular oxidant levels, driving endothelial dysfunction. If left uncontrolled, oxidative signalling leads to increased intravascular inflammation, restenosis, and neoatherosclerosis. Through the development of novel biomaterials and therapeutics, we can limit PCI-induced oxidant production, allowing for the restoration of a healthy endothelium and preventing CAD recurrence.