Diabetic patients represent a high-risk population for coronary artery disease (CAD) and subsequent stent implantation. This abstract summarizes findings from a study evaluating stent expansion and failure rates in diabetic versus non-diabetic patients undergoing percutaneous coronary intervention (PCI). The study aimed to determine if inherent differences in vascular biology or procedural factors contribute to disparities in stent outcomes. We retrospectively analyzed a large cohort of patients who underwent PCI with drug-eluting stents (DES) or bare-metal stents (BMS), stratifying them by diabetic status (type 1, type 2, or non-diabetic). Detailed angiographic and clinical data, including stent diameter, lesion length, vessel characteristics, procedural techniques, and post-procedural follow-up, were collected. Our analysis revealed a significantly higher incidence of suboptimal stent expansion in diabetic patients compared to their non-diabetic counterparts. This was particularly pronounced in patients with longer lesions and calcified vessels, challenging the optimal deployment of stents. Furthermore, diabetic patients exhibited a statistically significant increase in the rate of stent thrombosis, restenosis, and target lesion revascularization (TLR) within the first year post-PCI. Multivariable regression analysis adjusted for confounding factors like age, gender, lesion complexity, and stent type, consistently demonstrated diabetes mellitus as an independent predictor of both inadequate stent expansion and increased stent failure. The increased risk persisted regardless of stent type (DES or BMS), although the absolute risk reduction associated with DES remained evident in both groups. The heightened risk of suboptimal stent expansion in diabetics may be attributed to several factors, including increased vascular stiffness, impaired endothelial function, and chronic inflammation, all hallmarks of diabetic vasculopathy. These findings highlight the need for meticulous procedural planning and optimized stent selection in diabetic patients. Further investigation is required to explore the role of novel imaging modalities and advanced stent designs in mitigating these challenges. Ultimately, a better understanding of the mechanistic underpinnings of impaired stent expansion in diabetic patients is crucial for improving PCI outcomes and reducing morbidity and mortality in this vulnerable population. Future strategies should focus on personalized approaches to PCI tailored to the specific vascular characteristics and clinical profiles of individual diabetic patients.