In this episode, we delve into the ILUMIEN IV trial, a significant study comparing optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) with traditional angiography-guided PCI in patients with complex coronary artery disease, including those with diabetes. While OCT guidance led to a larger minimum stent area and a notable reduction in stent thrombosis rates, it did not significantly decrease the two-year rate of target vessel failure compared to angiography guidance. Join us as we explore the trial's design, key findings, and its implications for interventional cardiology practice.