To achieve optimal long-term clinical results after percutaneous coronary intervention (PCI), adequate deployment of stents is essential. Thorough expansion of the stent and full apposition of stent struts against the vessel wall are determining factors for preventing stent thrombosis and restenosis for bare-metal as well as drug-eluting stents (DES). Standard coronary angiography is limited in assessing accurate vessel size and characterizing tissues and calcium load. Therefore, stent underexpansion frequently occurs after stent deployment. Post-dilation is often performed to achieve optimal stent expansion and reduce stent malapposition of stent struts, aiming to reduce stent thrombosis and restenosis both short term as long term. However, there are limited studies that have explored the effect of post-dilatation for stent optimization on clinical outcomes. As a result of the restricted evidence, there is no consensus whether post-dilatation should be used routinely in clinical practice and the extent to which post-dilatation is being utilized remains unclear. For this reason, the OPTIMIZE PCI was designed, a national registry-based quality improvement project to implement a liberal post-dilatation strategy in multiple PCI centers in the Netherlands. As part of the OPTIMIZE-PCI, a retrospective observational analysis will eventually be conducted to evaluate whether adopting this strategy has led to improved clinical outcomes after PCI in terms of major adverse cardiac events.