This study (OxOPT-PCI) investigates if the use of blood flow measurements (namely measurement of fractional flow reserve (FFR)) and intravascular imaging (namely optical coherence tomography (OCT)) after the implantation of a stent can improve the treatment result for these patients. Both, FFR and OCT are being used already in daily clinical routing but their usefulness especially in combination is not clear. In order to standardise the optimisation procedure we developed a specific algorithm to make sure that all patients receive the same optimisation measures based on the assessment of FFR and OCT.