The OxOPT-PCI study addresses patients with coronary artery disease who are referred to the John Radcliffe Hospital because of the need for treatment with an intra-coronary stent (metal scaffold) for clinical reasons. Although, this has become a highly standardised procedure it is still challenging for the clinician to assess the final success of this procedure at the end of intervention with conventional methods. This shortcoming can potentially translate into a worse clinical outcome for approximately 10 percent of all patients treated with an intra-coronary stent for this type of disease.