The goal of this observational study is to learn more about the diagnosis of coronary endothelium function and coronary vasospasm using a dedicated invasive protocol in patients who has angina without obstruction in their main heart arteries. The main question it aims to answer is the feasibility, reproducibility, and safety of this invasive protocol:
Does this invasive protocol diagnose coronary endothelial dysfunction and vasospasm without issues?
Participants already having invasive coronary angiogram and physiological studies will undergo additional physiological measurements during the same procedure.
Participants will enrol in a symptoms and quality of life questionnaire using dedicated questionnaires and a mobile application to assess the burden of their symptoms before and after the invasive procedure and up to 12 months follow up.
A subset of participants will undergo a repeat set of these measurements to assess reproducibility of the invasive protocol.
A subset of the participants will also undergo a cardiac MRI to assess correlation with the invasive protocol measurements.