Rationale: coronary microvascular disease is a relatively 'new' entity within the field of cardiology. The investigators are able to investigate the microcirculation by measurements performed in the catheterization laboratory. But even though measurements are performed on a daily basis, a lot of questions regarding microvascular disease remain. The rationale of this registry is to get an overview of patients and measurement values in daily routine practice.

Objective and main endpoint: No previous registries have been set-up where coronary blood flow and resistance was systematically stored. Therefore the analyses will be mainly descriptive. The objective is to acquire a better insight in the indications and use of this technique in everyday practice , its consequences for clinical decision making, and to enable interventionalists to exchange mutual knowledge about this specific methodology and about the coronary microcirculation in general.

Study design: prospective registry

Study population: All patients who underwent coronary angiography with or without coronary intervention for any reason and if an indication for the foreseen intracoronary physiologic measurements is present according to the discretion of the operator.

Intervention (if applicable): none, only usage of measurement data. The only 'intervention' for all patients is a questionnaire.

This registry only collects all measurement data from normal/routine physiologic assessment in the cathlab. These measurements are performed on a daily basis. The following paragraph will explain these routine measurements briefly.

Short description of the procedure Coronary angiography, PCI (if indicated), and physiologic measurements are performed completely according to normal routine. Physiologic measurements may include FFR, NHPR, IMR, CFR, absolute flow (Q) and microcirculatory resistance (Rmicro or MRR) measurement.

Intention to measure Q and Rmicro are mandatory to be included in this registry.

If there is failure to measure Q and/or Rmicro , it should be carefully noted including the reason for failure.

Coronary physiologic measurements may be performed either prior or after PCI, if applicable. If they are performed before PCI, it is recommended (according to Good Clinical Practice) but not absolutely mandatory to repeat these measurements also after PCI.

As said, the invasive procedure itself, including all measurements, should be performed completely according to clinical routine. Use of drugs either during or after the procedure should also exactly identical to normal routine.

Inclusion criteria:

• All patients are eligible for participation in this registry if they are undergoing coronary angiography with or without coronary intervention for any reason and if an indication for the foreseen intracoronary physiologic measurements is present according to the discretion of the investigating operator.
• >18 and <90 years of age
• able to give informed consent

Exclusion criteria:

- There are no specific exclusion criteria other than contraindications for physiologic measurements in general.

see above