The purpose of this investigation is to see if the newly developed "iKOs™ microcatheter" can safely and accurately measure flow and pressure within the heart arteries of 10 patients undergoing angiogram and pressure wire tests.

After being informed about the study and the potential risks and benefits, participants who provide written consent will be screened to make sure they fulfil the study entry requirements. Those who are assessed as eligible will undergo baseline assessments and preparation for their angiogram.

Once enrolled they will undergo coronary angiography at the start of their clinical procedure. The angiogram will be examined by the Investigator and a decision made if the target vessel is suitable for a pressure wire study and insertion of the investigational device. If the investigator confirms that the participant remains eligible and the study part can go ahead, the participant will proceed to undergo the investigation with the iKOs microcatheter.

The study assessments will be performed through the right radial artery (preference) under local anaesthesia. A sheath will be inserted and a pre-procedure blood sample taken for Troponin T level. A pressure study will then be performed, initially with a pressure wire before using the iKOs™ microcatheter. Both will be performed before and after hyperaemia. Following withdrawal of the iKOs™ microcatheter, a pressure wire assessment is then repeated after the microcatheter is withdrawn. The case will then proceed as clinically indicated. The whole procedure should take about 30-45 minutes. Post-procedure the participant will be managed according to standard clinical practice.

The participant will be discharged home, usually about 4 hours after the end of the procedure. A troponin blood test and ECG will be repeated before they are discharged.

Follow up telephone calls to assess for any complications of the procedure will be made within the first 7 days and again between 6 and 8 weeks after the procedure.

Inclusion Criteria:

• Able and willing to give informed consent
• >18 years old
• Have a clinical diagnosis of coronary artery disease
• Undergoing further assessment of a coronary artery with a pressure wire study

Exclusion Criteria:

General

• Previous coronary artery bypass grafting.
• Non/ST-elevation myocardial infarction as indication for angiography.
• Ongoing evidence of ischaemia at rest.
• Severe renal impairment (GFR <25).
• Severe anaemia (Hb <10).
• Heparin allergy.
• Atrial fibrillation.
• Contraindication to adenosine.
• Pregnant or lactating; or female of childbearing potential.
• Participation in other interventional studies.

Additional exclusion criteria at Angiogram:

• Critical coronary artery stenosis in the vessel which is to be studied (>90%).
• Left main stem coronary disease causing a >50% stenosis.
• Triple vessel coronary disease.