Fractional flow reserve (FFR) is the current gold standard for correct decision making with respect to revascularization in the catheterization laboratory. FFR is measured by using a pressure guidewire equipped with a pressure sensor, positioned distal to the stenosis under investigation. A newly developed pressure wire using open wire technology has recently become commercially available. The purpose of this study is to evaluate whether the Wirecath pressure guidewire can be used as standard pressure guidewire.

The effectiveness of the device will be investigated by comparing Wirecath FFR measurements with the measurements of another regular sensor-tipped pressure guidewires during simultaneous FFR measurements in the same vessel.

FFR is a lesion-specific pressure-derived index of functional severity, defined as the maximum myocardial blood flow in the presence of an epicardial stenosis compared with the maximum flow in the hypothetical absence of the stenosis. FFR is measured by advancing a pressure guidewire into the coronary artery distal to the lesion under investigation and maintained in that position. Distal coronary pressure (Pd) and aortic pressure (Pa) are measured simultaneously while inducing steady state maximum hyperemia. FFR is defined as the lowest value of Pd/Pa achieved during maximum hyperemia. An FFR value = or < 0.80 indicates the presence of myocardial ischemia and indicates PCI is warranted.

Existing 0.014" wires with pressure measurement capabilities have been available for more than 20 years. Improvements have been done over time, but they are still regarded as inferior to ordinary guidewires when it comes to maneuverability and general guidewire properties. This is attributed to the microelectronics that are needed to facilitate the pressure measurements in these wires. These existing wires also have issues with signal stability which is often referred to as 'drift'. Drift is an electronical phenomenon that leads to a slow progressive change in the pressure value over time. a not entirely reliable signal quality.

A relatively new pressure guidewire, Wirecath, is an equivalent device to the currently commercially available pressure guidewires. In comparative bench tests it has shown very good maneuverability. Moreover due to the 'open wire' technology (and thus lack of microelectronics throughout the wire), the Wirecath has very stable signal properties and is, according to physical law and bench testing, immune against a hydrostatic error and less affected by drifting of the signal, which are limitations with current pressure guidewires.

This study is designed to examine and compare the pressure measurements of two commercially available pressure guidewires (Abbott and Cavis Technologies) by simultaneously measuring FFR in the same coronary artery with two different pressure guidewires.

Inclusion Criteria:

• Age 18-80 years
• Scheduled to undergo invasive FFR measurement
• Coronary artery lesions located in the proximal or mid part of the coronary artery
• Reference diameter of at least 2.0mm

Exclusion Criteria:

• Severe aortic valve stenosis
• known conduction disturbances (second- or third-degree AV block)
• acute myocardial infarction (CK >1,000 U/L less than 5 days ago)
• bradycardia (less than 45 beats/min)
• severe hypotension
• extremely tortuous or calcified coronary arteries precluding FFR measurement
• history of severe asthma
• pregnancy
• inability to provide informed consent.

There is no plan to make individual (non-anonymized) participant data available to others.