Fractional flow reserve (FFR) measurement involves determining the ratio between the maximum achievable blood flow in a diseased coronary artery and the theoretical maximum flow in a normal coronary artery. An FFR of 1.0 is widely accepted as normal. An FFR value lower than 0.75 - 0.80 is generally considered to be associated with myocardial ischemia (MI).~FFR is easily measured during routine coronary angiography by using a pressure wire to calculate the ratio between coronary pressure distal to a coronary artery stenosis and aortic pressure under conditions of maximum myocardial hyperemia. This ratio represents the potential decrease in coronary flow distal to the coronary stenosis.~Over the past decade, FFR measurement has been increasingly used in cardiac catheterization laboratories. It provides a quantitative assessment of the functional severity of a coronary artery stenosis identified during coronary angiography and cardiac catheterization.~Opsens, Inc. has developed a new pressure wire for use in determining FFR in coronary arteries; the OptoWire. The OptoWire is an instrumented guide wire with a fiber optic pressure sensor mounted 3.5 cm proximal to the tip. The Optowire measures blood pressure during diagnostic and/or interventional procedures when used in combination with the OptoMonitor.~The O2 study is a pilot study which aims to provide preliminary experience in human patients with coronary artery disease. The study data will also be used as part of design validation.~The O2 study is a prospective single arm study designed to assess the usability, functionality, and safety of the Optowire and Optomonitor in patients.
The purpose of this study is to assess the usability and safety of the Opsens OptoWire and Optomonitor in measuring fractional flow reserve (FFR) in patients with coronary artery disease who are undergoing a coronary angiogram.