Fractional flow reserve (FFR) measurement involves determining the ratio between the maximum achievable blood flow in a diseased coronary artery and the theoretical maximal flow in a normal coronary artery. An FFR of 1.0 is widely accepted as normal. An FFR value less than or equal to 0.80 is generally considered to be associated with myocardial ischemia.~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 o the coronary stenosis. Recently, other physiology ratios called non-hyperemic ratios (NHPR) have been developed.~Both types of physiology measures (FFR and NHPR) have been increasingly used in cardiac catheterization laboratories as a diagnostic tool. They provide a quantitative assessment of the functional severity of a coronary artery stenosis identified during coronary angiography and cardiac catheterization. However, they are underutilized as tools for the assessment of success of coronary interventions.~The PREDICT study is a pilot study which aims to prospectively determine whether post-PCI physiology guidance is associated with better clinical outcomes than standard angiographic guidance.
The purpose of this study is to assess whether the use of physiology parameters as guidance post-percutaneous coronary interventions (PCI) is associated with less risks of target vessel failure (TVF) and angina-related events than standard angiographic guidance.