The<unk>  (iFR, sometimes referred to as the instant<unk> -free<unk>  or instant flow reserve) is a diagnostic tool used to assess whether a stenosis is causing a limitation of blood flow in coronary arteries with subsequent ischemia. iFR is performed during cardiac catheterisation (angiography) using invasive coronary pressure wires which are placed in the coronary arteries that are to be assessed. Pressure wires are commonly used by interventional cardiologists to guide decisions to perform revascularization, either by stenting or bypass surgery.
Instantaneous wave-free ratio
E/A ratio
Pressure reactivity index
Coronary flow reserve
Arterial input function
Fractional flow reserve
Ka/Ks ratio
QRS complex