During coronary catheterization, a catheter is inserted into the femoral (groin) or radial arteries (wrist) using a sheath and guidewire.<unk>  uses a small sensor on the tip of the wire (commonly a transducer) to measure pressure, temperature and flow to determine the exact severity of the lesion. This is done during maximal blood flow (hyperemia), which can be induced by injecting products such as adenosine or papaverine. A pullback of the pressure wire is performed, and pressures are recorded across the vessel. There is no absolute cut-off point at which<unk>  becomes abnormal; rather, there is a smooth transition, with a large grey zone of insecurity. In clinical trials however, a cut-off point of 0.75 to 0.80 has been used; higher values indicate a non-significant stenosis, whereas lower values indicate a significant lesion.
Fractional flow reserve
Coronary flow reserve
Pressure reactivity index
Instantaneous wave-free ratio
Impedance cardiography
Arterial resistivity index
Tissue Doppler echocardiography
Intracoronary optical coherence tomography