A sheath and guidewire are used to introduce a catheter during cardiac catheterization into the femoral (groyne) or radial arteries (wrist). In order to pinpoint the precise degree of the lesion, Fractional Flow Reserve uses a tiny sensor at the wire's tip called a transducer to detect pressure, temperature, and flow. This is carried out during hyperemia, which can be brought on by injecting substances like adenosine or papaverine. Pressures are measured throughout the vessel after a retraction of the pressure wire. There is no clear cut-off point where FFR ceases to be normal; rather, there is a gradual shift with a sizable area of unpredictability. However, a cut-off point of 0.75 to 0.80 has been utilised in clinical trials; greater values imply.
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