What is it?
FFR is the ratio of pressure beyond a narrowing to the pressure before it, measured with an ultra-thin pressure wire. FFR ≤ 0.80 (or iFR ≤ 0.89) means the stenosis is functionally significant.
Who needs it?
Patients with intermediate narrowings (roughly 40–70%) or multivessel disease where it must be decided which lesion really needs treatment.
How is it done?
The pressure wire is advanced during angiography. FFR uses adenosine to maximise flow; iFR is measured at rest without it. QFR computes the value from the angiogram without any wire.
Before the procedure
Same preparation as angiography; avoid coffee, tea and caffeinated drinks for 12 hours because caffeine blunts adenosine.
After & recovery
If the narrowing is not significant, an unnecessary stent is avoided and medical therapy continues.
Risks & safety
Very safe; adenosine may cause a few seconds of flushing or breathlessness.
Frequently asked questions
Does FFR add cost?
By avoiding unnecessary stents it often lowers overall cost and risk.
FFR vs iFR?
Both assess flow; iFR needs no adenosine and showed similar outcomes in trials.
This content does not replace an examination by your physician. For chest pain or severe shortness of breath, call your local emergency number immediately.