Compute FFR = Pd / Pa (at maximal hyperemia). >0.80 non-ischemic; ≤0.80 PCI indicated. Derived from Pijls 1996, FAME, FAME 2, ESC/EACTS 2018, ACC/AHA 2021, StatPearls. Not medical advice.
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Tool usage guide
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Key facts
Category
Health
Input types
number
Output type
json
Sample coverage
4
API ready
Yes
Overview
The Fractional Flow Reserve Calculator computes FFR from distal coronary pressure (Pd) and aortic pressure (Pa) measured at maximal hyperemia using FFR = Pd / Pa. Results include the pressure gradient, FFR value, percentage, and a non-ischemic or ischemic category. This tool is for reference only and is not medical advice.
When to use
Calculate FFR from paired Pd and Pa measurements recorded at maximal hyperemia.
Review the hemodynamic significance of a coronary stenosis using the 0.80 threshold.
Check the pressure gradient and rounded FFR result for clinical documentation or discussion.
How it works
1Enter distal coronary pressure Pd in mmHg from a pressure wire measurement.
2Enter aortic pressure Pa in mmHg measured at the same time and during maximal hyperemia.
3The calculator divides Pd by Pa and calculates the pressure gradient as Pa − Pd.
4The result is labeled non-ischemic when FFR is above 0.80 or ischemic when FFR is 0.80 or lower, using the selected decimal places.
Use cases
Interventional cardiology teams can verify FFR calculations from pressure-wire measurements.
Clinicians can review whether a measured FFR falls above or below the 0.80 reference threshold.
Medical educators and trainees can demonstrate how Pd and Pa produce an FFR value and pressure gradient.
Examples
1. Non-ischemic FFR calculation
Interventional cardiology trainee
Background
A pressure-wire assessment records a distal coronary pressure of 88 mmHg and an aortic pressure of 100 mmHg at maximal hyperemia.
Problem
Calculate the FFR and determine which category the result falls into.
How to use
Enter Pd as 88, Pa as 100, and set Decimal Places to 3.
Pd: 88 mmHg; Pa: 100 mmHg; Decimal Places: 3
Outcome
FFR = 88 / 100 = 0.880, with a 12 mmHg pressure gradient. The result is categorized as Non-ischemic.
2. Ischemic FFR calculation
Cardiology fellow
Background
A coronary pressure assessment records Pd of 68 mmHg and Pa of 100 mmHg during maximal hyperemia.
Problem
Quantify the pressure ratio and identify whether the result is above or below the 0.80 threshold.
How to use
Enter Pd as 68, Pa as 100, and use 3 decimal places.
FAQ
What is the FFR formula?
FFR is calculated as Pd divided by Pa, where Pd is distal coronary pressure and Pa is aortic pressure.
What inputs does the calculator require?
It requires Pd and Pa values in mmHg measured at the same time during maximal hyperemia.
How is the FFR result categorized?
FFR above 0.80 is categorized as non-ischemic; FFR of 0.80 or lower is categorized as ischemic.
Can I control the displayed precision?
Yes. You can select the number of decimal places from 0 to 8; the default is 3.
Is this calculator medical advice?
No. It provides a mathematical FFR calculation and should not replace clinical assessment or professional medical judgment.