InstalabFFRCT
Should you take a FFRCT test?
This test is most useful if any of these apply to you.
4 biomarkers included
- FFRCT - LMThe left main is the short trunk feeding both large left-sided arteries. A low value here flags possible flow limitation affecting a large territory, though left main disease is usually confirmed with invasive or intravascular imaging.Why it mattersA low value flags possible flow limitation in the main left trunk, a finding typically confirmed by invasive imaging before treatment.
- FFRCT - LADThe left anterior descending artery supplies the front wall and much of the main pumping chamber. Its value helps separate a visible narrowing from one that truly limits flow.Why it mattersA low value points to flow-limiting disease in the front-wall artery, often a large territory.
- FFRCT - RCAThe right coronary artery usually supplies the lower heart and, in many people, the back wall. Read the value near the narrowing, not just the far tip.Why it mattersA low value points to a narrowing that may limit flow to the lower or back-wall territory.
- FFRCT - LCXThe left circumflex artery wraps around the side of the heart and may supply the back wall. It catches flow problems outside the left main, front, and right-sided readings.Why it mattersA low value points to flow-limiting disease along the side-wall artery.
About FFRCT
A narrowing in a heart artery and a narrowing that limits blood flow are not the same thing. Many narrowings that look worrisome on a scan do not limit flow. This panel sorts your arteries into those two groups.
It uses the images from a coronary computed tomography angiogram you have already had. Software builds a model of your coronary arteries and simulates blood moving through them under stress. What comes back is a flow value along each main vessel, read just downstream of any narrowing. When a vessel has more than one narrowing, each is read on its own.
What This Panel Reveals
The number is called FFRCT, short for fractional flow reserve computed from a coronary scan. It estimates how much pressure remains beyond a narrowing compared with pressure in the main artery leaving the heart. A healthy artery passes pressure through almost unchanged, so the ratio stays near 1.0. A narrowing that chokes flow drops it. The main cutoff is 0.80: at or below that, the vessel is usually treated as flow-limiting.
That 0.80 line is the same one cardiologists use with a pressure wire during a catheter procedure, and the computed version agrees with the wire most of the time. But not perfectly. In the NXT trial, a plain coronary scan correctly cleared about a third of people who did not have flow-limiting disease; adding FFRCT raised that to about four in five.
Reporting a value for each vessel, rather than one summary figure, tells you not just whether you have a problem but where and how much of the heart is affected. Each vessel feeds a different territory of muscle, and the value that matters is the one just past a narrowing, not the lowest point in the vessel.
How to Read Your Results Together
Read the values as a map, not separate verdicts. The pattern across vessels, and how far each number sits from 0.80, is what drives the decision.
| Pattern | What it suggests |
|---|---|
| All vessels above 0.80 | No measured main artery is clearly limiting flow. The work shifts to slowing plaque, not opening an artery. |
| One vessel at or below 0.80 | Possible flow-limiting narrowing in that artery. The next question is whether invasive pressure testing would confirm it. |
| A value between 0.70 and 0.80 | Intermediate range. Small differences around the cutoff are least reliable, so location, symptoms, and artery shape matter. |
| Two or more vessels at or below 0.80 | Multivessel flow-limiting disease. That can change planning from one focal fix to broader stent-or-bypass discussion. |
Values far from 0.80 are the most trustworthy. Above 0.90 strongly argues against a flow-limiting narrowing; below about 0.70 strongly argues for one. The uncertainty lives around the cutoff, which is why 0.79 should not be treated as a world apart from 0.81.
What to Do with Your Results
A vessel at or below 0.80 is the finding that changes management. It is a reason to discuss invasive angiography, where a pressure wire can confirm the result and a stent or bypass can be planned if the anatomy warrants it. An FFRCT value at or below 0.80 has been linked to roughly two to three times the risk of heart attack and cardiovascular death over follow-up. This isn't a number to file away.
If all vessels come back above 0.80, that is strong reassurance. FFRCT-guided strategies have reduced invasive angiography in randomized trials, with similar overall event rates, though a few trials saw a small, non-significant excess of heart attacks in the FFRCT groups that has not been fully explained. But the plaque may still be there. The next move is to slow what is building it: lower apolipoprotein B and lipoprotein(a) if they are high, control blood pressure and blood sugar, and look for inflammation in blood tests.
This is not a test you repeat on a schedule. It answers a specific question at a specific moment: does a narrowing you can see actually limit flow. If your arteries change enough to ask that question again, it is usually because symptoms return or a follow-up scan shows new disease.
When Results Can Be Misleading
Because these numbers are computed from scan images, they inherit the scan's weaknesses. Motion from a fast or irregular heartbeat is a common reason a scan cannot be analyzed. Heavy calcium can blur the artery wall and make the model less reliable; at very high calcium scores the flow reading may add little beyond the plain scan. Even so, a reassuring value above 0.80 still carries good outcomes with heavy calcium, so calcium alone does not rule the test out. The result also has limited use in a vessel with a stent, a bypassed artery, or during an acute heart attack.
One vessel-specific trap is the left anterior descending artery. Its value naturally falls toward the far end, so a low value deep in the vessel without a matching narrowing can be a false alarm. In asymptomatic male marathon runners with no visible narrowing, about a third of far-distal left anterior descending readings were 0.80 or lower. The value has to be read near an actual narrowing, not simply at the lowest point.