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Clinical judgment important in FFR uncertainty zone
Clinicians should make revascularization decisions based on broadened clinical judgment when a single fractional flow reserve result falls within an uncertainty zone of 0.75 and 0.85, and particularly between 0.77 and 0.83, when measurement certainty falls to less than 80%, study investigators found.
To evaluate the effects of FFR measurement variability on treatment strategy, researchers analyzed data from the landmark DEFER trial, which involved two repeated FFR measurements in the same lesion, 10 minutes apart, and calculated the standard deviation of the difference between them. They then established measurement certainty, defined as the probability that the FFR-guided revascularization strategy would not change if the test is repeated 10 minutes later across the entire range of FFR values, from 0.2 to 1.
Outside the FFR range of 0.75 to 0.85, measurement certainty of a single result was more than 95%. However, certainty fell to less than 80% within the range of 0.77 to 0.83, falling to its lowest point of 50% around 0.8. Researchers noted that each time a single FFR value would fall between 0.75 and 0.85, the FFR-derived revascularization recommendation might change if the measurement is repeated 10 minutes later, with this chance increasing the closer the FFR result is to 0.8.
“Within this range, it would be particularly relevant to use all available information (including other perfusion imaging modalities, considering anatomical features and risk-benefit profile) to deliver safe and suitable care for individual patients,” the researchers wrote.
Disclosure: The researchers report no relevant financial disclosures.