TOPLINE

Lower values of coronary CT angiography-derived fractional flow reserve (FFR-CT) were associated with an increased risk for cardiovascular events and death over 3 years, independent of standard risk factors and the severity of stenosis.

METHODOLOGY

• Researchers used data from a retrospective, observational cohort study (FISH&CHIPS) to assess whether FFR-CT was associated with future cardiovascular events.
• They identified adults who underwent coronary CT angiography for suspected coronary artery disease across 27 hospitals in England from 2017 to 2020. The final analysis included 7836 patients with clinically indicated FFR-CT (median age, 63 years; 37.4% women).
• The analysis computed stenosis-specific FFR-CT, measured 2 cm distal to a stenosis of 30% and more in any vessel measuring at least 1.8 mm, and distal FFR-CT. Values were grouped as normal (> 0.80), borderline (0.71-0.80), reduced (0.51-0.70), or severely reduced (≤ 0.50).
• Researchers used hospital and mortality records to track the occurrence of myocardial infarction (MI), revascularization, cardiovascular death, and all-cause death, over a median follow-up of 3.1 years.
• Analyses were adjusted for common cardiovascular risk factors and CT stenosis severity.

TAKEAWAY

• Both reduced and severely reduced values of stenosis-specific FFR-CT were associated with a 3.13-fold higher adjusted risk for MI (P < .001 for both). The severely reduced value was associated with a 2.92-fold higher adjusted risk for cardiovascular death (P = .02).
• The lower values of stenosis-specific FFR-CT were associated with a progressively higher risk for revascularization, with adjusted hazard ratios ranging from 4.39 for borderline values to 22.30 for severely reduced values (P < .001 for all).
• Adding stenosis-specific FFR-CT to a model with clinical risk factors and CT stenosis improved the C-index for discriminating MI or cardiovascular death (P < .001). Using stenosis-specific FFR-CT as a continuous value, 0.67 was identified as the optimal cutoff to predict risk for nonfatal MI or cardiovascular death.
• Distal FFR-CT showed associations with outcomes similar to stenosis-specific FFR-CT, with discordance noted in 36.4% of cases.

IN PRACTICE

"Discordance between stenosis-specific and distal FFR-CT is common, but in most cases, it would be reasonable to focus on stenosis-specific FFR-CT values for both diagnosis and prognosis of flow-limiting CAD [coronary artery disease]," the researchers wrote.

SOURCE

The study was led by Jack S. Bell, BM, BCh, of Liverpool Heart and Chest Hospital in Liverpool, England. It was published online on September 22 in Circulation.

LIMITATIONS

The study was observational; thus, the results of FFR-CT may have influenced later care. Researchers could not distinguish MI events that occurred during the procedures from those that occurred later during the same hospital stay. They lacked data on the burden of plaque, smoking, and family history.

DISCLOSURES

The study received sponsorship from the Liverpool Heart and Chest Hospital. The FFR-CT analyses were performed by HeartFlow. The sponsor and HeartFlow Inc. had a collaboration agreement, although HeartFlow did not fund the study. Two authors reported being employees of HeartFlow, and one author reported having share options and providing consultancy to HeartFlow. The FISH&CHIPS study received funding from the UK Medical Research Council.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.