Clinical outcomes following real-world computed tomography angiography-derived fractional flow reserve testing in chronic coronary syndrome patients with calcification

Aims: This study sought to investigate outcomes following a normal CT-derived fractional flow reserve (FFRCT) result in patients with moderate stenosis and coronary artery calcification, and to describe the relationship between the extent of calcification, stenosis, and FFRCT.

Methods and results: Data from 975 consecutive patients suspected of chronic coronary syndrome with stenosis (30-70%) determined by computed CT angiography and FFRCT to guide downstream management decisions were reviewed. Median (range) follow-up time was 2.2 (0.5-4.2) years. Coronary artery calcium (CAC) scores were ≥400 in 25%, stenosis ≥50% in 83%, and FFRCT >0.80 in 51% of the patients. There was a lower incidence of the composite endpoint (death, myocardial infarction, hospitalization for unstable angina, and unplanned coronary revascularization) at 4.2 years in patients with any CAC and FFRCT > 0.80 vs. FFRCT ≤ 0.80 (3.9% and 8.7%, P = 0.04), however, in patients with CAC scores ≥400 the risk difference between groups did not reach statistical significance, 4.2% vs. 9.7% (P = 0.24). A negative relationship between CAC scores and FFRCT irrespective of stenosis severity was demonstrated.

Conclusion: FFRCT shows promise in identifying patients with stenosis and calcification who can be managed without further downstream testing. Moreover, an inverse relationship between CAC levels and FFRCT was demonstrated. Studies are needed to further assess the clinical utility of FFRCT in patients with extensive coronary calcification.