Abstract
Background
Computational pressure-flow dynamics derived fractional flow reserve (caFFR) is a novel index developed to evaluate the extent of myocardial ischemia in patients with coronary artery disease (CAD), which eliminates the need of invasive pressure guidewire and hyperaemic stimulus in conventional fractional flow reserve (FFR) measurement. Studies have shown improved clinical outcomes associated with adherence to functional myocardial ischemia assessment when deciding to perform percutaneous coronary intervention (PCI) at a per-patient level. However, the clinical significance of such treatment adherence at a per-vessel level remains uncertain.
Methods
A total of 928 patients (mean age 66.2±10.5, male 72.7%) with stable CAD were included in this study. The caFFR of all three major coronary vessels were obtained for every patient, and the FFR threshold of 0.8 was adopted as the threshold for caFFR to indicate functionally significant artery stenosis which warrants PCI, and vice versa. Based on the caFFR of each major coronary vessel and whether PCI was performed to the respective vessel, patients were stratified into 0–1 vessel with treatment adherence group (group 1) (n=105), 2 vessels with treatment adherence group (group 2) (n=338), and 3 vessels with treatment adherence group (group 3) (n=485). The primary endpoint was major adverse cardiac events (MACE), defined as a composite of all-cause mortality, non-fatal myocardial infarction and any subsequent revascularization.
Results
The severity of CAD based on SYNTAX score assessment was 18.6±10.2 in group 1, 14.6±8.9 in group 2, and 11.5±9.9 in group 3 (P<0.001). The rates of MACE at 3 years were significantly different across groups 1, 2 and 3 (17.1% vs. 12.1% vs. 7.4%; P=0.004). With reference to group 3, the risk of MACE at 3 years was increased in group 2 (adjusted hazard ratio [HR]=1.597; 95% confidence interval [CI]=1.020–2.501; P=0.041), and further increased in group 1 (adjusted HR=1.933; 95% CI=1.081–3.457; P=0.026).
Conclusion
In stable CAD patients, the risk of MACE is incremental when fewer major coronary vessels are treated with adherence to caFFR threshold of 0.8. Per-vessel treatment adherence significantly affects clinical outcomes in terms of MACE.
FUNDunding Acknowledgement
Type of funding sources: None.
Novel Indices of Coronary Physiology
