Prognostic Implications of Relative Increase and Final Fractional Flow Reserve in Patients With Stent Implantation

OBJECTIVES The study sought to investigate the prognostic implications of relative increase of fractional flow reserve (FFR) with PCI in combination with post-percutaneous coronary intervention (PCI) FFR. BACKGROUND FFR, measured after PCI has been shown to possess prognostic implications. The relative increase of FFR with PCI can be determined by the interaction of baseline disease pattern, adequacy of PCI, and residual disease burden in a target vessel. However, the role of relative increase of FFR with PCI has not yet been evaluated. METHODS A total of 621 patients who underwent PCI using second-generation drug-eluting stents based on low pre-PCI FFR (<= 0.80) and available post-PCI FFR were analyzed. The relative increase of FFR was calculated by % FFR increase with PCI ([post-PCI FFR - pre-PCI FFR]/pre-PCI FFR x 100). Patients were divided according to the optimal cutoff values of post-PCI FFR (< 0.84) and % FFR increase (<= 15%). The primary outcome was target vessel failure (TVF) (a composite of cardiac death, target vessel-related myocardial infarction, and clinically driven target vessel revascularization) at 2 years. RESULTS Among the total population, 66.0% showed high post-PCI FFR (>= 0.84) and 69.2% showed high % FFR increase (>15%). Patients with low post-PCI FFR showed a higher risk of 2-year TVF than did those with high post-PCI FFR (9.1% vs. 2.6%; hazard ratio [HR]: 3.367; 95% confidence interval [CI]: 1.412 to 8.025; p = 0.006). Patients with low % FFR increase also showed a higher risk of 2-year TVF compared with those with high % FFR increase (9.2% vs. 3.0%; HR: 3.613; 95% CI: 1.543 to 8.458; p = 0.003). Among the high post-PCI FFR group, there were no significant differences in clinical outcomes according to % FFR increase. Conversely, among the low post-PCI FFR group, those with low % FFR increase showed a significantly higher risk of TVF than did those with high % FFR increase (14.3% vs. 4.1%; HR: 4.334; 95% CI: 1.205 to 15.594; p = 0.025). Percent FFR increase significantly increased discriminant and reclassification ability for the occurrence of TVF when added to a model with clinical risk factors and post-PCI FFR (C-index 0.783 vs. 0.734; relative integrated discrimination improvement 0.702; p = 0.009; category-free net reclassification index 0.479; p = 0.031). CONCLUSIONS Percent FFR increase with PCI showed similar prognostic implications with post-PCI FFR. Adding the relative increase of FFR to post-PCI FFR would enable better discrimination of high-risk patients after stent implantation. (Influence of FFR on the Clinical Outcome After Percutaneous Coronary Intervention [PERSPECTIVE]; NCT01873560) (c) 2018 by the American College of Cardiology Foundation.