Fractional Flow Reserve in Acute Coronary Syndrome: An Updated Systematic Review and Bayesian Meta-Analysis.

BACKGROUND: The diagnostic performance of fractional flow reserve (FFR) in the setting of acute coronary syndrome (ACS) remains unclear. We sought to perform an updated systematic review and meta-analysis investigating the performance of FFR-guided revascularization in the setting of ACS. METHODS: Two main primary comparisons tested the major adverse cardiac events (MACE) rate at 1-year of patients treated with an FFR-guided strategy in ACS versus chronic coronary syndrome and an FFR-guided versus angiographic-guided strategy in acute coronary syndrome. Treatment effect was defined as the risk difference and was estimated with Bayesian random effect model with a conservative prior of no treatment effect. Kaplan-Meier estimates and their standard deviations were retrieved to maximum accuracy from cumulative incidence function/ survival function plots for studies with censoring. RESULTS: We found 11 eligible trials (with a total of 13 029 patients) in this systematic review. Within the FFR-guided strategy, acute coronary syndrome was associated with an increased risk of MACE at 1 year compared with chronic coronary syndrome (risk difference (RD): 1.9%, 95% credible interval [0.2% to 3.6%]). In contrast, among patients with ACS no difference in 1-year MACE rate was observed between angiography-guided versus FFR-guided complete revascularization strategy (RD=0.9%, 95% CI [-1.3 to 3.2]). CONCLUSIONS: FFR-guided strategy of lesions in acute coronary syndrome was associated with worse 1-year MACE compared with FFR-guided revascularization in chronic coronary syndrome reflecting the high-risk nature of acute coronary syndrome patients. No difference in long-term outcomes was seen from a FFR-guided versus angiography-guided approach in acute coronary syndrome. Further studies are needed to better understand and optimize the use of physiology in the ACS setting.