Predictors of successful post-PCI optimization in vessels with post-PCI fractional flow reserve <0.90: findings from the FFR REACT trial

Abstract Introduction Recent studies demonstrated a strong relation between suboptimal post-PCI fractional flow reserve (FFR) and clinical outcome. The feasibility of post-PCI FFR optimization and its impact on future clinical outcome remains topic of debate. Purpose The aim of the present substudy of the FFR REACT trial was to identify predictors of 1) absolute FFR increase following optimization and 2) successful functional optimization (final FFR ≥0.90). Methods The FFR REACT trial was a single-center, investigator initiated, randomized controlled trial including patients with (un)stable angina or non-ST segment elevation myocardial infarction and angiographically successful PCI. Following a post-PCI FFR <0.90, patients were randomized to intravascular ultrasound (IVUS)-guided optimization according to a dedicated optimization protocol (intervention arm) or no further treatment (control arm). In case of PCI optimization, FFR and IVUS were repeated to evaluate the optimization result. The present analysis included all patients randomized to IVUS-guided optimization, who actually underwent PCI optimization, and who had pre- and post-optimization FFR values available. We performed multivariate linear and logistic regression models to identify predictors of absolute FFR increase and FFR ≥0.90 following optimization. Results A total of 145 patients were allocated to the IVUS-guided optimization arm with 152 vessels having a post-PCI FFR <0.90 (mean post-PCI FFR: 0.83±0.05), of which 104 vessels (68.4%) underwent additional treatment after IVUS evaluation. Paired FFR measurements (pre- and post-optimization) were available in 100/104 optimized vessels. The mean absolute change in FFR was 0.03±0.06 (p<0.001), and 20/100 (20%) vessels achieved a final FFR ≥0.90. Both left anterior descending arteries (LAD) (mean change = -0.033, 95%CI -0.055- -0.010, p=0.004) and higher post-PCI FFR values (mean change per 0.01 unit increase = -0.005, 95%CI -0.007 - -0.004, p<0.001) were associated with lower changes in FFR following optimization. Independent predictors of achieving a final FFR ≥0.90 were higher post-PCI FFR values (OR 1.26 per 0.01 unit increase, 95%CI 1.06-1.51, p=0.009) and non-LAD vessels (OR 5.72, 95%CI 1.73-18.94, p=0.004). Conclusions Within the FFR REACT trial, we observed that the likelihood of improvement in final FFR values was driven by the initial post-PCI FFR values (before optimization) and the location of the target vessel, with non-LAD lesion location being a significant predictor of FFR increase.