Trans-Stent FFR Gradient as a Modifiable Integrant in Predicting Long-Term Target Vessel Failure

Background: Fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) is associated with long-term outcomes. Data relating FFR-based trans-stent gradient (TSG) after PCI to long-term outcomes are sparse.

Objectives: The aim of this study was to test whether TSG is associated with adverse events at follow-up after PCI.

Methods: Data were gathered from a prospective registry evaluating 501 vessels in 416 patients with median follow-up period of 596 days. Primary endpoints were: 1) target vessel failure (TVF), including target vessel revascularization, and target vessel myocardial infarction after discharge; and 2) major adverse cardiac events (MACE) including TVF, target vessel revascularization, nontarget vessel MI, cardiac death.

Results: After PCI, median post-PCI FFR was 0.86 and median TSG was 0.04. TSG >0.04 was associated with increased rates of TVF (8.7% vs 2.9%; P = 0.014) and MACE (17.8% vs 9.2%; P = 0.02). Post-PCI FFR < 0.86 was associated with increased rates of TVF (6.1% vs 2.2%; P = 0.03) and MACE (16.5% vs 10%; P = 0.036). The vessel subgroup with high TSG and low FFR had significantly higher rates of TVF (10.2%; P = 0.02) and MACE (20.1%; P = 0.049) than vessels with: 1) high TSG and high FFR (TVF, 2.9%; MACE, 9.7%); 2) low TSG and low FFR (TVF, 3.8%; MACE, 11.3%); and 3) low TSG high FFR (TVF, 2.2%; MACE, 7.5%). In multivariate analysis, TSG was independently predictive of TVF.

Conclusions: Higher TSG was an independent predictor of adverse events, particularly TVF, and identified a subgroup of patients at higher risk for poor outcomes. The combination of high TSG and low FFR showed significantly worse outcomes compared with an "ideal result" (high FFR and low TSG). These data support a recommendation to use TSG during FFR evaluation to determine the functional success of PCI.