Usefulness of the trans-stent fractional flow reserve gradient for predicting clinical outcomes

Abstract

Objectives: We evaluated the usefulness of a fractional flow reserve (FFR) gradient across the stent (ΔFFRstent) for long-term clinical outcomes after percutaneous coronary intervention (PCI) with a drug-eluting stent (DES). Background: The clinical meaning of a trans-stent pressure gradient after DES implantation has not been estimated adequately. Methods: FFR pull-back and intravascular ultrasound (IVUS) were performed after successful PCI in 135 left anterior descending artery lesions. ΔFFRstent was defined as the FFR gradient across the stent. The ΔFFRstent/length was defined as the ΔFFRstent value divided by the total stent length multiplied by 10. Major adverse cardiac events (MACEs) were the composite of all-cause death, target vessel-related myocardial infarction, and target lesion revascularization. Results: Despite successful PCI, ΔFFRstent > 0 was observed in 98.5% of cases. ΔFFRstent ≥ 0.04 and ΔFFRstent/length ≥ 0.009 predicted suboptimal stenting defined as final minimal stent area < 5.5 mm2. During 2,183 ± 898 days, the MACE-free survival rate was significantly lower in patients with ΔFFRstent ≥ 0.04 and ΔFFRstent/length ≥ 0.009 compared to those with lower values (69.6 vs. 93.4%, log-rank p =.031; 72.1 vs. 97.7%, log-rank p =.003, respectively). ΔFFRstent/length ≥ 0.009 (hazard ratio 10.1, p =.032) was an independent predictor of MACE. Conclusion: A trans-stent FFR gradient was frequently observed. ΔFFRstent and ΔFFRstent/length are related to long-term outcomes in DES-treated patients.