Background:
Many studies have demonstrated that deferral of percutaneous coronary intervention (PCI) on the basis of a myocardial fractional flow reserve (FFR) ≥0.75 is associated with a very low coronary event rate. However, some groups have empirically chosen the cut-off value of 0.80 rather than 0.75 for decision to defer PCI and the FFR measurement between 0.75 and 0.80 has been established as a grey zone. The aim of this study was to evaluate the long-term clinical outcomes of patients with moderate coronary lesions and FFR measurements between 0.75 and 0.80.
Methods:
The study included 125 anigiographically moderate coronary lesions (>50% diameter stenosis by visual assessment) in 125 patients but in whom the PCI was deferred on the basis of an FFR ≥ 0.75. The FFR was calculated as the ratio of mean distal pressure divided by the proximal pressure during hyperemia. Patients were divided into two groups according to the result of FFR: ≥ 0.80 (n=99, group 1) and between 0.75 and 0.79 (n=26, group 2). We evaluated the long-term major adverse cardiovascular events (MACE) related and unrelated to the FFR-evaluated lesion.
Results:
During a follow-up period of 82 ± 29 months (mean ± SD), The Kaplan-Meier event-free survival curves showed that group 2 was poorer than group 1 in prognosis (p=0.0148). The incidence of MACE unrelated FFR-evaluated lesion in group 1 was equivalent to that in group 2 (p=0.96).
Conclusions:
In patients with moderate coronary lesions and borderline FFR measurements, deferral of PCI was associated with a higher rate of MACE related to the FFR-evaluated lesion. FFR cut-off point of 0.80 instead of 0.75 may be more appropriate for deferring PCI.
Association of microvascular dysfunction with clinical outcomes in patients with non-flow limiting fractional flow reserve after percutaneous coronary intervention
