Combined Pressure and Flow Measurements to Guide Treatment of Coronary Stenoses

The aim of this study was to assess clinical outcomes after combined pressure and flow assessment of coronary lesions.

Although fractional flow reserve (FFR) remains the invasive reference standard for revascularization, approximately 40% of stenoses have discordant coronary flow reserve (CFR). Optimal treatment for these disagreements remains unclear.

A total of 455 subjects with 668 lesions were enrolled from 12 sites in 6 countries. Only lesions with reduced FFR and CFR underwent revascularization; all other combinations received initial medical therapy.

Fourteen percent of lesions had FFR ≤0.8 but CFR ≥2.0 while 23% of lesions had FFR >0.8 but CFR <2.0. During 2-year follow-up, the primary endpoint of composite all-cause death, myocardial infarction, and revascularization in lesions with FFR ≤0.8 but CFR ≥2.0 (10.8% event rate) compared with lesions with FFR >0.8 and CFR ≥2.0 (6.2% event rate) exceeded the prespecified +10% noninferiority margin (P = 0.090). Target vessel failure models using both continuous FFR and continuous CFR found that only higher FFR was associated with reduced target vessel failure (Cox P = 0.007) after initial medical treatment. Central core laboratory review accepted 69.8% of all tracings with mean differences of <0.01 for FFR and <0.02 for CFR, indicating no material impact on clinical measurements or outcomes.

All-cause death, myocardial infarction, and revascularization after 2 years was not noninferior between lesions with FFR ≤0.8 but CFR ≥2.0 and lesions with FFR >0.8 and CFR ≥2.0. These results do not support using invasive CFR ≥2.0 to defer revascularization for lesions with reduced FFR if the patient would otherwise be a candidate on the basis of the entire clinical scenario and treatment preference.