Determinants of functional significance of coronary bifurcation lesions and clinical outcomes after physiology-guided treatment

Objectives: To determine the rate of functionally significant (fractional flow reserve, FFR < 0.80) coronary bifurcation stenoses that are considered anatomically significant based on angiographic estimation and to define predictors of functional significance of stenoses in main vessel and side branch. Background: To date, the rate of functionally significant stenoses in angiographic significant coronary bifurcation stenoses has not been specifically determined. Methods: Patients with significant angiographic bifurcation lesions defined as diameter stenosis >50% in main vessel and/or side branch were included. FFR was performed in main vessel (MV) and side branch (SB) before and after percutaneous coronary intervention (PCI). The protocol was approved by the local ethics committee. Results: Overall, 171 patients with bifurcation lesions were included. Mean FFR in MV was 0.80 +/- 0.01 and 0.84 +/- 0.09 in SB. 46% (n = 78) of bifurcation lesions were functionally significant when assessed with FFR. Diameter stenosis in main vessel, lesion length, side branch territory and SYNTAX score (SS) were found as predictors for lesion functional severity (main vessel FFR < 0.80). At the time of follow-up, there were no differences between the treated and deferred group regarding rates of all-cause death, cardio-vascular death, MACEs and POCE. Conclusion: Less than half of all angiographic significant bifurcation lesions were functionally significant when assessed with FFR. There was no difference in clinical outcomes at mean time of three years follow-up in treated and deferred lesion.