Coronary lesion progression as assessed by fractional flow reserve (FFR) and angiography.

AIMS: To explore the evolution of coronary lesions that had repeated physiologic evaluation by FFR as an endpoint, describe the clinical significance of longitudinal FFR change (ΔFFR = FFR follow-up - FFR baseline), its correlation with angiographic indices and identify predictors of FFR follow-up.

METHODS AND RESULTS: A retrospective, single-center analysis of 414 stenoses (331 patients) with consecutive FFR measurements at least six months apart was performed [median time interval: 24 (17, 37) months]. The change in percent diameter stenosis was 2% (-5%, 11%). FFR values at baseline and follow-up were 0.86 (0.82, 0.90) and 0.83 (0.79, 0.90) respectively (<0.0001). The median ΔFFR was -0.007 (-0.028, 0.010) per year. Worsening FFR (ΔFFR <-0.05) was observed in 105 (25%) stenoses, stable FFR (-0.05≤ΔFFR≤0.05) in 276 (67%) and improving FFR (ΔFFR>0.05) in 33 (8%) stenoses. The number of hemodynamically significant stenoses (FFR≤0.80) was higher at follow-up compared to baseline (33% versus 17%, P<0.0001); ΔFFR correlated weakly with delta diameter stenosis (Δ%DS, ρ=-0.111, P=0.024). FFR baseline and PCI between measurements at a non-index segment were independent predictors of FFR follow-up (R2=0.2301). In ROC analysis, FFR baseline values predicted future clinically significant values [c-statistic: 0.736 (95% CI: 0.682 - 0.783)].

CONCLUSIONS: FFR values decrease slowly over a two-year follow-up. FFR baseline, but not angiographic indices, is a predictor of significant functional atherosclerosis progression, predicting which stenoses will require revascularization.