Association of the severity of vascular damage with discordance between the fractional flow reserve and non-hyperemic pressure ratios

Background: While there is a discordance between fractional flow reserve (FFR) and non-hyperemic pressure ratios (NHPRs) in some cases, the mechanisms underlying these discordances have not yet been fully clarified. We examined whether vascular damage as assessed by measurement of the brachial-ankle pulse wave velocity (baPWV), a marker of arterial stiffness, or ankle brachial pressure index (ABI), a marker of atherosclerotic arterial stenosis, might be associated with their discordances.Methods: FFR and NHPRs were measured in 283 consecutive patients (69 +/- 10 years old). Based on previously established cut-off values of the two markers (i.e. +/- = FFR <=/> 0.80 or =NHPRs <=/> 0.89), the study participants were divided into four groups (the + and - signs denoting "predictive of significant stenosis" and "not predictive of significant stenosis," respectively): the FFR+/NHPRs+ group (n = 124), FFR-/NHPRs+ group (n = 16), FFR+/NHPRs- group(n = 65), and FFR-/NHPRs- group (n = 78). The baPWV and ABI were also measured in all the participants, and values of <2000 cm/s and >= 1.00 of the baPWV and ABI, respectively, were considered as representing relatively less advanced atherosclerotic systemic vascular damage. Results: The prevalence of subjects with ABI >= 1.00 was higher in the FFR+/NHPRs- group than in the FFR-/NHPRsgroup (p < 0.05). When the study subjects were divided into 2 groups, namely, the FFR+/NHPRs- group and the combined group, the prevalence of ABI >= 1.00 and that of baPWV <2000 cm/s were higher in the FFR+/NHPRsgroup as compared with those in the combined group (p < 0.05). The results of binary logistic regression analysis demonstrated that ABI >= 1.00 was associated with a significant odds ratio (2.34, p < 0.05) for the FFR+/NHPRsdiscordance.Conclusion: The FFR+/NHPRs- discordance appears to be observed in patients with relatively less advanced atherosclerotic systemic vascular damage. Thus, ABI >= 1.00 may be a marker of the presence of the FFR+/ NHPRs- discordance.