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Background: Landmark trials showed that invasive pressure measurement (Fractional Flow Reserve, FFR) was a better guide to coronary stenting than visual assessment. However, present-day interventionists have benefited from extensive research and personal experience of mapping anatomy to hemodynamics., Aims: To determine if visual assessment of the angiogram performs as well as invasive measurement of coronary physiology., Methods: 25 interventional cardiologists independently visually assessed the single vessel coronary disease of 200 randomized participants in The Objective Randomized Blinded Investigation with optimal medical Therapy of Angioplasty in stable angina trial (ORBITA). They gave a visual prediction of the FFR and Instantaneous Wave-free Ratio (iFR), denoted vFFR and viFR respectively. Each judged each lesion on 2 occasions, so that every lesion had 50 vFFR, and 50 viFR assessments. The group consensus visual estimates (vFFR-group and viFR-group) and individual cardiologists' visual estimates (vFFR-individual and viFR-individual) were tested alongside invasively measured FFR and iFR for their ability to predict the placebo-controlled reduction in stress echo ischemia with stenting., Results: Placebo-controlled ischemia improvement with stenting was predicted by vFFR-group (p < 0.0001) and viFR-group (p < 0.0001), vFFR-individual (p < 0.0001) and viFR-individual (p < 0.0001). There were no significant differences between the predictive performance of the group visual estimates and their invasive counterparts: p = 0.53 for vFFR vs FFR and p = 0.56 for viFR vs iFR., Conclusion: Visual assessment of the angiogram by contemporary experts, provides significant additional information on the amount of ischaemia which can be relieved by placebo-controlled stenting in single vessel coronary artery disease., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Rasha Al-Lamee reports a relationship with A Menarini International Pharmaceutics that includes: speaking and lecture fees. Michael Foley reports a relationship with A Menarini International Pharmaceutics that includes: speaking and lecture fees. Christopher Rajkumar reports a relationship with A Menarini International Pharmaceutics that includes: speaking and lecture fees. Rasha Al-Lamee reports a relationship with Philips Healthcare that includes: speaking and lecture fees. Michael Foley reports a relationship with Philips Healthcare that includes: speaking and lecture fees. Christopher Rajkumar reports a relationship with Philips Healthcare that includes: speaking and lecture fees. Sayan Sen reports a relationship with Philips Healthcare that includes: speaking and lecture fees. Ricardo Petraco reports a relationship with Philips Healthcare that includes: speaking and lecture fees. Sukhjinder Nijjer reports a relationship with Philips Healthcare that includes: speaking and lecture fees. Takayuki Warisawa reports a relationship with Abbott Vascular Japan Co Ltd. that includes: consulting or advisory. Takayuki Warisawa reports a relationship with Philips Healthcare that includes:. Hitoshi Matsuo reports a relationship with Philips Healthcare that includes: speaking and lecture fees. Hitoshi Matsuo reports a relationship with Abbott Vascular Japan Co Ltd. that includes: speaking and lecture fees. Hitoshi Matsuo reports a relationship with Boston Scientific Japan that includes: speaking and lecture fees. Hitoshi Matsuo reports a relationship with Zeon Medical that includes: speaking and lecture fees. Shingo Kuwata reports a relationship with Abbott Vascular Japan Co Ltd. that includes: consulting or advisory., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

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-/NHPRs- group (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+/NHPRs- group 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+/NHPRs- discordance., 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., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: Determining the functional significance of each individual coronary lesion in patients with serial coronary stenoses is challenging. It has been proposed that nonhyperemic pressure ratios, such as the instantaneous wave free ratio (iFR) and the ratio of resting distal to proximal coronary pressure (Pd/Pa) are more accurate than fractional flow reserve (FFR) because autoregulation should maintain stable resting coronary flow and avoid hemodynamic interdependence (cross-talk) that occurs during hyperemia. This study aimed to measure the degree of hemodynamic interdependence of iFR, resting Pd/Pa, and FFR in a porcine model of serial coronary stenosis., Methods: In 6 anesthetized female swine, 381 serial coronary stenoses were created in the left anterior descending artery using 2 balloon catheters. The degree of hemodynamic interdependence was calculated by measuring the absolute changes in iFR, resting Pd/Pa, and FFR across the fixed stenosis as the severity of the other stenosis varied., Results: The hemodynamic interdependence of iFR, resting Pd/Pa, and FFR was 0.039±0.048, 0.021±0.026, and 0.034±0.034, respectively (all P <0.001). When the functional significance of serial stenoses was less severe (0.70-0.90 for each index), the hemodynamic interdependence was 0.009±0.020, 0.007±0.013, and 0.017±0.022 for iFR, resting Pd/Pa, and FFR, respectively (all P <0.001). However, in more severe serial coronary stenoses (<0.60 for each index), hemodynamic interdependence was 0.060±0.050, 0.037±0.030, and 0.051±0.037 for iFR, resting Pd/Pa, and FFR, respectively (all P <0.001)., Conclusions: When assessing serial coronary stenoses, nonhyperemic pressure ratios are affected by hemodynamic interdependence. When the functional significance of serial coronary stenoses is severe, the effect is similar to that which is seen with FFR.

Currently there is lack of data regarding the use of optical coherence tomography (OCT) to depict the hemodynamic relevance of coronary stenoses in diabetic patients. We sought to assess the diagnostic accuracy of OCT-derived morphologic assessment in identifying hemodynamically significant coronary lesions as determined by both, the resting instantaneous wave-free ratio (iFR) and the hyperemic fractional flow reserve (FFR) in diabetic patients. Diabetic patients presenting with at least one intermediate coronary lesion were prospectively and consecutively enrolled. All lesions were systematically assessed by iFR, FFR and OCT. A total of 41 intermediate lesions were analysed. Mean iFR and FFR values were 0.90 ± 0.04 and 0.81 ± 0.06, respectively (intra-class correlation coefficient 0.49; 95% CI 0.22-0.79). A moderate correlation between iFR and OCT derived minimal lumen diameter (MLD, r = 0.49) and minimal lumen area (MLA, r = 0.50) was found. Conversely, there was a poor correlation between FFR and OCT-derived MLD (r = 0.34) and MLA (r = 0.32). The diagnostic efficiency of MLA and MLD to identify iFR significant stenoses showed an AUC of 0.82 (95% CI 0.69-0.95) for MLD and 0.83 (95% CI 0.71-0.96) for MLA. A worse diagnostic efficiency was found when FFR was used as the reference with an AUC of 0.71 (95% CI 0.54-0.87) for MLD and 0.70 (95% CI 0.53-0.87). OCT-derived MLA and MLD were the strongest independent anatomic predictors of abnormal iFR and FFR values. In diabetic patients, OCT-derived MLA and MLD showed a moderate diagnostic efficiency in identifying functionally significant coronary stenoses by FFR or iFR. In diabetics, anatomic OCT measurements better predicted resting than FFR-determined physiologically significant lesions.

Objectives: The authors investigated 2-year clinical outcomes according to fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) values in deferred lesions., Background: Invasive physiological indices such as FFR or iFR are used in clinical practice to select ischemia-causing stenosis and to guide the treatment strategy for patients with coronary artery disease., Methods: From the 3V FFR-FRIENDS (3-Vessel Fractional Flow Reserve for the Assessment of Total Stenosis Burden and Its Clinical Impact in Patients With Coronary Artery Disease) study, 821 deferred lesions (n = 374) with both FFR and iFR available were included in this study. The primary outcome was major adverse cardiac events (MACE) (a composite of cardiac death, myocardial infarction, and ischemia-driven revascularization) at 2 years. The lesions were classified according to FFR and iFR cutpoints into concordant normal (Group 1: FFR >0.80 and iFR >0.89), high FFR and low iFR (Group 2: FFR >0.80 and iFR ≤0.89), low FFR and high iFR (Group 3: FFR ≤0.80 and iFR >0.89), and concordant abnormal (Group 4: FFR ≤0.80 and iFR ≤0.89)., Results: Deferred lesions with low FFR (≤0.80) or low iFR (≤0.89) showed significantly higher rates of 2-year MACE, compared with high FFR (>0.80) or high iFR (>0.89), respectively (7.2% in low FFR vs. 2.4% in high FFR; p < 0.001; 8.1% in low iFR vs. 2.4% in high iFR; p < 0.001). Both FFR and iFR showed significant association with occurrence of MACE as continuous values (hazard ratio [HR] of FFR: 0.570, 95% confidence interval [CI]: 0.337 to 0.963; p < 0.001; HR of iFR: 0.350, 95% CI: 0.217 to 0.567; p < 0.001). When comparing the discriminant ability between FFR and iFR, the c-index was comparable between FFR and iFR (c-index 0.677 vs. 0.685; p = 0.857). Among 4 groups classified according to FFR and iFR levels, only Group 4 with concordant abnormal results showed significantly higher risk of MACE, compared with group 1 (HR: 7.708, 95% CI: 2.621 to 22.667; p < 0.001)., Conclusions: Both FFR and iFR showed significant association with future risk of MACE in deferred lesions. The discordant results between FFR and iFR were not associated with the increased risk of MACE. The risk of MACE was significantly increased only in lesions with abnormal results of both FFR and iFR., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Although invasive physiological assessment for coronary stenosis has become a standard practice to guide treatment strategy, coronary circulatory response and changes in invasive physiological indexes, according to different anatomic and hemodynamic lesion severity, have not been fully demonstrated in patients with coronary artery disease., Methods: One hundred fifteen patients with left anterior descending artery stenosis who underwent both 13 N-ammonia positron emission tomography and invasive physiological measurement were analyzed. Myocardial blood flow (MBF) measured with positron emission tomography and invasively measured coronary pressures were used to calculate microvascular resistance and stenosis resistance., Results: With progressive worsening of angiographic stenosis severity, both resting and hyperemic transstenotic pressure gradient and stenosis resistance increased ( P <0.001 for all) and hyperemic MBF ( P <0.001) and resting microvascular resistance ( P =0.012) decreased. Resting MBF ( P =0.383) and hyperemic microvascular resistance ( P =0.431) were not changed and maintained stable. Both fractional flow reserve and instantaneous wave-free ratio decreased as angiographic stenosis severity, stenosis resistance, and transstenotic pressure gradient increased and hyperemic MBF decreased (all P <0.001). When the presence of myocardial ischemia was defined by both low hyperemic MBF and low coronary flow reserve, the diagnostic accuracy of fractional flow reserve and instantaneous wave-free ratio did not differ, regardless of cutoff values of hyperemic MBF and coronary flow reserve., Conclusions: This study demonstrated how the coronary circulation changes in response to increasing coronary stenosis severity using 13 N-ammonium positron emission tomography-derived MBF and invasively measured pressure data. Currently used resting and hyperemic pressure-derived invasive physiological indexes have similar patterns of relationships to the different anatomic and hemodynamic lesion severities., Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01366404., (© 2017 American Heart Association, Inc.)

Background: The invasive physiologic index such as fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR) is used in clinical practice to identify ischemia-causing stenosis and to guide treatment strategy. We investigated clinical and angiographic characteristics of lesions with discrepancy between FFR and iFR., Methods: From the 3V FFR-FRIENDS study, 975 vessels (393 patients) with available pre-intervention FFR and iFR were included in this study. The vessels were classified according to FFR and iFR into: concordant normal (Group 1 [n=724]: FFR>0.80 and iFR≥0.90); high FFR and low iFR (Group 2 [n=33]: FFR>0.80 and iFR<0.90); low FFR and high iFR (Group 3 [n=82]: FFR≤0.80 and iFR≥0.90); and concordant abnormal (Group 4 [n=136]: FFR≤0.80 and iFR<0.90)., Results: Angiographic stenosis severity assessed by percent diameter stenosis, minimum lumen diameter and lesion length was increased from Group 1 to Group 4 (all p<0.001). SYNTAX score increased and FFR decreased proportionally from Group 1 to Group 4 (all p<0.001). In multivariable GEE model, female, diabetes mellitus, smaller reference vessel diameter, and higher %DS were significantly associated with low iFR among high FFR groups (Group 2 discordance). Conversely, males, absence of diabetes mellitus and lower %DS were significantly associated with high iFR among low FFR groups (Group 3 discordance)., Conclusions: Four groups classified according to FFR and iFR were different in clinical and angiographic characteristics, SYNTAX score, and predictors of discordance. The lesions with discordant FFR and iFR may need to be interpreted as a different clinical entity., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Physiologic assessment using fractional flow reserve (FFR) to guide percutaneous coronary interventions (PCI) has been demonstrated to improve clinical outcomes, compared to angiography-guided PCI. Recently, resting indices such as resting Pd/Pa, "instantaneous wave-free ratio", and contrast medium induced FFR have been evaluated for the assessment of the functional consequences of coronary lesions. Herein, we review and discuss the use of FFR and other indices for the functional assessment of coronary lesions. This review will cover theoretical aspects, as well as practical points and common pitfalls related to coronary physiological assessment. © 2017 Wiley Periodicals, Inc., (© 2017 Wiley Periodicals, Inc.)