Impact of sex on the assessment of the microvascular resistance reserve.

BACKGROUND: The microvascular resistance reserve (MRR) is an innovative index to assess the vasodilatory capacity of the coronary circulation while accounting for the presence of concomitant epicardial disease. The MRR has shown to be a valuable diagnostic and prognostic tool in the general coronary artery disease (CAD) population. However, considering the fundamental aspects of its assessment and the unique hemodynamic characteristics of women, it is crucial to provide additional considerations for evaluating the MRR specifically in women. AIM: The aim of this study was to assess the diagnostic and prognostic applicability of the MRR in women and assess the potential differences across different sexes. METHODS: From the ILIAS Registry, we enrolled all patients with a stable indication for invasive coronary angiography, ensuring complete physiological and follow-up data. We analyzed the diagnostic value by comparing differences between sexes and evaluated the prognostic value of the MRR specifically in women, comparing it to that in men. RESULTS: A total of 1494 patients were included of which 26% were women. The correlation between MRR and CFR was good and similar between women (r = 0.80, p < 0.005) and men (r = 0.81, p < 0.005). The MRR was an independent and important predictor of MACE in both women (HR 0.67, 0.47-0.96, p = 0.027) and men (HR 0.84, 0.74-0.95, p = 0.007). The optimal cut-off value for MRR in women was 2.8 and 3.2 in men. An abnormal MRR similarly predicted MACE at 5-year follow-up in both women and men. CONCLUSION: The MRR seems to be equally applicable in both women and men with stable coronary artery disease.

Cost-Effectiveness of Fractional Flow Reserve-Guided Treatment for Acute Myocardial Infarction and Multivessel Disease: A Prespecified Analysis of the FRAME-AMI Randomized Clinical Trial.

Importance: Complete revascularization by non-infarct-related artery (IRA) percutaneous coronary intervention (PCI) in patients with acute myocardial infarction is standard practice to improve patient prognosis. However, it is unclear whether a fractional flow reserve (FFR)-guided or angiography-guided treatment strategy for non-IRA PCI would be more cost-effective. Objective: To evaluate the cost-effectiveness of FFR-guided compared with angiography-guided PCI in patients with acute myocardial infarction and multivessel disease. Design, Setting, and Participants: In this prespecified cost-effectiveness analysis of the FRAME-AMI randomized clinical trial, patients were randomly allocated to either FFR-guided or angiography-guided PCI for non-IRA lesions between August 19, 2016, and December 24, 2020. Patients were aged 19 years or older, had ST-segment elevation myocardial infarction (STEMI) or non-STEMI and underwent successful primary or urgent PCI, and had at least 1 non-IRA lesion (diameter stenosis >50% in a major epicardial coronary artery or major side branch with a vessel diameter of ≥2.0 mm). Data analysis was performed on August 27, 2023. Intervention: Fractional flow reserve-guided vs angiography-guided PCI for non-IRA lesions. Main Outcomes and Measures: The model simulated death, myocardial infarction, and repeat revascularization. Future medical costs and benefits were discounted by 4.5% per year. The main outcomes were quality-adjusted life-years (QALYs), direct medical costs, incremental cost-effectiveness ratio (ICER), and incremental net monetary benefit (INB) of FFR-guided PCI compared with angiography-guided PCI. State-transition Markov models were applied to the Korean, US, and European health care systems using medical cost (presented in US dollars), utilities data, and transition probabilities from meta-analysis of previous trials. Results: The FRAME-AMI trial randomized 562 patients, with a mean (SD) age of 63.3 (11.4) years. Most patients were men (474 [84.3%]). Fractional flow reserve-guided PCI increased QALYs by 0.06 compared with angiography-guided PCI. The total cumulative cost per patient was estimated as $1208 less for FFR-guided compared with angiography-guided PCI. The ICER was -$19 484 and the INB was $3378, indicating that FFR-guided PCI was more cost-effective for patients with acute myocardial infarction and multivessel disease. Probabilistic sensitivity analysis showed consistent results and the likelihood iteration of cost-effectiveness in FFR-guided PCI was 97%. When transition probabilities from the pairwise meta-analysis of the FLOWER-MI and FRAME-AMI trials were used, FFR-guided PCI was more cost-effective than angiography-guided PCI in the Korean, US, and European health care systems, with an INB of $3910, $8557, and $2210, respectively. In probabilistic sensitivity analysis, the likelihood iteration of cost-effectiveness with FFR-guided PCI was 85%, 82%, and 31% for the Korean, US, and European health care systems, respectively. Conclusions and Relevance: This cost-effectiveness analysis suggests that FFR-guided PCI for non-IRA lesions saved medical costs and increased quality of life better than angiography-guided PCI for patients with acute myocardial infarction and multivessel disease. Fractional flow reserve-guided PCI should be considered in determining the treatment strategy for non-IRA stenoses in these patients. Trial Registration: ClinicalTrials.gov Identifier: NCT02715518.

Practical Application of Coronary Physiologic Assessment: Asia-Pacific Expert Consensus Document: Part 2.

Coronary physiologic assessment is performed to measure coronary pressure, flow, and resistance or their surrogates to enable the selection of appropriate management strategy and its optimization for patients with coronary artery disease. The value of physiologic assessment is supported by a large body of clinical data that has led to major recommendations in all practice guidelines. This expert consensus document aims to convey practical and balanced recommendations and future perspectives for coronary physiologic assessment for physicians and patients in the Asia-Pacific region, based on updated information in the field that includes both wire- and image-based physiologic assessment. This is Part 2 of the whole consensus document, which provides theoretical and practical information on physiologic indexes for specific clinical conditions and patient statuses.

QFR Assessment and Prognosis After Nonculprit PCI in Patients With Acute Myocardial Infarction.

BACKGROUND: Complete revascularization using either angiography-guided or fractional flow reserve (FFR)-guided strategy can improve clinical outcomes in patients with acute myocardial infarction (AMI) and multivessel disease. However, there is concern that angiography-guided percutaneous coronary intervention (PCI) may result in un-necessary PCI of the non-infarct-related artery (non-IRA), and its long-term prognosis is still unclear. OBJECTIVES: This study sought to evaluate clinical outcomes after non-IRA PCI according to the quantitative flow ratio (QFR). METHODS: We performed post hoc QFR analysis of non-IRA lesions of AMI patients enrolled in the FRAME-AMI (FFR Versus Angiography-Guided Strategy for Management of AMI With Multivessel Disease) trial, which randomly allocated 562 patients into either FFR-guided PCI (FFR ≤0.80) or angiography-guided PCI (diameter stenosis >50%) for non-IRA lesions. Patients were classified by non-IRA QFR values into the QFR ≤0.80 and QFR >0.80 groups. The primary outcome was a major adverse cardiac event (MACE), a composite of cardiac death, myocardial infarction, and repeat revascularization. RESULTS: A total of 443 patients (552 lesions) were eligible for QFR analysis. Of 209 patients in the angiography-guided PCI group, 30.0% (n = 60) underwent non-IRA PCI despite having QFR >0.80 in the non-IRA. Conversely, only 2.7% (n = 4) among 209 patients in the FFR-guided PCI group had QFR >0.80 in the non-IRA. At a median follow-up of 3.5 years, the rate of MACEs was significantly higher among patients with non-IRA PCI despite QFR >0.80 than in patients with deferred PCI for non-IRA lesions (12.9% vs 3.1%; HR: 4.13; 95% CI: 1.10-15.57; P = 0.036). Non-IRA PCI despite QFR >0.80 was associated with a higher risk of non-IRA MACEs than patients with deferred PCI for non-IRA lesions (12.9% vs 2.1%; HR: 5.44; 95% CI: 1.13-26.19; P = 0.035). CONCLUSIONS: In AMI patients with multivessel disease, 30.0% of angiography-guided PCI resulted in un-necessary PCI for the non-IRA with QFR >0.80, which was significantly associated with an increased risk of MACEs than in those with deferred PCI for non-IRA lesions. (FFR Versus Angiography-Guided Strategy for Management of AMI With Multivessel Disease [FRAME-AMI] ClinicalTrials.gov number; NCT02715518).

Long-term prognostic implications of hemodynamic and plaque assessment using coronary CT angiography.

BACKGROUND AND AIMS: Hemodynamic and plaque characteristics can be analyzed using coronary CT angiography (CTA). We aimed to explore long-term prognostic implications of hemodynamic and plaque characteristics using coronary CT angiography (CTA). METHODS: Invasive fractional flow reserve (FFR) and CTA-derived FFR (FFRCT) were undertaken for 136 lesions in 78 vessels and followed-up to 10 years until December 2020. FFRCT, wall shear stress (WSS), change in FFRCT across the lesion (ΔFFRCT), total plaque volume (TPV), percent atheroma volume (PAV), and low-attenuation plaque volume (LAPV) for target lesions [L] and vessels [V] were obtained by independent core laboratories. Their collective influence was evaluated for the clinical endpoints of target vessel failure (TVF) and target lesion failure (TLF). RESULTS: During a median follow-up of 10.1 years, PAV[V] (per 10% increase, HR 2.32 [95% CI 1.11-4.86], p = 0.025), and FFRCT[V] (per 0.1 increase, HR 0.56 [95% CI 0.37-0.84], p = 0.006) were independent predictors of TVF for the per-vessel analysis, and WSS[L] (per 100 dyne/cm2 increase, HR 1.43 [1.09-1.88], p = 0.010), LAPV[L] (per 10 mm3 increase, HR 3.81 [1.16-12.5], p = 0.028), and ΔFFRCT[L] (per 0.1 increase, HR 1.39 [1.02-1.90], p = 0.040) were independent predictors of TLF for the per-lesion analysis after adjustment for clinical and lesion characteristics. The addition of both plaque and hemodynamic predictors improved the predictability for 10-year TVF and TLF of clinical and lesion characteristics (all p < 0.05). CONCLUSIONS: Vessel- and lesion-level hemodynamic characteristics, and vessel-level plaque quantity, and lesion-level plaque compositional characteristics assessed by CTA offer independent and additive long-term prognostic value.

Combined Assessment of FFR and CFR for Decision Making in Coronary Revascularization: From the Multicenter International ILIAS Registry.

OBJECTIVES: The aim of this study was to demonstrate the clinical implications of combined assessment of fractional flow reserve (FFR) and coronary flow reserve (CFR). BACKGROUND: Combined assessment of FFR and CFR allows detailed characterization of pathophysiology in chronic coronary syndromes. Data on the clinical implications of distinct FFR and CFR patterns are limited, leading to uncertainty regarding their relevance. METHODS: Patients with chronic coronary syndromes and obstructive coronary artery disease were selected from the multicenter ILIAS (Inclusive Invasive Physiological Assessment in Angina Syndromes) registry. Patients were classified into 4 groups on the basis of FFR ≤0.80 and CFR <2.0. The endpoint was the 5-year target vessel failure (TVF) rate. RESULTS: A total of 2,143 patients with 2,725 lesions were included. Compared with normal FFR/normal CFR, low FFR/low CFR carried the highest risk for TVF (HR: 5.4; 95% CI: 3.2-9.3; P < 0.001), significantly higher than in revascularized vessels (P = 0.007). Discordance, with either low FFR/normal CFR or normal FFR/low CFR, was associated with increased TVF rates compared with normal FFR/normal CFR (low FFR/normal CFR: HR: 3.5 [95% CI: 2.2-5.4; P < 0.001]; normal FFR/low CFR: HR: 3.0 [95% CI: 1.9-4.7; P < 0.001]). No difference in 5-year TVF was observed between the 2 discordant groups (P = 0.57) or between the discordant groups and the revascularized group (P = 0.26 vs low FFR/normal CFR; P = 0.60 vs normal FFR/low CFR). CONCLUSIONS: Impaired coronary hemodynamics are uniformly associated with increased 5-year TVF rates. Nonrevascularized vessels with discordant FFR and CFR are associated with 5-year event rates that are equivalent to those of vessels that undergo revascularization, whereas vessels with combined low FFR and CFR exhibit event rates that are significantly higher than after revascularization. (Inclusive Invasive Physiological Assessment in Angina Syndromes Registry [ILIAS Registry]; NCT04485234).

Association between patient age, microcirculation, and coronary stenosis assessment with fractional flow reserve and instantaneous wave-free ratio.

OBJECTIVES: To investigate the effect of aging on coronary stenosis functional assessment with fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR). BACKGROUND: Limited data exist regarding the impact of patient age on these coronary pressure indices. METHODS: We analyzed 514 patients with coronary stenosis interrogated with intravascular physiology. The influence of patient age on FFR, iFR, and microcirculation-related indices was investigated. Vessel-oriented composite outcome (VOCO) was assessed in the FFR-based deferred population according to iFR, coronary flow reserve (CFR), and age. RESULTS: FFR increased (r = 0.128, p = 0.004), iFR remained unchanged (r = -0.001, p = 0.980), and CFR decreased (r = -0.095, p = 0.001) with patient age. Relationship between FFR and CFR differed across age groups (r = 0.263 in <60 years old vs. r = 0.124 in ≥60 years old, p = 0.0056), whereas iFR correlated to CFR similarly regardless age (r = 0.283 in <60 years old vs. r = 0.219 in ≥60 years old, p = 0.3781). No differences were found on angiographic stenosis severity (%DS 47.4 in <60 years old and 49.8 in ≥60 years old, p = 0.317). At 5 years, FFR-based revascularisation deferral in patients ≥60 years old was associated with more VOCO when either iFR (25%) or CFR (16.9%) were abnormal, compared to patients with normal iFR (6.3%) or normal CFR (4.6%) (log-rank p < 0.001). This difference in clinical outcomes was not observed in younger patients. CONCLUSIONS: FFR values increased progressively with patient age, potentially associated with age-related changes in the coronary microcirculation. Conversely, iFR values remained unchanged across the patient age spectrum. In ≥60 years old patients with revascularisation deferral based on FFR, both abnormal iFR and CFR values were associated with worse long-term patient outcomes.

Long-term Patient Prognostication by Coronary Flow Reserve and Index of Microcirculatory Resistance: International Registry of Comprehensive Physiologic Assessment.

BACKGROUND AND OBJECTIVES: Recent guideline recommends evaluation using of coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) in patients with functionally insignificant stenosis. We evaluated clinical implications of CFR and IMR in patients with high fractional flow reserve (FFR) and deferred revascularization. METHODS: A total of 867 patients (1,152 vessels) consigned to deferred revascularization who underwent comprehensive physiologic assessments were enrolled. Patients with high FFR (>0.80) were categorized by CFR (≤2) and IMR (≥23 U). Clinical outcome was assessed by patient-oriented composite outcome (POCO), a composite of any death, myocardial infarction (MI), and revascularization at 5 years. RESULTS: Patients with low CFR (≤2) showed significantly greater risk of POCO than those with high CFR (>2) in both high-FFR (p=0.024) and low-FFR (p=0.034) groups. In patients with high FFR, those with low CFR and high IMR (overt microvascular disease) displayed the greatest risk of POCO overall (p=0.015), surpassing those with high CFR and low IMR (HR, 2.873; 95% CI, 1.476-5.594; p=0.002) and showing significantly greater risk of cardiac death or MI (HR, 5.662; 95% CI, 1.984-16.154; p=0.001). Overt microvascular disease was independently associated with POCO in the high-FFR population (HR, 2.282; 95% CI, 1.176-4.429; p=0.015). CONCLUSION: Among patients with deferred revascularization, those with low CFR showed significantly greater risk of POCO than those with high CFR, regardless of FFR. In patients with high FFR, those with overt microvascular disease showed significantly greater risk of POCO and cardiac death or MI at 5-year, compared with the others. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03690713.

Role of Post-Stent Physiological Assessment in a Risk Prediction Model After Coronary Stent Implantation.

OBJECTIVES: The aim of this study was to develop a risk model incorporating clinical, angiographic, and physiological parameters to predict future clinical events after drug-eluting stent implantation. BACKGROUND: Prognostic factors after coronary stenting have not been comprehensively investigated. METHODS: A risk model to predict target vessel failure (TVF) at 2 years was developed from 2,200 patients who underwent second-generation drug-eluting stent implantation and post-stent fractional flow reserve (FFR) measurement. TVF was defined as a composite of cardiac death, target vessel myocardial infarction, and clinically driven target vessel revascularization. A random survival forest model with automatic feature selection by minimal depth analysis was used for risk model development. RESULTS: During 2 years of follow-up, the cumulative incidence of TVF was 5.9%. From clinical, angiographic, and physiological parameters, 6 variables were selected for the risk model in order of importance within the model as follows: total stent length, post-stent FFR, age, post-stent percentage diameter stenosis, reference vessel diameter, and diabetes mellitus. Harrell's C index of the random survival forest model was 0.72 (95% confidence interval [CI]: 0.62 to 0.82). This risk model showed better prediction ability than models with clinical risk factors alone (Harrell's C index = 0.55; 95% CI: 0.41 to 0.59; p for comparison = 0.005) and with clinical risk factors and angiographic parameters (Harrell's C index = 0.65; 95% CI: 0.52 to 0.77; p for comparison = 0.045). When the patients were divided into 2 groups according to the median of total stent length (30 mm), post-stent FFR and total stent length showed the highest variable importance in the short- and long-stent groups, respectively. CONCLUSIONS: A risk model incorporating clinical, angiographic, and physiological predictors can help predict the risk for TVF at 2 years after coronary stenting. Total stent length and post-stent FFR were the most important predictors. (International Post PCI FFR Registry; NCT04012281).

Effect of Sex Difference of Coronary Microvascular Dysfunction on Long-Term Outcomes in Deferred Lesions.

OBJECTIVES: This study investigated the sex difference of long-term cardiovascular outcomes on coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) in patients with deferred coronary artery lesions. BACKGROUND: Coronary microvascular dysfunction is associated with poorer long-term outcomes. It can be assessed by CFR and the IMR. METHODS: The study prospectively enrolled 434 patients (133 women and 301 men) and analyzed CFR, IMR, fractional flow reserve, and quantitative coronary angiography. Clinical outcomes were assessed by major adverse cardiovascular event(s) (MACE) of cardiac death, myocardial infarction, and revascularization during 5 years of follow-up. The study protocol was approved by the Institutional Review Board or Ethics Committee at each participating center, and all patients provided written informed consent. The study protocol was in accordance with the Declaration of Helsinki. RESULTS: Women had milder epicardial disease compared with men (fractional flow reserve: 0.91 [interquartile range (IQR): 0.87 to 0.96] vs. 0.90 [IQR: 0.86 to 0.95]; p = 0.037). IMR was similar between the sexes, but CFR was lower in women (2.69 [IQR: 2.08 to 3.90] vs. 3.20 [IQR: 2.20 to 4.31]; p = 0.006) due to a shorter resting mean transit time, whereas hyperemic mean transit times were similar. At 5-year follow-up, MACE was significantly lower in women compared with men (1.1% vs. 5.5%; p = 0.017). Sex, diabetes mellitus, and CFR were independent predictors for MACE for all patients. The risk of MACE was significantly higher in men with low versus high CFR (hazard ratio: 4.58; 95% confidence interval: 1.85 to 11.30; p = 0.011) which was not seen in women. CONCLUSIONS: There was no sex difference in microvascular function by IMR. CFR was lower in women due to a higher resting coronary flow; however, long-term clinical outcomes in deferred lesions were better in women compared with men. (Clinical, Physiological and Prognostic Implication of Microvascular Status; NCT02186093).

Sex Differences in Long-Term Outcomes in Patients With Deferred Revascularization Following Fractional Flow Reserve Assessment: International Collaboration Registry of Comprehensive Physiologic Evaluation.

Background Sex-specific differences may influence prognosis after deferred revascularization following fractional flow reserve (FFR) measurement. This study sought to investigate the sex differences in long-term prognosis of patients with deferred revascularization following FFR assessment. Methods and Results A total of 879 patients (879 vessels) with deferred revascularization with FFR >0.75 who underwent FFR and coronary flow reserve measurements were enrolled from 3 countries (Korea, Japan, and Spain). Long-term outcomes were assessed in 649 men and 230 women by the patient-oriented composite outcome (POCO, a composite of any death, any myocardial infarction, and any revascularization). We applied inverse-probability weighting based on propensity scores to account for differences at baseline between women and men (age, hyperlipidemia, diabetes mellitus, diameter stenosis, lesion length, multivessel disease, FFR, coronary flow reserve. The median follow-up duration was 1855 days (745-1855 days). Median FFR values were 0.88 (0.83-0.93) in men and 0.89 (0.85-0.94) in women, respectively. The occurrences of POCO were significantly high in men compared with that in women (10.5% versus 4.2%, P=0.007). Kaplan-Meier analysis revealed that women had a significantly lower risk of POCO (χ2=7.2, P=0.007). Multivariate COX proportional hazards regression analysis revealed that age, male, diabetes mellitus, diameter stenosis, lesion length, and coronary flow reserve were independent predictors of POCO. After applying IPW, the hazard ratio of males for POCO was 2.07 (95% CI, 1.07-4.04, P=0.032). Conclusions This large multinational study reveals that long-term outcome differs between women and men in favor of women after FFR-guided revascularization deferral. Clinical Trial Registration URL: http://www.ClinicalTrials.gov. Unique identifier: NCT02186093.

Sex Differences in Instantaneous Wave-Free Ratio or Fractional Flow Reserve-Guided Revascularization Strategy.

OBJECTIVES: This study sought to evaluate sex differences in procedural characteristics and clinical outcomes of instantaneous wave-free ratio (iFR)- and fractional flow reserve (FFR)-guided revascularization strategies. BACKGROUND: An iFR-guided strategy has shown a lower revascularization rate than an FFR-guided strategy, without differences in clinical outcomes. METHODS: This is a post hoc analysis of the DEFINE-FLAIR (Functional Lesion Assessment of Intermediate stenosis to guide Revascularization) study, in which 601 women and 1,891 men were randomized to iFR- or FFR-guided strategy. The primary endpoint was 1-year major adverse cardiac events (MACE), a composite of all-cause death, nonfatal myocardial infarction, or unplanned revascularization. RESULTS: Among the entire population, women had a lower number of functionally significant lesions per patient (0.31 ± 0.51 vs. 0.43 ± 0.59; p < 0.001) and less frequently underwent revascularization than men (42.1% vs. 53.1%; p < 0.001). There was no difference in mean iFR value according to sex (0.91 ± 0.09 vs. 0.91 ± 0.10; p = 0.442). However, the mean FFR value was lower in men than in women (0.83 ± 0.09 vs. 0.85 ± 0.10; p = 0.001). In men, an FFR-guided strategy was associated with a higher rate of revascularization than an iFR-guided strategy (57.1% vs. 49.3%; p = 0.001), but this difference was not observed in women (41.4% vs. 42.6%; p = 0.757). There was no difference in MACE rates between iFR- and FFR-guided strategies in both women (5.4% vs. 5.6%, adjusted hazard ratio: 1.10; 95% confidence interval: 0.50 to 2.43; p = 0.805) and men (6.6% vs. 7.0%, adjusted hazard ratio: 0.98; 95% confidence interval: 0.66 to 1.46; p = 0.919). CONCLUSIONS: An FFR-guided strategy was associated with a higher rate of revascularization than iFR-guided strategy in men, but not in women. However, iFR- and FFR-guided strategies showed comparable clinical outcomes, regardless of sex. (Functional Lesion Assessment of Intermediate Stenosis to guide Revascularization [DEFINE-FLAIR]; NCT02053038).

Consensus document for invasive coronary physiologic assessment in Asia-Pacific countries.

BACKGROUND: Currently, invasive physiologic assessment such as fractional flow reserve is widely used worldwide with different adoption rates around the globe. Patient characteristics and physician preferences often differ in the Asia-Pacific (APAC) region with respect to treatment strategy, techniques, lesion complexity, access to coronary physiology and imaging devices, as well as patient management. Thus, there is a need to construct a consensus document on recommendations for use of physiology-guided percutaneous coronary intervention (PCI) in APAC populations. This document serves as an overview of recommendations describing the best practices for APAC populations to achieve more consistent and optimal clinical outcomes. METHODS AND RESULTS: A comprehensive multiple-choice questionnaire was provided to 20 interven- tional cardiologists from 10 countries in the APAC region. Clinical evidence, tips and techniques, and clinical situations for the use of physiology-guided PCI in APAC were reviewed and used to propose key recommendations. There are suggestions to continue to develop evidence for lesion and patient types that will benefit from physiology, develop directions for future research in health economics and local data, develop appropriate use criteria in different countries, and emphasize the importance of education of all stakeholders. A consensus recommendation to enhance the penetration of invasive physiology-based therapy was to adopt the 5E approach: Evidence, Education, Expand hardware, Economics and Expert consensus. CONCLUSIONS: This consensus document and recommendations support interventional fellows and cardiologists, hospital administrators, patients, and medical device companies to build confidence and encourage wider implementation of invasive coronary physiology-guided therapy in the APAC region.

Influence of Sex on Relationship Between Total Anatomical and Physiologic Disease Burdens and Their Prognostic Implications in Patients With Coronary Artery Disease.

Background Total atherosclerosis disease burden is associated with clinical outcomes in patients with coronary artery disease. However, the influence of sex on the relationship between total anatomical and physiologic disease burdens and their prognostic implications have not been well defined. Methods and Results A total of 1136 patients who underwent fractional flow reserve (FFR) measurement in all 3 major coronary arteries were included in this study. Anatomical and physiologic total disease burden was assessed by SYNTAX (Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery) score, residual SYNTAX score, a total sum of FFR in 3 vessels (3-vessel FFR), and functional SYNTAX score. The primary end point was major adverse cardiac events, a composite of cardiac death, myocardial infarction, and ischemia-driven revascularization at 2 years. There were no differences in angiographic diameter stenosis, SYNTAX score, or residual SYNTAX score between women and men. However, both per-vessel FFR (0.89±0.10 versus 0.87±0.11, P<0.001) and 3-vessel FFR (2.72±0.13 versus 2.69±0.15, P<0.001) were higher in women. Multivariable Cox regression analyses showed that total anatomical and physiologic disease burdens were significantly associated with 2-year major adverse cardiac events, and there was no significant interaction between sex and total disease burden for clinical outcomes. Conclusions Despite similar angiographic disease severity, both per-vessel and per-patient physiologic disease severity was less in women than in men. There was no influence of sex on prognostic implications of total anatomical and physiologic disease burdens in patients with coronary artery disease. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT01621438.

Clinical Events After Deferral of LAD Revascularization Following Physiological Coronary Assessment.

BACKGROUND: Physicians are not always comfortable deferring treatment of a stenosis in the left anterior descending (LAD) artery because of the perception that there is a high risk of major adverse cardiac events (MACE). The authors describe, using the DEFINE-FLAIR (Functional Lesion Assessment of Intermediate Stenosis to Guide Revascularisation) trial, MACE rates when LAD lesions are deferred, guided by physiological assessment using fractional flow reserve (FFR) or the instantaneous wave-free ratio (iFR). OBJECTIVES: The purpose of this study was to establish the safety of deferring treatment in the LAD using FFR or iFR within the DEFINE-FLAIR trial. METHODS: MACE rates at 1 year were compared between groups (iFR and FFR) in patients whose physiological assessment led to LAD lesions being deferred. MACE was defined as a composite of cardiovascular death, myocardial infarction (MI), and unplanned revascularization at 1 year. Patients, and staff performing follow-up, were blinded to whether the decision was made with FFR or iFR. Outcomes were adjusted for age and sex. RESULTS: A total of 872 patients had lesions deferred in the LAD (421 guided by FFR, 451 guided by iFR). The event rate with iFR was significantly lower than with FFR (2.44% vs. 5.26%; adjusted HR: 0.46; 95% confidence interval [CI]: 0.22 to 0.95; p = 0.04). This was driven by significantly lower unplanned revascularization with iFR and numerically lower MI (unplanned revascularization: 2.22% iFR vs. 4.99% FFR; adjusted HR: 0.44; 95% CI: 0.21 to 0.93; p = 0.03; MI: 0.44% iFR vs. 2.14% FFR; adjusted HR: 0.23; 95% CI: 0.05 to 1.07; p = 0.06). CONCLUSIONS: iFR-guided deferral appears to be safe for patients with LAD lesions. Patients in whom iFR-guided deferral was performed had statistically significantly lower event rates than those with FFR-guided deferral.

Physiological and Clinical Assessment of Resting Physiological Indexes.

BACKGROUND: Recently, resting pressure-derived indexes such as resting full-cycle ratio (RFR) and diastolic pressure ratio (dPR) have been introduced to assess the functional significance of epicardial coronary stenosis. The present study sought to investigate the agreement of RFR or dPR with other pressure-derived indexes (instantaneous wave-free ratio [iFR] or fractional flow reserve), the sensitivity of RFR or dPR for anatomic or hemodynamic stenosis severity, and the prognostic implications of RFR or dPR compared with iFR Methods: RFR and dPR were calculated from resting pressure tracings by an independent core laboratory in 1024 vessels (435 patients). The changes in resting physiological indexes according to diameter stenosis were compared among iFR, RFR, and dPR. Among 115 patients who underwent 13N-ammonia positron emission tomography, the changes in those indexes according to basal and hyperemic stenosis resistance and absolute hyperemic myocardial blood flow were compared. The association between resting physiological indexes and the risk of 2-year vessel-oriented composite outcomes (a composite of cardiac death, vessel-related myocardial infarction, and vessel-related ischemia-driven revascularization) was analyzed among 864 deferred vessels. RESULTS: Both RFR and dPR showed a significant correlation with iFR ( R=0.979, P<0.001 for RFR; and R=0.985, P<0.001 for dPR), which was higher than that with fractional flow reserve ( R=0.822, P<0.001; and R=0.819, P<0.001, respectively). RFR and dPR showed a very high agreement with iFR (C index, 0.987 and 0.993). Percent difference of iFR, RFR, and dPR according to the increase in anatomic and hemodynamic severity was almost identical. The diagnostic performance of iFR, RFR, and dPR was not different in the prediction of myocardial ischemia defined by both low hyperemic myocardial blood flow and low coronary flow reserve by 13N-ammonia positron emission tomography. All resting physiological indexes showed significant association with the risk of 2-year vessel-oriented composite outcomes (iFR per 0.1 increase: hazard ratio, 0.514 [95% CI, 0.370-0.715], P<0.001; RFR per 0.1 increase: hazard ratio, 0.524 [95% CI, 0.378-0.725], P<0.001; dPR per 0.1 increase: hazard ratio, 0.587 [95% CI, 0.436-0.791], P<0.001) in deferred vessels. CONCLUSIONS: All resting pressure-derived physiological indexes (iFR, RFR, and dPR) can be used as invasive tools to guide treatment strategy in patients with coronary artery disease. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT01621438.

Three-Vessel Assessment of Coronary Microvascular Dysfunction in Patients With Clinical Suspicion of Ischemia: Prospective Observational Study With the Index of Microcirculatory Resistance.

BACKGROUND: Difficulty directly visualizing the coronary microvasculature as opposed to the epicardial coronary artery makes its assessment challenging. The goal of this study is to measure the index of microcirculatory resistance (IMR) in all 3 major coronary vessels to identify the clinical and angiographic predictors of an abnormal IMR. METHODS AND RESULTS: Ninety-three patients who underwent coronary physiological assessment in all 3 major coronary vessels were prospectively enrolled (59.8±9.4 years with 77.4% men). IMR was corrected using Yong's formula and coronary microvascular dysfunction (CMD) was defined using vessel-specific cutoffs. A global IMR was calculated as the sum of the IMR in all 3 major epicardial vessels. Angiographic epicardial disease severity was assessed with vessel-specific and overall SYNTAX score. Median IMR and fractional flow reserve was 17.2 (Q1-Q3: 13.3-22.9) and 0.92 (0.85-0.97). The majority of patients (59.1%) had no CMD, 23.7% had 1-vessel CMD, 14.0% had 2-vessel CMD, and 3.2% had 3-vessel CMD. CMD was observed at a similar rate in the territories supplied by all 3 major coronary vessels (left anterior descending coronary artery 28.0%, left circumflex artery 19.4%, and right coronary artery 23.7%; P=0.39). Fractional flow reserve had a weak, positive correlation with IMR (ρ=0.16; P<0.01). The SYNTAX score had no significant correlation with IMR, both at a patient level (ρ=-0.002; P=0.99) and a vessel-specific level (ρ=-0.06; P=0.36). By multivariable ordinal logistic regression analysis, no variable was left as an independent predictor of an abnormal IMR. CONCLUSIONS: Clinical factors and epicardial coronary disease severity are not predictors of the extent of CMD. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01621438.

Safety and efficacy of intracoronary nicorandil as hyperaemic agent for invasive physiological assessment: a patient-level pooled analysis.

AIMS: Our aim was to evaluate the safety and efficacy of intracoronary (IC) nicorandil as an alternative choice of hyperaemic agent for invasive physiologic studies. METHODS AND RESULTS: A total of 480 intermediate coronary lesions from 429 patients enrolled from six Japanese and Korean centres were analysed. IC nicorandil showed earlier achievement of hyperaemia (time to the lowest FFR: 18.0 s [1st and 3rd quartile value 15.6-21.5] vs. 44.0 s [36.0-60.0], p<0.001) with similar hyperaemic efficacy, compared with intravenous (IV) adenosine/ATP (FFR 0.82 [0.75-0.87] vs. 0.82 [0.74-0.88], p=0.207). FFR measurements with both agents showed excellent correlation and classification agreement (CA) for FFR ≤0.80 (r=0.941, ICC 0.980, CA 90.8%, kappa=0.814, AUC of nicorandil 0.980, all p<0.001). Only three patients (0.7%) showed changes in classification across the grey zone (0.75-0.80). IC nicorandil produced fewer changes in blood pressure (BP) and heart rate (HR) and showed less chest pain than IV adenosine/ATP (all p<0.001). When comparing ΔFFR according to ΔBP or ΔHR between IV adenosine/ATP and IC nicorandil, there were no correlations, either between ΔFFR and ΔBP (r=-0.114, p=0.091), or between ΔFFR and ΔHR (r=1.000, p=0.151). CONCLUSIONS: Nicorandil IC bolus injection is a simple, safe and effective hyperaemic method for FFR measurement and can be used as a substitute for adenosine.

Integrated physiologic assessment of ischemic heart disease in real-world practice using index of microcirculatory resistance and fractional flow reserve: insights from the International Index of Microcirculatory Resistance Registry.

BACKGROUND: The index of microcirculatory resistance (IMR) is a quantitative and specific index for coronary microcirculation. However, the distribution and determinants of IMR have not been fully investigated in patients with ischemic heart disease (IHD). METHODS AND RESULTS: Consecutive patients who underwent elective measurement of both fractional flow reserve (FFR) and IMR were enrolled from 8 centers in 5 countries. Patients with acute myocardial infarction were excluded. To adjust for the influence of collateral flow, IMR values were corrected with Yong's formula (IMRcorr). High IMR was defined as greater than the 75th percentile in each of the major coronary arteries. FFR≤0.80 was defined as an ischemic value. 1096 patients with 1452 coronary arteries were analyzed (mean age 61.1, male 71.2%). Mean FFR was 0.84 and median IMRcorr was 16.6 U (Q1, Q3 12.4 U, 23.0 U). There was no correlation between IMRcorr and FFR values (r=0.01, P=0.62), and the categorical agreement of FFR and IMRcorr was low (kappa value=-0.04, P=0.10). There was no correlation between IMRcorr and angiographic % diameter stenosis (r=-0.03, P=0.25). Determinants of high IMR were previous myocardial infarction (odds ratio [OR] 2.16, 95% confidence interval [CI] 1.24-3.74, P=0.01), right coronary artery (OR 2.09, 95% CI 1.54-2.84, P<0.01), female (OR 1.67, 95% CI 1.18-2.38, P<0.01), and obesity (OR 1.80, 95% CI 1.31-2.49, P<0.01). Determinants of FFR ≤0.80 were left anterior descending coronary artery (OR 4.31, 95% CI 2.92-6.36, P<0.01), angiographic diameter stenosis ≥50% (OR 5.16, 95% CI 3.66-7.28, P<0.01), male (OR 2.15, 95% CI 1.38-3.35, P<0.01), and age (per 10 years, OR 1.21, 95% CI 1.01-1.46, P=0.04). CONCLUSIONS: IMR showed no correlation with FFR and angiographic lesion severity, and the predictors of high IMR value were different from those for ischemic FFR value. Therefore, integration of IMR into FFR measurement may provide additional insights regarding the relative contribution of macro- and microvascular disease in patients with ischemic heart disease. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02186093.