Assessment of Myocardial Viability in Ischemic Cardiomyopathy With Reduced Left Ventricular Function Undergoing Coronary Artery Bypass Grafting.

BACKGROUND: We aim to provide a comprehensive review of the current state of knowledge of myocardial viability assessment in patients undergoing coronary artery bypass grafting (CABG), with a focus on the clinical markers of viability for each imaging modality. We also compare mortality between patients with viable myocardium and those without viability who undergo CABG. METHODS: A systematic database search with meta-analysis was conducted of comparative original articles (both observations and randomized controlled studies) of patients undergoing CABG with either viable or nonviable myocardium, in EMBASE, MEDLINE, Cochrane database, and Google Scholar, from inception to 2022. Imaging modalities included were dobutamine stress echocardiography (DSE), cardiac magnetic resonance (CMR), single-photon emission computed tomography (SPECT), and positron emission tomography (PET). RESULTS: A total of 17 studies incorporating a total of 2317 patients were included. Across all imaging modalities, the relative risk of death post-CABG was reduced in patients with versus without viability (random-effects model: odds ratio: 0.42; 95% confidence interval: 0.29-0.61; p < 0.001). Imaging for myocardial viability has significant clinical implications as it can affect the accuracy of the diagnosis, guide treatment decisions, and predict patient outcomes. Generally, based on local availability and expertise, either SPECT or DSE should be considered as the first step in evaluating viability, while PET or CMR would provide further evaluation of transmurality, perfusion metabolism, and extent of scar tissue. CONCLUSION: The assessment of myocardial viability is an essential component of preoperative evaluation in patients with ischemic heart disease undergoing surgical revascularization. Careful patient selection and individualized assessment of viability remain paramount.

Angiographic Findings and Post-Percutaneous Coronary Intervention Fractional Flow Reserve.

Importance: The associations between angiographic findings and post-percutaneous coronary intervention (PCI) fractional flow reserve (FFR) and their clinical relevance according to residual functional disease burden have not been thoroughly investigated. Objectives: To evaluate the association of angiographic and physiologic parameters according to residual functional disease burden after drug-eluting stent implantation. Design, Setting, and Participants: This cohort study population was from the International Post-PCI FFR registry, which incorporated 4 registries from Korea, China, and Japan. Patients who underwent angiographically successful second-generation drug-eluting stent implantation and post-PCI FFR measurement were included in the analysis. The patients were divided into 3 groups according to the residual disease burden (post-PCI FFR ≤0.80 [residual ischemia], 0.81-0.86 [suboptimal], and >0.86 [optimal]). The data were collected from August 23, 2018, to June 11, 2019, and the current analysis was performed from January 11, 2022, to October 7, 2023. Exposures: Angiographic parameters and post-PCI FFR. Main Outcomes and Measures: The primary outcome was target vessel failure (TVF), defined as a composite of cardiac death, target vessel-related myocardial infarction, and target vessel revascularization (TVR) at 2 years. Results: In this cohort of 2147 patients, the mean (SD) age was 64.3 (10.0) years, and 1644 patients (76.6%) were men. Based on the post-PCI physiologic status, 269 patients (12.5%) had residual ischemia, 551 (25.7%) had suboptimal results, and 1327 (61.8%) had optimal results. Angiographic parameters had poor correlations with post-PCI FFR (r < 0.20). Post-PCI FFR was isolated from all angiographic parameters in the unsupervised hierarchical cluster analysis. Post-PCI FFR was associated with the occurrence of TVF (adjusted hazard ratio [AHR] per post-PCI FFR 0.01 increase, 0.94 [95% CI, 0.92-0.97]; P < .001), but angiographic parameters were not. The residual ischemia group had a significantly higher rate of TVF than the suboptimal group (AHR, 1.75 [95% CI, 1.08-2.83]; P = .02) and the optimal group (AHR, 2.94 [95% CI, 1.82-4.73]; P < .001). The TVR in the residual ischemia group was predominantly associated with TVR in the nonstented segment (14 [53.8%]), unlike the other 2 groups (3 [10.0%] in the suboptimal group and 13 [30.2%] in the optimal group). Conclusions and Relevance: In this cohort study of the International Post-PCI FFR registry, a low degree of associations were observed between angiographic and physiologic parameters after PCI. Post-PCI FFR, unlike angiographic parameters, was associated with clinical events and the distribution of clinical events. The current study supports the use of post-PCI FFR as a procedural quality metric and further prospective study is warranted.

Which Test Should I Order for an Inpatient Evaluation of Cardiac Ischemia?

AbstractTesting for cardiac ischemia, or for the obstructive coronary artery disease (CAD) that causes cardiac ischemia, is common among hospitalized patients. Many testing options exist. Choosing an appropriate test can be challenging and requires accurate risk stratification. Two major categories of testing are available: stress testing (also known as functional testing) and anatomical testing. Stress testing evaluates specifically for ischemia and can be conducted with or without imaging. Anatomical testing visualizes the obstructive CAD that causes ischemia. This article reviews how to choose an appropriate test for the evaluation of cardiac ischemia in the inpatient setting, using case examples to illustrate the considerations involved.

Stress-Induced Autonomic Dysfunction is Associated With Mental Stress-Induced Myocardial Ischemia in Patients With Coronary Artery Disease.

BACKGROUND: Mental stress-induced myocardial ischemia (MSIMI) is associated with adverse cardiovascular outcomes in individuals with coronary artery disease, but the mechanisms underlying this phenomenon are unknown. We examined the relationship between stress-induced autonomic dysfunction, measured by low heart rate variability (HRV) in response to stress, and MSIMI in patients with stable coronary artery disease. We hypothesized that stress-induced autonomic dysfunction is associated with higher odds of MSIMI. METHODS: In 735 participants with stable coronary artery disease, we measured high- and low-frequency HRV in 5-minute intervals before and during a standardized laboratory-based speech stressor using Holter monitoring. HRV at rest and stress were categorized into low HRV (first quartile) versus high HRV (second to fourth quartiles); the low category was used as an indicator of autonomic dysfunction. Multivariable logistic regression models were used to examine the association of autonomic dysfunction with MSIMI. RESULTS: The mean age was 58 (SD, ±10) years, 35% were women, 44% were Black participants, and 16% developed MSIMI. Compared with high HRV during stress, low HRV during stress (both high and low frequencies) was associated with higher odds of MSIMI after adjusting for demographic and clinical factors (odds ratio for high-frequency HRV, 2.1 [95% CI, 1.3-3.3]; odds ratio for low-frequency HRV, 2.1 [95% CI, 1.3-3.3]). Low-frequency HRV at rest was also associated with MSIMI but with slightly reduced effect estimates. CONCLUSIONS: In individuals with coronary artery disease, mental stress-induced autonomic dysfunction may be a mechanism implicated in the causal pathway of MSIMI.

Adoption of the cardiopulmonary exercise test in the exercise ability and cardiopulmonary function rehabilitation of coronary artery disease (CAD) patients.

BACKGROUND: This study aimed to explore the application of cardiopulmonary exercise testing in coronary artery disease (CAD) patients, evaluate its impact on exercise ability and cardiopulmonary function in patients with coronary heart disease (CHD), and promote the application of cardiopulmonary exercise testing in CAD management. METHODS: Fifty CHD patients after percutaneous coronary intervention (PCI) were recruited and randomly enrolled into the control (Ctrl) group and intervention (Int) group. Routine health education and health education combined with RT training were carried out for the two groups. Blood lipid levels and lung function were compared between the two groups after intervention. Cardiac function was evaluated by Doppler ultrasonography, and cardiopulmonary fitness and exercise ability were evaluated by a cardiopulmonary exercise test (CPET). The self-rating anxiety scale (SAS) and self-rating depression scale (SDS) were employed to evaluate negative emotions. The 36-item short-form (SF-36) was adopted to evaluate quality of life. RESULT: Compared with those in the Ctrl group, the levels of serum total cholesterol (TC), triglycerides (TGs), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) decreased in the Int group, while the levels of high-density lipoprotein increased (P < 0.05). The quantitative load results showed that compared with the Ctrl group, the heart rate (HR) and self-perceived fatigue degree of the Int group decreased, and the ST segment increased (P < 0.05). Compared with the Ctrl group, the left ventricular ejection fraction (LVEF), forced expiratory volume at 1 s (FEV1), ratio of forced expiratory volume to forced vital volume (FEV1/FVC%), and maximum chase volume (MVV) increased in the Int group, while the left ventricular end diastolic diameter and left ventricular end contractile diameter decreased (P < 0.05). The results of the CPET showed that compared with the Ctrl group, minute ventilation/carbon dioxide production slope, VE/VCO2 - Peak, anaerobic threshold (AT), peak oxygen pulse (VO2/HR peak), oxygen uptake efficiency platform (OUEP), increasing power exercise time (IPEt), HR recovery 1 min after exercise, peak load power (Watt peak), and value metabolic equivalent (Watt peak) increased in the Int group (P < 0.05). Compared with the Ctrl group, the SAS and SDS scores in the Int group decreased (P < 0.05). The results of the quality of life evaluation showed that compared with the Ctrl group, the score of the SF-36 dimensions increased in the Int group (P < 0.05). CONCLUSION: RT training can reduce postoperative blood lipid and quantitative load levels in CAD patients and improve adverse mood. Furthermore, it can improve patients' cardiopulmonary function, cardiopulmonary fitness, exercise ability, and quality of life.

Clinical impact of multimodality assessment of myocardial viability.

Coronary artery disease (CAD) is a prevalent cause of left ventricular dysfunction. Nevertheless, effective elective revascularization, particularly surgical revascularization, can enhance long-term outcomes and, in selected cases, global left ventricular contractility. The assessment of myocardial viability and scars is still relevant in guiding treatment decisions and selecting patients who are likely to benefit most from blood flow restoration. Although the most recent randomized studies challenge the notion of "hibernating myocardium" and the clinical usefulness of assessing myocardial viability, the advancement of imaging techniques still renders this assessment valuable in specific situations. According to the guidelines of the European Society of Cardiology, non-invasive stress imaging may be employed to define myocardial ischemia and viability in patients with CAD and heart failure before revascularization. Currently, several non-invasive imaging techniques are available to evaluate the presence and extent of viable myocardium. The selection of the most suitable technique should be based on the patient, clinical context, and resource availability. This narrative review evaluates the characteristics of available imaging modalities for assessing myocardial viability to determine the most appropriate therapeutic strategy.

Future of invasive and non-invasive hemodynamic assessment for coronary artery disease management.

Coronary artery disease represents a global health challenge. Accurate diagnosis and evaluation of hemodynamic parameters are crucial for optimizing patient management and outcomes. Nowadays a wide range of both non-invasive and invasive methods are available to assess the hemodynamic impact of both epicardial coronary stenosis and vasomotor disorders. In fact, over the years, important developments have reshaped the nature of both invasive and non-invasive diagnostic techniques, and the future holds promises for further innovation and integration. Non-invasive techniques have progressively evolved and currently a broad spectrum of methods are available, from cardiac magnetic resonance imaging with pharmacological stress and coronary computed tomography (CT) to the newer application of FFR-CT and perfusion CT. Invasive methods, on the contrary, have developed to a full-physiology approach, able not only to identify functionally significant lesions but also to evaluate microcirculation and vasospastic disease. The aim of this review is to summarize the current state-of-the-art of invasive and non-invasive hemodynamic assessment for CAD management.

Beyond Coronary Artery Disease: Assessing the Microcirculation.

Ischemic heart disease (IHD) affects more than 20 million adults in the United States. Although classically attributed to atherosclerosis of the epicardial coronary arteries, nearly half of patients with stable angina and IHD who undergo invasive coronary angiography do not have obstructive epicardial coronary artery disease. Ischemia with nonobstructive coronary arteries is frequently caused by microvascular angina with underlying coronary microvascular dysfunction (CMD). Greater understanding the pathophysiology, diagnosis, and treatment of CMD holds promise to improve clinical outcomes of patients with ischemic heart disease.

A lumped parameter model for evaluating coronary artery blood supply capacity.

The coronary artery constitutes a vital vascular system that sustains cardiac function, with its primary role being the conveyance of indispensable nutrients to the myocardial tissue. When coronary artery disease occurs, it will affect the blood supply of the heart and induce myocardial ischemia. Therefore, it is of great significance to numerically simulate the coronary artery and evaluate its blood supply capacity. In this article, the coronary artery lumped parameter model was derived based on the relationship between circuit system parameters and cardiovascular system parameters, and the blood supply capacity of the coronary artery in healthy and stenosis states was studied. The aortic root pressure calculated by the aortic valve fluid-structure interaction (AV FSI) simulator was employed as the inlet boundary condition. To emulate the physiological phenomenon of sudden pressure drops resulting from an abrupt reduction in blood vessel radius, a head loss model was connected at the coronary artery's entrance. For each coronary artery outlet, the symmetric structured tree model was appended to simulate the terminal impedance of the missing downstream coronary arteries. The particle swarm optimization (PSO) algorithm was used to optimize the blood flow viscous resistance, blood flow inertia, and vascular compliance of the coronary artery model. In the stenosis states, the relative flow and fractional flow reserve (FFR) calculated by numerical simulation corresponded to the published literature data. It was anticipated that the proposed model can be readily adapted for clinical application, serving as a valuable reference for diagnosing and treating patients.

[Association between body composition and coronary artery calcification in patients with chronic kidney disease].

Objective: To investigate the association between body composition and coronary artery calcification in patients with chronic kidney disease (CKD). Methods: This cross-sectional study enrolled patients with CKD hospitalized from May 2019 to April 2022 at Sun Yat-sen Memorial Hospital, Guangzhou, China. Skeletal muscle mass index and visceral fat area were measured by bioelectrical impedance analysis. Coronary artery calcification was assessed by computed tomography. Patients were divided into coronary artery calcification group and non-coronary artery calcification group according to the incidence of coronary artery calcification. Patients were categorized into tertile groups according to their skeletal muscle mass index and visceral fat area levels ranging from the lowest to the highest levels (T1 to T3). We defined skeletal muscle mass index≤30.4% as low muscle mass and visceral fat area≥80.6 cm2 as high visceral fat based on the results of the restricted cubic spline graph. All individuals were divided into 4 phenotypes: normal body composition, low muscle mass, high visceral fat, and low muscle mass with high visceral fat. Spearman correlation analysis and logistic regression analysis were used to assess the association between skeletal muscle mass index, visceral fat area and coronary artery calcification. Results: A total of 107 patients with CKD were enrolled, with an age of (60.0±14.1) years, including 41 female patients (38.3%). Patients of coronary artery calcification group had lower skeletal muscle mass index ((32.0±4.8) vs. (34.3±4.8), P=0.016) and higher visceral fat area ((70.8±32.6) cm2 vs. (47.9±23.8) cm2, P<0.001) than those of non-coronary artery calcification group. Patients in the T3 group of skeletal muscle mass index had a lower prevalence of coronary artery calcification (17 (48.6%) vs. 28 (77.8%)) and a lower coronary artery calcification score (0.5 (0, 124.0) vs. 12.0 (0.3, 131.0)) than those in the T1 group (P<0.05). Similarly, patients in the T1 group of visceral fat area had a lower prevalence of coronary artery calcification (14 (40.0%) vs. 29 (80.6%)) and a lower coronary artery calcification score (0 (0, 3.0) vs. 37.0 (2.0, 131.0)) than those in the T3 group (P<0.05). Likewise, patients with both low muscle mass and low muscle mass with high visceral fat had a higher prevalence of coronary artery calcification (11(78.6%) vs. 33 (47.8%); 15 (83.3%) vs. 33 (47.8%)) and a higher coronary artery calcification score (31.1 (0.8, 175.8) vs. 0 (0, 16.4); 27.6 (6.4, 211.4) vs. 0 (0, 16.4)) than those with normal body composition (P<0.05). Spearman correlation analysis showed that skeletal muscle mass index was inversely correlated with coronary artery calcification score (r=-0.212, P=0.028), and visceral fat area was positively correlated with coronary artery calcification score (r=0.408, P<0.001). Multivariate logistic regression analysis showed that increased skeletal muscle mass index was inversely associated with coronary artery calcification prevalence (T2: OR=0.208, 95%CI: 0.056-0.770, P=0.019; T3: OR=0.195, 95%CI: 0.043-0.887, P=0.034), and reduced visceral fat area was inversely associated with coronary artery calcification prevalence (T1: OR=0.256, 95%CI: 0.071-0.923, P=0.037; T2: OR=0.263, 95%CI: 0.078-0.888, P=0.031). Consistently, both low muscle mass and low muscle mass with high visceral fat were associated with coronary artery calcification prevalence (OR=6.616, 95%CI: 1.383-31.656, P=0.018; OR=5.548, 95%CI: 1.062-28.973, P=0.042). Conclusion: Reduced skeletal muscle mass index and increased visceral fat area are significantly associated with both the prevalence and severity of coronary artery calcification in patients with CKD.

Effects of left bundle branch block on echocardiographic coronary flow assessment: A systematic review.

This systematic review investigates the diagnostic and prognostic utility of coronary flow reserve (CFR) assessment through echocardiography in patients with left bundle branch block (LBBB), a condition known to complicate the clinical evaluation of coronary artery disease (CAD). The literature search was performed on PubMed, EMBASE, Web of Science, Scopus, and Google Scholar, was guided by PRISMA standards up to March 2024, and yielded six observational studies that met inclusion criteria. These studies involved a diverse population of patients with LBBB, employing echocardiographic protocols to clarify the impact of LBBB on coronary flow dynamics. The findings emphasize the importance of CFR in stratifying cardiovascular risk and guiding clinical decision-making in patients with LBBB. Pooled results reveal that patients with LBBB and significant left anterior descending (LAD) artery stenosis exhibited a marked decrease in stress-peak diastolic velocity (MD = -19.03 [-23.58; -14.48] cm/s; p < .0001) and CFR (MD = -.60 [-.71; -.50]; p < .0001), compared to those without significant LAD lesions, suggesting the efficacy of stress echocardiography CFR assessment in the identification of clinically significant CAD among the LBBB population. This review highlights the clinical relevance of echocardiography CFR assessment as a noninvasive tool for evaluating CAD and stratifying risk in the presence of LBBB and underscores the need for standardized protocols in CFR measurement.

The Plaque Analysis Classifies the Coronary Artery Disease-Reporting and Data System (CAD-RADS) Stenosis and Plaque Burden Categories: Association of the Plaque Features, Fat Attenuation Index, Coronary Computed Tomography Fractional Flow Reserve, and the Combination of Stenosis and Calcification.

BACKGROUND: The coronary artery disease-reporting and data system (CAD-RADS) 2.0 is used to standardize the reporting of coronary computed tomography angiography (CCTA) results. Artificial intelligence software can quantify the plaque composition, fat attenuation index, and fractional flow reserve. OBJECTIVE: To analyze plaque features of varying severity in patients with a combination of CAD-RADS stenosis and plaque burden categorization and establish a random forest classification model. METHODS: The data of 100 patients treated between April 2021 and February 2022 were retrospectively collected. The most severe plaque observed in each patient was the target lesion. Patients were categorized into three groups according to CAD-RADS: CAD-RADS 1-2 + P0-2, CAD-RADS 3-4B + P0-2, and CAD-RADS 3-4B + P3-4. Differences and correlations between variables were assessed between groups. AUC, accuracy, precision, recall, and F1 score were used to evaluate the diagnostic performance. RESULTS: A total of 100 patients and 178 arteries were included. The differences of computed tomography fractional flow reserve (CT-FFR) (H = 23.921, p < 0.001), the volume of lipid component (H = 12.996, p = 0.002), the volume of fibro-lipid component (H = 8.692, p = 0.013), the proportion of lipid component volume (H = 22.038, p < 0.001), the proportion of fibro-lipid component volume (H = 11.731, p = 0.003), the proportion of calcification component volume (H = 11.049, p = 0.004), and plaque type (χ2 = 18.110, p = 0.001) was statistically significant. CONCLUSION: CT-FFR, volume and proportion of lipid and fibro-lipid components of plaques, the proportion of calcified components, and plaque type were valuable for CAD-RADS stenosis + plaque burden classification, especially CT-FFR, volume, and proportion of lipid and fibro-lipid components. The model built using the random forest was better than the clinical model (AUC: 0.874 vs. 0.647).

Diagnostic Performance of Coronary Angiography Derived Computational Fractional Flow Reserve.

BACKGROUND: Computational fluid dynamics can compute fractional flow reserve (FFR) accurately. However, existing models are limited by either the intravascular hemodynamic phenomarkers that can be captured or the fidelity of geometries that can be modeled. METHODS AND RESULTS: This study aimed to validate a new coronary angiography-based FFR framework, FFRHARVEY, and examine intravascular hemodynamics to identify new biomarkers that could augment FFR in discerning unrevascularized patients requiring intervention. A 2-center cohort was used to examine diagnostic performance of FFRHARVEY compared with reference wire-based FFR (FFRINVASIVE). Additional biomarkers, longitudinal vorticity, velocity, and wall shear stress, were evaluated for their ability to augment FFR and indicate major adverse cardiac events. A total of 160 patients with 166 lesions were investigated. FFRHARVEY was compared with FFRINVASIVE by investigators blinded to the invasive FFR results with a per-stenosis area under the curve of 0.91, positive predictive value of 90.2%, negative predictive value of 89.6%, sensitivity of 79.3%, and specificity of 95.4%. The percentage ofdiscrepancy for continuous values of FFR was 6.63%. We identified a hemodynamic phenomarker, longitudinal vorticity, as a metric indicative of major adverse cardiac events in unrevascularized gray-zone cases. CONCLUSIONS: FFRHARVEY had high performance (area under the curve: 0.91, positive predictive value: 90.2%, negative predictive value: 89.6%) compared with FFRINVASIVE. The proposed framework provides a robust and accurate way to compute a complete set of intravascular phenomarkers, in which longitudinal vorticity was specifically shown to differentiate vessels predisposed to major adverse cardiac events.

WNT Signaling Cascade Proteins and LRP6 in the Formation of Various Types of Coronary Lesions in Patients With Coronary Artery Disease.

AIM: Assessment of WNT1, WNT3a, and LRP6 concentrations in patients with ischemic heart disease (IHD) and obstructive and non-obstructive coronary artery (CA) disease. MATERIAL AND METHODS: This cross-sectional observational study included 50 IHD patients (verified by coronary angiography, CAG), of which 25 (50%) were men, mean age 64.9±8.1 years; 20 patients had non-obstructive CA disease (stenosis <50%), and 30 patients had hemodynamically significant stenosis. Concentrations of WNT1, WNT3a and LRP6 were measured in all patients. RESULTS: The concentrations of WNT1 and WNT3a proteins were significantly higher in patients with IHD and obstructive CA disease (p < 0.001), while the concentration of LRP6 was higher in the group with non-obstructive CA disease (p = 0.016). Data analysis of the group with obstructive CA disease showed a moderate correlation between WNT1 and LRP6 (ρ=0.374; p=0.042). Correlation analysis of all groups of patients with CA disease revealed a moderate association between the concentrations of WNT1 and uric acid (ρ=0.416; p=0.007). Regression analysis showed that risk factors for the development of IHD, such as increased body mass index, age, smoking, dyslipidemia, and hypertension, did not significantly influence the type of CA disease in IHD patients. According to ROC analysis, the obstructive form of IHD was predicted by a WNT3a concentration higher than 0.155 ng/ml and a LRP6 concentration lower than 12.94 ng/ml. CONCLUSION: IHD patients with non-obstructive CA disease had the greatest increase in LRP6, while patients with obstructive CA disease had significantly higher concentrations of the canonical WNT cascade proteins, WNT1 and WNT3a. According to the ROC analysis, a WNT3a concentration >0.155 ng/ml can serve as a predictor for the presence of hemodynamically significant CA stenosis in IHD patients (sensitivity 96.7%; specificity 70%), whereas a LRP6 concentration >12.94 ng/ml can predict the development of non-obstructive CA disease (sensitivity 76.7%; specificity 65%).

Impact of hyperaemic stenosis resistance on long-term outcomes of stable angina in the ILIAS Registry.

BACKGROUND: The hyperaemic stenosis resistance (HSR) index was introduced to provide a more comprehensive indicator of the haemodynamic severity of a coronary lesion. HSR combines both the pressure drop across a lesion and the flow through it. As such, HSR overcomes the limitations of the more traditional fractional flow reserve (FFR) or coronary flow reserve (CFR) indices. AIMS: We aimed to identify the diagnostic and prognostic value of HSR and evaluate the clinical implications. METHODS: Patients with chronic coronary syndromes (CCS) and obstructive coronary artery disease were selected from the multicentre ILIAS Registry. For this study, only patients with combined Doppler flow and pressure measurements were included. RESULTS: A total of 853 patients with 1,107 vessels were included. HSR more accurately identified the presence of inducible ischaemia compared to FFR and CFR (area under the curve 0.71 vs 0.66 and 0.62, respectively; p<0.005 for both). An abnormal HSR measurement was an independent and important predictor of target vessel failure at 5-year follow-up (hazard ratio 3.80, 95% confidence interval: 2.12-6.73; p<0.005). In vessels deferred from revascularisation, HSR seems to identify more accurately those vessels that may benefit from revascularisation rather than FFR and/or CFR. CONCLUSIONS: The present study affirms the theoretical advantages of the HSR index for the detection of ischaemia-Âinducing coronary lesions in a large CCS population. (Inclusive Invasive Physiological Assessment in Angina Syndromes Registry [ILIAS Registry], ClinicalTrials.gov: NCT04485234).

Effects of age on microvascular function in patients with normal coronary arteries.

BACKGROUND: It has been suggested that coronary microvascular function decreases with age, irrespective of the presence of epicardial atherosclerosis. AIMS: Our aim is to quantitatively investigate the effects of age on microvascular function in patients with normal coronary arteries. METHODS: In 314 patients with angina with no obstructive coronary artery disease (ANOCA), microcirculatory function was tested using the continuous thermodilution method. In 305 patients, the association between age and both resting and hyperaemic myocardial blood flow (Q), microvascular resistance (Rµ), absolute coronary flow reserve (CFR) and microvascular resistance reserve (MRR) was assessed. In addition, patients were divided into 3 groups to test for differences based on age quartiles (≤52 years [24.9%], 53-64 years [49.2%], ≥65 years [25.9%]). RESULTS: The mean age was 59±9 years with a range from 22 to 79 years. The mean resting Q (Qrest) was not different in the 3 age groups (88±34 mL/min, 82±29 mL/min, and 86±38 mL/min, R2=0.001; p=0.62). A trend towards a decreasing mean hyperaemic Q (Qmax) was observed with increasing age (223±79 mL/min, 209±84 mL/min, 200±80 mL/min, R2=0.010; p=0.083). The mean resting Rµ (Rµ,rest) were 1,204±460 Wood units (WU), 1,260±411 WU, and 1,289±455 WU (p=0.23). The mean hyperaemic Rµ (Rµ,hyp) increased significantly with advancing age (429±149 WU, 464±164 WU, 503±162 WU, R2=0.026; p=0.005). Consequently, MRR decreased with age (3.2±1.2, 3.1±1.0, 2.9±0.9; p=0.038). This trend was present in both the patients with (n=121) and without (n=184) coronary microvascular dysfunction (CMD). CONCLUSIONS: There is an age-dependent physiological increase in minimal microvascular resistance and decrease in microvascular function, which is represented by a decreased MRR and is independent of atherosclerosis. The age-dependent decrease in MRR was present in both patients with and without CMD and was most evident in patients with smooth coronary arteries.

Prognostic Value of Microvascular Resistance Reserve Measured Immediately After PCI in Stable Coronary Artery Disease.

BACKGROUND: Microvascular resistance reserve (MRR) has been proposed as a specific metric to quantify coronary microvascular function. The long-term prognostic value of MRR measured in stable patients immediately after percutaneous coronary intervention (PCI) is unknown. This study sought to determine the prognostic value of MRR measured immediately after PCI in patients with stable coronary artery disease. METHODS: This study included 502 patients with stable coronary artery disease who underwent elective PCI and coronary physiological measurements, including pressure and flow estimation using a bolus thermodilution method after PCI. MRR was calculated as coronary flow reserve divided by fractional flow reserve times the ratio of mean aortic pressure at rest to that at maximal hyperemia induced by hyperemic agents. An abnormal MRR was defined as ≤2.5. Major adverse cardiac events (MACEs) were defined as a composite of all-cause mortality, any myocardial infarction, and target-vessel revascularization. RESULTS: During a median follow-up of 3.4 years, the cumulative MACE rate was significantly higher in the abnormal MRR group (12.5 versus 8.3 per 100 patient-years; hazard ratio 1.53 [95% CI, 1.10-2.11]; P<0.001). A higher all-cause mortality rate primarily drove this difference. On multivariable analysis, a higher MRR value was independently associated with lower MACE and lower mortality. When comparing 4 subgroups according to MRR and the index of microcirculatory resistance, patients with both abnormal MRR and index of microcirculatory resistance (≥25) had the highest MACE rate. CONCLUSIONS: An abnormal MRR measured immediately after PCI in patients with stable coronary artery disease is an independent predictor of MACE, particularly all-cause mortality.

Agreement of Fractional Flow Reserve Estimated by Computed Tomography With Invasively Measured Fractional Flow Reserve: A Systematic Review and Meta-Analysis.

BACKGROUND: Fractional flow reserve (FFR) is the ratio of blood pressure measured distal to a stenosis and pressure proximal to a stenosis. FFR can be estimated noninvasively using computed tomography (CT) although the usefulness of this technique remains controversial. This meta-analysis evaluated the agreement of FFR estimated by CT (FFR-CT) with invasively measured FFR. The study also evaluated the diagnostic accuracy of FFR-CT, defined as the ability of FFR-CT to classify lesions as hemodynamically significant (invasive FFR ≤0.8) or insignificant (invasive FFR >0.8). METHODS AND RESULTS: Forty-three studies reporting on 7291 blood vessels from 5236 patients were included. A moderate positive linear relationship between FFR-CT and invasively measured FFR was observed (Spearman correlation coefficient: 0.67). Agreement between the 2 measures increased as invasively measured FFR values approached 1. The overall diagnostic accuracy, sensitivity and specificity of FFR-CT were 82.2%, 80.9%, and 83.1%, respectively. Diagnostic accuracy of 90% could be demonstrated for FFR-CT values >0.90 and <0.49. The diagnostic accuracy of off-site tools was 79.4% and the diagnostic accuracy of on-site tools was 84.1%. CONCLUSIONS: The agreement between FFR-CT and invasive FFR is moderate although agreement is highest in vessels with FFR-CT >0.9. Diagnostic accuracy varies widely with FFR-CT value but is above 90% for FFR-CT values >0.90 and <0.49. Furthermore, on-site and off-site tools have similar performance. Ultimately, FFR-CT may be a useful adjunct to CT coronary angiography as a gatekeeper for invasive coronary angiogram.