Coronary microvascular dysfunction in stable ischaemic heart disease (non-obstructive coronary artery disease and obstructive coronary artery disease)

Enhancing Endothelial Function with Nutrient-Enriched Table Hen Eggs: A Randomized Study in Patients Recovering from Acute Coronary Syndrome

Purpose

This study investigated the effect of consumption of table eggs enriched with n-3 polyunsaturated fatty acids (n-3 PUFA), lutein, vitamin E and selenium on microvascular function, oxidative stress and inflammatory mediators in patients after acute coronary syndrome (ACS).

Patients and Methods

In a prospective, randomized, interventional, double-blind clinical trial, ACS patients were assigned to either the Nutri4 (N=15, mean age: 57.2 ± 9.2 years), or the Control group (N=13; mean age 56.8 ± 9.6 years). The Nutri4 group consumed three enriched hen eggs daily for three weeks, providing approximately 1.785 mg of vitamin E, 0.330 mg of lutein, 0.054 mg of selenium and 438 mg of n-3 PUFAs. Biochemical parameters, including serum lipids, liver enzymes, nutrient concentrations, serum antioxidant enzyme activity (catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD)), and markers of oxidative stress (thiobarbituric acid reactive substances (TBARS) and ferric reducing ability (FRAP)), were assessed before and after the dietary interventions. Additionally, arterial blood pressure, heart rate, body composition, fluid status, anthropometric measurements, and skin microvascular blood flow responses to various stimuli (postocclusive reactive hyperemia (PORH), acetylcholine- (Ach ID), and sodium nitroprusside- (SNP ID)) were measured using laser Doppler flowmetry (LDF) throughout the study.

Results

The intake of Nutri4 eggs led to a significant reduction in LDL cholesterol levels, while the levels of total cholesterol remained within the established reference values. Consuming Nutri4 eggs resulted in a 12.7% increase in serum vitamin E levels, an 8.6% increase in selenium levels, and demonstrated a favorable impact on microvascular reactivity, as evidenced by markedly improved PORH and ACh ID. Nutri4 eggs exerted a significant influence on the activity of GPx and SOD, with no observed changes in TBARS or FRAP values.

Conclusion

The consumption of Nutri4 eggs positively influenced microvascular function in individuals with ACS, without eliciting adverse effects on oxidative stress.

The additive effect of metabolic syndrome on left ventricular impairment in patients with obstructive coronary artery disease assessed by 3.0 T cardiac magnetic resonance feature tracking

BACKGROUND

Metabolic syndrome (MetS) can increase the risk of morbidity and mortality of cardiovascular disease and obstructive coronary artery disease (OCAD), which usually have a poor prognosis. This study aimed to explore the impact of MetS on left ventricular (LV) deformation and function in OCAD patients and investigate the independent factors of impaired LV function and deformation.

MATERIALS AND METHODS

A total of 121 patients with OCAD and 52 sex- and age-matched controls who underwent cardiac magnetic resonance scanning were enrolled in the study. All OCAD patients were divided into two groups: OCAD with MetS [OCAD(MetS+), n = 83] and OCAD without MetS [OCAD(MetS-), n = 38]. LV functional and global strain parameters were measured and compared among the three groups. Multivariable linear regression analyses were constructed to investigate the independent factors of LV impairment in OCAD patients. Logistic regression analysis and receiver operating characteristic (ROC) curve analysis were performed to test the prediction efficiency of MetS for LV impairment.

RESULTS

From controls to the OCAD(MetS-) group to the OCAD(MetS+) group, LV mass (LVM) increased, and LV global function index (LVGFI) and LV global longitudinal peak strain (GLPS) decreased (all p < 0.05). Compared with the OCAD(MetS-) group, the LV GLPS declined significantly (p = 0.027), the LVM increased (p = 0.006), and the LVGFI decreased (p = 0.043) in the OCAD(MetS+) group. After adjustment for covariates in OCAD patients, MetS was an independent factor of decreased LV GLPS (β = - 0.211, p = 0.002) and increased LVM (β = 0.221, p = 0.003). The logistic multivariable regression analysis and ROC analysis showed that combined MetS improved the efficiency of predicting LV GLPS reduction (AUC = 0.88) and LVM (AUC = 0.89) increase.

CONCLUSIONS

MetS aggravated the damage of LV deformation and function in OCAD patients and was independently associated with LV deformation and impaired LV strain. Additionally, MetS increased the prediction efficiency of increased LVM and decreased LV GLPS. Early detection and intervention of MetS in patients with OCAD is of great significance.

Genetic associations of cardiovascular risk genes in European patients with coronary artery spasm

BACKGROUND

Coronary artery spasm (CAS) is a frequent finding in patients presenting with angina pectoris. Although the pathogenesis of CAS is incompletely understood, previous studies suggested a genetic contribution. Our study aimed to elucidate genetic variants in a cohort of European patients with angina and unobstructed coronary arteries who underwent acetylcholine (ACh) provocation testing.

METHODS

A candidate association analysis of 208 genes previously associated with cardiovascular conditions was performed using genotyped and imputed variants in patients grouped in epicardial (focal, diffuse) CAS (n = 119) and microvascular CAS (n = 87). Patients with a negative ACh test result (n = 45) served as controls.

RESULTS

We found no association below the genome-wide significance threshold of p < 5 × 10-8, thus not confirming variants in ALDH2, NOS3, and ROCK2 previously reported in CAS patients of Asian ancestry. However, the analysis identified suggestive associations (p < 10-05) for the groups of focal epicardial CAS (CDH13) and diffuse epicardial CAS (HDAC9, EDN1). Downstream analysis of the potential EDN1 risk locus showed that CAS patients have significantly increased plasma endothelin-1 levels (ET-1) compared to controls. An EDN1 haplotype comprising rs9349379 and rs2070698 was significantly associated to ET-1 levels (p = 0.01).

CONCLUSIONS

In summary, we suggest EDN1 as potential genetic risk loci for patients with diffuse epicardial CAS, and European ancestry. Plasma ET-1 levels may serve as a potential cardiac marker.

Nonischemic or Dual Cardiomyopathy in Patients With Coronary Artery Disease

BACKGROUND

Randomized trials in obstructive coronary artery disease (CAD) have largely shown no prognostic benefit from coronary revascularization. Although there are several potential reasons for the lack of benefit, an underexplored possible reason is the presence of coincidental nonischemic cardiomyopathy (NICM). We investigated the prevalence and prognostic significance of NICM in patients with CAD (CAD-NICM).

METHODS

We conducted a registry study of consecutive patients with obstructive CAD on coronary angiography who underwent contrast-enhanced cardiovascular magnetic resonance imaging for the assessment of ventricular function and scar at 4 hospitals from 2004 to 2020. We identified the presence and cause of cardiomyopathy using cardiovascular magnetic resonance imaging and coronary angiography data, blinded to clinical outcomes. The primary outcome was a composite of all-cause death or heart failure hospitalization, and secondary outcomes were all-cause death, heart failure hospitalization, and cardiovascular death.

RESULTS

Among 3023 patients (median age, 66 years; 76% men), 18.2% had no cardiomyopathy, 64.8% had ischemic cardiomyopathy (CAD+ICM), 9.3% had CAD+NICM, and 7.7% had dual cardiomyopathy (CAD+dualCM), defined as both ICM and NICM. Thus, 16.9% had CAD+NICM or dualCM. During a median follow-up of 4.8 years (interquartile range, 2.9, 7.6), 1116 patients experienced the primary outcome. In Cox multivariable analysis, CAD+NICM or dualCM was independently associated with a higher risk of the primary outcome compared with CAD+ICM (adjusted hazard ratio, 1.23 [95% CI, 1.06-1.43]; P=0.007) after adjustment for potential confounders. The risks of the secondary outcomes of all-cause death and heart failure hospitalization were also higher with CAD+NICM or dualCM (hazard ratio, 1.21 [95% CI, 1.02-1.43]; P=0.032; and hazard ratio, 1.37 [95% CI, 1.11-1.69]; P=0.003, respectively), whereas the risk of cardiovascular death did not differ from that of CAD+ICM (hazard ratio, 1.15 [95% CI, 0.89-1.48]; P=0.28).

CONCLUSIONS

In patients with CAD referred for clinical cardiovascular magnetic resonance imaging, NICM or dualCM was identified in 1 of every 6 patients and was associated with worse long-term outcomes compared with ICM. In patients with obstructive CAD, coincidental NICM or dualCM may contribute to the lack of prognostic benefit from coronary revascularization.

Myocardial ischemia/reperfusion: Translational pathophysiology of ischemic heart disease

Ischemic heart disease is the greatest health burden and most frequent cause of death worldwide. Myocardial ischemia/reperfusion is the pathophysiological substrate of ischemic heart disease. Improvements in prevention and treatment of ischemic heart disease have reduced mortality in developed countries over the last decades, but further progress is now stagnant, and morbidity and mortality from ischemic heart disease in developing countries are increasing. Significant problems remain to be resolved and require a better pathophysiological understanding. The present review attempts to briefly summarize the state of the art in myocardial ischemia/reperfusion research, with a view on both its coronary vascular and myocardial aspects, and to define the cutting edges where further mechanistic knowledge is needed to facilitate translation to clinical practice.

Chinese expert consensus on the diagnosis and treatment of coronary microvascular diseases (2023 Edition)

Since the four working groups of the Chinese Society of Cardiology issued first expert consensus on coronary microvascular diseases (CMVD) in 2017, international consensus documents on CMVD have increased rapidly. Although some of these documents made preliminary recommendations for the diagnosis and treatment of CMVD, they did not provide classification of recommendations and levels of evidence. In order to summarize recent progress in the field of CMVD, standardize the methods and procedures of diagnosis and treatment, and identify the scientific questions for future research, the four working groups of the Chinese Society of Cardiology updated the 2017 version of the Chinese expert consensus on CMVD and adopted a series of measures to ensure the quality of this document. The current consensus has raised a new classification of CMVD, summarized new epidemiological findings for different types of CMVD, analyzed key pathological and molecular mechanisms, evaluated classical and novel diagnostic technologies, recommended diagnostic pathways and criteria, and therapeutic strategies and medications, for patients with CMVD. In view of the current progress and knowledge gaps of CMVD, future directions were proposed. It is hoped that this expert consensus will further expedite the research progress of CMVD in both basic and clinical scenarios.

Global trend and future landscape of coronary microcirculation: A bibliometric and visualized analysis from 1990 to 2021

Background

Coronary microcirculation has a fundamental role in the regulation of coronary blood flow in response to cardiac requirements, which has aroused wide concerns in basic science and clinical cardiovascular research. We aimed to analyze coronary microcirculation-associated literatures over 30 years and provide insightful information on the evolutionary path, frontier research hotspots, and future developmental trends.

Methods

Publications were retrieved from the Web of Science Core Collection (WoSCC). VOSviewer was used to perform co-occurrence analyses for countries, institutions, authors, and keywords and to generate visualized collaboration maps. CiteSpace was used to visualize the knowledge map derived from reference co-citation analysis, burst references, and keywords detection.

Results

This analysis was performed based on 11,702 publications including 9981 articles and 1721 reviews. The United States and Harvard University ranked at the top among all the countries and institutions. The majority of articles were published in Circulation, and it also was the most co-cited journal. Thematic hotspots and frontiers were focused on coronary microvascular dysfunction, magnetic resonance imaging, fractional flow reserve, STEMI, and heart failure. Additionally, keywords burst and co-occurrence cluster analysis showed that management, microvascular dysfunction, microvascular obstruction, prognostic value, outcomes, and guidelines were current knowledge gaps and future directions.

Conclusions

Coronary microcirculation presented a research hotspot relevant wide spectrum of cardiovascular diseases. Definite diagnostics and prognostics are particularly valued. The protection of cardiovascular events that influence clinical outcomes should be an insightful concern in the future. Multidisciplinary collaborations will provide significant advances for the development of coronary microcirculation.

The spectrum of angiography-derived IMR according to morphological and physiological coronary stenosis in patients with suspected myocardial ischemia

BACKGROUND

Coronary microvascular dysfunction is crucial in determining myocardial ischemia; however, the relationship between epicardial coronary diameter stenosis (DS) and the index of microcirculatory resistance (IMR) remains unclear. We sought to explore the distribution of coronary angiography-derived IMR (angio-IMR) in patients with suspected myocardial ischemia.

METHODS

The study included 480 patients with suspected myocardial ischemia, all of whom underwent coronary angiography. According to the severity of coronary DS, patients were divided into three groups: mild (DS < 50%), intermediate (DS 50%-70%), and severe (DS > 70%). Angio-IMR and fractional flow reserve (FFR) were calculated based on coronary angiography images through the principle of computational flow and pressure simulation.

RESULTS

Of the 480 patients, the mean age was 67.23 ± 9.44 years, with 55.4% male. There were 193 (40.2%) patients in the mild group, 189 (39.4%) patients in the intermediate group, and 98 (20.4%) patients in the severe group. The average angio-IMR of the mild group was 30.8 ± 14.9, which was significantly higher than those of the intermediate group (26.7 ± 13.0) and the severe group (17.9 ± 8.4) (p < .001). In the correlation analysis, angio-IMR was negatively correlated with DS (rho = -0.331, p = .001) and positively correlated with angio-FFR (rho = 0.483, p < .001). By multivariate logistic regression analysis, angio-FFR ≤ 0.8 (odds ratio, 0.184; 95% confidence interval, 0.106-0.321) was the only independent predictor of coronary microvascular dysfunction.

CONCLUSION

In patients with suspected myocardial ischemia, coronary microcirculation is significantly associated with morphological and physiological coronary stenosis. (ClinicalTrials.gov: NCT05435898).

Microvascular resistance reserve in the presence of functionally significant epicardial stenosis and changes after revascularization

In the presence of functionally significant epicardial lesions, microvascular resistance reserve (MRR) calculation needs incorporation of collateral flow. Coronary fractional flow reserve (FFRcor ) requiring coronary wedge pressure (Pw ), which is an essential part of the true MRR calculation, is reportedly estimated by myocardial FFR (FFRmyo ) not requiring Pw measurement. We sought to find an equation to calculate MRR without the need for Pw . Furthermore, we assessed changes in MRR after percutaneous coronary intervention (PCI). An equation to estimate FFRcor was developed from a cohort of 230 patients who underwent physiological measurements and PCI. Corrected MRR was calculated using this equation and compared with true MRR in 115 patients of the different set of the validation cohort. True MRR was calculated using FFRcor . FFRcor and FFRmyo showed a strong linear relationship (r2  = 0.86) and an equation was FFRcor  = 1.36 × FFRmyo - 0.34. This equation provided no significant difference between corrected MRR and true MRR in the validation cohort. Pre-PCI lower coronary flow reserve and higher index of microcirculatory resistance were independent predictors of pre-PCI decreased true MRR. True MRR significantly decreased after PCI. In conclusion, MRR can be accurately corrected using an equation for FFRcor estimation without Pw .

Evolving Management Paradigm for Stable Ischemic Heart Disease Patients: JACC Review Topic of the Week

Management of stable coronary artery disease (CAD) has been based on the assumption that flow-limiting atherosclerotic obstructions are the proximate cause of angina and myocardial ischemia in most patients and represent an important target for revascularization. However, the role of revascularization in reducing long-term cardiac events in these patients has been limited mainly to those with left main disease, 3-vessel disease with diabetes, or decreased ejection fraction. Mounting evidence indicates that nonepicardial coronary causes of angina and ischemia, including coronary microvascular dysfunction, vasospastic disorders, and derangements of myocardial metabolism, are more prevalent than flow-limiting stenoses, raising concerns that many important causes other than epicardial CAD are neither considered nor probed diagnostically. There is a need for a more inclusive management paradigm that uncouples the singular association between epicardial CAD and revascularization and better aligns diagnostic approaches that tailor treatment to the underlying mechanisms and precipitants of angina and ischemia in contemporary clinical practice.

Coronary microvascular dysfunction: A review of recent progress and clinical implications

The coronary microcirculation plays a cardinal role in regulating coronary blood flow to meet the changing metabolic demands of the myocardium. Coronary microvascular dysfunction (CMD) refers to structural and functional remodeling of the coronary microcirculation. CMD plays a role in the pathogenesis of obstructive and non-obstructive coronary syndromes as well as myocardial diseases, including heart failure with preserved ejection fraction (HFpEF). Despite recent diagnostic advancements, CMD is often under-appreciated in clinical practice, and may allow for the development of novel therapeutic targets. This review explores the diagnosis and pathogenic role of CMD across a range of cardiovascular diseases, its prognostic significance, and the current therapeutic landscape.

Computing intracoronary blood flow rate under incomplete boundary conditions: Combing coronary anatomy and fractional flow reserve

BACKGROUND

Accurate measurement of intracoronary blood flow rate is of great significance for the diagnosis of ischemic heart disease (IHD). Computational fluid dynamic (CFD) method, combining coronary angiography images and fractional flow reserve (FFR), provides a new way to calculate the mean flow rate. However, due to the incomplete boundary conditions obtained by FFR, side branches were ignored which was likely to have a significant impact on the accuracy. In this paper, a novel CFD based method for calculating the mean intracoronary flow rate under incomplete pressure boundary conditions was proposed, in order to improve the accuracy by including the side branches.

METHODS

A pressure-flow curve based flow resistance model was employed to model resistance of the epicardial arteries. A series of steady flow simulations were performed to extract the parameters of the flow resistance model, which implicitly specified constraints for splitting flow between branches and thus enabled the mean intracoronary blood flow rate to be calculated in two or more branches under incomplete pressure boundary conditions. Simulation experiments were designed to validate the proposed method in both idealized and reconstructed 3D models of coronary branches, and the impact of the assumed coefficient of the Murray's Law for splitting flow between branches was also investigated.

RESULTS

The mean percentage error of the proposed method was +2.05%±0.04% for idealized models and +2.24%±0.01% for reconstructed models, and it was much lower than that of the method ignoring side branches (+38.48%±10.45% for idealized models and +30.54%±6.12% for reconstructed models). When the assumed coefficient of the Murray's Law was inconsistent with the real blood flow condition, the percentage errors still maintained less than about 3.00%.

CONCLUSIONS

The proposed method provided an easy and accurate way to measure the mean intracoronary flow rate and would facilitate the accurate diagnosis of IHD.

Critical role of the coronary microvasculature in heart disease: From pathologic driving force to "innocent" bystander

The coronary microvasculature is responsible for providing oxygen and nutrients to myocardial tissue. A healthy microvasculature with an intact and properly functioning endothelium accomplishes this by seemless changes in vascular tone to match supply and demand. Perturbations in the normal physiology of the microvasculature, including endothelial and/or vascular smooth muscle dysfunction, result in impaired function (vasoconstriction, antithrombotic, etc.) and structural (hypertrophic, fibrotic) abnormalities that lead to microvascular ischemia and potential organ damage. While coronary microvascular dysfunction (CMD) is the primary pathologic driving force in ischemia with non-obstructive coronary artery disease (INOCA), angina with no obstructive coronary arteries (ANOCA), and myocardial infarction with non-obstructed coronary arteries (MINOCA), it may be a bystander in many cardiac disorders which later become pathologically associated with signs and/or symptoms of myocardial ischemia. Importantly, regardless of the primary or secondary basis of CMD in the heart, it is associated with important increases in morbidity and mortality. In this review we discuss salient features pertaining to known pathophysiologic mechanisms driving CMD, the spectrum of heart diseases where it places a critical role, invasive and non-invasive diagnostic testing, management strategies, and the gaps in knowledge where future research efforts are needed.

Risk Factors Predisposing to Angina in Patients with Non-Obstructive Coronary Arteries: A Retrospective Analysis

No hemodynamically significant atherosclerotic plaques are observed in up to 30% of patients reporting angina and undergoing coronary angiography. To investigate risk factors associated with non-obstructive coronary artery disease (NOCAD), we analyzed the medical records of, consecutively, 136 NOCAD subjects and 128 patients with significant stenosis in at least one coronary artery (the OCAD group). The blood concentrations of the TC (4.40 [3.78−5.63] mmol/L vs. 4.12 [3.42−5.01] mmol/L; p = 0.026), LDL-C (2.32 [1.80−3.50] mmol/L vs. 2.10 [1.50−2.70] mmol/L; p = 0.003), non-HDL-C (2.89 [2.29−4.19] mmol/L vs. 2.66 [2.06−3.39] mmol/L; p = 0.045), as well as the LDL-C/HDL-C ratio (1.75 [1.22−2.60] vs. 1.50 [1.10−1.95]; p = 0.018) were significantly increased in the NOCAD patients compared to the OCAD group due to the lower prevalence and intensity of the statin therapy in the NOCAD individuals (p < 0.001). Moreover, the abovementioned lipid parameters appeared to be valuable predictors of NOCAD, with the LDL-C (OR = 1.44; 95%CI = 1.14−1.82) and LDL-C/HDL-C (OR = 1.51; 95%CI = 1.13−2.02) showing the highest odds ratios. Furthermore, multivariable logistic regression models determined female sex as the independent risk factor for NOCAD (OR = 2.37; 95%CI = 1.33−4.20). Simultaneously, arterial hypertension substantially lowered the probability of NOCAD (OR = 0.21; 95%CI = 0.10−0.43). To conclude, female sex, the absence of arterial hypertension, as well as increased TC, LDL-C, non-HDL, and LDL-C/HDL-C ratio are risk factors for NOCAD in patients reporting angina, potentially as a result of poor hypercholesterolemia management.

Stress Perfusion Cardiac Magnetic Resonance in Long-Standing Non-Infarcted Chronic Coronary Syndrome with Preserved Systolic Function

(1) Background: The impact of imaging-derived ischemia is still under debate and the role of stress perfusion cardiac magnetic resonance (spCMR) in non-high-risk patient still needs to be clarified. The aim of this study was to evaluate the impact of spCMR in a case series of stable long-standing chronic coronary syndrome (CCS) patients with ischemia and no other risk factor. (2) Methods: This is a historical prospective study including 35 patients with history of long-standing CCS who underwent coronary CT angiography (CCTA) and additional adenosine spCMR. Clinical and imaging findings were included in the analysis. Primary outcomes were HF (heart failure) and all major cardiac events (MACE) including death from cardiovascular causes, myocardial infarction, or hospitalization for unstable angina, or resuscitated cardiac arrest. (3) Results: Mean follow-up was 3.7 years (IQR: from 1 to 6). Mean ejection fraction was 61 ± 8%. Twelve patients (31%) referred primary outcomes. Probability of experiencing primary outcomes based on symptoms was 62% and increased to 67% and 91% when multivessel disease and ischemia, respectively, were considered. Higher ischemic burden was predictive of disease progression (OR: 1.59, 95%CI: 1.18–2.14; p-value = 0.002). spCMR model resulted non inferior to the model comprising all variables (4) Conclusions: In vivo spCMR-modeling including perfusion and strain anomalies could represent a powerful tool in long-standing CCS, even when conventional imaging predictors are missing.

The adverse impact of coronary artery disease on left ventricle systolic and diastolic function in patients with type 2 diabetes mellitus: a 3.0T CMR study

Background

Coronary artery disease (CAD) confers considerable morbidity and mortality in diabetes. However, the role of CAD in additive effect of left ventricular (LV) function has rarely been explored in type 2 diabetes mellitus (T2DM) patients. This study aimed to investigate how CAD affect LV systolic and diastolic function in T2DM patients.

Materials and methods

A total of 282 T2DM patients {104 patients with CAD [T2DM (CAD +)] and 178 without [T2DM (CAD −)]} and 83 sex- and age- matched healthy controls underwent cardiac magnetic resonance scanning. LV structure, function, global strains [including systolic peak strain (PS), peak systolic (PSSR) and diastolic strain rate (PDSR) in radial, circumferential and longitudinal directions] and late gadolinium enhancement (LGE) parameters were measured. T2DM (CAD +) patients were divided into two subgroups based on the median of Gensini score (60) which was calculated to assess the severity of CAD. Multivariable linear regression analyses were constructed to investigate the determinants of reduced LV function.

Results

Compared with normal controls, T2DM (CAD −) patients exhibited increased LV end-diastolic and end-systolic volume index and decreased LV global strains, while T2DM(CAD +) patients showed more marked increase and decrease than T2DM(CAD-) and healthy controls, except for longitudinal PDSR (PDSR-L) (all P < 0.017). All of LV global strains demonstrated a progressive decrease from normal controls, through Gensini score ≤ 60, to Gensini score > 60 group, except for PDSR-L (all P < 0.017). CAD was an independent predictor of reduced LV global circumferential PS (GCPS, β = 0.22, p < 0.001), PSSR (PSSR-C, β = 0.17, p = 0.005), PDSR (PDSR-C, β = 0.22, p < 0.001), global radial PS (GRPS, β = 0.19, p = 0.001), and global longitudinal PS (GLPS, β = 0.18, p = 0.003) in T2DM. The Gensini score was associated with decreased GCPS, PSSR-C, PDSR-C, GRPS, and GLPS in T2DM (CAD +) (all p < 0.05).

Conclusion

CAD has an additive deleterious effect on LV systolic and diastolic function in T2DM patients. Among T2DM (CAD +) patients, the Gensini score is associated with reduced LV contractile and diastolic function.

Trial registration Retrospectively registered

Principles and pitfalls in coronary vasomotor function testing

BACKGROUND

Coronary vasomotor dysfunction can be diagnosed in a large proportion of patients with angina in the presence of non-obstructive coronary artery disease (ANOCA) using comprehensive protocols for coronary vasomotor function testing (CFT). Although consensus on diagnostic criteria for endotypes of coronary vasomotor dysfunction has been published, consensus on a standardised study testing protocol is lacking.

AIMS

In this review we provide an overview of the variations in CFT used and discuss the practical principles and pitfalls of CFT.

METHODS

For the purposes of this review, we assessed study protocols that evaluate coronary vasomotor response as reported in the literature. We compared these protocols regarding a number of procedural aspects and chose six examples to highlight the differences and uniqueness.

RESULTS

Currently, numerous protocols co-exist and vary in vascular domains tested, the manner in which to test these domains (e.g., preprocedural discontinuation of medication, provocative agent, solution, infusion time, and target artery) and techniques used for measurements (e.g., Doppler vs thermodilution technique).

CONCLUSIONS

This lack of consensus on a uniform functional testing protocol hampers both a broader clinical acceptance of the concepts of coronary vasomotor dysfunction, and the widespread adoption of such testing protocols in current clinical practice. Furthermore, the endotype of coronary vasomotor dysfunction might differ among the few specialised centres that perform CFT as a result of the use of different protocols.

Ist die weibliche koronare Mikrovaskulatur anders?

Viele Frauen mit Angina pectoris haben keine stenosierende koronare Herzerkrankung. Oft liegen der Symptomatik koronare Funktionsstörungen zugrunde, die wiederum häufig die koronare Mikrovaskulatur betreffen. Zu unterscheiden ist zwischen mikrovaskulären Störungen der Vasodilatation bzw. der Vasokonstriktion, wobei letztere häufiger sind. Die genaue Diagnose erfordert in aller Regel invasive Funktionstests mit Applikation von Adenosin bzw. Acetylcholin. Die Testergebnisse erlauben die Einteilung in Endotypen, die wiederum die Basis für eine angepasste und daher erfolgreiche medikamentöse Therapie sind. Es wurde spekuliert, dass die weibliche Mikrovaskulatur anders aufgebaut sein bzw. anders funktionieren könne als die männliche. Wahrscheinlich ist der wesentliche Unterschied aber die schnellere und daher frühere Entwicklung epikardialer stenosierender Läsionen bei Männern, bei denen dann nicht weiter nach dem Zustand der Mikrovaskulatur geschaut wird. Dafür spricht die hohe Zahl von Patienten, die auch nach Koronarintervention weiter Angina pectoris haben.

FT4/FT3 ratio: A novel biomarker predicts coronary microvascular dysfunction (CMD) in euthyroid INOCA patients

BACKGROUND

Ischemia and no obstructive coronary artery disease (INOCA) patients who presented coronary microvascular dysfunction (CMD) demonstrate a poor prognosis, yet the risk factors for CMD remain unclear. Subtle changes in thyroid hormone levels within the normal range, especially the free thyroxine (FT4)/free triiodothyronine (FT3) ratio, have been shown to regulate the cardiovascular system. This prospective study investigated the correlation between FT4/FT3 ratio and CMD in euthyroid patients with INOCA.

METHODS

This prospective study (www.chictr.org.cn/, ChiCTR2000037112) recruited patients with myocardial ischemia symptoms who underwent both coronary angiography (CAG) and myocardial perfusion imaging (MPI) with dynamic single-photon emission computed tomography (D-SPECT). INOCA was defined as coronary stenosis< 50% and CMD was defined as coronary flow reserve (CFR)<2.5. All patients were excluded from abnormal thyroid function and thyroid disease history.

RESULTS

Among 71 INOCA patients (15 [21.1%] CMD), FT4 and FT4/FT3 ratio in CMD group were significantly higher and both showed significantly moderate correlation with CFR (r=-0.25, p=0.03; r=-0.34, p=0.003, respectively). The ROC curve revealed that FT4/FT3 ratio had the highest efficacy for predicting CMD with an optimized cutoff value>3.39 (AUC 0.78, p<0.001, sensitivity, 80.0%; specificity, 71.4%). Multivariate logistic regression showed that FT4/FT3 ratio was an independent predictor of CMD (OR 7.62, 95% CI 1.12-51.89, p=0.038, P for trend=0.006).

CONCLUSION

In euthyroid INOCA patients, increased FT4/FT3 ratio levels are associated with the occurrence of CMD, presenting a novel biomarker for improving the risk stratification.

Definitions and Epidemiology of Coronary Functional Abnormalities

Coronary functional abnormalities are frequent causes of angina pectoris, particularly in patients with unobstructed coronary arteries. There is a spectrum of endotypes of functional coronary abnormalities with different mechanisms of pathology including enhanced vasoconstriction (i.e. coronary artery spasm) or impaired vasodilatation, such as impaired coronary flow reserve or increased microvascular resistance. These vasomotor abnormalities can affect various compartments of the coronary circulation such as the epicardial conduit arteries and/or the coronary microcirculation. Unequivocal categorisation and nomenclature of the broad spectrum of disease endotypes is crucial both in clinical practice as well as in clinical trials. This article describes the definitions of coronary functional abnormalities with currently accepted cut-off values, as well as diagnostic methods to identify and distinguish endotypes. The authors also provide a summary of contemporary data on the prevalence of the different endotypes of coronary functional abnormalities and their coexistence.

Pathophysiology of Coronary Microvascular Dysfunction

Ischemic heart disease (IHD) is commonly recognized as the consequence of coronary atherosclerosis and obstructive coronary artery disease (CAD). However, a significant number of patients may present angina or myocardial infarction even in the absence of any significant coronary artery stenosis and impairment of the coronary microcirculation has been increasingly implicated as a relevant cause of IHD. The term "coronary microvascular dysfunction" (CMD) encompasses several pathogenic mechanisms resulting in functional and/or structural changes in the coronary microcirculation and determining angina and myocardial ischemia in patients with angina without obstructive CAD ("primary" microvascular angina), as well as in several other conditions, including obstructive CAD, cardiomyopathies, Takotsubo syndrome and heart failure, especially the phenotype with preserved ejection fraction. The pathogenesis of CMD is complex and involves the combination of functional and structural alterations leading to impaired coronary blood flow and resulting in myocardial ischemia. In the absence of therapies specifically targeting CMD, attention has been focused on the role of modifiable risk factors. Here, we provide updated evidence regarding the pathophysiological mechanisms underlying CMD, with a particular focus on the role of cardiovascular risk factors and comorbidities. Moreover, we discuss the specific pathogenic mechanisms of CMD across the different cardiovascular diseases, aiming to pave the way for further research and the development of novel strategies for a precision medicine approach.

Doppler Echocardiography Assessment of Coronary Microvascular Function in Patients With Angina and No Obstructive Coronary Artery Disease

Echocardiographic evaluation is an essential part of the diagnostic work-up in patients with known or suspected cardiovascular disease. Transthoracic Doppler echocardiography (TTDE) enables straightforward and reliable visualization of flow in the left anterior descending artery. In the absence of obstructive coronary artery disease, low TTDE-derived coronary flow velocity reserve (CFVR) is considered a marker of coronary microvascular dysfunction (CMD). TTDE CFVR is free from ionizing radiation and widely available, utilizing high-frequency transducers, pharmacologic vasodilator stress, and pulsed-wave Doppler quantification of diastolic peak flow velocities. European Society of Cardiology guidelines recommend TTDE CFVR evaluation only following preceding anatomic invasive or non-invasive coronary imaging excluding obstructive CAD. Accordingly, clinical use of TTDE CFVR is limited and CMD frequently goes undiagnosed. An evolving body of evidence underlines that low CFVR is an important and robust predictor of adverse prognosis and continuing symptoms in angina patients both with and without obstructive CAD. The majority of angina patients have no obstructive CAD, particularly among women. This has led to the suggestion that there may be a gender-specific female atherosclerotic phenotype with less epicardial obstruction, and a low CFVR signifying CMD instead. Nevertheless, available evidence indicates low CFVR is an equally important prognostic marker in both men and women. In this review, TTDE CFVR was evaluated regarding indication, practical and technical aspects, and interpretation of results. Association with symptoms and prognosis, comparison with alternative invasive and non-invasive imaging modalities, and possible interventions in angina patients with low CFVR were discussed, and key research questions were proposed.

Pathophysiology and Diagnosis of Coronary Functional Abnormalities

Approximately one-half of patients undergoing diagnostic coronary angiography for angina have no significant coronary atherosclerotic stenosis. This clinical condition has recently been described as ischaemia with non-obstructive coronary arteries (INOCA). Coronary functional abnormalities are central to the pathogenesis of INOCA, including epicardial coronary spasm and coronary microvascular dysfunction composed of a variable combination of increased vasoconstrictive reactivity and/or reduced vasodilator function. During the last decade - in INOCA patients in particular - evidence for the prognostic impact of coronary functional abnormalities has accumulated and various non-invasive and invasive diagnostic techniques have enabled the evaluation of coronary vasomotor function in a comprehensive manner. In this review, the authors briefly summarise the recent advances in the understanding of pathophysiology and diagnosis of epicardial coronary artery spasm and coronary microvascular dysfunction.

Functional Assessment of Coronary Artery Disease by Myocardial Flow Reserve Versus Pressure-wire Based Assessment

Positron emission tomography (PET) permits the noninvasive quantification of myocardial blood flow (MBF). Myocardial flow reserve (MFR), calculated by dividing stress MBF by rest MBF is a reliable index for the functional information of coronary artery disease. A pressure-derived physiological index, such as fractional flow reserve (FFR) is also an important measurement. Both MFR and FFR values are used to evaluate coronary physiology; however, but they are not interchangeable because each test has certain discrepancies. In this systematic review, we provide an overview of coronary physiology with PET compared to pressure-derived physiological indices.

Reduced nitric oxide bioavailability impairs myocardial oxygen balance during exercise in swine with multiple risk factors

In the present study, we tested the hypothesis that multiple risk factors, including diabetes mellitus (DM), dyslipidaemia and chronic kidney disease (CKD) result in a loss of nitric oxide (NO) signalling, thereby contributing to coronary microvascular dysfunction. Risk factors were induced in 12 female swine by intravenous streptozotocin injections (DM), a high fat diet (HFD) and renal artery embolization (CKD). Female healthy swine (n = 13) on normal diet served as controls (Normal). After 5 months, swine were chronically instrumented and studied at rest and during exercise. DM + HFD + CKD swine demonstrated significant hyperglycaemia, dyslipidaemia and impaired kidney function compared to Normal swine. These risk factors were accompanied by coronary microvascular endothelial dysfunction both in vivo and in isolated small arteries, due to a reduced NO bioavailability, associated with perturbations in myocardial oxygen balance at rest and during exercise. NO synthase inhibition caused coronary microvascular constriction in exercising Normal swine, but had no effect in DM + HFD + CKD animals, while inhibition of phosphodiesterase 5 produced similar vasodilator responses in both groups, indicating that loss of NO bioavailability was principally responsible for the observed coronary microvascular dysfunction. This was associated with an increase in myocardial 8-isoprostane levels and a decrease in antioxidant capacity, while antioxidants restored the vasodilation to bradykinin in isolated coronary small arteries, suggesting that oxidative stress was principally responsible for the reduced NO bioavailability. In conclusion, five months of combined exposure to DM + HFD + CKD produces coronary endothelial dysfunction due to impaired NO bioavailability, resulting in impaired myocardial perfusion at rest and during exercise.

Smoking, alcohol and opioids effect on coronary microcirculation: an update overview

Smoking, heavy alcohol drinking and drug abuse are detrimental lifestyle factors leading to loss of million years of healthy life annually. One of the major health complications caused by these substances is the development of cardiovascular diseases (CVD), which accounts for a significant proportion of substance-induced death. Smoking and excessive alcohol consumption are related to the higher risk of acute myocardial infarction. Similarly, opioid addiction, as one of the most commonly used substances worldwide, is associated with cardiac events such as ischemia and myocardial infarction (MI). As supported by many studies, coronary artery disease (CAD) is considered as a major cause for substance-induced cardiac events. Nonetheless, over the last three decades, a growing body of evidence indicates that a significant proportion of substance-induced cardiac ischemia or MI cases, do not manifest any signs of CAD. In the absence of CAD, the coronary microvascular dysfunction is believed to be the main underlying reason for CVD. To date, comprehensive literature reviews have been published on the clinicopathology of CAD caused by smoking and opioids, as well as macrovascular pathological features of the alcoholic cardiomyopathy. However, to the best of our knowledge there is no review article about the impact of these substances on the coronary microvascular network. Therefore, the present review will focus on the current understanding of the pathophysiological alterations in the coronary microcirculation triggered by smoking, alcohol and opioids.

Coronary Microvascular Dysfunction

Many patients with chest pain undergoing coronary angiography do not show significant obstructive coronary lesions. A substantial proportion of these patients have abnormalities in the function and structure of coronary microcirculation due to endothelial and smooth muscle cell dysfunction. The coronary microcirculation has a fundamental role in the regulation of coronary blood flow in response to cardiac oxygen requirements. Impairment of this mechanism, defined as coronary microvascular dysfunction (CMD), carries an increased risk of adverse cardiovascular clinical outcomes. Coronary endothelial dysfunction accounts for approximately two-thirds of clinical conditions presenting with symptoms and signs of myocardial ischemia without obstructive coronary disease, termed "ischemia with non-obstructive coronary artery disease" (INOCA) and for a small proportion of "myocardial infarction with non-obstructive coronary artery disease" (MINOCA). More frequently, the clinical presentation of INOCA is microvascular angina due to CMD, while some patients present vasospastic angina due to epicardial spasm, and mixed epicardial and microvascular forms. CMD may be associated with focal and diffuse epicardial coronary atherosclerosis, which may reinforce each other. Both INOCA and MINOCA are more common in females. Clinical classification of CMD includes the association with conditions in which atherosclerosis has limited relevance, with non-obstructive atherosclerosis, and with obstructive atherosclerosis. Several studies already exist which support the evidence that CMD is part of systemic microvascular disease involving multiple organs, such as brain and kidney. Moreover, CMD is strongly associated with the development of heart failure with preserved ejection fraction (HFpEF), diabetes, hypertensive heart disease, and also chronic inflammatory and autoimmune diseases. Since coronary microcirculation is not visible on invasive angiography or computed tomographic coronary angiography (CTCA), the diagnosis of CMD is usually based on functional assessment of microcirculation, which can be performed by both invasive and non-invasive methods, including the assessment of delayed flow of contrast during angiography, measurement of coronary flow reserve (CFR) and index of microvascular resistance (IMR), evaluation of angina induced by intracoronary acetylcholine infusion, and assessment of myocardial perfusion by positron emission tomography (PET) and magnetic resonance (CMR).

Assessment of Vascular Dysfunction in Patients Without Obstructive Coronary Artery Disease: Why, How, and When

Ischemic heart disease secondary to coronary vascular dysfunction causes angina and impairs quality of life and prognosis. About one-half of patients with symptoms and signs of ischemia turn out not to have obstructive coronary artery disease, and coronary vascular dysfunction may be relevant. Adjunctive tests of coronary vasomotion include guidewire-based techniques with adenosine and reactivity testing, typically by intracoronary infusion of acetylcholine. The CorMicA (Coronary Microvascular Angina) trial provided evidence that routine management guided by an interventional diagnostic procedure and stratified therapy improves angina and quality of life in patients with angina but no obstructive coronary artery disease. In this paper, the COVADIS study group provide a comprehensive review of why, how, and when coronary vascular dysfunction should be assessed invasively. They discuss the rationale through a shared understanding of vascular pathophysiology and clinical evidence. They propose a consensus approach to how an interventional diagnostic procedure is performed with focus on practical aspects. Finally, the authors discuss the clinical scenarios in patients with stable and acute coronary syndromes in which measurement of coronary vascular function may be helpful for patient care.

Overview of Quantitative Flow Ratio and Optical Flow Ratio in the Assessment of Intermediate Coronary Lesions

Fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) improves clinical outcome compared with angiography-guided PCI. Advances in computational technology have resulted in the development of solutions, enabling fast derivation of FFR from imaging data in the catheterization laboratory. The quantitative flow ratio is currently the most validated approach to derive FFR from invasive coronary angiography, while the optical flow ratio allows faster and more automation in FFR computation from intracoronary optical coherence tomography. The use of quantitative flow ratio and optical flow ratio has the potential for swift and safe identification of lesions that require revascularization, optimization of PCI, evaluation of plaque features, and virtual planning of PCI.

Microvascular disease confers additional risk to COVID-19 infection

The majority of fatalities thus far in the COVID-19 pandemic have been attributed to pneumonia. As expected, the fatality rate reported in China is higher in people with chronic pulmonary disease (6.3%) and those who have cancer (5.6%). According to the American College of Cardiology Clinical Bulletin "COVID-19 Clinical Guidance for the CV Care Team", there is a significantly higher fatality rate in people who are elderly (8.0% 70-79 years; 14.8% ≥80 years), diabetic (7.3%), hypertensive (6.0%), or have known cardiovascular disease (CVD) (10.5%). We propose a biological reason for the higher mortality risk in these populations that is apparent. We further present a set of pathophysiological reasons for the heightened danger that could lead to therapies for enhanced management and prevention.