Reappraisal of Ischemic Heart Disease

Innervation of the coronary arteries and its role in controlling microvascular resistance

The coronary circulation plays a crucial role in balancing myocardial perfusion and oxygen demand to prevent myocardial ischemia. Extravascular compressive forces, coronary perfusion pressure, and microvascular resistance are involved to regulate coronary blood flow throughout the cardiac cycle. Autoregulation of the coronary blood flow through dynamic adjustment of microvascular resistance is maintained by complex interactions among mechanical, endothelial, metabolic, neural, and hormonal mechanisms. This review focuses on the neural mechanism. Anatomy and physiology of the coronary arterial innervation have been extensively investigated using animal models. However, findings in the animal heart have limited applicability to the human heart as cardiac innervation is generally highly variable among species. So far, limited data are available on the human coronary artery innervation, rendering multiple questions unresolved. Recently, the clinical entity of ischemia with non-obstructive coronary arteries has been proposed, characterized by microvascular dysfunction involving abnormal vasoconstriction and impaired vasodilation. Thus, measurement of microvascular resistance has become a standard diagnostic for patients without significant stenosis in the epicardial coronary arteries. Neural mechanism is likely to play a pivotal role, supported by the efficacy of cardiac sympathetic denervation to control symptoms in patients with angina. Therefore, understanding the coronary artery innervation and control of microvascular resistance of the human heart is increasingly important for cardiologists for diagnosis and to select appropriate therapeutic options. Advancement in this field can lead to innovations in diagnostic and therapeutic approaches for coronary artery diseases.

Stratified medicine for acute and chronic coronary syndromes: A patient-tailored approach

The traditional approach to management of cardiovascular disease relies on grouping clinical presentations with common signs and symptoms into pre-specified disease pathways, all uniformly treated according to evidence-based guidelines ("one-size-fits-all"). The goal of precision medicine is to provide the right treatment to the right patients at the right time, combining data from time honoured sources (e.g., history, physical examination, imaging, laboratory) and those provided by multi-omics technologies. In patients with ischemic heart disease, biomarkers and intravascular assessment can be used to identify endotypes with different pathophysiology who may benefit from distinct treatments. This review discusses strategies for the application of stratified management to patients with acute and chronic coronary syndromes.

New avenues for the assessment of stable ischemic heart disease

Myocardial ischemia is a complex condition which may result from epicardial and/or microvascular causes involving functional and structural mechanisms. These mechanisms may overlap in a given patient illustrating the difficulties for appropriate management. Assessment of myocardial ischemia can be performed using noninvasive and invasive tools. However, despite living in the era of individualized precision medicine, these tools are not yet used in a broader fashion. Emerging noninvasive techniques such as quantitative perfusion cardiac magnetic resonance imaging (CMR) and stress perfusion computed tomography (CT) or photon-counting CT techniques may contribute to new standards in the assessment of stable angina patients. Invasive evaluation of myocardial ischemia should not only focus on hemodynamically relevant epicardial disease but also involve coronary vasomotor function testing (coronary spasm, coronary flow reserve, and microvascular resistance) where appropriate. Optimal patient management will depend on accurate and comprehensive diagnostic evaluation of myocardial ischemia and development of new treatment options in the future.

Angina pectoris 2023: With and without obstructive coronary artery disease: Epidemiology, diagnosis, prognosis, and treatment

Angina contributes to significant morbidity worldwide. The evaluation of angina is variable and complicated by multiple factors. The diagnosis is often focussed on epicardial disease despite the knowledge that chest pain can be due to cardiac, non-cardiac, macro, and microvascular causes. Standardised diagnostic pathways and novel approaches to angina assessment may offer the opportunity to improve our understanding of angina and apply a personalised approach to treatment.

GSEA analysis identifies potential drug targets and their interaction networks in coronary microcirculation disorders

Coronary microcirculation dysfunction (CMD) is one of the main causes of cardiovascular disease. Traditional treatment methods lack specificity, making it difficult to fully consider the differences in patient conditions and achieve effective treatment and intervention. The complexity and diversity of CMD require more standardized diagnosis and treatment plans to clarify the best treatment strategy and long-term outcomes. The existing treatment measures mainly focus on symptom management, including medication treatment, lifestyle intervention, and psychological therapy. However, the efficacy of these methods is not consistent for all patients, and the long-term efficacy is not yet clear. GSEA is a bioinformatics method used to interpret gene expression data, particularly for identifying the enrichment of predefined gene sets in gene expression data. In order to achieve personalized treatment and improve the quality and effectiveness of interventions, this article combined GSEA (Gene Set Enrichment Analysis) technology to conduct in-depth research on potential drug targets and their interaction networks in coronary microcirculation dysfunctions. This article first utilized the Coremine medical database, GeneCards, and DrugBank public databases to collect gene data. Then, filtering methods were used to preprocess the data, and GSEA was used to analyze the preprocessed gene expression data to identify and calculate pathways and enrichment scores related to CMD. Finally, protein sequence features were extracted through the calculation of autocorrelation features. To verify the effectiveness of GSEA, this article conducted experimental analysis from four aspects: precision, receiver operating characteristic (ROC) curve, correlation, and potential drug targets, and compared them with Gene Regulatory Networks (GRN) and Random Forest (RF) methods. The results showed that compared to the GRN and RF methods, the average precision of GSEA improved by 0.11. The conclusion indicated that GSEA helped identify and explore potential drug targets and their interaction networks, providing new ideas for personalized quality of CMD.

Transcriptomic and spatial dissection of human ex vivo right atrial tissue reveals proinflammatory microvascular changes in ischemic heart disease

Cardiovascular disease plays a central role in the electrical and structural remodeling of the right atrium, predisposing to arrhythmias, heart failure, and sudden death. Here, we dissect with single-nuclei RNA sequencing (snRNA-seq) and spatial transcriptomics the gene expression changes in the human ex vivo right atrial tissue and pericardial fluid in ischemic heart disease, myocardial infarction, and ischemic and non-ischemic heart failure using asymptomatic patients with valvular disease who undergo preventive surgery as the control group. We reveal substantial differences in disease-associated gene expression in all cell types, collectively suggesting inflammatory microvascular dysfunction and changes in the right atrial tissue composition as the valvular and vascular diseases progress into heart failure. The data collectively suggest that investigation of human cardiovascular disease should expand to all functionally important parts of the heart, which may help us to identify mechanisms promoting more severe types of the disease.

Impact of Coronary Microvascular Dysfunction on Functional Left Ventricular Remodeling and Diastolic Dysfunction

BACKGROUND

Coronary microvascular dysfunction (CMD) is a common complication of ST-segment-elevation myocardial infarction (STEMI) and can lead to adverse cardiovascular events. Whether CMD after STEMI is associated with functional left ventricular remodeling (FLVR) and diastolic dysfunction, has not been investigated.

METHODS AND RESULTS

This is a nonrandomized, observational, prospective study of patients with STEMI with multivessel disease. Coronary flow reserve and index of microcirculatory resistance of the culprit vessel were measured at 3 months post-STEMI. CMD was defined as index of microcirculatory resistance ≥25 or coronary flow reserve <2.0 with a normal fractional flow reserve. We examined the association between CMD, LV diastolic dysfunction, FLVR, and major adverse cardiac events at 12-month follow-up. A total of 210 patients were enrolled; 59.5% were men, with a median age of 65 (interquartile range, 58-76) years. At 3-month follow-up, 57 patients (27.14%) exhibited CMD. After 12 months, when compared with patients without CMD, patients with CMD had poorer LV systolic function recovery (-10.00% versus 8.00%; P<0.001), higher prevalence of grade 2 LV diastolic dysfunction (73.08% versus 1.32%; P<0.001), higher prevalence of group 3 or 4 FLVR (11.32% versus 7.28% and 22.64% versus 1.99%, respectively; P<0.001), and higher incidence of major adverse cardiac events (50.9% versus 9.8%; P<0.001). Index of microcirculatory resistance was independently associated with LV diastolic dysfunction and adverse FLVR.

CONCLUSIONS

CMD is present in ≈1 of 4 patients with STEMI during follow-up. Patients with CMD have a higher prevalence of LV diastolic dysfunction, adverse FLVR, and major adverse cardiac events at 12 months compared with those without CMD.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique Identifier: NCT05406297.

Differentiating Macrovascular and Microvascular Ischemia Using Fractal Analysis of Dynamic Myocardial Perfusion Stress-CT

OBJECTIVES

Fractal analysis of dynamic myocardial stress computed tomography perfusion imaging (4D-CTP) has shown potential to noninvasively differentiate obstructive coronary artery disease (CAD) and coronary microvascular disease (CMD). This study validates fractal analysis of 4D-CTP in a multicenter setting and assesses its diagnostic accuracy in subgroups with ischemia and nonobstructed coronary arteries (INOCA) and with mild to moderate stenosis.

MATERIALS AND METHODS

From the AMPLIFiED multicenter trial, patients with suspected or known chronic myocardial ischemia and an indication for invasive coronary angiography were included. Patients underwent dual-source CT angiography, 4D-CTP, and CT delayed-enhancement imaging. Coronary artery disease, CMD, and normal perfusion were defined by a combined reference standard comprising invasive coronary angiography with fractional flow reserve, and absolute or relative CT-derived myocardial blood flow. Nonobstructed coronary arteries were defined as ≤25% stenosis and mild to moderate stenosis as 26%-80%.

RESULTS

In 127 patients (27% female), fractal analysis accurately differentiated CAD (n = 61, 23% female), CMD (n = 23, 30% female), and normal perfusion (n = 34, 35% female) with a multiclass area under the receiver operating characteristic curve (AUC) of 0.92 and high agreement (multiclass κ = 0.89). In patients with ischemia (n = 84), fractal analysis detected CAD (n = 61) over CMD (n = 23) with sensitivity of 95%, specificity of 74%, accuracy of 89%, and AUC of 0.83. In patients with nonobstructed coronary arteries (n = 33), INOCA (n = 15) was detected with sensitivity of 100%, specificity of 78%, accuracy of 88%, and AUC of 0.94. In patients with mild to moderate stenosis (n = 27), fractal analysis detected CAD (n = 19) over CMD with sensitivity of 84%, specificity of 100%, accuracy of 89%, and AUC of 0.95.

CONCLUSIONS

In this multicenter study, fractal analysis of 4D-CTP accurately differentiated CAD and CMD including subgroups with INOCA and with mild to moderate stenosis.

[Angina and no obstruction on coronary angiography : New approaches to the diagnosis and treatment of vasomotor disorders]

BACKGROUND

Clinical management of patients with angina and no obstructive coronary artery disease (ANOCA) is still challenging. This scenario affects up to 50% of patients undergoing diagnostic coronary angiography due to suspected coronary artery disease. Many patients report a long and debilitating history before adequate diagnostics and management are initiated.

OBJECTIVES

This article describes the current recommendations for diagnostic assessments and treatment in patients with ANOCA. Focus is placed on invasive diagnostics in the catheter laboratory, pharmacological/interventional treatment as well as the patient journey.

RESULTS

In patients with ANOCA, the current European Society of Cardiology (ESC) guidelines suggest that invasive assessments using acetylcholine and adenosine for the diagnosis of an underlying coronary vasomotor disorder should be considered. Acetylcholine is used to diagnose coronary spasm, whereas adenosine is used in conjunction with a wire-based assessment for the measurement of coronary flow reserve and microvascular resistance. The invasive assessments allow the determination of what are referred to as endotypes (coronary spasm, impaired coronary flow reserve, enhanced microvascular resistance or a combination thereof). Establishing a diagnosis is helpful to: (a) initiate targeted treatment to improve quality of life, (b) reassure the patient that a cardiac cause is found and (c) to assess individual prognosis.

CONCLUSIONS

Currently, patients with ANOCA are often not adequately managed. Referral to specialised centres is recommended to prevent long and debilitating patient histories until expertise in diagnosis and treatment becomes more widespread.

Serum SERCA2a levels in heart failure patients are associated with adverse events after discharge

Calcium homeostasis imbalance is one of the important pathological mechanisms in heart failure. Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2a), a calcium ATPase on the sarcoplasmic reticulum in cardiac myocytes, is a myocardial systolic-diastolic Ca2 + homeostasis regulating enzyme that is not only involved in cardiac diastole but also indirectly affects cardiac myocyte contraction. SERCA2a expression was found to be decreased in myocardial tissue in heart failure, however, there are few reports on serum SERCA2a expression in patients with heart failure, and this study was designed to investigate whether serum SERCA2a levels are associated with the occurrence of adverse events after discharge in patients hospitalized with heart failure. Patients with heart failure hospitalized in the cardiovascular department of the Second Affiliated Hospital of Guangdong Medical University, China, from July 2018 to July 2019 were included in this study, and serum SERCA2a concentrations were measured; each enrolled patient was followed up by telephone after 6 months (6 ± 1 months) for general post-discharge patient status. The correlation between serum SERCA2a levels and the occurrence of adverse events (death or readmission due to heart failure) after hospital discharge was assessed using multiple analysis and trend analysis. Seventy-one patients with heart failure were finally included in this study, of whom 38 (53.5%) were men and 33 (46.5%) were women (All were postmenopausal women). Multiple analysis revealed no correlation between serum SERCA2a levels and the occurrence of adverse events in the total study population and in male patients, but serum SERCA2a levels were associated with the occurrence of adverse outcome events after hospital discharge in female patients (OR = 1.02, P = .047). Further analysis using a trend analysis yielded a 4.0% increase in the risk of adverse outcomes after hospital discharge for each unit increase in SERCA2a in female patients (OR = 1.04; P = .02), while no significant difference was seen in men. This study suggests that serum SERCA2a levels at admission are associated with the occurrence of post-discharge adverse events in postmenopausal female patients hospitalized with heart failure.

Dapagliflozin ameliorates myocardial infarction injury through AMPKα-dependent regulation of oxidative stress and apoptosis

Dapagliflozin (DAPA) has been demonstrated to reduce cardiovascular mortality and heart failure hospitalization rates in diabetic patients. However, the mechanism underlying its cardio-protective effect in non-diabetic patients remains unclear. Our study aimed to explore the cardio-protective impact of DAPA on myocardial infarction in non-diabetic mice. We induced myocardial infarction in C57BL/6 mice by ligating the descending branch of the left coronary artery. After surgery, the animals were randomly treated with either saline or DAPA. We employed echocardiography, Western blot analysis, and tissue staining to assess post-infarction myocardial injury. Additionally, we investigated the mechanism of action through cell experiments. Compared to the myocardial infarction group, DAPA treatment significantly attenuated ventricular remodeling and improved cardiac function. By mitigating myocardial oxidative stress and apoptosis, DAPA may activate the AMPKα signaling pathway, thereby exerting a protective effect. These findings suggest that DAPA could serve as a novel therapeutic approach for patients with cardiac infarction.

Phosphorylated CPI-17 and MLC2 as Biomarkers of Coronary Artery Spasm-Induced Sudden Cardiac Death

Coronary artery spasm (CAS) plays an important role in the pathogeneses of various ischemic heart diseases and has gradually become a common cause of life-threatening arrhythmia. The specific molecular mechanism of CAS has not been fully elucidated, nor are there any specific diagnostic markers for the condition. Therefore, this study aimed to examine the specific molecular mechanism underlying CAS, and screen for potential diagnostic markers. To this end, we successfully constructed a rat CAS model and achieved in vitro culture of a human coronary-artery smooth-muscle cell (hCASMC) contraction model. Possible molecular mechanisms by which protein kinase C (PKC) regulated CAS through the C kinase-potentiated protein phosphatase 1 inhibitor of 17 kDa (CPI-17)/myosin II regulatory light chain (MLC2) pathway were studied in vivo and in vitro to screen for potential molecular markers of CAS. We performed hematoxylin and eosin staining, myocardial zymogram, and transmission electron microscopy to determine myocardial and coronary artery injury in CAS rats. Then, using immunohistochemical staining, immunofluorescence staining, and Western blotting, we further demonstrated a potential molecular mechanism by which PKC regulated CAS via the CPI-17/MLC2 pathway. The results showed that membrane translocation of PKCα occurred in the coronary arteries of CAS rats. CPI-17/MLC2 signaling was observably activated in coronary arteries undergoing CAS. In addition, in vitro treatment of hCASMCs with angiotensin II (Ang II) increased PKCα membrane translocation while consistently activating CPI-17/MLC2 signaling. Conversely, GF-109203X and calphostin C, specific inhibitors of PKC, inactivated CPI-17/MLC2 signaling. We also collected the coronary artery tissues from deceased subjects suspected to have died of CAS and measured their levels of phosphorylated CPI-17 (p-CPI-17) and MLC2 (p-MLC2). Immunohistochemical staining was positive for p-CPI-17 and p-MLC2 in the tissues of these subjects. These findings suggest that PKCα induced CAS through the CPI-17/MLC2 pathway; therefore, p-CPI-17 and p-MLC2 could be used as potential markers for CAS. Our data provide novel evidence that therapeutic strategies against PKC or CPI-17/MLC2 signaling might be promising in the treatment of CAS.

Coronary Artery Disease Assessment and Cardiovascular Events in Middle-Aged Patients on Hemodialysis

OBJECTIVE

To explore whether, in younger patients on dialysis with longer life expectancy, assessment of coronary artery disease (CAD) could identify individuals at higher risk of events and revascularization might improve outcomes in selected patients contrary to what had been observed in elderly patients.

METHODS

From August 1997 to January 2019, 2265 patients with stage 5 chronic kidney disease were prospectively referred for cardiovascular assessment. For this study, we selected 1374 asymptomatic patients aged between 18 and 64 years. After clinical risk stratification and cardiac scintigraphy by single-photon emission computed tomography, 866 patients underwent coronary angiography. The primary end point was the composite incidence of nonfatal/fatal major adverse cardiovascular events during a follow-up period of 0.1 to 189.7 months (median, 26 months). The secondary end point was all-cause mortality.

RESULTS

The primary end point occurred in 327 (23.8%) patients. Clinically stratified high-risk patients had a 3-fold increased risk of the primary end point. The prevalence of abnormal findings on perfusion scans was 29.2% (n=375), and significant CAD was found in 449 (51.8%) of 866 patients who underwent coronary angiography. An abnormal finding on myocardial perfusion scan and the presence of CAD were significantly associated with a 74% and 22% increased risk of cardiovascular events, respectively. In patients undergoing percutaneous coronary intervention or coronary artery bypass grafting (n=99), there was an 18% reduction in the risk of all-cause death relative to patients receiving medical treatment (P=.03).

CONCLUSION

In this cohort of middle-aged, asymptomatic patients on dialysis, assessment of CAD identified individuals at higher risk of events, and coronary intervention was associated with reducing the risk of death in selected patients.

Impacts of systemic inflammation response index on the prognosis of patients with ischemic heart failure after percutaneous coronary intervention

Background

Atherosclerosis and cardiovascular diseases are significantly affected by low-grade chronic inflammation. As a new inflammatory marker, the systemic inflammation response index (SIRI) has been demonstrated to be associated with several cardiovascular disease prognoses. This study aimed to investigate the prognostic impact of SIRI in individuals having ischemic heart failure (IHF) following percutaneous coronary intervention (PCI).

Methods

This observational, retrospective cohort study was conducted at a single site. Finally, the research involved 1,963 individuals with IHF who underwent PCI, with a 36-month follow-up duration. Based on the SIRI quartiles, all patients were classified into four groups. Major adverse cardiovascular events (MACEs) were the primary outcomes. Every element of the main endpoint appeared in the secondary endpoints: all-cause mortality, non-fatal myocardial infarction (MI), and any revascularization. Kaplan-Meier survival analysis was conducted to assess the incidence of endpoints across the four groups. Multivariate Cox proportional hazards analysis confirmed the independent impact of SIRI on both the primary and secondary endpoints. The restricted cubic spline (RCS) was used to assess the nonlinear association between the SIRI and endpoints. Subgroup analysis was performed to confirm the implications of SIRI on MACE in the different subgroups.

Results

The main outcome was much more common in patients with a higher SIRI. The Kaplan-Meier curve was another tool that was used to confirm the favorable connection between SIRI and MACE. SIRI was individually connected to a higher chance of the main outcome according to multivariate analyses, whether or not SIRI was a constant [SIRI, per one-unit increase, hazard ratio (HR) 1.04, 95% confidence interval (95% CI) 1.01-1.07, p = 0.003] or categorical variable [quartile of SIRI, the HR (95% CI) values for quartile 4 were 1.88 (1.47-2.42), p <0.001, with quartile 1 as a reference]. RCS demonstrated that the hazard of the primary and secondary endpoints generally increased as SIRI increased. A non-linear association of SIRI with the risk of MACE and any revascularization (Non-linear P <0.001) was observed. Subgroup analysis confirmed the increased risk of MACE with elevated SIRI in New York Heart Association (NYHA) class III-IV (P for interaction = 0.005).

Conclusion

In patients with IHF undergoing PCI, increased SIRI was a risk factor for MACE independent of other factors. SIRI may represent a novel, promising, and low-grade inflammatory marker for the prognosis of patients with IHF undergoing PCI.

The diagnosis and treatment of women with recurrent cardiac ischemia and normal coronary arteries

Cardiac disease is the leading cause of death in women. Among women with recurrent chest pain, abnormal electrocardiograms, and/or stress tests who undergo coronary angiography, as many as 50% have normal or <50% coronary artery obstructive disease. Pharmacologic stress assessment of coronary artery flow reserve in these women frequently demonstrates an inability to increase blood flow to >2.5 times normal flow. Contributory factors include abnormal epicardial or microvascular reactivity, microvascular remodeling or rarefaction, autonomic dysfunction, or coronary plaque rupture/erosion. Assessment is necessary of serum biomarkers and coronary artery flow reserve, fractional flow reserve, microvascular resistance, and epicardial/microvascular spasm. Aggressive treatment of women with positive tests is necessary because these women have an increased incidence of recurrent chest pain, repeated hospitalizations and coronary angiograms, and cardiac death.

Men with nonobstructive coronary disease have higher burden of ischemic heart disease detected by cardiopulmonary exercise test

BACKGROUND

Nonobstructive coronary artery disease (NOCAD), characterized by the presence of myocardial ischemic symptoms and signs without obstructive coronaries, is a common clinical condition, but it is less well understood. Few studies have analyzed the gender differences in inducible myocardial ischemia assessed by cardiopulmonary exercise test (CPET) in NOCAD.

METHODS

We conducted a study of 289 NOCAD patients (mean age 60, 56% women) with ischemic symptoms and confirmed ⫹50% coronaries stenoses by coronary angiography who underwent symptom-limited CPET. We assessed ischemic response using predicted % peak VO2 , O2 pulse trajectory, and exercise ECG test.

RESULTS

Men with NOCAD had significantly lower predicted % peak VO2 (62% vs. 73%), higher proportions of flattening pattern (16% vs. 2%), and downward patterns of O2 pulse trajectory (2% vs. 0%) (p < .0001) compared with women. In contrast, women with NOCAD had a higher prevalence of shallow patterns of O2 pulse trajectory (21% vs. 6%, p < .0001). Men with NOCAD had a higher risk ischemic profile (medium risk: 63% vs. 54%, high risk: 18% vs. 4%, p < .0001). After adjustment, men with NOCAD had significantly lower predicted % peak VO2 (β -27.4, 95% CI -30.74 to -24.07), higher risk for abnormal O2 pulse trajectories (OR 4.21, 95% CI 1.93 to 9.19), and myocardial ischemia risk per CPET parameters (OR 3.14, 95% CI 1.78 to 5.54) (p < .0001).

CONCLUSION

Men with NOCAD had a higher risk profile for ischemic heart disease per CPET. Therefore, they should receive rigorous management and follow-up to prevent cardiovascular events.

Invasive Endotyping in Patients With Angina and No Obstructive Coronary Artery Disease: A Randomized Controlled Trial

BACKGROUND

We investigated the usefulness of invasive coronary function testing to diagnose the cause of angina in patients with no obstructive coronary arteries.

METHODS

Outpatients referred for coronary computed tomography angiography in 3 hospitals in the United Kingdom were prospectively screened. After coronary computed tomography angiography, patients with unobstructed coronary arteries, and who consented, underwent invasive endotyping. The diagnostic assessments included coronary angiography, fractional flow reserve (patient excluded if ≤0.80), and, for those without obstructive coronary artery disease, coronary flow reserve (abnormal <2.0), index of microvascular resistance (abnormal ≥25), and intracoronary infusion of acetylcholine (0.182, 1.82, and 18.2 μg/mL; 2 mL/min for 2 minutes) to assess for microvascular and coronary spasm. Participants were randomly assigned to disclosure of the results of the coronary function tests to the invasive cardiologist (intervention group) or nondisclosure (control group, blinded). In the control group, a diagnosis of vasomotor angina was based on medical history, noninvasive tests, and coronary angiography. The primary outcome was the between-group difference in the reclassification rate of the initial diagnosis on the basis of coronary computed tomography angiography versus the final diagnosis after invasive endotyping. The Seattle Angina Questionnaire summary score and Treatment Satisfaction Questionnaire for Medication were secondary outcomes.

RESULTS

Of 322 eligible patients, 250 (77.6%) underwent invasive endotyping; 19 (7.6%) had obstructive coronary disease, 127 (55.0%) had microvascular angina, 27 (11.7%) had vasospastic angina, 17 (7.4%) had both, and 60 (26.0%) had no abnormality. A total of 231 patients (mean age, 55.7 years; 64.5% women) were randomly assigned and followed up (median duration, 19.9 [12.6-26.9] months). The clinician diagnosed vasomotor angina in 51 (44.3%) patients in the intervention group and in 55 (47.4%) patients in the control group. After randomization, patients in the intervention group were 4-fold (odds ratio, 4.05 [95% CI, 2.32-7.24]; P<0.001) more likely to be diagnosed with a coronary vasomotor disorder; the frequency of this diagnosis increased to 76.5%. The frequency of normal coronary function (ie, no vasomotor disorder) was not different between the groups before randomization (51.3% versus 50.9%) but was reduced in the intervention group after randomization (23.5% versus 50.9%, P<0.001). At 6 and 12 months, the Seattle Angina Questionnaire summary score in the intervention versus control groups was 59.2±24.2 (2.3±16.2 change from baseline) versus 60.4±23.9 (4.6±16.4 change) and 63.7±23.5 (4.7±14.7 change) versus 66.0±19.3 (7.9±17.1 change), respectively, and not different between groups (global P=0.36). Compared with the control group, global treatment satisfaction was higher in the intervention group at 12 months (69.9±22.8 versus 61.7±26.9, P=0.013).

CONCLUSIONS

For patients with angina and no obstructive coronary arteries, a diagnosis informed by invasive functional assessment had no effect on long-term angina burden, whereas treatment satisfaction improved.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03477890.

Efficacy of Angiotensin-Converting Enzyme Inhibitors in Coronary Microvascular Dysfunction: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Coronary microvascular dysfunction (CMD) is becoming increasingly recognized as an important contributor to the development of ischemic heart diseases. Without obstructive coronary artery disease, the physiological function of the coronary microcirculation can be altered by structural, functional, and molecular factors, leading to myocardial ischemia. CMD can significantly impact the quality of life and prognosis and imposes a huge financial burden on healthcare systems and people. This meta-analysis aims to investigate the efficacy of angiotensin-converting enzyme inhibitors (ACEIs) for treating CMD. A systematic literature review identified randomized controlled trials (RCTs) comparing ACEIs with placebo in CMD patients. Review Manager, 5.3 for Windows, was utilized. Using the Mantel-Haenszel (M-H) method, improvement in coronary flow reserve (CFR) and systolic blood pressure events was pooled as mean difference (MD) in a meta-analysis model with a fixed effect model, whereas the number of chest pain episodes was pooled as MD with a random effect model. Five randomized controlled trials involving 209 patients were included in the analysis. The analysis demonstrated a statistically significant improvement in CFR in the ACEIs group compared to the placebo group (MD -0.3, 95% CI -0.61 to 0.01, P = 0.05). However, there was no significant difference in the number of chest pain episodes between the ACEIs and placebo groups (MD 1.79, 95% CI -3.99 to 7.58, P = 0.54). Similarly, no significant difference in blood pressure change was observed between the two groups (MD 4.02, 95% CI -3.25 to 11.28, P = 0.28). In conclusion, the appropriate treatment for CMD is a source of contention because adequate data is lacking. Our findings suggest that ACEIs may have a positive effect on improving CFR in patients with microvascular angina. However, ACEIs did not demonstrate a significant impact on the number of chest pain episodes or systolic blood pressure in this patient population. Further research, including RCTs with larger sample sizes and longer follow-up durations, is warranted to provide more conclusive evidence on the role of ACEIs in CMD management.

Invasive Assessment of Coronary Microcirculation: A State-of-the-Art Review

A significant proportion of patients presenting with signs and symptoms of myocardial ischemia have no "significant" epicardial disease; thereby, the assessment of coronary microcirculation gained an important role in improving diagnosis and guiding therapy. In fact, coronary microvascular dysfunction (CMD) could be found in a large proportion of these patients, supporting both symptoms and signs of myocardial ischemia. However, CMD represents a diagnostic challenge for two main reasons: (1) the small dimension of the coronary microvasculature prevents direct angiographic visualization, and (2) despite the availability of specific diagnostic tools, they remain invasive and underused in the current clinical practice. For these reasons, CMD remains underdiagnosed, and most of the patients remain with no specific treatment and quality-of-life-limiting symptoms. Of note, recent evidence suggests that a "full physiology" approach for the assessment of the whole coronary vasculature may offer a significant benefit in terms of symptom improvement among patients presenting with ischemia and non-obstructive coronary artery disease. We analyze the pathophysiology of coronary microvascular dysfunction, providing the readers with a guide for the invasive assessment of coronary microcirculation, together with the available evidence supporting its use in clinical practice.

Reassured on a background of vulnerability - people with microvascular angina 12 months after high-intensity physical exercise program

PURPOSE

Physical activity is recommended for patients with coronary microvascular dysfunction, however, avoided due to fear about the heart. The aim is to achieve an understanding of the meaning of physical activity one year after participating in a high-intensity exercise training program.

METHOD

Twelve people were interviewed using a phenomenological hermeneutic approach.

RESULTS

Four themes were formulated and revealed that one year after participating in high-intensity exercise training participants had an awareness of the meaning of the project, their chest pain and daily life: Being reassured, Daily life's impact on chest pain and continuing doing high-intensity exercise training, A strengthened body and mind, Being part of a group of people with similar problems.Comprehensive understanding was formulated as "Being reassured according being physically active in a background of vulnerability".

CONCLUSION

This study indicates that by going through the high-intensity exercise training program the person regains more unity with the lived body and an unfolding life. A person-centred approach is suggested including an underlying dimension of vulnerability. A lifeworld led care means meeting the patient in their way of relating to the world bodily and existentially. Taking this understanding into consideration will advance the requirements for establishing person-centred care.

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.

Off-pump vs. on-pump bypass surgery grafting in diabetic patients with three-vessel disease: a propensity score matching study

Background

Controversy exists regarding the advantages and risks of off-pump vs. on-pump coronary artery bypass grafting (CABG) for patients with diabetes. We therefore compare the early clinical outcomes of off-pump vs. on-pump procedures for diabetic patients with three-vessel disease.

Materials and methods

We conducted a retrospective analysis of clinical data obtained from 548 diabetic patients with three-vessel coronary artery disease who underwent isolated CABG between January 2016 and June 2020. To adjust the differences of baseline characteristics between the off-pump CABG (OPCAB) and on-pump CABG (ONCAB) groups, propensity score matching (PSM) was used. Following 1:1 matching, we selected 187 pairs of patients for further comparison of outcomes within the first 30 days after surgery.

Results

The preoperative characteristics of the patients between the two groups were clinically comparable after PSM. The OPCAB group exhibited a significantly higher incidence of incomplete revascularization (27.3% vs. 14.4%; P = 0.002) compared with the ONCAB group. No differences were seen in mortality within 30 days between the matched groups (1.1% vs. 3.7%; P = 0.174). Notably, the OPCAB group had a lower risk of respiratory failure or infection (2.1% vs. 7.0%; P = 0.025), less postoperative stroke (1.1% vs. 4.8%; P = 0.032), and reduced postoperative ventilator assistance time (35.8 ± 33.7 vs. 50.9 ± 64.8; P = 0.005).

Conclusion

OPCAB in diabetic patients with three-vessel disease is a safe procedure with reduced early stroke and respiratory complications and similar mortality rate, myocardial infarction, and renal failure requiring dialysis to conventional on-pump revascularization.

The impact of primary percutaneous coronary intervention strategies during ST-elevation myocardial infarction on the prevalence of coronary microvascular dysfunction

Coronary microvascular dysfunction (CMD) is a common complication of ST-segment elevation myocardial infarction (STEMI) and can lead to adverse cardiovascular events. This is a non-randomized, observational, prospective study of STEMI patients with multivessel disease who underwent primary PCI, grouped based on whether they underwent balloon pre-dilatation stenting or direct stenting of the culprit lesion. Coronary physiology measurements were performed 3 months post-PCI including coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) measurements at the culprit vessel. The primary endpoint was the prevalence of CMD at 3 months, defined as IMR ≥ 25 or CFR < 2.0 with a normal fractional flow reserve. Secondary endpoints included major adverse cardiovascular events (MACE) at 12 months. Two hundred ten patients were enrolled; most were men, 125 (59.5%), with a median age of 65 years. One hundred twelve (53.2%) underwent balloon pre-dilatation before stenting, and 98 (46.7%) underwent direct stenting. The prevalence of CMD at 3 months was lower in the direct stenting group than in the balloon pre-dilatation stenting group (12.24% vs. 40.18%; p < 0.001). Aspiration thrombectomy and administration of intracoronary glycoprotein IIb/IIIa inhibitors were associated with lower odds of CMD (OR = 0.175, p = 0.001 and OR = 0.113, p = 0.001, respectively). Notably, MACE in patients who underwent direct stenting was lower than in those who underwent balloon pre-dilatation before stenting (14.29% vs. 26.79%; p = 0.040). In STEMI patients with multivessel disease, direct stenting of the culprit lesion, aspiration thrombectomy and administration of intracoronary glycoprotein IIb/IIIa inhibitors were associated with a lower prevalence of CMD at 3 months and lower incidence of MACE at 12 months compared with balloon pre-dilatation stenting.This trial is registered at https://ichgcp.net/clinical-trials-registry/NCT05406297 .

Light-induced circadian rhythm disorder leads to microvascular dysfunction via up-regulating NETs

Circadian rhythm is a physical, mental, and behavioral pattern over the course of 24-hour cycle, and its disturbance is associated with increased risk of cardiovascular diseases. Microvascular dysfunction serves as an important cause of cardiovascular disease, but the relationship between rhythm disturbances and microcirculation remains elusive. Herein, we constructed the mice model of circadian rhythm disturbance and investigated the alterations of microvascular conditions. It was revealed that coronary microcirculatory function and cardiac diastolic function were significantly reduced, along with endothelium-dependent diastolic function of microvessels remarkably impaired in the rhythm-disordered group of mice compared to the control group. Notably, rhythm disturbance led to a significant upregulation of neutrophil extracellular traps (NETs) levels in mice, which cause endothelial dysfunction by inhibiting microvascular endothelial cell activity and migration capacity as well as inducing apoptosis. Additionally, intraperitoneal injection of Cl-amidine suppressed the production of NETs, which further improved coronary microcirculatory function and endothelium-dependent diastolic function. In conclusion, this study demonstrated that circadian rhythm disorders could induce the development of coronary microvascular dysfunction (CMD) through the up-regulation of NETs, providing a potential therapeutic direction for the treatment of CMD.

Should we choose CT angiography first instead of SPECT/PET first for the diagnosis and management of coronary artery disease?

In patients presenting with chest pain, current guidelines recommend the use of coronary computed tomography angiography and single-photon emission tomography/positron emission tomography, both with equal class 1 indication and level of evidence A. There is no clear recommendation on which test should be used as a first-line test. The choice of the test should be based on individualized clinical risk assessment, patient characteristics, local expertise/availability, and patient preferences. In this context, it is fair to ask which non-invasive imaging test to choose. The debate reproduced in this article answers this question by summarizing the considerations in selecting present state-of-the-art criteria of the right test for the right patient to ensure efficient resource utilization, minimize unnecessary testing, and maximize diagnostic accuracy and therapeutic efficacy.

Effects of Medications on Heat Loss Capacity in Chronic Disease Patients: Health Implications Amidst Global Warming

Pharmacological agents used to treat or manage diseases can modify the level of heat strain experienced by chronically ill and elderly patients via different mechanistic pathways. Human thermoregulation is a crucial homeostatic process that maintains body temperature within a narrow range during heat stress through dry (i.e., increasing skin blood flow) and evaporative (i.e., sweating) heat loss, as well as active inhibition of thermogenesis, which is crucial to avoid overheating. Medications can independently and synergistically interact with aging and chronic disease to alter homeostatic responses to rising body temperature during heat stress. This review focuses on the physiologic changes, with specific emphasis on thermolytic processes, associated with medication use during heat stress. The review begins by providing readers with a background of the global chronic disease burden. Human thermoregulation and aging effects are then summarized to give an understanding of the unique physiologic changes faced by older adults. The effects of common chronic diseases on temperature regulation are outlined in the main sections. Physiologic impacts of common medications used to treat these diseases are reviewed in detail, with emphasis on the mechanisms by which these medications alter thermolysis during heat stress. The review concludes by providing perspectives on the need to understand the effects of medication use in hot environments, as well as a summary table of all clinical considerations and research needs of the medications included in this review. SIGNIFICANCE STATEMENT: Long-term medications modulate thermoregulatory function, resulting in excess physiological strain and predisposing patients to adverse health outcomes during prolonged exposures to extreme heat during rest and physical work (e.g., exercise). Understanding the medication-specific mechanisms of altered thermoregulation has importance in both clinical and research settings, paving the way for work toward refining current medication prescription recommendations and formulating mitigation strategies for adverse drug effects in the heat in chronically ill patients.

Atherosclerosis of the iliac arteries for the prediction of erectile dysfunction and epistaxis in men undergoing abdominal CT scan

BACKGROUND

To investigate the association between erectile dysfunction (ED) as well as epistaxis (ES) in relation to the extent of iliac atherosclerosis.

METHODS

In this retrospective cross-sectional study, all consecutive male patients treated at our institution from 01/2016 to 12/2020 undergoing abdominal CT scan were evaluated. Patients (n = 1272) were invited by mail to participate in the study in returning two questionnaires for the evaluation of ED (IIEF-5) and ES. Patients who returned filled-in questionnaires within a 3-month deadline were included in the study. The extent of atherosclerosis in the common iliac artery (CIA) and the internal iliac artery (IIA) was assessed by calcium scoring on unenhanced CT. Stratification of results was performed according to reported IIEF-5 scores and consequential ED groups.

RESULTS

In total, 437 patients (34.4% of contacted) met the inclusion criteria. Forty-two patients did not fulfill predefined age requirements (< 75 years) and 120 patients had to be excluded as calcium scoring on nonenhanced CT was not feasible. Finally, 275 patients were included in the analysis and stratified into groups of "no-mild" (n = 146) and "moderate-severe" (n = 129) ED. The calcium score (r=-0.28, p < 0.001) and the number of atherosclerotic lesions (r=-0.32, p < 0.001) in the CIA + IIA showed a significant negative correlation to the IIEF-5 score, respectively. Patients differed significantly in CIA + IIA calcium score (difference: 167.4, p < 0.001) and number of atherosclerotic lesions (difference: 5.00, p < 0.001) when belonging to the "no-mild" vs. "moderate-severe" ED group, respectively. A multivariable regression model, after adjusting for relevant baseline characteristics, showed that the number of atherosclerotic CIA + IIA lesions was an independent predictor of ED (OR = 1.05, p = 0.036), whereas CIA + IIA calcium score was not (OR = 1.00031, p = 0.20). No relevant correlation was found between ES episodes and IIEF-5 scores (r=-0.069, p = 0.25), CIA + IIA calcium score (r=-0.10, p = 0.87) or number of atherosclerotic CIA + IIA lesions (r=-0.032, p = 0.60), respectively.

CONCLUSIONS

The number of atherosclerotic lesions in the iliac arteries on nonenhanced abdominal CT scans is associated with the severity of ED. This may be used to identify subclinical cardiovascular disease and to quantify the risk for cardiovascular hazards in the future.

TRIAL REGISTRATION

BASEC-Nr. 2020 - 01637.

Diagnostic Puzzles and Cause-Targeted Treatment Strategies in Myocardial Infarction with Non-Obstructive Coronary Arteries: An Updated Review

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is a distinct subtype of myocardial infarction (MI), occurring in about 8-10% of spontaneous MI cases referred for coronary angiography. Unlike MI with obstructive coronary artery disease, MINOCA's pathogenesis is more intricate and heterogeneous, involving mechanisms such as coronary thromboembolism, coronary vasospasm, microvascular dysfunction, dissection, or plaque rupture. Diagnosing MINOCA presents challenges and includes invasive and non-invasive strategies aiming to differentiate it from alternative diagnoses and confirm the criteria of elevated cardiac biomarkers, non-obstructive coronary arteries, and the absence of alternate explanations for the acute presentation. Tailored management strategies for MINOCA hinge on identifying the underlying cause of the infarction, necessitating systematic diagnostic approaches. Furthermore, determining the optimal post-MINOCA medication regimen remains uncertain. This review aims to comprehensively address the current state of knowledge, encompassing diagnostic and therapeutic approaches, in the context of MINOCA while also highlighting the evolving landscape and future directions for advancing our understanding and management of this intricate myocardial infarction subtype.

Revascularization and Left Ventricular Dysfunction for ICD Eligibility

Common triggers for sudden cardiac death (SCD) are transient ischemia, hemodynamic fluctuations, neurocardiovascular influences, and environmental factors. SCD occurs rapidly when sinus rhythm degenerates into ventricular tachycardia (VT) and/or ventricular fibrillation (VF), followed by asystole. Such progressive worsening of the cardiac rhythm is in most cases observed in the setting of ischemic heart disease and often associated with advanced left ventricular (LV) impairment. Revascularization prevents negative outcomes including SCD and heart failure (HF) due to LV dysfunction (LVD). The implantable cardioverter-defibrillator (ICD) on top of medical therapy is superior to antiarrhythmic drugs for patients with LVD and VT/VF. The beneficial effects of ICD have been demonstrated in primary prevention of SCD as well. However, yet debated is the temporal management for patients with LVD who are eligible to ICD prior to revascularization, either through percutaneous or surgical approach. Restoration of coronary blood flow has a dramatic impact on adverse LV remodeling, while it requires aggressive long-term antiplatelet therapy, which might increase complication for eventual ICD procedure when percutaneous strategy is pursued; on the other hand, when LV and/or multiorgan dysfunction is present and coronary artery bypass grafting is chosen, the overall risk is augmented, mostly in HF patients. The aims of this review are to describe the pathophysiologic benefits of revascularization, the studies addressing percutaneous, surgical or no revascularization and ICD implantation, as well as emerging defibrillation strategies for patients deemed at transient risk of SCD and/or at higher risk for transvenous ICD implantation.

Coronary angiography-derived index for assessing microcirculatory resistance in patients with non-obstructed vessels: The FLASH IMR study

BACKGROUND

Assessing index of microcirculatory resistance (IMR) is customarily performed using intracoronary wires fitted with sensors by at least 3 intracoronary injections of 3 to 4 mL of room-temperature saline during sustained hyperemia, which is time- and cost-consuming.

METHODS

The FLASH IMR study is a prospective, multicenter, randomized study to assess the diagnostic performance of coronary angiography-derived IMR (caIMR) in patients with suspected myocardial ischemia with nonobstructive coronary arteries using wire-based IMR as a reference. The caIMR was calculated by an optimized computational fluid dynamics model simulating hemodynamics during diastole based on coronary angiograms. TIMI frame count and aortic pressure were included in computation. caIMR was determined onsite in real time and compared blind to wire-based IMR by an independent core laboratory, using wire-based IMR ≥25 units as indicative of abnormal coronary microcirculatory resistance. The primary endpoint was the diagnostic accuracy of caIMR, using wire-based IMR as a reference, with a pre-specified performance goal of 82%.

RESULTS

A total of 113 patients underwent paired caIMR and wire-based IMR measurements. Order of performance of tests was based on randomization. Diagnostic accuracy, sensitivity, specificity, positive and negative predictive values of caIMR were 93.8% (95% CI: 87.7%-97.5%), 95.1% (95% CI: 83.5%- 99.4%), 93.1% (95% CI: 84.5%-97.7%), 88.6% (95% CI: 75.4%-96.2%) and 97.1% (95% CI: 89.9%-99.7%). The receiver-operating curve for caIMR to diagnose abnormal coronary microcirculatory resistance had area under the curve of 0.963 (95% CI: 0.928-0.999).

CONCLUSIONS

Angiography-based caIMR has a good diagnostic yield with wire-based IMR.

CLINICALTRIALS

GOV IDENTIFIER

NCT05009667.

Moving from one state to another among patients experiencing unexplained chest pain during physical activity: A secondary qualitative analysis by Meleis transition theory

BACKGROUND

Unexplained chest pain is a common condition in medical settings. Nurses usually coordinate the rehabilitation of patients. Physical activity is recommended; however, it is one of the major avoidance behaviours in patients with coronary heart disease. There is a need for a deeper understanding of the transition that patients with unexplained chest pain undergo during physical activity.

AIM

To develop deeper understanding about experiences of transition in patients with unexplained chest pain during physical activity.

DESIGN

Secondary qualitative analysis of data from three exploratory studies.

METHOD

Meleis et al.'s transition theory was used as a framework for the secondary analysis.

FINDINGS

The transition was complex and multidimensional. The participants experienced personal processes of change toward health within the illness, corresponding to indicators of healthy transitions.

CONCLUSION

The process can be identified as a transition from an uncertain and often sick role to a healthy role. Knowledge regarding transition promotes a person-centred approach in which patients' perspectives are included. Nurses and other health professionals can better direct and plan the caring and rehabilitation of patients with unexplained chest pain by deepening their knowledge of the transition process based on physical activity.

Energy metabolism: A critical target of cardiovascular injury

Cardiovascular diseases are the main killers threatening human health. Many studies have shown that abnormal energy metabolism plays a key role in the occurrence and development of acute and chronic cardiovascular diseases. Regulating cardiac energy metabolism is a frontier topic in the treatment of cardiovascular diseases. However, we are not very clear about the choice of different substrates, the specific mechanism of energy metabolism participating in the course of cardiovascular disease, and how to develop appropriate drugs to regulate energy metabolism to treat cardiovascular disease. Therefore, this paper reviews how energy metabolism participates in cardiovascular pathophysiological processes and potential drugs aimed at interfering energy metabolism.It is expected to provide good suggestions for promoting the clinical prevention and treatment of cardiovascular diseases from the perspective of energy metabolism.

Incremental value of non-invasive myocardial work for the evaluation and prediction of coronary microvascular dysfunction in angina with no obstructive coronary artery disease

Background

Evidence suggests that patients suffering from angina with no obstructive coronary artery disease (ANOCA) experience coronary microvascular dysfunction (CMD). We aimed to understand the diagnosis value of noninvasive myocardial work indices (MWIs) with left ventricular pressure-strain loop (LV PSL) by echocardiography in ANOCA patients with CMD.

Methods

97 patients with ANOCA were recruited. All subjects underwent standard echocardiography with traditional ultrasound parameters, two-dimensional speckle-tracking echocardiography with global longitudinal strain (GLS), LV PSL with MWIs include global work index (GWI), global constructive work (GCW), global waste work (GWW) and global work efficiency (GWE). In addition, all enrolled cases underwent high-dose adenosine stress echocardiography (SE) with coronary flow velocity reserve (CFVR). CMD was defined as CFVR <2.0.

Results

Of the 97 patients with ANOCA, 52 were placed in the CMD group and 45 in the control group. GWI and GCW were decreased significantly in the CMD group compared with the control group (P < 0.001 for both). GWI and GCW were moderately correlated with CFVR (r = 0.430, P < 0.001 and r = 0.538, P < 0.001, respectively). In the multiple logistic regression analyses, GCW was identified as the only independent echocardiography parameter associated with CMD after adjusting for age and baseline APV [OR (95%CI) 1.009 (1.005-1.013); P < 0.001]. Moreover, the best predictor of CMD in patients with ANOCA using receiver operating characteristic (ROC) curve was GWI and GCW, with an area under the curve (AUC) of 0.800 and 0.832, sensitivity of 67.3% and 78.8%, specificity of 80.0% and 75.6%, respectively.

Conclusion

MWIs with LV PSL is a new method to detect LV systolic function noninvasively in ANOCA patients with CMD.

Clinical characteristics, risk factors, and prognostic analyses of coronary small vessel disease: a retrospective cohort study of 986 patients

BACKGROUND AND AIMS

Coronary small vessel disease (CSVD) is often associated with significant percutaneous coronary intervention (PCI) related complications, complex lesions, complex PCI, and poor long-term prognosis. We designed this retrospective study to clarify the characteristics, risk factors, and prognostic analyses of CSVD in Chinese populations.

METHODS

A total of 986 patients who underwent coronary angiography and stent implantation at the First Affiliated Hospital of Zhejiang University School of Medicine were evaluated. Patients were grouped into CSVD or non-small vessel disease (non-CSVD) according to stent diameter. Clinical data, coronary angiography, and long-term follow-up were recorded. Multivariate logistic regression, the Kaplan-Meier method, Log-rank Test, and Cox regression model were used for statistical analysis.

RESULTS

Alcohol consumption (OR = 0.420, 95% CI: 0.299-0.588, P < 0.001) was implicated as a negative CSVD correlation factor. CSVD was more likely to be associated with multi-vessel lesions (79.2% vs. 49.4%, P < 0.001), bifurcation lesions (24.0% vs. 12.4%, P < 0.001), chronic total obstruction lesions (29.5% vs. 9.4%, P < 0.001), and long lesions (55.2% vs. 35.7%, P < 0.001), which reduced the efficacy of revascularization (70.1% vs. 85.1%, P < 0.001). In the follow-ups, cardiac death (2.3% vs. 0.4%, P = 0.008), stroke (1.9% vs. 0.3%, P = 0.007), target lesion revascularization (5.8% vs. 2.9%, P = 0.029), target vessel revascularization (6.8% vs. 3.4%, P = 0.016), and non-target vessel revascularization (7.8% vs. 4.0%, P = 0.012) were all substantially higher in CSVD patients. Troponin I level (OR = 1.008, 95% CI: 1.004-1.012, P < 0.001), complete revascularization (OR = 0.292, 95% CI: 0.160-0.531, P < 0.001), and aspirin administration (OR = 0.041, 95% CI: 0.013-0.131, P < 0.001) were independent predictors of MACE events of all patients.

CONCLUSION

Compared to non-CSVD, CSVD was associated with more complex lesions, had worse revascularization efficacy, and a poorer prognosis.

EXACT Trial: Results of the Phase 1 Dose-Escalation Study

BACKGROUND

New therapies are needed for patients with refractory angina. Encoberminogene rezmadenovec (XC001), a novel adenoviral-5 vector coding for all 3 major isoforms of VEGF (vascular endothelial growth factor), demonstrated enhanced local angiogenesis in preclinical models; however, the maximal tolerated dose and safety of direct epicardial administration remain unknown.

METHODS

In the phase 1 portion of this multicenter, open-label, single-arm, dose-escalation study, patients with refractory angina received increasing doses of encoberminogene rezmadenovec (1×109, 1×1010, 4×1010, and 1×1011 viral particles) to evaluate its safety, tolerability, and preliminary efficacy. Patients had class II to IV angina on maximally tolerated medical therapy, demonstrable ischemia on stress testing, and were angina-limited on exercise treadmill testing. Patients underwent minithoracotomy with epicardial delivery of 15 0.1-mL injections of encoberminogene rezmadenovec. The primary outcome was safety via adverse event monitoring over 6 months. Efficacy assessments included difference from baseline to months 3, 6 (primary), and 12 in total exercise duration, myocardial perfusion deficit using positron emission tomography, angina class, angina frequency, and quality of life.

RESULTS

From June 2, 2020 to June 25, 2021, 12 patients were enrolled into 4 dosing cohorts with 1×1011 viral particle as the highest planned dose. Seventeen serious adverse events were reported in 7 patients; none were related to study drug. Six serious adverse events in 4 patients were related to the thoracotomy, 3 non-serious adverse events were possibly related to study drug. The 2 lowest doses did not demonstrate improvements in total exercise duration, myocardial perfusion deficit, or angina frequency; however, there appeared to be improvements in all parameters with the 2 higher doses.

CONCLUSIONS

Epicardial delivery of encoberminogene rezmadenovec via minithoracotomy is feasible, and up to 1×1011 viral particle appears well tolerated. A dose response was observed across 4 dosing cohorts in total exercise duration, myocardial perfusion deficit, and angina class. The highest dose (1×1011 viral particle) was carried forward into phase 2.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04125732.

Echocardiographic assessment of primary microvascular angina and primary coronary microvascular dysfunction

There is an increasing interest in the role of echocardiography in the evaluation of primary microvascular angina, which is attributed to primary coronary microvascular dysfunction. Valid echocardiographic techniques are expected to facilitate the diagnosis and follow-up of these patients and would be valuable for research purposes and therapy evaluation. However, adequate echocardiographic data are lacking, and the interpretation of the limited available literature is hindered by the previous addition of microvascular angina under more inclusive entities, such as cardiac syndrome X. In experienced hands, the assessment of primary coronary microvascular dysfunction in patients with suspected primary microvascular angina, using multiple echocardiographic techniques is feasible, relatively inexpensive, and safe. Exclusion of obstructive epicardial coronary artery disease is, however, a prerequisite for diagnosis. Two-dimensional transthoracic echocardiography, routine stress echocardiography, and speckle-tracking echocardiography indirectly assess primary coronary microvascular dysfunction by evaluating potential impairment in myocardial function and lack diagnostic sensitivity and specificity. Conversely, certain echocardiographic techniques, including Doppler-derived coronary flow velocity reserve and myocardial contrast echocardiography, assess some coronary microvascular dysfunction parameters and have exhibited diagnostic and prognostic potentials. Doppler-derived coronary flow velocity reserve is the best studied and only guideline-approved echocardiographic technique for documenting coronary microvascular dysfunction in patients with suspected microvascular angina. Myocardial contrast echocardiography, by comparison, can detect heterogeneous and patchy myocardial involvement by coronary microvascular dysfunction, which is an advantage over the common practice of coronary flow velocity reserve assessment in a single vessel (commonly the left anterior descending artery) which only reflects regional microvascular function. However, there is no consensus regarding the diagnostic criteria, and expertise performing this technique is limited. Echocardiography remains underexplored and inadequately utilized in the setting of microvascular angina and coronary microvascular dysfunction. Appraisal of the current echocardiographic literature regarding coronary microvascular dysfunction and microvascular angina is important to stay current with the progress in its clinical recognition and create a basis for future research and technological advancements.

Prognostic impacts of geriatric nutritional risk index in patients with ischemic heart failure after percutaneous coronary intervention

BACKGROUND

Malnutrition has been proven to be associated with increased risk of poor prognosis in a series of diseases. This study explored the association between poor nutritional status and prognosis in patients with ischemic heart failure (IHF) undergoing percutaneous coronary intervention (PCI).

METHODS

The study enrolled 1745 patients with IHF undergoing PCI. The mean follow-up time was 28.7 months. Nutritional status was assessed by geriatric nutritional risk index (GNRI). All patients were divided into four groups according to GNRI quartiles (median and interquartile range: 103.8, 99.9-107.7). The primary endpoint was major adverse cardiovascular events (MACE), and the secondary endpoints were each component of the primary endpoint as follows: all-cause mortality, non-fatal myocardial infarction (MI), and any revascularization. The Kaplan-Meier survival analyses were performed to evaluate the incidence of the endpoints among 4 groups. The multivariate Cox proportional hazards analysis confirmed the independent effect of GNRI on the primary endpoint and secondary endpoints. The restricted cubic spline (RCS) was performed to evaluate the non-linear association of GNRI with MACE.

RESULT

The negative correlation of the GNRI with MACE (Log-rank P < 0.001), all-cause mortality (Log-rank P < 0.001) and any revascularization (Log-rank P < 0.001) was confirmed through the Kaplan-Meier curves. Multivariate analysis showed that the decreased GNRI was independently related to increased risk of MACE (Quartile 1 versus Quartile 4: HR, 95% CI: 2.66, 2.01-3.51, P < 0.001), all-cause mortality (Quartile 1 versus Quartile 4: HR, 95% CI: 2.33, 1.54-3.50, P < 0.001) and any revascularization (Quartile 1 versus Quartile 4: HR, 95% CI: 3.42, 2.22-5.27, P < 0.001). In addition, the non-linear association of GNRI with MACE was shown through RCS and the risk of MACE decreased as the GNRI increased in general (Non-linear P < 0.001).

CONCLUSION

Decreased GNRI was an independent risk factor of MACE in IHF patients undergoing PCI.

Endothelial ILK induces cardioprotection by preventing coronary microvascular dysfunction and endothelial-to-mesenchymal transition

Endothelial dysfunction is an early event in coronary microvascular disease. Integrin-linked kinase (ILK) prevents endothelial nitric oxide synthase (eNOS) uncoupling and, thus, endothelial dysfunction. However, the specific role of endothelial ILK in cardiac function remains to be fully elucidated. We hypothesised that endothelial ILK plays a crucial role in maintaining coronary microvascular function and contractile performance in the heart. We generated an endothelial cell-specific ILK conditional knock-out mouse (ecILK cKO) and investigated cardiovascular function. Coronary endothelial ILK deletion significantly impaired cardiac function: ejection fraction, fractional shortening and cardiac output decreased, whilst left ventricle diastolic internal diameter decreased and E/A and E/E' ratios increased, indicating not only systolic but also diastolic dysfunction. The functional data correlated with extensive extracellular matrix remodelling and perivascular fibrosis, indicative of adverse cardiac remodelling. Mice with endothelial ILK deletion suffered early ischaemic-like events with ST elevation and transient increases in cardiac troponins, which correlated with fibrotic remodelling. In addition, ecILK cKO mice exhibited many features of coronary microvascular disease: reduced cardiac perfusion, impaired coronary flow reserve and arterial remodelling with patent epicardial coronary arteries. Moreover, endothelial ILK deletion induced a moderate increase in blood pressure, but the antihypertensive drug Losartan did not affect microvascular remodelling whilst only partially ameliorated fibrotic remodelling. The plasma miRNA profile reveals endothelial-to-mesenchymal transition (endMT) as an upregulated pathway in endothelial ILK conditional KO mice. Our results show that endothelial cells in the microvasculature in endothelial ILK conditional KO mice underwent endMT. Moreover, endothelial cells isolated from these mice and ILK-silenced human microvascular endothelial cells underwent endMT, indicating that decreased endothelial ILK contributes directly to this endothelial phenotype shift. Our results identify ILK as a crucial regulator of microvascular endothelial homeostasis. Endothelial ILK prevents microvascular dysfunction and cardiac remodelling, contributing to the maintenance of the endothelial cell phenotype.

Coronary "Microvascular Dysfunction": Evolving Understanding of Pathophysiology, Clinical Implications, and Potential Therapeutics

Until recently, it has been generally held that stable angina pectoris (SAP) primarily reflects the presence of epicardial coronary artery stenoses due to atheromatous plaque(s), while acute myocardial infarction (AMI) results from thrombus formation on ruptured plaques. This concept is now challenged, especially by results of the ORBITA and ISCHEMIA trials, which showed that angioplasty/stenting does not substantially relieve SAP symptoms or prevent AMI or death in such patients. These disappointing outcomes serve to redirect attention towards anomalies of small coronary physiology. Recent studies suggest that coronary microvasculature is often both structurally and physiologically abnormal irrespective of the presence or absence of large coronary artery stenoses. Structural remodelling of the coronary microvasculature appears to be induced primarily by inflammation initiated by mast cell, platelet, and neutrophil activation, leading to erosion of the endothelial glycocalyx. This leads to the disruption of laminar flow and the facilitation of endothelial platelet interaction. Glycocalyx shedding has been implicated in the pathophysiology of coronary artery spasm, cardiovascular ageing, AMI, and viral vasculitis. Physiological dysfunction is closely linked to structural remodelling and occurs in most patients with myocardial ischemia, irrespective of the presence or absence of large-vessel stenoses. Dysfunction includes the impairment of platelet and vascular responsiveness to autocidal coronary vasodilators, such as nitric oxide, prostacyclin, and hydrogen sulphide, and predisposes both to coronary vasoconstriction and to a propensity for microthrombus formation. These findings emphasise the need for new directions in medical therapeutics for patients with SAP, as well as a wide range of other cardiovascular disorders.

Exploring the active ingredients and mechanism of Shenzhi Tongxin capsule against microvascular angina based on network pharmacology and molecular docking

BACKGROUND

Microvascular angina (MVA) substantially threatens human health, and the Shenzhi Tongxin (SZTX) capsule demonstrates a remarkable cardioprotective effect, making it a potential treatment option for MVA. However, the precise mechanism of action for this medication remains unclear. This study utilized network pharmacology and molecular docking technology to investigate the active components and potential mechanisms underlying the efficacy of the SZTX capsule in alleviating MVA.

METHODS

The main ingredients of the SZTX capsule, along with their targets proteins and potential disease targets associated with MVA, were extracted from public available databases. This study utilized the STRING database and Cytoscape 3.7.2 software to establish a protein-protein interaction network and determine key signaling pathway targets. Subsequently, the DAVID database was utilized to conduct Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes analyses on the intersection targets. To further investigate the molecular interactions, Autodock and PyMOL software were employed to perform molecular docking and visualize the resulting outcomes.

RESULTS

A total of 130 and 142 bioactive ingredients and intersection targets were identified respectively. Six core targets were obtained through protein-protein interaction network analysis. Gene Ontology enrichment analysis showed that 610 biological processes, 75 cellular components, and 92 molecular functions were involved. The results of Kyoto Encyclopedia of Genes and Genomes enrichment analyses indicated that SZTX capsule molecular mechanism in the treatment of MVA may be related to several pathways, including mitogen-activated protein kinases, PI3K-Akt, HIF-1, and others. The results of molecular docking showed that the 7 key active ingredients of SZTX capsule had good binding ability to 6 core proteins.

CONCLUSION

SZTX capsule potentially exerts its effects by targeting multiple signaling pathways, including the mitogen-activated protein kinases signaling pathway, PI3K-Akt signaling pathway, and HIF-1 signaling pathway. This multi-target approach enables SZTX capsule to inhibit inflammation, alleviate oxidative stress, regulate angiogenesis, and enhance endothelial function.

Coronary microvascular dysfunction and cardiovascular disease: Pathogenesis, associations and treatment strategies

Coronary microvascular dysfunction (CMD) is a high-risk factor for a variety of cardiovascular events. Due to its complex aetiology and concealability, knowledge of the pathophysiological mechanism of CMD is still limited at present, which greatly restricts its clinical diagnosis and treatment. Studies have shown that CMD is closely related to a variety of cardiovascular diseases, can aggravate the occurrence and development of cardiovascular diseases, and is closely related to a poor prognosis in patients with cardiovascular diseases. Improving coronary microvascular remodelling and increasing myocardial perfusion might be promising strategies for the treatment of cardiovascular diseases. In this paper, the pathogenesis and functional assessment of CMD are reviewed first, along with the relationship of CMD with cardiovascular diseases. Then, the latest strategies for the treatment of CMD and cardiovascular diseases are summarized. Finally, urgent scientific problems in CMD and cardiovascular diseases are highlighted and future research directions are proposed to provide prospective insights for the prevention and treatment of CMD and cardiovascular diseases in the future.

Shexiang Tongxin Dropping Pill alleviates M1 macrophage polarization-induced inflammation and endothelial dysfunction to reduce coronary microvascular dysfunction via the dectin-1/Syk/IRF5 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Shexiang Tongxin Dropping Pill (STDP), a traditional Chinese medicine compound, is fragrant, invigorates the qi, unblocks pulses, activates the blood circulation, removes blood stasis, and relieves pain. It is used clinically to treat coronary heart disease and angina pectoris. Coronary microvascular dysfunction (CMD) is associated with increased morbidity and mortality from cardiovascular events. Endothelial dysfunction and inflammation have been verified as its underlying causes. STDP can ameliorate CMD, but the mechanism has not been fully elucidated.

AIM OF THE STUDY

To explore the effects of STDP on M1 macrophage polarization-induced inflammation and endothelial dysfunction as an inhibitor of CMD, and to determine its mechanisms of action.

MATERIALS AND METHODS

The CMD rat model was established by left anterior descending artery (LAD) ligation. The efficacy of STDP against CMD was evaluated by echocardiography, optical microangiography, Evans blue staining, and histological examination. The OGD/R-induced endothelial injury model, the endothelial injury-induced sterile inflammation model, the Dectin-1 overexpression model, and the Dectin-1-overexpressing RAW264.7 macrophage supernatant-stimulated HUVEC-induced secondary injury of endothelial function model were established to confirm the efficacy of STDP against M1 macrophage polarization-induced inflammation and endothelial dysfunction.

RESULTS

STDP blunted the deterioration of cardiac function and ameliorated CMD by reducing inflammatory cell infiltration and endothelial dysfunction in CMD rats. Endothelial injury and Dectin-1 overexpression induced M1 macrophage polarization and inflammation. Mechanically, STDP hindered M1 macrophage polarization and inflammation by inhibiting the Dectin-1/Syk/IRF5 pathway both in vivo and in vitro. STDP alleviated endothelial dysfunction induced by Dectin-1 overexpression in macrophages.

CONCLUSION

STDP can alleviate M1 macrophage polarization-induced inflammation and endothelial dysfunction against CMD via the Dectin-1/Syk/IRF5 pathway. Dectin-1-associated M1 macrophage polarization might be developed as a novel target for ameliorating CMD.

Entropy-based reliable non-invasive detection of coronary microvascular dysfunction using machine learning algorithm

PURPOSE

Coronary microvascular dysfunction (CMD) is emerging as an important cause of myocardial ischemia, but there is a lack of a non-invasive method for reliable early detection of CMD.

AIM

To develop an electrocardiogram (ECG)-based machine learning algorithm for CMD detection that will lay the groundwork for patient-specific non-invasive early detection of CMD.

METHODS

Vectorcardiography (VCG) was calculated from each 10-second ECG of CMD patients and healthy controls. Sample entropy (SampEn), approximate entropy (ApEn), and complexity index (CI) derived from multiscale entropy were extracted from ST-T segments of each lead in ECGs and VCGs. The most effective entropy subset was determined using the sequential backward selection algorithm under the intra-patient and inter-patient schemes, separately. Then, the corresponding optimal model was selected from eight machine learning models for each entropy feature based on five-fold cross-validations. Finally, the classification performance of SampEn-based, ApEn-based, and CI-based models was comprehensively evaluated and tested on a testing dataset to investigate the best one under each scheme.

RESULTS

ApEn-based SVM model was validated as the optimal one under the intra-patient scheme, with all testing evaluation metrics over 0.8. Similarly, ApEn-based SVM model was selected as the best one under the intra-patient scheme, with major evaluation metrics over 0.8.

CONCLUSIONS

Entropies derived from ECGs and VCGs can effectively detect CMD under both intra-patient and inter-patient schemes. Our proposed models may provide the possibility of an ECG-based tool for non-invasive detection of CMD.

Accelerated ageing and coronary microvascular dysfunction in chronic heart failure in Tgαq*44 mice

Age represents a major risk factor in heart failure (HF). However, the mechanisms linking ageing and HF are not clear. We aimed to identify the functional, morphological and transcriptomic changes that could be attributed to cardiac ageing in a model of slowly progressing HF in Tgαq*44 mice in reference to the cardiac ageing process in FVB mice. In FVB mice, ageing resulted in the impairment of diastolic cardiac function and in basal coronary flow (CF), perivascular and interstitial fibrosis without changes in the cardiac activity of angiotensin-converting enzyme (ACE) or aldosterone plasma concentration. In Tgαq*44 mice, HF progression was featured by the impairment of systolic and diastolic cardiac function and in basal CF that was associated with a distinct rearrangement of the capillary architecture, pronounced perivascular and interstitial fibrosis, progressive activation of cardiac ACE and systemic angiotensin-aldosterone-dependent pathways. Interestingly, cardiac ageing genes and processes were represented in Tgαq*44 mice not only in late but also in early phases of HF, as evidenced by cardiac transcriptome analysis. Thirty-four genes and 8 biological processes, identified as being ageing related, occurred early and persisted along HF progression in Tgαq*44 mice and were mostly associated with extracellular matrix remodelling and fibrosis compatible with perivascular fibrosis resulting in coronary microvascular dysfunction (CMD) in Tgαq*44 mice. In conclusion, accelerated and persistent cardiac ageing contributes to the pathophysiology of chronic HF in Tgαq*44 mice. In particular, prominent perivascular fibrosis of microcirculation resulting in CMD represents an accelerated cardiac ageing phenotype that requires targeted treatment in chronic HF.

Evaluation of recipients with significant comorbidity - Patients with cardiovascular disease

Liver transplant(ation) (LT) is the most effective treatment for patients with decompensated liver disease. The increasing prevalence of obesity and type 2 diabetes and the growing number of patients with non-alcoholic fatty liver disease being evaluated for LT, have resulted in a greater proportion of LT candidates presenting with a higher risk of cardiovascular disease. As cardiovascular disease is a major cause of morbidity and mortality after LT, a thorough cardiovascular evaluation pre-LT is crucial. In this review, we discuss the latest evidence on the cardiovascular evaluation of LT candidates and we focus on the most prevalent conditions, namely ischaemic heart disease, atrial fibrillation and other arrhythmias, valvular heart disease, and cardiomyopathies. LT candidates undergo an electrocardiogram, a resting transthoracic echocardiography and an assessment of their cardiopulmonary functional ability as part of their standardised pre-LT work-up. Further diagnostic work-up is undertaken based on the results of the baseline evaluation and may include a coronary computed tomography angiography in patients with cardiovascular risk factors. The evaluation of potential LT candidates for cardiovascular disease requires a multidisciplinary approach, with input from anaesthetists, cardiologists, hepatologists and transplant surgeons.

Effects of Soluble Guanylate Cyclase Stimulators and Activators on Anti-Aggregatory Signalling in Patients with Coronary Artery Spasm

Impairment of the nitric oxide/soluble guanylate cyclase (NO)/sGC) signalling cascade is associated with many forms of cardiovascular disease, resulting not only in compromised vasodilatation but also loss of anti-aggregatory homeostasis. Myocardial ischaemia, heart failure, and atrial fibrillation are associated with moderate impairment of NO/sGC signalling, and we have recently demonstrated that coronary artery spasm (CAS) is engendered by severe impairment of platelet NO/sGC activity resulting in combined platelet and vascular endothelial damage. We therefore sought to determine whether sGC stimulators or activators might normalise NO/sGC homeostasis in platelets. ADP-induced platelet aggregation and its inhibition by the NO donor sodium nitroprusside (SNP), the sGC stimulator riociguat (RIO), and the sCG activator cinaciguat (CINA) alone or in addition to SNP were quantitated. Three groups of individuals were compared: normal subjects (n = 9), patients (Group 1) with myocardial ischaemia, heart failure and/or atrial fibrillation (n = 30), and patients (Group 2) in the chronic stage of CAS (n = 16). As expected, responses to SNP were impaired (p = 0.02) in patients versus normal subjects, with Group 2 patients most severely affected (p = 0.005). RIO alone exerted no anti-aggregatory effects but potentiated responses to SNP to a similar extent irrespective of baseline SNP response. CINA exerted only intrinsic anti-aggregatory effects, but the extent of these varied directly (r = 0.54; p = 0.0009) with individual responses to SNP. Thus, both RIO and CINA tend to normalise anti-aggregatory function in patients in whom NO/sGC signalling is impaired. The anti-aggregatory effects of RIO consist entirely of potentiation of NO, which is not selective of platelet NO resistance. However, the intrinsic anti-aggregatory effects of CINA are most marked in individuals with initially normal NO/sGC signalling, and thus their magnitude is at variance with extent of physiological impairment. These data suggest that RIO and other sGC stimulators should be evaluated for clinical utility in both prophylaxis and treatment of CAS.

Assessment of hemodynamic indices of conjunctival microvascular function in patients with coronary microvascular dysfunction

OBJECTIVE

Coronary microvascular dysfunction (CMD) is a cause of ischaemia with non-obstructive coronary arteries (INOCA). It is notoriously underdiagnosed due to the need for invasive microvascular function testing. We hypothesized that systemic microvascular dysfunction could be demonstrated non-invasively in the microcirculation of the bulbar conjunctiva in patients with CMD.

METHODS

Patients undergoing coronary angiography for the investigation of chest pain or dyspnoea, with physiologically insignificant epicardial disease (fractional flow reserve ≥0.80) were recruited. All patients underwent invasive coronary microvascular function testing. We compared a cohort of patients with evidence of CMD (IMR ≥25 or CFR <2.0); to a group of controls (IMR <25 and CFR ≥2.0). Conjunctival imaging was performed using a previously validated combination of a smartphone and slit-lamp biomicroscope. This technique allows measurement of vessel diameter and other indices of microvascular function by tracking erythrocyte motion.

RESULTS

A total of 111 patients were included (43 CMD and 68 controls). There were no differences in baseline demographics, co-morbidities or epicardial coronary disease severity. The mean number of vessel segments analysed per patient was 21.0 ± 12.8 (3.2 ± 3.5 arterioles and 14.8 ± 10.8 venules). In the CMD cohort, significant reductions were observed in axial/cross-sectional velocity, blood flow, wall shear rate and stress.

CONCLUSION

The changes in microvascular function linked to CMD can be observed non-invasively in the bulbar conjunctiva. Conjunctival vascular imaging may have utility as a non-invasive tool to both diagnose CMD and augment conventional cardiovascular risk assessment.

Obesity-Induced Coronary Microvascular Disease Is Prevented by iNOS Deletion and Reversed by iNOS Inhibition

Coronary microvascular disease (CMD) caused by obesity and diabetes is major contributor to heart failure with preserved ejection fraction; however, the mechanisms underlying CMD are not well understood. Using cardiac magnetic resonance applied to mice fed a high-fat, high-sucrose diet as a model of CMD, we elucidated the role of inducible nitric oxide synthase (iNOS) and 1400W, an iNOS antagonist, in CMD. Global iNOS deletion prevented CMD along with the associated oxidative stress and diastolic and subclinical systolic dysfunction. The 1400W treatment reversed established CMD and oxidative stress and preserved systolic/diastolic function in mice fed a high-fat, high-sucrose diet. Thus, iNOS may represent a therapeutic target for CMD.