Prevalence of Coronary Microvascular Dysfunction Among Patients With Chest Pain and Nonobstructive Coronary Artery Disease

Contemporary Management of Refractory Angina

Refractory angina (RA) is defined as chest pain caused by coronary ischemia in patients on maximal medical therapy and is not amenable to revascularization despite advanced coronary artery disease (CAD). The long-term prognosis has improved with optimal medical therapy including risk factor modification. Still, patients are left with major impairment in quality of life and have high resource utilization with limited treatment options. We review the novel invasive and noninvasive therapies under investigation for RA.

Human coronary microvascular contractile dysfunction associates with viable synthetic smooth muscle cells

AIMS

Coronary microvascular smooth muscle cells (SMCs) respond to luminal pressure by developing myogenic tone (MT), a process integral to the regulation of microvascular perfusion. The cellular mechanisms underlying poor myogenic reactivity in patients with heart valve disease are unknown and form the focus of this study.

METHODS AND RESULTS

Intramyocardial coronary micro-arteries (IMCAs) isolated from human and pig right atrial (RA) appendage and left ventricular (LV) biopsies were studied using pressure myography combined with confocal microscopy. All RA- and LV-IMCAs from organ donors and pigs developed circa 25% MT. In contrast, 44% of human RA-IMCAs from 88 patients with heart valve disease had poor (<10%) MT yet retained cell viability and an ability to raise cytoplasmic Ca2+ in response to vasoconstrictor agents. Comparing across human heart chambers and species, we found that based on patient medical history and six tests, the strongest predictor of poor MT in IMCAs was increased expression of the synthetic marker caldesmon relative to the contractile marker SM-myosin heavy chain. In addition, high resolution imaging revealed a distinct layer of longitudinally aligned SMCs between ECs and radial SMCs, and we show poor MT was associated with disruptions in these cellular alignments.

CONCLUSION

These data demonstrate the first use of atrial and ventricular biopsies from patients and pigs to reveal that impaired coronary MT reflects a switch of viable SMCs towards a synthetic phenotype, rather than a loss of SMC viability. These arteries represent a model for further studies of coronary microvascular contractile dysfunction.

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.

Relationship between Fragmented QRS and Microvascular Dysfunction in Masked Hypertension

Aim

The aim of this study was to investigate the presence of fQRS and its association with subclinical systolic and microvascular dysfunction in patients with masked hypertension (MH).

Methods

The study population consisted of 95 (mean age 48.9 ± 11.3, 61% males) subjects with MH and 80 age- and gender-matched healthy individuals who served as a control group. Coronary flow reserve (CFR) using transthoracic echocardiography and for left ventricular global longitudinal strain (LVGLS) using speckle-tracking strain imaging were performed. Patients with MH were stratified into two groups according to the presence of fQRS on surface electrocardiogram.

Results

Fragmented QRS was more common among MH patients compared with controls (38.9% vs. 6.25%, p < 0.003). CFR was significantly lower in patients with fQRS compared with those without fQRS and controls (p < 0.001). Likewise, LVGLS values were lower in MH patients with fQRS (p < 0.001) compared with subjects without fQRS and controls. Fragmented fQRS was significantly correlated with systolic blood pressure, CFR, and LVGLS. Multivariate analysis showed that the presence of fQRS, number of leads, and CFR were independent predictors of subclinical systolic dysfunction. With ROC cure analysis, number of leads with fQRS ≥4 was the optimal value for predicting the presence of subclinical systolic dysfunction in subjects with MH.

Conclusions

Fragmented QRS is more frequent among subjects with MH compared with controls. The presence of fQRS is related with pronounced subclinical left ventricular systolic dysfunction. Furthermore, CFR was significantly reduced in subjects with MH, a finding supposed that microvascular dysfunction to be a mechanistic link.

Mental Stress and Cardiovascular Health-Part I

Epidemiological studies have shown that a substantial proportion of acute coronary events occur in individuals who lack the traditional high-risk cardiovascular (CV) profile. Mental stress is an emerging risk and prognostic factor for coronary artery disease and stroke, independently of conventional risk factors. It is associated with an increased rate of CV events. Acute mental stress may develop as a result of anger, fear, or job strain, as well as consequence of earthquakes or hurricanes. Chronic stress may develop as a result of long-term or repetitive stress exposure, such as job-related stress, low socioeconomic status, financial problems, depression, and type A and type D personality. While the response to acute mental stress may result in acute coronary events, the relationship of chronic stress with increased risk of coronary artery disease (CAD) is mainly due to acceleration of atherosclerosis. Emotionally stressful stimuli are processed by a network of cortical and subcortical brain regions, including the prefrontal cortex, insula, amygdala, hypothalamus, and hippocampus. This system is involved in the interpretation of relevance of environmental stimuli, according to individual’s memory, past experience, and current context. The brain transduces the cognitive process of emotional stimuli into hemodynamic, neuroendocrine, and immune changes, called fight or flight response, through the autonomic nervous system and the hypothalamic–pituitary–adrenal axis. These changes may induce transient myocardial ischemia, defined as mental stress-induced myocardial ischemia (MSIMI) in patients with and without significant coronary obstruction. The clinical consequences may be angina, myocardial infarction, arrhythmias, and left ventricular dysfunction. Although MSIMI is associated with a substantial increase in CV mortality, it is usually underestimated because it arises without pain in most cases. MSIMI occurs at lower levels of cardiac work than exercise-induced ischemia, suggesting that the impairment of myocardial blood flow is mainly due to paradoxical coronary vasoconstriction and microvascular dysfunction.

ShareHeart: A patient journey map of patients with ischemia and non-obstructive coronary artery disease based on qualitative research

AIMS AND OBJECTIVES

To visualise the health care experiences and needs of patients with ischemia with non-obstructive coronary arteries in a patient journey map. As such, future design challenges can be provided, and it can be used for future healthcare optimization.

BACKGROUND

Ischemia with non-obstructive coronary arteries is a chronic cardiac condition caused by vascular dysfunctions. Ischemia with non-obstructive coronary arteries is often unrecognised, significantly impairs daily functioning, and is more prevalent among women. Patients' experiences remain unexplored, and a clear patient-centered care pathway is lacking.

DESIGN

A qualitative interpretative research design was performed and the standards for reporting qualitative research (SRQR) has been used.

METHODS

In total, 36 women were included and participated in eight semi-structured focus group interviews. Thematic analysis was used, and identified themes were further classified using 'patient journey mapping.' Additionally, Picker's 'eight principles of patient-centered care' were linked to the results and integrated in the patient journey map.

RESULTS

Participants experienced a lack of familiarity with the specific cardiac condition by healthcare providers, repeated hospitalisation, testing and referrals, shortage of specialised cardiologists, and feelings of not being heard. In addition, needs for a multidisciplinary treatment program (including physical and psychological support), better information provision, and an easily accessible contact person were expressed.

CONCLUSIONS

The resulting patient journey map shows how patients experienced and interacted with the current healthcare system. Overall, the results show a complex and long healthcare pathway and important themes for healthcare experiences and needs were identified. Future research could focus on the development and implementation of a patient-centered evidence-based clinical pathway optimising experiences and quality of life.

RELEVANCE TO CLINICAL PRACTICE

The visual tool can help health care professionals, policy makers, and researchers improve healthcare provision which is patient-centered and tailored to the preferences of patients with ischemia with non-obstructive coronary arteries.

Non-invasive Imaging in Women With Heart Failure - Diagnosis and Insights Into Disease Mechanisms

PURPOSE OF REVIEW

To summarise the role of different imaging techniques for diagnosis and investigation of heart failure in women.

RECENT FINDINGS

Although sex differences in heart failure are well recognised, and the scope of imaging techniques is expanding, there are currently no specific guidelines for imaging of heart failure in women. Diagnosis and stratification of heart failure is generally performed first line using transthoracic echocardiography. Understanding the aetiology of heart failure is central to ongoing management, and with non-ischaemic causes more common in women, a multimodality approach is generally required using advanced imaging techniques including cardiovascular magnetic resonance imaging, nuclear imaging techniques, and cardiac computed tomography. There are specific considerations for imaging in women including radiation risks and challenges during pregnancy, highlighting the clear unmet need for cardiology and imaging societies to provide imaging guidelines specifically for women with heart failure.

Assessments of microvascular function in organ systems

Microvascular disease plays critical roles in the dysfunction of all organ systems, and there are many methods available to assess the microvasculature. These methods can either assess the target organ directly or assess an easily accessible organ such as the skin or retina so that inferences can be extrapolated to the other systems and/or related diseases. Despite the abundance of exploratory research on some of these modalities and their possible applications, there is a general lack of clinical use. This deficiency is likely due to two main reasons: the need for standardization of protocols to establish a role in clinical practice or the lack of therapies targeted toward microvascular dysfunction. Also, there remain some questions to be answered about the coronary microvasculature, as it is complex, heterogeneous, and difficult to visualize in vivo even with advanced imaging technology. This review will discuss novel approaches that are being used to assess microvasculature health in several key organ systems, and evaluate their clinical utility and scope for further development.

Gender Differences in Patients With Stable Chest Pain

This study sought to investigate gender differences in clinical presentation, presence, and extent of coronary artery disease (CAD), and all-cause mortality in patients with stable chest pain who underwent coronary computed tomography angiography (CCTA). Patients who visited the fast-track outpatient clinic of the Erasmus Medical Center and underwent CCTA were analyzed. Clinical characteristics of chest pain, CAD on CCTA, coronary artery calcium scores, and survival were collected retrospectively and compared between men and women. Logistic regression was used to identify independent risk factors for the presence of CAD and Cox regression for all-cause mortality. In 1,835 included patients, 966 (52.6%) were female. Men and women were similar in age (55 vs 56 years). Compared with men, women had a lower frequency of typical pain (22.8% vs 31.1%, p <0.001), lower prevalence of significant CAD (22.2% vs 38.1%, p <0.001), and lower coronary artery calcium scores (p <0.001). CAD was more prevalent in men than in women with typical pain (67.4% vs 35.9%, p <0.001) and also with nontypical pain (24.9% vs 18.1%, p = 0.002). After adjustment for baseline characteristic, male sex was associated with all-cause mortality (adjusted hazard ratio 1.87, 95% confidence interval 1.25 to 2.80, p = 0.002). The additional risk of mortality because of CAD was similar between men and women. Stratifying by typical and nontypical pain, women again had a better prognosis. Our study identifies gender-related differences in characteristics, CCTA-findings, and outcomes for women compared with men presenting for CCTA with chest pain. Women have less CAD and a better prognosis than men, the clinical implications of which require further study.

The Central Nervous System and Psychosocial Factors in Primary Microvascular Angina

Patients diagnosed with ischemia without obstructive coronary artery disease (INOCA) comprise the group of patients with primary microvascular angina (MVA). The pathophysiology underlying ischemia and angina is multifaceted. Differences in vascular tone, collateralization, environmental and psychosocial factors, pain thresholds, and cardiac innervation seem to contribute to clinical manifestations. There is evidence suggesting potential interactions between the clinical manifestations of MVA and non-cardiac conditions such as abnormal function of the central autonomic network (CAN) in the central nervous system (CNS), pain modulation pathways, and psychological, psychiatric, and social conditions. A few unconventional non-pharmacological and pharmacological techniques targeting these psychosocial conditions and modulating the CNS pathways have been proposed to improve symptoms and quality of life. Most of these unconventional approaches have shown encouraging results. However, these results are overall characterized by low levels of evidence both in observational studies and interventional trials. Awareness of the importance of microvascular dysfunction and MVA is gradually growing in the scientific community. Nonetheless, therapeutic success remains frustratingly low in clinical practice so far. This should promote basic and clinical research in this relevant cardiovascular field investigating, both pharmacological and non-pharmacological interventions. Standardization of definitions, clear pathophysiological-directed inclusion criteria, crossover design, adequate sample size, and mid-term follow-up through multicenter randomized trials are mandatory for future study in this field.

Pressure- and 3D-Derived Coronary Flow Reserve with Hydrostatic Pressure Correction: Comparison with Intracoronary Doppler Measurements

Purpose: To develop a method of coronary flow reserve (CFR) calculation derived from three-dimensional (3D) coronary angiographic parameters and intracoronary pressure data during fractional flow reserve (FFR) measurement. Methods: Altogether 19 coronary arteries of 16 native and 3 stented vessels were reconstructed in 3D. The measured distal intracoronary pressures were corrected to the hydrostatic pressure based on the height differences between the levels of the vessel orifice and the sensor position. Classical fluid dynamic equations were applied to calculate the flow during the resting state and vasodilatation based on morphological data and intracoronary pressure values. 3D-derived coronary flow reserve (CFRp-3D) was defined as the ratio between the calculated hyperemic and the resting flow and was compared to the CFR values simultaneously measured by the Doppler sensor (CFRDoppler). Results: Haemodynamic calculations using the distal coronary pressures corrected for hydrostatic pressures showed a strong correlation between the individual CFRp-3D values and the CFRDoppler measurements (r = 0.89, p < 0.0001). Hydrostatic pressure correction increased the specificity of the method from 46.1% to 92.3% for predicting an abnormal CFRDoppler < 2. Conclusions: CFRp-3D calculation with hydrostatic pressure correction during FFR measurement facilitates a comprehensive hemodynamic assessment, supporting the complex evaluation of macro-and microvascular coronary artery disease.

A Practical Approach to Invasive Testing in Ischemia with No Obstructive Coronary Arteries (INOCA)

Up to 65% of women and approximately 30% of men have ischemia with no obstructive coronary artery disease (CAD; commonly known as INOCA) on invasive coronary angiography performed for stable angina. INOCA can be due to coronary microvascular dysfunction or coronary vasospasm. Despite the absence of obstructive CAD, those with INOCA have an increased risk of all-cause mortality and adverse outcomes, including recurrent angina and cardiovascular events. These patients often undergo repeat testing, including cardiac catheterization, resulting in lifetime healthcare costs that rival those for obstructive CAD. Patients with INOCA often remain undiagnosed and untreated. This review discusses the symptoms and prognosis of INOCA, offers a systematic approach to the diagnostic evaluation of these patients, and summarizes therapeutic management, including tailored therapy according to underlying pathophysiological mechanisms.

The danger of underdiagnosing coronary microvascular disease in women

ABSTRACT

Heart disease is the number one killer of women in the United States. Part of the difficulty with diagnosing heart disease in women is related to a disease process called coronary microvascular disease (CMVD; previously called syndrome X). Also known as nonobstructive coronary artery disease, CMVD is challenging to identify because often there is a lack of convincing evidence of an acute problem during evaluation. In these patients, the epicardial coronary arteries do not have visible blockages, and stress tests often are interpreted as normal or false positive. Therefore, symptomatic patients often are left undiagnosed, frustrated, and at risk of adverse cardiac events. Frequently, the only method of diagnosis is treatment of the symptoms. This information is provided to help advanced practice nurses and other clinicians diagnose and treat CMVD.

Coronary microvascular disease: The "Meeting Point" of Cardiology, Rheumatology and Endocrinology

BACKGROUND

Exertional chest pain/dyspnea or chest pain at rest are the main symptoms of coronary artery disease (CAD), which are traditionally attributed to insufficiency of the epicardial coronary arteries. However, 2/3 of women and 1/3 of men with angina and 10% of patients with acute myocardial infarction have no evidence of epicardial coronary artery stenosis in X-ray coronary angiography. In these cases, coronary microvascular disease (CMD) is the main causative factor.

AIMS

To present the pathophysiology of CMD in Cardiology, Rheumatology and Endocrinology.

MATERIALS-METHODS

The pathophysiology of CMD in Cardiology, Rheumatology and Endocrinology was evaluated. It includes impaired microvascular vasodilatation, which leads to inability of the organism to deal with myocardial oxygen needs and, hence, development of ischemic pain. CMD, observed in inflammatory autoimmune rheumatic and endocrine/metabolic disorders, brings together Cardiology, Rheumatology and Endocrinology. Causative factors include persistent systemic inflammation and endocrine/metabolic abnormalities influencing directly the coronary microvasculature. In the past, the evaluation of microcirculation was feasible only with the use of invasive techniques, such as coronary flow reserve assessment. Currently, the application of advanced imaging modalities, such as cardiovascular magnetic resonance (CMR), can evaluate CMD non-invasively and without ionizing radiation.

RESULTS

CMD may present with a variety of symptoms with 1/3 to 2/3 of them expressed as typical chest pain in effort, more commonly found in women during menopause than in men. Atypical presentation includes chest pain at rest or exertional dyspnea,but post exercise symptoms are not uncommon. The treatment with nitrates is less effective in CMD, because their vasodilator action in coronary micro-circulation is less pronounced than in the epicardial coronary arteries.

DISCUSSION

Although both classic and new medications have been used in the treatment of CMD, there are still many questions regarding both the pathophysiology and the treatment of this disorder. The potential effects of anti-rheumatic and endocrine medications on the evolution of CMD need further evaluation.

CONCLUSION

CMD is a multifactorial disease leading to myocardial ischemia/fibrosis alone or in combination with epicardial coronary artery disease. Endothelial dysfunction/vasospasm, systemic inflammation, and/or neuroendocrine activation may act as causative factors and bring Cardiology, Rheumatology and Endocrinology together. Currently, the application of advanced imaging modalities, and specifically CMR, allows reliable assessment of the extent and severity of CMD. These measurements should not be limited to "pure cardiac patients", as it is known that CMD affects the majority of patients with autoimmune rheumatic and endocrine/metabolic disorders.

Clinical Relevance of Ischemia with Nonobstructive Coronary Arteries According to Coronary Microvascular Dysfunction

Background

In the absence of obstructive coronary stenoses, abnormality of noninvasive stress tests (NIT) in patients with chronic coronary syndromes may indicate myocardial ischemia of nonobstructive coronary arteries (INOCA). The differential prognosis of INOCA according to the presence of coronary microvascular dysfunction (CMD) and incremental prognostic value of CMD with intracoronary physiologic assessment on top of NIT information remains unknown.

Methods and Results

From the international multicenter registry of intracoronary physiologic assessment (ILIAS [Inclusive Invasive Physiological Assessment in Angina Syndromes] registry, N=2322), stable patients with NIT and nonobstructive coronary stenoses with fractional flow reserve >0.80 were selected. INOCA was diagnosed when patients showed positive NIT results. CMD was defined as coronary flow reserve ≤2.5. According to the presence of INOCA and CMD, patients were classified into 4 groups: group 1 (no INOCA nor CMD, n=116); group 2 (only CMD, n=90); group 3 (only INOCA, n=41); and group 4 (both INOCA and CMD, n=40). The primary outcome was major adverse cardiovascular events, a composite of all‐cause death, target vessel myocardial infarction, or clinically driven target vessel revascularization at 5 years. Among 287 patients with nonobstructive coronary stenoses (fractional flow reserve=0.91±0.06), 81 patients (38.2%) were diagnosed with INOCA based on positive NIT. By intracoronary physiologic assessment, 130 patients (45.3%) had CMD. Regardless of the presence of INOCA, patients with CMD showed a significantly lower coronary flow reserve and higher hyperemic microvascular resistance compared with patients without CMD (P<0.001 for all). The cumulative incidence of major adverse cardiovascular events at 5 years were 7.4%, 21.3%, 7.7%, and 34.4% in groups 1 to 4. By documenting CMD (groups 2 and 4), intracoronary physiologic assessment identified patients at a significantly higher risk of major adverse cardiovascular events at 5 years compared with group 1 (group 2: adjusted hazard ratio [HR_adjusted], 2.88; 95% CI, 1.52–7.19; P=0.024; group 4: HR_adjusted, 4.00; 95% CI, 1.41–11.35; P=0.009).

Conclusions

In stable patients with nonobstructive coronary stenoses, a diagnosis of INOCA based only on abnormal NIT did not identify patients with higher risk of long‐term cardiovascular events. Incorporating intracoronary physiologic assessment to NIT information in patients with nonobstructive disease allowed identification of patient subgroups with up to 4‐fold difference in long‐term cardiovascular events.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04485234.

Coronary Microvascular Dysfunction in Patients With Systemic Lupus Erythematosus and Chest Pain

Chest pain is a common symptom in patients with systemic lupus erythematosus, an autoimmune disease that is associated with increased cardiovascular morbidity and mortality. While chest pain mechanisms can be multifactorial and often attributed to non-coronary or non-cardiac cardiac etiologies, emerging evidence suggests that ischemia with no obstructive coronary arteries (INOCA) is a prevalent condition in patients with chest pain and no obstructive coronary artery disease. Coronary microvascular dysfunction is reported in approximately half of SLE patients with suspected INOCA. In this mini review, we highlight the cardiovascular risk assessment, mechanisms of INOCA, and diagnostic approach for patients with SLE and suspected CMD.

Effects of diabetes mellitus on post-intervention coronary physiological assessment derived by quantitative flow ratio in patients with coronary artery disease underwent percutaneous coronary intervention

AIMS

To compare the prognostic implication of post-percutaneous coronary intervention (PCI) quantitative flow ratio (QFR) assessment in patients with and without diabetes enrolled in the all-comers, multicenter, randomized controlled PANDA III trial.

METHODS

All treated vessels in PANDA III trial were retrospectively assessed for post-PCI QFR. Vessels with available post-PCI QFR were further stratified into DM and non-DM cohorts, and prognostic performance of post-PCI QFR was compared in 2 cohorts. The primary outcome was 2-year vessel-oriented composite endpoint (VOCE), defined as composite of vessel-related cardiac death, vessel-related non-procedural myocardial infarction, and ischemia-driven target vessel revascularization.

RESULTS

Of 2,989 treated vessels, 2,227 (74.5%) with available post-PCI QFR were included, while 548 were presence of DM and 1,679 were not. The performance of post-PCI QFR to predict 2-year VOCE were moderate in both DM (area under the curve [AUC] 0.77, 95% confidence interval [CI]: 0.68 to 0.87) and non-DM cohorts (AUC 0.74, 95% CI: 0.67 to 0.82), while between-cohorts AUC difference was not significant (ΔAUC 0.03, P = 0.65). After multivariate adjustment, vessels with suboptimal post-PCI QFR results (≤0.92) were associated with higher risk of 2-year VOCE in both DM (adjusted HR 6.24, 95% CI: 2.40 to 16.2) and non-DM cohorts (adjusted HR 5.92, 95% CI: 3.28 to 10.7) without significant interaction (P for interaction 0.91).

CONCLUSIONS

This study, the first to directly compare clinical value of post-PCI QFR assessments in patients with and without DM, showed that a higher post-PCI QFR value was associated with improved long-term prognosis regardless of the presence of DM. Clinical Trial Registration Information URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02017275.

Coronary Microvascular Angina: A State-of-the-Art Review

Up to 60–70% of patients, undergoing invasive coronary angiography due to angina and demonstrable myocardial ischemia with provocative tests, do not have any obstructive coronary disease. Coronary microvascular angina due to a dysfunction of the coronary microcirculation is the underlying cause in almost 50% of these patients, associated with a bad prognosis and poor quality of life. In recent years, progress has been made in the diagnosis and management of this condition. The aim of this review is to provide an insight into current knowledge of this condition, from current diagnostic methods to the latest treatments.

Plasma Ceramide Levels Are Elevated in Patients With Early Coronary Atherosclerosis and Endothelial Dysfunction

Background

Elevated plasma ceramides are independent predictors of cardiovascular disease and mortality in patients with advanced epicardial coronary artery disease. Our understanding of plasma ceramides in early epicardial coronary artery disease, however, remains limited. We examined the role of plasma ceramides in early coronary atherosclerosis characterized by coronary endothelial dysfunction.

Methods and Results

Participants presenting with chest pain and nonobstructive epicardial coronary artery disease underwent coronary endothelial function. Patients (n=90) demonstrated abnormal coronary endothelial function with acetylcholine (≥20% decrease in coronary artery diameter or ≤50% increase in coronary blood flow). A total of 30 controls had normal coronary endothelial function. Concentrations of plasma ceramide 18:0 (P=0.038), 16:0 (P=0.021), and 24:0 (P=0.019) differed between participants with normal and abnormal coronary endothelial function. Ceramide 24:0 (odds ratio [OR], 2.23 [95% CI, 1.07–4.66]; P=0.033) and 16:0 (OR, 1.91×10⁶ [95% CI, 11.93–3.07×10¹¹]; P=0.018) were independently associated with coronary endothelial dysfunction. Among participants with endothelium‐dependent coronary dysfunction (n=78), ceramides 16:0 (OR, 5.17×10⁵ [95% CI, 2.83–9.44×10¹⁰]; P=0.033), 24:0 (OR, 2.98 [95% CI, 1.27–7.00]; P=0.012), and 24:1/24:0 (OR, 4.39×10⁻⁴ [95% CI, 4×10⁻⁷–0.48]; P=0.030) were more likely to be elevated.

Conclusions

The current study demonstrated an association between increased circulating ceramide levels and coronary endothelial dysfunction in the absence of epicardial coronary artery disease. This study supports the role of plasma ceramides as a potential biomarker or a therapeutic target for early coronary atherosclerosis in humans.

Pathophysiologic Basis and Diagnostic Approaches for Ischemia With Non-obstructive Coronary Arteries: A Literature Review

Ischemia with non-obstructive coronary arteries (INOCA) has gained increasing attention due to its high prevalence, atypical clinical presentations, difficult diagnostic procedures, and poor prognosis. There are two endotypes of INOCA-one is coronary microvascular dysfunction and the other is vasospastic angina. Diagnosis of INOCA lies in evaluating coronary flow reserve, microcirculatory resistance, and vasoreactivity, which is usually obtained via invasive coronary interventional techniques. Non-invasive diagnostic approaches such as echocardiography, single-photon emission computed tomography, cardiac positron emission tomography, and cardiac magnetic resonance imaging are also valuable for assessing coronary blood flow. Some new techniques (e.g., continuous thermodilution and angiography-derived quantitative flow reserve) have been investigated to assist the diagnosis of INOCA. In this review, we aimed to discuss the pathophysiologic basis and contemporary and novel diagnostic approaches for INOCA, to construct a better understanding of INOCA evaluation.

Myocardial perfusion by CMR coronary sinus flow shows sex differences and lowered perfusion at stress in patients with suspected microvascular angina

Background

Methods

Results

Conclusions

Nuclear Cardiology in Women and Underrepresented Minority Populations

PURPOSE OF REVIEW

To outline sex-specific features of coronary artery disease (CAD) that should be considered in the assessment of women, including those from ethnic minority populations with suspected stable ischemic heart disease (IHD). Second, to determine the latest nuclear imaging tools available to assess microvascular CAD.

RECENT FINDINGS

Latest studies indicate that women are more likely to have ischemia with no obstructive coronary arteries (INOCA) and paradoxically have worse outcomes. Therefore, the evaluation of women with suspected IHD should include assessing microvascular and epicardial coronary circulation. The prevalence of CAD is increasing in younger women due to the increased cardiovascular disease (CVD) risk burden. CAD is often underrecognized in these patients. There is increasing recognition that INOCA is not benign and should be accurately diagnosed and managed. Nuclear imaging assesses the full spectrum of CAD from microvascular CAD to multivessel obstructive epicardial CAD. Further research on myocardial blood flow (MBF) assessment with PET MPI is needed.

Coronary Microvascular Disease

Coronary microvascular disease or dysfunction (CMVD) has been associated with adverse cardiovascular outcomes. Despite a growing prevalence, guidelines on definitive treatment are lacking. Proposed mechanisms of endothelial dysfunction and resultant inflammation have been demonstrated as the underlying cause. Imaging modalities such as echocardiography, cardiac MRI, PET, and in some instances CT, have been shown to be useful in diagnosing CMVD mainly through assessment of coronary blood flow. Invasive measurements through thermodilution and pressure sensor-guided Doppler microcatheters have also been utilized. Treatment options are directed at targeting inflammatory pathways and angina. In our review, we highlight the current literature on the background of CMVD, diagnostic modalities, and management of this disease.

Coronary Arterial Function and Disease in Women With No Obstructive Coronary Arteries

Ischemic heart disease (IHD) is the leading cause of mortality in women. While traditional cardiovascular risk factors play an important role in the development of IHD in women, women may experience sex-specific IHD risk factors and pathophysiology, and thus female-specific risk stratification is needed for IHD prevention, diagnosis, and treatment. Emerging data from the past 2 decades have significantly improved the understanding of IHD in women, including mechanisms of ischemia with no obstructive coronary arteries and myocardial infarction with no obstructive coronary arteries. Despite this progress, sex differences in IHD outcomes persist, particularly in young women. This review highlights the contemporary understanding of coronary arterial function and disease in women with no obstructive coronary arteries, including coronary anatomy and physiology, mechanisms of ischemia with no obstructive coronary arteries and myocardial infarction with no obstructive coronary arteries, noninvasive and invasive diagnostic strategies, and management of IHD.

Sex Differences in Myocardial and Vascular Aging

It is well known that cardiovascular disease manifests differently in women and men. The underlying causes of these differences during the aging lifespan are less well understood. Sex differences in cardiac and vascular phenotypes are seen in childhood and tend to track along distinct trajectories related to dimorphism in genetic factors as well as response to risk exposures and hormonal changes during the life course. These differences underlie sex-specific variation in cardiovascular events later in life, including myocardial infarction, heart failure, ischemic stroke, and peripheral vascular disease. With respect to cardiac phenotypes, females have intrinsically smaller body size-adjusted cardiac volumes and they tend to experience greater age-related wall thickening and myocardial stiffening with aging. With respect to vascular phenotypes, sexual dimorphism in both physiology and pathophysiology are also seen, including overt differences in blood pressure trajectories. The majority of sex differences in myocardial and vascular alterations that manifest with aging seem to follow relatively consistent trajectories from the very early to the very later stages of life. This review aims to synthesize recent cardiovascular aging-related research to highlight clinically relevant studies in diverse female and male populations that can inform approaches to improving the diagnosis, management, and prognosis of cardiovascular disease risks in the aging population at large.

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.

Isa WYH. An Evaluation of the Role of Oxidative Stress in Non-Obstructive Coronary Artery Disease

Approximately half of all women presenting to the emergency department with angina chest pain do not have obstructive coronary artery disease (CAD) on coronary angiography. This condition is termed non-obstructive coronary artery disease (NOCAD), and includes ischemia with no obstructive coronary artery disease (INOCA) and myocardial infarction with non-obstructive coronary arteries (MINOCA). Oxidative stress has been reported to be involved in the development and progression of CAD. However, a scarcity of studies has assessed a correlation between oxidative stress and NOCAD. Thus, a literature review was performed of available reports on the role of oxidative stress in NOCAD. Possible mechanisms involved in oxidative stress that may contribute to NOCAD were identified and evaluated. A key finding of this literature review was that oxidative stress caused vasoconstriction and endothelial damage, and this results in coronary microvascular dysfunction and vasospasm, which, in turn, lead to the pathogenesis of NOCAD.

Impact of invasive aortic pulse pressure on coronary microvascular endothelial-independent dysfunction and on mortality in non-obstructive coronary artery disease

Background

Pulse pressure (PP), a raw index of arterial stiffness, is inversely related to coronary microvascular function, even among patients with non-obstructive coronary artery disease (CAD), as per non-invasive studies. We aimed to determine whether invasive aortic PP is associated with coronary microvascular endothelial dysfunction (CMED) and/or coronary microvascular endothelial independent dysfunction (CMEID) in patients with non-obstructed CAD.

Methods

We retrospectively analysed a cohort of 1894 patients (mean age, 51.2 years; 1261 (66.6%) women) who presented with chest pain and non-obstructive CAD (angiographic stenosis <50%); coronary vasoreactivity was assessed in the mid-left anterior descending artery. The patients were classified based on whether aortic PP was high (≥50 mm Hg). CMEID was defined as abnormal coronary flow reserve (<2.5) or hyperaemic myocardial resistance (>2.0 mm Hg/cm/s), CMED was defined as abnormal acetylcholine-induced per cent change of coronary blood flow (≤50%).

Results

Patients with high aortic PP had a higher rate of CMEID than those with low aortic PP (40.9 vs 25.2%, p<0.001). Conversely, aortic PP was not associated with CMED. On multivariate analysis, high aortic PP was associated with CMEID occurrence (OR 1.42, 95% CI 1.13 to 1.78; p=0.003). On follow-up (median, 150 months), all-cause death was more frequent among patients with vs without high aortic PP (20.1% vs 7.3%, log-rank p<0.001) and HR was 2.08 (95% CI 1.34 to 3.32, p=0.002) on multivariate cox regression analysis. Furthermore, among patients with low aortic PP, CMEID was an independent risk factor for all-cause mortality (HR 2.04, 95% CI 1.01 to 4.16, p=0.048).

Conclusion

In patients with non-obstructive CAD, invasive aortic PP was significantly associated with CMEID, but not with CMED. High aortic PP was an independent predictor of all-cause mortality, but CMEID was an independent risk factor in patients with low aortic PP.

Evaluate the Correlation between the TIMI Frame Count, IMR, and CFR in Coronary Microvascular Disease

Objective

To evaluate the correlation between the TIMI frame count, IMR, and CFR in coronary microvascular disease (slow flow phenomenon).

Methods

TFC and IMR were recorded in the nitroglycerin and ATP administration states, and the relationship between TFC, IMR, and CFR in specific states was analyzed.

Results

A total of 41 patients with baseline TFC >25 frames on coronary angiography were enrolled, and nitroglycerin reduced TFC by 50% from baseline in 24 (58.54%) patients; 16 of the remaining 17 patients were able to achieve a 50% reduction in TFC by further intracoronary ATP injection. 10 patients were further tested for IMR, and the results showed significant correlations between baseline TFC and IMR (r = 0.775, P=0.008), TFC and IMR after nitroglycerin (r = 0.875, P=0.001), and the minimal TFC and IMR that could be obtained with nitroglycerin or ATP administration (r = 0.890, P=0.001). There was also a significant correlation between the proportional improvement in TFC and CFR before and after nitroglycerin injection (r = 0.685, P=0.029). In addition, we observed a lower IMR measured after nitroglycerin than after ATP in three patients, suggesting that CMD may be dominated by NO-sensitive vascular such as prearterioles and that an extensive analysis of the target site of CMD may be achieved by stepwise drug administration.

Conclusion

Induction of TFC in different states by a stepwise drug approach may serve as a potential primary screening method for coronary microcirculatory dysfunction, thereby reducing the need for further IMR or CFR testing.

Role of Exercise Treadmill Testing in the Assessment of Coronary Microvascular Disease

OBJECTIVES

The authors aimed to study the sensitivity and specificity of exercise treadmill testing (ETT) in the diagnosis of coronary microvascular disease (CMD), as well as the prognostic implications of ETT results in patients with CMD.

BACKGROUND

ETT is validated to evaluate for flow-limiting coronary artery disease (CAD), however, little is known about its use for evaluating CMD.

METHODS

We retrospectively studied 249 consecutive patients between 2006 and 2016 who underwent ETT and positron emission tomography within 12 months. Patients with obstructive CAD or left ventricular systolic dysfunction were excluded. CMD was defined as a coronary flow reserve <2. Patients were followed for the occurrence of a first major adverse event (composite of death or hospitalization for myocardial infarction or heart failure).

RESULTS

The sensitivity and specificity of a positive ETT to detect CMD were 34.7% (95% CI: 25.4%-45.0%) and 64.9% (95% CI: 56.7%-72.5%), respectively. The specificity of a positive ETT to detect CMD increased to 86.8% (95% CI: 80.3%-91.7%) when only classifying studies with ischemic electrocardiogram changes that lasted at least 1 minute into recovery as positive, although at a cost of lower sensitivity (15.3%; 95% CI: 8.8%-24.0%). Over a median follow-up of 6.9 years (IQR: 5.1-8.2 years), 30 (12.1%) patients met the composite endpoint, including 13 (13.3%) with CMD (n = 98). In patients with CMD, ETT result was not associated with the composite endpoint (P = 0.076).

CONCLUSIONS

Our data suggest limited sensitivity of ETT to detect CMD. However, a positive ETT with ischemic changes that persist at least 1 minute into recovery in the absence of obstructive CAD should raise suspicion for the presence of CMD given a high specificity. Further study is needed with larger patient sample sizes to assess the association between ETT results and outcomes in patients with CMD.

Autologous CD34+ Stem Cell Therapy Increases Coronary Flow Reserve and Reduces Angina in Patients With Coronary Microvascular Dysfunction

BACKGROUND

Coronary microvascular dysfunction results in angina and adverse outcomes in patients with evidence of ischemia and nonobstructive coronary artery disease; however, no specific therapy exists. CD34+ cell therapy increases microvasculature in preclinical models and improves symptoms, exercise tolerance, and mortality in refractory angina patients with obstructive coronary artery disease. The objective of this research was to evaluate the safety, tolerability, and efficacy of intracoronary CD34+ cell therapy in patients with coronary microvascular dysfunction.

METHODS

We conducted a 2-center, 20-participant trial of autologous CD34+ cell therapy (protocol CLBS16-P01; NCT03508609) in patients with ischemia and nonobstructive coronary artery disease with persistent angina and coronary flow reserve ≤2.5. Efficacy measures included coronary flow reserve, angina frequency, Canadian Cardiovascular Society angina class, Seattle Angina Questionnaire, SF-36, and modified Bruce exercise treadmill test obtained at baseline and 6 months after treatment. Autologous CD34+ cells (CLBS16) were mobilized by administration of granulocyte-colony stimulating factor 5µg/kg/day for 5 days and collected by leukapheresis. Participants received a single intracoronary left anterior descending infusion of isolated CD34+ cells in medium that enhances cell function.

RESULTS

Coronary flow reserve improved from 2.08±0.32 at baseline to 2.68±0.79 at 6 months after treatment (P<0.005). Angina frequency decreased (P<0.004), Canadian Cardiovascular Society class improved (P<0.001), and quality of life improved as assessed by the Seattle Angina Questionnaire (P≤0.03, all scales) and SF-36 (P≤0.04, all scales). There were no cell-related serious adverse events.

CONCLUSIONS

In this pilot clinical trial of microvascular angina, patients with ischemia and nonobstructive coronary artery disease receiving intracoronary infusion of CD34+ cell therapy had higher coronary flow reserve, less severe angina, and better quality of life at 6 months. The current study supports a potential therapeutic role for CD34+ cells in patients with microvascular angina. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03508609.

Vasodilator Strain Stress Echocardiography in Suspected Coronary Microvascular Angina

Background: In patients with Ischemia and non-obstructive coronary artery stenosis (INOCA) wall motion is rarely abnormal during stress echocardiography (SE). Our aim was to determine if patients with INOCA and reduced coronary flow velocity reserve (CVFR) have altered cardiac mechanics using two-dimensional speckle-tracking echocardiography (2DSTE) during SE. Methods: In a prospective, multicenter, international study, we recruited 135 patients with INOCA. Overall, we performed high dose (0.84 mg/kg) dipyridamole SE with combined assessment of CVFR and 2DSTE. The population was divided in patients with normal CVFR (>2, group 1, n = 95) and abnormal CVFR (≤2, group 2, n = 35). Clinical and 2DSTE parameters were compared between groups. Results: Feasibility was high for CFVR (98%) and 2DSTE (97%). A total of 130 patients (mean age 63 ± 12 years, 67 women) had complete flow and strain data. The two groups showed similar 2DSTE values at rest. At peak SE, Group 1 patients showed lower global longitudinal strain (p < 0.007), higher mechanical dispersion (p < 0.0005), lower endocardial (p < 0.001), and epicardial (p < 0.0002) layer specific strain. Conclusions: In patients with INOCA, vasodilator SE with simultaneous assessment of CFVR and strain is highly feasible. Coronary microvascular dysfunction is accompanied by an impairment of global and layer-specific deformation indices during stress.

Histologic validation of stress cardiac magnetic resonance T1-mapping techniques for detection of coronary microvascular dysfunction in rabbits

BACKGROUND

To investigate the diagnostic performance of stress cardiac magnetic resonance (CMR) T1-mapping for the detection of coronary microvascular dysfunction (CMD) by correlating microvascular density (MVD) and collagen volume fraction (CVF) with T1 response to adenosine triphosphate (ATP) stress (stress ΔT1) in rabbits.

METHODS

Twenty-four New Zealand white rabbits were randomly divided into the CMD group induced by microembolization spheres (n = 10), sham-operated group (n = 5), and control group (n = 9). All rabbits underwent 3.0 T CMR, both rest and ATP stress T1-maps were obtained, and first-pass perfusion imaging was performed. Stress ΔT1 and myocardial perfusion reserve index (MPRI) were calculated. For the histologic study, each rabbit was sacrificed after CMR scanning. Left ventricular myocardial tissue was stained with Hematoxylin-eosin (H&E), Masson, and CD31, from which MVD and CVF were extracted. Pearson correlation analyses were performed to determine the strength of the association between the stress ΔT1 and both MVD and CVF.

RESULTS

The stress ΔT1 values (CMD, 2.53 ± 0.37% vs. control, 6.00 ± 0.64% vs. Sham, 6.07 ± 0.97%, p < 0.001) and MPRI (CMD, 1.45 ± 0.13 vs. control, 1.94 ± 0.23, vs. sham, 1.89 ± 0.15, p < 0.001) were both lower in CMD rabbits compared with sham-operated and control rabbits. Further, the stress ΔT1 showed a high correlation with CVF (r = -0.806, p < 0.001) and MVD (r = 0.920, p < 0.001).

CONCLUSIONS

Stress T1 response strongly correlates with pathological MVD and CVF, indicating that stress CMR T1 mapping can accurately detect microvascular dysfunction.

Can EAT be an INOCA goalkeeper

Ischemia with non-obstructive coronary artery (INOCA) is a blind spot of coronary artery disease (CAD). Such patients are often reassured but offered no specific care, that lead to a heightened risk of adverse cerebrovascular disease (CVD) outcomes. Epicardial adipose tissue (EAT) is proven to correlate independently with CAD and its severity, but it is unknown whether EAT is a specific and sensitive indicator of INOCA. This review focuses on the INOCA epidemiology and related factors, as well as the association between EAT.

[Personalized Therapeutic Concepts in Chronic Coronary Syndromes]

Personalized Therapeutic Concepts in Chronic Coronary Syndromes Abstract. Chronic coronary syndromes (CCS) are related to substantial morbidity and mortality. Myocardial ischemia in CCS is caused by either obstructive or non-obstructive alterations of the coronary arteries, including both morphological and functional changes of epicardial vessels and the coronary microvasculature. Diagnostic algorithms of patients with suspected CCS include non-invasive and invasive imaging and functional testing. Therapeutic management comprises lifestyle changes, optimal medical therapy, and coronary revascularization when indicated. This review summarizes the contemporary management of patients with CCS, focusing on the role of invasive assessment and treatment.

Coronary microvascular dysfunction as a chronic inflammatory state: Is there a role for omega-3 fatty acid treatment?

Coronary microvascular dysfunction is a ubiquitous pathologic process that is operational in ischemia with no obstructive coronary artery disease and other cardiovascular disorders including heart failure with preserved ejection fraction. It may, in fact, be a manifestation of a multi-systemic condition of small vessel dysfunction that also affects the brain and kidneys. While the pathophysiology driving coronary microvascular dysfunction is multifactorial, chronic inflammation plays an important role. Resolution of inflammation is an active process mediated, in part, by a family of locally active mediators biosynthesized from omega-3 fatty acids, collectively referred to as specialized pro-resolving mediators. Omega-3 fatty acid treatment modulates inflammation and is associated with improved cardiovascular outcomes and attenuation of plaque progression on cardiovascular imaging. Whether omega-3 fatty acid treatment attenuates coronary microvascular dysfunction is unknown.

Microvascular Angina: Diagnosis and Management

Recognition of suspected ischaemia with no obstructive coronary artery disease – termed INOCA – has increased over the past decades, with a key contributor being microvascular angina. Patients with microvascular angina are at higher risk for major adverse cardiac events including MI, stroke, heart failure with preserved ejection fraction and death but to date there are no clear evidence-based guidelines for diagnosis and treatment. Recently, the Coronary Vasomotion Disorders International Study Group proposed standardised criteria for diagnosis of microvascular angina using invasive and non-invasive approaches. The management strategy for remains empirical, largely due to the lack of high-levelevidence- based guidelines and clinical trials. In this review, the authors will illustrate the updated approach to diagnosis of microvascular angina and address evidence-based pharmacological and non-pharmacological treatments for patients with the condition.

IMPROvE-CED Trial: Intracoronary Autologous CD34+ Cell Therapy for Treatment of Coronary Endothelial Dysfunction in Patients With Angina and Non-Obstructive Coronary Arteries

Background: Coronary endothelial dysfunction (CED) causes angina/ischemia in patients with no-obstructive CAD (NOCAD). Patients with CED have decreased number and function of CD34+ cells involved in normal vascular repair with microcirculatory regenerative potential and paracrine anti-inflammatory effects. We evaluated safety and potential efficacy of intracoronary (IC) autologous CD34+ cell therapy for CED.

Methods: Twenty NOCAD patients with invasively-diagnosed CED and persistent angina despite maximally-tolerated medical therapy (MTMT) underwent baseline exercise stress test (EST), GCSF-mediated CD34+ cell-mobilization, leukapheresis, and selective 1x105 CD34+ cells/kg infusion into LAD. Invasive CED evaluation and EST were repeated 6-months after cell infusion. Primary endpoints were safety and effect of IC autologous CD34+ cell therapy on CED at 6-months follow-up. Secondary endpoints were change in CCS angina class, as-needed sublingual nitroglycerin use/day, Seattle Angina Questionnaire (SAQ) scores, and exercise time at 6-months. Change in CED was compared to that of 51 historic-control NOCAD patients treated with MTMT alone.

Results: Mean age was 52{plus minus}13 years, 75% women. No death, myocardial infarction, or stroke occurred. IC CD34+ cell infusion improved microvascular CED [% acetylcholine-mediated coronary blood flow increased from 7.2 (-18.0-32.4) to 57.6 (16.3-98.3) %, p=0.014], decreased CCS angina class (3.7{plus minus}0.5 to 1.7{plus minus}0.9, Wilcoxon signed-rank test p=0.00018) and sublingual nitroglycerin use/day [1 (0.4-3.5) to 0 (0-1), Wilcoxon signed-rank test p=0.00047], and improved all SAQ scores with no significant change in exercise time at 6-months follow-up. Historic-control patients had no significant change in CED.

Conclusion: A single IC autologous CD34+ cell infusion was safe and may potentially be an effective disease-modifying therapy for microvascular CED in humans. Clinical Trial Registration: NCT03471611

Gender-Related Differences in Chest Pain Syndromes in the Frontiers in CV Medicine Special Issue: Sex & Gender in CV Medicine

Coronary artery disease (CAD) is the leading cause of morbidity and mortality among both women and men, yet women continue to have delays in diagnosis and treatment. The lack of recognition of sex-specific biological and socio-cultural gender-related differences in chest pain presentation of CAD may, in part, explain these disparities. Sex and gender differences in pain mechanisms including psychological susceptibility, the autonomic nervous system (ANS) reactivity, and visceral innervation likely contribute to chest pain differences. CAD risk scores and typical/atypical angina characterization no longer appear relevant and should not be used in women and men. Women more often have ischemia with no obstructive CAD (INOCA) and myocardial infarction, contributing to diagnostic and therapeutic equipoise. Existing knowledge demonstrates that chest pain often does not relate to obstructive CAD, suggesting a more thoughtful approach to percutaneous coronary intervention (PCI) and medical therapy for chest pain in stable obstructive CAD. Emerging knowledge regarding the central and ANS and visceral pain processing in patients with and without angina offers explanatory mechanisms for chest pain and should be investigated with interdisciplinary teams of cardiologists, neuroscientists, bio-behavioral experts, and pain specialists. Improved understanding of sex and gender differences in chest pain, including biological pathways as well as sociocultural contributions, is needed to improve clinical care in both women and men.

Endothelium in Coronary Macrovascular and Microvascular Diseases

ABSTRACT

The endothelium plays a pivotal role in the regulation of vascular tone by synthesizing and liberating endothelium-derived relaxing factors inclusive of vasodilator prostaglandins (eg, prostacyclin), nitric oxide (NO), and endothelium-dependent hyperpolarization factors in a distinct blood vessel size-dependent manner. Large conduit arteries are predominantly regulated by NO and small resistance arteries by endothelium-dependent hyperpolarization factors. Accumulating evidence over the past few decades has demonstrated that endothelial dysfunction and coronary vasomotion abnormalities play crucial roles in the pathogenesis of various cardiovascular diseases. Structural and functional alterations of the coronary microvasculature have been coined as coronary microvascular dysfunction (CMD), which is highly prevalent and associated with adverse clinical outcomes in many clinical settings. The major mechanisms of coronary vasomotion abnormalities include enhanced coronary vasoconstrictive reactivity at epicardial and microvascular levels, impaired endothelium-dependent and endothelium-independent coronary vasodilator capacities, and elevated coronary microvascular resistance caused by structural factors. Recent experimental and clinical research has highlighted CMD as the systemic small artery disease beyond the heart, emerging modulators of vascular functions, novel insights into the pathogenesis of cardiovascular diseases associated with CMD, and potential therapeutic interventions to CMD with major clinical implications. In this article, we will summarize the current knowledge on the endothelial modulation of vascular tone and the pathogenesis of coronary macrovascular and microvascular diseases from bench to bedside, with a special emphasis placed on the mechanisms and clinical implications of CMD.

A pathophysiological compass to personalize antianginal drug treatment

Myocardial ischaemia results from coronary macrovascular or microvascular dysfunction compromising the supply of oxygen and nutrients to the myocardium. The underlying pathophysiological processes are manifold and encompass atherosclerosis of epicardial coronary arteries, vasospasm of large or small vessels and microvascular dysfunction - the clinical relevance of which is increasingly being appreciated. Myocardial ischaemia can have a broad spectrum of clinical manifestations, together denoted as chronic coronary syndromes. The most common antianginal medications relieve symptoms by eliciting coronary vasodilatation and modulating the determinants of myocardial oxygen consumption, that is, heart rate, myocardial wall stress and ventricular contractility. In addition, cardiac substrate metabolism can be altered to alleviate ischaemia by modulating the efficiency of myocardial oxygen use. Although a universal agreement exists on the prognostic importance of lifestyle interventions and event prevention with aspirin and statin therapy, the optimal antianginal treatment for patients with chronic coronary syndromes is less well defined. The 2019 guidelines of the ESC recommend a personalized approach, in which antianginal medications are tailored towards an individual patient's comorbidities and haemodynamic profile. Although no antianginal medication improves survival, their efficacy for reducing symptoms profoundly depends on the underlying mechanism of the angina. In this Review, we provide clinicians with a rationale for when to use which compound or combination of drugs on the basis of the pathophysiology of the angina and the mode of action of antianginal medications.

Vasomotor Dysfunction in Patients with Ischemia and Non-Obstructive Coronary Artery Disease: Current Diagnostic and Therapeutic Strategies

Many patients who present with symptoms or objective evidence of ischemia have no or non-physiologically-significant disease on invasive coronary angiography. The diagnosis of ischemic heart disease is thus often dismissed, and patients receive false reassurance or other diagnoses are pursued. We now know that a significant proportion of these patients have coronary microvascular dysfunction and/or vasospastic disease as the underlying pathophysiology of their clinical presentation. Making the correct diagnosis of such abnormalities is important not only because they impact the quality of life, with recurring symptoms and unnecessary repeated testing, but also because they increase the risk for adverse cardiovascular events. The mainstay of diagnosis remains an invasive comprehensive physiologic assessment, which further allows stratifying these patients into appropriate “endotypes”. It has been shown that tailoring treatment to the patient’s assigned endotype improves symptoms and quality of life. In addition to the conventional drugs used in chronic stable angina, multiple newer agents are being investigated. Moreover, innovative non-pharmacologic and interventional therapies are emerging to provide a bail-out in refractory cases. Many of these novel therapies fail to show consistent benefits, but others show quite promising results.

Outpatient Management of Patients With Angina With No Obstructive Coronary Arteries: How to Come to a Proper Diagnosis and Therapy

Two-thirds of women and one-third of men who undergo a clinically indicated coronary angiography for stable angina, have no obstructive coronary artery disease (CAD). Coronary vascular dysfunction is a highly prevalent underlying cause of angina in these so called “Angina with No Obstructive Coronary Arteries (ANOCA)” patients, foremost in middle aged women. Coronary vascular dysfunction encompasses various endotypes, namely epicardial and microvascular coronary spasms, impaired vasodilatation, and increased microvascular resistance. ANOCA patients, especially those with underlying coronary vascular dysfunction, have an adverse cardiovascular prognosis, poor physical functioning, and a reduced quality of life. Since standard ischemia detection tests and coronary angiograms are not designed to diagnose coronary vascular dysfunction, this ischemic heart disease is often overlooked and hence undertreated. But adequate diagnosis is vital, so that treatment can be started to reduce symptoms, reduce healthcare costs and improve quality of life and cardiovascular prognosis. The purpose of this review is to give a contemporary overview of ANOCA with focus on coronary vascular dysfunction. We will provide a possible work-up of patients suspected of coronary vascular dysfunction in the outpatient clinical setting, based on the latest scientific insights and international consensus documents. We will discuss the value of ischemia detection testing, and non-invasive and invasive methods to diagnose coronary vascular dysfunction. Furthermore, we will go into pharmacological and non-pharmacological therapeutic options including anti-anginal regimens and lifestyle interventions.

The Role of Mental Stress in Ischaemia with No Obstructive Coronary Artery Disease and Coronary Vasomotor Disorders

Ischaemic heart disease has been estimated to affect 126.5 million people globally. Approximately 70% of patients with angina and suspected myocardial ischaemia show no signs of obstructed coronary arteries after coronary angiography, but may still demonstrate ischaemia. Ischaemia with no obstructive coronary artery disease (INOCA) is increasingly acknowledged as a serious condition because of its association with poor quality of life and elevated risk for cardiovascular events. The negative effects of psychological stress on INOCA are gaining more attention. Psychological stress is associated with adverse cardiovascular outcomes such as mental stress-induced myocardial ischaemia. Psychological stress includes anxiety, depression, anger and personality disturbances. Coronary microvascular dysfunction and coronary arterial spasm are phenotypes of coronary vasomotor disorders that are triggered by psychological distress and depression, thereby increasing cardiovascular disease risk. Coronary vasomotor disorders are often co-existent in INOCA patients and might be considered as a contributing factor to mental stress-associated adverse cardiovascular outcomes. Additionally, psychological stress induces endothelial dysfunction more often in (young) women with INOCA than in men. Overall, many studies demonstrate an association between mental stress, coronary microvascular dysfunction and coronary vasospasm in patients with INOCA - especially women. Future research on stress-reducing therapies that target coronary vasomotor disorders in patients with INOCA is needed. This is particularly the case in young adolescents, in whom this type of ischaemic heart disease is increasing.

Sex Differences in Coronary Function Test Results in Patient With Angina and Nonobstructive Disease

Introduction: Invasive coronary function testing (CFT) has become the recommended diagnostic tool to assess the various endotypes of coronary vasomotor dysfunction in patients with angina and no obstructive coronary artery disease (ANOCA), which has implications for therapy and prognosis. Although the expanding performance of CFT is leading to increased knowledge of coronary vasomotor dysfunction, little is known about sex-related differences in the results of comprehensive CFT.

Methods: We conducted a prospective study of all consecutive patients with ANOCA that underwent clinically indicated CFT in a tertiary interventional from February 2019 to February 2021. CFT consisted of acetylcholine testing to diagnose epicardial or microvascular spasm, and adenosine testing to diagnose CMD. CMD was defined as an index of microvascular resistance (IMR) ≥ 25 and/or coronary flow reserve (CFR) < 2.0.

Results: In total, 228 women and 38 men underwent CFT. No differences in traditional risk factors were seen, but women had a higher prevalence of migraine (45 vs. 14%, p = 0.001). Men more often had a history of percutaneous coronary intervention (12 vs. 49%, p = 0.001). We found no difference in clinical presentation. Coronary vasomotor dysfunction was present in 95% of men and 88% of women (p = 0.25), but males show more often epicardial spasm and less microvascular spasm than women (63 vs. 42% and 29 vs. 40% respectively, p = 0.039). Impaired CFR was more prevalent among females (6 vs 20%, p = 0.033). IMR [median of 23 (15–32) vs. 19 (13–25), p = 0.08] did not differ between the sexes.

Conclusion: Men undergoing CFT show a comparable prevalence of coronary vascular dysfunction as women. However, men have a higher prevalence of epicardial spasm and a lower prevalence of microvascular spasm compared with women. An impaired CFR was more often present in women, with an equally impairment of IMR.