Coronary microvascular reactivity is only partially predicted by atherosclerosis risk factors or coronary artery disease in women evaluated for suspected ischemia: results from the NHLBI Women's Ischemia Syndrome Evaluation (WISE)

Coronary microvascular disease in women: epidemiology, mechanisms, evaluation, and treatment

Coronary microvascular dysfunction (CMD) involves functional or structural abnormalities of the coronary microvasculature resulting in dysregulation of coronary blood flow (CBF) in response to myocardial oxygen demand. This perfusion mismatch causes myocardial ischemia, which manifests in patients as microvascular angina (MVA). CMD can be diagnosed non-invasively via multiple imaging techniques or invasively using coronary function testing (CFT), which assists in determining the specific mechanisms involving endothelium-independent and dependent epicardial and microcirculation domains. Unlike traditional coronary artery disease (CAD), CMD can often occur in patients without obstructive atherosclerotic epicardial disease, which can make the diagnosis of CMD difficult. Moreover, MVA due to CMD is more prevalent in women and carries increased risk of future cardiovascular events. Successful treatment of symptomatic CMD is often patient-specific risk factor and endotype targeted. This article aims to review newly identified mechanisms and novel treatment strategies for managing CMD, and outline sex-specific differences in the presentation and pathophysiology of the disease.

ANOCA updated: From pathophysiology to modern clinical practice

Lately, a large number of stable ischemic patients, with no obstructed coronary arteries are being diagnosed. Despite this condition, which is being described as angina with no obstructive coronary arteries (ANOCA), was thought to be benign, recent evidence report that it is associated with increased risk for adverse cardiovascular outcomes. ANOCA is more frequent in women and, pathophysiologically, it is predominantly related with microvascular dysfunction, while other factors, such as endothelial dysfunction, inflammation and autonomic nervous system seem to also play a major role to its development, while other studies implicate ANOCA and microvascular dysfunction in the pathogenesis of heart failure with preserved ejection fraction. For establishing an ANOCA diagnosis, measurement including coronary flow reserve (CFR), microvascular resistance (IMR) and hyperemic microvascular resistance (HMR) are mostly used in clinical practice. In addition, new modalities, such as optical coherence tomography (OCT) are being tested and show promising results for future diagnostic use. Regarding management, pharmacotherapy consists of a wide selection of drugs, according to the respected pathophysiology of the disease (vasospastic angina or microvascular dysfunction), while research for new treatment options including interventional techniques, is currently ongoing. This review, therefore, aims to provide a comprehensive analysis of all aspects related to ANOCA, from pathophysiology to clinical managements, as well as clinical implications and suggestions for future research efforts, which will help advance our understanding of the syndrome and establish more, evidence-based, therapies.

Novel diagnostic approaches and management of coronary microvascular dysfunction

The mechanism underlying ischaemic heart disease (IHD) has been primarily attributed to obstructive coronary artery disease (CAD). However, non-obstructive coronary arteries are identified in >50% of patients undergoing elective coronary angiography, recently leading to growing interest in the investigation and management of angina/ischaemia with non-obstructive coronary arteries (ANOCA/INOCA). INOCA is an umbrella term encompassing a multiple spectrum of possible pathogenetic entities, including coronary vasomotor disorders which consist of two major endotypes: coronary microvascular dysfunction (CMD) and vasospastic angina. Both conditions can coexist and be associated with concomitant obstructive CAD. Particularly, CMD refers to myocardial ischaemia due to reduced vasodilatory capacity of coronary microcirculation secondary to structural remodelling or impaired resting microvascular tone (functional) or a combination of both. CMD is not a benign condition and is more prevalent in women presenting with chronic coronary syndrome compared to men. In this setting, an impaired coronary flow reserve has been associated with increased risk of major adverse cardiovascular events. ANOCA/INOCA patients also experience impaired quality of life and associated increased healthcare costs. Therefore, research in this scenario has led to better definition, classification, and prognostic stratification based on the underlying pathophysiological mechanisms. The development and validation of non-invasive imaging modalities, invasive coronary vasomotor function testing and angiography-derived indices provide a comprehensive characterisation of CMD. The present narrative review aims to summarise current data relating to the diagnostic approach to CMD and provides details on the sequence that therapeutic management should follow.

Evaluating Ischemic Heart Disease in Women: Focus on Angina With Nonobstructive Coronary Arteries (ANOCA)

Ischemic heart disease (IHD) is common in women, and cardiovascular disease is a leading cause of morbidity and mortality. While obstructive coronary artery disease is the most common form of IHD, millions of women suffer from angina with nonobstructive coronary arteries (ANOCA), an umbrella term encompassing multiple nonatherosclerotic disorders of the coronary tree. The underlying pathology leading to ischemia in these syndromes may be challenging to diagnose, leaving many women without a diagnosis despite persistent symptoms that impact quality of life and adversely affect long-term cardiovascular prognosis. In the last decade, there have been significant advances in the recognition and diagnostic evaluation of ANOCA. Despite these advances, the standard approach to evaluating suspected IHD in women continues to focus predominantly on the assessment of atherosclerotic coronary artery disease, leading to missed opportunities to accurately diagnose and treat underlying coronary vasomotor disorders. The goal of this review is to describe advances in diagnostic testing that can be used to evaluate angina in women and present a pragmatic diagnostic algorithm to guide evaluation of ANOCA in symptomatic patients. The proposed approach for the assessment of ANOCA is consistent with prior expert consensus documents and guidelines but is predicated on the medical interview and pretest probability of disease to inform a personalized diagnostic strategy.

Ischaemia with no obstructive coronary arteries: a review with focus on the Asian population

ABSTRACT

Ischaemia with no obstructive coronary arteries (INOCA) has been a diagnostic and therapeutic challenge for decades. Several studies have demonstrated that INOCA is associated with an increased risk of death, adverse cardiovascular events, poor quality of life and high healthcare cost. Although there is increasing recognition of this entity in the Western population, in the Asian population, INOCA remains elusive and its prevalence uncertain. Despite its prognostic significance, diagnosis of INOCA is often delayed. In this review, we identified the multiple barriers to its diagnosis and management, and proposed strategies to overcome them.

Smoking and Respiratory Diseases in Patients with Coronary Microvascular Dysfunction

BACKGROUND

Coronary microvascular disease (CMD) is common in patients with and without obstructive coronary artery disease, and is associated with adverse clinical outcomes. Respiratory-related variables are associated with pulmonary and systemic microvascular dysfunction, while evidence about their relationship with CMD is limited. We aim to evaluate respiratory-related variables as risk factors of CMD.

METHODS

This is an observational, single-center study enrolling consecutive patients undergoing invasive evaluation of coronary microvascular function in the catheterization laboratory. Patients with evidence of obstructive coronary artery disease or with missing data were excluded. Associations between respiratory-related variables and indices of CMD were assessed using univariate and multivariate regression models.

RESULTS

Overall, 266 patients (mean age 67 ± 11 years, 59% females) were included in the current analysis. Of those, 155 (58%) had evidence of CMD. Among the respiratory variables, independent predictors of CMD were current smoking (adjusted odds ratio [AOR] 2.5; 95% confidence interval [CI], 1.2-5; P = .01) and obstructive sleep apnea (AOR 5.7; 95% CI, 1.2-26; P = .03), while chronic obstructive pulmonary disease was not. Among ever-smokers, higher smoking pack-years was an independent risk factor for CMD (median 35 vs 25 pack-years, AOR 1.09; 95% CI, 1.04-1.13; P < .01), and was associated with higher rates of pathologic index of microcirculatory resistance and resistive reserve ratio.

CONCLUSION

In patients undergoing invasive coronary microvascular evaluation, current smoking and obstructive sleep apnea are independently associated with CMD. Among smokers, higher pack-years is a strong predictor for CMD. Our findings should raise awareness for prevention and possible treatment options.

Nonobstructive epicardial coronary artery disease: an evolving concept in need of diagnostic and therapeutic guidance

For decades, we have been treating patients presenting with angina and concerning electrocardiographic changes indicative of ischemia or injury, in whom no culprit epicardial coronary stenosis was found during diagnostic coronary angiography. Unfortunately, the clinical outcomes of these patients were not better than those with recognized obstructive coronary disease. Improvements in technology have allowed us to better characterize these patients. Consequently, an increasing number of patients with ischemia and no obstructive coronary artery disease (INOCA) or myocardial infarction in the absence of coronary artery disease (MINOCA) have now gained formal recognition and are more commonly encountered in clinical practice. Although both entities might share functional similarities at their core, they pose significant diagnostic and therapeutic challenges. Unless we become more proficient in identifying these patients, particularly those at higher risk, morbidity and mortality outcomes will not improve. Though this field remains in constant flux, data continue to become available. Therefore, we thought it would be useful to highlight important milestones that have been recognized so we can all learn about these clinical entities. Despite all the progress made regarding INOCA and MINOCA, many important knowledge gaps continue to exist. For the time being, prompt identification and early diagnosis remain crucial in managing these patients. Even though we are still not clear whether intensive medical therapy alters clinical outcomes, we remain vigilant and wait for more data.

Traditional Cardiovascular Risk Factors and Coronary Microvascular Dysfunction in Women and Men: A Single-Center Study

INTRODUCTION

Coronary microvascular dysfunction (CMD) is common in patients with and without obstructive epicardial coronary artery disease (CAD). Risk factors for the development of CMD have not been fully elucidated, and data regarding sex-associated differences in traditional cardiovascular risk factors for obstructive CAD in patients with CMD are lacking.

METHODS

In this single-center, prospective registry, we enrolled patients with nonobstructive CAD undergoing clinically indicated invasive assessment of coronary microvascular function between November 2019 and March 2023. Associations between coronary microvascular dysfunction, traditional cardiovascular risk factors, and sex were assessed using univariate and multivariate regression models.

RESULTS

Overall, 245 patients with nonobstructive CAD were included in the analysis (62.9% female; median age 68 (interquartile range: 59, 75). Microvascular dysfunction was diagnosed in 141 patients (57.5%). The prevalence of microvascular dysfunction was similar in women and men (59.0% vs. 57.0%; p = 0.77). No association was found between traditional risk factors for coronary atherosclerosis and CMD regardless of whether CMD was structural or functional. In women, but not in men, older age and the presence of previous ischemic heart disease were associated with lower coronary flow reserve (β = -0.29; p < 0.01 and β = -0.15; p = 0.05, respectively) and lower resistive reserve ratio (β = -0.28; p < 0.01 and β = -0.17; p = 0.04, respectively).

CONCLUSION

For the entire population, no association was found between coronary microvascular dysfunction and traditional risk factors for coronary atherosclerosis. In women only, older age and previous ischemic heart disease were associated with coronary microvascular dysfunction. Larger studies are needed to elucidate risk factors for CMD.

Recurrent syncope due to ischemia with non-obstructive coronary artery disease: a case report

BACKGROUND

Ischemia with non-obstructive coronary artery disease is a prevalent form of ischemic heart disease. The majority of ischemia with non-obstructive coronary artery disease cases are attributed to underlying factors such as coronary microvascular dysfunction (CMD) and/or coronary artery spasm. Ischemia with non-obstructive coronary artery disease can present with various clinical manifestations. Recurrent syncope is an atypical complaint in patients with ischemia with non-obstructive coronary artery disease.

CASE PRESENTATION

This case report describes the presentation of a 58-year-old Chinese male patient who experienced repeated episodes of syncope. The syncope was found to be caused by concomitant coronary artery spasm and presumptive coronary microvascular dysfunctionc suggested by "slow flow" on coronary angiography. The patient was prescribed diltiazem sustained-release capsules, nicorandil, and atorvastatin. During the three-month follow-up conducted on our outpatient basis, the patient did not experience a recurrence of syncope.

CONCLUSION

This study highlights the importance of considering ischemia with non-obstructive coronary artery disease as a potential cause of syncope in the differential diagnosis. It emphasizes the need for early diagnosis of ischemia with non-obstructive coronary artery disease to facilitate more effective management strategies.

Sex differences in diagnostic modalities of coronary artery disease: Evidence from coronary microcirculation

Although atherosclerosis is usually considered a disease of the large arteries, risk factors for atherosclerosis also trigger structural and functional abnormalities at a microvascular level. In cardiac disease, microvascular dysfunction is especially relevant in women, among whom the manifestation of ischemic disease due to impaired coronary microcirculation is more common than in men. This sex-specific clinical phenotype has important clinical implications and, given the higher pre-test probability of coronary microvascular dysfunction in females, different diagnostic modalities should be used in women compared to men. In this review, we summarize invasive and non-invasive diagnostic modalities to assess coronary microvascular function, ranging from catheter-based evaluation of endothelial function to Doppler echocardiography and positron emission tomography. Moreover, we discuss different clinical settings in which microvascular disease plays an important role, underlining the importance of choosing the right diagnostic modality depending on the sex of the patients.

Coronary Microvascular Dysfunction: What Clinicians and Investigators Should Know

PURPOSE OF REVIEW

Abnormal structure and function of the coronary microvasculature have been implicated in the pathophysiology of multiple cardiovascular disease processes. This article reviews recent research progress related to coronary microvascular dysfunction (CMD) and salient clinical takeaways.

RECENT FINDINGS

CMD is prevalent in patients with signs and symptoms of ischemia and no obstructive epicardial coronary artery disease (INOCA), particularly in women. CMD is associated with adverse outcomes, including most frequently the development of heart failure with preserved ejection fraction. It is also associated with adverse outcomes in patient populations including hypertrophic cardiomyopathy, dilated cardiomyopathy, and acute coronary syndromes. In patients with INOCA, stratified medical therapy guided by invasive coronary function testing to define the subtype of CMD leads to improved symptoms. There are invasive and non-invasive methodologies to diagnose CMD that provide prognostic information and mechanistic information to direct treatment. Available treatments improve symptoms and myocardial blood flow; ongoing investigations aim to develop therapy to improve adverse outcomes related to CMD.

Factors Associated with Impaired Resistive Reserve Ratio and Microvascular Resistance Reserve

Coronary microvascular dysfunction (CMD) is described as an important subset of ischemia with no obstructive coronary artery disease. Resistive reserve ratio (RRR) and microvascular resistance reserve (MRR) have been proposed as novel physiological indices evaluating coronary microvascular dilation function. The aim of this study was to explore factors associated with impaired RRR and MRR. Coronary physiological indices were invasively evaluated in the left anterior descending coronary artery using the thermodilution method in patients suspected of CMD. CMD was defined as a coronary flow reserve <2.0 and/or index of microcirculatory resistance ≥25. Of 117 patients, 26 (24.1%) had CMD. RRR (3.1 ± 1.9 vs. 6.2 ± 3.2, p < 0.001) and MRR (3.4 ± 1.9 vs. 6.9 ± 3.5, p < 0.001) were lower in the CMD group. In the receiver operating characteristic curve analysis, RRR (area under the curve 0.84, p < 0.001) and MRR (area under the curve 0.85, p < 0.001) were both predictive of the presence of CMD. In the multivariable analysis, previous myocardial infarction, lower hemoglobin, higher brain natriuretic peptide levels, and intracoronary nicorandil were identified as factors associated with lower RRR and MRR. In conclusion, the presence of previous myocardial infarction, anemia, and heart failure was associated with impaired coronary microvascular dilation function. RRR and MRR may be useful to identify patients with CMD.

Latest from the WISE: Contributions to the Understanding of Ischemia and Heart Failure among Women with No Obstructive Coronary Arteries

Since 1996, the National Heart, Lung, and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation (WISE) has been investigating pathophysiological processes underlying ischemic heart disease in women and related outcomes. Recent findings have focused on women with signs and symptoms of ischemia and no obstructive coronary arteries (INOCA) and their elevated risk for heart failure with preserved ejection fraction (HFpEF). This review summarizes the latest WISE findings related to INOCA and pre-HFpEF characteristics, addressing our understanding of contributions from traditional vs nontraditional risk factors in women.

Clinical and psychological characteristics of patients with ischemia and non-obstructive coronary arteries (INOCA) and obstructive coronary artery disease

Study objective

Ischemia with non-obstructive coronary arteries (INOCA) is caused by vascular dysfunctions and predominantly seen in women. For better recognition and prevention more insight is needed on risk factors and well-being. We aimed to explore differences in psychological distress, quality of life, risk factors, and medication use between women with INOCA and obstructive coronary artery disease (CAD).

Methods

Patients from two separate studies (n = 373, 57 % women) completed a questionnaire assessing psychological and clinical factors. Analyses were performed for women only who were categorized into three groups: non-ischemic chest pain (n = 115), INOCA (n = 68), and obstructive CAD (n = 30). Secondary analyses were performed for men only, and sex differences within INOCA patients were explored.

Results and conclusion

Compared to obstructive CAD patients, INOCA patients reported better physical functioning (p = 0.041). Furthermore, INOCA patients had less often hypercholesterolemia (p < 0.001), were less often active smokers (p = 0.062), had a lower mean BMI (p = 0.022), and reported more often a familial history of CAD (p = 0.004). Patients with INOCA used antithrombotic, cholesterol lowering medications, and beta-blockers less often than patients with obstructive CAD. No differences between patients with INOCA and obstructive CAD were found for psychological distress, well-being, and for women-specific risk factors. The results suggest that women with INOCA experience similar levels of psychological distress and seem to have different risk factor profiles and are less optimally treated as compared to obstructive CAD patients. Further research on risk factors is needed for better prevention and treatment.

The Proportion of Circulating CD45RO+CD8+ T Cells is Associated with the Coronary Slow Flow

Background

Circulating memory CD8+ T cells have been shown to be a crucial mediator of chronic inflammation. This study investigated whether the baseline proportion of circulating CD45RO+CD8+ T cells was associated with the coronary slow flow (CSF) phenomenon.

Methods

A total of 160 consecutive patients [mean (standard deviation (SD)) age, 67.86 (9.55) years; 51.25% male] who were admitted to our hospital between August 2020 and October 2020 for chest pain and underwent coronary angiography with the absence of coronary stenosis were enrolled in this cross-sectional analysis. The patients' admission CD45RO+ CD8+ T cell plasma levels were measured using flow cytometry. Angiographic CSF was defined as thrombolysis in myocardial infarction (TIMI) flow of ≤ 2 without coronary stenosis, and non-CSF was defined as coronary arteries (< 50% stenosis) with TIMI 3 flow.

Results

The incidence of angiographic CSF was 22.5%. Patients with angiographic CSF had higher levels of CD45RO+CD8+ T cells than those without CSF [56.18 (13.93) vs. 45.26 (16.45); p < 0.001]. After multivariable adjustment, the risk of incident CSF was 2.41 [95% confidence interval (CI) 1.46-3.97] per SD change in CD45RO+ CD8+ T cells. Further, coronary microvascular resistance was significantly higher in patients with CSF than in those without CSF. A positive linear relationship between CD45RO+CD8+ T cells and coronary microvascular resistance was observed.

Conclusions

The proportion of circulating CD45RO+CD8+ T cells is an independent indicator of CSF. This observation may provide insights into the pathophysiological mechanism of CSF.

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.

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.

Molecular Hallmarks of Ischemia with Non-Obstructive Coronary Arteries: The "INOCA versus Obstructive CCS" Challenge

Up to 4 million patients with signs of myocardial ischemia have no obstructive coronary artery disease (CAD). The absence of precise guidelines for diagnosis and treatment in non-obstructive CAD encourages the scientific community to fill the gap knowledge, to provide non-invasive and less expensive diagnostic tools. The aim of our study was to explore the biological profile of Ischemia with Non-Obstructive Coronary Arteries (INOCA) patients with microvascular dysfunction compared to patients presenting with obstructive chronic coronary syndrome (ObCCS) in order to find specific hallmarks of each clinical condition. We performed a gene expression array from peripheral blood mononuclear cells (PBMCs) isolated from INOCA (n = 18) and ObCCS (n = 20) patients. Our results showed a significantly reduced gene expression of molecules involved in cell adhesion, signaling, vascular motion, and inflammation in INOCA as compared to the ObCCS group. In detail, we found lower expression of Platelet and Endothelial Cell Adhesion Molecule 1 (CD31, p < 0.0001), Intercellular Adhesion Molecule-1 (ICAM1, p = 0.0004), Tumor Necrosis Factor (TNF p = 0.0003), Transferrin Receptor (TFRC, p = 0.002), and Vascular Endothelial Growth Factor A (VEGFA, p = 0.0006) in the INOCA group compared with ObCCS. Meanwhile, we observed an increased expression of Hyaluronidase (HYAL2, p < 0.0001) in INOCA patients in comparison to ObCCS. The distinct expression of molecular biomarkers might allow an early and non-invasive differential diagnosis between ObCCS and INOCA, improving clinical management and treatment options, in the era of personalized medicine.

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

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.

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.

Syndrome of Nonobstructive Coronary Artery Diseases: A Comprehensive Overview of Open Artery Ischemia

Syndromes of cardiac ischemia with nonobstructive coronary arteries have been increasingly recognized as a clinical entity with heterogeneous clinical presentations, commonly encountered in women. Knowledge of pathophysiology and clinical risk factors is key to ensuring appropriate diagnostic evaluation and management for these often-neglected patients. In this review, we discuss the epidemiology, risk factors, and clinical presentations of these syndromes. We provide algorithms for diagnosis and management of these entities based on current scientific knowledge and highlight some of the key knowledge gaps and ongoing trials in this emerging field.

Risk factors for heart failure in women with ischemia and no obstructive coronary artery disease

Study objective

Women with ischemia and no obstructive coronary artery disease (INOCA) are at increased risk for heart failure (HF) hospitalizations, which is predominantly HF with preserved ejection fraction (HFpEF). We aimed to identify predictors for the development of heart failure HF in a deeply phenotyped cohort of women with INOCA and long-term prospective follow-up.

Design setting and participants

Women enrolled in the NHLBI-sponsored Women's Ischemia Syndrome Evaluation (WISE) were evaluated for baseline characteristics including clinical history, medications, physical exam, laboratory data and angiographic data. Using a multivariate Cox analysis, we assessed the association between baseline characteristics and the occurrence of HF hospitalizations in 493 women with evidence of ischemia but no obstructive coronary disease, no prior history of HF, and available follow-up data.

Results

During a median follow-up of 6-years, 18 (3.7%) women were hospitalized for HF. Diabetes mellitus and tobacco use were associated with HF hospitalization. In a multivariate analysis adjusting for known HFpEF predictors including age, diabetes, hypertension, tobacco use, and statin use, novel predictive variables included higher resting heart rate, parity and IL-6 levels and lower coronary flow reserve (CFR) and poor functional status.

Conclusions

There is a considerable incidence of HF hospitalization at longer term follow-up in women with INOCA. In addition to traditional risk factors, novel risk variables that independently predict HF hospitalization include multi-parity, high IL-6, low CFR, and poor functional status. These novel risk factors may be useful to understand mechanistic pathways and future treatment targets for prevention of HFpEF.

Coronary Microvascular Dysfunction: A Practical Approach to Diagnosis and Management

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of diagnostic and treatment considerations in patients with coronary microvascular dysfunction (CMD) in the absence of obstructive coronary artery disease (CAD).

RECENT FINDINGS

The prevalence of obstructive CAD in unselected patient populations referred for evaluation of angina is less than 10%. A significant proportion of patients with angina and no obstructive CAD have CMD, a condition associated with impaired cardiovascular prognosis. Non-invasive and invasive evaluation of coronary microvascular function is feasible and widely available, yet CMD is underdiagnosed and undertreated. A patient-tailored treatment approach guided by coronary microvascular testing shows promising results for patient-reported outcomes of symptom burden and quality of life. Coronary microvascular testing should be considered in angina patients with no obstructive CAD, before other causes of chest pain are explored. A patient-tailored treatment approach guided by a complete evaluation of epicardial anatomy and macro-and microvascular function may help optimize treatment strategy and prevent unnecessary medical interventions. More research is needed to establish the long-term effect of patient-tailored therapies on risk reduction in CMD.

Functional and Economic Impact of INOCA and Influence of Coronary Microvascular Dysfunction

OBJECTIVES

This study sought to better characterize the quality of life and economic impact in patients with symptoms of ischemia and no obstructive coronary disease (INOCA) and to identify the influence of coronary microvascular dysfunction (CMD).

BACKGROUND

Patients with INOCA have a high symptom burden and an increased incidence of major adverse cardiac events. CMD is a frequent cause of INOCA. The morbidity associated with INOCA and CMD has not been well-characterized.

METHODS

Sixty-six patients with INOCA underwent stress cardiac magnetic resonance with calculation of myocardial perfusion reserve (MPR); MPR 2.0 to 2.4 was considered borderline-reduced (possible CMD) and MPR <2.0 was defined as reduced (definite CMD). Subjects completed quality of life questionnaires to assess the morbidity and economic impact of INOCA. Questionnaire results were compared between INOCA patients with and without CMD. In addition, logistic regression was used to determine the predictors of CMD within the INOCA population.

RESULTS

The prevalence of definite CMD was 24%. Definite or borderline CMD was present in 59% (MPR ≤2.4). Patients with INOCA reported greater physical limitation, angina frequency, and reduced quality of life compared to referent stable coronary artery disease and acute myocardial infarction populations. In addition, Patients with INOCA reported frequent time missed from work and work limitations, suggesting a substantial economic impact. No difference was observed in reported symptoms between INOCA patients with and without CMD. Glomerular filtration rate and body-mass index were significant predictors of CMD in multivariable regression analysis.

CONCLUSIONS

INOCA is associated with high morbidity similar to other high-risk cardiac populations, and work limitations reported by Patients with INOCA suggest a substantial economic impact. CMD is a common cause of INOCA but is not associated with increased morbidity. These results suggest that there is significant symptom burden in the INOCA population regardless of etiology.

Transthoracic Assessment of Coronary Flow Velocity Reserve: A Practical Approach to Diagnostic Testing in Patients with Angina and No Obstructive Coronary Artery Disease

More than half of the patients with symptoms suggestive of myocardial ischemia presenting at invasive angiography have no obstructive coronary artery disease (CAD). A large proportion of these patients have ischemia caused by coronary microvascular dysfunction, a condition associated with adverse cardiovascular prognosis. Measurement of coronary flow velocity reserve by transthoracic Doppler echocardiography is a feasible and reproducible method for the evaluation of coronary microvascular function. This review provides a practical overview of the method in a clinical setting of angina and noobstructive CAD, including technical details and prognostic significance.

Berries and Their Polyphenols as a Potential Therapy for Coronary Microvascular Dysfunction: A Mini-Review

Ischemia with no obstructive coronary artery disease (INOCA) is a common diagnosis with a higher prevalence in women compared to men. Despite the absence of obstructive coronary artery disease and no structural heart disease, INOCA is associated with major adverse cardiovascular outcomes as well a significant contributor to angina and related disability. A major feature of INOCA is coronary microvascular dysfunction (CMD), which can be detected by non-invasive imaging and invasive coronary physiology assessments in humans. CMD is associated with epicardial endothelial-dependent and -independent dysfunction, diffuse atherosclerosis, and left-ventricular hypertrophy, all of which lead to insufficient blood flow to the myocardium. Inflammatory and oxidative stress signaling, upregulation of the renin-angiotensin-aldosterone system and adrenergic receptor signaling are major drivers of CMD. Treatment of CMD centers around addressing cardiovascular risk factors; however, there are limited treatment options for those who do not respond to traditional anti-anginal therapies. In this review, we highlight the ability of berry-derived polyphenols to modulate those pathways. The evidence supports the need for future clinical trials to investigate the effectiveness of berries and their polyphenols in the treatment of CMD in INOCA patients.

Association of High Density Cholesterol With Hyperemic Epicardial Flow and Frame Count Reserve in Patients With Moderate Coronary Lesions and Slow Coronary Flow

Background

Patients with microvascular angina and non-obstructive coronary atherosclerotic disease have an elevated risk of adverse events and all-cause mortality compared with individuals without ischaemic heart disease. The diagnosis coronary microvascular dysfunction in this setting relies on the detection of impaired coronary flow at rest or on calculation of coronary flow reserve. Previous studies demonstrate that the coronary flow reserve assessed by the corrected thrombolysis in myocardial infarction method - the frame count reserve is an objective quantitative alternative to other widely used invasive methods for microvascular status evaluation.

Purpose

We assessed the significance of clinical, hemodynamic, angiographic variables and therapy with reference to FCR in a small group of patients with up to moderate atherosclerotic coronary lesions and slow coronary flow. Materials and methods: Frame count reserve was evaluated in 15 patients without flow-limiting (>50%) coronary stenoses admitted with unstable angina. Frame count reserve was calculated by dividing the baseline corrected thrombolysis in myocardial infarction frame count (cTFC) by the cTFC assessed after intracoronary infusion of 100 µg of the calcium channel blocker - verapamil.

Results

The values of frame count reserve correlate positively with the levels of high density cholesterol (r= 0.900, p=0.001), inversely coronary flow after the application of verapamil - cTFCv (r= - 0.534, p=0.049). cTFCv was positively related with the levels of high density lipoproteins (r = - 0.645; p= 0.044) and was negatively influenced by the presence of atherosclerotic lesions at quantitative angiography (42.8±19.1 (n=8) vs 23±5.4 (n=7), p=0.029).The therapy with β-blocker and long-acting nitrate was associated with insignificantly higher frame count reserves after intracoronary verapamil compared to the continuous intake only of β-blocker or β-blocker and verapamil (2.1±0.78 vs 1.34±0.14 vs 1.70±0.70, p=NS).

Conclusions

Higher high-density lipoproteins relate to higher frame count reserves evaluated using verapamil. The improved blood flow after this microvascular vasodilator is consistently positively related to high-density cholesterol and the lack of atherosclerosis at conventional coronary angiography. The combined intake of micro- and macrovascular vasodilator could be associated with higher frame count reserves compared to therapy with β-blocker and one vasodilating drug.

Impaired coronary flow velocity reserve is associated with cardiovascular risk factors but not with angina symptoms

OBJECTIVES

Coronary microvascular dysfunction (CMD) is considered to cause angina pectoris in a large proportion of women with no obstructive coronary artery disease (CAD). However, data supporting a relation between angina pectoris and CMD are limited. We compared CMD in women with angina with asymptomatic women and evaluated the relation between presence of CMD, angina characteristics, cardiovascular risk factors and results of stress testing.

METHODS

In a cross-sectional study, we included 1684 women with angina and <50% coronary artery stenosis on invasive angiography. Asymptomatic women from the community-based Copenhagen City Heart Study served as reference group (n=102). Coronary microvascular function was determined by coronary flow velocity reserve (CFVR) assessed by transthoracic Doppler stress echocardiography. CFVR < 2 was defined as CMD. Symptoms were obtained from standardised angina questionnaires and results of stress testing from health records.

RESULTS

Median CFVR was 2.33 (IQR 2.00-2.75) in symptomatic women versus 2.60 (2.19-2.95) in asymptomatic (p=0.007). CFVR <2 was found in 25% of symptomatic and in 19% of asymptomatic women. Symptomatic women had a greater risk factor burden. After adjusting for age, hypertension, diabetes, smoking and heart rate the difference in CFVR between groups disappeared (p=0.213). We found no associations between CFVR and angina characteristics, symptom burden or results from stress testing.

CONCLUSIONS

Impaired CFVR is more prevalent in symptomatic than in asymptomatic women and related to the cardiovascular risk factors hypertension, diabetes, smoking and increased heart rate. Neither a positive bicycle test, single photon emission CT stress test nor chest pain characteristics identify women with impaired CFVR among women with angina and no obstructive CAD. Results may question the concept of microvascular angina as currently defined.

Blood haemoglobin, renal insufficiency, fractional flow reserve and plasma NT-proBNP is associated with index of microcirculatory resistance in chronic coronary syndrome

BACKGROUND

Coronary microvascular dysfunction (CMVD) is associated with adverse cardiovascular outcome. We aimed to determine the prevalence of CMVD and factors related to index of microcirculatory resistance (IMR) in consecutive patients with chronic coronary syndrome (CCS) undergoing elective coronary angiography.

METHODS AND RESULTS

Non-interventional physicians enrolled 274 patients with CCS before angiography, to minimize selection bias by PCI-operators. Fractional flow reserve (FFR) and IMR were measured in the LAD. Subjects with extensively diseased LAD, no measures due to technical reasons or violation of protocol were excluded from the analysis (n = 54). The proportion of patients with IMR corrected for collateral flow (IMR_corr) >25 units was 25% (95% confidence interval [CI] 19%-31%) in all 220 patients. In subjects with FFR ≤0.80 in the LAD the proportion of IMR_corr > 25 units was 21% (95% CI 13%-30%) as compared to subjects with FFR >0.80, 29% (95% CI 21%-36%), p = .268. Haemoglobin (p < .005; r2 = 0.084), FFR in the LAD (p = .001; r2 = 0.049), creatinine clearance (p = .001; r² = 0.049; inversely), and NT-proBNP (p = .038; r² = 0.021) were independently associated with IMR_corr in multivariate linear regression analysis.

CONCLUSIONS

We report that IMR_corr is associated with renal dysfunction, NT-proBNP, FFR in the LAD and, for the first time, blood haemoglobin. One in four of patients referred for coronary angiography due to CCS have CMVD defined as IMR_corr > 25 in the LAD.

Coronary Microvascular Dysfunction

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

Ischaemia with no obstructive coronary arteries

Ischaemia with no obstructive coronary arteries (INOCA) is a common ischaemic heart disease with a female preponderance, mostly due to underlying coronary vascular dysfunction comprising coronary microvascular dysfunction and/or epicardial coronary vasospasm. Since standard ischaemia detection tests and coronary angiograms are not suitable to diagnose coronary vascular dysfunction, INOCA is often overlooked in current cardiology practice. Future research, including large outcome trials, is much awaited. Yet, adequate diagnosis is possible and treatment options are available and vital to reduce symptoms and most probably improve cardiovascular prognosis. This review intends to give a brief overview of the clinical presentation, underlying pathophysiology, and the diagnostic and treatment options in patients with suspected INOCA.

Five-Year Follow-Up of Coronary Microvascular Dysfunction and Coronary Artery Disease in Systemic Lupus Erythematosus: Results From a Community-Based Lupus Cohort

OBJECTIVE

The present study was undertaken to investigate prospective change in the prevalence of coronary microvascular dysfunction (CMD) and obstructive coronary artery disease (CAD) in a cohort of subjects with systemic lupus erythematosus (SLE) initially evaluated for anginal chest pain (CP). Prior work documented a relatively high prevalence of CMD in the absence of obstructive CAD in subjects with SLE.

METHODS

Twenty female SLE subjects with CP who underwent stress cardiac magnetic resonance imaging (CMRI) and coronary computed tomography angiography at baseline were reevaluated at 5 years.

RESULTS

Seventeen subjects (85%) were available and reenrolled, of which 11 (65%) had persistent CP at follow-up. Fourteen subjects had complete follow-up CMRI, of which 36% (n = 5) demonstrated CMD at follow-up. Further, 25% (1 of 4) of the originally abnormal myocardial perfusion reserve index (MPRI) findings at baseline were lower at follow-up, while 2 additional abnormal MPRI findings at follow-up were noted in previously normal MPRI results. The prevalence of CMD and nonobstructive/obstructive CAD both was unchanged between baseline and follow-up, respectively (both P values not significant). During follow-up, 33% of subjects (5 of 15) had adverse cardiac outcomes, including pericarditis, unstable angina, or intracranial aneurysm clipping procedure.

CONCLUSION

At the 5-year follow-up of SLE subjects with CP who were evaluated at baseline and follow-up, a majority had persistent CP, and nearly one-half had similar or worse myocardial perfusion consistent with CMD without obstructive CAD. These findings propose an alternative explanation for CP in SLE subjects compared to the more common SLE-related accelerated obstructive CAD accounting for CP and adverse outcomes. These findings support further studies of CMD as an etiology for cardiac morbidity and mortality in SLE.

Predicted Versus Observed Major Adverse Cardiac Event Risk in Women With Evidence of Ischemia and No Obstructive Coronary Artery Disease: A Report From WISE (Women's Ischemia Syndrome Evaluation)

Background Primary prevention risk scores are commonly used to predict cardiovascular (CVD) outcomes. The applicability of these scores in patients with evidence of myocardial ischemia but no obstructive coronary artery disease is unclear. Methods and Results Among 935 women with signs and symptoms of ischemia enrolled in WISE (Women's Ischemia Syndrome Evaluation), 567 had no obstructive coronary artery disease on angiography. Of these, 433 had had available risk data for 6 commonly used scores: Framingham Risk Score, Reynolds Risk Score, Adult Treatment Panel III, Atherosclerotic Cardiovascular Disease, Systematic Coronary Risk Evaluation, Cardiovascular Risk Score 2. Score-specific CVD rates were assessed. For each score, we evaluated predicted versus observed event rates at 10-year follow-up using c statistic. Recalibration was done for 3 of the 6 scores. The 433 women had a mean age of 56.9±9.4 years, 82.5% were white, 52.7% had hypertension, 43.6% had dyslipidemia, and 16.9% had diabetes mellitus. The observed 10-year score-specific CVD rates varied between 5.54% (Systematic Coronary Risk Evaluation) to 28.87% (Framingham Risk Score), whereas predicted event rates varied from 1.86% (Systematic Coronary Risk Evaluation) to 6.99% (Cardiovascular Risk Score 2). The majority of scores showed moderate discrimination (c statistic 0.53 for Atherosclerotic Cardiovascular Disease and Systematic Coronary Risk Evaluation; 0.78 for Framingham Risk Score) and underestimated risk (statistical discordance -58% for Adult Treatment Panel III; -84% for Atherosclerotic Cardiovascular Disease). Recalibrated Reynolds Risk Score, Atherosclerotic Cardiovascular Disease, and Framingham Risk Score had improved performance, but significant underestimation remained. Conclusions Commonly used CVD risk scores fail to accurately predict CVD rates in women with ischemia and no obstructive coronary artery disease. These results emphasize the need for new risk assessment scores to reliably assess this population.

Non-Obstructive Coronary Artery Disease in Women: Current Evidence and Future Directions

BACKGROUND

Over half of women who present with angina are found to have negative coronary angiographic assessments. Of these patients, up to 50% are diagnosed with coronary microvascular dysfunction (CMD), which refers to pathologic changes within the small vessels of the coronary circulation. The hallmark of the pathophysiology of CMD is that endothelial damage, which occurs due to a multitude of conditions and risk factors, is the inciting event for the development and progression of CMD. CMD leads to a mismatch in myocardial demand and perfusion, leading to signs and symptoms of cardiac ischemia in the absence of obstructive lesions in the major vessels. CMD can be diagnosed through a variety of both invasive methods that allow a more specific evaluation of the microvasculature and non-invasive imaging techniques, such as cardiac positron emission tomography (PET) and magnetic resonance imaging (MRI). Risk factors for CMD overlap significantly with those of obstructive coronary artery disease (CAD) - hypertension, hypercholesterolemia, and diabetes remain salient predictors. However, these conditions only account for 20% of CMD cases in females.

FINDINGS

Women have sex-specific risk factors such as menopause, pregnancy, polycystic ovarian syndrome (PCOS), and a higher proclivity toward chronic inflammatory disorders. Estrogen has a cardioprotective effect by increasing production of nitric oxide, a potent vasodilator released by endothelial cells. As a result, the hormonal changes of menopause may accelerate endothelial damage, and in turn, CMD. Current treatments focus on addressing the risk factors of cardiovascular disease, such as anti-hypertensive drugs, weight loss, and glucose control.

CONCLUSION

Given the multifactorial nature of CMD in women, and the extensive atypical risk factors for cardiac disease, a more nuanced approach is needed that addresses the varied pathophysiology of CMD.

Left ventricular concentric remodelling and functional impairment in women with ischaemia with no obstructive coronary artery disease and intermediate coronary flow reserve: a report from the WISE-CVD study

AIMS

Women with evidence of ischaemia but no obstructive coronary artery disease (INOCA) often have coronary microvascular dysfunction (CMD). Although invasively measured coronary flow reserve (CFR) is useful for the diagnosis of CMD, intermediate CFR values are often found of uncertain significance. We investigated myocardial flow reserve and left ventricular (LV) structural and functional remodelling in women with suspected INOCA and intermediate CFR.

METHODS AND RESULTS

Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD) study participants who had invasively measured intermediate CFR of 2.0≤ CFR ≤3.0 (n = 125) were included for this analysis. LV strain, peak filling rate (PFR) and myocardial perfusion reserve index (MPRI) were obtained by cardiac magnetic resonance imaging. Participants were divided: (i) Group 1 (n = 66) high MPRI ≥ 1.8, and (ii) Group 2 (n = 59) low MPRI < 1.8. The mean age was 54 ± 12 years and CFR was 2.46 ± 0.27. MPRI was significantly different but CFR did not differ between groups. LV relative wall thickness (RWT) trended higher in Group 2 and circumferential peak systolic strain and early diastolic strain rate were lower (P = 0.039 and P = 0.035, respectively), despite a similar LV ejection fraction and LV mass. PFR was higher in Group 1 and LV RWT was negatively related to PFR (r = -0.296, P = 0.001).

CONCLUSIONS

In women with suspected INOCA and intermediate CFR, those with lower MPRI had a trend towards more adverse remodelling and impaired diastolic LV function compared with those with higher MPRI. CFR was similar between the two groups. These findings provide evidence that both coronary microvessel vasomotion and structural and functional myocardial remodelling contribute to CMD.

"Myocardial transit-time" (MyoTT): a novel and easy-to-perform CMR parameter to assess microvascular disease

BACKGROUND

Myocardial microvascular disease may occur during the disease course of different cardiac as well as systemic disorders. With the present study, we introduce a novel and easy-to-perform cardiovascular magnetic resonance (CMR) parameter named "myocardial transit-time" (MyoTT).

METHODS

N = 20 patients with known hypertrophic cardiomyopathy (HCM) and N = 20 control patients without relevant cardiac disease underwent dedicated CMR studies on a 1.5-T MR scanner. The CMR protocol comprised cine and late-gadolinium-enhancement (LGE) imaging as well as first-pass perfusion acquisitions at rest for MyoTT measurement. MyoTT was defined as the blood circulation time from the orifice of the coronary arteries to the pooling in the coronary sinus (CS), and accordingly measured as the temporal difference between the appearances of CMR contrast agent in the aortic root and the CS reflecting the transit-time of gadolinium in the myocardial microvasculature.

RESULTS

Patients with HCM had a significantly prolonged MyoTT compared to controls (11.0 (9.1-14.5) s vs. 6.5 (4.8-8.4) s, p < 0.001). This significant difference did not change when the individual heart rate was taken into consideration (MyoTT indexed, p < 0.001). Significant correlations were found between MyoTT and maximal left ventricular (LV) wall thickness (r = 0.771, p < 0.001), MyoTT and presence of LGE (r = 0.760, p < 0.001) as well as MyoTT and LV global longitudinal strain (r = 0.672, p < 0.001). ROC analysis resulted in an area-under-curve (AUC) of 0.90 for MyoTT and showed an optimal sensitivity/specificity cut-off of 7.85 s to differentiate HCM from controls.

CONCLUSION

"Myocardial transit-time" is a novel and easy-to-perform CMR parameter that allows a quick assessment of the extent of myocardial microvascular disease. This novel CMR parameter may open new vistas in the assessment of microvascular disease-not only in HCM patients. Future studies will show the usefulness and clinical relevance of this novel CMR parameter.

Microcirculation function assessed by adenosine triphosphate stress myocardial contrast echocardiography and prognosis in patients with nonobstructive coronary artery disease

BACKGROUND

Recent studies have demonstrated that coronary microcirculation dysfunction (CMVD) is closely correlated with adverse clinical outcomes. In this study, quantitative stress myocardial contrast echocardiography (MCE) was used to evaluate the CMVD and to investigate its association with the prognosis of patients with nonobstructive coronary artery disease (CAD).

MATERIAL AND METHODS

From 2006 to 2014, 227 consecutive patients with chest pain and a diagnostic coronary angiography without significant coronary artery stenosis (<50%) who underwent adenosine triphosphate disodium (ATP) stress MCE were enrolled. Quantitative MCE measurements were analyzed using replenishment curves.

RESULTS

Median follow-up time of this study was 5.3 years. Predictors of impaired coronary flow reserve (CFR) were smoking, diabetes, high apolipoprotein B, high low-density lipoprotein, serum uric acid, and low apolipoprotein A. During follow-up, 22 patients were reported to have 30 cardiac events (21 unstable angina, 3 nonfatal myocardial infarctions, 6 percutaneous coronary interventions). Using multivariate analysis, abnormal β reserve (≤1.6), impaired CFR (≤2.0), and diabetes were independent predictors of primary endpoint events in patients with nonobstructive CAD (P < .05). Multivariate analysis showed that CFR ≤2.0 (odds ratio [OR] =  25.21, 95% confidence interval [CI]: 3.01-182.32; P = .003), β reserve ≤1.6 (OR = 29.96, 95% CI: 3.5-241.27; P = .002), and diabetic (OR = 33.11, 95% CI: 3.65-300.02; P = .002) significantly increased the risk of the primary endpoint events.

CONCLUSIONS

ATP stress quantitative MCE is a feasible and effective method to evaluate microcirculation abnormalities in human coronary arteries and it can be used for the clinical analysis, risk stratification, and treatment of early CAD.

Prevalence of Coronary Endothelial and Microvascular Dysfunction in Women with Symptoms of Ischemia and No Obstructive Coronary Artery Disease Is Confirmed by a New Cohort: The NHLBI-Sponsored Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD)

OBJECTIVE

In a separate, contemporary cohort, we sought to confirm findings of the original Women's Ischemia Syndrome Evaluation (WISE).

BACKGROUND

The original WISE observed a high prevalence of both invasively determined coronary endothelial and coronary microvascular dysfunction (CMD) that predicted adverse events in follow-up.

METHODS

We comparatively studied the WISE-Coronary Vascular Dysfunction (CVD) cohort (2009-2011), with signs and symptoms of ischemia but without significant CAD, to the original WISE (1997-2001) cohort. CMD was defined as coronary flow reserve (CFR) ≤2.5, or endothelial dysfunction as epicardial coronary artery constriction to acetylcholine (ACH), or <20% epicardial coronary dilation to nitroglycerin (NTG).

RESULTS

In WISE (n=181) and WISE-CVD (n=235) women, mean age in both was 54 years, and 83% were white (WISE) vs 74% (WISE-CVD, p=0.04). Use of hormone replacement therapy was less frequent in WISE-CVD vs WISE (46% vs 57%, p=0.026) as was presence of hypertension (40% vs 52%, p=0.013), hyperlipidemia (20% vs 46%, p<0.0001), and smoking (46% vs 56%, p=0.036). Similar rates were observed in WISE-CVD and WISE cohorts for CMD (mean CFR 2.7±0.6 vs 2.6±0.8, p=0.35), mean change in diameter with intracoronary ACH (0.2±10.0 vs 1.6±12.8 mm, p=0.34), and mean change in diameter with intracoronary NTG (9.7±13.0 vs 9.8±13.5 mm, p=0.94), respectively.

CONCLUSIONS

This study confirms prevalence of CMD in the contemporary WISE-CVD cohort similar to that of the original WISE cohort, despite a lower risk factor burden in WISE-CVD. Because these coronary functional abnormalities predict major adverse cardiac events, clinical trials of therapies targeting these abnormalities are indicated.

Maladaptive left ventricular remodeling in women: An analysis from the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction study

BACKGROUND

Women represent approximately half of heart failure hospitalizations and are disproportionately affected by heart failure with preserved ejection fraction (HFpEF). Women with signs and symptoms of ischemia, preserved left ventricular ejection fraction (LVEF), and no obstructive coronary artery disease (CAD) often have elevated left ventricular end-diastolic pressure (LVEDP). However, isolated elevated LVEDP in the absence of coronary microvascular dysfunction (CMD) is not understood.

METHODS

Among 244 women with signs and symptoms of ischemia, no obstructive CAD, and preserved LVEF who underwent invasive coronary reactivity testing (CRT), 43 (18%) women had no evidence of CMD. LVEDP was measured at time of CRT, and left ventricular (LV) volumes and mass were assessed by cardiac magnetic resonance (CMR) imaging.

RESULTS

Of the 43 women without CMD, 24 (56%) had elevated LVEDP [mean 18 mm Hg (SD = 3)] compared to 19 (44%) with normal LVEDP [11 mm Hg (SD = 3)]. The elevated LVEDP group had a comparatively higher systolic and diastolic blood pressure, lower LV end-diastolic volume index (EDVI), and higher mass-to-volume ratio. Other functional parameters were not significantly different.

CONCLUSIONS

Among women with signs and symptoms of ischemia without obstructive CAD, absence of CMD, and preserved LVEF, isolated elevated LVEDP is associated with a significantly higher systolic and diastolic blood pressure, higher LV mass-to-volume ratio and lower LV EDVI. These results suggest these women have maladaptive remodeling to blood pressure. Given the relatively high prevalence of HFpEF in women, these hypothesis-generating results suggest that further study of ventricular remodeling is warranted.

'Primary' Microvascular Angina: Clinical Characteristics, Pathogenesis and Management

Microvascular angina (MVA), i.e. angina caused by abnormalities of the coronary microcirculation, is increasingly recognised in clinical practice. The pathogenetic mechanisms of MVA are heterogeneous and may involve both structural and functional alterations of coronary microcirculation, and functional abnormalities may variably involve an impairment of coronary microvascular dilatation and an increased microvascular constrictor activity. Both invasive and non-invasive diagnostic tools exist to identify patients with MVA in clinical practice. Prognosis has been reported to be good in primary MVA patients, although the prognostic implications of coronary microvascular dysfunction (CMVD) in more heterogeneous populations of angina patients need further assessment. Management of primary MVA can be challenging, but pharmacological and non-pharmacological treatments exist that allow satisfactory control of symptoms in most patients.

A review of sex-specific benefits and risks of antithrombotic therapy in acute coronary syndrome

Over the past decade, more men than women have shown improved outcomes from antithrombotic therapies after acute coronary syndrome (ACS), which raises the question of whether there are sex-specific differences in treatment patterns and response to therapy. Differences in presenting clinical characteristics, pathophysiologic profile, and disparities in treatment may contribute to this outcomes discrepancy. Analyses of large trials and registry data suggest that male and female ACS patients experience similar benefits from antithrombotic therapy without significant difference in treatment utilization rates, yet women are consistently at higher risk of bleeding than men. Bleeding may result in antithrombotic treatment disruption, which increases the risk of long-term thrombotic events. Additionally, female ACS patients are more likely to receive suboptimal medication dosing and have lower rates of long-term medication adherence. These differences have significant clinical implications for women, indicating the need for strategies that will optimize initial treatment and long-term management attuned to these recognized sex-specific gaps.

Functional Approach for Coronary Artery Disease: Filling the Gap Between Evidence and Practice

The presence of myocardial ischemia is the most important prognostic factor in patients with coronary artery disease, and ischemia-directed revascularization has been a standard of care. Fractional flow reserve (FFR) is an invasive method used to detect the functionally significant epicardial coronary stenosis, and FFR-guided revascularization strategy has been proven to be superior to angiography-guided strategy. Recently, a hyperemia-free index, instantaneous wave free ratio (iFR), was developed and showed its non-inferiority for clinical outcomes compared with FFR-guided strategy. While evidence supporting the benefit of pressure wire assessment exists, there remain several unresolved issues, such as the mechanism of discordance between resting and hyperemic physiologic indices, clinical outcomes of patient/lesions with discordant results among the physiologic indices, role of physiologic indices beyond per-vessel decision tool, and the role of microvascular dysfunction in patient prognosis. The current article will review the recent studies performed to address these questions.

Sex-Related Differences in Vasomotor Function in Patients With Angina and Unobstructed Coronary Arteries

BACKGROUND

Coronary vasomotor dysfunction is an important mechanism for angina in patients with unobstructed coronary arteries.

OBJECTIVES

The purpose of this study was to determine sex differences in the prevalence and clinical presentation of vasomotor dysfunction in a European population and to examine sex differences in the dose of acetylcholine leading to a positive acetylcholine provocation test (ACH test).

METHODS

Between 2007 and 2014, we included 1,379 consecutive patients with stable angina, unobstructed coronaries and ACH test performed for epicardial vasospasm or coronary microvascular dysfunction (CMD) due to microvascular spasm. The predictive value of sex, risk factors, symptoms, and noninvasive test results was analyzed by means of logistic regression.

RESULTS

The mean patient age was 62 years, and 42% were male. There were 813 patients (59%) with a pathological ACH test, 33% for CMD and 26% for epicardial vasospasm. A pathological test was more common in females (70% vs. 43%; p < 0.001). In a multivariable logistic regression model the sex difference was statistically significant with a female-male odds ratio for CMD and epicardial vasospasm of 4.2 (95% confidence interval: 3.1 to 5.5; p < 0.001) and 2.3 (95% confidence interval: 1.7 to 3.1; p < 0.001), respectively. Effort-related symptoms, but neither risk factors nor noninvasive stress tests, contributed to predicting a pathological test. Female patients were more sensitive to acetylcholine with vasomotor dysfunction occurring at lower ACH doses compared with male patients.

CONCLUSIONS

Vasomotor dysfunction is frequent in patients with angina and unobstructed coronaries in a European population. Female patients have a higher prevalence of vasomotor dysfunction (especially CMD) compared with male patients. A pathological ACH test was observed at lower ACH doses in women compared with men.

International standardization of diagnostic criteria for microvascular angina

Standardization of diagnostic criteria for ischemic symptoms due to coronary microvascular dysfunction (CMD) is needed for further investigation of patients presenting with anginal chest pain consistent with "microvascular angina" (MVA). At the annual Coronary Vasomotion Disorders International Study Group (COVADIS) Summits held in August 2014 and 2015, the following criteria were agreed upon for the investigative diagnosis of microvascular angina: (1) presence of symptoms suggestive of myocardial ischemia; (2) objective documentation of myocardial ischemia, as assessed by currently available techniques; (3) absence of obstructive CAD (<50% coronary diameter reduction and/or fractional flow reserve (FFR) >0.80) (4) confirmation of a reduced coronary blood flow reserve and/or inducible microvascular spasm. These standardized criteria provide an investigative structure for mechanistic, diagnostic, prognostic and clinical trial studies aimed at developing an evidence base needed for guidelines in this growing patient population. Standardized criteria will facilitate microvascular angina registries and recruitment of suitable patients into clinical trials. Mechanistic research will also benefit from the implementation of standardized diagnostic criteria for MVA.

Determinants of coronary flow reserve in non-diabetic patients with chest pain without myocardial perfusion defects

Background

Microvascular dysfunction could be responsible for chest pain in patients without myocardial perfusion defects. We evaluated microvascular function using ultrasound-assessed coronary flow reserve (CFR) in patients with chest pain and normal myocardial perfusion scintigram. Secondly, we investigated association between cardiovascular parameters and decreased CFR in a sex specific manner.

Methods

A total of 202 (128 women) non-diabetic patients with chest pain and suspected myocardial ischemia, but without myocardial perfusion defects on myocardial perfusion scintigram, were enrolled and underwent CFR examination and blood sampling. All patients were followed-up for cardiovascular events. We used a supervised principal component analysis including 66 variables such as clinical parameters, ongoing medication, coronary artery disease history, lipids, metabolic parameters, inflammatory and other cardiovascular parameters.

Results

During a median follow-up time of 5.4 years, 25 cardiovascular events occurred; (men;18, women;7). Average CFR of the study cohort was 2.7±1.2 and 14% showed impaired CFR<2.0. In an adjusted Cox regression analysis, CFR<2.0 independently predicted event-free survival (HR:2.5, p = 0.033). In the supervised principal component analysis high insulin resistance assessed by Homeostatic model assessment for insulin resistance was the strongest biochemical marker associated with decreased CFR. Interestingly, upon sex specific multivariable linear regression analysis, the association was only significant in men (β = -0.132, p = 0.041) while systolic blood pressure remained an independent predictor in women (β = -0.009, p = 0.011).

Conclusions

In non-diabetic patients with chest pain without myocardial perfusion defects, low CFR has prognostic value for future cardiovascular events. Insulin resistance appears to be a marker for decreased CFR in men. Indeed, in the context of contribution of traditional risk factors in this patient population, the value of systolic blood pressure seems to be important in the women.

Ischemia and No Obstructive Coronary Artery Disease (INOCA): Developing Evidence-Based Therapies and Research Agenda for the Next Decade

The Cardiovascular Disease in Women Committee of the American College of Cardiology, in conjunction with interested parties (from the National Heart, Lung, and Blood Institute, American Heart Association, and European Society of Cardiology), convened a working group to develop a consensus on the syndrome of myocardial ischemia with no obstructive coronary arteries. In general, these patients have elevated risk for a cardiovascular event (including acute coronary syndrome, heart failure hospitalization, stroke, and repeat cardiovascular procedures) compared with reference subjects and appear to be at higher risk for development of heart failure with preserved ejection fraction. A subgroup of these patients also has coronary microvascular dysfunction and evidence of inflammation. This document provides a summary of findings and recommendations for the development of an integrated approach for identifying and managing patients with ischemia with no obstructive coronary arteries and outlines knowledge gaps in the area. Working group members critically reviewed available literature and current practices for risk assessment and state-of-the-science techniques in multiple areas, with a focus on next steps needed to develop evidence-based therapies. This report presents highlights of this working group review and a summary of suggested research directions to advance this field in the next decade.