Beyond Coronary Artery Disease: Assessing the Microcirculation.

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

Study on the Therapeutic Value of Shexiang Tongxin Dropping Pills in Patients with Stable Angina Pectoris of Coronary Heart Disease Complicated with Cognitive Impairment

Background: There is a pressing need to identify pharmaceuticals that are both safe and efficacious, with lower toxicity, for the treatment of stable angina pectoris in individuals suffering from coronary heart disease. The aim of this paper is to explore the therapeutic value of Shexiang Tongxin Dropping Pills in patients with stable angina pectoris of coronary heart disease complicated with cognitive impairment. Methods: 200 patients with stable angina pectoris combined with cognitive dysfunction and coronary heart disease admitted to our hospital from January 2022 to June 2023 were retrospectively selected as the study objects. According to the treatment method, the subjects were divided into a control group and a study group, with 100 cases in each group. The control group received conventional oral Western medicine, and the study group underwent treatment with Shexiang Tongxin Dropping Pills in addition to traditional Western medicine. The course of treatment was eight weeks. The enhancement in angina pectoris, cognitive function level, self-care ability, and clinical efficacy of both groups were assessed by comparing the conditions before and after the treatment. Results: After treatment, the frequency and duration of angina pectoris attacks in both groups were significantly lower than before, and the study group was lower than the control group (p < 0.05). The Montreal Cognitive Assessment (MoCA) score of both groups was higher than before, and the score of the study group was significantly higher than that of the control group (p < 0.05). Neuropsychiatric Inventory (NPI) scores in both groups were significantly lower than before, and the scores of the study group were significantly lower than those of the control group (p < 0.05). Traditional Chinese Medicine (TCM) syndrome scores in both groups were significantly lower than before, and the scores of the study group were significantly lower than those of the control group (p < 0.05). ... (AU)

Coronary Venous Pressure and Microvascular Hemodynamics in Patients With Microvascular Angina: A Randomized Clinical Trial.

Importance: The role of the coronary venous circulation in regulating myocardial perfusion and its potential in treating microvascular angina is unexplored. Objective: To evaluate whether an increase in coronary venous pressure modifies microvascular resistance in patients with microvascular angina. Design, Setting, and Participants: This was a blinded, sham-controlled, crossover, randomized clinical trial that enrolled participants between November 2021 and January 2023. Participants for this physiology end point study were recruited from the Cardiology Center of the University of Medicine in Mainz, Germany. Patients with moderate/severe angina pectoris (Canadian Cardiovascular Society class 2-4) due to microvascular dysfunction (as defined by the thermodilution-based index of microvascular resistance >25 mm Hg × s). Exclusion criteria were epicardial coronary disease, second- and third-degree atrioventricular block, severe valvular heart disease, cardiomyopathy, and pulmonary or kidney disease. Intervention: Inflation of an undersized balloon placed in the cardiac coronary sinus (CS), hereafter referred to as balloon and the deflated balloon in the right atrium, referred to as sham. Measurements were performed at rest and during maximal coronary hyperemia. Both patients and final assessors were blinded to the randomization sequence. Main Outcomes and Measures: Hemodynamic parameters, including aortic (Pa) and distal (Pd) coronary pressure, coronary sinus pressure (Pcs), right atrial pressure (Pra), and the mean transit time (inverse of blood flow [Tmn]), were measured. Results: A total of 20 patients (median [IQR] age, 69 [64-75] years; 11 female [55.0%]) were included in the study. Two patients (10%) had diabetes, 6 (30%) had hypercholesterolemia, 15 (75%) had hypertension, and 3 (15%) were active smokers. The inflation of the CS balloon caused a significant increase in CS pressure at rest and during hyperemia (300% and 317% increase, respectively, compared with sham, both P < .001), a decrease in hyperemic distal coronary pressure (median [IQR], sham: 92 [80-100] mm Hg; balloon: 79 [75-93] mm Hg; P = .01) and mean transit time (sham: 0.39 [0.23-0.62] s; balloon: 0.26 [0.17-0.46] s; P = .008). As a result, CS occlusion led to a decrease in both resting coronary resistance (median [IQR], sham: 59 [37-87] mm Hg × s; balloon: 42 [31-67] mm Hg × s; P = .005) and the primary end point hyperemic coronary resistance (mean [IQR], sham: 31 [23-53] mm Hg × s; balloon: 14 [8-26] mm Hg × s; P < .001). Conclusion and Relevance: Increased coronary venous pressure led to a reduction of microvascular resistances in patients with microvascular angina, a mechanism with potential implications for the therapy of this complex disease. Trial Registration: ClinicalTrials.gov Identifier: NCT05034224.

Effects of remote ischemic preconditioning on coronary blood flow and microcirculation.

This study aimed to determine the effect of short-term remote ischemic preconditioning (RIPC) on coronary blood flow and microcirculation function using the quantitative flow ratio (QFR) and index of microcirculatory resistance (IMR). We randomly divided 129 patients undergoing coronary angiography (CAG) into RIPC and control groups. Following the first CAG, we randomly divided the patients further into the unilateral upper limb and lower limb groups for four cycles of ischemia/reperfusion circulation; subsequently, we performed the second CAG. During each CAG, contrast-flow QFR (cQFR), fixed-flow QFR (fQFR), and IMR (in patients with cardiac syndrome X) were calculated and compared. We measured 253 coronary arteries in 129 patients. Compared to the control group, the average cQFR of the RIPC group increased significantly after RIPC. Additionally, 23 patients with cardiac syndrome X (IMR > 30) were included in this study. Compared to the control group, IMR and the difference between cQFR and fQFR (cQFR-fQFR) both decreased significantly after receiving RIPC. The application of RIPC can increase coronary blood flow and improve coronary microcirculation function.

Microvascular arterial disease of the brain and the heart: a shared pathogenesis.

Microvascular arterial disease in the heart manifest as coronary microvascular dysfunction. This condition causes microvascular angina and is associated increased morbidity and mortality. Microvascular arterial disease in the brain is referred to as cerebrovascular small vessel disease. This is responsible for 45% of dementias and 25% of ischaemic strokes. The heart and brain share similar vascular anatomy and common pathogenic risk factors are associated with the development of both coronary microvascular dysfunction and cerebrovascular small vessel disease. Microvascular disease in the heart and brain also appear to share common multisystem pathophysiological mechanisms. Further studies on diagnostic approaches, epidemiology and development of disease-modifying therapy seem warranted.

[Angina Pectoris and the Importance of Coronary Microcirculation in Practice]. / Angina pectoris und die Bedeutung der koronaren Mikrozirkulation in der Praxis.

Angina Pectoris and the Importance of Coronary Microcirculation in Practice Abstract. Microvascular angina is a common manifestation of coronary microvascular dysfunction, particulary prevalent in post-menopausal women above the age of 50 and associated with impaired quality of life and poor clinical outcomes. However, microvascular angina remains largely undetected given the underuse of diagnostic tools for the assessment of coronary microvascular function. As a consequence, many of these patients suffering from coronary microvascular dysfunction fail to receive the appropriate medical treatment and remain in the long term symptomatic. Invasive coronary catheterization with measurement of coronary flow reserve and intracoronary acetylcholine provocation testing allows for the assessment of coronary microvascular dysfunction, and a therapy targeting specific physiological pathways can be implemented. A targeted therapy includes lifestyle modifications, secondary prevention measures, and anti-anginal medication. Ongoing clinical research in the field is expected to deliver novel diagnostic and therapeutic concepts for an improved management of patients with coronary microvascular disease.

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

PURPOSE: Physical activity is recommended for patients with coronary microvascular dysfunction, however, avoided due to fear about the heart. The aim is to achieve an understanding of the meaning of physical activity one year after participating in a high-intensity exercise training program. METHOD: Twelve people were interviewed using a phenomenological hermeneutic approach. RESULTS: Four themes were formulated and revealed that one year after participating in high-intensity exercise training participants had an awareness of the meaning of the project, their chest pain and daily life: Being reassured, Daily life's impact on chest pain and continuing doing high-intensity exercise training, A strengthened body and mind, Being part of a group of people with similar problems.Comprehensive understanding was formulated as "Being reassured according being physically active in a background of vulnerability". CONCLUSION: This study indicates that by going through the high-intensity exercise training program the person regains more unity with the lived body and an unfolding life. A person-centred approach is suggested including an underlying dimension of vulnerability. A lifeworld led care means meeting the patient in their way of relating to the world bodily and existentially. Taking this understanding into consideration will advance the requirements for establishing person-centred care.

Beyond Coronary Artery Disease: Assessing the Microcirculation.

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

Phenotype-based management of coronary microvascular dysfunction.

40-70% of patients undergoing invasive coronary angiography with signs and symptoms of ischemia are found to have no obstructive coronary artery disease (INOCA). When this heterogeneous group undergo coronary function testing, approximately two-thirds have demonstrable coronary microvascular dysfunction (CMD), which is independently associated with adverse prognosis. There are four distinct phenotypes, or subgroups, each with unique pathophysiological mechanisms and responses to therapies. The clinical phenotypes are microvascular angina, vasospastic angina, mixed (microvascular and vasospastic), and non-cardiac symptoms (reclassification as non-INOCA). The Coronary Vasomotor Disorders International Study Group (COVADIS) have proposed standardized criteria for diagnosis. There is growing awareness of these conditions among clinicians and within guidelines. Testing for CMD can be done using invasive or non-invasive modalities. The CorMicA study advocates the concept of 'functional angiography' to guide stratified medical therapy. Therapies broadly fall into two categories: those that modulate cardiovascular risk and those to alleviate angina. Management should be tailored to the individual, with periodic reassessment for efficacy. Phenotype-based management is a worthy endeavor for both patients and clinicians, aligning with the concept of 'precision medicine' to improve prognosis, symptom burden, and quality of life. Here, we present a contemporary approach to the phenotype-based management of patients with INOCA.

[Coronary microvascular dysfunction: mechanisms and clinical outcome]. / La patologia microvascolare coronarica: meccanismi e contesti clinici.

A large percentage of patients, predominantly female, who undergo coronary angiography for typical chest pain do not have significant coronary stenosis. Many of these patients with microvascular myocardial disease have left ventricular hypertrophy, cardiomyopathies, valve disease, or other clinical conditions. The definition of microvascular angina is based on (i) symptoms of myocardial ischemia, (ii) absence of obstructive coronary artery disease (<50% stenosis on coronary angiography or coronary computed tomography scan), (iii) objective evidence of myocardial ischemia (ischemic electrocardiographic abnormalities during episodes of chest pain and/or myocardial perfusion defects or regional contractility abnormalities), and (iv) pathological indices of microcirculation (index of microcirculatory resistance >25, coronary flow reserve <2.0) and/or microvascular spasm (TIMI flow <2) during intracoronary vasoreactivity tests. The basic mechanisms and the diagnostic tests of microvascular dysfunction are reported in detail.From a clinical standpoint, while the crucial role of microcirculation in determining short- and long-term prognosis is evident, efforts to date to improve clinical outcomes in patients with microvascular obstruction have had limited success, most likely because microvascular dysfunction is a multifactorial process with several interdependent underlying pathophysiological mechanisms. Therefore, further studies are needed to develop effective therapeutic strategies for microvascular myocardial disease.

Definition and epidemiology of coronary microvascular disease.

Ischemic heart disease remains one of the leading causes of death and disability worldwide. However, most patients referred for a noninvasive computed tomography coronary angiogram (CTA) or invasive coronary angiogram for the investigation of angina do not have obstructive coronary artery disease (CAD). Approximately two in five referred patients have coronary microvascular disease (CMD) as a primary diagnosis and, in addition, CMD also associates with CAD and myocardial disease (dual pathology). CMD underpins excess morbidity, impaired quality of life, significant health resource utilization, and adverse cardiovascular events. However, CMD often passes undiagnosed and the onward management of these patients is uncertain and heterogeneous. International standardized diagnostic criteria allow for the accurate diagnosis of CMD, ensuring an often overlooked patient population can be diagnosed and stratified for targeted medical therapy. Key to this is assessing coronary microvascular function-including coronary flow reserve, coronary microvascular resistance, and coronary microvascular spasm. This can be done by invasive methods (intracoronary temperature-pressure wire, intracoronary Doppler flow-pressure wire, intracoronary provocation testing) and non-invasive methods [positron emission tomography (PET), cardiac magnetic resonance imaging (CMR), transthoracic Doppler echocardiography (TTDE), cardiac computed tomography (CT)]. Coronary CTA is insensitive for CMD. Functional coronary angiography represents the combination of CAD imaging and invasive diagnostic procedures.

Interventional Diagnostic Procedure: a Practical Guide for the Assessment of Coronary Vascular Function.

Approximately 40% of patients undergoing invasive coronary angiography for investigation of angina are found to have no obstructive coronary artery disease (ANOCA). Abnormal coronary function underlies coronary vasomotion syndromes including coronary endothelial dysfunction, microvascular angina, vasospastic angina, post-PCI angina and myocardial infarction with no obstructive coronary arteries (MINOCA). Each of these endotypes are distinct subgroups, characterized by specific disease mechanisms. Diagnostic criteria and linked therapy for these conditions are now established by expert consensus and clinical guidelines. Coronary function tests are performed as an adjunctive interventional diagnostic procedure (IDP) in appropriately selected patients during coronary angiography. This aids differentiation of patients according to endotype. The IDP includes two distinct components: a diagnostic guidewire test and a pharmacological coronary reactivity test. The tests last approximately 5 minutes for the former and 10-15 minutes for the latter. Patient safety and staff education are key. The diagnostic guidewire test measures parameters of coronary flow limitation (fractional flow reserve [FFR], coronary flow reserve [CFR], microvascular resistance [index of microvascular resistance (IMR)], basal resistance index, and vasodilator function [CFR, resistive reserve ratio (RRR)]). The pharmacological coronary reactivity test measures the vasodilator potential and propensity to vasospasm of both the main coronary arteries and the micro-vessels. It involves intra-coronary infusion of acetylcholine and glyceryl trinitrate (GTN). Acetylcholine is not licensed for parenteral use and is therefore prescribed on a named-patient basis. Vasodilatation is the normal, expected response to infusion of physiological concentrations of acetylcholine. Vascular spasm represents an abnormal response, which supports the diagnosis of vasospastic angina. The purpose of this practical guide is to provide information on the preparation and administration of the IDP in clinical practice. It discusses some key preparation and safety considerations, as well as tips for procedural success. The IDP supports stratified medicine for a personalized approach to health and wellbeing.

Microvascular angina (Cardiac Syndrome X) from a historical overview, epidemiology, pathophysiology to treatment recommendations - a minireview.

Microvascular angina (MVA) is a condition characterized by the presence of angina-like chest pain, a positive response to exercise stress tests, and no significant stenosis of coronary arteries in coronary angiography, with absence of any other specific cardiac diseases. The etiology of this syndrome is still not known and it is probably multifactorial. Coronary microvascular dysfunction is proposed as the main pathophysiological mechanism in the development of MVA. Altered somatic and visceral pain perception and autonomic imbalance, in addition to myocardial ischemia, has been observed in subjects with MVA, involving dynamic variations in the vasomotor tone of coronary microcirculation with consequent transient ischemic episodes. Other theories suggest that MVA may be a result of a chronic inflammatory state in the body that can negatively influence the endothelium or a local imbalance of factors regulating its function. This article presents the latest information about the epidemiology, diagnostics, etiopathogenesis, prognosis, and treatment of patients with MVA.

Cardiac syndrome X - the present knowledge. / Kardiologiczny zespól X ­ aktualny stan wiedzy.

The aim of this work was to define the notion of cardiac syndrome X based on latest research, determine its connection with mental disturbances and present the current therapeutic directions. Cardiac syndrome X was distinguished in 1973 to describe a group of patients with coronary syndrome symptoms despite normalcoronary vessels in coronarography. Many years have passed since then, but the syndrome definition and the diagnostic criteria still arouse controversy. It is estimated that 10 to 20% of persons who undergo coronarography suffer from cardiac syndrome X, a vast majority of them being perimenopausal women. That patient population suffers from anxiety disorders, depressive symptoms and sleep disturbances much more frequently than does general population. Treatment includes a range of medicines with various mechanisms of action, but their effectiveness is limited; non-pharmacological actions are a significant part of the therapy. The patient group with cardiac syndrome X requires periodic follow-ups because prospective observation has shown that it is a risk group concerning development of atherosclerosis and acute coronary syndrome.

Comprehensive treatment of microvascular angina in overweight women - a randomized controlled pilot trial.

AIMS: Coronary microvascular dysfunction (CMD) carries a poor cardiovascular prognosis and may explain angina in women without obstructive coronary artery disease (CAD). Currently, no evidence-based treatment for CMD exists. We investigated whether reducing cardiovascular risk factors improves symptoms and microvascular function in women with non-endothelial dependent CMD and no obstructive CAD. METHODS: We randomized 62 women aged 40-75, with body mass index (BMI) >25 kg/m2, angina ≥monthly, and coronary flow velocity reserve (CFVR) ≤2.5 to a 24-week intervention comprising low energy diet, exercise training, and optimized treatment of hypertension, dyslipidemia and diabetes or to control. Patients were assessed before randomization and after 24 weeks. Primary outcomes were CFVR assessed by transthoracic Doppler stress-echocardiography and angina burden by Seattle Angina Questionnaire (SAQ). Secondary outcomes were exercise capacity, body composition, glycemic control, myocardial function, and anxiety and depression symptoms. RESULTS: Fifty-six participants (90%) completed the study. Median (IQR) age was 65.2 (57.1;70.7) years, BMI was 30.1 (28.4;32.7) kg/m2. The intervention resulted in relevant improvement in angina symptoms (9-21-point increase on SAQ-scales (all p<0.01)) but had no effect on CFVR (p = 0.468). Mean (CI) weight loss was 9.6 (7.80;11.48) kg, (p<0.0001). There was a significant mean (CI) decrease in depression symptoms = 1.16 (0.22;2.12), triglycerides = 0.52 (0.25;0.78) mmol/L, total cholesterol = 0.55 (0.12;0.98) mmol/L, and HbA1c in diabetics = 27.1 (1.60;52.6) mmol/mol but no effect on other secondary outcomes. CONCLUSION: A major weight loss and intensified risk factor control resulted in significantly improved angina burden but no improvement of coronary microvascular function among women with microvascular angina.

Rationale and design of the British Heart Foundation (BHF) Coronary Microvascular Function and CT Coronary Angiogram (CorCTCA) study.

Microvascular and/or vasospastic anginas are relevant causes of ischemia with no obstructive coronary artery disease (INOCA) in patients after computed tomography coronary angiography (CTCA). OBJECTIVES: Our research has 2 objectives. The first is to undertake a diagnostic study, and the second is to undertake a nested, clinical trial of stratified medicine. DESIGN: A prospective, multicenter, randomized, blinded, sham-controlled trial of stratified medicine (NCT03477890) will be performed. All-comers referred for clinically indicated CTCA for investigation of suspected coronary artery disease (CAD) will be screened in 3 regional centers. Following informed consent, eligible patients with angina symptoms are enrolled before CTCA and remain eligible if CTCA excludes obstructive CAD. Diagnostic study: Invasive coronary angiography involving an interventional diagnostic procedure (IDP) to assess for disease endotypes: (1) angina due to obstructive CAD (fractional flow reserve ≤0.80); (2) microvascular angina (coronary flow reserve <2.0 and/or index of microvascular resistance >25); (3) microvascular angina due to small vessel spasm (acetylcholine); (4) vasospastic angina due to epicardial coronary spasm (acetylcholine); and (5) noncoronary etiology (normal coronary function). The IDP involves direct invasive measurements using a diagnostic coronary guidewire followed by provocation testing with intracoronary acetylcholine. The primary outcome of the diagnostic study is the reclassification of the initial CTCA diagnosis based on the IDP. Stratified medicine trial: Participants are immediately randomized 1:1 in the catheter laboratory to therapy stratified by endotype (intervention group) or not (control group). The primary outcome of the trial is the mean within-subject change in Seattle Angina Questionnaire score at 6 months. Secondary outcomes include safety, feasibility, diagnostic utility (impact on diagnosis and certainty), and clinical utility (impact on treatment and investigations). Health status assessments include quality of life, illness perception, anxiety-depression score, treatment satisfaction, and physical activity. Participants who are not randomized will enter a follow-up registry. Health and economic outcomes in the longer term will be assessed using electronic patient record linkage. VALUE: CorCTCA will prospectively characterize the prevalence of disease endotypes in INOCA and determine the clinical value of stratified medicine in this population.

Effects of a Cardiac Rehabilitation Program Versus Usual Care on Cardiopulmonary Function in Patients With Cardiac Syndrome X.

PURPOSE: Because of uncertainty in the pathophysiological process, the treatment of cardiac syndrome X (CSX) is still under study. Addressing the effects of cardiac rehabilitation (CR) can help promote the prescription of this modality as an adjuvant therapy for these patients. METHODS: This study was performed on 30 patients with effort-induced angina pectoris using a positive exercise test and/or myocardial perfusion scan in the absence of obvious stenosis or a stenosis of <50% on coronary angiography. The patients were divided into the CR and usual care (UC) groups and underwent cardiopulmonary exercise testing with gas exchange analysis before and after the study. The Duke Treadmill Score was used to compare prognosis and survival estimates of patients. RESULTS: An increase in peak oxygen uptake ((Equation is included in full-text article.)O2) was significantly higher in the CR group than in the control group (P = .017). Resting (Equation is included in full-text article.)O2 was also increased in the CR group, but its difference with the UC group was not statistically significant. Resting O2 pulse was increased in the CR group, which significantly differed between groups (P = .041). Exercise test duration and the Duke Treadmill Score significantly increased in the CR group as compared with the UC group (P = .003 and P = .002, respectively). Also, recovery heart rate in the first minute was significantly improved in CR group. CONCLUSION: Adding a 4-wk course of CR to UC for patients with CSX not only increased the Duke Treadmill Score and exercise test duration but also improved the resting O2 pulse, peak (Equation is included in full-text article.)O2, and first-minute recovery heart rate.

Reappraisal of Ischemic Heart Disease.

In recent years, it has become apparent that coronary microvascular dysfunction plays a pivotal pathogenic role in angina pectoris. Functional and structural mechanisms can affect the physiological function of the coronary microvasculature and lead to myocardial ischemia in people without coronary atheromatous disease and also in individuals with obstructive coronary artery disease. Abnormal dilatory responses of the coronary microvessels, coronary microvascular spasm, and extravascular compressive forces have been identified as pathogenic mechanisms in both chronic and acute forms of ischemic heart disease. The condition characterized by anginal symptoms and evidence of myocardial ischemia triggered by coronary microvascular dysfunction, in the absence of obstructive coronary disease, is known as microvascular angina. The concept of microvascular angina, however, may extend further to include patients with obstructive coronary artery disease and individuals with angina after coronary revascularization or heart transplantation because coronary microvascular dysfunction contributes to myocardial ischemia in many such patients. Patients with microvascular angina constitute a sizeable proportion of all cases of stable angina undergoing diagnostic coronary angiography and of those with persisting angina after successful coronary revascularization. Coronary microvascular dysfunction is also often responsible for angina in individuals with cardiomyopathy and heart valve disease as well as acute coronary syndrome cases such as Takotsubo syndrome and myocardial infarction with no obstructive coronary artery disease. Patients with stable microvascular angina present typically with effort or rest chest pain and a reduced coronary flow reserve or microvascular spasm. This condition, which affects women and men, can markedly impair quality of life and prognosis and represents a substantial cost burden to healthcare systems and individuals alike. In recent years, progress in the diagnosis of myocardial ischemia and the use of tests to investigate functional and structural causes for a reduced coronary flow reserve and microvascular spasm have allowed the identification of an increased number of cases of microvascular angina in everyday clinical practice. Although some of the available anti-anginal drugs may be helpful, treatment of coronary microvascular dysfunction remains a major challenge. The present article discusses the fundamental role that coronary microvascular dysfunction plays in the pathogenesis of ischemic heart disease, the clinical characteristics of patients presenting with microvascular angina, and possible diagnostic and therapeutic strategies.