Physical training in Syndrome X: physical training counteracts deconditioning and pain in Syndrome X

Metabolic Characteristics of Gut Microbiota and Insomnia: Evidence from a Mendelian Randomization Analysis

Insomnia is a common sleep disorder that significantly impacts individuals' sleep quality and daily life. Recent studies have suggested that gut microbiota may influence sleep through various metabolic pathways. This study aims to explore the causal relationships between the abundance of gut microbiota metabolic pathways and insomnia using Mendelian randomization (MR) analysis. This two-sample MR study used genetic data from the OpenGWAS database (205 gut bacterial pathway abundance) and the FinnGen database (insomnia-related data). We identified single nucleotide polymorphisms (SNPs) associated with gut bacterial pathway abundance as instrumental variables (IVs) and ensured their validity through stringent selection criteria and quality control measures. The primary analysis employed the inverse variance-weighted (IVW) method, supplemented by other MR methods, to estimate causal effects. The MR analysis revealed significant positive causal effects of specific carbohydrate, amino acid, and nucleotide metabolism pathways on insomnia. Key pathways, such as gluconeogenesis pathway (GLUCONEO.PWY) and TCA cycle VII acetate producers (PWY.7254), showed positive associations with insomnia (B > 0, p < 0.05). Conversely, pathways like hexitol fermentation to lactate, formate, ethanol and acetate pathway (P461.PWY) exhibited negative causal effects (B < 0, p < 0.05). Multivariable MR analysis confirmed the independent causal effects of these pathways (p < 0.05). Sensitivity analyses indicated no significant pleiotropy or heterogeneity, ensuring the robustness of the results. This study identifies specific gut microbiota metabolic pathways that play critical roles in the development of insomnia. These findings provide new insights into the biological mechanisms underlying insomnia and suggest potential targets for therapeutic interventions. Future research should further validate these causal relationships and explore how modulating gut microbiota or its metabolic products can effectively improve insomnia symptoms, leading to more personalized and precise treatment strategies.

Coronary Microvascular Dysfunction: A Guide for Clinicians

Dysfunction of the coronary microvasculature has become increasingly recognized as an important mechanism of myocardial ischemia in patients without obstructive coronary artery disease. The causes and management of coronary microvascular dysfunction remain poorly understood and are still largely based on extrapolation of epicardial coronary artery disease data. Quantification of myocardial blood flow and flow reserve have improved diagnosis, though important questions remain. In this review, we explain current understanding of the spectrum of pathophysiology of coronary microvascular dysfunction, summarize current diagnostic techniques to assess for coronary microvascular dysfunction, and appraise the limited data on management options specifically for patients with coronary microvascular dysfunction.

Intrinsic and Extrinsic Contributors to the Cardiac Benefits of Exercise

Among its many cardiovascular benefits, exercise training improves heart function and protects the heart against age-related decline, pathological stress, and injury. Here, we focus on cardiac benefits with an emphasis on more recent updates to our understanding. While the cardiomyocyte continues to play a central role as both a target and effector of exercise's benefits, there is a growing recognition of the important roles of other, noncardiomyocyte lineages and pathways, including some that lie outside the heart itself. We review what is known about mediators of exercise's benefits-both those intrinsic to the heart (at the level of cardiomyocytes, fibroblasts, or vascular cells) and those that are systemic (including metabolism, inflammation, the microbiome, and aging)-highlighting what is known about the molecular mechanisms responsible.

Comprehensive Management of ANOCA, Part 2-Program Development, Treatment, and Research Initiatives: JACC State-of-the-Art Review

Centers specializing in coronary function testing are critical to ensure a systematic approach to the diagnosis and treatment of angina with nonobstructive coronary arteries (ANOCA). Management leveraging lifestyle, pharmacology, and device-based therapeutic options for ANOCA can improve angina burden and quality of life in affected patients. Multidisciplinary care teams that can tailor and titrate therapies based on individual patient needs are critical to the success of comprehensive programs. As coronary function testing for ANOCA is more widely adopted, collaborative research initiatives will be fundamental to improve ANOCA care. These efforts will require standardized symptom assessments and data collection, which will propel future large-scale clinical trials.

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

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

[Angina Pectoris and the Importance of Coronary Microcirculation in Practice]

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.

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

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

The Central Nervous System and Psychosocial Factors in Primary Microvascular Angina

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

Microvascular Angina: Diagnosis and Management

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

Management of ischaemia with non-obstructive coronary arteries (INOCA)

Up to half of patients undergoing elective coronary angiography for the investigation of chest pain do not present with evidence of obstructive coronary artery disease. These patients are often discharged with a diagnosis of non-cardiac chest pain, yet many could have an ischaemic basis for their symptoms. This type of ischaemic chest pain in the absence of obstructive coronary artery disease is referred to as INOCA (ischaemia with non-obstructive coronary arteries). This comprehensive review of INOCA management looks at why these patients require treatment, who requires treatment based on diagnostic evaluation, what clinical treatment targets should be considered, how to treat patients using a personalised medicine approach, when to initiate treatment, and where future research is progressing.

ESC Working Group on Coronary Pathophysiology and Microcirculation position paper on 'coronary microvascular dysfunction in cardiovascular disease'

Although myocardial ischaemia usually manifests as a consequence of atherosclerosis-dependent obstructive epicardial coronary artery disease, a significant percentage of patients suffer ischaemic events in the absence of epicardial coronary artery obstruction. Experimental and clinical evidence highlight the abnormalities of the coronary microcirculation as a main cause of myocardial ischaemia in patients with 'normal or near normal' coronary arteries on angiography. Coronary microvascular disturbances have been associated with early stages of atherosclerosis even prior to any angiographic evidence of epicardial coronary stenosis, as well as to other cardiac pathologies such as myocardial hypertrophy and heart failure. The main objectives of the manuscript are (i) to provide updated evidence in our current understanding of the pathophysiological consequences of microvascular dysfunction in the heart; (ii) to report on the current knowledge on the relevance of cardiovascular risk factors and comorbid conditions for microcirculatory dysfunction; and (iii) to evidence the relevance of the clinical consequences of microvascular dysfunction. Highlighting the clinical importance of coronary microvascular dysfunction will open the field for research and the development of novel strategies for intervention will encourage early detection of subclinical disease and will help in the stratification of cardiovascular risk in agreement with the new concept of precision medicine.

Treatment of coronary microvascular dysfunction

Contemporary data indicate that patients with signs and symptoms of ischaemia and non-obstructive coronary artery disease (INOCA) often have coronary microvascular dysfunction (CMD) with elevated risk for adverse outcomes. Coronary endothelial (constriction with acetylcholine) and/or microvascular (limited coronary flow reserve with adenosine) dysfunction are well-documented, and extensive non-obstructive atherosclerosis is often present. Despite these data, patients with INOCA currently remain under-treated, in part, because existing management guidelines do not address this large, mostly female population due to the absence of evidence-based data. Relatively small sample-sized, short-term pilot studies of symptomatic mostly women, with INOCA, using intense medical therapies targeting endothelial, microvascular, and/or atherosclerosis mechanisms suggest symptom, ischaemia, and coronary vascular functional improvement, however, randomized, controlled outcome trials testing treatment strategies have not been completed. We review evidence regarding CMD pharmacotherapy. Potent statins in combination with angiotensin-converting enzyme inhibitor (ACE-I) or receptor blockers if intolerant, at maximally tolerated doses appear to improve angina, stress testing, myocardial perfusion, coronary endothelial function, and microvascular function. The Coronary Microvascular Angina trial supports invasive diagnostic testing with stratified therapy as an approach to improve symptoms and quality of life. The WARRIOR trial is testing intense medical therapy of high-intensity statin, maximally tolerated ACE-I plus aspirin on longer-term outcomes to provide evidence for guidelines. Novel treatments and those under development appear promising as the basis for future trial planning.

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.

Women with coronary microvascular dysfunction and no obstructive coronary artery disease have reduced exercise capacity

BACKGROUND

Both coronary microvascular dysfunction (CMD) and reduced exercise capacity are associated with adverse cardiovascular prognosis. The association between CMD and cardiopulmonary exercise testing (CPET) derived exercise capacity in symptomatic individuals without obstructive coronary artery disease (CAD) is not clear. We investigated whether exercise capacity was reduced in women with angina, CMD and no obstructive CAD compared with sex-matched controls. Furthermore, we assessed the association between CMD and other CPET-derived variables.

METHODS

All participants underwent transthoracic Doppler echocardiography of the left anterior descending artery with dipyridamole-induced vasodilation and CPET using ergometer cycle with an incremental test protocol.

RESULTS

We included 99 women with angina and no obstructive CAD (patients) and 27 asymptomatic women (controls), age (mean ± standard deviation) 61 ± 10 and 58 ± 10 years, respectively. Patients had a higher burden of risk factors compared with controls, while the weekly physical activity level was comparable between the groups (p = 0.72). CMD was present in 27 (27%) patients and 5 (19%) controls. Peak VO₂ was significantly reduced in patients with CMD compared with controls with normal coronary microvascular function ((median (IQR) 17.3 (15.5-21.3) vs. 27.3 (21.6-30.8) ml/kg/min; age-adjusted p = 0.001), independent of cardiovascular risk factors (p = 0.041). Presence of CMD in symptomatic women was also associated with diminished heart rate reserve (p < 0.001) and blunted heart rate recovery.

CONCLUSIONS

Women with angina, CMD and no obstructive CAD have markedly reduced exercise capacity compared with sex-matched controls. Moreover, combination of angina and CMD is associated with impaired heart rate response and heart rate recovery.

Recognition and treatment of ischemic heart diseases in women

Heart disease is the leading cause of death among women in the industrialized world. However, women after myocardial infarctions (MIs) are less likely to receive preventive medications or revascularization and as many as 47% experience heart failure, stroke or die within 5 years. Premenopausal women with MIs frequently have coronary plaque erosions or dissections. Women under 50 years with angina and nonobstructive epicardial coronary artery disease often have coronary microvascular dysfunction (CMD) with reductions in coronary flow reserve that may require nontraditional therapies. In women with coronary artery disease treated with stents, the 3-year incidence of recurrent MI or death is 9.2%. Coronary bypass surgery operative mortality averages 4.6% for women compared with 2.4% in men. Addition of internal mammary artery and radial artery coronary grafts in women does not increase operative survival but improves 5-year outcome to greater than 80%.

Cardiac Rehabilitation and Exercise Prescription in Symptomatic Patients with Non-Obstructive Coronary Artery Disease-a Systematic Review

Purpose of review

Non-obstructive coronary artery disease (NOCAD) on coronary angiography is a common finding in patients with stable angina. Angina in NOCAD patients is thought to be caused by endothelial dysfunction of the epicardial coronary arteries and/or the microvasculature. Treatment is empiric, and 30% of patients remain symptomatic in spite of therapy. It is well known that physical exercise can improve endothelial function. The goal of this review was to assess the current literature on effects of physical exercise in NOCAD patients with angina. Therefore, a literature search was conducted to March 13, 2018 using the following search terms: syndrome X, microvascular angina, non-obstructive coronary artery disease and exercise training, cardiac rehabilitation, endothelial function. All original publications were included which examined the effect of a cardiac rehabilitation (CR) program or exercise training (ET) on patients with angina and NOCAD.

Recent findings

Eight studies, of which four were randomized controlled studies, examined 218 participants, 162 in an intervention and 56 in control groups. Most patients were women (97.7%). Exercise programs varied from 8 weeks to 4 months at moderate intensity and some included relaxation therapy. The studies examined the effect of CR on exercise capacity, quality of life (QoL), and perfusion defects. CR increased exercise capacity, oxygen uptake, symptom severity, and QoL. Myocardial perfusion improved.

Summary

CR appears to be beneficial in symptomatic patients with NOCAD, improving exercise capacity and QoL and reducing severity of symptoms and myocardial perfusion defects. Data is limited to a small number of predominantly female patients. Further larger trials are warranted to determine the optimal rehabilitation protocols and define its long-term benefits.

Coronary Slow-Flow Phenomenon as an Underrecognized and Treatable Source of Chest Pain: Case Series and Literature Review

Background. Coronary slow-flow phenomenon (CSFP) is characterized by delayed distal vessel opacification of contrast, in the absence of significant epicardial coronary stenosis. CSFP has been reported as a cause of chest pain and abnormal noninvasive ischemic tests and is often underrecognized. Material and Methods. Charts and angiographic records from our institution were reviewed to identify 15 consecutive patients who were diagnosed with CSFP from January 2016 to January 2017. Results. Of the 15 patients (4 females and 11 males) studied, the mean age was 59.1 years (range = 45-86 years); all had left ventricular ejection fraction >45% and without significant valvular stenosis/regurgitation. The indication for coronary angiography for all 15 patients was chest pain with abnormal noninvasive tests. Of the 11 patients who underwent previous coronary angiograms, all revealed prior evidence of CSFP. None of these patients were on calcium channel blockers (CCBs) or long-acting nitroglycerin agents before angiography. Intracoronary CCBs were effectively utilized to alleviate the angiographic finding (improvement in Thrombolysis in Myocardial Infarction frame count) in all 15 patients. Oral CCBs were started with subsequent improvement in all 15 patients (mean follow-up time = 13.6 months). Conclusion. Coronary slow-flow should be a diagnostic consideration in patients presenting with chest pain and abnormal noninvasive ischemic testing with nonobstructive epicardial vessels. CSFP remains underrecognized, and the specific standard of care for treatment has not been established. In each of the 15 cases, intracoronary nifedipine resolved the angiographic manifestation of coronary slow-flow. Furthermore, in follow-up, all patients improved symptomatically from their chest pain after oral CCBs were initiated.

Sex differences in the long-term prognostic value of 13N-ammonia myocardial perfusion positron emission tomography

PURPOSE

Evidence to date on the unique female determinants of cardiovascular risk is inadequate. Positron Emission Tomography (PET) is considered to have the highest accuracy for the assessment of myocardial perfusion in patients with suspected coronary artery disease (CAD), but its long-term prognostic accuracy in women has not been established.

METHODS

A total of 619 consecutive patients (138 women, mean age 60.0 ± 11.8 years) underwent clinically indicated ¹³N-ammonia PET at our institution and were followed up (median 5.7 years) for major adverse cardiovascular events (MACE) including cardiac death, nonfatal myocardial infarction, hospitalization for any cardiac reason and late revascularization.

RESULTS

During follow-up, 271 patients had at least one cardiac event, including 64 cardiac deaths and 33 nonfatal myocardial infarctions. In both women and men, abnormal myocardial perfusion was associated with reduced event-free survival (log rank p < 0.001). In women, abnormal myocardial perfusion was associated with a higher risk of a worse outcome than in men (adjusted HR 4.1, 95% CI 1.8-9.0 in women; HR 2.4, 95% CI 1.5-3.8 in men; p_interaction < 0.001). In contrast, abnormal coronary flow reserve (CFR) was a significant predictor of 10-year MACE in men (p = 0.006) but not in women (p = NS). Accordingly, an interaction term of sex and abnormal myocardial perfusion or CFR was significant (p < 0.001).

CONCLUSION

While perfusion findings in ¹³N-ammonia PET provide effective risk stratification in women and men, CFR adds incremental prognostic value for long-term cardiac outcomes only in men. Refined strategies in noninvasive imaging are needed in women to improve CAD risk prediction.

Coronary lumen volume to myocardial mass ratio in primary microvascular angina

BACKGROUND

Microvascular angina (MVA) is an incompletely understood clinical entity. Computational analysis of coronary Computed Tomography Angiography (CTA) has shown an association between low coronary lumen volume to myocardial mass (V/M) ratio and lower Fractional Flow Reserve values, independent of plaque measures. We hypothesized that low V/M ratio may be present in patients with MVA.

METHODS

A retrospective case-control analysis was performed using patients fulfilling guideline criteria for MVA with controls matched for age, gender, coronary risk factors and atherosclerotic plaque burden. V/M was extracted off site (Heartflow Inc; Redwood City, CA) employing allometric scaling laws that allow the definition of the coronary circulation beyond the epicardium. FFR_CT values were calculated in the major epicardial coronary arteries for each group.

RESULTS

A total of 30 patients with MVA and 32 matched controls were included in the study. Mean total coronary lumen volume (2302 mm³ ± 109 vs 2978 mm³ ± 134, p < 0.001) and mean myocardial mass (90.4 g ± 13.7 vs 100.4 g ± 20.1, p = 0.029) were lower in MVA patients compared to controls. Mean V/M ratio was significantly lower in MVA compared to controls (25.6 mm³/g ± 5.9 vs 30.0 mm³/g ± 6.5, p = 0.007; c-statistic 0.69). V/M ratio did not differ significantly between subclasses of angina severity (p = 0.747). No difference in mean nadir FFR_CT values was found between MVA and control groups in the LAD (0.86 ± 0.07 vs 0.83 ± 0.07, p = 0.154), LCX (0.90 ± 0.05 vs 0.90 ± 0.06, p = 0.240) and RCA (0.90 ± 0.04 vs 0.90 ± 0.03, p = 0.773) vessels.

CONCLUSION

Patients with microvascular angina demonstrate a significantly lower coronary CTA-derived coronary volume/myocardial mass ratio than asymptomatic controls.

Women and Ischemic Heart Disease: Recognition, Diagnosis and Management

Cardiovascular disease is one of the most frequent causes of death in both males and females throughout the world. However, women exhibit a greater symptom burden, more functional disability, and a higher prevalence of nonobstructive coronary artery disease (CAD) compared to men when evaluated for signs and symptoms of myocardial ischemia. This paradoxical sex difference appears to be linked to a sex-specific pathophysiology of myocardial ischemia including coronary microvascular dysfunction, a component of the 'Yentl Syndrome'. Accordingly, the term ischemic heart disease (IHD) is more appropriate for a discussion specific to women rather than CAD or coronary heart disease. Following the National Heart, Lung, and Blood Institute Heart Truth/American Heart Association, Women's Ischemia Syndrome Evaluation and guideline campaigns, the cardiovascular mortality in women has been decreased, although significant gender gaps in clinical outcomes still exist. Women less likely undergo testing, yet guidelines indicate that symptomatic women at intermediate to high IHD risk should have further test (e.g. exercise treadmill test or stress imaging) for myocardial ischemia and prognosis. Further, women have suboptimal use of evidence-based guideline therapies compared with men with and without obstructive CAD. Anti-anginal and anti-atherosclerotic strategies are effective for symptom and ischemia management in women with evidence of ischemia and nonobstructive CAD, although more female-specific study is needed. IHD guidelines are not "cardiac catheterization" based but related to evidence of "myocardial ischemia and angina". A simplified approach to IHD management with ABCs (aspirin, angiotensin-converting enzyme inhibitors/angiotensin-renin blockers, beta blockers, cholesterol management and statin) should be used and can help to increases adherence to guidelines.

Cardiac Syndrome X: Update

Cardiac Syndrome X (CSX), characterized by angina-like chest discomfort, ST segment depression during exercise, and normal epicardial coronary arteries at angiography, is highly prevalent in women. CSX is not benign, and linked to adverse cardiovascular outcomes and a poor quality of life. Coronary microvascular and endothelial dysfunction and abnormal cardiac nociception have been implicated in the pathogenesis of CSX. Treatment includes life-style modification, anti-anginal, anti-atherosclerotic, and anti-ischemic medications. Non-pharmacological options include cognitive behavioral therapy, enhanced external counterpulsation, neurostimulation, and stellate ganglionectomy. Studies have shown the efficacy of individual treatments but guidelines outlining the best course of therapy are lacking.

Unexplained Chest Pain and Physical Activity: Balancing Between Existential Uncertainty and Certainty

Chest pain is one of the most common complaints in medical settings, but the majority of cases have no detectable cause. Physical activity is recommended, but is one of the major avoidance behaviors in patients with coronary heart disease. The article aims at achieving an understanding of the meaning of physical activity for people with unexplained chest pain. Fifteen people were interviewed using a phenomenological hermeneutic approach, with the results revealing four themes: "awareness of the influence of previous life experiences on the decision to be physically active," "unanswered questions related to physical activity and unexplained chest pain," "intertwinement of body and mind," and "physical activity as a source of personal growth." Comprehensive understanding was formulated as "Being physically active while living with unexplained chest pain means balancing between existential uncertainty and certainty." The results are discussed in relation to capability. It is suggested that health professionals adopt a person-centered approach.

Sex differences in the pathophysiology, treatment, and outcomes in IHD

Heart disease is the number one killer of women. Although there are many similarities between men and women, the evolving understanding of ischemic heart disease in women allow us to emphasize the important differences that need to be recognized. These differences, including symptoms at presentation, importance of particular risk factors, pathophysiology of disease, and treatments/outcomes, will be discussed in this review.

Emergence of Nonobstructive Coronary Artery Disease: A Woman's Problem and Need for Change in Definition on Angiography

Recognition of ischemic heart disease (IHD) is often delayed or deferred in women. Thus, many at risk for adverse outcomes are not provided specific diagnostic, preventive, and/or treatment strategies. This lack of recognition is related to sex-specific IHD pathophysiology that differs from traditional models using data from men with flow-limiting coronary artery disease (CAD) obstructions. Symptomatic women are less likely to have obstructive CAD than men with similar symptoms, and tend to have coronary microvascular dysfunction, plaque erosion, and thrombus formation. Emerging data document that more extensive, nonobstructive CAD involvement, hypertension, and diabetes are associated with major adverse events similar to those with obstructive CAD. A central emerging paradigm is the concept of nonobstructive CAD as a cause of IHD and related adverse outcomes among women. This position paper summarizes currently available knowledge and gaps in that knowledge, and recommends management options that could be useful until additional evidence emerges.

Microvascular angina: an update on diagnosis and treatment

ABSTRACT 

Many patients with chest pain who are relieved to learn that they have no obstructive stenoses at diagnostic angiography are misclassified as having noncardiac chest pain. Only recently have we developed the conceptual framework and diagnostic tools to understand that ischemic heart disease is not exclusively caused by obstructive coronary artery disease, but often has its origin in the microcirculation. This article will focus on the diagnosis and treatment of microvascular angina as a cause of myocardial ischemia in patients with abnormal but ‘normal appearing’ coronary arteries.

Pilot study testing the effect of physical training over the myocardial perfusion and quality of life in patients with primary microvascular angina

BACKGROUND

Primary microvascular angina (PMA) is a common clinical condition associated to negative impact on quality of life (QOL) and reduced physical capacity. This study aimed at evaluating the effects of aerobic physical training (APT) on myocardial perfusion, physical capacity, and QOL in patients with PMA.

METHODS

We investigated 12 patients (53.8 ± 9.7 years old; 7 women) with PMA, characterized by angina, angiographycally normal coronary arteries, and reversible perfusion defects (RPDs) detected on (99m)Tc-sestamibi-SPECT myocardial perfusion scintigraphy (MPS). At baseline and after 4 month of APT, the patients underwent MPS, cardiopulmonary test, and QOL questionnaire. Stress-rest MPS images were visually analyzed by attributing semi-quantitative scores (0 = normal; 4 = absent uptake), using a 17-segment left ventricular model. Summed stress, rest, and difference scores (SDS) were calculated.

RESULTS

In comparison to the baseline, in the post-training we observed a significant increase in peak-VO2 (19.4 ± 4.8 and 22.1 ± 6.2 mL·kg(-1)·minute(-1), respectively, P = .01), reduction of SDS (10.1 ± 8.8 and 2.8 ± 4.9, P = .008), and improvement in QOL scores.

CONCLUSIONS

Physical training in patients with PMA is associated with reduction of myocardial perfusion abnormalities, increasing of physical capacity, and improvement in QOL. The findings of this hypothesis-generating study suggest that APT can be a valid therapeutic option for patients with PMA.

Ageing and microvasculature

A decline in the function of the microvasculature occurs with ageing. An impairment of endothelial properties represents a main aspect of age-related microvascular alterations. Endothelial dysfunction manifests itself through a reduced angiogenic capacity, an aberrant expression of adhesion molecules and an impaired vasodilatory function. Increased expression of adhesion molecules amplifies the interaction with circulating factors and inflammatory cells. The latter occurs in both conduit arteries and resistance arterioles. Age-related impaired function also associates with phenotypic alterations of microvascular cells, such as endothelial cells, smooth muscle cells and pericytes. Age-related morphological changes are in most of cases organ-specific and include microvascular wall thickening and collagen deposition that affect the basement membrane, with the consequent perivascular fibrosis. Data from experimental models indicate that decreased nitric oxide (NO) bioavailability, caused by impaired eNOS activity and NO inactivation, is one of the causes responsible for age-related microvascular endothelial dysfunction. Consequently, vasodilatory responses decline with age in coronary, skeletal, cerebral and vascular beds. Several therapeutic attempts have been suggested to improve microvascular function in age-related end-organ failure, and include the classic anti-atherosclerotic and anti-ischemic treatments, and also new innovative strategies. Change of life style, antioxidant regimens and anti-inflammatory treatments gave the most promising results. Research efforts should persist to fully elucidate the biomolecular basis of age-related microvascular dysfunction in order to better support new therapeutic strategies aimed to improve quality of life and to reduce morbidity and mortality among the elderly patients.

Cardiac Syndrome X: update 2014

Cardiac Syndrome X (CSX), characterized by angina-like chest discomfort, ST segment depression during exercise, and normal epicardial coronary arteries at angiography, is highly prevalent in women. CSX is not benign, and linked to adverse cardiovascular outcomes and a poor quality of life. Coronary microvascular and endothelial dysfunction and abnormal cardiac nociception have been implicated in the pathogenesis of CSX. Treatment includes life-style modification, anti-anginal, anti-atherosclerotic, and anti-ischemic medications. Non-pharmacological options include cognitive behavioral therapy, enhanced external counterpulsation, neurostimulation, and stellate ganglionectomy. Studies have shown the efficacy of individual treatments but guidelines outlining the best course of therapy are lacking.

Sex-specific factors in microvascular angina

In women presenting for evaluation of suspected ischemic symptoms, a diagnosis of normal coronary arteries is 5 times more common than it is in men. These women are often labelled as having cardiac syndrome X, and a subset of them have microvascular angina caused by microvascular coronary dysfunction (MCD). MCD is not benign and is associated with an annual 2.5% cardiac event rate. Noninvasive testing for MCD remains insensitive, although newer imaging modalities, such as adenosine cardiac magnetic resonance imaging, appear promising. The gold standard for diagnosis of MCD is coronary reactivity testing, an invasive technique that is not available in many countries. With regard to treatment, large-scale trials are lacking. Although research is ongoing, the current platform of therapy consists of antiangina, antiplatelet, and endothelium-modifying agents (primarily angiotensin-converting enzyme inhibitors and statins).

Coronary microvascular dysfunction: an update

Many patients undergoing coronary angiography because of chest pain syndromes, believed to be indicative of obstructive atherosclerosis of the epicardial coronary arteries, are found to have normal angiograms. In the past two decades, a number of studies have reported that abnormalities in the function and structure of the coronary microcirculation may occur in patients without obstructive atherosclerosis, but with risk factors or with myocardial diseases as well as in patients with obstructive atherosclerosis; furthermore, coronary microvascular dysfunction (CMD) can be iatrogenic. In some instances, CMD represents an epiphenomenon, whereas in others it is an important marker of risk or may even contribute to the pathogenesis of cardiovascular and myocardial diseases, thus becoming a therapeutic target. This review article provides an update on the clinical relevance of CMD in different clinical settings and also the implications for therapy.

Ischemic heart disease in women

Cardiovascular disease is the leading cause of death in women. Although overall mortality from coronary heart disease (CHD) has decreased, there are subsets of patients, particularly young women, in whom the mortality rate has increased. Underlying sex differences in CHD may be an explanation. Women have more frequent symptoms, more ischemia, and higher mortality than men, but less obstructive coronary artery disease (CAD). Despite this, traditional risk factor assessment has been ineffective in risk stratifying women, prompting the emergence of novel markers and prediction scores to identify a population at risk. Sex differences in manifestations and the pathophysiology of CHD also have led to differences in the selection of diagnostic testing and treatment options for women, having profound effects on outcomes. The frequent finding of nonobstructive CAD in women with ischemia suggests microvascular dysfunction as an underlying cause; therefore, coronary reactivity and endothelial function testing may add to diagnostic accuracy in female patients. In spite of evidence that women benefit from the same therapies as men, they continue to receive less-aggressive therapy, which is reflected in higher healthcare resource utilization and adverse outcomes. More sex-specific research is needed in the area of symptomatic nonobstructive CAD to define the optimal therapeutic approach.

Evolving strategies for the treatment of microvascular angina in women

Microvascular angina, also known as cardiac syndrome X, is characterized by anginal chest pain, at least one cardiovascular risk factor, an abnormal stress test and normal coronary arteries on angiography. It is significantly more common in women than in men. A definitive diagnosis of microvascular angina can be made by invasive or noninvasive methods; a presumptive diagnosis can also be made based on fulfillment of diagnostic criteria. Effective treatment of microvascular angina requires aggressive risk factor modification; exercise is one of the most effective treatment modalities. Several other treatment strategies have been shown to relieve anginal symptoms as well as improve vascular function; these include β-blockers, angiotensin-converting enzyme inhibitors, ranolazine, L-arginine, statin drugs and potentially estrogen replacement therapy. Nitrates may be effective for symptom relief. Further studies are required to determine whether specific treatments are associated with improved survival as well as decreased symptoms.

Myocardial ischemia in women: lessons from the NHLBI WISE study

Cardiovascular disease (CVD) remains the leading cause of death for women. For almost 3 decades, more women than men have died from CVD, with the most recent annual statistics on mortality reporting that CVD accounted for 421 918 deaths among women in the United States. Although there have been significant declines in coronary heart disease (CHD) mortality for females, these reductions lag behind those seen in men. In addition, where there has been a decrease in mortality from CHD across all age groups over time in men, in the youngest women (age <55 years) there has been a notable increase in mortality from CHD. There are differences in the prevalence, symptoms, and pathophysiology of myocardial ischemia that occurs in women compared with men. In this paper, we review the pathophysiology and mechanisms of ischemic heart disease (IHD) in women, particularly focusing on what we have learned from the WISE study. We examine the sex-specific issues related to myocardial ischemia in women in terms of prevalence and prognosis, traditional and novel risk factors, diagnostic testing, as well as therapeutic management strategies for IHD.

Microvascular coronary dysfunction in women: pathophysiology, diagnosis, and management

Women exhibit a greater symptom burden, more functional disability, and a higher prevalence of no obstructive coronary artery disease compared to men when evaluated for signs and symptoms of myocardial ischemia. Microvascular coronary dysfunction (MCD), defined as limited coronary flow reserve and/or coronary endothelial dysfunction, is the predominant etiologic mechanism of ischemia in women with the triad of persistent chest pain, no obstructive coronary artery disease, and ischemia evidenced by stress testing. Evidence shows that approximately 50% of these patients have physiological evidence of MCD. MCD is associated with a 2.5% annual major adverse event rate that includes death, nonfatal myocardial infarction, nonfatal stroke, and congestive heart failure. Although tests such as adenosine stress cardiac magnetic resonance imaging may be a useful noninvasive method to predict subendocardial ischemia, the gold standard test to diagnose MCD is an invasive coronary reactivity testing. Early identification of MCD by coronary reactivity testing may be beneficial in prognostication and stratifying these patients for optimal medical therapy. Currently, understanding of MCD pathophysiology can be used to guide diagnosis and therapy. Continued research in MCD is needed to further advance our understanding.

Angina in Women without Obstructive Coronary Artery Disease

Angina in the absence of obstructive coronary artery disease, sometimes referred to as cardiac syndrome X (CSX), is a debilitating condition that disproportionately affects women. More than 50% of women evaluated for angina have non-obstructive disease by cardiac catheterization, although the total numbers of women affected by CSX are unknown. Varying clinical definitions and the lack of large scale epidemiologic studies focusing on this illness have resulted in limited knowledge about its risk factors, although there appears to be an association with black race, estrogen deficiency, and insulin resistance. Contrary to prior beliefs about the benign nature of this entity, these women suffer considerable morbidity with costly economic implications that approach the lifetime costs of healthcare utilization for those with obstructive coronary disease. Two prevailing hypotheses have emerged to explain CSX: the ischemic hypothesis detailing abnormal coronary microvascular function and the non-ischemic hypothesis describing altered pain perception and myocardial hypersensitivity. Treatment strategies have focused on both of these pathways with the main goal of improving symptoms. Beta blockers provide the most convincing evidence for benefit, with other antianginals having secondary roles. Other promising pharmacologic therapies include xanthine derivatives, estrogen replacement therapy, ACE inhibitors, and statin medications, among other emerging treatment options. Neurostimulation and lifestyle factors including exercise can also be beneficial in reducing symptoms. However, managing patients with CSX can be frustrating for both patients and physicians, as there is a lack of data regarding an optimal treatment algorithm including few large-scale randomized controlled trials to clarify effective therapies.

A randomized controlled trial of low-dose hormone therapy on myocardial ischemia in postmenopausal women with no obstructive coronary artery disease: results from the National Institutes of Health/National Heart, Lung, and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation (WISE)

BACKGROUND

Compared with men, women have more evidence of myocardial ischemia with no obstructive coronary artery disease. Although low endogenous estrogen levels are associated with endothelial dysfunction, the role of low-dose hormone therapy has not been fully evaluated. We postulate that a 12-week duration of low-dose hormone replacement therapy is associated with myocardial ischemia and endothelial dysfunction.

METHODS AND RESULTS

Using a multicenter, randomized, placebo-controlled design, subjects were randomized to receive either 1 mg norethindrone/10 microg ethinyl estradiol or placebo for 12 weeks. Chest pain and menopausal symptoms, cardiac magnetic resonance spectroscopy, brachial artery reactivity, exercise stress testing, and psychosocial questionnaires were evaluated at baseline and exit. Recruitment was closed prematurely because of failure to recruit after publication of the Women's Health Initiative hormone trial. Of the 35 women who completed the study, there was less frequent chest pain in the treatment group compared with the placebo group (P = .02) at exit. Women taking 1 mg norethindrone/10 microg ethinyl estradiol also had significantly fewer hot flashes/night sweats (P = .003), less avoidance of intimacy (P = .05), and borderline differences in sexual desire and vaginal dryness (P = .06). There were no differences in magnetic resonance spectroscopy, brachial artery reactivity, compliance, or reported adverse events between the groups.

CONCLUSIONS

These data suggest that low-dose hormone therapy improved chest pain symptoms, menopausal symptoms, and quality of life, but did not improve ischemia or endothelial dysfunction. Given that it was not possible to enroll the prespecified sample size, these results should not be considered definitive.

Cardiac syndrome X: current concepts

Cardiac syndrome X is a heterogeneous entity, both clinically and pathophysiologically, encompassing a variety of pathogenic mechanisms. Management of this syndrome represents a major challenge to the treating physician. They often seek medical care because of recurring and disabling chest pain, which may imply repetitive and costly invasive and non-invasive investigations. A careful patient evaluation for underlying pathophysiologic mechanism and exclusion of other causes of chest pain along with attention to various psychological aspects is helpful in reducing the stress and suffering of these patients. This article reviews the available literature on the pathophysiology and current controversies surrounding the management of this difficult to treat condition.

Women and ischemic heart disease: evolving knowledge

Evolving knowledge regarding sex differences in coronary heart disease is emerging. Given the lower burden of obstructive coronary artery disease (CAD) and preserved systolic function in women, which contrasts with greater rates of myocardial ischemia and near-term mortality compared with men, we propose the term "ischemic heart disease" as appropriate for this discussion specific to women rather than CAD or coronary heart disease (CHD). This paradoxical difference, where women have lower rates of anatomical CAD but more symptoms, ischemia, and adverse outcomes, appears linked to abnormal coronary reactivity that includes microvascular dysfunction. Novel risk factors can improve the Framingham risk score, including inflammatory markers and reproductive hormones, as well as noninvasive imaging and functional capacity measurements. Risk for women with obstructive CAD is increased compared with men, yet women are less likely to receive guideline-indicated therapies. In the setting of non-ST-segment elevation acute myocardial infarction, interventional strategies are equally effective in biomarker-positive women and men, whereas conservative management is indicated for biomarker-negative women. For women with evidence of ischemia but no obstructive CAD, antianginal and anti-ischemic therapies can improve symptoms, endothelial function, and quality of life; however, trials evaluating impact on adverse outcomes are needed. We hypothesize that women experience more adverse outcomes compared with men because obstructive CAD remains the current focus of therapeutic strategies. Continued research is indicated to devise therapeutic regimens to improve symptom burden and reduce risk in women with ischemic heart disease.

Microvascular angina and the continuing dilemma of chest pain with normal coronary angiograms

Since initial reports over 4 decades ago, cases of patients with angina-like chest pain whose coronary angiograms show no evidence of obstructive coronary artery disease and who have no structural heart disease continue to be a common occurrence for cardiologists. Many features of this patient population have remained constant with successive reports over time: a female predominance, onset of symptoms commonly between 40 and 50 years of age, pain that is severe and disabling, and inconsistent responses to conventional anti-ischemic therapy. Because patients may have had abnormal noninvasive testing that led to performance of coronary angiography, investigators have sought to show an association of this syndrome with myocardial ischemia. Abnormalities in coronary flow and metabolic responses to stress have been reported by several groups, findings consistent with a microvascular etiology for ischemia and symptoms, but others have questioned the presence of ischemia, even in patients selected for abnormal noninvasive testing. Despite considerable efforts by many groups over 4 decades, the syndrome remains controversial with regard to pathophysiology, diagnosis, and management.

Adverse cardiovascular outcomes in women with nonobstructive coronary artery disease: a report from the Women's Ischemia Syndrome Evaluation Study and the St James Women Take Heart Project

BACKGROUND

Women with clinical findings suggestive of ischemia but without findings of obstructive coronary artery disease (CAD) on angiography represent a frequent clinical problem; predicting prognosis is challenging.

METHODS

The Women's Ischemia Syndrome Evaluation (WISE) study examined symptomatic women referred for clinically indicated coronary angiography and followed up for a mean 5.2 years. The St James Women Take Heart (WTH) Project enrolled asymptomatic, community-based women with no history of heart disease who were followed up for 10 years. We compared cardiovascular events (ie, myocardial infarction, stroke, and hospitalization for heart failure) and death in 540 WISE women with suspected ischemia but no angiographic evidence of obstructive CAD with those from a cohort of 1000 age- and race-matched WTH women.

RESULTS

Compared with the WISE women, asymptomatic WTH women had a lower prevalence of obesity, family history of CAD, hypertension, and diabetes mellitus (P < .001). Five-year annualized event rates for cardiovascular events were 16.0% in WISE women with nonobstructive CAD (stenosis in any coronary artery of 1%-49%), 7.9% in WISE women with normal coronary arteries (stenosis of 0% in all coronary arteries), and 2.4% in asymptomatic WTH women (P < or = .002), after adjusting for baseline CAD risk factors. The cardiovascular events were most frequent in women with 4 or more cardiac risk factors, with the 5-year annualized cardiovascular event rate being 25.3% in women with nonobstructive CAD, 13.9% in WISE women with normal coronary arteries, and 6.5% in asymptomatic women (P = .003).

CONCLUSION

Women with symptoms and signs suggestive of ischemia but without obstructive CAD are at elevated risk for cardiovascular events compared with asymptomatic community-based women.