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

The influence of sex on microvascular function

A number of studies consistently report higher rates of all clinical outcomes including postinfarction mortality, need for repeat revascularization, and reinfarction in women with cardiovascular diseases than in men. As well, the gender gap in the prevalence of cardiovascular diseases decreases progressively with increasing age. Yet, the diagnosis and treatment of these diseases differ between genders and women remain underdiagnosed for coronary heart disease. In a recent retrospective analysis we showed that, along with vessel under study and age, gender is a determinant of adenosine responses during studies of fractional flow reserve, an effect that was probably due to differences in microvascular function and that influenced the interpretation of fractional flow reserve data. These data demonstrate that not only the clinical presentation is different, but also the diagnostic approach to coronary artery disease might differ between sexes.A gap still exists in the understanding of the mechanisms, awareness, and treatment of coronary artery disease in women, but also, as we show, in the application of diagnostic modalities that are well established in men.

Association of CYP2C19 variants and epoxyeicosatrienoic acids on patients with microvascular angina

Categorization as a cytochrome P450 (CYP) 2C19 poor metabolizer (PM) is reported to be an independent risk factor for cardiovascular disease. Epoxyeicosatrienoic acids (EETs) are metabolites of arachidonic acid by CYP2C19 epoxygenases and anti-inflammatory properties, especially in microvascular tissues. We examined the association of CYP2C19 polymorphisms and EETs on microvascular angina (MVA) caused by coronary microvascular dysfunction. We examined CYP2C19 genotypes in patients with MVA ( n = 71) and healthy subjects as control ( n = 71). MVA was defined as the absence of coronary artery stenosis and epicardial spasms and the presence of inversion of lactic acid levels between intracoronary and coronary sinuses in acetylcholine-provocation test or the adenosine-triphosphate-induced coronary flow reserve ratio was below 2.5. CYP2C19 PM have two loss-of-functon alleles (*2, *3). We measured serum dihydroxyeicosatrienoic acid (DHET) as representative EET metabolite. MVA group showed significantly higher CYP2C19 PM incidence (35% vs. 16%; P = 0.007) and high sense C-reactive protein (hs-CRP) levels (0.127 ± 0.142 vs. 0.086 ± 0.097 mg/dl; P = 0.043) than those of controls. Moreover, in MVA group, hs-CRP levels in CYP2C19 PM were significantly higher than that of non-PM (0.180 ± 0.107 vs. 0.106 ± 0.149 mg/dl, P = 0.045). Multivariate analysis indicated that smoking, hypertension, high hs-CRP, and CYP2C19 PM are predictive factors for MVA. In MVA group, DHET levels for CYP2C19 PM were significantly lower than that of non-PM [10.9 ± 1.64 vs. 14.2 ± 5.39 ng/ml, P = 0.019 (11,12-DHET); 15.2 ± 4.39 vs. 17.9 ± 4.73 ng/ml, P = 0.025 (14,15-DHET)]. CYP2C19 variants are associated with MVA. The decline of EET-based defensive mechanisms owing to CYP2C19 variants may affect coronary microvascular dysfunction.

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.

The Challenges of Prevention, Diagnosis and Treatment of Ischemic Heart Disease in Women

Increasing evidence suggests that there are significant differences in the presentation, diagnosis and treatment of ischemic heart disease in women compared to men. Women often present with atypical symptoms, and this, in association with a consistent underestimation of their risk for ischemic heart disease, leads to underdiagnosis and undertreatment in women. Cardiovascular risk factors unique to women have only recently been recognized, and moreover, traditional risk factors have recently been shown to have greater impacts on women. Consequently, women suffer more disability and poorer clinical outcomes, with higher cardiovascular morbidity and mortality. These discrepancies may in part be secondary to the higher prevalence of nonobstructive coronary artery disease in women with persistent chest pain symptoms as compared to men when evaluated invasively. Focused diagnostic and therapeutic strategies unique to women are thus needed, but unfortunately, such sex-specific guidelines do not yet exist, largely due to lack of awareness, both on the part of providers and patients, as well as a paucity of evidence-based research specific to women. Although underutilized in women, diagnostic modalities, including functional and anatomic cardiac tests as well as physiologic assessments of endothelial and microvascular function, are useful for establishing the diagnosis and prognosis of suspected ischemic heart disease in women. This review discusses the current challenges of prevention, diagnosis and treatment of ischemic heart disease in women.

Sex differences in the impact of CYP2C19 polymorphisms and low-grade inflammation on coronary microvascular disorder

Categorization as a cytochrome P-450 (CYP) 2C19 poor metabolizer (PM) is reported to be an independent risk factor for cardiovascular disease. It is correlated with an increase in the circulating levels of high-sense C-reactive protein (hs-CRP) in women only, although its role in coronary microcirculation is unclear. We examined sex differences in the impact of the CYP2C19 genotype and low-grade inflammation on coronary microvascular disorder (CMVD). We examined CYP2C19 genotypes in patients with CMVD (n = 81) and in healthy subjects as control (n = 81). CMVD was defined as the absence of coronary artery stenosis and epicardial spasms, the presence of inverted lactic acid levels between the intracoronary and coronary sinuses, or an adenosine triphosphate-induced coronary flow reserve ratio < 2.5. CYP2C19 PMs have two loss-of-function (LOF) alleles (*2, *3). Extensive metabolizers have no LOF alleles, and intermediate metabolizers have one LOF allele. The ratio of CYP2C19 PM and hs-CRP levels in CMVD was significantly higher than that of controls, especially in women (40.9 vs. 13.8%, P = 0.013; 0.11 ± 0.06 vs. 0.07 ± 0.04 mg/dl, P = 0.001). Moreover, in each CYP2C19 genotype, hs-CRP levels in CMVD in CYP2C19 PMs were significantly higher than those of the controls, especially in women (0.15 ± 0.06 vs. 0.07 ± 0.03, P = 0.004). Multivariate analysis for CMVD indicated that the female sex, current smoking, and hypertension were predictive factors, and that high levels of hs-CRP and CYP2C19 PM were predictive factors in women only (odds ratio 3.5, 95% confidence interval 1.26-9.93, P = 0.033; odds ratio 4.1, 95% confidence interval 1.15-14.1, P = 0.038). CYP2C19 PM genotype may be a new candidate risk factor for CMVD via inflammation exclusively in the female population.

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.

The association of severity of retinal vascular changes and cardiac remodelling in systemic hypertension

OBJECTIVES

The aim of the study was to explore the association between hypertensive retinopathy, grades of retinopathy and cardiac remodelling.

METHODS

This was a cross-sectional observational study. A total of 500 consecutive hypertensive adults from the in-patient population were studied for the presence of hypertensive retinopathy by dilated fundoscopy. The presence of cardiac remodelling due to hypertension was studied both by electrocardiography (ECG) and echocardiography. Hypertensive target organ damage in other organs was also screened. In addition, the association of grades of hypertensive retinopathy with target organ damage was also analyzed.

RESULTS

Systolic blood pressure (BP) at presentation and duration of hypertension showed no relationship with markers of hypertensive heart disease. However, diastolic BP was significantly higher in patients with retinopathy. Hypertensive retinopathy was diagnosed in 324 subjects of whom 90 had grades 3 and 4 retinopathy. Patients with grades 3 and 4 retinopathy had significant associations with ECG evidence of left ventricular (LV) strain pattern and left atrial enlargement, and a weaker association with left ventricular hypertrophy (LVH) using QRS voltage criteria (Sokolov-Lyon). On echocardiography, grades 3 and 4 retinopathy were significantly associated with LVH, left atrial enlargement and reduced left ventricular ejection fraction (LVEF), as well as with higher creatinine values. A large number of these patients presented with heart failure. Cardiac remodelling was not seen in patients without retinopathy and was uncommon in patients with grades 1 and 2 retinopathy.

CONCLUSION

Grades 3 and 4 retinopathy demonstrated a significant association with LV strain pattern and left atrial enlargement on ECG, LVH and reduced LVEF on echocardiography as well as with heart failure. There was no relationship with systolic BP and duration of hypertension, while diastolic BP showed a significant positive correlation. Signs of hypertensive heart disease were practically absent in patients without hypertensive retinopathy and uncommon in those with grade 1-2 alterations.

Instrumento para la valoración de síntomas coronarios en la mujer

<p>Objetivo: Diseñar y validar un instrumento para la valoración de los síntomas en la mujer con enfermedad coronaria, enmarcada en la Teoría de los Síntomas Desagradables Metodología: Estudio metodológico, psicométrico, orientado por los Síntomas, concepto central de la Teoría de los Síntomas Desagradables de Lenz y colaboradores. Se realizó una crítica teórica del constructo elegido, demostrando su utilidad en la investigación y en la práctica disciplinar. Se ponderaron 260 evidencias por medio de una rigurosa crítica metodológica y empírica, aplicando el Sistema de Revisión Integrativa articulada al Modelo Conceptual Empírico de Fawcett y Garity. Se obtuvieron 30 piezas investigativas utilizadas para la construcción de los ítems. A los síntomas de Lenz se suman los síntomas psicosociales reportados en mujeres con enfermedad coronaria, generándose un primer instrumento compuesto por 87 ítems. Resultados: Se realizó una Validación de Contenido de expertos: Modelo Escobar y Cuervo 2008 (análisis estadístico SPSS 20) obteniéndose un Coeficiente de Correlación de Kendall de 0,682 (0,05), con buena concordancia entre jueces. El Modelo de Lawshe normalizado por Tristán 2008 reportó una Content Validity Ratio de 0,57 y un Index Validity Content de 0,797, demostrando que los ítems son unidades de análisis esenciales. Finalmente, la Validación Facial realizada mediante una prueba piloto a 21 mujeres que cumplieron los criterios de inclusión permitió la discriminación semiótica de los ítems, obteniéndose un instrumento compuesto por 67 ítems. Conclusiones: Éste es un remanente investigativo que requiere nuevas validaciones para elevar su capacidad psicométrica.</p>

Electrocardiographic predictors of coronary microvascular dysfunction in patients with non-obstructive coronary artery disease: Utility of a novel T wave analysis program

BACKGROUND

Coronary microvascular dysfunction (CMD) is linked to adverse cardiovascular events. Definitive diagnosis of CMD requires invasive provocative testing during angiography. We developed and tested a novel computerized T wave analysis tool to identify electrocardiographic signatures of CMD.

METHODS

1552 patients underwent an invasive assessment of coronary microvascular function. Patients with interpretable pre-procedural ECGs were divided into 2 age and sex matched groups (n=261 in each group, 75% female): normal microvascular function, CFR>2.5 (CFR+), and abnormal microvascular function, CFR ≤ 2.5 (CFR-). ECGs were evaluated using a novel T wave program that quantified subtle changes in T wave morphology.

RESULTS

T wave repolarization parameters were significantly different between patients with normal and abnormal microvascular function. The top 3 features in males comprised of T wave area in V6 (CFR+: 10091.4 mV(2) vs. CFR-: 8152.3 mV(2), p<0.05); T1 Y-center of gravity in lead II (CFR+: 17.8 mV vs. CFR-: 22.4, p<0.005) and T Peak-T End in lead II (CFR+: 97.6 msec vs. CFR-: 91.1 msec, p<0.05). These could identify the presence of an abnormal CFR with 74 ± 0.2% accuracy. In females, the top 3 features were T wave right slope lead V6 (CFR+: -2489.1 mV/msec vs. CFR-: -2352.3 mV/msec, p<0.005); Amplitude in V6 (CFR+: 190.4 mV vs. 172.7 mV, p=0.05) and Y-center of gravity in lead V1 (CFR+: 33.3 vs. CFR-: 40.0, p=0.001). These features could identify the presence of an abnormal CFR with 67 ± 0.3% accuracy.

CONCLUSION

Our data demonstrates that a computer-based repolarization measurement tool may identify electrocardiographic signatures of CMD.

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.

Diagnosis of coronary microvascular dysfunction - Present status

Definite clinical diagnosis of microvascular angina is not possible with the existing knowledge. Resting electrocardiogram may be normal, and exercise electrocardiogram may be unremarkable. Echocardiography usually does not show regional wall motion abnormalities. Transthoracic Doppler echocardiography can satisfactorily evaluate only left anterior descending coronary artery and that too in some patients. Radio-isotope imaging can detect only severe localized disease. Noninvasive diagnosis needs high index of suspicion. At present, definite diagnosis is based on documentation of normal epicardial coronaries, coronary flow reserve less than 2.5 on adenosine induced hyperemia, and absence of spasm of epicardial coronaries on acetylcholine provocation. Invasive evaluation is costly, needs sophisticated equipments and expertise. Therapeutic and prognostic implications of various parameters remains to be evaluated. At present invasive evaluation is recommended only for patients with intractable symptoms with unconfirmed diagnosis, requiring repeated hospitalization and evaluation with failure of empirical therapy.

Coronary microvascular dysfunction is associated with baseline QTc prolongation amongst patients with chest pain and non-obstructive coronary artery disease

BACKGROUND

Coronary microvascular dysfunction (CMD) causes ischemia and is linked to adverse cardiovascular events. Acute transmural ischemia is associated with QT prolongation, but whether CMD affects repolarization is unknown. The aim of this study was to determine if CMD is associated with prolongation of resting heart rate corrected QT interval (QTc).

METHODS

In patients presenting to the catheterization laboratory with chest pain and non-obstructive coronary artery disease (CAD) at angiography, coronary flow reserve (CFR) in response to intracoronary adenosine was measured and compared to baseline to give a CFR ratio. The Bazett's-derived QTc was manually derived from patients' 12-lead ECG obtained prior to the procedure. QTc was compared between patients with normal and abnormal (CFR ratio≤2.5) coronary microvascular function.

RESULTS

Of the 926 patients included in this study, 281 patients (30%) had CMD (mean age 53.2 years [SD 12.7], 25% male). QTc was significantly longer in those with an abnormal CFR response to adenosine (median [Q1, Q3] ms: 420 [409, 438] vs. 416 [405, 432]; p value<0.001) and patients in the lowest quartile of CFR had a significantly longer QTc compared to those in the highest quartile (median [Q1, Q3] ms: 420 [409, 439] vs. 413 [402, 426]; p<0.001). In a linear regression model adjusting for age and sex, CMD was associated with an increase in QTc of 3.09 ms (p=0.055).

CONCLUSION

Our data suggest that CMD may be associated with an increase in baseline QTc, however the precise clinical relevance of this finding needs to be better investigated in larger clinical studies.

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.

Coronary microvascular dysfunction: sex-specific risk, diagnosis, and therapy

Cardiovascular disease is the leading cause of death worldwide. In the presence of signs and symptoms of myocardial ischaemia, women are more likely than men to have no obstructive coronary artery disease (CAD). Women have a greater burden of symptoms than men, and are often falsely reassured despite the presence of ischaemic heart disease because of a lack of obstructive CAD. Coronary microvascular dysfunction should be considered as an aetiology for ischaemic heart disease with signs and symptoms of myocardial ischaemia, but no obstructive CAD. Coronary microvascular dysfunction is defined as impaired coronary flow reserve owing to functional and/or structural abnormalities of the microcirculation, and is associated with an adverse cardiovascular prognosis. Therapeutic lifestyle changes as well as antiatherosclerotic and antianginal medications might be beneficial, but clinical outcome trials are needed to guide treatment. In this Review, we discuss the prevalence, presentation, diagnosis, and treatment of coronary microvascular dysfunction, with a particular emphasis on ischaemic heart disease in women.

Etiopathogenesis of microvascular angina: caveats in our knowledge

Nearly 50% of subjects of coronary artery disease suffer from coronary microvascular dysfunction. Various etiopathogenetic factors have been proposed by different workers but no hypothesis can explain the genesis of microvascular angina in all patients. We have made an attempt to review the literature to find caveats in our knowledge so that future studies can be better designed.

Coronary Microvascular Function and Beyond: The Crosstalk between Hormones, Cytokines, and Neurotransmitters

Beyond its hemodynamic function, the heart also acts as a neuroendocrine and immunoregulatory organ. A dynamic communication between the heart and other organs takes place constantly to maintain cardiovascular homeostasis. The current understanding highlights the importance of the endocrine, immune, and nervous factors to fine-tune the crosstalk of the cardiovascular system with the entire body. Once disrupted, this complex interorgan communication may promote the onset and the progression of cardiovascular diseases. Thus, expanding our knowledge on how these factors influence the cardiovascular system can lead to novel therapeutic strategies to improve patient care. In the present paper, we review novel concepts on the role of endocrine, immune, and nervous factors in the modulation of microvascular coronary function.

Current Diagnostic and Therapeutic Strategies in Microvascular Angina

Microvascular angina is common among patients with signs and symptoms of acute coronary syndrome and is associated with an increased risk of cardiovascular and cerebrovascular events. Unfortunately, microvascular is often under-recognized in clinical settings. The diagnosis of microvascular angina relies on assessment of the functional status of the coronary microvasculature. Invasive strategies include acetylcholine provocation, intracoronary Doppler ultrasound, and intracoronary thermodilution; noninvasive strategies include cardiac positron emission tomography (PET), cardiac magnetic resonance, and Doppler echocardiography. Once the diagnosis of microvascular angina is established, treatment is focused on improving symptoms and reducing future risk of cardiovascular and cerebrovascular events. Pharmacologic options and lifestyle modifications for patients with microvascular angina are similar to those for patients with coronary artery disease.

Single nucleotide polymorphisms associated with abnormal coronary microvascular function

BACKGROUND

Single nucleotide polymorphisms (SNPs) are the most common source of genetic variation. Although microvascular pathology is associated with cardiovascular events, genetic phenotypes causing microvascular disease remain largely unknown. This study identifies sex-specific SNPs associated with coronary microvascular dysfunction.

METHODS AND RESULTS

Six hundred and forty-three patients without significant obstructive coronary heart disease were enrolled, referred for cardiac catheterization, and underwent invasive coronary microcirculatory assessment. Patient data were collected from 1529 autosomal SNPs and seven X chromosome SNPs, which were selected to represent the variability from 76 candidate genes with published associations with coronary vasoreactivity, angiogenesis, inflammation, vascular calcification, atherosclerosis risk factors, female hormones, blood coagulation, or coronary heart disease. Coronary flow reserve (CFR) was assessed by an intracoronary injection of adenosine. Patients were categorized according to a CFR above or below 2.5 and were stratified by sex.After adjusting for age, sex, and BMI, this study shows that SNPs within VEGFA and CDKN2B-AS1 are associated with abnormal CFR (P<0.005). SNPs within MYH15, VEGFA, and NT5E are associated with abnormal CFR in men. No SNPs were associated with abnormal CFR in women.

CONCLUSION

Genetic variations within defined regions of VEGFA and CDKN2B-AS1 genes are associated with coronary microvascular dysfunction. Furthermore, sex-specific allelic variants within MYH15, VEGFA, and NT5E are associated with an increased risk of coronary microvascular dysfunction in men.

Sex-dependent association between coronary vessel dominance and cardiac syndrome X: a case-control study

BACKGROUND

Previous studies have demonstrated the relevance of left coronary artery dominance in the outcome and prognosis of obstructive coronary artery disease (CAD). However, no studies have investigated the influence of coronary vessel dominance on non obstructive CAD. The aim of this study was to establish the association of left and mixed dominance of the major epicardial arteries with the development of non obstructive CAD and evaluate potential sex-dependent differences in the coronary artery supply.

METHODS

A total of 484 patients underwent the same diagnostic procedures. The patients were divided into two groups based on their coronary angiogram results: the control group (242 patients with obstructive CAD; coronary artery stenosis of ≥50%) and the experimental group (242 patients with non obstructive CAD; coronary artery stenosis of <50%).

RESULTS

Significantly more women than men were affected by non obstructive CAD (P = 0.005). Left dominance was more frequent in the non obstructive CAD group than in the control group (P = 0.018) and was more pronounced in women than in men (P = 0.013). Among men with non obstructive CAD, a left supply was more frequent than a mixed supply (P = 0.012). Women with non obstructive CAD had a higher frequency of a left supply, whereas a mixed supply was less frequent in men than in patients with obstructive CAD (P = 0.013 and 0.018, respectively).

CONCLUSION

These results suggest that left dominance (particularly in women) and the absence of a mixed supply in men could cause regional ischemia, thus affecting the development of non obstructive CAD. Furthermore, sex may determine the incidence of specific coronary artery supply types, therefore influencing disease development and prognosis.

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.

Coronary microvascular dysfunction in women: an overview of diagnostic strategies

Coronary microvascular dysfunction (CMD) also known as syndrome X, is characterized by typical anginal symptoms, evidence of myocardial ischemia on non-invasive testing and normal to minimal coronary disease on coronary angiography. It has a female preponderance and has been detected in up to 50% of women presenting with chest pain symptoms. Definitive diagnosis of CMD is critical as recent evidence suggests that women with this condition are at increased risk of cardiovascular events in the future. Invasive coronary reactivity testing on coronary angiography is considered to be the 'gold standard' for diagnosis of CMD. Non-invasive imaging techniques such as PET and cardiac magnetic resonance hold promise for detection of CMD in the future.

Fractional flow reserve with dobutamine challenge and coronary microvascular endothelial dysfunction in symptomatic myocardial bridging

BACKGROUND

 Myocardial bridging (MB) results in compression of the coronary artery lumen in systole, extending into diastole with resultant hemodynamic alternation as reflected by fractional flow reserve (FFR). MB has also been associated with coronary endothelial dysfunction. The objective of this study was to investigate relationship between FFR with dobutamine challenge and coronary microvascular endothelial dysfunction in symptomatic MB.

METHODS AND RESULTS

 Seventeen consecutive patients who had cardiac catheterization assessment of MB were enrolled. The patients were divided into 2 groups according to normal (% increase in coronary blood flow [%CBF] ≥50%, n=7) or impaired (%CBF <50%, n=10) coronary microvascular endothelial function assessed on vasoreactivity in the coronary artery with intracoronary infusion of acetylcholine (Ach). Myocardial ischemia was then assessed using FFR at rest and during i.v. dobutamine infusion challenge across the MB with intracoronary pressure wires. FFR was significantly decreased at peak dobutamine infusion compared to at rest in the impaired group (0.85±0.06 vs. 0.91±0.05, P=0.001), but not in the normal group (0.93±0.05 vs. 0.91±0.07, P=0.618). Both FFR at rest and at peak dobutamine infusion had a positive correlation with %CBF by Ach in the impaired group (r(2)=0.46, P=0.030; r(2)=0.52, P=0.018, respectively).

CONCLUSIONS

 Microvascular endothelial dysfunction was associated with decreased FFR at peak dobutamine stress in patients with symptomatic MB. 

Multimodal SPION-CREKA peptide based agents for molecular imaging of microthrombus in a rat myocardial ischemia-reperfusion model

Microthrombosis plays a key role in many cardiovascular diseases. Although it is not difficult to localize thrombus within large or middle-sized vessels, the noninvasive diagnostic regimen for the detection of microthrombus remains scarce. Here we developed a nanoagent by conjucting superparamagnetic iron-oxide nanoparticle with fluorophore and a targeting element, CREKA, a peptide with special affinity for fibrin. In a rat model of myocardial ischemia-reperfusion (MI/R), the multimodal nanoagents were readily and selectively accumulated within microthrombosis, which was detectable by both magnetic resonance and optical imaging modalities. The fibrin-targeted nanoagent could be expected to have utility not only in molecular imaging of fibrin, understanding the mechanisms of microcirculation disorders, but also in targeted therapy with fibrinolytic agents.

The relationship between eosinophil and cardiac syndrome X

AIM

The pathophysiology of cardiac syndrome X (CSX) has not been clearly identified, although multiple abnormalities including microvascular spasm, endothelial dysfunction, and atherothrombosis have been reported. It is known that eosinophils play an important role in vasoconstruction and thrombosis. We aimed to compare the eosinophil counts in patients with CSX versus controls.

MATERIALS AND METHODS

This study included 50 patients with CSX (20 male, mean age 50.42 ± 9.6 years) and 30 control persons (10 male, mean age 49.16.11 ± 9.2 years). These participants underwent concurrent routine biochemical tests, and their eosinophil counts were obtained on whole blood count. These parameters were compared between groups.

RESULTS

Baseline characteristics of the study groups were comparable. Patients with CSX had a higher eosinophil count and mean platelet volume (MPV) value than the controls (339.4 ± 188 vs 132.7 ± 75 and 8.8 ± 0.2 vs 7.2 ± 0.1 fL; P < .001, respectively).

CONCLUSION

As a result, our study revealed a relationship between eosinophil count and MPV in patients with CSX.

Increased wave reflection and ejection duration in women with chest pain and nonobstructive coronary artery disease: ancillary study from the Women's Ischemia Syndrome Evaluation

OBJECTIVE

Wave reflections augment central aortic SBP and increase systolic pressure time integral (SPTI) thereby increasing left ventricular (LV) afterload and myocardial oxygen (MVO2) demand. When increased, such changes may contribute to myocardial ischemia and angina pectoris, especially when aortic diastolic time is decreased and myocardial perfusion pressure jeopardized. Accordingly, we examined pulse wave reflection characteristics and diastolic timing in a subgroup of women with chest pain (Women's Ischemia Syndrome Evaluation, WISE) and no obstructive coronary artery disease (CAD).

METHODS

Radial artery BP waveforms were recorded by applanation tonometry, and aortic BP waveforms derived. Data from WISE participants were compared with data from asymptomatic women (reference group) without chest pain matched for age, height, BMI, mean arterial BP, and heart rate.

RESULTS

Compared with the reference group, WISE participants had higher aortic SBP and pulse BP and ejection duration. These differences were associated with increased augmentation index and reflected pressure wave systolic duration. These modifications in wave reflection characteristics were associated with increased SPTI and wasted LV energy (Ew) and a decrease in pulse pressure amplification, myocardial viability ratio, and diastolic pressure time fraction.

CONCLUSION

WISE participants with no obstructive CAD have changes in systolic wave reflections and diastolic timing that increase LV afterload, MVO2 demand, and Ew with the potential to reduce coronary artery perfusion. These alterations in cardiovascular function contribute to an undesirable mismatch in the MVO2 supply/demand that promotes ischemia and chest pain and may contribute to, or increase the severity of, future adverse cardiovascular events.

The primary vascular dysregulation syndrome: implications for eye diseases

Vascular dysregulation refers to the regulation of blood flow that is not adapted to the needs of the respective tissue. We distinguish primary vascular dysregulation (PVD, formerly called vasospastic syndrome) and secondary vascular dysregulation (SVD). Subjects with PVD tend to have cold extremities, low blood pressure, reduced feeling of thirst, altered drug sensitivity, increased pain sensitivity, prolonged sleep onset time, altered gene expression in the lymphocytes, signs of oxidative stress, slightly increased endothelin-1 plasma level, low body mass index and often diffuse and fluctuating visual field defects. Coldness, emotional or mechanical stress and starving can provoke symptoms. Virtually all organs, particularly the eye, can be involved. In subjects with PVD, retinal vessels are stiffer and more irregular, and both neurovascular coupling and autoregulation capacity are reduced while retinal venous pressure is often increased. Subjects with PVD have increased risk for normal-tension glaucoma, optic nerve compartment syndrome, central serous choroidopathy, Susac syndrome, retinal artery and vein occlusions and anterior ischaemic neuropathy without atherosclerosis. Further characteristics are their weaker blood–brain and blood-retinal barriers and the higher prevalence of optic disc haemorrhages and activated astrocytes. Subjects with PVD tend to suffer more often from tinnitus, muscle cramps, migraine with aura and silent myocardial ischaemic and are at greater risk for altitude sickness. While the main cause of vascular dysregulation is vascular endotheliopathy, dysfunction of the autonomic nervous system is also involved. In contrast, SVD occurs in the context of other diseases such as multiple sclerosis, retrobulbar neuritis, rheumatoid arthritis, fibromyalgia and giant cell arteritis. Taking into consideration the high prevalence of PVD in the population and potentially linked pathologies, in the current article, the authors provide recommendations on how to effectively promote the field in order to create innovative diagnostic tools to predict the pathology and develop more efficient treatment approaches tailored to the person.

Microvascular coronary artery spasm presents distinctive clinical features with endothelial dysfunction as nonobstructive coronary artery disease

Background

Angina without significant stenosis, or nonobstructive coronary artery disease, attracts clinical attention. Microvascular coronary artery spasm (microvascular CAS) can cause nonobstructive coronary artery disease. We investigated the clinical features of microvascular CAS and the therapeutic efficacy of calcium channel blockers.

Methods and Results

Three hundred seventy consecutive, stable patients with suspected angina presenting nonobstructive coronary arteries (<50% diameter) in coronary angiography were investigated with the intracoronary acetylcholine provocation test, with simultaneous measurements of transcardiac lactate production and of changes in the quantitative coronary blood flow. We diagnosed microvascular CAS according to lactate production and a decrease in coronary blood flow without epicardial vasospasm during the acetylcholine provocation test. We prospectively followed up the patients with calcium channel blockers for microvascular coronary artery disease. We identified 50 patients with microvascular CAS who demonstrated significant impairment of the endothelium-dependent vascular response, which was assessed by coronary blood flow during the acetylcholine provocation test. Administration of isosorbide dinitrate normalized the abnormal coronary flow pattern in the patients with microvascular CAS. Multivariate logistic regression analysis indicated that female sex, a lower body mass index, minor–borderline ischemic electrocardiogram findings at rest, limited–baseline diastolic-to-systolic velocity ratio, and attenuated adenosine triphosphate–induced coronary flow reserve were independently correlated with the presence of microvascular CAS. Receiver-operating characteristics curve analysis revealed that the aforementioned 5-variable model showed good correlation with the presence of microvascular CAS (area under the curve: 0.820). No patients with microvascular CAS treated with calcium channel blockers developed cardiovascular events over 47.8±27.5 months.

Conclusions

Microvascular CAS causes distinctive clinical features and endothelial dysfunction that are important to recognize as nonobstructive coronary artery disease so that optimal care with calcium channel blockers can be provided.

Clinical Trial Registration

URL: www.umin.ac.jp/ctr. Unique identifier: UMIN000003839.

Therapy for stable angina in women

Mortality rates for cardiovascular disease are higher in women than in men, but studies of women have been conducted less frequently. Current pharmacological and nonpharmacological treatment options for women with stable angina are reviewed.