C-reactive protein, clinical presentation, and ischemic activity in patients with chest pain and normal coronary angiograms

The association between trimethylamine N-oxide levels and coronary microvascular dysfunction and prognosis in patients with ST-elevation myocardial infarction

BACKGROUND AND AIMS

Coronary microvascular dysfunction (CMD) is common after ST-elevation myocardial infarction (STEMI), leading to adverse clinical outcomes. However, its diagnosis remains difficult, and mechanisms elusive. This study explores the role of Trimethylamine N-oxide (TMAO), a gut microbiota metabolite, as a potential biomarker for diagnosing CMD in STEMI patients.

METHODS

This prospective, observational study enrolled 210 STEMI patients with multivessel coronary artery disease who underwent primary percutaneous coronary intervention (PCI). TMAO levels were measured at baseline, 3 months, and 12 months post-PCI, whilst coronary physiology was assessed at 3 months. The primary endpoint was the incidence of CMD at 3 months, with the secondary endpoint being major adverse cardiovascular and cerebrovascular events (MACCE) at 12 months. An additional 59 consecutive patients were enrolled for validation.

RESULTS

TMAO levels varied from baseline to 3 months, then stabilised. The areas under the ROC curve for baseline TMAO and TMAO at 3-month were 0.55 (95 % CI 0.46-0.64; p = 0.426), and 0.80 (95 % CI 0.73-0.87; p < 0.001), respectively. The optimal cut-off for TMAO at 3-month to diagnose CMD was 3.91, with similar sensitivity and specificity in the derivation and validation cohort. The incidence of MACCE was higher in patients with TMAO≥3.91 (41.4 % vs 10.7 %; p < 0.001). The addition of 3-month TMAO improved the diagnostic performance of traditional risk factors.

CONCLUSION

TMAO is a robust biomarker for CMD and is significantly associated with the incidence of MACCE. TMAO has the potential in guiding clinical decision-making and suggests an interplay between gut microbiota and CMD.

Pericardial fat volume is related to endothelial-mediated coronary blood flow in women with suspected coronary microvascular dysfunction. A report from the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD) study

Background

Coronary microvascular dysfunction is prevalent in women with signs and symptoms of ischemia but no obstructive coronary artery disease (CAD) and is associated with an adverse prognosis. Elevated pericardial fat volume predicts adverse cardiac events, but mechanistic pathways of the association are not well understood.

Methods

118 women enrolled in the NHLBI-sponsored Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction study with suspected coronary microvascular dysfunction but no obstructive CAD underwent adenosine stress 1.5 T cardiovascular magnetic resonance imaging (CMR) imaging and invasive coronary reactivity testing. Semi-quantitative myocardial perfusion reserve index (MPR) index was derived from perfusion images. Pericardial fat volume was measured by manually contouring the cardiac margins and adjacent adipose tissue on a single trans-axial HASTE slice at the level of the left main coronary artery origin and indexed to body surface-area. Simple standard deviation analysis obtained for continuous variables and frequency (percent) for categorical variables. The relationships between pericardial fat volume and coronary reactivity testing parameters were examined by correlation and multivariable regression analyses.

Results

Women with suspected coronary microvascular dysfunction had a mean age of 55 ± 10 years, body mass index (BMI) of 28 ± 7 kg/m2, 44 % had a history of smoking, 63 % hypertension, 8 % diabetes, and 20 % dyslipidemia. CMR imaging-derived pericardial fat volume and coronary blood flow response to intracoronary acetylcholine (Δ CBF) were negatively correlated (r = -0.32, p = 0.0013). After adjustment for age, number of risk factors, high-density lipoprotein (HDL), and cold pressor diameter response, pericardial fat volume remained a significant predictor of Δ coronary blood flow (p = 0.04). There was no association with other coronary reactivity testing measures or CMRI derived MPR index.

Conclusions

Among women with suspected coronary microvascular dysfunction but no obstructive CAD, pericardial fat volume appears to be related in a hypothesized adverse direction to coronary microvascular endothelial function. These results support further work confirming and extending these results to investigate pericardial fat volume as mechanistic pathway and potential treatment target for coronary microvascular dysfunction-related adverse events.Trial registration: clinicaltrials.govNCT00832702.

Long-Term Clinical Impact of Patients with Multi-Vessel Non-Obstructive Coronary Artery Disease

BACKGROUND

Non-obstructive coronary artery disease (CAD) is a disease commonly diagnosed in patients undergoing coronary angiography. However, little is known regarding the long-term clinical impact of multi-vessel non-obstructive CAD. Therefore, the object of this study was to investigate the long-term clinical impact of multi-vessel non-obstructive CAD.

METHOD

A total of 2083 patients without revascularization history and obstructive CAD were enrolled between January 2010 and December 2015. They were classified into four groups according to number of vessels involved in non-obstructive CAD (25% ≤ luminal stenosis < 70%): zero, one, two, or three diseased vessels (DVs). We monitored the patients for 5 years. The primary outcome was major cardiovascular and cerebrovascular events (MACCEs), defined as a composite of cardiac death, stroke, and myocardial infarction (MI).

RESULT

The occurrence of MACCEs increased as the number of non-obstructive DVs increased, and was especially high in patients with three DVs. After adjustment, patients with three DVs still showed significantly poorer clinical outcomes of MACCEs, stroke, and MI compared those with zero DVs.

CONCLUSION

Multi-vessel non-obstructive CAD, especially in patients with non-obstructive three DVs, is strongly associated with poor long-term clinical outcomes. This finding suggests that more intensive treatment may be required in this subset of patients.

Coronary Microvascular Dysfunction: What Clinicians and Investigators Should Know

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Circulating Biomarkers in Coronary Microvascular Dysfunction

Coronary microvascular dysfunction is an underdiagnosed pathologic process that is associated with adverse clinical outcomes. Biomarkers, molecules measurable in the blood, could inform the clinician by aiding in the diagnosis and management of coronary microvascular dysfunction. We present an updated review of circulating biomarkers in coronary microvascular dysfunction representing key pathologic processes, including inflammation, endothelial dysfunction, oxidative stress, coagulation, and other mechanisms.

Myocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA): Focus on Coronary Microvascular Dysfunction and Genetic Susceptibility

Among the most common causes of death worldwide, ischemic heart disease (IHD) is recognized to rank first. Even if atherosclerotic disease of the epicardial arteries is known as the leading cause of IHD, the presence of myocardial infarction with non-obstructive coronary artery disease (MINOCA) is increasingly recognized. Notwithstanding the increasing interest, MINOCA remains a puzzling clinical entity that can be classified by distinguishing different underlying mechanisms, which can be divided into atherosclerotic and non-atherosclerotic. In particular, coronary microvascular dysfunction (CMD), classifiable in non-atherosclerotic mechanisms, is a leading factor for the pathophysiology and prognosis of patients with MINOCA. Genetic susceptibility may have a role in primum movens in CMD. However, few results have been obtained for understanding the genetic mechanisms underlying CMD. Future studies are essential in order to find a deeper understanding of the role of multiple genetic variants in the genesis of microcirculation dysfunction. Progress in research would allow early identification of high-risk patients and the development of pharmacological, patient-tailored strategies. The aim of this review is to revise the pathophysiology and underlying mechanisms of MINOCA, focusing on CMD and actual knowledge about genetic predisposition to it.

Updates on Pharmacologic Management of Microvascular Angina

Microvascular angina (MVA), historically called cardiac syndrome X, refers to angina with nonobstructive coronary artery disease. This female-predominant cardiovascular disorder adds considerable health-related costs due to repeated diagnostic angiography and frequent hospital admissions. Despite the high prevalence of this diagnosis in patients undergoing coronary angiography, it is still a therapeutic challenge for cardiologists. Unlike obstructive coronary artery disease, with multiple evidence-based therapies and management guidelines, little is known regarding the management of MVA. During the last decade, many therapeutic interventions have been suggested for the treatment of MVA. However, there is a lack of summarization tab and update of current knowledge about pharmacologic management of MVA, mostly due to unclear pathophysiology. In this article, we have reviewed the underlying mechanisms of MVA and the outcomes of various medications in patients with this disease. Contrary to vasospastic angina in which normal angiogram is observed as well, nitrates are not effective in the treatment of MVA. Beta-blockers and calcium channel blockers have the strongest evidence of improving the symptoms. Moreover, the use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, statins, estrogen, and novel antianginal drugs has had promising outcomes. Investigations are still ongoing for vitamin D, omega-3, incretins, and n-acetyl cysteine, which have resulted in beneficial initial outcomes. We believe that the employment of the available results and results of the future large-scale trials into cardiac care guidelines would help reduce the global cost of cardiac care tremendously.

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

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

Advances and Challenges in Biomarkers Use for Coronary Microvascular Dysfunction: From Bench to Clinical Practice

Coronary microvascular dysfunction (CMD) is related to a broad variety of clinical scenarios in which cardiac microvasculature is morphologically and functionally affected, and it is associated with impaired responses to vasoactive stimuli. Although the prevalence of CMD involves about half of all patients with chronic coronary syndromes and more than 20% of those with acute coronary syndrome, the diagnosis of CMD is often missed, leading to the underestimation of its clinical importance. The established and validated techniques for the measurement of coronary microvascular function are invasive and expensive. An ideal method to assess endothelial dysfunction should be accurate, non-invasive, cost-effective and accessible. There are varieties of biomarkers available, potentially involved in microvascular disease, but none have been extensively validated in this heterogeneous clinical population. The investigation of potential biomarkers linked to microvascular dysfunction might improve the assessment of the diagnosis, risk stratification, disease progression and therapy response. This review article offers an update about traditional and novel potential biomarkers linked to CMD.

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

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

Biomarkers of Coronary Microvascular Dysfunction in Patients With Microvascular Angina: A Narrative Review

The current gold standard for diagnosis of coronary microvascular dysfunction (CMD) in the absence of myocardial diseases, whose clinical manifestation is microvascular angina (MVA), is reactivity testing using adenosine or acetylcholine during coronary angiography. This invasive test can be difficult to perform, expensive, and harmful. The identification of easily obtainable blood biomarkers which reflect the pathophysiology of CMD, characterized by high reliability, precision, accuracy, and accessibility may reduce risks and costs related to invasive procedures and even facilitate the screening and diagnosis of CMD. In this review, we summarized the results of several studies that have investigated the possible relationships between blood biomarkers involved with CMD and MVA. More specifically, we have divided the analyzed biomarkers into 3 different groups, according to the main mechanisms underlying CMD: biomarkers of "endothelial dysfunction," "vascular inflammation," and "oxidative stress." Finally, in the last section of the review, we consider mixed mechanisms and biomarkers which are not included in the 3 major categories mentioned above, but could be involved in the pathogenesis of CMD.

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

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

Is microvascular dysfunction a systemic disorder with common biomarkers found in the heart, brain, and kidneys? - A scoping review

Although microvascular dysfunction (MVD) has been well characterized in individual organs as different disease entities, clinical evidence is mounting in support of an underlying systemic process. To address this hypothesis, we systematically searched PubMed and Medline for studies in adults published between 2014 and 2019 that measured blood biomarkers of MVD in three vital organs i.e. brain, heart, and the kidney. Of the 9706 unique articles 321 met the criteria, reporting 49 biomarkers of which 16 were common to the three organs. Endothelial dysfunction, inflammation including reactive oxidation, immune activation, and coagulation were the commonly recognized pathways. Triglyceride, C-reactive protein, Cystatin C, homocysteine, uric acid, IL-6, NT-proBNP, thrombomodulin, von Willebrand Factor, and uric acid were increased in MVD of all three organs. In contrast, vitamin D was decreased. Adiponectin, asymmetric dimethylarginine, total cholesterol, high-density and low-density cholesterol were found to be variably increased or decreased in studies. We review the pathways underlying MVD in the three organs and summarize evidence supporting its systemic nature. This scoping review informs clinicians and researchers in the multi-system manifestation of MVD. Future work should focus on longitudinal investigations to evaluate the multi-system involvement of this disease.

Sex differences in non-obstructive coronary artery disease

Ischaemic heart disease is a leading cause of morbidity and mortality in both women and men. Compared with men, symptomatic women who are suspected of having myocardial ischaemia are more likely to have no obstructive coronary artery disease (CAD) on coronary angiography. Coronary vasomotor disorders and coronary microvascular dysfunction (CMD) have been increasingly recognized as important contributors to angina and adverse outcomes in patients with no obstructive CAD. CMD from functional and structural abnormalities in the microvasculature is associated with adverse cardiac events and mortality in both sexes. Women may be particularly susceptible to vasomotor disorders and CMD due to unique factors such as inflammation, mental stress, autonomic, and neuroendocrine dysfunction, which predispose to endothelial dysfunction and CMD. CMD can be detected with coronary reactivity testing and non-invasive imaging modalities; however, it remains underdiagnosed. This review focuses on sex differences in presentation, pathophysiologic risk factors, diagnostic testing, and prognosis of CMD.

Ischaemia with no obstructive coronary arteries

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

Triglyceride to high-density lipoprotein cholesterol ratio as a predictor of long-term mortality in patients with coronary artery disease after undergoing percutaneous coronary intervention: a retrospective cohort study

BACKGROUND

It has been confirmed that the triglyceride to high-density lipoprotein cholesterol ratio (THR) is associated with insulin resistance and metabolic syndrome. However, to the best of our knowledge, only a few studies with small sample sizes have investigated the relationship between THR and coronary artery disease (CAD). Therefore, we aimed to assess the correlation between the THR and long-term mortality in patients with CAD after undergoing percutaneous coronary intervention (PCI) in our study that enrolled a large number of patients.

METHODS

A total of 3269 post-PCI patients with CAD were enrolled in the CORFCHD-ZZ study from January 2013 to December 2017. The mean follow-up time was 37.59 ± 22.24 months. Patients were divided into two groups according to their THR value: the lower group (THR < 2.84, n = 1232) and the higher group (THR ≥ 2.84, n = 2037). The primary endpoint was long-term mortality, including all-cause mortality (ACM) and cardiac mortality (CM). The secondary endpoints were major adverse cardiac events (MACEs) and major adverse cardiac and cerebrovascular events (MACCEs).

RESULTS

In our study, ACM occurred in 124 patients: 30 (2.4%) in the lower group and 94 (4.6%) in the higher group (P = 0.002). MACEs occurred in 362 patients: 111 (9.0%) in the lower group and 251 (12.3%) in the higher group (P = 0.003). The number of MACCEs was 482: 152 (12.3%) in the lower group and 320 (15.7%) in the higher group (P = 0.008). Heart failure occurred in 514 patients: 89 (7.2%) in the lower group and 425 (20.9%) in the higher group (P < 0.001). Kaplan-Meier analyses showed that elevated THR was significantly related to long-term ACM (log-rank, P = 0.044) and the occurrence of heart failure (log-rank, P < 0.001). Multivariate Cox regression analyses showed that the THR was an independent predictor of long-term ACM (adjusted HR = 2.042 [1.264-3.300], P = 0.004) and heart failure (adjusted HR = 1.700 [1.347-2.147], P < 0.001).

CONCLUSIONS

An increased THR is an independent predictor of long-term ACM and heart failure in post-PCI patients with CAD.

Receptor for advanced glycation end products gene polymorphisms in cardiac syndrome X

Endothelial and microvascular dysfunction serve important roles in the formation and pathogenesis of cardiac syndrome X (CSX). Expression of receptor for advanced glycation end products (RAGE) is suggested to be increased in several conditions, including diabetes, inflammation and vascular diseases. In the present study, RAGE gene polymorphisms in patients with CSX and healthy controls were investigated. A total of 114 patients, diagnosed with CSX using coronary angiography results following complaints of angina and objective ischemia, and 103 healthy controls participated in the study. Whether there was a difference in genotype distributions of RAGE gene -374T/A, -429T/C and Glys82Ser polymorphisms between patients with CSX and healthy controls was investigated. Following DNA isolation from blood samples of the participants, the polymorphic regions were examined by quantitative polymerase chain reaction, and the genotyping results were statistically analyzed. When the genotypic distributions of -374T/A, -429T/C and Gly82Ser polymorphisms were investigated in patients with CSX and healthy controls, no statistically significant differences were identified between the two groups (P>0.05). Likewise, no statistically significant differences were observed in the allelic distributions of all 3 polymorphic regions (P>0.05). To the best of our knowledge, the present study also investigated the association between CSX and RAGE gene polymorphisms for the first time. No statistically significant differences in RAGE gene polymorphisms between the CSX and control groups were observed. We hypothesized that significant results may be obtained by increasing the numbers of patients and healthy controls in future studies.

Association of Inflammation and Endothelial Dysfunction with Coronary Microvascular Resistance in Patients with Cardiac Syndrome X

Background

Although a proportion of CSX patients have impaired brachial artery flow-mediated dilatation (FMD) in response to hyperemia, suggesting that endothelial dysfunction in these patients may be systemic and not just confined to the coronary circulation; the underlying mechanisms triggering endothelial dysfunction in these patients are still incompletely understood.

Objectives

To assess the association of the index of Microcirculatory Resistance (IMR) with endothelial dysfunction and inflammation in patients with CSX.

Methods

We studied 20 CSX patients and 20 age and gender-matched control subjects. Thermodilution-derived coronary flow reserve (CFR) and IMR were measured using a pressure-temperature sensor-tipped guidewire. Brachial artery FMD was measured using high-resolution, two-dimensional ultrasound images obtained with a Doppler ultrasound device (HDI-ATL 5000, USA) with a 5 MHz to 12 MHz linear-array transducer.

Results

Compared with in control subjects, CFR was significantly lower (2.42 ± 0.78 vs. 3.59 ± 0.79, p < 0.001); IMR was higher (32.2 ± 8.0 vs. 19.5 ± 5.5, p < 0.001); the concentration of hs-CRP and FMD was higher (4.75 ± 1.62 vs. 2.75 ± 1.50; 5.24 ± 2.41 vs. 8.57 ± 2.46, p < 0.001) in CSX patients. The Duke treadmill score (DTS) was correlated positively to CFR and FMD (0.489 and 0.661, p < 0.001), it was negative to IMR and hsCRP (-0.761 and -0.087, p < 0.001) in CSX patients.

Conclusions

The main finding in this study is that the DTS measured in patients with CSX was associated to hsCRP and FMD. Moreover, the independent effects of exercise tolerance can significantly impair FMD and hsCRP in CSX patients; especially it is particularly important to whom where FMD was associated negatively with IMR.

Inflammatory biomarkers as predictors of heart failure in women without obstructive coronary artery disease: A report from the NHLBI-sponsored Women's Ischemia Syndrome Evaluation (WISE)

Background

Women with signs and symptoms of ischemia, no obstructive coronary artery disease (CAD) and preserved left ventricular ejection fraction (EF) often have diastolic dysfunction and experience elevated rates of major adverse cardiac events (MACE), including heart failure (HF) hospitalization with preserved ejection fraction (HFpEF). We evaluated the predictive value of inflammatory biomarkers for long-term HF hospitalization and all-cause mortality in these women.

Methods

We performed a cross-sectional analysis to investigate the relationships between inflammatory biomarkers [serum interleukin-6 (IL-6), C-reactive protein (hs-CRP) and serum amyloid A (SAA)] and median of 6 years follow-up for all-cause mortality and HF hospitalization among women with signs and symptoms of ischemia, non-obstructive CAD and preserved EF. Multivariable Cox regression analysis tested associations between biomarker levels and adverse outcomes.

Results

Among 390 women, mean age 56 ± 11 years, median follow up of 6 years, we observed that there is continuous association between IL-6 level and HF hospitalization (adjusted hazard ratio [AHR] 2.5 [1.2–5.0], p = 0.02). In addition, we found significant association between IL-6, SAA levels and all-cause mortality AHR (1.8 [1.1–3.0], p = 0.01) (1.5 [1.0–2.1], p = 0.04), respectively.

Conclusion

In women with signs and symptoms of ischemia, non-obstructive CAD and preserved EF, elevated IL-6 predicted HF hospitalization and all-cause mortality, while SAA level was only associated with all-cause mortality. These results suggest that inflammation plays a role in the pathogenesis of development of HFpEF, as well all-cause mortality.

Investigation of MTHFR gene C677T polymorphism in cardiac syndrome X patients

BACKGROUND

Definition of Cardiac Syndrome X (CSX) refers to groups of patients with positive exercise stress test and normal epicardial coronary arteries on coronary angiography accompanied by chest pain. Although the etiology of CSX is not completely understood, there is a common consensus that its pathophysiology may be associated with endothelial dysfunction resulting in impaired coronary flow. Some polymorphisms observed on the MTHFR gene cause inactivation of the MTHFR enzyme, leading to hyperhomocysteinemia and homocysteinuria, which are prominent risk factors of cardiovascular and cerebrovascular diseases. It was aimed to explain the association of the endothelial dysfunction, which is thought to play a role in the pathophysiology of CSX, with C677T polymorphism on MTHFR gene based on genetic basis.

METHODS

A total of 176 CSX patients and 196 healthy subjects with similar age and clinical features were compared in terms of C677T polymorphism of the MTHFR gene.

RESULTS AND CONCLUSION

There was no significant difference in terms of MTHFR gene C677T polymorphism between CSX patients and controls. When genotypic distribution was compared based on gender in both patients and controls, no significant difference was found between male and female subjects (P>.05). As fasting blood sugar and urea values were significantly higher, alanine aminotransferase and gamma-glutamyl transferase levels were significantly lower in the patients than the controls (P<.05). Described family story of the patients was significantly higher than the controls (P<.05). These suggest that homocysteine metabolism in CSX is not directly related to the endothelial dysfunction and thus the effect on the microvascular circulation.

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

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

Women with Stable Angina Pectoris and No Obstructive Coronary Artery Disease: Closer to a Diagnosis

A large proportion of women with chest pain have no obstructive coronary artery disease. Recent studies have demonstrated that these women continue to have symptoms and are at increased risk of cardiovascular morbidity and mortality. Coronary microvascular dysfunction (CMD) leads to an impairment of blood flow regulation to the myocardium and possible transient ischaemia. CMD is a disease entity with several pathophysiologic aspects and diagnostic modalities continue to be developed. However, due to the complexity of the disease, it remains elusive whether CMD is the explanation for the symptoms and the poor prognosis in women with angina and no obstructive coronary artery disease.

Association of endothelial dysfunction and cytotoxin-associated gene A-positive Helicobacter pylori in patients with cardiac syndrome X

Background

Existence of coronary endothelial dysfunction has been demonstrated in patients with cardiac syndrome X (CSX). In addition, Helicobacter pylorus (H. pylori) has been associated with CSX. We aimed to assess the possible association of endothelial dysfunction and cytotoxin-associated gene A-positive H. pylori (CagA+) infection in CSX patients.

Methods

Fifty-six patients with CSX (23 male/33 female; age: 51.25 ± 8.86 years) who were anti-H. pylori IgG-positive [H. pylori(+)] and 24 CSX patients (7 male/17 female; age: 52.79 ± 9.88 years) who were H. pylori(−) were included. Also, anti-H. pylori IgG-positive patients were determined by the presence of IgG antibody to CagA. Levels of endothelin-1 (ET-1), E-selectin and intercellular adhesion molecule-1 (ICAM-1) were measured.

Results

Endothelial dysfunction biomarkers were higher in H. pylori(+) than in H. pylori(−) patients (ET-1: 54.60 ± 25.39 vs. 42.59 ± 18.37 pg/ml, p = 0.04; E-selectin: 42.68 ± 14.26 vs. 31.72 ± 8.26 ng/ml, p = 0.001; ICAM-1: 339.68 ± 135.8 vs. 266.51 ± 125.1 ng/ml, p = 0.02). Among H. pylori(+) subjects, 28 cases were CagA(+) and 28 cases were CagA(−). There were significant differences in measured levels of E-selectin between CagA(+) and CagA(−) groups (48.00 ± 16.37 vs. 37.37 ± 9.37 ng/ml, p = 0.004). For ET-1 and ICAM-1 levels, the difference between CagA(+) and CagA(−) was insignificant (p = 0.174 and p = 0.07, respectively).

Conclusion

High levels of endothelial dysfunction biomarkers are found in CSX patients with anti-CagA(+). These findings suggest the infection with CagA(+) H. pylori strain may play a role as a risk factor in development of CSX through provocation of endothelial dysfunction. Therefore, a long term follow up to investigate the outcomes of these patients is proposed.

Human Endothelial Cell-Specific Molecule-1 (Endocan) and Coronary Artery Disease and Microvascular Angina

Endothelial cell-specific molecule-1 (endocan) is an immunoinflammatory marker linked to endothelial activation and dysfunction. We investigated the relationship between obstructive coronary artery disease (CAD), microvascular angina (MVA), and plasma levels of endocan. We included 53 healthy individuals as controls, 40 MVA patients, and 120 patients with obstructive CAD. The severity of CAD was assessed by the Gensini and SYNergy between percutaneous coronary intervention with TAXUS and Cardiac Surgery (SYNTAX) scores. Endocan levels were 382.7 (313.8-470.2) pg/mL in patients with obstructive CAD; 324.3 (277.1-460.7) pg/mL in MVA group, and 268.0 (226.4-336.5) pg/mL ( P < .001) in controls. Endocan levels in obstructive CAD and MVA groups were similar but both were significantly higher than for the control group ( P < .001 and P = .002, respectively). In subgroup analysis, similar to the hypertensive subgroup results, endocan was still an independent predictor of presence of obstructive CAD in normotensives (odds ratio = 1.005, 95% confidence interval = 1.001-1.010, P = .024). There was also an independent positive correlation between endocan levels and SYNTAX score both in the hypertensives (β = 0.414, t = 3.21, P = .002) and in the normotensives (β = .301, t = 2.23, P = .031). In conclusion, endocan could be a common predictor of the endothelium-dependent inflammatory processes, rather than related with specific risk factors.

Stress cardiomyopathy: Is it limited to Takotsubo syndrome? Problems of definition

In 2006, Takotsubo syndrome (TTC) was described as a distinct type of stress-induced cardiomyopathy (stress cardiomyopathy). However, when thinking about Takotsubo cardiomyopathy from the viewpoints of the AHA and ESC classifications, 2 possible problems may arise. The first potential problem is that a forecast of disease outcome is lacking in the ESC classification, whereas the AHA only states that 'outcome is favorable with appropriate medical therapy'. However, based on the literature data, one can make a general conclusion that occurrence of myocardial lesions in TTC (i.e., myocardial fibrosis and contraction-band necrosis) causes the same effects as in other diseases with similar levels of myocardial damage and should not be considered to have a lesser impact on mortality. To summarise, TTC can cause not only severe complications such as pulmonary oedema, cardiogenic shock, and dangerous ventricular arrhythmias, but also damage to the myocardium, which can result in the development of potentially fatal conditions even after the disappearance of LV apical ballooning. The second potential problem arises from the definition of TTC as a stress cardiomyopathy in the AHA classification. In fact, the main factors leading to TTC are stress and microvascular anginas, since, as has been already discussed, coronary spasm can cause myocardium stunning, resulting in persistent apical ballooning. Thus, based on this review, 3 distinct types of stress cardiomyopathies exist (variant angina, microvascular angina, and TTC), with poor prognosis. Adding these diseases to the classification of cardiomyopathies will facilitate diagnosis and preventive prolonged treatment, which should include intensive anti-stress therapy.

Novel biomarkers of coronary microvascular disease

Coronary microvascular disease in the absence of myocardial diseases has traditionally been diagnosed through coronary reactivity testing in the cardiac catheterization laboratory. Compared with invasive procedures, blood-based biomarkers may have reduced cost, less risk of physical harm and greater accessibility, making them ideal for an outpatient management strategy. There are a variety of biomarkers available with potential utility in the management of microvascular disease; however, none have yet been extensively validated or established in this clinical patient population.

Strategies and methods to study female-specific cardiovascular health and disease: a guide for clinical scientists

BACKGROUND

In 2001, the Institute of Medicine's (IOM) report, "Exploring the Biological Contributions to Human Health: Does Sex Matter?" advocated for better understanding of the differences in human diseases between the sexes, with translation of these differences into clinical practice. Sex differences are well documented in the prevalence of cardiovascular (CV) risk factors, the clinical manifestation and incidence of cardiovascular disease (CVD), and the impact of risk factors on outcomes. There are also physiologic and psychosocial factors unique to women that may affect CVD risk, such as issues related to reproduction.

METHODS

The Society for Women's Health Research (SWHR) CV Network compiled an inventory of sex-specific strategies and methods for the study of women and CV health and disease across the lifespan. References for methods and strategy details are provided to gather and evaluate this information. Some items comprise robust measures; others are in development.

RESULTS

To address female-specific CV health and disease in population, physiology, and clinical trial research, data should be collected on reproductive history, psychosocial variables, and other factors that disproportionately affect CVD in women. Variables related to reproductive health include the following: age of menarche, menstrual cycle regularity, hormone levels, oral contraceptive use, pregnancy history/complications, polycystic ovary syndrome (PCOS) components, menopause age, and use and type of menopausal hormone therapy. Other factors that differentially affect women's CV risk include diabetes mellitus, autoimmune inflammatory disease, and autonomic vasomotor control. Sex differences in aging as well as psychosocial variables such as depression and stress should also be considered. Women are frequently not included/enrolled in mixed-sex CVD studies; when they are included, information on these variables is generally not collected. These omissions limit the ability to determine the role of sex-specific contributors to CV health and disease. Lack of sex-specific knowledge contributes to the CVD health disparities that women face.

CONCLUSIONS

The purpose of this review is to encourage investigators to consider ways to increase the usefulness of physiological and psychosocial data obtained from clinical populations, in an effort to improve the understanding of sex differences in clinical CVD research and health-care delivery for women and men.

Coronary endothelial dysfunction in non-obstructive coronary artery disease: Risk, pathogenesis, diagnosis and therapy

Up to half of patients with signs and symptoms of stable ischemic heart disease have non-obstructive coronary artery disease (NoCAD). Recent evidence demonstrates that two-thirds of patients with NoCAD have demonstrable coronary endothelial dysfunction represented by microvascular or diffuse epicardial spasm following acetylcholine challenge. Patients with coronary endothelial dysfunction are recognized to have significant health services use and morbidity as well as increased risk of developing flow-limiting coronary artery disease and myocardial events, including death. Currently, there are few centers that test for this etiology owing to lack of knowledge, limited evidence for treatment options and invasive diagnostic strategies. This article reviews the pathophysiology, epidemiology, diagnosis and treatment of coronary endothelial dysfunction as a subgroup of NoCAD.

Chronic Inflammatory Disease Is an Independent Risk Factor for Coronary Flow Velocity Reserve Impairment Unrelated to the Processes of Coronary Artery Calcium Deposition

BACKGROUND

Chronic inflammatory disease (CID) is a complex multisystem disease characterized by chronic inflammation, which can lead to coronary microvascular dysfunction (CMD) and can also predispose to coronary artery calcium deposition, even in the absence of obstructive coronary artery disease.

METHODS

Twenty-one patients with systemic lupus erythematosus (SLE; mean age, 60 ± 11 years), 21 patients with systemic sclerosis (SSc; mean age, 66 ± 11 years), 32 patients with rheumatoid arthritis (RA; mean age, 65 ± 9 years), and 23 control subjects with comparable traditional risk factors for coronary artery disease (mean age, 65 ± 10 years) were prospectively enrolled in the outpatient clinic. All study participants underwent transthoracic Doppler-derived echocardiography for coronary flow velocity reserve (CFVR) measurement in the left anterior descending coronary artery; CFVR < 2.5 defined CMD. Coronary artery calcium score in the left anterior descending coronary artery was also assessed by computed tomography.

RESULTS

None of study participants had obstructive coronary artery disease. The prevalence of CMD was 26% in the control group, 67% in the SLE group, 76% in the SSc group, and 63% in the RA group (P < .05, CID groups vs control group). CFVR was significantly lower in all three CID groups than in the control group (control group, 3.01 ± 0.72; SLE group, 2.23 ± 0.71; SSc group, 2.14 ± 0.54; RA group, 2.33 ± 0.62; P < .05, CID groups vs control group). In contrast, coronary artery calcium scores were similar in the four groups and had no relation to CMD. The odds ratios for CMD in patients with SLE, SSc, and RA were 16.70, 25.78, and 8.44 (P < .05) after adjusting for age, body mass index, the presence or absence of anemia, and hemoglobin level. Multiple linear regression analysis showed that only the presence of CID was independently associated with reduced CFVR among all study participants.

CONCLUSIONS

CID strongly contributes to CMD identified by qualitative evaluation of CFVR independently of traditional coronary risk factors of atherosclerosis but does not predispose to coronary artery calcification.

Coronary Flow Velocity Reserve in Burn Injury: A Prospective Clinical Cohort Study

The authors sought to evaluate coronary microvascular function and left ventricular diastolic dysfunction using transthoracic Doppler echocardiography in burn patients. In this study, 32 adult burn patients with partial or full-thickness scald burns that were hospitalized and treated were included. The control group was matched for age and sex and was composed of otherwise healthy volunteers. Transthoracic Doppler echocardiography examinations and simultaneous laboratory tests for cardiac evaluation were performed on the sixth month after burn injury as well as with the control group. High-sensitivity C-reactive protein levels were significantly higher in the burn patients than in controls (5.17 ± 3.86 vs 2.42 ± 1.78; P = .001). Lateral isovolumic relaxation time was significantly higher in the burn injury group than in the control group (92.7 ± 15.7 vs 85.5 ± 8.3; P = .03). Baseline coronary diastolic peak flow velocity of the left anterior descending artery was similar in both groups. However, hyperemic diastolic peak flow velocity and coronary flow velocity reserve (2.26 ± 0.48 vs 2.94 ± 0.47; P < .001) were significantly lower in the burn injury group than in the control group. Coronary flow velocity reserve was significantly and inversely correlated with high-sensitivity C-reactive protein, burn ratio, creatinine, and mitral A-wave max velocity. At the sixth month of treatment, burn patients had high-sensitivity C-reactive protein levels during this period, suggesting that inflammation still exists. In addition, subclinical coronary microvascular and left ventricular diastolic dysfunction can occur in burn patients without traditional cardiovascular risk factors. However, these results must be supported by additional studies.

Does Inflammation Have a Role in the Pathogenesis of Cardiac Syndrome X? A Genetic-Based Clinical Study With Assessment of Multiple Cytokine Levels

We compared Turkish patients with cardiac syndrome X (CSX) and controls with respect to serum pro- and anti-inflammatory cytokine levels, as well as the single-nucleotide polymorphisms located in the promoter regions of their related genes. This study included 111 consecutive patients angiographically diagnosed with CSX and 111 healthy controls with similar demographic characteristics. Serum interleukin (IL) 6, tumor necrosis factor α (TNF-α), and IL-10 levels were measured, and the genotypes of the patients and controls were determined using standard methods. Serum IL-6 and IL-10 levels were significantly higher in the CSX group than in the control group ( P < .01, respectively). Serum TNF-α level was lower in the CSX group than in the control group ( P < .001). On the other hand, participants with CSX and healthy controls were not significantly different with respect to the genotype distributions of IL-6, TNF-α, and IL-10 genes. As a result of our study, both pro-inflammatory and anti-inflammatory cytokines may play a role in the pathogenesis of CSX. In contrast, the studied gene polymorphisms did not influence CSX pathogenesis.

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.

A prospective study of C-reactive protein as a state marker in Cardiac Syndrome X

Cardiac Syndrome X (CSX), the presence of angina pectoris despite normal epicardial coronary arteries seen on invasive angiography, is known to be associated with an elevation of several inflammatory biomarkers, suggesting a possible role for inflammation in its pathogenesis. We sought to establish if C-reactive protein (CRP) levels varied with disease severity and so whether it is a state or trait marker. We studied 16 CSX patients with typical angina pectoris, normal coronary arteries and an electrically positive exercise stress test (EST) and 13 age- and sex-matched healthy controls (HC). CSX patients were followed up at a subsequent visit with repeated exercise stress testing and CRP measurement. We found that CRP levels were significantly higher in the CSX group compared to the HC (1.5 [0.8-4.5] v 0.8 [0.4-1.4] mg/L, p=0.02). This elevation in CRP persisted throughout the study length. CRP correlated with time to symptoms on EST at enrolment and at the second visit (r=-0.690, df=10, p=0.013 and r=-0.899, df=4, p=0.015, respectively). At the follow-up visit, 50% of CSX patients developed electrically and symptomatically negative ESTs. The mean CRP of this group was significantly lower than that of the CSX patients with ongoing symptoms and positive ESTs (1.2±0.2 v 2.8±0.6mg/L, p=0.018) and did not differ significantly from that of healthy controls. CRP levels also dropped in patients whose symptoms improved while they increased in patients who became more symptomatic (p=0.027). We conclude that the results of this small study support the concept of CSX being an inflammatory-mediated condition with CRP levels prospectively varying with functional measures of disease severity. This indicates that CRP is a state marker in CSX.

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.

Nitric oxide synthetic pathway in patients with microvascular angina and its relations with oxidative stress

A decreased nitric oxide (NO) bioavailability and an increased oxidative stress play a pivotal role in different cardiovascular pathologies. As red blood cells (RBCs) participate in NO formation in the bloodstream, the aim of this study was to outline the metabolic profile of L-arginine (Arg)/NO pathway and of oxidative stress status in RBCs and in plasma of patients with microvascular angina (MVA), investigating similarities and differences with respect to coronary artery disease (CAD) patients or healthy controls (Ctrl). Analytes involved in Arg/NO pathway and the ratio of oxidized and reduced forms of glutathione were measured by LC-MS/MS. The arginase and the NO synthase (NOS) expression were evaluated by immunofluorescence staining. RBCs from MVA patients show increased levels of NO synthesis inhibitors, parallel to that found in plasma, and a reduction of NO synthase expression. When summary scores were computed, both patient groups were associated with a positive oxidative score and a negative NO score, with the CAD group located in a more extreme position with respect to Ctrl. This finding points out to an impairment of the capacity of RBCs to produce NO in a pathological condition characterized mostly by alterations at the microvascular bed with no significant coronary stenosis.

High-sensitivity C-reactive protein and exercise-induced changes in subjects suspected of coronary artery disease

BACKGROUND

Inflammation plays a major role in the development of atherosclerosis. We wanted to investigate the effects of exercise on high-sensitivity (hs) C-reactive protein (CRP) in subjects who were suspected of having coronary artery disease (CAD).

METHODS

Blood samples were obtained before, 5 minutes after, and 20 hours after an exercise test in 155 subjects who were suspected of CAD. Coronary anatomy was evaluated by computed tomography coronary angiography and/or coronary angiography.

RESULTS

Median baseline hs-CRP was higher in subjects with ≥50% coronary artery lumen diameter stenosis (n=41), compared with non-CAD-subjects (n=114), 2.93 mg/L (interquartile range 1.03-5.06 mg/L) and 1.30 mg/L (interquartile range 0.76-2.74 mg/L), respectively, P=0.007. In multivariate analyses testing conventional risk factors, hs-CRP proved borderline significant, odds ratio =2.32, P=0.065. Adding baseline hs-CRP to the results of the exercise test did not improve the diagnostic evaluation. Baseline natural logarithm (Ln) hs-CRP was positively associated with body mass index and baseline Ln-transformed hs troponin T levels, and negatively associated with the daily life activity level. An increase in hs-CRP of 0.13 mg/L (interquartile range 0.05-0.24 mg/L) from baseline to 5 minutes after peak exercise was found (P<0.0001), but the increase was not associated with presence of CAD. From baseline to 20 hours after exercise, no increase in hs-CRP was found.

CONCLUSION

In conclusion, hs-CRP was not independently associated with CAD. Hs-CRP increased immediately as a response to the exercise, and the increase was modest and not associated with CAD. The results indicate that exercise has potential to cause unwanted variations in hs-CRP and that exercise prior to hs-CRP measurements in subjects included in epidemiological studies, therefore, should be avoided.

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.

Chest pain in patients with 'normal angiography': could it be cardiac?

Approximately 20% of patients undergoing diagnostic angiography for the evaluation of chest pain are found to have a normal coronary angiogram. Although this finding is generally associated with a low risk of cardiac events, approximately half will continue to experience chest pain over the next 12 months. Therefore, the finding of normal angiography warrants further evaluation of the potential causes for the presenting chest pain if we are to improve the disability suffered by these patients. In this review, the potential non-cardiac and cardiac causes for the chest pain in patients with normal angiography are briefly discussed with an in-depth focus on coronary vasomotor disorders including coronary artery spasm (variant angina) and microvascular disorders such as syndrome X, microvascular angina, the coronary slow flow phenomenon and microvascular spasm.

Inflammation and microvascular dysfunction in cardiac syndrome X patients without conventional risk factors for coronary artery disease

OBJECTIVES

The aim of this study was to ascertain whether coronary microvascular dysfunction (CMD) and inflammation are related in cardiac syndrome X (CSX).

BACKGROUND

CMD can lead to CSX, defined as typical angina and transient myocardial ischemia despite normal coronary arteriograms. Inflammation has been suggested to play a role in the pathogenesis of myocardial ischemia in CSX.

METHODS

We assessed 21 CSX patients (age 52 ± 10 years; 17 women) without traditional cardiovascular risk factors and 21 matched apparently healthy control subjects. Positron emission tomography was used to measure myocardial blood flow (MBF) and coronary flow reserve (CFR) in response to intravenous adenosine, whereas high-sensitivity C-reactive protein (CRP) was measured to assess inflammation. Patients were subdivided a priori into 2 groups according to CRP concentrations at study entry (i.e., ≤3 or >3 mg/l).

RESULTS

There were no differences in resting (1.20 ± 0.23 ml/min/g vs. 1.14 ± 0.20 ml/min/g; p = 0.32) or hyperemic MBF (3.28 ± 1.02 ml/min/g vs. 3.68 ± 0.89 ml/min/g; p = 0.18) between CSX patients and the control group, whereas CFR was mildly reduced in CSX patients compared with the control group (2.77 ± 0.80 vs. 3.38 ± 0.80; p = 0.02). Patients with CRP >3 mg/l had more severe impairment of CFR (2.14 ± 0.33 vs. 3.16 ± 0.76; p = 0.001) and more ischemic electrocardiographic changes during adenosine administration than patients with lower CRP, and a negative correlation between CRP levels and CFR (r = -0.49, p = 0.02) was found in CSX patients.

CONCLUSIONS

CSX patients with elevated CRP levels had a significantly reduced CFR compared with the control group, which is indicative of CMD. Our study thus suggests a role for inflammation in the modulation of coronary microvascular responses in patients with CSX.

Role of inflammation and endothelial dysfunction in the pathogenesis of cardiac syndrome X

Chest pain with normal coronary arteriograms represents a major diagnostic and therapeutic challenge to contemporary cardiology. Cardiac syndrome X (CSX), defined as typical angina-like chest pain, a positive response to exercise stress testing and normal coronary arteriograms, encompasses patients with a variety of pathogenic mechanisms. Cardiac ischemia has been documented in approximately 25% of CSX patients and is associated with endothelial dysfunction and microvascular vasodilator abnormalities. Increased endothelin-1, a powerful vasoconstrictor, has been suggested to play a pathogenic role. There is a high prevalence of postmenopausal women with CSX and thus estrogen deficiency has also been proposed to represent a possible pathogenic mechanism. Inflammatory mechanisms and endothelial dysfunction at the coronary microvascular level appear to be important in the pathogenesis of CSX. Treatment with agents that have protective effects on the vasculature and also anti-inflammatory properties, such as statins and angiotensin-converting enzyme inhibitors have been effective in improving both symptoms and electrocardiographic signs of myocardial ischemia in patients with CSX. This review discusses the roles for endothelial dysfunction and inflammation in the pathogenesis of CSX, as well as the potential therapeutic implications of these mechanisms.