Inflammation, endothelial cell activation, and coronary microvascular dysfunction in women with chest pain and no obstructive coronary artery disease

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.

Circulating exosomal mir-16-2-3p is associated with coronary microvascular dysfunction in diabetes through regulating the fatty acid degradation of endothelial cells

BACKGROUND

Coronary microvascular dysfunction (CMD) is a frequent complication of diabetes mellitus (DM) characterized by challenges in both diagnosis and intervention. Circulating levels of microRNAs are increasingly recognized as potential biomarkers for cardiovascular diseases.

METHODS

Serum exosomes from patients with DM, DM with coronary microvascular dysfunction (DM-CMD) or DM with coronary artery disease (DM-CAD) were extracted for miRNA sequencing. The expression of miR-16-2-3p was assessed in high glucose-treated human aortic endothelial cells and human cardiac microvascular endothelial cells. Fluorescence in situ hybridization (FISH) was used to detect miR-16-2-3p within the myocardium of db/db mice. Intramyocardial injection of lentivirus overexpressing miR-16-2-3p was used to explore the function of the resulting gene in vivo. Bioinformatic analysis and in vitro assays were carried out to explore the downstream function and mechanism of miR-16-2-3p. Wound healing and tube formation assays were used to explore the effect of miR-16-2-3p on endothelial cell function.

RESULTS

miR-16-2-3p was upregulated in circulating exosomes from DM-CMD, high glucose-treated human cardiac microvascular endothelial cells and the hearts of db/db mice. Cardiac miR-16-2-3p overexpression improved cardiac systolic and diastolic function and coronary microvascular reperfusion. In vitro experiments revealed that miR-16-2-3p could regulate fatty acid degradation in endothelial cells, and ACADM was identified as a potential downstream target. MiR-16-2-3p increased cell migration and tube formation in microvascular endothelial cells.

CONCLUSIONS

Our findings suggest that circulating miR-16-2-3p may serve as a biomarker for individuals with DM-CMD. Additionally, miR-16-2-3p appears to alleviate coronary microvascular dysfunction in diabetes by modulating ACADM-mediated fatty acid degradation in endothelial cells.

Traditional chinese medicine in coronary microvascular disease

Coronary microvascular disease (CMVD) is common in patients with cardiovascular risk factors and is associated with an increased risk of adverse cardiovascular events. Although the study of CMVD in modern medicine is ongoing, there is still no effective treatment for it. Traditional Chinese medicine (TCM) has some clinical advantages based on syndrome differentiation and individualized treatment. In this review, we review the clinical significance, pathogenesis, and current treatments of CMVD and systematically summarize the clinical efficacy and potential action mechanisms of TCM for CMVD. In addition, the scientific problems that need to be solved urgently and the research strategy of TCM for CMVD are described. CMVD has great clinical significance, but there are still many gaps in the related research. This review aims to attract the attention of clinicians to CMVD and promote research on CMVD in TCM.

Gender-Related Differences in Chest Pain Syndromes in the Frontiers in CV Medicine Special Issue: Sex & Gender in CV Medicine

Coronary artery disease (CAD) is the leading cause of morbidity and mortality among both women and men, yet women continue to have delays in diagnosis and treatment. The lack of recognition of sex-specific biological and socio-cultural gender-related differences in chest pain presentation of CAD may, in part, explain these disparities. Sex and gender differences in pain mechanisms including psychological susceptibility, the autonomic nervous system (ANS) reactivity, and visceral innervation likely contribute to chest pain differences. CAD risk scores and typical/atypical angina characterization no longer appear relevant and should not be used in women and men. Women more often have ischemia with no obstructive CAD (INOCA) and myocardial infarction, contributing to diagnostic and therapeutic equipoise. Existing knowledge demonstrates that chest pain often does not relate to obstructive CAD, suggesting a more thoughtful approach to percutaneous coronary intervention (PCI) and medical therapy for chest pain in stable obstructive CAD. Emerging knowledge regarding the central and ANS and visceral pain processing in patients with and without angina offers explanatory mechanisms for chest pain and should be investigated with interdisciplinary teams of cardiologists, neuroscientists, bio-behavioral experts, and pain specialists. Improved understanding of sex and gender differences in chest pain, including biological pathways as well as sociocultural contributions, is needed to improve clinical care in both women and men.

Research progress on the molecular mechanism of coronary microvascular endothelial cell dysfunction

Coronary microvascular disease is a high-risk factor for many cardiovascular events. However, due to its high concealment and many etiologies, the current understanding of its pathophysiological mechanism is very limited, which greatly limits its clinical diagnosis and treatment. In the process of the occurrence and development of coronary microvascular disease, the damage of coronary microvascular endothelial cell (CMEC) is the core link. CMEC's stress, metabolism, inflammation and other dysfunctions have a causal relationship with coronary microvascular disease, and are also the main features of coronary microvascular disease in the early stage. This article mainly reviews the molecular mechanisms of CMEC damage.

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.

Left ventricular circumferential strain and coronary microvascular dysfunction: A report from the Women's Ischemia Syndrome Evaluation Coronary Vascular Dysfunction (WISE-CVD) Project

AIMS

Women with ischemia but no obstructive coronary artery disease (INOCA) often have coronary microvascular dysfunction (CMD). Left ventricular (LV) circumferential strain (CS) is often lower in INOCA compared to healthy controls; however, it remains unclear whether CS differs between INOCA women with and without CMD. We hypothesized that CS would be lower in women with CMD, consistent with CMD-induced LV mechanical dysfunction.

METHODS AND RESULTS

Cardiac magnetic resonance (cMR) images were examined from women enrolled in the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction Project. CS by feature tracking in INOCA women with CMD, defined as myocardial perfusion reserve index (MPRI) <1.84 during adenosine-stress perfusion cMR, was compared with CS in women without CMD. In a subset who had invasive coronary function testing (CFT), the relationship between CS and CFT metrics, LV ejection fraction (LVEF) and cardiovascular risk factors was investigated. Among 317 women with INOCA, 174 (55%) had CMD measured by MPRI. CS was greater in women with CMD compared to those without CMD (23.2 ± 2.5% vs. 22.1 ± 3.0%, respectively, P = 0.001). In the subset with CFT (n = 153), greater CS was associated with increased likelihood of reduced vasodilator capacity (OR = 1.33, 95%CI = 1.02-1.72, p = 0.03) and discriminated abnormal vs. normal coronary vascular function compared to CAD risk factors, LVEF and LV concentricity (AUC: 0.82 [0.73-0.96 95%CI] vs. 0.65 [0.60-0.71 95%CI], respectively, P = 0.007).

CONCLUSION

The data indicate that LV circumferential strain is related to and predicts CMD, although in a direction contrary with our hypothesis, which may represent an early sign of LV mechanical dysfunction in CMD.

Increased Inflammatory Activity in Patients 3 Months after Myocardial Infarction with Nonobstructive Coronary Arteries

BACKGROUND

Around 5%-10% of patients with myocardial infarction (MI) present with nonobstructive coronary arteries (MINOCA). We aimed to assess pathophysiological mechanisms in MINOCA by extensively evaluating cardiovascular biomarkers in the stable phase after an event, comparing MINOCA patients with cardiovascular healthy controls and MI patients with obstructive coronary artery disease (MI-CAD).

METHODS

Ninety-one biomarkers were measured with a proximity extension assay 3 months after MI in 97 MINOCA patients, 97 age- and sex-matched MI-CAD patients, and 98 controls. Lasso analyses (penalized logistic regression models) and adjusted multiple linear regression models were used for statistical analyses.

RESULTS

In the Lasso analysis (MINOCA vs MI-CAD), 8 biomarkers provided discriminatory value: P-selectin glycoprotein ligand 1, C-X-C motif chemokine 1, TNF-related activation-induced cytokine, and pappalysin-1 (PAPPA) with increasing probabilities of MINOCA, and tissue-type plasminogen activator, B-type natriuretic peptide, myeloperoxidase, and interleukin-1 receptor antagonist protein with increasing probabilities of MI-CAD. Comparing MINOCA vs controls, 7 biomarkers provided discriminatory value: N-terminal pro-B-type natriuretic peptide, renin, NF-κ-B essential modulator, PAPPA, interleukin-6, and soluble urokinase plasminogen activator surface receptor with increasing probabilities of MINOCA, and agouti-related protein with increasing probabilities of controls. Adjusted multiple linear regression analyses showed that group affiliation was associated with the concentrations of 7 of the 8 biomarkers in the comparison MINOCA vs MI-CAD and 5 of the 7 biomarkers in MINOCA vs controls.

CONCLUSIONS

Three months after the MI, the biomarker concentrations indicated greater inflammatory activity in MINOCA patients than in both MI-CAD patients and healthy controls, and a varying degree of myocardial dysfunction among the 3 cohorts.

Elevated renalase levels in patients with acute coronary microvascular dysfunction - A possible biomarker for ischemia

AIMS

We explored the relationship between inflammation, renalase an anti-inflammatory protein, and acute chest pain with coronary microvascular dysfunction (CMD).

METHODS AND RESULTS

We used cardiac Rb-82 PET/CT imaging to diagnose coronary artery disease (CAD/CALC) (defect or coronary calcification) and CMD (depressed coronary flow reserve without CAD) in patients with chest pain in an emergency department (ED). Blood samples were collected pre-imaging within 24 h of ED presentation and were analyzed for renalase and inflammatory markers including C-reactive protein, interleukins, interferon gamma, tumor necrosis factor, vascular endothelial growth factor, and metalloproteinases. Exclusions were age ≤30 years, myocardial infarction, hemodynamic instability, hypertensive crisis, heart failure or dialysis. Between 6/2014 and 11/2015, 80 patients undergoing PET/CT provided blood and were categorized as normal (18%), CAD/CALC (27%) and CMD (55%). Median renalase values were highest in patients with CMD (5503 ng/ml; IQR 3070) compared to patients with normal flows (4266 ng/ml; IQR 1503; p = 0.02) or CAD/CALC (4069 ng/ml IQR 1850; p = 0.004). CMD patients had similar median values for inflammatory markers as normal patients (p > 0.05). Renalase remained an independent predictor of CMD (OR 1.34; 95% CI = 1.1-1.7, per 1000 ng/ml) after adjustment for smoking, family history, obesity and Framingham risk score. In a model for CMD diagnosis with Framingham risk score, typical angina history and CRP, renalase improved discrimination from C-statistic = 0.60 (95% CI 0.47, 0.73) to 0.70 (95% CI, 0.59-0.82).

CONCLUSION

We found elevated renalase in response to ischemia from acute CMD. Its role as a biomarker needs validation in larger trials.

Left ventricular diastolic dysfunction in women with nonobstructive ischemic heart disease: insights from magnetic resonance imaging and spectroscopy

Ischemic heart disease, in the absence of obstructive coronary artery disease, is prevalent in women and constitutes a major risk factor for developing major adverse cardiovascular events, including myocardial infarction, stroke, and heart failure. For decades, diagnosis was considered benign and often minimized; however, it is now known that this etiology carries much risk and is a significant burden to the health care system. This review summarizes the current state of knowledge on nonobstructive ischemic heart disease (NOIHD), the association between NOIHD and left ventricular diastolic dysfunction, potential links between NOIHD and the development of heart failure with preserved ejection fraction (HFpEF), and therapeutic options and knowledge gaps for patients living with NOIHD.

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.

Myocardial tissue deformation is reduced in subjects with coronary microvascular dysfunction but not rescued by treatment with ranolazine

BACKGROUND

Patients with coronary microvascular dysfunction (CMD) often have diastolic dysfunction, representing an important therapeutic target. Ranolazine-a late sodium current inhibitor-improves diastolic function in animal models and subjects with obstructive coronary artery disease (CAD).

HYPOTHESIS

We hypothesized that ranolazine would beneficially alter diastolic function in CMD.

METHODS

To test this hypothesis, we performed retrospective tissue tracking analysis to evaluate systolic/diastolic strain, using cardiac magnetic resonance imaging cine images acquired in a recently completed, randomized, double-blind, placebo-controlled, crossover trial of short-term ranolazine in subjects with CMD and from 43 healthy reference controls.

RESULTS

Diastolic strain rate was impaired in CMD vs controls (circumferential diastolic strain rate: 99.9% ± 2.5%/s vs 120.1% ± 4.0%/s, P = 0.0003; radial diastolic strain rate: -199.5% ± 5.5%/s vs -243.1% ± 9.6%/s, P = 0.0008, case vs control). Moreover, peak systolic circumferential strain (CS) and radial strain (RS) were also impaired in cases vs controls (CS: -18.8% ± 0.3% vs -20.7% ± 0.3%; RS: 35.8% ± 0.7% vs 41.4% ± 0.9%; respectively; both P < 0.0001), despite similar and preserved ejection fraction. In contrast to our hypothesis, however, we observed no significant changes in left ventricular diastolic function in CMD cases after 2 weeks of ranolazine vs placebo.

CONCLUSIONS

The case-control comparison both confirms and extends our prior observations of diastolic dysfunction in CMD. That CMD cases were also found to have subclinical systolic dysfunction is a novel finding, highlighting the utility of this retrospective approach. In contrast to previous studies in obstructive CAD, ranolazine did not improve diastolic function in CMD.

Uric Acid Is Associated With Inflammation, Coronary Microvascular Dysfunction, and Adverse Outcomes in Postmenopausal Women

Uric acid is a risk factor for coronary artery disease in postmenopausal women, but the association with inflammation and coronary endothelial dysfunction (CED) is not well defined. The aim of this study was to determine the relationship of serum uric acid (SUA), inflammatory markers, and CED. In this prospective cohort study, SUA, high-sensitivity C-reactive protein levels, and neutrophil count were measured in 229 postmenopausal women who underwent diagnostic catheterization, were found to have no obstructive coronary artery disease, and underwent coronary microvascular function testing, to measure coronary blood flow response to intracoronary acetylcholine. The average age was 58 years (interquartile range, 52-66 years). Hypertension was present in 48%, type 2 diabetes mellitus in 5.6%, and hyperlipidemia in 61.8%. CED was diagnosed in 59% of postmenopausal women. Mean uric acid level was 4.7±1.3 mg/dL. Postmenopausal women with CED had significantly higher SUA compared with patients without CED (4.9±1.3 versus 4.4±1.3 mg/dL; P=0.02). There was a significant correlation between SUA and percent change in coronary blood flow to acetylcholine (P=0.009), and this correlation persisted in multivariable analysis. SUA levels were significantly associated with increased neutrophil count (P=0.02) and high-sensitivity C-reactive protein levels (P=0.006) among patients with CED, but not among those without CED. SUA is associated with CED in postmenopausal women and may be related to inflammation. These findings link SUA levels to early coronary atherosclerosis in postmenopausal women.

Renal function and coronary microvascular dysfunction in women with symptoms/signs of ischemia

OBJECTIVES

Chronic kidney disease (CKD) is more prevalent among women and is associated with adverse cardiovascular events. Among women with symptoms and signs of ischemia enrolled in the Women's Ischemia Syndrome Evaluation (WISE), a relatively high mortality rate was observed in those with no obstructive coronary artery disease. Coronary microvascular dysfunction or reduced coronary flow reserve (CFR) was a strong and independent predictor of adverse outcomes. The objective of this analysis was to determine if renal function was associated with coronary microvascular dysfunction in women with signs and symptoms of ischemia.

METHODS

The WISE was a multicenter, prospective, cohort study of women undergoing coronary angiography for suspected ischemia. Among 198 women with additional measurements of CFR, we determined the estimated glomerular filtration rate (eGFR) with the CKD-EPI equation. We tested the association between eGFR and CFR with regression analysis.

RESULTS

The median eGFR was 89 ml/min. The eGFR correlated with CFR (r = 0.22; P = 0.002). This association persisted even after covariate adjustment. Each 10-unit decrease in eGFR was associated with a 0.04-unit decrease in CFR (P = 0.04).There was a strong interaction between eGFR and age (P = 0.006): in those ≥60 years old, GFR was strongly correlated with CFR (r = 0.55; P<0.0001). No significant correlation was noted in those <60 years old.

CONCLUSIONS

Reduced renal function was significantly associated with lower CFR in women with symptoms and signs of ischemia. Coronary microvascular dysfunction warrants additional study as a mechanism contributing to increased risk of cardiovascular events in CKD.

[18F]fluorodeoxyglucose uptake in atherosclerotic plaques is associated with reduced coronary flow reserve in mice

OBJECTIVES

Coronary microvascular dysfunction, observed as impaired coronary vasodilator capacity, is an early manifestation of coronary artery disease. Inflammation plays an important role in different stages of atherogenesis. To study the role of vessel wall inflammation in the development of coronary dysfunction, we compared [(18)F]fluorodeoxyglucose (FDG) uptake in the aorta and coronary flow reserve (CFR) in atherosclerotic mice.

METHODS

We studied healthy young C57BL/6 mice fed a normal diet (n = 7) as well as hypercholesterolemic low-density lipoprotein receptor-disrupted/apolipoprotein B100-expressing (LDLR(-/-)ApoB(100/100)) mice (n = 15) and hypercholesterolemic and diabetic LDLR(-/-)ApoB(100/100)insulinlike growth factor II-overexpressing mice (n = 14) fed a western-type diet, aged 4 to 6 months. Doppler sonography was used to measure CFR as the ratio of coronary flow velocity during isoflurane-induced hyperemia and at rest. Uptake of [(18)F]FDG into the aorta was measured by autoradiography of tissue sections.

RESULTS

Histologic sections showed extensive atherosclerosis in the aorta, but coronary arteries were not obstructed. Both hyperemic coronary flow velocity and CFR were reduced (P < .05) in hypercholesterolemic mice with and without diabetes in comparison to healthy young C57BL/6 controls. Among hypercholesterolemic mice, both hyperemic flow velocity and CFR inversely correlated with atherosclerotic plaque [(18)F]FDG uptake in the aorta (r = -0.73; P < .001; r = -0.63; P = .001, respectively). In a multivariate analysis, including animal weight, aortic plaque burden, plasma glucose, plasma cholesterol, and [(18)F]FDG uptake in atherosclerotic plaques, only [(18)F]FDG uptake remained an independent predictor of reduced CFR (β = 0.736; P = .001).

CONCLUSIONS

The inflammatory activity in atherosclerotic plaques of the aorta independently predicts reduced CFR in atherosclerotic mice without obstructive coronary artery disease. This finding suggests that atherosclerotic inflammation contributes to coronary dysfunction.

Flow in the left anterior descending coronary artery in patients with migraine headache

Migraine is a common neurovascular disorder characterized by attacks of severe headache, autonomic and neurologic symptoms. Migraine can affect many systems in the body, yet its effects on cardiovascular system are unclear. We hypothesized that migraine and coronary microvascular angina may be manifestations of a common systemic microvascular dysfunction and clinically associated. Forty patients with migraine and 35 healthy volunteers were included into the study. Using transthoracic Doppler echocardiography, coronary flow was visualized in the middle or distal part of the left anterior descending artery. Coronary diastolic peak flow velocities were measured with pulse wave Doppler at baseline and after dipyridamole infusion (0.56 mg/kg/4 min). Coronary flow reserve of <2 was considered normal. In addition, thorough 2-dimensional and Doppler echocardiographic examinations were also performed. Fifty-two women and 23 men were included. Coronary flow reserve was significantly lesser in the migraine group than in the control group (1.99 ± 0.3 vs 2.90 ± 0.5, p <0.05). In addition, mitral annular velocities were lower and the ratio of early mitral inflow velocity to early mitral annular velocity (E/E' lateral and E/E' septal) was higher in migraineurs than in the control group (p <0.05 for all), indicating diastolic function abnormalities in the migraine group. In conclusion, these findings suggest that there is an association between coronary microvascular dysfunction and migraine independently of the metabolic state of the patients. A common pathophysiologic pathway of impaired endothelial vasodilatation, vasomotor dysfunction, and increased systemic inflammatory factors may play a role in these 2 clinical conditions and could be the underlying cause of subclinical systolic and diastolic left ventricular dysfunction in migraineurs.

Role of C-reactive protein in determining microvascular function in patients with non-ST-segment elevation acute coronary syndrome undergoing percutaneous coronary intervention

The extent of coronary microvascular dysfunction might be related, not only to patient characteristics and procedural factors, but also to the inflammatory status. The aim of the present study was to examine a possible association between inflammation, as reflected by the serum C-reactive protein (CRP) levels, and the extent of baseline and post-percutaneous coronary intervention (PCI) coronary microvascular dysfunction in patients with non-ST-segment elevation acute coronary syndrome undergoing PCI. A total of 42 patients undergoing PCI for non-ST-segment elevation acute coronary syndrome were enrolled. Coronary microvascular resistance (MR) was determined in the territory of culprit artery using a Doppler probe- and a pressure sensor-equipped guidewire both before (taking the collateral blood into account) and after PCI. The periprocedural changes in MR were calculated. The CRP levels at admission were correlated with the pre-PCI MR (r = 0.498, p = 0.001), post-PCI MR (r = 0.429, p = 0.005), and periprocedural changes in MR (r = 0.785, p <0.001). On multivariate regression analysis, the only predictor of the pre-PCI (β = 0.531, p = 0.002) and post-PCI (β = 0.471, p = 0.012) MR was the serum CRP concentration. Likewise, the periprocedural changes in MR was predicted by the serum CRP levels (β = 0.677, p = 0.001) and the presence of angiographic thrombus (β = -0.275, p = 0.02). In conclusion, these results have shown that the CRP level is related to increased coronary MR in the territory of the culprit lesion. This suggests that inflammatory processes might play a role in microvascular impairment in patients with non-ST-segment elevation acute coronary syndrome.

Unique vascular protective properties of natural products: supplements or future main-line drugs with significant anti-atherosclerotic potential?

Natural health products (NHP) which include minerals, vitamins and herbal remedies are not generally considered by medical practitioners as conventional medicines and as such are not frequently prescribed by health centre's as either main-line or supplemental treatments. In the field of cardiovascular medicine, studies have shown that typically, less than half of patients suffering from coronary syndromes chose to take any form of NHP supplement and these products are rarely recommended by their medical practitioner. Vascular/endothelial cell damage is a key instigator of coronary arterial plaque development which often culminates in thrombosis and myocardial infarction (MI). Current treatment for patients known to be at risk of primary or secondary (MI) includes lipid lowering statins, anti-clotting agents (e.g. tissue plasminogen activator; tPA) and drugs for stabilization of blood pressure such as beta-blockers. However, evidence has been building which suggests that components of at least several NHP (e.g. aged garlic extract (AGExt), resveratrol and green tea extracts (GTE)) may have significant vascular protective effects through reduction of oxidative stress, lowering of blood pressure, reduction in platelet aggregation, vasodilation and inhibition of abnormal angiogenesis. Therefore, in this review we will discuss in detail the potential of these substances (chosen on the basis of their potency and complimentarity) as anti-atherosclerotic agents and the justification for their consideration as main-line additional supplements or prescriptions.

The role of plasma aminothiols in the prediction of coronary microvascular dysfunction and plaque vulnerability

BACKGROUND

Although oxidative stress is considered a key pathogenic step in mediating vascular dysfunction and atherosclerosis development, their association has not been evaluated in human coronary circulation in vivo. Accordingly, we hypothesized that higher oxidative stress would be associated with abnormal coronary epicardial structure and microvascular function.

METHODS

We measured coronary flow velocity reserve (CFVR) and hyperemic microvascular resistance (HMR) as indices of microvascular function, and epicardial plaque volume and necrotic core using intravascular ultrasound (IVUS) in 47 patients undergoing cardiac catheterization. Plasma glutathione, cystine and their ratio served as measures of oxidative stress while high-sensitivity C-reactive protein (hs-CRP) served as a measure of inflammation.

RESULTS

Lower glutathione, a measure of increased oxidative stress was associated with impaired microvascular function [CFVR (r=0.39, p=0.01) and HMR (r=-0.43, p=0.004)], greater plaque burden (r=-0.32, p=0.03) and necrotic core (r=-0.39, p=0.008). Similarly, higher cystine/glutathione ratio was associated with impaired microvascular function [CFVR (r=-0.29, p=0.04)] and greater necrotic core (r=0.37, p=0.01). In comparison, higher hs-CRP was associated only with greater necrotic core (r=0.45, p=0.003). After multivariate adjustment for age, gender, hypertension, diabetes, acute coronary syndrome presentation, body mass index, tobacco abuse, statin use and hs-CRP, glutathione remained an independent predictor of CFVR, HMR and necrotic core (p<0.05).

CONCLUSIONS

Lower plasma glutathione level a measure of increased oxidative stress, was an independent predictor of impaired coronary microvascular function and plaque necrotic core.

Inflammation is related to coronary flow reserve detected by positron emission tomography in asymptomatic male twins

OBJECTIVES

This study sought to examine the relationship between inflammation and coronary microvascular function in asymptomatic individuals using positron emission tomography (PET) and assessment of coronary flow reserve (CFR).

BACKGROUND

Coronary microvascular dysfunction is an early precursor of coronary artery disease (CAD) thought to result from endothelial cell activation and inflammation, but data are limited.

METHODS

We examined 268 asymptomatic male monozygotic and dizygotic twins. Plasma biomarkers of inflammation and endothelial cell activation included C-reactive protein (CRP), interleukin (IL)-6, white blood cell count (WBC), vascular cell adhesion molecule (VCAM)-1, and intercellular adhesion molecule (ICAM)-1. Blood flow quantitation was obtained with [¹³N] ammonia PET at rest and after adenosine stress. CFR was measured as the ratio of maximum flow to baseline flow at rest; abnormal CFR was defined as a ratio < 2.5. A summed stress score for visible perfusion defects was calculated.

RESULTS

In within-pair analyses, all biomarkers, except VCAM-1, were higher in twins with lower CFR than their brothers with higher CFR (p < 0.05). This was observed in the entire sample, as well as within pairs discordant for a CFR of <2.5. Associations persisted after adjusting for summed stress score and CAD risk factors. In contrast no biomarker, except IL-6, was related to the summed stress score of visible defects.

CONCLUSIONS

Even in asymptomatic subjects, a decrease in coronary microvascular function is accompanied by a systemic inflammatory response, independent of CAD risk factors. Our results, using a controlled twin design, highlight the importance of coronary microvascular function in the early phases of CAD.

Gender and microvascular angina

There are gender differences in the presentation, diagnosis, and treatment of chest pain. When compared to men, women may have more atypical presentations of chest pain. In addition, current diagnostic tools are often not definitive regarding cardiac etiology for chest pain in women. The current diagnostic model of chest pain focuses on significant obstructions within the large coronary arteries as the cause for angina. Microvascular angina (MVA) represents an under-recognized pathophysiologic mechanism that may explain the apparent disparities and elucidate an etiology for the common finding in women of chest pain, ischemia on stress testing, and no obstructive coronary artery disease (CAD) on angiography in the presence of abnormal coronary reactivity testing. Endothelial dysfunction, estrogen deficiency, and abnormal nociception play a role in the pathophysiology of MVA. Treatments are targeted toward these underlying mechanisms. Recognizing the role gender and other pathophysiologic models of chest pain can play in the work-up and treatment of angina may identify a treatable cardiac condition, that would otherwise be discounted as non-cardiac in origin.

Gender-related differences in coronary artery dimensions: a volumetric analysis

BACKGROUND

Women consistently have poorer revascularization outcomes and more coronary vascular complications compared to men. This has been attributed to smaller coronary arteries, though limited data exist to support this assumption.

HYPOTHESIS

By using volumetric data obtained from multidetector cardiovascular computed tomography (CCT), we sought to determine to what extent gender influences coronary artery dimensions and test the hypothesis that women would have smaller coronary dimensions even after normalizing for body surface area and cardiac mass.

METHODS

CCT examinations completed on a 64-slice scanner were identified from a university cardiovascular database. Data sets from 50 women and 44 men without coronary artery disease were selected for analysis. Cross-sectional areas of proximal and distal segments of the left anterior descending (LAD), circumflex (LCx), and right coronary artery (RCA) were measured, blinded to patient gender. Measurements were compared using 2-sample t tests and linear regression analysis techniques accounting for body surface area (BSA) and left ventricular (LV) mass.

RESULTS

Analysis of cross-sectional coronary artery areas, unadjusted for BSA and LV mass showed smaller coronary artery size in women compared to men in the proximal portion of both the LAD (P = .01) and RCA (P = .002), but no significant difference in the remaining coronary segments.

CONCLUSION

Gender significantly impacts proximal LAD and RCA size. Differences in coronary artery dimensions may explain some, but not all excess gender-related risk with coronary artery revascularization, underscoring the importance of considering multiple contributing factors.

Noninvasive assessment of coronary microvascular function in women at risk for ischaemic heart disease

The primary objective of the current review is to describe the assessment of coronary microvascular function by noninvasive imaging techniques in women at risk for and with ischaemic heart disease (IHD). The search criteria were the analyses of the related bibliography published in PUBMED database. Normal or minimal obstructive coronary artery disease (CAD) at angiography is a common finding in women with signs of ischaemia. Up to 50% of them will have coronary microvascular dysfunction, suggesting that the mechanism of ischaemia may be localised at coronary microcirculation level. Noninvasive measurements of coronary microvascular function can be performed by radionuclide techniques. In particular, positron emission tomography (PET) measures myocardial blood flow (MBF) not only relatively but also in absolute units. Thus, PET offers the possibility to uncover microvascular dysfunction even in patients without obstructive CAD. PET-derived estimates of MBF showed an abnormal coronary microvascular function in women with chest pain and non-obstructive CAD and in women with high-risk conditions for CAD. Interestingly, there is a relationship between an abnormal coronary vascular function and adverse cardiovascular outcomes. In particular, this significant relationship was observed with measurements related to endothelial function. Recent evidence suggests that vascular dysfunction plays a central role as an estimator of outcomes in women at risk for or with IHD. Therefore, assessment of coronary vascular function in these women appears to be of clinical relevance. Whether such evaluation may have an impact to reduce cardiac events needs further investigation.

Risk factors for progression of peripheral arterial disease in large and small vessels

BACKGROUND

Data on the natural history of peripheral arterial disease (PAD) are scarce and are focused primarily on clinical symptoms. Using noninvasive tests, we assessed the role of traditional and novel risk factors on PAD progression. We hypothesized that the risk factors for large-vessel PAD (LV-PAD) progression might differ from small-vessel PAD (SV-PAD).

METHODS AND RESULTS

Between 1990 and 1994, patients seen during the prior 10 years in our vascular laboratories were invited for a new vascular examination. The first assessment provided baseline data, with follow-up data obtained at this study. The highest decile of decline was considered major progression, which was a -0.30 ankle brachial index decrease for LV-PAD and a -0.27 toe brachial index decrease for SV-PAD progression. In addition to traditional risk factors, the roles of high-sensitivity C-reactive protein, serum amyloid-A, lipoprotein(a), and homocysteine were assessed. Over the average follow-up interval of 4.6+/-2.5 years, the 403 patients showed a significant ankle brachial index and toe brachial index deterioration. In multivariable analysis, current smoking, ratio of total to HDL cholesterol, lipoprotein(a), and high-sensitivity C-reactive protein were related to LV-PAD progression, whereas only diabetes was associated with SV-PAD progression.

CONCLUSIONS

Risk factors contribute differentially to the progression of LV-PAD and SV-PAD. Cigarette smoking, lipids, and inflammation contribute to LV-PAD progression, whereas diabetes was the only significant predictor of SV-PAD progression.