Endothelial function predicts future development of coronary artery disease: a study of women with chest pain and normal coronary angiograms

Evaluation of coronary microvascular function by left ventricular contractile reserve with low-dose dobutamine echocardiography

AIMS

Coronary microvascular function has important diagnostic and prognostic implications but routine assessment is difficult. The index of microcirculatory resistance (IMR) is a reliable but invasive measure. We evaluated whether left ventricular contractile reserve (CR), measured with strain imaging on dobutamine echocardiography (DSE), is a reliable non-invasive measure of coronary microvascular function.

METHODS AND RESULTS

Forty-five patients underwent low-dose DSE and invasive coronary angiography with IMR measurement in the left anterior descending artery. Global mean peak systolic longitudinal strain was measured in three apical views at rest, and with low-dose DSE. CR was the difference between the resting and low-dose values. Mean IMR was 19.8 (range 6-104): mean peak global systolic strain at rest was -17.90% and at low-dose was -21.46%, giving a mean CR of +3.6% (20% relative increase). IMR and CR were significantly correlated, IMR(-1)=(0.0014×CR+0.05), r=0.64, p<0.001. CR of ≥10% relative increase identified IMR <25 (100% sensitivity and specificity) and <16 (93% sensitivity, 50% specificity [AUC=0.84]). CR ≥20% identified IMR of <16 (78% sensitivity, 82% specificity) with CR ≥ 41% having 100% specificity.

CONCLUSIONS

LV CR with low-dose DSE may be used to estimate IMR non-invasively. An impaired CR indicates coronary microvascular dysfunction.

Usefulness of brachial artery flow-mediated dilation to predict long-term cardiovascular events in subjects without heart disease

Endothelial dysfunction is considered an important prognostic factor in atherosclerosis. To determine the long-term association of brachial artery flow-mediated dilation (FMD) and adverse cardiovascular (CV) events in healthy subjects, we prospectively assessed brachial FMD in 618 consecutive healthy subjects with no apparent heart disease, 387 men (63%), and mean age 54 ± 11 years. After overnight fasting and discontinuation of all medications for ≥12 hours, FMD was assessed using high-resolution linear array ultrasound. Subjects were divided into 2 groups: FMD ≤11.3% (n = 309) and >11.3% (n = 309), where 11.3% is the median FMD, and were comparable regarding CV risk factors, lipoproteins, fasting glucose, C-reactive protein, concomitant medications, and Framingham 10-year risk score. In a mean clinical follow-up of 4.6 ± 1.8 years, the composite CV events (all-cause mortality, nonfatal myocardial infarction, hospitalization for heart failure or angina pectoris, stroke, coronary artery bypass grafting, and percutaneous coronary interventions) were significantly more common in subjects with FMD ≤11.3% rather than >11.3% (15.2% vs 1.2%, p = 0.0001, respectively). Univariate analysis demonstrated that the median FMD significantly predicted CV events (odds ratio 2.78, 95% CI 1.35 to 5.71, p <0.001). Multivariate analysis, controlling for traditional CV risk factors, demonstrated that median FMD was the best independent predictor of long-term CV adverse events (odds ratio 2.93, 95% CI 1.28 to 6.68, p <0.001). In conclusion, brachial artery median FMD independently predicts long-term adverse CV events in healthy subjects with no apparent heart disease in addition to those derived from traditional risk factor assessment.

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.

Number and function of bone-marrow derived angiogenic cells and coronary flow reserve in women without obstructive coronary artery disease: a substudy of the NHLBI-sponsored Women's Ischemia Syndrome Evaluation (WISE)

BACKGROUND

In women with ischemia and no obstructive coronary artery disease, the Women's Ischemic Syndrome Evaluation (WISE) observed that microvascular coronary dysfunction (MCD) is the best independent predictor of adverse cardiovascular events. Since coronary microvascular tone is regulated in part by endothelium, we hypothesized that circulating endothelial cells (CEC), which reflect endothelial injury, and the number and function of bone-marrow derived angiogenic cells (BMDAC), which could help repair damaged endothelium, may serve as biomarkers for decreased coronary flow reserve (CFR) and MCD.

METHODS

We studied 32 women from the WISE cohort. CFR measurements in response to intracoronary adenosine were taken as an index of MCD. We enumerated BMDAC colonies and CEC in peripheral blood samples. BMDAC function was assessed by assay of migration of CD34+ cells toward SDF-1 and measurement of bioavailable nitric oxide (NO). These findings were compared with a healthy reference group and also entered into a multivariable model with CFR as the dependent variable.

RESULTS

Compared with a healthy reference group, women with MCD had lower numbers of BMDAC colonies [16 (0, 81) vs. 24 (14, 88); P = 0.01] and NO [936 (156, 1875) vs. 1168 (668, 1823); P = 0.02]. Multivariable regression analysis showed strong correlation of CFR to the combination of BMDAC colony count and CD34+ cell function (migration and NO) (R(2) = 0.45; P<0.05).

CONCLUSIONS

The BMDAC function and numbers of BMDAC colonies are decreased in symptomatic women with MCD and are independently associated with CFR. These circulating cells may provide mechanistic insights into MCD in women with ischemia.

Presentation, management, and outcomes of ischaemic heart disease in women

Scientific interest in ischaemic heart disease (IHD) in women has grown considerably over the past 2 decades. A substantial amount of the literature on this subject is centred on sex differences in clinical aspects of IHD. Many reports have documented sex-related differences in presentation, risk profiles, and outcomes among patients with IHD, particularly acute myocardial infarction. Such differences have often been attributed to inequalities between men and women in the referral and treatment of IHD, but data are insufficient to support this assessment. The determinants of sex differences in presentation are unclear, and few clues are available as to why young, premenopausal women paradoxically have a greater incidence of adverse outcomes after acute myocardial infarction than men, despite having less-severe coronary artery disease. Although differential treatment on the basis of patient sex continues to be described, the extent to which such inequalities persist and whether they reflect true disparity is unclear. Additionally, much uncertainty surrounds possible sex-related differences in response to cardiovascular therapies, partly because of a persistent lack of female-specific data from cardiovascular clinical trials. In this Review, we assess the evidence for sex-related differences in the clinical presentation, treatment, and outcome of IHD, and identify gaps in the literature that need to be addressed in future research efforts.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The vascular smooth muscle cell: a therapeutic target in Type 2 diabetes?

The rising epidemic of T2DM (Type 2 diabetes mellitus) worldwide is of significant concern. The inherently silent nature of the disease in its early stages precludes early detection; hence cardiovascular disease is often established by the time diabetes is diagnosed. This increased cardiovascular risk leads to significant morbidity and mortality in these individuals. Progressive development of complications as a result of previous exposure to metabolic disturbances appears to leave a long-lasting impression on cells of the vasculature that is not easily reversed and is termed 'metabolic memory'. SMCs (smooth muscle cells) of blood vessel walls, through their inherent ability to switch between a contractile quiescent phenotype and an active secretory state, maintain vascular homoeostasis in health and development. This plasticity also confers SMCs with the essential capacity to adapt and remodel in pathological states. Emerging clinical and experimental studies propose that SMCs in diabetes may be functionally impaired and thus contribute to the increased incidence of macrovascular complications. Although this idea has general support, the underlying molecular mechanisms are currently unknown and hence are the subject of intense research. The aim of the present review is to explore and evaluate the current literature relating to the problem of vascular disease in T2DM and to discuss the critical role of SMCs in vascular remodelling. Possibilities for therapeutic strategies specifically at the level of T2DM SMCs, including recent novel advances in the areas of microRNAs and epigenetics, will be evaluated. Since restoring glucose control in diabetic patients has limited effect in ameliorating their cardiovascular risk, discovering alternative strategies that restrict or reverse disease progression is vital. Current research in this area will be discussed.

Persistent angina: highly prevalent and associated with long-term anxiety, depression, low physical functioning, and quality of life in stable angina pectoris

AIMS

To evaluate persistent angina in stable angina pectoris with no obstructive coronary artery disease (CAD) compared to obstructive CAD and its relation to long-term anxiety, depression, quality of life (QOL), and physical functioning.

METHODS AND RESULTS

We invited 357 patients (men = 191; women = 166; response rate 83 %) with no prior cardiovascular disease who had a first-time coronary angiography (CAG) in 2008-2009 due to suspected stable angina to participate in a questionnaire survey in 2011 with the Seattle Angina Questionnaire and the Hospital Anxiety and Depression Scale as key elements. Long-term persistent angina (i.e., symptoms at least once a month) was present in 64 % of patients with diffuse non-obstructive CAD (1-49 % stenosis), 49 % of patients with normal coronary arteries (0 % stenosis), and 41 % of patients with obstructive CAD (≥ 50 % stenosis) (P = 0.01). Depression and anxiety were more common in patients with persistent angina: 24 versus 7 % (P < 0.001) reported HADS-Depression-scores >7 and 42 versus 21 % (P < 0.001) reported HADS-Anxiety-scores >7. In multivariate regression models, persistent angina was associated with depression (OR 4.3, 95 % confidence interval (CI) 1.9-9.6, P < 0.001), anxiety (OR 2.9, 95 % CI 1.6-5.1, P < 0.001), the severity of persistent angina with impaired physical functioning (P < 0.001), and QOL (P < 0.001); whereas outcomes were not related to age, gender, or degree of CAD.

CONCLUSIONS

The study indicates higher prevalence of persistent angina in patients with diffuse non-obstructive CAD or normal coronary arteries than in patients with obstructive CAD. Persistent angina symptoms were associated with long-term anxiety, depression, impaired physical functioning, and QOL irrespective of the degree of CAD. Contrary to common perception, excluding obstructive CAD in stable angina does not ensure a favorable disease course, and further risk stratification and treatment strategies are warranted.

Acute effects of hemodialysis on nitrite and nitrate: potential cardiovascular implications in dialysis patients

Cardiovascular mortality in dialysis patients remains a serious problem. It is 10 to 20 times higher than in the general population. No molecular mechanism has been proven to explain this increased mortality, although nitric oxide (NO) has been implicated. The objective of our study was to determine the extent of the removal of the NO congeners nitrite and nitrate from plasma and saliva by hemodialysis, as this might disrupt physiological NO bioactivity and help explain the health disparity in dialysis patients. Blood and saliva were collected at baseline from patients on dialysis and blood was collected as it exited the dialysis unit. Blood and saliva were again collected after 4-5h of dialysis. In the 27 patients on dialysis, baseline plasma nitrite and nitrate by HPLC were 0.21±0.03 and 67.25±14.68 μM, respectively. Blood immediately upon exit from the dialysis unit had 57% less nitrite (0.09±0.03 μM; P=0.0008) and 84% less nitrate (11.04 μM; P=0.0003). After 4-5h of dialysis, new steady-state plasma levels of nitrite and nitrate were significantly lower than baseline, 0.09±0.01 μM (P=0.0002) and 16.72±2.27 μM (P=0.001), respectively. Dialysis also resulted in a significant reduction in salivary nitrite (232.58±75.65 to 25.77±10.88 μM; P=0.01) and nitrate (500.36±154.89 to 95.08±24.64 μM; P=0.01). Chronic and persistent depletion of plasma and salivary nitrite and nitrate probably reduces NO bioavailability and may explain in part the increased cardiovascular mortality in the dialysis patient.

Metabolomic analyses for atherosclerosis, diabetes, and obesity

Insulin resistance associated with type 2 diabetes mellitus (T2DM), obesity, and atherosclerosis is a global health problem. A portfolio of abnormalities of metabolic and vascular homeostasis accompanies T2DM and obesity, which are believed to conspire to lead to accelerated atherosclerosis and premature death. The complexity of metabolic changes in the diseases presents challenges for a full understanding of the molecular pathways contributing to the development of these diseases. The recent advent of new technologies in this area termed “Metabolomics” may aid in comprehensive metabolic analysis of these diseases. Therefore, metabolomics has been extensively applied to the metabolites of T2DM, obesity, and atherosclerosis not only for the assessment of disease development and prognosis, but also for the biomarker discovery of disease diagnosis. Herein, we summarize the recent applications of metabolomics technology and the generated datasets in the metabolic profiling of these diseases, in particular, the applications of these technologies to these diseases at the cellular, animal models, and human disease levels. In addition, we also extensively discuss the mechanisms linking the metabolic profiling in insulin resistance, T2DM, obesity, and atherosclerosis, with a particular emphasis on potential roles of increased production of reactive oxygen species (ROS) and mitochondria dysfunctions.

Heart rate variability today

Heart rate variability (HRV) non-invasively assesses the activity of the autonomic nervous system. During the past 30 years, an increasing number of studies have related the imbalance of the autonomic nervous system (as assessed by HRV) to several pathophysiogical conditions, particularly in the setting of cardiovascular disease. Sudden death, coronary artery disease, heart failure, or merely cardiovascular risk factors (smoking, diabetes, hyperlipidemia, and hypertension) are the best-known clinical circumstances that can affect and/or be affected by the autonomic nervous system. Analyses of HRV variables have been proposed as a component of the clinical evaluation for patient risk stratification due to its independent prognostic information. Yet the potential for HRV to be used widely in clinical practice remains to be established.

Coronary autoregulation is abnormal in syndrome X: insights using myocardial contrast echocardiography

BACKGROUND

Syndrome X in women is thought to be caused by coronary microvascular dysfunction, the exact site of which is unknown. The aim of this study was to characterize the microvascular site of dysfunction in these patients using myocardial contrast echocardiography.

METHODS

Women with exertional angina, positive test results on stress imaging, but no coronary artery disease (the study group, n = 18) and age-matched control women also with no coronary artery disease (n = 17) were enrolled. Myocardial contrast echocardiography was performed at rest and during dipyridamole-induced hyperemia. Mean microbubble velocity (β) and myocardial blood volume (A) were measured, and myocardial blood flow (A · β) was computed. In addition, plasma concentrations of eicosanoids, female sex hormones, and C-reactive protein were measured.

RESULTS

Rest β and myocardial blood flow (A · β) were higher in the study compared with the control women (1.61 ± 0.68 vs. 0.74 ± 0.44, P = .0001, and 157 ± 121 vs. 54 ± 54, P = 0.0001, respectively) despite similar heart rates and systolic blood pressures. After the administration of dipyridamole, whereas the changes in A and A · β were not significantly different between the two groups, β reserve (the ratio of stress β to rest β) was markedly lower in the study group (1.48 ± 0.62 vs. 2.78 ± 0.94, P = .0001). Blood hematocrit, eicosanoids, female sex hormones, glucose, and C-reactive protein were not different between the two groups.

CONCLUSIONS

Coronary autoregulation is abnormal in patients with syndrome X (higher resting β and myocardial blood flow and lower β reserve), which suggests that the coronary resistance vessels are the site of microvascular abnormality.

Long-term prognosis of patients with cardiac syndrome X: a review

Aims

Follow-up studies of patients with cardiac syndrome X (CSX) generally report good prognosis. However, some recent studies report an adverse outcome for women.

Methods and results

Structured literature search and meta-analysis for studies regarding prognosis of cardiac syndrome X patients. We identified 85 studies, ultimately selecting 16 for inclusion. Meta-analysis yielded a pooled major cardiac event percentage of 1.5% per 5 years and a pooled vascular event percentage of 4.8% per 5 years (n = 16 studies, n = 1694 patients). Fourteen studies reported upon the recurrence rate of angina pectoris: the pooled percentage of angina recurrence was 55% (n = 1336 patients).

Conclusion

The present review of recent archival literature demonstrates an overall major cardiac event rate of 1.5% per 5 years. Although this is an excellent prognosis for CSX patients, the quality of life is impaired because of the high recurrence rate of angina pectoris (55%).

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.

Novel role of the IGF-1 receptor in endothelial function and repair: studies in endothelium-targeted IGF-1 receptor transgenic mice

We recently demonstrated that reducing IGF-1 receptor (IGF-1R) numbers in the endothelium enhances nitric oxide (NO) bioavailability and endothelial cell insulin sensitivity. In the present report, we aimed to examine the effect of increasing IGF-1R on endothelial cell function and repair. To examine the effect of increasing IGF-1R in the endothelium, we generated mice overexpressing human IGF-1R in the endothelium (human IGF-1R endothelium-overexpressing mice [hIGFREO]) under direction of the Tie2 promoter enhancer. hIGFREO aorta had reduced basal NO bioavailability (percent constriction to N(G)-monomethyl-l-arginine [mean (SEM) wild type 106% (30%); hIGFREO 48% (10%)]; P < 0.05). Endothelial cells from hIGFREO had reduced insulin-stimulated endothelial NO synthase activation (mean [SEM] wild type 170% [25%], hIGFREO 58% [3%]; P = 0.04) and insulin-stimulated NO release (mean [SEM] wild type 4,500 AU [1,000], hIGFREO 1,500 AU [700]; P < 0.05). hIGFREO mice had enhanced endothelium regeneration after denuding arterial injury (mean [SEM] percent recovered area, wild type 57% [2%], hIGFREO 47% [5%]; P < 0.05) and enhanced endothelial cell migration in vitro. The IGF-1R, although reducing NO bioavailability, enhances in situ endothelium regeneration. Manipulating IGF-1R in the endothelium may be a useful strategy to treat disorders of vascular growth and repair.

ABO-Rh blood groups distribution in cardiac syndrome X patients

Background:

Data on frequency distribution of ABO-Rh blood groups in cardiac syndrome X (CSX) patients are not available. We aimed to investigate the distribution of ABO-Rh blood groups in these patients.

Materials and Methods:

A total of 247 CSX patients’ records were reviewed in a cross-sectional study from 2006 to 2010. One hundred forty six patients (59.1%) were female, and the mean patient age was 52 ± 11 years. The frequency of ABO-Rh blood groups was compared to the frequency of these blood groups in the West-Azerbaijan province, Iran; general population.

Results:

Blood groups distribution among CSX patients showed phenotypes A, B, AB, O and Rh negative as 33.1%, 21.9%, 9.3%, 35.8%, and 7.9%, respectively. According to our results, there were no differences in ABO-Rh blood groups distribution between CSX patients and normal population.

Conclusion:

These data suggest that ABO-Rh blood groups might be unassociated with CSX.

Nitric oxide and geriatrics: Implications in diagnostics and treatment of the elderly

The nation's aging population is growing rapidly. By 2030, the number of adults age 65 and older will nearly double to 70 million. Americans are living longer and older adults can now live for many years with multiple chronic illnesses but with a substantial cost to health care. Twenty percent of the Medicare population has at least five chronic conditions i.e., hypertension, diabetes, arthritis, etc. Studies in experimental models and even humans reveal that constitutive production of nitric oxide (NO) is reduced with aging and this circumstance may be relevant to a number of diseases that plague the aging population. NO is a multifunctional signaling molecule, intricately involved with maintaining a host of physiological processes including, but not limited to, host defense, neuronal communication and the regulation of vascular tone. NO is one of the most important signaling molecules in our body, and loss of NO function is one of the earliest indicators or markers of disease. Clinical studies provide evidence that insufficient NO production is associated with all major cardiovascular risk factors, such as hyperlipidemia, diabetes, hypertension, smoking and severity of atherosclerosis, and also has a profound predictive value for disease progression including cardiovascular and Alzheimers disease. Thirty plus years after its discovery and over 13 years since a Nobel Prize was awarded for its discovery, there have been no hallmark therapeutic breakthroughs or even NO based diagnostics. We will review the current state of the science surrounding NO in the etiology of a number of different diseases in the geriatric patient. From these observations, it can be concluded that enzymatic production of NO declines steadily with increasing age in healthy human subjects. Implementing strategies to diagnose and treat NO insufficiency may provide enormous benefit to the geriatric patient.

Spreading the signal for vasodilatation: implications for skeletal muscle blood flow control and the effects of ageing

Blood flow control requires coordinated contraction and relaxation of smooth muscle cells (SMCs) along and among the arterioles and feed arteries that comprise vascular resistance networks. Whereas smooth muscle contraction of resistance vessels is enhanced by noradrenaline release along perivascular sympathetic nerves, the endothelium is integral to coordinating smooth muscle relaxation. Beyond producing nitric oxide in response to agonists and shear stress, endothelial cells (ECs) provide an effective conduit for conducting hyperpolarization along vessel branches and into surrounding SMCs through myoendothelial coupling. In turn, bidirectional signalling from SMCs into ECs enables the endothelium to moderate adrenergic vasoconstriction in response to sympathetic nerve activity. This review focuses on the endothelium as the cellular pathway that coordinates spreading vasodilatation. We discuss the nature and regulation of cell-to-cell coupling through gap junctions, bidirectional signalling between ECs and SMCs, and how oxidative stress during ageing may influence respective signalling pathways. Our recent findings illustrate the role of small (SK(Ca)) and intermediate (IK(Ca)) Ca(2+) activated K(+) channels as modulators of electrical conduction along the endothelium. Gaps in current understanding indicate the need to determine mechanisms that regulate intracellular Ca(2+) homeostasis and ion channel activation in the resistance vasculature with advancing age.

Cardiac syndrome X and microvascular coronary dysfunction

Women with cardiac chest pain indicated by signs and symptoms of myocardial ischemia in the absence of obstructive CAD are often labelled as cardiac syndrome X (CSX). A subset of patients with CSX may have symptoms of ischemia due to microvascular dysfunction. Angina due to microvascular coronary dysfunction (MCD) is an etiologic mechanism in women with vascular dysfunction. New data provide improve understanding of coronary vascular dysfunction and resultant myocardial ischemia that characterize MCD among patients with cardiac syndrome X. MCD has an adverse prognosis and health care cost expenditure comparable to obstructive CAD. The high prevalence of this condition, particularly in women, adverse prognosis and substantial health care costs, coupled with a lack of evidence regarding treatment strategies, places MCD as a research priority area.

Myocardial ischemia in women: lessons from the NHLBI WISE study

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

Assessing coronary disease in symptomatic women by the Morise score

BACKGROUND

Early identification of coronary artery disease (CAD) among symptomatic women is critical given their worse outcomes as compared to men. We evaluated the value of the Morise score, a simple clinical risk score, for the assessment for CAD as determined by computed tomography coronary angiography (CTCA) and compared it to the Diamond-Forrester risk assessment.

METHODS

One hundred forty women (mean age, 64±11 years) with chest pain syndromes and no known CAD referred for CTCA were analyzed. Patients were risk stratified for likelihood of CAD by Morise and Diamond-Forrester scores. The presence and degree of CAD were determined by CTCA and classified as normal, nonobstructive (<50% stenosis), or obstructive (>50% stenosis). Total coronary calcium was calculated based on Agatston scores.

RESULTS

When risk was assessed by Morise vs. Diamond-Forrester, 5% vs. 7% of women were stratified as low, 41% vs. 82% as intermediate, and 54% vs. 11% as high risk for CAD, respectively. CAD was present in 95 (68%) patients; 22 (16%) had obstructive CAD, and 73 (52%) had nonobstructive CAD. Morise scores significantly correlated with calcium scores (p<0.001) as well as the presence and degree of CAD (p<0.0001). Morise scores also demonstrated significantly higher accuracy (66% vs. 48%, p<0.005) and higher sensitivity (56% vs. 16%, p<0.001) but lower specificity (82% vs. 97%, p<0.05) when compared to Diamond-Forrester risk assessment.

CONCLUSIONS

The Morise score performed better than Diamond-Forrester for CAD risk assessment, which highlights the importance and power of a simple history and physical examination in determining women at risk for CAD.

Weight is an independent predictor of vascular injury in healthy volunteers with aspartate allele

BACKGROUND

Endothelial dysfunction and carotid intima-media thickeness (IMT) are currently considered key early events in atherogenesis and markers of arterial damage. We investigated whether endothelial nitric oxide synthase (eNOS) glutamate (Glu)298-aspartate (Asp) polymorphism may influence the vascular response to weight, as measured by BMI, in young, healthy individuals.

METHODS

One hundred young (30.6 ± 5.9 years) healthy individuals, without concomitant traditional cardiovascular risk factors took part in the study. Brachial artery endothelial function was assessed by vascular response to reactive hyperemia [flow-mediated dilation (FMD) and sublingual nitroglycerin (GTN)-mediated dilation] using high-resolution ultrasound. Carotid IMT was also measured.

RESULTS

Participants were grouped as Glu-homozygotes (n = 38) and Asp-carriers (n = 62). On univariate analysis, a higher response to GTN was associated with lower brachial baseline diameter (P < 0.001) and increasing value of high-density lipoprotein cholesterol (P = 0.04) in Asp-carriers, but not in Glu-homozygotes. Higher FMD correlated with lower brachial baseline diameter (P < 0.001), BMI (P = 0.03) and SBP (P = 0.03) in the Asp-carriers, but not in Glu-homozygotes. Higher IMT showed a similar Asp-genotype-dependent association with higher BMI (P = 0.001), SBP (P = 0.006) and DBP (P = 0.001). In individuals with Asp-alleles, the multivariate analysis showed that BMI was the only independent predictor of IMT.

CONCLUSION

Weight is independently associated with impaired arterial structure in healthy and genetically predisposed young individuals. The allelic variation (Asp298) of the eNOS gene polymorphism makes individuals vulnerable to the impact of weight on the development of atherosclerosis.

Perspectives of Targeting mTORC1-S6K1 in Cardiovascular Aging

The global population aging is accelerating and age-associated diseases including cardiovascular diseases become more challenging. The underlying mechanisms of aging and age-associated cardiovascular dysfunction remain elusive. There are substantial evidences demonstrating a pivotal role of the mammalian target of rapamycin complex 1 (mTORC1) and its down-stream effector S6K1 signaling in mammalian lifespan regulation and age-related diseases such as type II diabetes mellitus and cancer. The role of mTORC1–S6K1 in age-related cardiovascular diseases is, however, largely unknown and the available experimental results are controversial. This review article primarily summarizes the most recent advances toward understanding the role of mTORC1–S6K1 in cardiovascular aging and discusses the future perspectives of targeting mTORC1–S6K1 signaling as a healthy lifespan extension modality in anti-aging and anti-cardiovascular aging.

Change of coronary flow velocity during the cold pressor test is related to endothelial markers in subjects with chest pain and a normal coronary angiogram

BACKGROUND

Several studies demonstrated that endothelial or atherosclerotic biomarkers, including plasma free insulin-like growth factor-I(IGF-I), soluble CD40 ligand (sCD40L), adiponectin, and leptin have an influence on coronary endothelial function.

HYPOTHESIS

The aim of the present study was to investigate whether change of coronary flow velocity of the distal left anterior descending artery (LAD) during the cold pressor test (CPT) with transthoracic Doppler echocardiography (TTE) was associated with these biomarkers in subjects with chest pain and a normal coronary angiogram.

METHODS

In 190 subjects (mean age, 54±11 years; male:female, 113:77) with chest pain and a normal coronary angiogram, peak diastolic velocity (PDV) of the distal LAD during the CPT with TTE was assessed. Acetylcholine provocation test was performed in 58 subjects (mean age, 51±10 years) who were clinically suspected of vasospasm. CPT%PDV was defined as the percent change in PDV during the CPT. Associations between CPT%PDV and clinical parameters were analyzed.

RESULTS

According to multiple regression analysis, CPT%PDV was associated with plasma free IGF-I in the entire study population (β=0.295, P<0.001 in all subjects; β=0.341, P=0.001 in males; β=0.243, P=0.037 in females; β=0.303, P=0.002 in nonsmokers; and β=0.256, P=0.047 in smokers), and sCD40L in males (β=-0.269, P=0.008)and smokers (β=-0.261, P=0.046). Subjects with vasospasm to intracoronary acetylcholine had lower plasma free IGF-I(6.9±3.3 vs 8.9±3.4, P=0.026) and CPT%PDV (8.8±24.9 vs 52.7±26.0, P<0.001) than the others. Plasma adiponectin and leptin were not associated with CPT%PDV.

CONCLUSIONS

Change of coronary flow velocity assessed using the CPT with TTE may be related to endothelial markers, especially plasma free IGF-I.

Stable angina pectoris with no obstructive coronary artery disease is associated with increased risks of major adverse cardiovascular events

AIMS

Patients with chest pain and no obstructive coronary artery disease (CAD) are considered at low risk for cardiovascular events but evidence supporting this is scarce. We investigated the prognostic implications of stable angina pectoris in relation to the presence and degree of CAD with no obstructive CAD in focus.

METHODS AND RESULTS

We identified 11 223 patients referred for coronary angiography (CAG) in 1998-2009 with stable angina pectoris as indication and 5705 participants from the Copenhagen City Heart Study for comparison. Main outcome measures were major adverse cardiovascular events (MACE), defined as cardiovascular death, myocardial infarction, stroke or heart failure, and all-cause mortality. Significantly more women (65%) than men (32%) had no obstructive CAD (P< 0.001). In Cox's models adjusted for age, body mass index, diabetes, smoking, and use of lipid-lowering or antihypertensive medication, hazard ratios (HRs) associated with no obstructive CAD were similar in men and women. In the pooled analysis, the risk of MACE increased with increasing degrees of CAD with multivariable-adjusted HRs of 1.52 (95% confidence interval, 1.27-1.83) for patients with normal coronary arteries and 1.85 (1.51-2.28) for patients with diffuse non-obstructive CAD compared with the reference population. For all-cause mortality, normal coronary arteries and diffuse non-obstructive CAD were associated with HRs of 1.29 (1.07-1.56) and 1.52 (1.24-1.88), respectively.

CONCLUSION

Patients with stable angina and normal coronary arteries or diffuse non-obstructive CAD have elevated risks of MACE and all-cause mortality compared with a reference population without ischaemic heart disease.