Coronary microvascular reactivity to adenosine predicts adverse outcome in women evaluated for suspected ischemia results from the National Heart, Lung and Blood Institute WISE (Women's Ischemia Syndrome Evaluation) study

Small and large vessel disease in persons with unrecognized compared to recognized myocardial infarction: The Tromsø Study 2007-2008

BACKGROUND

Unrecognized myocardial infarction (MI) is a frequent condition with unknown underlying reason. We hypothesized the lack of recognition of MI is related to pathophysiology, specifically differences in underlying small and large vessel disease.

METHODS

6128 participants were examined with retinal photography, ultrasound of the carotid artery and a 12‑lead electrocardiography (ECG). Small vessel disease was defined as narrower retinal arterioles and/or wider retinal venules measured on retinal photographs. Large vessel disease was defined as carotid artery pathology. We defined unrecognized MI as ECG-evidence of MI without a clinically recognized event. We analyzed the cross-sectional relationship between MI recognition and markers of small and large vessel disease, adjusted for age and sex.

RESULTS

Unrecognized MI was present in 502 (8.2%) and recognized MI in 326 (5.3%) of the 6128 participants. Compared to recognized MI, unrecognized MI was associated with small vessel disease indicated by narrower retinal arterioles (OR 1.66, 95% CI 1.05-2.62, highest vs. lowest quartile). Unrecognized MI was less associated with wider retinal venules (OR 0.55, 95% CI 0.35-0.87, lowest vs. highest quartile). Compared to recognized MI, unrecognized MI was less associated with large vessel disease indicated by presence of plaque in the carotid artery (OR for presence of carotid artery plaque in unrecognized MI 0.51, 95% CI 0.37-0.69). No significant sex interaction was present.

CONCLUSIONS

Unrecognized MI was more associated with small vessel disease and less associated with large vessel disease compared to recognized MI. These findings suggest that the pathophysiology behind unrecognized and recognized MI may differ.

Cardiac Microvascular Dysfunction in Women Living With HIV Is Associated With Cytomegalovirus Immunoglobulin G

Background

People living with HIV (PLWH) appear to be at increased risk of cardiovascular disease (CVD), and this is possibly more pronounced in women living with HIV (WLWH). In the general population, men are more likely to develop obstructive coronary artery disease (CAD), and women often present with a nonobstructive pattern with cardiac microvascular dysfunction. We investigated cardiac microvascular function in men and women living with HIV and tested for association with cytomegalovirus (CMV) immunoglobulin G (IgG), as this has been associated with CVD in PLWH.

Methods

In a cross-sectional study, 94 PLWH on antiretroviral therapy were scanned with ⁸²Rb positron emission tomography/computed tomography at rest and during adenosine-induced stress, which enables the quantification of the myocardial flow reserve (MFR). CMV IgG was measured in plasma.

Results

WLWH had significantly lower MFR compared with men living with HIV (MLWH; P = .003), and >45% of the women had an MFR indicative of cardiac microvascular dysfunction, whereas this was only true for 24% of men (P = .03). CMV IgG concentrations were inversely associated with MFR among WLWH but not MLWH (P = .05 for interaction).

Conclusions

In this first study comparing MFR in women and men living with HIV, we found that WLWH had significantly lower MFR than MLWH and 45% of the women had cardiac microvascular dysfunction despite younger age and lower cardiovascular risk. Furthermore, CMV IgG was inversely associated with MFR among women but not men. This calls for attention to CVD among young WLWH even with low cardiovascular risk.

Women's health: making cardiovascular disease real

PURPOSE OF REVIEW

When patients are seen for persistent chest pain in the absence of obstructive coronary artery disease, the physician must decide if the symptoms are due to myocardial ischemia in order to guide treatment.

RECENT FINDINGS

Recent findings indicate that ischemia due to coronary microvascular dysfunction (CMD) is associated with subclinical coronary atherosclerosis and an adverse prognosis. Therapeutic probe trials suggest that antiatherosclerotic and anti-ischemic therapeutic strategies may be useful. A large randomized clinical trial of high-intensity statin, maximally tolerated angiotensin-converting-enzyme inhibitor or angiotensin receptor blocker and low-dose aspirin (WARRIOR NCT#03417388) is in progress.

SUMMARY

The diagnosis of CMD should be considered in patients with persistent angina, evidence of myocardial ischemia and normal coronary angiogram. Because of the associated adverse prognosis of CMD , conservative empiric treatment or further diagnostic evaluation of the coronary microvasculature can be performed. Diagnosis involves the measurement of coronary blood blow in response to a vasodilator agent invasively or noninvasively. Treatment of CMD can include the use of traditional antianginal and antiatherosclerotic medications. Clinical trials are needed to assess therapeutic strategies on the outcomes of cardiovascular disease and quality of life, in order to develop evidence-based guidelines.

Physiological Consequences of Coronary Arteriolar Dysfunction and Its Influence on Cardiovascular Disease

To date, the major focus of diagnostic modalities and interventions to treat coronary artery disease has been the large epicardial vessels. Despite substantial data showing that microcirculatory dysfunction is a strong predictor of future adverse cardiovascular events, very little research has gone into developing techniques for in vivo diagnosis and therapeutic interventions to improve microcirculatory function. In this review, we will discuss the pathophysiology of coronary arteriolar dysfunction, define its prognostic implications, evaluate the diagnostic modalities available, and provide speculation on current and potential therapeutic opportunities.

'Primary' Microvascular Angina: Clinical Characteristics, Pathogenesis and Management

Microvascular angina (MVA), i.e. angina caused by abnormalities of the coronary microcirculation, is increasingly recognised in clinical practice. The pathogenetic mechanisms of MVA are heterogeneous and may involve both structural and functional alterations of coronary microcirculation, and functional abnormalities may variably involve an impairment of coronary microvascular dilatation and an increased microvascular constrictor activity. Both invasive and non-invasive diagnostic tools exist to identify patients with MVA in clinical practice. Prognosis has been reported to be good in primary MVA patients, although the prognostic implications of coronary microvascular dysfunction (CMVD) in more heterogeneous populations of angina patients need further assessment. Management of primary MVA can be challenging, but pharmacological and non-pharmacological treatments exist that allow satisfactory control of symptoms in most patients.

Stable Ischemic Heart Disease in Women

PURPOSE OF THE REVIEW

Paradoxically, although women have a lower burden of coronary atherosclerosis, they experience more symptoms, more frequent hospitalizations, and a worse prognosis compared to men. This is in part due to biological variations in pathophysiology between the two sexes, and in part related to inadequate understanding of these differences, subconscious referral bias, and suboptimal application of existing women-specific guidelines. We sought to review the contemporary literature and provide an update on risk assessment, diagnosis, and management of IHD in women.

RECENT FINDINGS

IHD in women is often secondary to diffuse non-obstructive atherosclerosis, coronary spasm, inflammation, and endothelial and microvascular dysfunction, and less commonly due to the male pattern of flow-limiting epicardial stenosis. Both IHD patterns likely represent sex-specific manifestations of the same disease process. Additionally, there is a differential expression of risk factors and symptoms between men and women. Application of male-pattern IHD risk factors and presentation to women contributes to under-recognition, under-testing, and under-treatment of IHD in women compared to men. Traditional diagnostic evaluation has focused on detection of epicardial disease, amenable to revascularization. Our improved understanding of sex-specific pathophysiology of IHD has enabled us to also develop tools for detection of microvascular disease. Advances in stress MRI, flow quantification on stress PET, and provocative invasive angiography have filled this void and offer important diagnostic and prognostic information. Despite our improved understanding of sex-specific differences in presentation, risk factors, pathophysiology, diagnostic testing, and management strategies of IHD, women with IHD continue to experience worse outcomes than men. This disparity underscores the need for improved research and understanding of biological sex differences, elimination of subconscious gender bias in referral patterns, and improved application of existing research into clinical practice.

Serotonin Transporter Gene Polymorphism in Women With Suspected Ischemia

Introduction:

Association of serotonin transporter gene ( 5-HTTLPR) polymorphisms with adverse cardiovascular (CV) events in women with suspected ischemia has not yet been reported. We hypothesized an association of 5-HTTLPR polymorphisms with risk of adverse CV events in women with suspected ischemic heart disease (IHD) referred for coronary angiography enrolled in the Women’s Ischemia Syndrome Evaluation (WISE).

Method:

We studied clinical and angiographic data and DNA from a cohort of 437 Caucasian women enrolled in the WISE genotyped for the long (L) and short (S) variant of the 5-HTTLPR polymorphism. Women were followed yearly for adverse CV events (defined as first occurrence of all-cause death, myocardial infarction, stroke, or heart failure hospitalization) with data collected at WISE 10-year follow-up. Exploratory analyses compared outcomes between genotype groups.

Results:

A total of 437 women, with baseline, angiographic, and long-term follow-up data, were successfully genotyped. Their mean age was 58 ± 11 years and body mass index 29 ± 6; 54% had hypertension, 18% diabetes, 50% dyslipidemia, 20% depression history, and only 34% had obstructive CAD. At 8.9 years median follow-up, the SS genotype was associated with significantly increased risk of adverse CV event versus LL + LS (1.93, confidence interval [CI]: 1.03-3.61, P = .03). Results were not significant for all-cause death (hazard ratio: 1.63, CI: 0.91-2.93, P = .09).

Conclusion:

Among a cohort of Caucasian women with suspected IHD enrolled in the WISE, the SS homozygous genotype for the 5-HTTLPR polymorphism was associated with increased risk of adverse CV outcomes.

Potential Protective Mechanism in the Cardiac Microvascular Injury

Cardiac microvascular injury often occurs in patients with type 2 diabetes mellitus (T2DM) who develop hyperglycemia and hyperlipidemia. However, besides reported contradictory roles in cardiac diseases, the function of TRPV1 (transient receptor potential vanilloid 1) in cardiac microvessels is not well defined. This study was performed to determine the detailed role of TRPV1 in cardiac microvascular endothelial cells (CMECs) in T2DM. T2DM mice were established by multiple injections of low-dose streptozotocin and high-fat feeding. CMECs were cultured separately in mediums of normal glucose, high glucose (HG), high fatty acid (HF), and HG plus HF (HG-HF). HG-HF inhibited TRPV1 expression in CMECs, reducing cellular Ca2+ content ([Ca2+]i). T2DM impaired cardiac function, disturbed glucose uptake, and damaged microvascular barrier, which were further aggravated by TRPV1-/- Exposure to HG-HF, particularly in TRPV1-/- CMECs, led to a higher level of apoptosis and a lower level of nitric oxide production in viable CMECs. HG-HF markedly enhanced generation of reactive oxygen species and nitrotyrosine, especially in the absence of TRPV1. H2O2 administration reduced TRPV1 expression in CMECs. HG-HF significantly depressed expression of PGC-1α (peroxisome proliferator-activated receptor-γ coactivator-1α) and OPA1 (optic atrophy 1) by reducing [Ca2+]i, whereas OPA1 supplementation partly reversed those detrimental effects induced by TRPV1-/- Furthermore, capsaicin treatment not only attenuated CMECs injury induced by HG-HF but also mitigated cardiac microvascular injury induced by T2DM. Collectively, T2DM leads to cardiac microvascular injury by exacerbating the vicious circle of TRPV1 blockage and reactive oxygen species overload. Long-term capsaicin can protect cardiac microvessels against T2DM via suppressing oxidative/nitrative stress mediated by TRPV1/Ca2+/PGC-1α/OPA1 pathway in CMECs.

Perimenopause vasomotor symptoms, coronary atherosclerosis and risk of myocardial infarction during menopause: the cardiologist's perspective

Myocardial infarction (MI) is rare in pre-menopausal women, and in most cases has a gender-specific pathogenesis. After menopause, MI incidence increases gradually to equalize men’s rate in the eighth decade of age, with similar pathogenesis. This epidemiological observation has raised a number of hypotheses on the protective effect of estrogen against atherosclerosis and its related diseases. However, MI has a multifactorial pathogenesis with variable contributions of inflammation, eroded or ruptured atherosclerotic plaques, vasoconstriction and thrombosis. Whether perimenopausal vasomotor symptoms are associated with a better, worse or neutral effect on the risk of myocardial infarction has long been disputed. The recent finding of the LADIES ACS study that women reporting transitional vasomotor symptoms have earlier onset myocardial infarction, as compared to women without symptoms, despite similar risk factors and extent of coronary angiographic disease, supports the hypothesis that endothelial dysfunction, or other vasoconstrictive mechanisms, may play a key role in precipitating an acute coronary syndrome at an earlier age. These factors, rather than other atherosclerotic markers, should be specifically investigated in order to elucidate the so far elusive link between vasomotor symptoms and risk of MI.

Inverse association of MRI-derived native myocardial T1 and perfusion reserve index in women with evidence of ischemia and no obstructive CAD: A pilot study

BACKGROUND

It has recently been shown that magnetic resonance (MR) "native T1" mapping is capable of characterizing abnormal microcirculation in patients with obstructive coronary artery disease (CAD). In studies involving women with signs and symptoms of ischemia and no obstructive CAD (INOCA), however, the potential role of native T1 as an imaging marker and its association with indices of diastolic function or vasodilator-induced myocardial ischemia have not been explored. We investigated whether native T1 in INOCA is associated with reduced myocardial perfusion reserve index (MPRI) or with diastolic dysfunction.

METHODS

Twenty-two female patients with INOCA and twelve female reference controls with matching age and body-mass index were studied. The patients had evidence of vasodilator-induced ischemia without obstructive CAD or any prior infarction. All 34 subjects underwent stress/rest MR including native T1 mapping (MOLLI 5(3)3) at 1.5-Tesla.

RESULTS

Compared with controls, patients had similar morphology/function. As expected, MPRI was significantly reduced in patients compared to controls (1.78 ± 0.39 vs. 2.49 ± 0.41, p < 0.0001). Native T1 was significantly elevated in patients (1040.1 ± 29.3 ms vs. 1003.8 ± 18.5 ms, p < 0.001) and the increased T1 showed a significant inverse correlation with MPRI (r = -0.481, p = 0.004), but was not correlated with reduced diastolic strain rate.

CONCLUSIONS

Symptomatic women with INOCA have elevated native T1 compared to matched reference controls and there is a significant association between elevated native T1 and impaired MPRI, considered a surrogate measure of ischemia severity in this cohort. Future studies in a larger cohort are needed to elucidate the mechanism underlying this inverse relationship.

Decreased coronary blood flow velocity in two patients with coronary microvascular spasm: case series†

Introduction

Diagnostic criteria for coronary microvascular spasm (CMS) have not yet been fully established.

Case presentation

We present two cases of CMS in which decreased coronary blood flow velocities were observed during acetylcholine (ACH) provocation tests. The first patient suffered from chest pain occurring while at rest. The patient underwent coronary angiography (CAG), which revealed a decrease in the average peak velocity (APV) from 29 cm/s to 14 cm/s and a slow flow phenomenon following ACH injection. The second patient suffered from chest pain occurring during the night. The patient underwent CAG, which revealed a decrease in the APV from 17 cm/s to 7 cm/s with no significant epicardial coronary artery spasm following ACH injection. Both patients complained of chest pain, and electrocardiogram changes were observed in leads equivalent to the distal area of the vessel during an ACH provocation test. These findings were consistent with CMS, and their conditions improved under medical treatment.

Discussion

A transient decrease in coronary blood flow velocity following ACH administration might be a phenomenon specific to CMS. These cases may provide some insight into the underlying pathophysiology of CMS.

Test Selection for Women with Suspected Stable Ischemic Heart Disease

Ischemic heart disease (IHD) is the leading cause of death and disability among women in the United States. Identifying IHD in women presenting with stable symptoms and stratifying their risk for an IHD event can be challenging for providers, with several different tests available. This article is meant to serve as a practical guide for clinicians treating women with potentially ischemic symptoms. Evidence and American Heart Association (AHA) recommendations regarding test selection are reviewed, with a focus on the information to be gained from each test. We outline suggested courses of action to be taken in the case of a positive or negative test. Regardless of the initial test result, clinicians should view a woman's symptom presentation as an opportunity to review and modify her risk of cardiovascular events.

Prevalence and characteristics of coronary microvascular dysfunction among chest pain patients in the emergency department

Aims:

Coronary microvascular dysfunction (CMD) is common in patients with non-obstructive coronary arteries but has not been described in low-risk symptomatic patients. We therefore assessed the prevalence and characteristics of CMD in low to moderate risk patients with chest pain in an emergency department.

Methods and results:

We used three-dimensional Rb82 cardiac positron emission tomography/computed tomography to diagnose coronary artery disease (known or new regional defect, any coronary calcification) and CMD (low coronary flow reserve without coronary artery disease) in chest pain patients after being ruled out for acute myocardial infarction. Exclusions included age 30 years or less, acute myocardial infarction, hemodynamic instability, heart failure and dialysis. Among 195 participants undergoing cardiac positron emission tomography/computed tomography, 42% had CMD, 36% had coronary artery disease and 22% had normal flows; 70% were women and 84% were obese. Patients with CMD and coronary artery disease had significantly lower coronary flow reserve than normal patients (mean coronary flow reserve 1.6 and 1.9 vs. 2.6, respectively, P<0.05). However, CMD patients were younger (mean age 51 vs. 61 years), and had fewer traditional cardiac risk factors ( P<0.05) than patients with coronary artery disease. Nearly one third (31%) of patients had a prior emergency department visit for chest pain within three years of index presentation. Women were four times as likely to have CMD as men (adjusted odds ratio 4.2; 95% confidence interval 1.8, 9.6) after controlling for age, race, hypertension, diabetes, smoking, dyslipidemia, obesity and family history of coronary artery disease.

Conclusions:

Despite their low-risk profile, nearly one half of symptomatic and mostly obese emergency department patients without evidence of myocardial infarction or coronary artery disease had CMD. The results could explain the high rates of return visits associated with chest pain, although their application to the general emergency department population require validation.

The role of imaging in women with ischemic heart disease

Substantial advances and insights in medical technology and treatment strategies, and the focus on sex-specific research have contributed to a reduction in cardiovascular mortality in women. Despite these advances, ischemic heart disease (IHD) remains the leading cause of cardiovascular morbidity and mortality of women in the Western world. Advances in cardiovascular imaging, over the past 4 decades, have significantly improved the evaluation and management of the full spectrum of coronary atherosclerosis, which contributes to ischemic heart disease. The development of contemporary and novel diagnostic imaging techniques and tools have assumed an expanded role in the evaluation of symptomatic women to detect not only flow-limiting epicardial coronary stenosis and nonobstructive atherosclerosis, but also ischemia resulting from microvascular dysfunction. IHD is now diagnosed early and with greater accuracy, leading to improved risk assessment and timely therapies in women. In this article, we review the available evidence on the role of contemporary diagnostic imaging techniques in the evaluation of women with suspected IHD.

Why names matter for women: MINOCA/INOCA (myocardial infarction/ischemia and no obstructive coronary artery disease)

The syndromes of myocardial infarction/myocardial ischemia with No Obstructive Coronary Artery Disease (MINOCA/INOCA) are increasingly evident. A majority of these patients have coronary microvascular dysfunction. These patients have elevated risk for a cardiovascular event (including acute coronary syndrome, myocardial infarction, stroke, and repeated cardiovascular procedures) and appear to be at higher risk for development of heart failure with preserved ejection fraction. Terminology such as coronary artery disease or coronary heart disease is often synonymous with obstructive atherosclerosis in the clinician's mind, leaving one at a loss to recognize or explain the phenomenon of MINOCA and INOCA with elevated risk. We review the available literature regarding stable and unstable ischemic heart disease that suggests that use of the ischemic heart disease (IHD) terminology matters for women, and should facilitate recognition of risk to provide potential treatment targets and optimized health.

Inter-scan Reproducibility of Cardiovascular Magnetic Resonance Imaging-Derived Myocardial Perfusion Reserve Index in Women with no Obstructive Coronary Artery Disease

BACKGROUND

Cardiovascular magnetic resonance imaging (CMRI) derived myocardial perfusion reserve index (MPRI) has recently been shown to detect coronary microvascular dysfunction (CMD) in women with signs and symptoms of ischemia and no obstructive coronary artery disease (CAD). The aim of this study was to determine the inter-scan reproducibility of MPRI in this patient group in order to assess its diagnostic robustness in serial scans and assess its utility as a marker of potential therapies for CMD.

METHODS

Rest/stress perfusion CMR was performed at 1.5T using a standardized protocol in 17 women with signs and symptoms of ischemia and no obstructive CAD on two separate days (within 90 days of each other). The same pharmacological stress agent (adenosine/regadenoson) was used for both scans. MPRI was calculated from time-intensity curves of the whole myocardium and blood pool at stress and rest. One experienced observer, blinded to clinical data, performed all measurements. Intra-class correlation coefficients (ICC), coefficient of variation (CoV), and Bland-Altman plots were determined.

RESULTS

Mean age was 53±10 years old and BMI 28±7 kg/m2; 47% had hypertension, 4% diabetes, 9% hyperlipidemia and 10% family history of CAD. Mean MPRI for the 17 women was higher for scan 2 compared to scan 1 (1.98±0.3 vs. 1.65±0.78, respectively, p<0.001); and this relationship persisted even when corrected for resting rate pressure product (RPP) (2.42±0.81 vs. 1.97±0.92, respectively, 0.002), The mean bias for MPRI between sequential scans was 0.34 (95% CI: 0.18 to 0.49, limits of agreement: -0.31, 0.98 and when corrected for resting RPP it was 0.45 (95% CI: 0.21 to 0.68, limits of agreement: -0.52, 1.41), ICC and CoV also indicated modest inter-scan reproducibility (ICC 0.57; CoV 20.3%), but both measures were comparable to values seen in prior studies in CAD populations and healthy volunteers.

CONCLUSION

Inter-scan reproducibility of CMRI-derived MPRI in women with suspected CMD is modest, with relatively wide limits of agreement. This variability is similar to that seen in other populations, suggesting that some caution must be exercised when using absolute MPRI cut-offs in isolation for the diagnosis of CMD or repeated measures of MPRI to track response to therapy. Additional work is ongoing to improve reproducibility from both biological and technological standpoints.

Quantitative cardiovascular magnetic resonance perfusion imaging identifies reduced flow reserve in microvascular coronary artery disease

BACKGROUND

Preliminary semi-quantitative cardiovascular magnetic resonance (CMR) perfusion studies have demonstrated reduced myocardial perfusion reserve (MPR) in patients with angina and risk factors for microvascular disease (MVD), however fully quantitative CMR has not been studied. The purpose of this study is to evaluate whether fully quantitative CMR identifies reduced MPR in this population, and to investigate the relationship between epicardial atherosclerosis, left ventricular hypertrophy (LVH), extracellular volume (ECV), and perfusion.

METHODS

Forty-six patients with typical angina and risk factors for MVD (females, or males with diabetes or metabolic syndrome) who had no obstructive coronary artery disease by coronary angiography and 20 healthy control subjects underwent regadenoson stress CMR perfusion imaging using a dual-sequence quantitative spiral pulse sequence to quantify MPR. Subjects also underwent T1 mapping to quantify ECV, and computed tomographic (CT) coronary calcium scoring to assess atherosclerosis burden.

RESULTS

In patients with risk factors for MVD, both MPR (2.21 [1.95,2.69] vs. 2.93 [2.763.19], p < 0.001) and stress myocardial perfusion (2.65 ± 0.62 ml/min/g, vs. 3.17 ± 0.49 ml/min/g p < 0.002) were reduced as compared to controls. These differences remained after adjusting for age, left ventricular (LV) mass, body mass index (BMI), and gender. There were no differences in native T1 or ECV between subjects and controls.

CONCLUSIONS

Stress myocardial perfusion and MPR as measured by fully quantitative CMR perfusion imaging are reduced in subjects with risk factors for MVD with no obstructive CAD as compared to healthy controls. Neither myocardial hypertrophy nor fibrosis accounts for these differences.

Advances in Cardiovascular Health in Women over the Past Decade: Guideline Recommendations for Practice

Cardiovascular disease (CVD) remains the number one cause of death in women. It is estimated that 44 million women in the United States are either living with or at risk for heart disease. This article highlights the recent significant progress made in improving care, clinical decision-making, and policy implications for women with CVD. We provide our perspective supported by evidence-based advances in cardiovascular research and clinical care guidelines in seven areas: (1) primary CVD prevention and community heart care, (2) secondary prevention of CVD, (3) stroke, (4) heart failure and cardiomyopathies, (5) ischemia with nonobstructive coronary artery disease, (6) spontaneous coronary artery dissection, and (7) arrhythmias and device therapies. Advances in these fields have improved the lives of women living with and at risk for heart disease. With increase awareness, partnership with national organizations, sex-specific research, and changes in policy, the morbidity and mortality of CVD in women can be further reduced.

Microvascular Coronary Dysfunction-an Overview

PURPOSE OF REVIEW

We will review the available data on the epidemiology, pathophysiology, diagnosis, and management of microvascular coronary dysfunction (MCD).

RECENT FINDINGS

The study of MCD was pioneered by the Women's Ischemia Syndrome Evaluation (WISE) cohort. New techniques in the diagnosis of this condition, using invasive and noninvasive means, are helping to increase awareness of this condition as well as ways in which to treat it. Microvascular coronary disease without epicardial involvement has become an increasingly recognized cause of cardiac chest pain, particularly in women. Dysfunction of the microvasculature related to endothelium-dependent and endothelial-independent factors likely results in symptoms and/or evidence of ischemia. Although there is a growing body of research, there is still much about MCD that we do not understand.

Design and Rationale for comParison Between ticagreLor and clopidogrEl on mIcrocirculation in Patients with Acute cOronary Syndrome Undergoing Percutaneous Coronary Intervention (PLEIO) Trial

It has been previously demonstrated that ticagrelor can reduce mortality compared to clopidogrel in acute coronary syndrome (ACS) patients. However, the mechanism for this mortality reduction remains uncertain. The objective of the present study is to assess the impact of chronic ticagrelor treatment on microvascular circulation. A total of 120 participants aged 20–85 years with clinical diagnosis of ACS will be randomized in a 1:1 fashion to the following two groups: ticagrelor 90 mg twice daily; clopidogrel 75 mg once daily. To evaluate the status of microcirculation, the primary end point is coronary microvascular dysfunction measured using an index of microcirculatory resistance (IMR) at 6 months after receiving the study agent. The purpose of this trial is to investigate whether ticagrelor, beyond its antiplatelet efficacy, could improve coronary microcirculation more effectively than clopidogrel for patients with ACS.

Mental stress peripheral vascular reactivity is elevated in women with coronary vascular dysfunction: Results from the NHLBI-sponsored Cardiac Autonomic Nervous System (CANS) study

BACKGROUND

Women with chest pain, ischemia, and no obstructive coronary artery disease often have coronary vascular dysfunction (CVaD). Peripheral vascular reactivity to mental stress may contribute mechanistic understanding of stress-induced ischemia in women with CVaD.

METHODS

62 women (41 CVaD and 21 controls) underwent mental stress testing (MST) with anger recall, mental arithmetic, and forehead cold pressor (COP) challenge. Emotional arousal was measured (Likert scale). Reactive hyperemia index (RHI) was calculated before and after MST by peripheral arterial tonometry (PAT). Stress PAT ratio (SPR) of pulse amplitude during stress to rest was obtained to measure vasoconstriction. Wilcoxson rank sum test was used for analysis.

RESULTS

Mean age of CVaD and control groups was 58±9 and 55±10years (p=0.73). Baseline RHI correlated with coronary endothelial function (r=0.36, p=0.03) and inversely with RHI change post-MST (r=-0.51, p<0.001). During MST, 10% of controls reported chest pain vs. 41% of CVaD subjects (p=0.01). RHI did not change significantly after MST in either group. CVaD subjects had lower SPR vs. controls during mental arithmetic (0.54 [0.15, 1.46] vs. 0.67 [0.36, 1.8], p=0.039), not evident in the other tasks. Vasoconstriction inversely correlated with anxiety (r=-3.4, p=0.03), frustration (r=-0.37, p=0.02), and feeling challenged (r=-0.37, p=0.02) in CVaD but not controls.

CONCLUSIONS

Mental stress peripheral vascular reactivity is elevated in women with CVaD compared to controls. Elevated vascular reactivity may be one contributor to stress-induced chest pain in CVaD. Interventions that modulate vasoconstrictive responses may be of benefit and should be tested in clinical trials in women with CVaD.

High-Sensitivity C-Reactive Protein Is a Predictor of Coronary Microvascular Dysfunction in Patients with Ischemic Heart Disease

Background

Inflammation and microvascular dysfunction (MVD) are independently associated with adverse cardiovascular outcomes in patients with ischemic heart disease. This study aimed to assess the relationship between inflammation, MVD, and myocardial injury.

Methods

Coronary microvascular function was assessed in 74 patients undergoing percutaneous coronary intervention (PCI) using the index of microvascular resistance (IMR) by a pressure–temperature sensor-tipped wire. Serum high-sensitivity C-reactive protein (hsCRP) level was quantified by rate turbidimetry. Severe MVD was defined as IMR ≥ 30. Pearson correlation was computed to assess the relationships between hsCRP, troponin, and IMR of culprit vessel. Predictors of severe MVD were assessed by regression analysis.

Results

Acute coronary syndromes (ACSs) represented 49% of the total cohort. Study cohort was divided into low C-reactive protein (CRP) (hsCRP < 3 mg/L) and high CRP (hsCRP ≥ 3 mg/L) groups. There was higher representation of smokers (78 vs. 52%), diabetics (39 vs. 18%), and ACS (61 vs. 33%), as well as higher body mass index (29.4 ± 4.6 vs. 27.2 ± 4.1) in the high CRP group. Pre-PCI and post-PCI IMR were significantly elevated in the high CRP group compared to the low CRP group (pre-PCI IMR: 29.0 ± 13.9 vs. 17.4 ± 11.1, p < 0.0001; post-PCI IMR: 23.0 ± 16.8 vs. 15.5 ± 8.4, p = 0.02). Peak troponin levels were significantly raised in the high CRP group (9.96 ± 17.19 vs. 1.17 ± 3.00 μg/L, p = 0.002). There was a strong positive correlation between hsCRP and pre-PCI IMR (r = 0.85, p < 0.0001). Pre- and post-PCI IMR levels were correlated with peak troponin level (r = 0.45, p < 0.0001; r = 0.33, p = 0.005, respectively). Predictors of severe MVD include male gender (OR 3.0), diabetes (OR 3.7), smoking history (OR 4.0), ACS presentation (OR 8.5), and hsCRP ≥ 3 mg/L (OR 5.6).

Conclusion

hsCRP is a significant predictor of MVD while MVD is associated with myocardial injury, supporting the central role of inflammation and MVD in the pathophysiology and complications of coronary artery disease.

Clinical Trial Registration

Australian New Zealand Clinical Trials Registry (ACTRN): 12617000648325. Universal Trial Number (UTN): U1111-1196-2246.

Discordance Between Fractional Flow Reserve and Coronary Flow Reserve: Insights From Intracoronary Imaging and Physiological Assessment

OBJECTIVES

The aim of this study was to investigate the epicardial and microvascular substrates associated with discordances between fractional flow reserve (FFR) and coronary flow reserve (CFR) values.

BACKGROUND

Discordances between FFR and CFR remain poorly characterized.

METHODS

FFR, hyperemic stenosis resistance (HSR), and intravascular ultrasound were performed as indexes of epicardial function and CFR and hyperemic microvascular resistance (HMR) as measures of microvascular function in 94 patients with moderate coronary stenosis. Maximal plaque burden (PB_max), HSR, and HMR were calculated in 4 quadrants based on values of FFR ≤0.80 and CFR ≤2.0 as follows: concordant normal (preserved FFR and CFR), concordant abnormal (low FFR and CFR), discordant low FFR and preserved CFR, and discordant preserved FFR and low CFR.

RESULTS

Sixty-four patients (68%) had concordant FFR and CFR findings, and 30 patients (32%) had discordant FFR and CFR. Compared with patients with preserved FFR and CFR, those with low FFR and CFR had higher PB_max (p = 0.003), higher HSR (p < 0.001), and similar HMR. Among patients with preserved FFR, those with reduced CFR had similar PB_max and HSR but a trend toward higher HMR (p = 0.058) compared with patients with preserved CFR. Among patients with reduced FFR, those with preserved CFR had lower PB_max (p = 0.004), a trend toward lower HSR (p = 0.065), and lower HMR (p = 0.03) compared with patients with reduced CFR. Furthermore, compared with patients with preserved FFR and low CFR, those with low FFR and preserved CFR had higher HSR (p = 0.022) but lower HMR (p = 0.003).

CONCLUSIONS

In patients with moderate coronary stenosis, preserved FFR and low CFR is associated with increased microvascular resistance, while low FFR and preserved CFR has modest epicardial stenosis and preserved microvascular function.

Sex Differences in the Coronary System

Cardiovascular disease remains the leading cause of morbidity and mortality for both women and men. Emerging evidence supports that ischemic heart disease (IHD) may manifest differently in women and men, in ways ranging from the clinical presentation, diagnosis, and management of disease to the basic biology and biomechanics of cardiomyocyte function and the coronary circulation. Women consistently present with a higher burden of symptoms and comorbidities as compared with men and experience worse outcomes. These data have proved perplexing given the decreased likelihood of women to demonstrate obstructive coronary artery disease (CAD) on coronary angiography. Reported sex differences have long been influenced by the practice of defining heart disease primarily as obstructive CAD, but obstructive plaque is now recognized as neither necessary nor sufficient to explain symptoms of IHD, and it is no longer adequate to tailor diagnostic and treatment strategies only to this subset of patients. To date, women remain underrepresented in guideline-changing heart disease research and trials, creating important limitations in the evidence base for cardiovascular medicine. Smaller epicardial coronary arteries in women as compared to men, coupled with differences in shear stress and inflammatory mediators over the life span, may modify the development of CAD in susceptible patients into a diffuse pattern with more contribution from coronary vasomotor dysfunction than focal obstruction. Newer studies corroborate that symptomatic women are more likely than men to present with nonobstructive CAD and coronary microvascular dysfunction. When present, these processes increase cardiovascular risk in both women and men but may constitute an especially malignant phenotype in a subset of severely affected women, with implications for the management of not only CAD but also heart failure with preserved ejection fraction. This represents a state-of-the-art review of sex differences in the coronary system, with an eye toward how diverse pathophysiological processes may contribute to IHD phenotypes prevalent in women and men. Beyond providing women and men with equitable optimal care according to current paradigms, understanding the pathophysiology of IHD beyond a conventional focus on obstructive CAD is needed to address what is likely a combination of biological as well as environmental determinants of their prognosis.

Unsettled Issues and Future Directions for Research on Cardiovascular Diseases in Women

Biological sex (being female or male) significantly influences the course of disease. This simple fact must be considered in all cardiovascular diagnosis and therapy. However, major gaps in knowledge about and awareness of cardiovascular disease in women still impede the implementation of sex-specific strategies. Among the gaps are a lack of understanding of the pathophysiology of women-biased coronary artery disease syndromes (spasms, dissections, Takotsubo syndrome), sex differences in cardiomyopathies and heart failure, a higher prevalence of cardiomyopathies with sarcomeric mutations in men, a higher prevalence of heart failure with preserved ejection fraction in women, and sex-specific disease mechanisms, as well as sex differences in sudden cardiac arrest and long QT syndrome. Basic research strategies must do more to include female-specific aspects of disease such as the genetic imbalance of 2 versus one X chromosome and the effects of sex hormones. Drug therapy in women also needs more attention. Furthermore, pregnancy-associated cardiovascular disease must be considered a potential risk factor in women, including pregnancy-related coronary artery dissection, preeclampsia, and peripartum cardiomyopathy. Finally, the sociocultural dimension of gender should be included in research efforts. The organization of gender medicine must be established as a cross-sectional discipline but also as a centered structure with its own research resources, methods, and questions.

Sex Differences in Hemodynamic and Microvascular Mechanisms of Myocardial Ischemia Induced by Mental Stress

OBJECTIVE

To investigate sex-specific vascular mechanisms for mental stress-induced myocardial ischemia (MSIMI).

APPROACH AND RESULTS

Baseline data from a prospective cohort study of 678 patients with coronary artery disease underwent myocardial perfusion imaging before and during a public speaking stressor. The rate-pressure product response was calculated as the difference between the maximum value during the speech minus the minimum value during rest. Peripheral vasoconstriction by peripheral arterial tonometry was calculated as the ratio of pulse wave amplitude during the speech over the resting baseline; ratios <1 indicate a vasoconstrictive response. MSIMI was defined as percent of left ventricle that was ischemic and as a dichotomous variable. Men (but not women) with MSIMI had a higher rate-pressure product response than those without MSIMI (6500 versus 4800 mm Hg bpm), whereas women (but not men) with MSIMI had a significantly lower peripheral arterial tonometry ratio than those without MSIMI (0.5 versus 0.8). In adjusted linear regression, each 1000-U increase in rate-pressure product response was associated with 0.32% (95% confidence interval, 0.22-0.42) increase in inducible ischemia among men, whereas each 0.10-U decrease in peripheral arterial tonometry ratio was associated with 0.23% (95% confidence interval, 0.11-0.35) increase in inducible myocardial ischemia among women. Results were independent of conventional stress-induced myocardial ischemia.

CONCLUSIONS

Women and men have distinct cardiovascular reactivity mechanisms for MSIMI. For women, stress-induced peripheral vasoconstriction with mental stress, and not increased hemodynamic workload, is associated with MSIMI, whereas for men, it is the opposite. Future studies should examine these pathways on long-term outcomes.

Daily Activity Measured With Wearable Technology as a Novel Measurement of Treatment Effect in Patients With Coronary Microvascular Dysfunction: Substudy of a Randomized Controlled Crossover Trial

BACKGROUND

Digital wearable devices provide a "real-world" assessment of physical activity and quantify intervention-related changes in clinical trials. However, the value of digital wearable device-recorded physical activity as a clinical trial outcome is unknown.

OBJECTIVE

Because late sodium channel inhibition (ranolazine) improves stress laboratory exercise duration among angina patients, we proposed that this benefit could be quantified and translated during daily life by measuring digital wearable device-determined step count in a clinical trial.

METHODS

We conducted a substudy in a randomized, double-blinded, placebo-controlled, crossover trial of participants with angina and coronary microvascular dysfunction (CMD) with no obstructive coronary artery disease to evaluate the value of digital wearable device monitoring. Ranolazine or placebo were administered (500-1000 mg twice a day) for 2 weeks with a subsequent 2-week washout followed by crossover to ranolazine or placebo (500-1000 mg twice a day) for an additional 2 weeks. The outcome of interest was within-subject difference in Fitbit Flex daily step count during week 2 of ranolazine versus placebo during each treatment period. Secondary outcomes included within-subject differences in angina, quality of life, myocardial perfusion reserve, and diastolic function.

RESULTS

A total of 43 participants were enrolled in the substudy and 30 successfully completed the substudy for analysis. Overall, late sodium channel inhibition reduced within-subject daily step count versus placebo (mean 5757 [SD 3076] vs mean 6593 [SD 339], P=.01) but did not improve angina (Seattle Angina Questionnaire-7 [SAQ-7]) (P=.83). Among the subgroup with improved angina (SAQ-7), a direct correlation with increased step count (r=.42, P=.02) was observed.

CONCLUSIONS

We report one of the first studies to use digital wearable device-determined step count as an outcome variable in a placebo-controlled crossover trial of late sodium channel inhibition in participants with CMD. Our substudy demonstrates that late sodium channel inhibition was associated with a decreased step count overall, although the subgroup with angina improvement had a step count increase. Our findings suggest digital wearable device technology may provide new insights in clinical trial research.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01342029; https://clinicaltrials.gov/ct2/show/NCT01342029 (Archived by WebCite at http://www.webcitation.org/6uyd6B2PO).

The prognostic value of asymmetric dimethylarginine in patients with cardiac syndrome X

Background

The pathophysiology of cardiac syndrome X is multifactorial and endothelial dysfunction has been implicated as important contributing factor. Asymmetric dimethylarginine (ADMA), characterized as a circulating endogenous inhibitor of nitric oxide synthase, may have been implicated as an important contributing factor for the development of endothelial dysfunction. In this study, we aim to assess the predictive power of ADMA for long-term prognosis in patients with cardiac syndrome X.

Methods and results

We enrolled 239 consecutive patients with cardiac syndrome X diagnosed by coronary angiography. The mean age was 58.7±10.1 years. The patients were grouped into tertiles according to the plasma ADMA levels: <0.38 μmol/l (tertile I), 0.38–0.44 μmol/l (tertile II), and >0.44 μmol/l (tertile III). All patients were followed up for a mean period of 6.5±1.5 years (median: 6.3 years, inter-quartile range: 5.7–8.0 years). During the follow-up period, major adverse events (MAE) were observed in 15 patients (6.3%), including 13 deaths. The plasma ADMA levels in patients who developed MAE were significantly higher than those who did not (0.48±0.06 μmol/l vs. 0.42±0.08 μmol/l, p = 0.005). In multivariate Cox regression analysis adjusted for age, eGFR and LVEF, ADMA tertile I and II were identify to be associated with a significantly lower risk of MAE compared to ADMA tertile III (p = 0.017). By considering the plasma ADMA level as a continuous variable, the plasma ADMA level remained a significant independent predictor for outcomes of MAE, and the relative risk of MACE increased by 50% when plasma ADMA level increased by 1 SD of value (p = 0.018).

Conclusions

In patients with cardiac syndrome X, elevated plasma ADMA levels appeared to be an independent predictor of long-term adverse clinical outcomes.

Assessing Coronary Blood Flow Physiology in the Cardiac Catheterisation Laboratory

Background:

Contemporary management of coronary disease focuses on the treatment of stenoses in the major epicardial vessels. However, myocardial blood flow is known to be contingent on a range of factors in addition to the patency of the epicardial vessels. These include anatomical and physiological factors such as the extent of myocardium supplied by the vessel, systemic blood pres-sure, the natural variation in vascular tone in response to physiological needs which allows for coro-nary autoregulation and pathological factors such as the presence of downstream obstruction to flow due to disease of the small coronary vessels or myocardium. The assessment of clinical effectiveness and adequacy of coronary revascularisation requires the ability to comprehensively and accurately as-sess and measure myocardial perfusion.

Conclusion:

In this article, we review the current methods of evaluating coronary blood flow and my-ocardial perfusion in the cardiac catheterisation laboratory.

Sex-Related Differences in Vasomotor Function in Patients With Angina and Unobstructed Coronary Arteries

BACKGROUND

Coronary vasomotor dysfunction is an important mechanism for angina in patients with unobstructed coronary arteries.

OBJECTIVES

The purpose of this study was to determine sex differences in the prevalence and clinical presentation of vasomotor dysfunction in a European population and to examine sex differences in the dose of acetylcholine leading to a positive acetylcholine provocation test (ACH test).

METHODS

Between 2007 and 2014, we included 1,379 consecutive patients with stable angina, unobstructed coronaries and ACH test performed for epicardial vasospasm or coronary microvascular dysfunction (CMD) due to microvascular spasm. The predictive value of sex, risk factors, symptoms, and noninvasive test results was analyzed by means of logistic regression.

RESULTS

The mean patient age was 62 years, and 42% were male. There were 813 patients (59%) with a pathological ACH test, 33% for CMD and 26% for epicardial vasospasm. A pathological test was more common in females (70% vs. 43%; p < 0.001). In a multivariable logistic regression model the sex difference was statistically significant with a female-male odds ratio for CMD and epicardial vasospasm of 4.2 (95% confidence interval: 3.1 to 5.5; p < 0.001) and 2.3 (95% confidence interval: 1.7 to 3.1; p < 0.001), respectively. Effort-related symptoms, but neither risk factors nor noninvasive stress tests, contributed to predicting a pathological test. Female patients were more sensitive to acetylcholine with vasomotor dysfunction occurring at lower ACH doses compared with male patients.

CONCLUSIONS

Vasomotor dysfunction is frequent in patients with angina and unobstructed coronaries in a European population. Female patients have a higher prevalence of vasomotor dysfunction (especially CMD) compared with male patients. A pathological ACH test was observed at lower ACH doses in women compared with men.

Ventricular repolarization alterations in women with angina pectoris and suspected coronary microvascular dysfunction

OBJECTIVES

CMD could be the explanation of angina pectoris with no obstructive CAD and may cause ventricular repolarization changes. We compared T-wave morphology and QTc interval in women with angina pectoris with a control group as well as the associations with CMD.

METHODS

Women with angina pectoris and no obstructive coronary artery disease (n=138) and age-matched controls were compared in regard to QTc interval and morphology combination score (MCS) based on T-wave asymmetry, flatness and presence of T-wave notch. CMD was assessed as a coronary flow velocity reserve (CFVR) by transthoracic echocardiography.

RESULTS

Women with angina pectoris had significantly longer QTc intervals (429±20ms) and increased MCS (IQR) (0.73 [0.64-0.80]) compared with the controls (419±20ms) and (0.63 [(0.53-0.73]), respectively (both p<0.001). CFVR was associated with longer QTc interval (p=0.02), but the association was attenuated after multivariable adjustment (p=0.08).

CONCLUSION

This study suggests that women with angina pectoris have alterations in T-wave morphology as well as longer QTc interval compared with a reference population. CMD might be an explanation.

Preeclampsia and cardiovascular disease: interconnected paths that enable detection of the subclinical stages of obstetric and cardiovascular diseases

The potent and now longstanding evidence of the association between placentation-related disorders and cardiovascular disease should be translated into clinical practice in order to introduce a preventive approach to future obstetric and cardiovascular diseases. The purpose of this review is to integrate cardiovascular risk/disease and obstetric complications, which are linked by endothelial dysfunction, as windows of opportunity for improving women's health. Questionnaires adaptable to local practices are proposed to incorporate cardiovascular and obstetrical indexes into two stages of a woman's lifetime.

Sudden Cardiac Death in Women With Suspected Ischemic Heart Disease, Preserved Ejection Fraction, and No Obstructive Coronary Artery Disease: A Report From the Women's Ischemia Syndrome Evaluation Study

Background

Sudden cardiac death (SCD) is often the first presentation of ischemic heart disease; however, there is limited information on SCD among women with and without obstructive coronary artery disease (CAD). We evaluated SCD incidence in the WISE (Women's Ischemia Syndrome Evaluation) study.

Methods and Results

Overall, 904 women with suspected ischemic heart disease with preserved ejection fraction and core laboratory coronary angiography were followed for outcomes. In case of death, a death certificate and/or a physician or family narrative of the circumstances of death was obtained. A clinical events committee rated all deaths as cardiovascular or noncardiovascular and as SCD or non‐SCD. In total, 96 women (11%) died over a median of 6 years (maximum: 8 years). Among 65 cardiovascular deaths, 42% were SCD. Mortality per 1000 person‐hours increased linearly with CAD severity (no CAD: 5.8; minimal: 15.9; obstructive: 38.6; P<0.0001). However, the proportion of SCD was similar across CAD severity: 40%, 58%, and 38% for no, minimal, and obstructive CAD subgroups, respectively (P value not significant). In addition to traditional risk factors (age, diabetes mellitus, smoking), a history of depression (P=0.018) and longer corrected QT interval (P=0.023) were independent SCD predictors in the entire cohort. Corrected QT interval was an independent predictor of SCD in women without obstructive CAD (P=0.033).

Conclusions

SCD contributes substantially to mortality in women with and without obstructive CAD. Corrected QT interval is the single independent SCD risk factor in women without obstructive CAD. In addition to management of traditional risk factors, these data indicate that further investigation should address mechanistic understanding and interventions targeting depression and corrected QT interval in women.

Quantitative Assessment of Coronary Microvascular Function: Dynamic Single-Photon Emission Computed Tomography, Positron Emission Tomography, Ultrasound, Computed Tomography, and Magnetic Resonance Imaging

A healthy, functional microcirculation in combination with nonobstructed epicardial coronary arteries is the prerequisite of normal myocardial perfusion. Quantitative assessment in myocardial perfusion and determination of absolute myocardial blood flow can be achieved noninvasively using dynamic imaging with multiple imaging modalities. Extensive evidence supports the clinical value of noninvasively assessing indices of coronary flow for diagnosing coronary microvascular dysfunction; in certain diseases, the degree of coronary microvascular impairment carries important prognostic relevance. Although, currently positron emission tomography is the most commonly used tool for the quantification of myocardial blood flow, other modalities, including single-photon emission computed tomography, computed tomography, magnetic resonance imaging, and myocardial contrast echocardiography, have emerged as techniques with great promise for determination of coronary microvascular dysfunction. The following review will describe basic concepts of coronary and microvascular physiology, review available modalities for dynamic imaging for quantitative assessment of coronary perfusion and myocardial blood flow, and discuss their application in distinct forms of coronary microvascular dysfunction.