Coronary Microvascular Dysfunction in Patients With Systemic Lupus Erythematosus and Chest Pain

Expanding landscape of coronary microvascular disease in co-morbid conditions: Metabolic disease and beyond

Coronary microvascular disease (CMD) and impaired coronary blood flow control are defects that occur early in the pathogenesis of heart failure in cardiometabolic conditions, prior to the onset of atherosclerosis. In fact, recent studies have shown that CMD is an independent predictor of cardiac morbidity and mortality in patients with obesity and metabolic disease. CMD is comprised of functional, structural, and mechanical impairments that synergize and ultimately reduce coronary blood flow in metabolic disease and in other co-morbid conditions, including transplant, autoimmune disorders, chemotherapy-induced cardiotoxicity, and remote injury-induced CMD. This review summarizes the contemporary state-of-the-field related to CMD in metabolic and these other co-morbid conditions based on mechanistic data derived mostly from preclinical small- and large-animal models in light of available clinical evidence and given the limitations of studying these mechanisms in humans. In addition, we also discuss gaps in current understanding, emerging areas of interest, and opportunities for future investigations in this field.

RNAseq of INOCA patients identifies innate, invariant, and acquired immune changes: potential autoimmune microvascular dysfunction

Background

Ischemia with non-obstructive coronary arteries (INOCA) is a major clinical entity that involves potentially 20%-30% of patients with chest pain. INOCA is typically attributed either to coronary microvascular disease and/or vasospasm, but is likely distinct from classical coronary artery disease (CAD).

Objectives

To gain insights into the etiology of INOCA and CAD, RNA sequencing of whole blood from patients undergoing both stress testing and elective invasive coronary angiography (ICA) was conducted.

Methods

Stress testing and ICA of 177 patients identified 40 patients (23%) with INOCA compared to 39 controls (stress-, ICA-). ICA+ patients divided into 38 stress- and 60 stress+. RNAseq was performed by Illumina with ribosomal RNA depletion. Transcriptome changes were analyzed by DeSeq2 and curated by manual and automated methods.

Results

Differentially expressed genes for INOCA were associated with elevated levels of transcripts related to mucosal-associated invariant T (MAIT) cells, plasmacytoid dendritic cells (pcDC), and memory B cells, and were associated with autoimmune diseases such as rheumatoid arthritis. Decreased transcripts were associated with neutrophils, but neutrophil transcripts, per se, were not less abundant in INOCA. CAD transcripts were more related to T cell functions.

Conclusions

Elevated transcripts related to pcDC, MAIT, and memory B cells suggest an autoimmune component to INOCA. Reduced neutrophil transcripts are likely attributed to chronic activation leading to increased translation and degradation. Thus, INOCA could result from stimulation of B cell, pcDC, invariant T cell, and neutrophil activation that compromises cardiac microvascular function.

Alterations in genes associated with cytosolic RNA sensing in whole blood are associated with coronary microvascular disease in SLE

Systemic lupus erythematosus (SLE) patients are 90% women and over three times more likely to die of cardiovascular disease than women in the general population. Chest pain with no obstructive cardiac disease is associated with coronary microvascular disease (CMD), where narrowing of the small blood vessels can lead to ischemia, and frequently reported by SLE patients. Using whole blood RNA samples, we asked whether gene signatures discriminate SLE patients with coronary microvascular dysfunction (CMD) on cardiac MRI (n=4) from those without (n=7) and whether any signaling pathway is linked to the underlying pathobiology of SLE CMD. RNA-seq analysis revealed 143 differentially expressed (DE) genes between the SLE and healthy control (HC) groups, with virus defense and interferon (IFN) signaling being the key pathways identified as enriched in SLE as expected. We next conducted a comparative analysis of genes differentially expressed in SLE-CMD and SLE-non-CMD relative to HC samples. Our analysis highlighted differences in IFN signaling, RNA sensing and ADP-ribosylation pathways between SLE-CMD and SLE-non-CMD. This is the first study to investigate possible gene signatures associating with CMD in SLE, and our data strongly suggests that distinct molecular mechanisms underly vascular changes in CMD and non-CMD involvement in SLE.

Reduced Left Ventricular Function on Cardiac MRI in SLE Patients Correlates with Measures of SLE Disease Activity and Inflammation

Background

Women with SLE have an elevated risk of CVD morbidity and mortality and frequently report chest pain in the absence of obstructive CAD. Echocardiographic studies often demonstrate reduced LV function, correlating with higher disease activity. We used cardiac MRI (cMRI) to investigate the relationship between SLE, related inflammatory biomarkers and cardiac function in female SLE patients.

Methods

Women with SLE reporting chest pain with no obstructive CAD (n=13) and reference controls (n=22) were evaluated using stress-rest cMRI to measure LV structure, function, tissue characteristics, and myocardial perfusion reserve index (MPRI). Coronary microvascular dysfunction (CMD) was defined as MPRI <1.84. Serum samples were analyzed for inflammatory markers. Relationships between clinical and cMRI values of SLE subjects were assessed, and groups were compared.

Results

40% of SLE subjects had MPRI < 1.84 on cMRI. Compared to controls, SLE subjects had higher LV volumes and mass and lower LV systolic function. SLICC DI was related to worse cardiac function and higher T1. CRP was related to higher cardiac output and a trend to better systolic function, while ESR and fasting insulin were related to lower LV mass. Lower fasting insulin levels correlated with increased ECV.

Conclusions

Among our female SLE cohort, 40% had CMD, and SLICC DI correlated with worse cardiac function and diffuse fibrosis. Higher inflammatory markers and low insulin levels may associate with LV dysfunction. Our findings underline the potential of non-invasive cMRI as a tool for monitoring cardiovascular function in SLE patients.

Atherosclerosis in Systemic Lupus Erythematosus

PURPOSE OF THE REVIEW

Systemic lupus erythematosus (SLE) patients are at increased risk of cardiovascular disease (CVD) compared to the general population, despite most patients being young females, who are not classically considered to be at high risk for cardiovascular disease using traditional risk assessment tools. The purpose of this review is to discuss the pathophysiology of atherosclerosis in SLE and raise awareness of the relationship between SLE and CVD.

RECENT FINDINGS

The increased risk of CVD in SLE patients is multifactorial, due to proatherogenic lipid profiles, immune dysregulation and inflammation, side effects of lupus treatment, and microvascular dysfunction. Conventional CV risk models often underperform in the identification of SLE patients at high risk of atherosclerosis. The use of non-invasive imaging serves as a strategy to identify patients with evidence of subclinical CVD and in the evaluation of symptomatic patients. Identification of subclinical atherosclerosis allows for aggressive management of CV risk factors. SLE patients experience an increased risk of atherosclerotic CVD, which is not solely explained by traditional CV risk factors. It is imperative that clinicians are aware of this association to implement prompt detection and treatment of atherosclerotic CVD in SLE patients.

The importance of microvascular inflammation in ageing and age-related diseases: a position paper from the ESH working group on small arteries, section of microvascular inflammation

Microcirculation is pervasive and orchestrates a profound regulatory cross-talk with the surrounding tissue and organs. Similarly, it is one of the earliest biological systems targeted by environmental stressors and consequently involved in the development and progression of ageing and age-related disease. Microvascular dysfunction, if not targeted, leads to a steady derangement of the phenotype, which cumulates comorbidities and eventually results in a nonrescuable, very high-cardiovascular risk. Along the broad spectrum of pathologies, both shared and distinct molecular pathways and pathophysiological alteration are involved in the disruption of microvascular homeostasis, all pointing to microvascular inflammation as the putative primary culprit. This position paper explores the presence and the detrimental contribution of microvascular inflammation across the whole spectrum of chronic age-related diseases, which characterise the 21st-century healthcare landscape. The manuscript aims to strongly affirm the centrality of microvascular inflammation by recapitulating the current evidence and providing a clear synoptic view of the whole cardiometabolic derangement. Indeed, there is an urgent need for further mechanistic exploration to identify clear, very early or disease-specific molecular targets to provide an effective therapeutic strategy against the otherwise unstoppable rising prevalence of age-related diseases.

Reduced left ventricular function on cardiac MRI of SLE patients correlates with measures of disease activity and inflammation

Background

Women with SLE have an elevated risk of cardiovascular disease. Many women with SLE frequently report chest pain in the absence of obstructive coronary artery disease (CAD) due to coronary microvascular dysfunction (CMD), a form of ischemia with no obstructive CAD. Echocardiographic studies have shown that SLE patients have reduced left ventricular (LV) function, which may also correlate with higher SLE disease activity scores. As such, we used cardiac magnetic resonance imaging (cMRI) to investigate the relationship between SLE, related inflammatory biomarkers, and cardiac function in female SLE patients.

Methods

We performed stress cMRI in women with SLE and chest pain with no obstructive CAD (n=13, all met ACR 1997 criteria,) and reference controls (n=22) using our published protocol. We evaluated LV function, tissue characterization (T1 mapping, ECV), and delayed enhancement, using CV142 software (Circle Cardiovascular Imaging Inc, Calgary, AB, Canada). Myocardial perfusion reserve index (MPRI) was calculated using our published protocol. SLEDAI and SLICC Damage Index (DI) were calculated per validated criteria. Serum samples were analyzed for inflammatory markers and autoantibodies. Wilcoxon rank-sum test was performed on clinical values with CMD and no CMD SLE subjects, and on cMRI values with all SLE subjects and controls. Correlation analysis was done on clinical values, and cMRI values on all SLE subjects.

Results

Overall, 40% of SLE subjects had MPRI values < 1.84, consistent with CMD. Compared to controls, SLE subjects had significantly lower LVEF, and higher LVESVi and LVMi. Corresponding to this, radial, longitudinal, and circumferential strain were significantly lower in the SLE subjects. In correlation analysis of serum inflammatory biomarkers to cMRI values in the SLE subjects, SLICC DI was related to worse cardiac function (lower radial, circumferential and longitudinal strain) and higher T1 time. Additionally, fasting insulin and ESR were negatively correlated with LVMi. Fasting insulin also negatively correlated with ECV. CRP had a positive association with LVESV index and CI and a negative association with longitudinal strain.

Conclusions

Among women with SLE with chest pain and no obstructive CAD, 40% have CMD. While evaluations of known inflammatory markers (such as CRP and ESR) predictably correlated with decreased cardiac function, our study found that decreased fasting insulin levels as a novel marker of diminished LV function. In addition, low insulin levels were observed to correlate with increased LVMi and ECV, suggesting a cardioprotective effect of insulin in SLE patients. We also noted that SLICC DI, an assessment of SLE damage, correlates with cardiac dysfunction in SLE. Our findings underline the potential of non-invasive cMRI as a tool for monitoring cardiovascular function in SLE, particularly in patients with high SLICC DI, ESR and CRP and low fasting insulin levels.

Autoimmune rheumatic diseases in women with coronary microvascular dysfunction: a report from the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD) project

Background

While autoimmune rheumatic diseases (ARDs) have been linked with coronary microvascular dysfunction (CMD), the relationship between ARD and CMD in women with signs and symptoms of ischemia and no obstructive arteries (INOCA) are not well described. We hypothesized that among women with CMD, those with ARD history have greater angina, functional limitations, and myocardial perfusion compromise compared to those without ARD history.

Methods

Women with INOCA and confirmed CMD by invasive coronary function testing were included from the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD) project (NCT00832702). Seattle Angina Questionnaire (SAQ), Duke Activity Status Index (DASI), and cardiac magnetic resonance myocardial perfusion reserve index (MPRI) were collected at baseline. Chart review was performed to confirm self-reported ARD diagnosis.

Results

Of the 207 women with CMD, 19 (9%) had a confirmed history of ARD. Compared to those without ARD, women with ARD were younger (p = 0.04). In addition, they had lower DASI-estimated metabolic equivalents (p = 0.03) and lower MPRI (p = 0.008) but similar SAQ scores. There was a trend towards increased nocturnal angina and stress-induced angina in those with ARD (p = 0.05 for both). Invasive coronary function variables were not significantly different between groups.

Conclusions

Among women with CMD, women with a history of ARD had lower functional status and worse myocardial perfusion reserve compared to women without ARD. Angina-related health status and invasive coronary function were not significantly different between groups. Further studies are warranted to understand mechanisms contributing to CMD among women with ARDs with INOCA.

Qualitative and Quantitative Stress Perfusion Cardiac Magnetic Resonance in Clinical Practice: A Comprehensive Review

Stress cardiovascular magnetic resonance (CMR) imaging is a well-validated non-invasive stress test to diagnose significant coronary artery disease (CAD), with higher diagnostic accuracy than other common functional imaging modalities. One-stop assessment of myocardial ischemia, cardiac function, and myocardial viability qualitatively and quantitatively has been proven to be a cost-effective method in clinical practice for CAD evaluation. Beyond diagnosis, stress CMR also provides prognostic information and guides coronary revascularisation. In addition to CAD, there is a large body of literature demonstrating CMR's diagnostic performance and prognostic value in other common cardiovascular diseases (CVDs), especially coronary microvascular dysfunction (CMD). This review focuses on the clinical applications of stress CMR, including stress CMR scanning methods, practical interpretation of stress CMR images, and clinical utility of stress CMR in a setting of CVDs with possible myocardial ischemia.

Critical role of the coronary microvasculature in heart disease: From pathologic driving force to "innocent" bystander

The coronary microvasculature is responsible for providing oxygen and nutrients to myocardial tissue. A healthy microvasculature with an intact and properly functioning endothelium accomplishes this by seemless changes in vascular tone to match supply and demand. Perturbations in the normal physiology of the microvasculature, including endothelial and/or vascular smooth muscle dysfunction, result in impaired function (vasoconstriction, antithrombotic, etc.) and structural (hypertrophic, fibrotic) abnormalities that lead to microvascular ischemia and potential organ damage. While coronary microvascular dysfunction (CMD) is the primary pathologic driving force in ischemia with non-obstructive coronary artery disease (INOCA), angina with no obstructive coronary arteries (ANOCA), and myocardial infarction with non-obstructed coronary arteries (MINOCA), it may be a bystander in many cardiac disorders which later become pathologically associated with signs and/or symptoms of myocardial ischemia. Importantly, regardless of the primary or secondary basis of CMD in the heart, it is associated with important increases in morbidity and mortality. In this review we discuss salient features pertaining to known pathophysiologic mechanisms driving CMD, the spectrum of heart diseases where it places a critical role, invasive and non-invasive diagnostic testing, management strategies, and the gaps in knowledge where future research efforts are needed.