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

The performance of angiography-derived index of microcirculatory resistance for ischemia in angina with non-obstructive coronary artery disease: Validated by wire-based IMR and SPECT-MPI

BACKGROUND

Coronary microvascular dysfunction (CMD) accounts for a significant part of angina with non-obstructive coronary artery (ANOCA). Angiography-derived index of microcirculatory resistance (angio-IMR) has been developed for the evaluation of CMD but not yet validated sufficiently in ANOCA.

AIMS

To validate angio-IMR against wire-based IMR and to investigate its diagnostic performance for ischemia in ANOCA patients.

METHODS

This study included two independent cohorts. The angio-IMR and wire-based IMR were measured in 74 patients (74 vessels) in the wire-based IMR validation cohort. The angio-IMR and single-photon emission computed tomography-myocardial perfusion imaging (SPECT-MPI) were successfully completed in 136 patients (408 vessels) in the SPECT-MPI validation cohort. The ischemia was defined as the myocardial perfusion defect on SPECT-MPI and a summed difference score (SDS) ≥ 2.

RESULTS

In the wire-based IMR validation cohort, the angio-IMR ≥ 25 had the high diagnostic efficiency (area under the receiver-operating characteristics curve (AUC): 0.917, 95 %CI: 0.843-0.922; p < 0.001) and classification agreement (CA) (91.9 %) with the referenced wire-based IMR ≥ 25. In the SPECT-MPI validation cohort, more ischemia was observed in the high angio-IMR group (angio-IMR ≥ 25) compared to the low angio-IMR group (angio-IMR < 25) (55.2 % vs 10.4 %, p < 0.001). The angio-IMR ≥ 25 had a moderate diagnostic performance for ischemia (AUC: 0.759, 95 %CI: 0.670-0.849; p < 0.001), and it could improve the ability to discriminate ischemia in ANOAC patients (integrated discrimination improvement (IDI): 0.184; p < 0.001; net reclassification improvement (NRI): 0.217; p < 0.001).

CONCLUSION

The study demonstrates that angio-IMR, validated through both wire-based IMR and SPECT-MPI, presents a promising and convenient diagnostic approach for identifying ischemia in patients with ANOCA.

Coronary microvascular dysfunction and its role in heart failure with preserved ejection fraction for future prevention and treatment

Ischemic heart disease has long been established as the leading cause of heart failure, typically as a result of hemodynamically significant and obstructive coronary anatomy. Since, the role of dysfunctional coronary microvascular pathophysiologic mechanisms have also been associated with the development of congestive heart failure (CHF), most notably heart failure with preserved ejection fraction (HFpEF) although with limited clinical evidence. Conventional cardiometabolic and behavioral risk factors common to HFpEF such as diabetes mellitus (DM), obesity, hypertension, dyslipidemia, smoking, and chronic kidney disease foster a pro-inflammatory environment conducive to endothelial dysfunction and improper regulation of vasoactive substances. The impaired relaxation and increased vasoconstriction of damaged endothelium gives rise to impaired coronary blood flow and episodes of transient ischemia. Such coronary microvascular dysfunction (CMD) has its own implication on cardiovascular pathophysiologic mechanisms beyond symptomatic coronary and myocardial ischemia, and thus its own potential prevention goals and treatment targets for patients with HFpEF, where previous management had been limited. As such, we conducted a literature review to address the current landscape of data which links CMD to HFpEF. Furthermore, we considered the implications of biopsychosocial elements such as race, ethnicity, sex, gender, and the social determinants of health as they relate to the disparate health outcomes of those most at risk for CMD and HFpEF.

Rationale and design of the women's ischemia syndrome evaluation mechanisms of coronary microvascular dysfunction leading to preheart failure with preserved ejection fraction (WISE Pre-HFPEF)

BACKGROUND

There is increasing recognition that the pathophysiology of coronary microvascular dysfunction (CMD) plays a pivotal role in the development of heart failure with preserved ejection fraction (HFpEF). However, the mechanisms underlying this role are not known.

STUDY DESIGN AND METHODS

The Women's Ischemia Syndrome Evaluation Mechanisms of Coronary Microvascular Dysfunction Leading to Pre-Heart Failure With Preserved Ejection Fraction (WISE Pre-HFpEF) is a prospective cohort study enrolling 180 women and men undergoing clinically indicated invasive coronary angiography for suspected ischemia with no obstructive coronary artery disease. The study aims to investigate (1) CMD-related ischemia contribution to myocellular damage and impaired left ventricular (LV) relaxation as determined invasively by ultra-high sensitivity cardiac troponin I (u-hs-cTnI) measurements in the coronary sinus/great cardiac vein and LV pressure-volume loops, respectively, during provocative stress testing with isometric handgrip, and (2) CMD-related ischemic myocellular damage contribution to LV diastolic dysfunction progression as assessed using cardiac magnetic resonance imaging obtained at enrollment and 1-2 years later, along with prospectively repeated ambulatory u-hs-cTnI measurements.

CONCLUSIONS

The WISE pre-HFpEF study is designed to investigate whether ischemic myocardial damage secondary to CMD contributes to the progression of LV diastolic dysfunction. The findings from this study will provide new understanding of the role of CMD in HFpEF development as well as the potential benefits of CMD-directed therapies for the prevention and treatment of HFpEF.

TRIAL REGISTRATION

ClilicalTrial.gov, NCT03876223.

Associating electrocardiographic abnormalities with coronary artery disease: insights into microvascular dysfunction from dynamic CT perfusion

OBJECTIVES

Electrocardiographic (ECG) abnormalities serve as important predictors of future cardiovascular events. However, the specific cardiac abnormalities that bridge the gap between ECG abnormalities and subsequent events remain poorly understood. This study aimed to evaluate the relationship between ECG abnormalities and the prevalence of coronary artery disease (CAD) in propensity score-matched patients with suspected CAD who underwent comprehensive cardiac computed tomography (CT).

MATERIALS AND METHODS

A total of 357 patients suspected of CAD underwent ECG and cardiac CT assessments, including calcium scoring, stress dynamic CT perfusion (CTP), coronary CT angiography (CCTA), and CT late enhancement. Propensity score matching based on demographic parameters and CAD risk factors was performed, resulting in 286 matched patients (143 without ECG abnormalities and 143 with ECG abnormalities).

RESULTS

In both unadjusted and propensity score-matched analyses, ECG abnormalities were significantly associated with microvascular dysfunction and myocardial scarring (p < 0.05 for both analyses). However, no significant associations were observed between ECG abnormalities and coronary calcification severity or obstructive CAD (≥ 50% luminal narrowing) in the propensity score-matched patients. Among matched patients without obstructive CAD on CCTA, those with ECG abnormalities exhibited a higher prevalence (30%) of microvascular dysfunction, particularly in the diffuse-transmural pattern, compared to that (14%) of patients without ECG abnormalities (p < 0.01).

CONCLUSION

ECG abnormalities may not be reliable indicators of the presence of obstructive CAD. However, given their association with microvascular dysfunction, CAD evaluation with comprehensive cardiac CT, including dynamic CTP, is recommended for patients exhibiting ECG abnormalities, particularly to evaluate myocardial perfusion abnormalities.

KEY POINTS

Question We investigated whether ECG abnormalities in patients suspected of having CAD are linked to epicardial stenosis, microvascular dysfunction, or myocardial scarring. Findings After adjusting for traditional risk factors using propensity-score matching, ECG abnormalities were associated with microvascular dysfunction and myocardial scarring, but not with epicardial coronary stenosis. Clinical relevance These results suggest that ECG abnormalities may offer important insights into tissue-level changes and microvascular pathology, rather than simply reflecting epicardial stenosis, thereby underlining the need for comprehensive cardiac assessment in patients with ECG changes.

Endothelial Cell-Derived Extracellular Vesicles Allow to Differentiate Between Various Endotypes of INOCA: A Multicentre, Prospective, Cohort Study

Ischemia and non-obstructive coronary artery disease (INOCA) might be due to coronary microvascular dysfunction (CMD), vasospastic angina (VSA) or both. We compared plasma concentration of various extracellular vesicles (EVs) in patients with different INOCA endotypes. Patients were divided into those with INOCA (CMD, VSA, mixed CMD + VSA) and non-anginal chest pain. Plasma concentrations of EVs were measured using flow cytometry. Out of 96 patients included, 34 had CMD (35%), 15 VSA (16%), 24 mixed endotype (25%) and 23 non-anginal chest pain (24%). Patients with INOCA had lower ratio of endothelial EVs (CD144 +) to total EVs, compared to patients with non-anginal pain (p = 0.027). Patients with mixed endotype had lower ratio of endothelial EVs (CD144 +) to total EVs, compared to CMD (p = 0.008), VSA (p = 0.014) and non-anginal pain (p < 0.001). Decreased ratio of endothelial EVs (CD144 +) to total EVs might serve as a "circulating footprint" of the mixed INOCA endotype.

Coronary microvascular dysfunction: pathophysiology, diagnosis, and therapeutic strategies across cardiovascular diseases

Ischemic heart disease (IHD) is a leading cause of morbidity and mortality worldwide, presenting with acute and chronic coronary syndromes. Although coronary atherosclerosis is a major cause of IHD, many patients with angina or myocardial ischemia do not have obstructive coronary heart disease and impairment of the coronary microcirculation has been increasingly implicated as a relevant cause of IHD. Therefore, coronary microvascular dysfunction (CMD) refers to a term covering a wide spectrum of structural and functional alterations which affect the coronary microcirculation leading to myocardial ischemia and angina. The advent of non-invasive and invasive functional tests has exponentially broadened the ability to recognize CMD and delineate related clinical and biochemical features. Despite major advances in diagnosing and stratifying this condition, therapeutic strategies remain limited and poorly defined. In this review, we will provide an overview of the pathophysiology and the diagnostic evaluation of CMD across the spectrum of cardiovascular diseases. Furthermore, we will discuss the novel therapeutic strategies available for these patients in the perspective of a personalized medicine approach.

Does coronary microvascular dysfunction play a role in heart failure with reduced ejection fraction?

Heart failure (HF) is a conundrum in that, current therapies only slow the progression of the disease. We posit, if the causal mechanism were targeted, progression of the disease could be stopped and potentially reversed. We hypothesize that insufficient myocardial blood flow (MBF) produces minute areas of ischemia, that lead to an accumulating injury culminating in HF. Accordingly, we determined the relationship between MBF and cardiac work (wall stress-rate product [WSRP]) in control C57Bl6/J mice (Control), mice with transaortic constriction to produce HF (TAC-HF) and HF mice treated with the coronary vasodilator, chromonar (4 weeks of treatment, TAC-Chromonar). MBF and WSRP were measured during norepinephrine infusion in anesthetized mice. In Controls, MBF increased when work/WSRP was increased with norepinephrine, however, when cardiac work was increased in TAC-HF, MBF did not increase. After chromonar treatment, when work increased, MBF increased. Changes in cardiac function paralleled MBF, i.e., decrement in cardiac function occurred in TAC-HF (ejection fraction), but 4 weeks of chromonar treatment reversed this functional decline. We also found in a model of cardiac hypoxia fate-mapping, a 5-fold increase in the number of hypoxic cardiac myocytes (TAC-HF vs Control), which was reversed by chromonar. Capillary densities also followed this trend with a decrease from Control in TAC-HF, which was restored by Chromonar. We propose that a cause of HF is inadequate MBF to meet the metabolic demands of the working heart. Pharmacological coronary vasodilation with chromonar to increase MBF in HF can reverse the functional decline and improve cardiac function.

Promoting Resiliency to Stress in the Vascular Endothelium

By 2050, roughly 60% of the population will have cardiovascular disease. While a substantial amount of data has been generated over the last few decades that has aided in our understanding of cardiovascular disease pathology, less is known about how to increase resiliency to cardiovascular risk factors that individuals are exposed to on a daily basis. The vascular endothelium is considered the first line of defence against circulating noxious stimuli and, when dysfunctional, is an early risk factor for the development of cardiovascular disease. A vast amount of data has been generated demonstrating how external stress impairs the vascular endothelium; however, there is a paucity of knowledge regarding how to amplify protective pathways and ward off stress and the development of disease, which is the focus of this review. Targeting known protective endothelial pathways may be feasible to increase resiliency to vascular stress. Leveraging stress to boost defence mechanisms within the vascular endothelium is also proposed and may help identify novel therapeutic targets to protect individuals from the stress of everyday life.

Coronary Microvascular Dysfunction and Vasospastic Angina-Pathophysiology, Diagnosis and Management Strategies

Coronary artery disease is one of the leading public health problems in the world in terms of mortality and economic burden from the disease. Traditionally, the focus of research and clinical pathways leading to the diagnosis and treatment of coronary artery disease was on the more common variant of the disease resulting from atherosclerosis in the epicardial coronary arteries. However, coronary microvasculature, representing the vast majority of the total heart circulation, has the greatest influence on overall coronary resistance and, therefore, blood flow. Coronary microvascular dysfunction (CMD), characterized by structural or functional abnormalities in the microvasculature, significantly impacts myocardial perfusion. Endothelial dysfunction results in inadequate coronary dilation during exercise or spontaneous spasm in the microvasculature or epicardial arteries. A significant proportion of people presenting for coronary angiography in the context of angina have unobstructed epicardial coronary arteries yet are falsely reassured about the benign nature of their condition. Meanwhile, increasing evidence indicates that patients diagnosed with CMD as well as vasospastic angina (VSA) face an increased risk of Major Adverse Cardiovascular Events (MACEs), including death. The aim of this review is to outline the current practice with regard to invasive and non-invasive methods of CMD and VSA diagnosis and assess the evidence supporting the existing treatment strategies. These include endotype-specific pharmacological therapies, a holistic approach to lifestyle modifications and risk factor management and novel non-pharmacological therapies. Furthermore, the review highlights critical gaps in research and suggests potential areas for future investigation, to improve understanding and management of these conditions.

ANOCA updated: From pathophysiology to modern clinical practice

Lately, a large number of stable ischemic patients, with no obstructed coronary arteries are being diagnosed. Despite this condition, which is being described as angina with no obstructive coronary arteries (ANOCA), was thought to be benign, recent evidence report that it is associated with increased risk for adverse cardiovascular outcomes. ANOCA is more frequent in women and, pathophysiologically, it is predominantly related with microvascular dysfunction, while other factors, such as endothelial dysfunction, inflammation and autonomic nervous system seem to also play a major role to its development, while other studies implicate ANOCA and microvascular dysfunction in the pathogenesis of heart failure with preserved ejection fraction. For establishing an ANOCA diagnosis, measurement including coronary flow reserve (CFR), microvascular resistance (IMR) and hyperemic microvascular resistance (HMR) are mostly used in clinical practice. In addition, new modalities, such as optical coherence tomography (OCT) are being tested and show promising results for future diagnostic use. Regarding management, pharmacotherapy consists of a wide selection of drugs, according to the respected pathophysiology of the disease (vasospastic angina or microvascular dysfunction), while research for new treatment options including interventional techniques, is currently ongoing. This review, therefore, aims to provide a comprehensive analysis of all aspects related to ANOCA, from pathophysiology to clinical managements, as well as clinical implications and suggestions for future research efforts, which will help advance our understanding of the syndrome and establish more, evidence-based, therapies.

FFR, iFR, CFR, and IMR: Results from clinical trials

In this review article, we provide an overview of the definition and application of fractional flow reserve (FFR), instantaneous wave-free ratio (iFR), coronary flow reserve (CFR), and index of microvascular resistance (IMR) in the diagnosis, prognosis, and management of coronary microvascular dysfunction. We discuss their respective limitations as it relates to microvascular dysfunction. In each section, we review the most recent evidence supporting their use in microvascular and epicardial coronary artery disease. We also highlight specific clinical conditions with emerging indications for the use of these indices, including in the setting of microvascular dysfunction due to acute myocardial infarction, heart failure with preserved ejection fraction, and post-cardiac transplant.

Evolution of Coronary Microvascular Dysfunction Prevalence over Time and Across Diagnostic Modalities in Patients with ANOCA: A Systematic Review

Background: A considerable number of patients with angina undergo invasive coronary angiography, which might reveal non-obstructive coronary arteries (ANOCA). In this setting, they might have coronary microvascular disease (CMD). Its prevalence significantly varies in the literature. This systematic review aims to document the prevalence of CMD over time according to the diagnostic modalities. Methods: A systematic literature review was conducted using PubMed, the Cochrane Library, and Embase, covering publications from inception to 1 May 2024. Among 1471 identified articles, 297 full-text articles were assessed for eligibility. All studies reporting the prevalence of CMD in ANOCA patients based on invasive coronary artery (ICA), positron emission tomography-computed tomography (PET-CT), transthoracic echocardiography (TTE), or cardiac magnetic resonance (CMR) were included. Results: The review included 53 studies (published between 1998 and 2024), encompassing a total of 16,602 patients. Of these studies, 23 used ICA, 15 used PET-CT, 8 used TTE, and 7 used CMR. A statistically significant increase in CMD prevalence over time was observed across all diagnostic modalities (p < 0.05), except for PET-CT, which showed a consistent and stable prevalence over time. Notably, the prevalence rates from all of the diagnostic methods converged towards the 50% prevalence detected by PET-CT. Conclusions: The prevalence of CMD in patients with ANOCA is subject to debate. However, the current data suggest that regardless of the diagnostic method used, the most recent studies tend to converge towards a prevalence value of 50%, which has been consistently reported by PET-CT from the beginning.

Coronary microvascular function and atherosclerotic plaque burden in ischaemia and no obstructive coronary arteries: a secondary analysis of the CorMicA trial

BACKGROUND

The relationship between atherosclerosis and endotypes of myocardial ischaemia with no obstructive coronary artery disease (INOCA) is unclear. We investigated potential associations between cumulative atherosclerotic plaque burden quantified using the Gensini score, novel invasive indices of coronary microvascular function (microvascular resistance reserve (MRR); resistive reserve ratio (RRR)) and related INOCA endotypes.

METHODS

Coronary angiography and invasive coronary function tests were simultaneously acquired in the CorMicA cohort. A comprehensive physiological assessment was performed using both a thermodilution-based diagnostic guidewire and intracoronary acetylcholine provocation testing. Angiograms were examined for luminal stenosis in each segment of the SYNTAX coronary model. Cumulative plaque burden was quantified using the Gensini score, which incorporated both the number of diseased coronary segments and stenosis severity. Results were compared with indices of microvascular function and INOCA endotypes. Angiographic analyses were performed blind to coronary physiology findings.

RESULTS

In 151 participants (median age 61 years; 73.5% female) without flow-limiting coronary artery disease, medical history included 41.7% smoking, 63.6% hypertension and 19.2% diabetes mellitus. The left anterior descending artery underwent diagnostic guidewire testing in 85.4%, and 55.0% of participants had abnormal coronary flow reserve (CFR) and/or Index of Microcirculatory Resistance (IMR). The median Gensini score was 6.0 (IQR 2.5-11.0). CFR (p=0.012), MRR (p=0.026) and RRR (p=0.026), but not IMR (p=0.445), were univariably associated with raised Gensini scores. These significant effects persisted in multivariable models controlling for potential confounders. Considering INOCA endotypes, Gensini scores differed among participants with microvascular angina (MVA) (7.0 (2.5-11.0)), vasospastic angina (VSA) (4.5 (2.0-10.0)), mixed MVA/VSA (9.0 (5.0-11.5)) and non-cardiac symptoms (3.5 (1.5-8.0)); Kruskal-Wallis p=0.030.

CONCLUSIONS

Reduced CFR, MRR and RRR, and MVA were associated with increased coronary atherosclerotic plaque burden, as evidenced by higher Gensini scores. These novel findings provide a mechanistic link between INOCA and cardiovascular events, reinforcing the importance of antiatherosclerosis therapy in patients with MVA.

Coronary Microvascular Function in Asymptomatic Middle-Aged Individuals With Cardiometabolic Risk Factors

BACKGROUND

In patients with ischemic heart disease, coronary microvascular dysfunction is associated with cardiovascular risk factors and poor prognosis; however, data from healthy individuals are scarce.

OBJECTIVES

The purpose of this study was to assess the impact of cardiovascular risk factors and subclinical atherosclerosis on coronary microvascular function in middle-aged asymptomatic individuals.

METHODS

Myocardial perfusion was measured at rest and under stress using cardiac magnetic resonance in 453 individuals and used to generate myocardial blood flow (MBF) maps and calculate myocardial perfusion reserve (MPR). Subclinical atherosclerosis was assessed using 3-dimensional vascular ultrasound of the carotid and femoral arteries and coronary artery calcium scoring at baseline and at 3-year follow-up.

RESULTS

Median participant age was 52.6 years (range: 48.9-55.8 years), and 84.5% were male. After adjusting for age and sex, rest MBF was directly associated with the number of the metabolic syndrome components present (elevated waist circumference, systolic and diastolic blood pressure, fasting glucose, and triglycerides and low high-density lipoprotein cholesterol), insulin resistance (homeostatic model assessment for insulin resistance), and presence of diabetes. MPR was reduced in the presence of several metabolic syndrome components, elevated homeostatic model assessment for insulin resistance, and diabetes. Stress MBF was inversely associated with coronary artery calcium presence and with global plaque burden. Higher stress MBF and MPR were associated with less atherosclerosis progression (increase in plaque volume) at 3 years.

CONCLUSIONS

In asymptomatic middle-aged individuals free of known cardiovascular disease, the presence of cardiometabolic risk factors and systemic (poly-vascular) subclinical atherosclerosis are associated with impaired coronary microvascular function. Better coronary microvascular function reduces atherosclerosis progression at follow-up. (Progression of Early Subclinical Atherosclerosis [PESA]; NCT01410318).

Conjunctival microvascular alteration in patients with coronary artery disease assessed using optical coherence tomographic angiography

BACKGROUND

To quantify conjunctival microvascular characteristics obtained by optical coherence tomographic angiography (OCTA) and investigate their relationship with the presence and severity of coronary artery disease (CAD).

METHODS

This cross-sectional study included 103 consecutive CAD patients confirmed by coronary angiography and 125 non-CAD controls. The temporal conjunctivas along the limbus of each participant were scanned using OCTA. Quantification of conjunctival microvasculature was performed by AngioTool software. The severity of the disease was evaluated using SYNTAX and Gensini scores.

RESULTS

Compared to the controls, the CAD group exhibited significantly lower vessel area density (30.22 ± 3.34 vs. 26.70 ± 4.43 %, p < 0.001), lower vessel length density (6.39 ± 0.77 vs. 5.71 ± 0.89/m, p < 0.001), lower junction density (3.44 ± 0.56 vs. 3.05 ± 0.63/m, p < 0.001), and higher lacunarity (0.11 ± 0.03 vs. 0.14 ± 0.05, p < 0.001). Among all participants, lower vessel area density, lower vessel length density, lower junction density, and higher lacunarity were associated with greater odds of having CAD; the adjusted ORs (95 % confidence intervals) per one SD decrease were 2.71 (1.71, 4.29), 2.51(1.61, 3.90), 2.06 (1.39, 3.05), and 0.36 (0.23, 0.58), respectively. Among CAD patients, junction density was negatively associated with the Gensini score (r = -0.359, p = 0.037) and the Syntax score (r = -0.350, p = 0.042) in women but not in men (p > 0.05).

CONCLUSIONS

Conjunctival microvascular characteristics were significantly associated with the presence of CAD. Junction density significantly associated with the severity of CAD among women patients.

Respiratory Pathology and Cardiovascular Diseases: A Scoping Review

Respiratory diseases and cardiovascular diseases (CVDs) have high prevalence and share common risk factors. In some respiratory diseases such as sleep apnoea and COPD, the evidence of their negative impact on the prognosis of CVDs seems clear. However, in other diseases it is less evident whether there is any direct relationship. With this in mind, our objective was to provide information that may be helpful to better understand the relationship between respiratory pathology and CVDs. There are different reasons for this relationship, such as shared risk factors, common pathophysiological mechanisms, side effects of treatment and the direct effect in the heart and great vessels of respiratory diseases. Indeed, aging and smoking are risk factors for CVDs and also for respiratory diseases such as obstructive sleep apnea (OSA), COPD and interstitial lung diseases (ILD). Furthermore, there are common pathophysiological mechanisms that affect both respiratory diseases and CVDs, such as accelerated atherosclerosis, microvascular dysfunction, endothelial dysfunction, inflammation, hypoxemia and oxidative stress. Besides that, it is well known that lung cancer, sarcoidosis and amyloidosis may directly affect the heart and great vessels. Finally, side effects of drugs for respiratory diseases and the discontinuation of treatments that are necessary for CVDs, such as β-blockers and aspirin, may have a deleterious impact on the cardiovascular system. In conclusion, the coexistence of respiratory diseases and CVDs is very common. It makes modifying diagnostic and therapeutic management necessary and is also a relevant prognostic factor.

The Clinical Approach to Angina in Women

Women presenting with angina are more likely to have cardiac chest pain accompanied more frequently by associated symptoms like abdominal pain and lightheadedness. The evaluation of women with suspected coronary disease can be complex because many have microvascular dysfunction, coronary vasospasm, and altered coagulation that require specific testing protocols beyond the conventional stress testing and a coronary angiogram. Therefore, terms such as angina, ischemia, and myocardial infarction with no obstructive coronary disease have been introduced in recent years. More studies are required to elaborate guidelines on the diagnosis and management of these entities.

Association Between Nocturnal Hypoxemia Parameters and Coronary Microvascular Dysfunction: A Cross-Sectional Study

Objective

There is a connection between obstructive sleep apnea (OSA) and coronary microvascular dysfunction (CMD), but the underlying mechanisms remain unclear. This study aims to evaluate the correlation between OSA-related nocturnal hypoxemia parameters and CMD.

Methods

This is an observational, single-center study that included patients who underwent polysomnography and coronary angiography during hospitalization. The presence of CMD was determined by angio-based index of microcirculatory resistance (AccuIMR). Categorical variables were compared using chi-square test or Fisher exact test. The t-test and Mann-Whitney U-test were used to compare normally and non-normally distributed continuous variables, respectively. Univariate and multivariable logistic regression analyses were performed to evaluate the relationship between nocturnal hypoxemia parameters and CMD.

Results

A total of 133 patients were included in this study, of whom 72 (54.14%) had evidence of CMD. Patients with CMD exhibited a higher prevalence of OSA and experienced more severe nocturnal hypoxia. After adjusting for potential confounding factors, minimum oxygen saturation (minSpO2) ≤90% (OR 5.89; 95% CI 1.73-19.99; P=0.004) and the percentage of time spent with oxygen saturation below 90% (T90) ≥5% (OR 3.13; 95% CI 1.05-9.38; P=0.041) were independently associated with CMD. However, no significant association was observed between apnea-hypopnea index (AHI) and CMD.

Conclusion

Parameters of nocturnal hypoxemia are associated with CMD. Hypoxemia parameters may more sensitively reflect the correlation between OSA and CMD than AHI.

Coronary Sinus Reducer Improves Angina, Quality of Life, and Coronary Flow Reserve in Microvascular Dysfunction

BACKGROUND

Coronary microvascular dysfunction (CMD) is a common cause of angina with no obstructive coronary artery disease (ANOCA), and effective treatment options are limited.

OBJECTIVES

This study aims to assess the safety and efficacy of the coronary sinus (CS) Reducer (Neovasc, Inc/Shockwave Medical) for treatment of angina in patients with CMD.

METHODS

This Phase II trial enrolled 30 patients with ANOCA, invasively diagnosed CMD, and Canadian Cardiovascular Society (CCS) class 3 to 4 angina despite medical therapy. CMD was defined by coronary flow reserve (CFR) ≤2.5 and/or ≤50% increase in coronary blood flow (CBF) in response to intracoronary infusion of acetylcholine. Invasive coronary microvascular function testing was performed before and at 120 days postimplantation. The primary endpoint was change in microvascular function at 120 days. Secondary endpoints were changes in CCS angina class and Seattle Angina Questionnaire (SAQ) scores.

RESULTS

Mean age was 54.8 ± 11.0 years; 67% (20/30) were women. In patients with low baseline CFR (endothelium-independent CMD), CFR increased significantly from 2.1 (1.95-2.30) to 2.7 (2.45-2.95) (n = 19; P = 0.0011). Patients with abnormal CBF response to acetylcholine at baseline (endothelium-dependent CMD) had an increase in CBF response to acetylcholine: -11.0% (-20.15% to 5.85%) to 11.5% (-4.82% to 39.29%) (n = 11; P = 0.042). There was a significant improvement in CCS angina class from 4.0 (3.25-4.0) to 2.0 (2.0-3.0) (P < 0.001) and increase in each domain of the SAQ questionnaire (P < 0.006 for all).

CONCLUSIONS

This study demonstrates that the CS Reducer is associated with significant improvement in angina, quality of life, and coronary microvascular function in patients with CMD and may emerge as a novel therapy for patients with ANOCA.

Sex differences and determinants of coronary microvascular function in asymptomatic adults with type 2 diabetes

BACKGROUND

Coronary microvascular dysfunction (CMD) is a significant complication in type 2 diabetes (T2D) and may be more common in women. We aimed to evaluate the sex differences and sex-specific clinical determinants of CMD in adults with T2D without prevalent cardiovascular disease.

METHODS

Single center pooled analysis of four prospective studies comparing asymptomatic people with T2D and controls. All subjects underwent comprehensive cardiovascular phenotyping with myocardial perfusion reserve (MPR) quantified with perfusion cardiovascular magnetic resonance (CMR). Participants with silent coronary disease were excluded. Multivariable linear regression was performed to identify determinants of MPR with an interaction term for sex.

RESULTS

Four hundred and seventy-nine T2D (age 57 ± 11 years, 42% [202/479] women) were compared with 116 controls (age 53 ± 11 years, 41% [48/116] women). Men with T2D, but not women, demonstrated worse systolic function and higher extracellular volume fraction than controls. MPR was significantly lower in T2D than controls (women, 2.6 ± 0.9 vs 3.3 ± 1.0, p < 0.001; men, 3.1 ± 0.9 vs 3.5 ± 1.0, p = 0.004), and lower in women than men with T2D (p < 0.001). More women than men with T2D had MPR <2.5 (46% [79/202] vs 26% [64/277], p < 0.001). There was a significant interaction between sex and body mass index (BMI) for MPR (p interaction <0.001). Following adjustment for clinical risk factors, inverse association with MPR were BMI in women (β = -0.17, p = 0.045) and systolic blood pressure in men (β = -0.14, p = 0.049).

CONCLUSION

Among asymptomatic adults with T2D, women had a greater prevalence of CMD than men. Risk factors modestly but significantly associated with CMD in asymptomatic people with T2D were BMI among women and systolic blood pressure among men.

Sex-related differences in demographics, diagnosis and management of patients with chronic coronary syndromes

AIMS

The impact of sex-related factors on current clinical management and outcomes of chronic coronary syndromes (CCS) are unclear.

METHODS

All patients belonging to the prospective, nationwide START registry were included. Their baseline characteristics, diagnostic workup, revascularization strategy, pharmacological treatment and 1-year clinical outcomes were compared with respect to sex overall and in age tertiles.

RESULTS

A total of 5070 consecutive patients were included. Most patients were males (80.1%). As expected, the prevalence of females increased with age. Distribution of risk factors and history of cardiovascular disease were different depending on sex, as well as diagnostic workup, with lower use of exercise stress testing in women (25.1% vs. 36.7%, P < 0.0001). The use of coronary angiography was similar in the two groups. Women had lower rates of multivessel coronary artery disease (CAD) (33.0% vs. 40.6% P < 0.0001) and higher rates of nonobstructive CAD (18.3% vs. 11.3%, P < 0.0001). Rates of myocardial revascularization were similar, but women were more likely to receive percutaneous coronary intervention than men (84.3% vs. 77.8%, P < 0.0001) and less likely to receive surgical/hybrid revascularization (10.0% vs. 15.1%, P < 0.0001). At 12-month follow-up, no differences were observed for the combined endpoint of all-cause mortality, re-hospitalization for myocardial infarction, heart failure, stroke or myocardial revascularization between males and females; however, a significantly worse perceived quality of life was observed in women.

CONCLUSIONS

In a large nationwide cohort of patients with CCS, clinical outcomes were not different depending on sex. However, several differences in the diagnostic work-up, treatment strategies and quality of life were found between sexes.

Sex differences of sequential changes in coronary blood flow and microvascular function in patients with suspected angina

AIMS

This study evaluated the sex differences of sequential changes in coronary blood flows and microvascular function in patients with suspected angina but with no obstructed coronary arteries.

METHODS

A total of 202 consecutive patients who experienced chest pain but had no significant coronary artery stenosis and who underwent adenosine stress echocardiography were included in the study. Coronary blood flow (CBF) velocities were measured at 1, 2, and 3 min after adenosine infusion.

RESULTS

The mean age was 61 years, and 138 (68%) were women. Approximately 40% of patients had coronary microvascular dysfunction (CMD, coronary flow velocity reserve < 2.3), with women exhibiting higher CMD prevalence. The left ventricular (LV) mass index was similar between men and women, while women exhibited higher baseline rate pressure products (RPP). At baseline, coronary blood flow velocities were similar between the sexes. However, CBF velocities in women gradually increased during the examination; and in men, the increase was abrupt and steep during the early stages of examination (p = 0.015 for interaction between time and sex), even with similar RPP in stress. Coronary flow velocity reserve was steadily lower in women compared to men (1 min, 2.09 ± 0.86 vs 2.44 ± 0.87; 2 min, 2.39 ± 0.72 vs 2.63 ± 0.85; 3 min, 2.45 ± 0.70 vs 2.68 ± 0.73).

CONCLUSIONS

In patients with suspected angina but with no obstructed coronary arteries, CMD was especially prevalent among women. Women exhibited higher oxygen consumption, while exhibiting slower and gradual increases in CBF velocities. Conversely, men exhibited faster and steeper increases in CBF velocities even with similar RPP in stress.

Myocardial Infarction with Nonobstructive Coronary Artery Disease-Definition, Etiopathogenesis, Diagnosis, and Management

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is a complex clinical syndrome that is characterized by evidence of acute myocardial infarction in the absence of significant epicardial coronary artery disease on angiography. The term "MINOCA" encompasses a group of heterogeneous diseases with varying underlying mechanisms and each with its own pathophysiology. Overlooked plaque rupture or erosion and coronary vasospasm are the most common causes of MINOCA and can be diagnosed by routine intracoronary imaging and vasoreactivity testing, respectively. Coronary microvascular dysfunction is a less recognized, albeit an important cause of morbidity in patients presenting with MINOCA. Although MINOCA is a rare presentation of acute coronary syndrome, it is not a benign disorder and can have adverse consequences if untreated. In this article, we aim to review the pathogenesis, clinical characteristics, and finally propose a systematic approach in the diagnosis and management of patients with MINOCA.

Utilizing Invasive Coronary Functional Testing in a Coronary Microvascular and Vasomotor Dysfunction Program: Methods and Considerations

BACKGROUND

Coronary microvascular and vasomotor dysfunction (CMVD) is associated with a threefold increased risk of major adverse cardiovascular events (MACE) and is the primary mechanism responsible for angina/ischemia in patients with nonobstructive coronary artery disease (ANOCA/INOCA). Proper assessment for CMVD is vital to provide targeted treatment and improve patient outcomes. Invasive coronary functional testing (ICFT) is the "gold standard," for CMVD assessment and can be used to diagnose all endotypes. However, there is a lack of standardization for ICFT protocols and use in the treatment of CMVD.

AIMS

To provide a comprehensive overview of ICFT protocols utilized at the Christ Hospital Womens Heart Center (TCH-WHC).

METHODS

Here, we outline our standard operating procedures for ICFT utilized at TCH-WHC, including the procedures two main methods: Doppler and Thermodilution. We describe our structured approach for ICFT referral and postdiagnostic clinical management utilized at The Christ Hospital Women's Heart Center (TCH-WHC) CMVD program. We then quantified how ICFT has contributed to growth of the TCH-WHC.

RESULTS

From October of 2020 until July of 2024, a total of 422 patients have undergone ICFT at TCH-WCH, 64% were performed via the Doppler protocol and 36% were performed via the Thermodilution protocol. Based on exclusive endotype categories, 19% had an endothelial-independent CMD alone, 19% had endothelial-dependent CMD or microvascular VSA alone, 3% had epicardial VSA alone, 42% had mixed disease (any combination of the above categories), and 17% had a normal ICFT.

CONCLUSIONS

ICFT provides opportunity to provide diagnostic clarity and optimize medical treatment for CMVD. TCH-WHC's structured approach for ICFT referral and protocol for conducting comprehensive ICFT which has been vital for the growth of our specialized CMVD program.

[Chronic Heart Failure: Focus on Differences Between Men and Women]

This review focuses on the sex-related differences of patients in etiological factors, clinical picture, and objective laboratory and instrumental signs of heart failure. The authors performed an analysis of the effectiveness of drug and non-drug treatments depending on the gender of patients with low and preserved left ventricular ejection fraction, which should improve the quality of medical care and outcomes in patients with heart failure.

Feasibility and Improved Diagnostic Yield of Intracoronary Adenosine to Assess Microvascular Dysfunction With Bolus Thermodilution

BACKGROUND

Bolus thermodilution and intravenous adenosine are established methods for coronary microcirculatory assessment. Yet, its adoption remains low, partly due to procedural time and patient discomfort associated with intravenous adenosine. We investigated differences between intracoronary and intravenous adenosine using bolus thermodilution in terms of microcirculatory indices, procedural time, and side effects associated with adenosine in patients with myocardial ischemia and nonobstructive coronary arteries.

METHODS AND RESULTS

In this prospective, observational study, 102 patients with suspected myocardial ischemia and nonobstructive coronary arteries underwent measurements of mean transit time, coronary flow reserve, index of microcirculatory resistance, procedure time and patient tolerability with low-dose intracoronary adenosine, high-dose intracoronary adenosine (HDIC), and intravenous adenosine. HDIC induced greater hyperemia compared with low-dose intracoronary IC adenosine and intravenous adenosine with a shorter hyperemic mean transit time, P<0.0001. Coronary flow reserve was higher and index of microcirculatory resistance lowest with HDIC, compared with low-dose intracoronary IC adenosine and intravenous adenosine, P<0.05. Low coronary flow reserve was downgraded from 21% with intravenous adenosine to 10% with HDIC adenosine (P=0.031); high index of microcirculatory resistance was downgraded from 23% with intravenous adenosine to 14% with HDIC (P=0.098). Intracoronary adenosine was associated with lower procedural times (P<0.0001). More patients experienced chest pain with intravenous adenosine (P<0.01) and the chest pain intensity was higher compared with intracoronary adenosine (P<0.0001).

CONCLUSIONS

In patients with suspected myocardial ischemia and nonobstructive coronary arteries undergoing coronary microcirculatory assessment with bolus thermodilution, the use of HDIC compared with intravenous adenosine was associated with enhanced induction of hyperemia. The use of intracoronary adenosine allowed for a shorter procedure time and was better tolerated.

REGISTRATION+

URL: clinicaltrials.gov; Unique Identifier: NCT04827498.

Assessment of Coronary Microvascular Dysfunction by Angiography-Based Index of Microcirculatory Resistance: An Indirect Meta-Analysis

INTRODUCTION

There is a lack of consensus on diagnosing coronary microvascular dysfunction (CMD) using the angiography-based index of microcirculatory resistance (Angio-IMR) due to the absence of evidence. This study aimed to explore the efficacy of Angio-IMR in diagnosing CMD.

METHODS

A systematic search was conducted in PubMed, Embase, Scopus, and the Cochrane Library for studies primarily focusing on Angio-IMR diagnosing CMD, using IMR as the gold standard. The primary results were pooled sensitivity, specificity, and the area under the curve (AUC).

RESULTS

A total of 15 studies involving 2,202 individuals and 2,330 vessels were included in our study, Angio-IMR demonstrated high performance in predicting IMR with overall pooled sensitivity and specificity of 0.84 (95% confidence interval (CI): 0.81-0.87) and 0.87 (95% CI: 0.83-0.99), respectively, and AUC = 0.91 (95% CI: 0.89-0.94). This indicates that Angio-IMR has good diagnostic characteristics. Subgroup analysis by indirect meta-analysis showed higher sensitivity in the rest state. However, there is no significant difference in sensitivity and specificity between the hyperemic and rest states when using the AccuIMR system. Furthermore, sensitivity and specificity were more pronounced in the group without coronary pressure monitoring compared to the group with monitoring.

CONCLUSION

Angio-IMR is an alternative tool to identify CMD.

Association between the plasma ceramide and coronary microvascular resistance

BACKGROUND

Plasma ceramide plays a potentially significant role in the pathogenesis of coronary microvascular dysfunction. However, the relationship between plasma ceramide and coronary microvascular resistance in patients remains unclear. This study aimed to evaluate the association between plasma ceramide levels, as well as their distinct ratios, and coronary microvascular resistance.

METHODS

This single-center observational study retrospectively enrolled patients who underwent both ceramide measurement and coronary angiography during hospitalization. The microvascular resistance of the coronary arteries was assessed in all patients using the angiography-derived index of microcirculatory resistance (Angio-IMR). The cumulative coronary microvascular resistance was calculated by summing the microvascular resistance of the three main coronary arteries. Multiple linear and logistic regression analyses were employed to evaluate the relationship between plasma ceramide and cumulative coronary microvascular resistance. Restricted cubic spline (RCS) analysis was conducted to investigate the association between plasma ceramide levels and cumulative coronary microvascular resistance. Receiver operating characteristic (ROC) curves were employed to evaluate the predictive value of plasma ceramide for coronary microvascular resistance. Additionally, subgroup analyses and interaction tests were performed.

RESULTS

A total of 225 patients were included in this study, with a median cumulative coronary microvascular resistance of 48.04 (40.32-56.73). After adjusting for potential confounding factors, both plasma 16:0 ceramide and the 16:0/24:0 ceramide ratio were positively associated with cumulative coronary microvascular resistance [standardized β ± standard error: 75.05 ± 8.46 (P < 0.001) and 91.72 ± 20.41 (P < 0.001), respectively]. Similar independent associations were observed in predicting high cumulative microvascular resistance [β = 8.03 ± 1.91 (P < 0.001) and 9.98 ± 3.88 (P = 0.010), respectively]. Additionally, a significant nonlinear relationship was observed between plasma 16:0 ceramide, the 16:0/24:0 ceramide ratio, and cumulative coronary microvascular resistance (P for nonlinear < 0.05). The ROC analysis revealed that the optimal cut-off for plasma 16:0 ceramide is 0.178 µmol/L, with a specificity of 57.1% and a sensitivity of 91.2%. For the 16:0/24:0 ceramide ratio, the optimal cut-off is 0.072, yielding a specificity of 73.2% and a sensitivity of 54.9%. Subgroup analysis indicated that the association between plasma ceramide and coronary microvascular resistance was trending toward non-significance in patients with acute coronary syndrome (ACS).

CONCLUSIONS

A significant nonlinear relationship exists between plasma ceramide and coronary microvascular resistance, which holds important clinical implications for the risk stratification of coronary microvascular disease. New insights into the potential effects of ceramides enhance our understanding of the complex mechanisms underlying coronary microvascular disease and warrant further investigation in a broader population.

Basal Coronary Microvascular Resistance Predicting Death and Heart Failure in Patients Without Functional Coronary Stenosis

BACKGROUND

Abnormal coronary microcirculation is linked to poor patient prognosis, so the aim of the present study was to assess the prognostic relevance of basal microvascular resistance (b-IMR) in patients without functional coronary stenosis.

METHODS AND RESULTS

Analyses of 226 patients who underwent intracoronary physiological assessment of the left anterior descending artery included primary endpoints of all-cause death and heart failure, as well as secondary endpoints of cardiovascular death and atherosclerotic vascular events. During a median follow-up of 2 years, there were 12 (5.3%) primary and 21 (9.3 %) secondary endpoints. The optimal b-IMR cutoff for the primary endpoints was 47.1 U. Kaplan-Meier curve analysis demonstrated worse event-free survival of the primary endpoints in patients with a b-IMR below the cutoff (χ2=21.178, P<0.001). b-IMR was not significantly associated with the secondary endpoints (P=0.35). A low coronary flow reserve (CFR; <2.5) had prognostic value for both endpoints (primary endpoints: χ2=11.401, P=0.001; secondary endpoints: (χ2=6.015; P=0.014), and high hyperemic microvascular resistance (≥25) was associated only with the secondary endpoints (χ2=4.420; P=0.036). Incorporating b-IMR into a clinical model that included CFR improved the Net Reclassification Index and Integrated Discrimination Improvement for predicting the primary endpoints (P<0.001 and P=0.034, respectively).

CONCLUSIONS

b-IMR may be a specific marker of the risk of death and heart failure in patients without functional coronary stenosis.

The ANOCA/INOCA Dilemma Considering the 2024 ESC Guidelines on Chronic Coronary Syndromes

Cardiovascular disease remains a significant cause of morbidity and mortality worldwide, and its manifestations continue to pose a challenge in clinical practice [...].

Diagnostic Yield and Clinical Utility of Coronary Angiography Versus Coronary Function Testing in Women With Angina and Nonobstructive Coronary Arteries

BACKGROUND

Approximately 50% of women referred for invasive coronary angiography have angina and nonobstructive coronary arteries, which includes coronary microvascular dysfunction, vasospastic angina, and other vasomotor disorders. We sought to determine the real-world diagnostic yield of invasive coronary angiography and coronary function testing in women with angina and nonobstructive coronary arteries.

METHODS AND RESULTS

From 2018 to 2023, we enrolled 198 women who underwent either coronary angiography (CA) alone (n=99) or coronary function testing (CFT; n=99). Mean±SD age was 62±10 years (CA alone) compared with 57±10 years (CFT). Coronary angiography was interpreted as nonobstructive coronary artery disease more frequently after CA alone (79% versus 52%). Of the women who underwent CFT, 82% (N=81) were found to have vasomotor disorders, including coronary microvascular dysfunction (27%), vasospastic angina (32%), mixed coronary microvascular dysfunction/vasospastic angina (16%), endothelial dysfunction (10%; without spasm), elevated resting flow (2%), or symptomatic myocardial bridging (4%). Compared with women undergoing CA alone, medications were changed more frequently after CFT at 24 hours (41% versus 65%; P=0.001) and between 24 hours and 30 days (30% versus 44%; P=0.04) with intensification of antianginal therapy (79% versus 92%; P<0.0001) and increased use of calcium channel blockers (36% versus 63%; P<0.0001).

CONCLUSIONS

Our findings demonstrate that women presenting with suspected ischemic heart disease undergoing CA alone only received an anatomic diagnosis, whereas >80% of women undergoing CFT received a specific diagnosis of a coronary vasomotor disorder and greater intensification of antianginal therapy.

Coronary microvascular disease in women: epidemiology, mechanisms, evaluation, and treatment

Coronary microvascular dysfunction (CMD) involves functional or structural abnormalities of the coronary microvasculature resulting in dysregulation of coronary blood flow (CBF) in response to myocardial oxygen demand. This perfusion mismatch causes myocardial ischemia, which manifests in patients as microvascular angina (MVA). CMD can be diagnosed non-invasively via multiple imaging techniques or invasively using coronary function testing (CFT), which assists in determining the specific mechanisms involving endothelium-independent and dependent epicardial and microcirculation domains. Unlike traditional coronary artery disease (CAD), CMD can often occur in patients without obstructive atherosclerotic epicardial disease, which can make the diagnosis of CMD difficult. Moreover, MVA due to CMD is more prevalent in women and carries increased risk of future cardiovascular events. Successful treatment of symptomatic CMD is often patient-specific risk factor and endotype targeted. This article aims to review newly identified mechanisms and novel treatment strategies for managing CMD, and outline sex-specific differences in the presentation and pathophysiology of the disease.

Coronary artery bypass surgery versus percutaneous interventions for women with multivessel coronary artery disease

OBJECTIVE

To compare outcomes in women undergoing percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) surgery.

DESIGN

This retrospective, propensity-score matched cohort study from the New York State cardiac registry (2012-2018) included all women with multivessel coronary artery disease undergoing PCI with everolimus-eluting stents (EES) and CABG surgery. The primary outcome was all-cause mortality. The key secondary outcome was major adverse cardiac events, defined as the composite of all-cause mortality, myocardial infarction, and stroke.

RESULTS

PCI with EES was associated with a higher 6-year risk of mortality (25.75% vs 23.57%; adjusted hazard ratio [AHR], 1.29; 95% confidence interval [CI], 1.14-1.45). PCI also was associated with a higher rate of the composite outcome of death, myocardial infarction, and stroke (36.58% vs 32.89%; AHR, 1.28; 95% CI, 1.17-1.41), as well as myocardial infarction (14.94% vs 9.12%; AHR, 1.84; 95% CI, 1.56-2.17), but not stroke (7.07% vs 7.62%; AHR, 0.83; 95% CI, 0.67-1.03). Repeat revascularization rates also were higher for women undergoing PCI (21.53% vs 11.57%; AHR, 1.88; 95% CI, 1.63-2.17). There was no difference in mortality between the 2 interventions when PCI patients received complete revascularization or had noncomplex lesions and for women without diabetes.

CONCLUSIONS

For women with multivessel coronary artery disease, CABG surgery is associated with lower 6-year mortality, myocardial infarction, and repeat revascularization rates compared to PCI with EES.

Coronary microvascular dysfunction in autoimmune rheumatic diseases: beyond coronary flow velocity reserve

Autoimmune rheumatic diseases (ARDs) are a heterogeneous group of disorders characterized by an inappropriate immune reactivity against different body tissues. Patients affected by ARDs present increased cardiovascular morbidity and mortality, which significantly impacts long-term prognosis. Endothelial dysfunction, inflammation, oxidative stress, and autoimmunity are strictly involved in atherosclerosis progression and coronary microvascular dysfunction (CMD), both of which contribute to increased cardiovascular risk. CMD represents the inability of the coronary microvasculature to respond with vasodilation to increased cardiac metabolic demands and can be assessed by non-invasive and invasive imaging tests. Coronary flow velocity reserve assessed by echocardiography has been demonstrated to accurately identify ARDs patients with CMD. However, stress cardiac magnetic resonance (CMR) accurately assesses myocardial ischemia, perfusion, and viability in ARDs patients. The myocardial perfusion reserve index (MPRI) is a robust semiquantitative imaging marker that represents the vasodilatory capacity of the coronary microcirculation in response to a vasodilator stress. In the absence of significant coronary stenosis, ARDs patients revealed a reduced MPRI in comparison with the general population, regardless of the presence of myocardial fibrosis. Identification of CMD in asymptomatic patients could be crucial to precociously start targeted medical therapy, avoiding major adverse cardiac events in this clinical setting. This review aims to summarize the current evidence regarding CMD in ARDs patients, focusing on the role of stress CMR and the promising myocardial perfusion analysis.

Prognostic Implications of Resistive Reserve Ratio in Patients With Nonobstructive Coronary Artery Disease With Myocardial Bridging

BACKGROUND

Myocardial bridging (MB) is accompanied by the dynamic extravascular compression of epicardial coronary arteries, leading to intracoronary hemodynamic disturbance with abnormal coronary flow profiles. We aimed to evaluate the prognostic implications of resistive reserve ratio (RRR), a composite measure of flow and pressure parameters that represents the vasodilatory capacity of the coronary arteries, in patients with angina with nonobstructive coronary artery disease (ANOCA) and MB, in comparison with coronary flow reserve (CFR).

METHODS AND RESULTS

In this retrospective cohort study, we included patients with ANOCA who underwent coronary reactivity testing, where MB was identified by transient constriction in coronary artery segments between systole and diastole. Abnormal CFR and RRR were defined as <2.5 and <2.62, respectively. Major adverse cardiac events, including cardiovascular death, stroke, myocardial infarction, heart failure, and late revascularization, served as outcomes. Among 1251 patients with ANOCA, 191 (15.3%) had MB. The prevalence of abnormal CFR or RRR was not significantly different between patients with and without MB (P=0.144 and P=0.398, respectively). Over a median follow-up time of 6.9 years, abnormal RRR predicted major adverse cardiac events in patients with MB (hazard ratio [HR], 4.38 [95% CI, 1.71-11.21]; P=0.002) and without MB (HR, 1.91 [95% CI, 1.38-2.64]; P<0.001). Abnormal CFR predicted major adverse cardiac events in patients without MB (HR, 2.15 [95% CI, 1.54-3.00]; P<0.001), whereas it was not predictive of major adverse cardiac events in patients with MB (HR, 2.29 [95% CI, 0.93-5.65]; P=0.073).

CONCLUSIONS

In patients with ANOCA and MB, impaired RRR was superior to impaired CFR in distinguishing patients at a higher risk of future adverse events, suggesting that RRR may serve as a risk stratification tool in patients with MB and ANOCA.

Beyond Coronary Artery Disease: Assessing the Microcirculation

Ischemic heart disease (IHD) affects more than 20 million adults in the United States. Although classically attributed to atherosclerosis of the epicardial coronary arteries, nearly half of patients with stable angina and IHD who undergo invasive coronary angiography do not have obstructive epicardial coronary artery disease. Ischemia with nonobstructive coronary arteries is frequently caused by microvascular angina with underlying coronary microvascular dysfunction (CMD). Greater understanding the pathophysiology, diagnosis, and treatment of CMD holds promise to improve clinical outcomes of patients with ischemic heart disease.

Heterogeneity of coronary vascular function and myocardial oxygenation in women with angina and non-obstructive coronary artery disease

AIMS

Women with angina and non-obstructive coronary artery disease (ANOCA) have a heightened risk for cardiovascular events, and the pathophysiology for ischaemic symptoms may be related to alterations in microvascular structure and function. We examined the use of breathing-enhanced oxygenation-sensitive cardiac magnetic resonance imaging (OS-CMR) using vasoactive breathing manoeuvres to assess myocardial oxygenation in women with ANOCA.

METHODS AND RESULTS

We recruited women (aged 40-65 years) from two sites in Canada who presented to healthcare with persistent retrosternal chest pain and found to have ANOCA, or without a history of cardiovascular disease. All participants were scanned using a clinical 3T MRI scanner, and OS-CMR images were acquired over a breath hold following paced hyperventilation to measure global and regional measurements of heterogeneity. Fifty-four women with ANOCA (age: 55 ± 6.2 years) and 48 healthy controls (age: 51.2 ± 4.8 years) were recruited. There was no significant difference in volume, function, mass, or global myocardial oxygenation between the two groups [mean %Δ in signal intensity (SI): 4.9 (±7.3) vs. 4.5 (±10.1), P = 0.82]. Women with ANOCA had higher regional variations in myocardial oxygenation in circumferential [median %Δ in SI: 5.1 (2.0-7.6) vs. 2.2 (1.4-3.5), P = 0.0004] and longitudinal directions [median %Δ in SI: 11.4 (5.4-16.7) vs. 6.0 (3.0-7.0), P = 0.001], which remained present in a multivariate model.

CONCLUSION

Heterogeneous myocardial oxygenation may explain ischaemic symptoms without any associated epicardial obstructive coronary artery disease. Regional variations in myocardial oxygenation on OS-CMR could serve as an important diagnostic marker for microvascular dysfunction in women with ANOCA.

The role of cardiac PET in diagnosis and prognosis of patients with ischemia with no obstructive coronary arteries (INOCA)

Chest pain, a common symptom in cardiovascular care, often leads to the investigation of obstructive coronary artery disease (CAD). However, many patients experience chest pain without obstructive CAD, termed INOCA (Ischemia with Non-Obstructive Coronary Arteries) or CMD (Coronary Microvascular Dysfunction). INOCA can be attributed to endothelial dysfunction, vascular smooth muscle dysfunction, or both, affecting about 20-30 % of patients with nonobstructive CAD. The diagnostic approach for INOCA includes both invasive and non-invasive methods, with cardiac PET (Positron Emission Tomography) playing a significant role in risk stratification and management. PET evaluates various parameters like myocardial blood flow under stress and rest, myocardial flow reserve, and myocardial ischemia. Such comprehensive assessment is essential in accurately diagnosing and managing INOCA, considering the complexity of this condition.

Transcriptomic and spatial dissection of human ex vivo right atrial tissue reveals proinflammatory microvascular changes in ischemic heart disease

Cardiovascular disease plays a central role in the electrical and structural remodeling of the right atrium, predisposing to arrhythmias, heart failure, and sudden death. Here, we dissect with single-nuclei RNA sequencing (snRNA-seq) and spatial transcriptomics the gene expression changes in the human ex vivo right atrial tissue and pericardial fluid in ischemic heart disease, myocardial infarction, and ischemic and non-ischemic heart failure using asymptomatic patients with valvular disease who undergo preventive surgery as the control group. We reveal substantial differences in disease-associated gene expression in all cell types, collectively suggesting inflammatory microvascular dysfunction and changes in the right atrial tissue composition as the valvular and vascular diseases progress into heart failure. The data collectively suggest that investigation of human cardiovascular disease should expand to all functionally important parts of the heart, which may help us to identify mechanisms promoting more severe types of the disease.

Coronary microvascular dysfunction

Coronary microvascular dysfunction (CMD) is a key mechanism underlying ischemic heart disease (IHD), yet its diagnosis and treatment remain challenging. This article presents a comprehensive overview of CMD research, covering its pathogenesis, diagnostic criteria, assessment techniques, risk factors, and therapeutic strategies. Additionally, it highlights the prospects for future CMD research. The article aims at advocating early and effective intervention for CMD and improving the prognosis of IHD.

Arterial stiffness assessment in coronary microvascular dysfunction and heart failure with preserved ejection fraction: An initial report from the WISE-CVD continuation study

Background

Heart failure with preserved ejection fraction (HFpEF) is the most common cardiac complication in patients with coronary microvascular dysfunction (CMD), yet its underlying pathways remain unclear. Aortic pulse-wave velocity (aPWV) is an indicator of large artery stiffness and a predictor for cardiovascular disease. However, aPWV in CMD and HFpEF is not well characterized and may provide understanding of disease progression.

Methods

Among participants without obstructive coronary artery disease, we evaluated 51 women with suspected CMD and 20 women and men with evidence of HFpEF. All participants underwent aPWV measurement (SphygmoCor, Atcor Medical) with higher aPWV indicating greater vascular stiffness. Cardiac magnetic resonance imaging (CMRI) assessed left ventricular (LV) ejection fraction, CMD via myocardial perfusion reserve index (MPRI), and ventricular remodeling via LV mass-volume ratio. . Statistical analysis was performed using Wilcoxon rank sum tests, Pearson correlations and linear regression analysis.

Results

Compared to the suspected CMD group, the HFpEF participants were older (65 ± 12 vs 56 ± 11 yrs., p = 0.002) had higher BMI (31.0 ± 4.3 vs 27.8 ± 6.7 kg/m2, p = 0.013), higher aPWV (10.5 ± 2.0 vs 8.0 ± 1.6 m/s, p = 0.05) and lower MPRI (1.5 ± 0.3 vs1.8 ± 0.3, p = 0.02), but not remodeling. In a model adjusted for cardiovascular risk factors, the HFpEF group had a lower LVEF (estimate -4.78, p = 0.0437) than the suspected CMD group.

Conclusions

HFpEF participants exhibit greater arterial stiffness and lower myocardial perfusion reserve, with lower LVEF albeit not remodeling, compared to suspected CMD participants. These findings suggest arterial stiffness may contribute to progression from CMD to HFpEF. Prospective work is needed and ongoing.

The role of coronary microvascular dysfunction in the pathogenesis of heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is a common condition with few effective therapies and hence represents a major healthcare burden. The clinical syndrome of HFpEF can be caused by varying pathophysiological processes, with coronary microvascular dysfunction (CMD) proposed as one of the aetiologies, although confirming causality has been challenging. CMD is characterised by the inability of the coronary vasculature to augment blood flow in response to a physiological stressor and has been established as the driver of angina in patients with non-obstructed coronaries (ANOCA), and this has subsequently led to efficacious endotype-directed therapies. CMD is also highly prevalent among sufferers of HFpEF and may represent a novel treatment target for this particular endotype of this condition. This review aims to discuss the role of the microcirculation in the healthy heart how it's dysfunction may precipitate HFpEF and explore the current diagnostic tools available. We also discuss the gaps in evidence and where we believe future research should be focussed.

Traditional Cardiovascular Risk Factors and Coronary Microvascular Dysfunction in Women and Men: A Single-Center Study

INTRODUCTION

Coronary microvascular dysfunction (CMD) is common in patients with and without obstructive epicardial coronary artery disease (CAD). Risk factors for the development of CMD have not been fully elucidated, and data regarding sex-associated differences in traditional cardiovascular risk factors for obstructive CAD in patients with CMD are lacking.

METHODS

In this single-center, prospective registry, we enrolled patients with nonobstructive CAD undergoing clinically indicated invasive assessment of coronary microvascular function between November 2019 and March 2023. Associations between coronary microvascular dysfunction, traditional cardiovascular risk factors, and sex were assessed using univariate and multivariate regression models.

RESULTS

Overall, 245 patients with nonobstructive CAD were included in the analysis (62.9% female; median age 68 (interquartile range: 59, 75). Microvascular dysfunction was diagnosed in 141 patients (57.5%). The prevalence of microvascular dysfunction was similar in women and men (59.0% vs. 57.0%; p = 0.77). No association was found between traditional risk factors for coronary atherosclerosis and CMD regardless of whether CMD was structural or functional. In women, but not in men, older age and the presence of previous ischemic heart disease were associated with lower coronary flow reserve (β = -0.29; p < 0.01 and β = -0.15; p = 0.05, respectively) and lower resistive reserve ratio (β = -0.28; p < 0.01 and β = -0.17; p = 0.04, respectively).

CONCLUSION

For the entire population, no association was found between coronary microvascular dysfunction and traditional risk factors for coronary atherosclerosis. In women only, older age and previous ischemic heart disease were associated with coronary microvascular dysfunction. Larger studies are needed to elucidate risk factors for CMD.

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

Background

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

Methods

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

Results

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

Conclusions

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

Predicting the response to acetylcholine in ischemia or infarction with non-obstructive coronary arteries: The ABCD score

BACKGROUND AND AIMS

Acetylcholine (ACh) provocation testing can detect vasomotor disorders in patients with ischemia and non-obstructed coronary arteries (INOCA) or myocardial infarction and non-obstructed coronary arteries (MINOCA). We aimed to derive and validate a simple risk score to predict a positive ACh test response.

METHODS

We prospectively enrolled consecutive INOCA and MINOCA patients undergoing ACh provocation testing. Patients were split in two cohorts (derivation and validation) according to time of enrolment. The score was derived in 386 patients (derivation cohort) and then validated in 165 patients (validation cohort).

RESULTS

551 patients were enrolled, 371 (67.3%) INOCA and 180 (32.7%) MINOCA. ACh test was positive in 288 (52.3%) patients. MINOCA, myocardial bridge (MB), C-reactive protein (CRP) and dyslipidaemia were independent predictors of a positive ACh test in the derivation cohort. The ABCD (Acute presentation, Bridge, CRP, Dyslipidaemia) score was derived: 2 points were assigned to MINOCA, 3 to MB, 1 to elevated CRP and 1 to dyslipidaemia. The ABCD score accurately identified patients with a positive ACh test response with an AUC of 0.703 (CI 95% 0.652-0.754,p < 0.001) in the derivation cohort, and 0.705 (CI 95% 0.626-0.784, p < 0.001) in the validation cohort. In the whole population, an ABCD score ≥4 portended 94.3% risk of a positive ACh test and all patients with an ABCD score ≥6 presented a positive test.

CONCLUSIONS

The ABCD score could avoid the need of ACh provocation testing in patients with a high score, reducing procedural risks, time, and costs, and allowing the implementation of a tailored treatment strategy. These results are hypothesis generating and further research involving larger cohorts and multicentre trials is needed to validate and refine the ABCD score.

Physiology and functional significance of the coronary microcirculation: An overview of its implications in health and disease

Ischemic, Coronary Heart Disease (CHD) is a leading cause of morbidity and death worldwide.