Randomized evaluation of beta blocker and ACE-inhibitor/angiotensin receptor blocker treatment in patients with myocardial infarction with non-obstructive coronary arteries (MINOCA-BAT): Rationale and design

Sex Differences and Clinical Outcomes in Patients With Myocardial Infarction With Nonobstructive Coronary Arteries: A Meta-Analysis

BACKGROUND

Although myocardial infarction with nonobstructive coronary arteries (MINOCA) is more common in women, it is unknown whether sex is a risk factor for adverse outcomes in patients with MINOCA. We aimed to investigate the relationship between sex differences and outcomes of patients with MINOCA.

METHODS AND RESULTS

A systematic literature search was performed in PubMed, Embase, and Cochrane databases from their inception until August 2023 for relevant studies. End points were pooled using the Hartung-Knapp-Sidik-Jonkman random-effects model as odds ratio (OR) with 95% CIs. Nine studies, involving 30 281 patients with MINOCA (comprising 18 079 women and 12 202 men), were included in the study. Women were older and had a higher prevalence of hypertension, diabetes, and stroke compared with men. The median duration of follow-up was 3.5 years, with an interquartile range of 2.2 to 4.2 years. Pooled analysis revealed no statistically significant difference in the risk of all-cause mortality (OR, 1.03 [95% CI, 0.87-1.22]), major adverse cardiovascular events (OR, 1.18 [95% CI, 0.89-1.58]), heart failure (OR, 1.32 [95% CI, 0.57-3.03]), stroke (OR, 1.13 [95% CI, 0.56-2.26]), and myocardial infarction (OR, 1.04 [95% CI, 0.29-3.76]) between the 2 groups. Regarding short-term outcomes, women had a significantly higher risk of in-hospital major adverse cardiovascular events compared with men (OR, 1.33 [95% CI, 1.16-1.53]) whereas there was no significant difference in the risk of in-hospital mortality (OR, 0.90 [95% CI, 0.64-1.28]) between the 2 patient groups.

CONCLUSIONS

Despite the differences in demographics and comorbidity profiles, there was no significant difference in the long-term outcomes for patients with MINOCA between sexes. However, it is noteworthy that women experienced a higher risk of in-hospital major adverse cardiovascular events compared with men.

Effects of systematic cardiac rehabilitation training in elderly patients with unstable angina following cardiac stent implantation

BACKGROUND

Coronary stent implantation is usually used to treat unstable angina to alleviate stenosis or occlusion, promoting blood flow restoration and alleviating symptoms such as myocardial ischemia. And postoperative cardiac rehabilitation is essential for enhancing recovery and prognosis. Nevertheless, conventional rehabilitation lacks specificity, particularly for elderly patients with multiple comorbidities and poor compliance, rendering it less effective.

AIM

To investigate the effects of systematic cardiac rehabilitation training in elderly patients with unstable angina following coronary stenting intervention.

METHODS

A retrospective enrollment was conducted comprising fifty-four elderly patients with unstable angina pectoris who underwent systematic cardiac rehabilitation training after receiving coronary intervention as the rehabilitation group, while fifty-three elderly patients who received basic nursing and rehabilitation guidance measures after coronary intervention were assigned to the control group. Differences in Seattle Angina Questionnaire scores, survival quality (SF-36) scores, cardiopulmonary exercise function assessment index, echocardiographic cardiac function index, and adverse cardiovascular events were compared between the two groups.

RESULTS

After intervention, the rehabilitation group observed greater VO2 Max, maximum metabolic equivalent, eft ventricular ejection fraction, left ventricular end-diastolic diameter and smaller left ventricular end-systolic diameter. And the rehabilitation group observed greater scores of physical activity limitation, stable angina pectoris, treatment satisfaction, and SF-36 score. The incidence of adverse cardiovascular events in the two groups, showed no significant difference.

CONCLUSION

Systematic cardiac rehabilitation following coronary stenting in elderly patients with unstable angina pectoris can enhance cardiac function recovery, consequently enhancing both quality of life and cardiopulmonary exercise tolerance.

Sex-specific and ethnicity-specific differences in MINOCA

Suspected myocardial infarction with non-obstructive coronary arteries (MINOCA) has received increasing attention over the past decade. Given the heterogeneity in the mechanisms underlying acute myocardial infarction in the absence of obstructive coronary arteries, the syndrome of MINOCA is considered a working diagnosis that requires further investigation after diagnostic angiography studies have been performed, including coronary magnetic resonance angiography and functional angiography. Although once considered an infrequent and low-risk form of myocardial infarction, recent data have shown that the prognosis of MINOCA is not as benign as previously assumed. However, despite increasing awareness of the condition, many questions remain regarding the diagnosis, risk stratification and treatment of MINOCA. Women seem to be more susceptible to MINOCA, but studies on the sex-specific differences of the disease are scarce. Similarly, ethnicity-specific factors might explain discrepancies in the observed prevalence or underlying pathophysiological mechanisms of MINOCA but data are also scarce. Therefore, in this Review, we provide an update on the latest evidence available on the sex-specific and ethnicity-specific differences in the clinical features, pathophysiological mechanisms, treatment and prognosis of MINOCA.

Precision medicine in Myocardial Infarction With Non-obstructive Coronary Disease (MINOCA): A comprehensive review

Cardiovascular diseases, particularly myocardial infarction (MI), are a significant cause of mortality globally. Traditional MIs are commonly linked to substantial coronary artery blockage. However, a distinct subset of patients experience MI with non-obstructive coronary arteries, known as MINOCA. Imaging techniques, such as invasive coronary angiograms, are employed to diagnose MI or assess predisposition to one. Coronary angiograms help visualize vessel blockages; however, these blockages are absent in MINOCA cases, posing a diagnostic challenge. Precision medicine aims to introduce new diagnostic tools to assist in early diagnosis and further management of MINOCA. As percutaneous coronary intervention (PCI) does not benefit MINOCA patients, medical management tailored to the specific pathophysiological mechanism of MINOCA is employed. For example, if MINOCA is attributed to plaque disruption with or without plaque thrombus formation, the fundamental treatments may include statins, agents that modulate the renin-angiotensin system (RAS), and antiplatelet therapies. On the other hand, if coronary artery spasm is identified as the primary cause, essential intervention involves the use of calcium channel blockers. This approach has been previously utilized in patients with vasospastic angina and could be utilized in MINOCA, although research specific to MINOCA is ongoing. Therefore, the handling of MINOCA underscores the necessity for a tailored therapeutic strategy that corresponds to the underlying physiological mechanism responsible for the patient's clinical symptoms. Ongoing research initiatives are directed at expanding the availability of these treatments, uncovering new biomarkers, creating advanced diagnostic instruments, and establishing a more individualized approach for managing MINOCA patients.

Ischemia but no obstructive coronary artery disease: more than meets the eye

Symptomatic women with angina are more likely to have ischemia with no obstructive coronary arteries (INOCA) compared to men. In both men and women, the finding of INOCA is not benign and is associated with adverse cardiovascular events, including myocardial infarction, heart failure and angina hospitalizations. Women with INOCA have more angina and a lower quality of life compared to men, but they are often falsely reassured because of a lack of obstructive coronary artery disease (CAD) and a perception of low risk. Coronary microvascular dysfunction (CMD) is a key pathophysiologic contributor to INOCA, and non-invasive imaging methods are used to detect impaired microvascular flow. Coronary vasospasm is another mechanism of INOCA, and can co-exist with CMD, but usually requires invasive coronary function testing (CFT) with provocation testing for a definitive diagnosis. In addition to traditional heart disease risk factors, inflammatory, hormonal and psychological risk factors that impact microvascular tone are implicated in INOCA. Treatment of risk factors and use of anti-atherosclerotic and anti-anginal medications offer benefit. Increasing awareness and early referral to specialized centers that focus on INOCA management can improve patient-oriented outcomes. However, large, randomized treatment trials to investigate the impact on major adverse cardiovascular events (MACE) are needed. In this focused review, we discuss the prevalence, pathophysiology, presentation, diagnosis and treatment of INOCA.

Heart failure registries - Future directions

Heart failure (HF) is a growing, global public health issue. Despite advances in HF care, many challenges remain and HF outcomes are poor. Some of the major reasons for this are the lack of understanding and treatment for certain HF sub-types as well as the lack of implementation of treatment in areas where effective treatment exists. HF registries provide the opportunity to transform clinical research and patient care. Recently the registry-based randomized clinical trial has emerged as a pragmatic and inexpensive alternative to the gold standard in clinical trial design, the randomized controlled trial. Registries may also provide platforms for strategy trials, implementation trials, and screening. Using examples from the Swedish Heart Failure Registry and others, the present review provides insights into how registry-based research can address many of the unmet needs in HF.

MINOCA: Diagnostic work-up, risk stratification and tailored therapies

Myocardial infarction with no obstructive coronary artery disease (MINOCA) diagnostic work-up, risk stratification and tailored therapies are emerging as the recognition of this type of MI is increasingly recognized. Diagnostic workup using advanced imaging can include coronary angiography/intravascular ultrasound (IVUS)/optical coherent tomography (OCT), echo and cardiac magnetic resonance imaging (MRI). Risk stratification portends an intermediate risk compared to multivessel obstructive coronary artery disease (CAD). While event rates are high enough to warrant concern, they are relatively low enough to require trials with large sample sizes and hard outcomes. Tailored therapies include common sense therapeutic lifestyle change (TLC) and optimal medical therapy (OMT) due to the high prevalence of non-obstructive CAD, however therapeutic clinical trials are needed. Currently one large outcome trial in ischemia with no obstructive coronary artery disease (INOCA) is ongoing.

MINOCA: A Working Diagnosis

Cases of patients presenting with myocardial infarction (MI) without angiographic obstructive CAD are not trivial and have significant prevalence. "The Fourth Universal Definition of MI" (4UDMI) published in 2018 introduced MI with non-obstructive coronary arteries (MINOCA). The new section was of great importance as it validated the diagnosis by defining its criteria and recognizing its presence in the community and the need for further investigation. Given the nature of the diagnosis of MINOCA, coronary angiography provides limited information about prognosis and risk stratification for future major adverse cardiovascular events (MACE). Thus, additional imaging to understand the underlying etiology of MINOCA in conjunction with a better understanding of prognostic factors is necessary to expand on the current guidelines and aid in screening for possible complications, risk of MACE, and all-cause mortality. Discerning the etiology of the presentation is crucial, and physiologic studies, as well as additional imaging, are an important part of this evaluation. These modalities include intravascular studies such as optical coherence tomography (OCT), intravascular ultrasound (IVUS), fractional flow reserve (FFR), and imaging in the form of cardiac CT (CCT) and cardiac MRI (CMR). This step is essential to target treatment regimens more efficiently. The purpose of promoting multiple imaging modalities beyond traditional angiography is to address the working MINOCA diagnosis, with the finality of identifying the specific ischemic pathophysiology. MINOCA has multiple causative mechanisms, making it a heterogeneous collection of etiologies, resulting in acute MI: atherosclerotic, and non-atherosclerotic. This literature revision demonstrates that MINOCA prevalence and mortality are not trivial, and the diagnosis affects quality of life. MINOCA presents a definitive risk of MACE without proper stratification and targeted medical therapy. Several prognostic factors of morbidity and mortality in MI-CAD patients have been identified to correlate with MINOCA patients, especially inflammatory markers. MINOCA is not an exclusion diagnosis but a working diagnosis for which further imaging studies should be performed.

Migraine and cardiovascular disease: what cardiologists should know

Migraine is a chronic neurovascular disease with a complex, not fully understood pathophysiology with multiple causes. People with migraine suffer from recurrent moderate to severe headache attacks varying from 4 to 72 h. The prevalence of migraine is two to three times higher in women compared with men. Importantly, it is the most disabling disease in women <50 years of age due to a high number of years lived with disability, resulting in a very high global socioeconomic burden. Robust evidence exists on the association between migraine with aura and increased incidence of cardiovascular disease (CVD), in particular ischaemic stroke. People with migraine with aura have an increased risk of atrial fibrillation, myocardial infarction, and cardiovascular death compared with those without migraine. Ongoing studies investigate the relation between migraine and angina with non-obstructive coronary arteries and migraine patients with patent foramen ovale. Medication for the treatment of migraine can be preventative medication, such as beta-blockers, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, antiepileptics, antidepressants, some of the long-acting calcitonin gene-related peptide receptor antagonists, or monoclonal antibodies against calcitonin gene-related peptide or its receptor, or acute medication, such as triptans and calcitonin gene-related peptide receptor antagonists. However, these medications might raise concerns when migraine patients also have CVD due to possible (coronary) side effects. Specifically, knowledge gaps remain for the contraindication to newer treatments for migraine. All cardiologists will encounter patients with CVD and migraine. This state-of-the-art review will outline the basic pathophysiology of migraine and the associations between migraine and CVD, discuss current therapies, and propose future directions for research.

Prognostic Significance of Coronary Microvascular Dysfunction in Patients With Heart Failure With Preserved Ejection Fraction

BACKGROUND

The prognostic impact of coronary microvascular dysfunction (CMD) has been scarcely addressed in heart failure with preserved ejection fraction (HFpEF). This study investigated the prevalence and prognostic significance of CMD as measured by a novel pressure wire-free coronary angiography-derived index of microcirculatory resistance (caIMR) on clinical outcomes.

METHODS

Patients diagnosed with HFpEF from 2019 to 2021 were enrolled retrospectively. caIMR was used to quantify microvascular function, and patients were categorised into 2 groups based on their caIMR. The primary end points were composite of all-cause death and heart failure rehospitalisation.

RESULTS

Of 137 HFpEF patients, CMD (defined as caIMR ≥ 25) was present in 88 patients (64.2%). Forty-five patients (32.8%) experienced composite events during a mean follow-up of 15 months. Compared with patients with caIMR < 25, those with caIMR ≥ 25 had a notably higher incidence of composite events (16.3% vs 42.0%; P = 0.002). On survival analysis, patients with caIMR ≥ 25 demonstrated a worse prognosis than those with caIMR < 25 for composite events (P = 0.006). Patients with caIMR ≥ 25 in multiple coronary arteries showed a trend to worse outcome than those with caIMR ≥ 25 in a single coronary artery (log-rank P = 0.056). In adjusted analysis, caIMR ≥ 25 was independently predictive of adverse outcomes (adjusted hazard ratio 2.93, 95% confidence interval [CI] 1.28-6.70; P = 0.010). caIMR displayed a significant predictive power for adverse event prediction (area under the receiver operating characteristic curve 0.767, 95% CI 0.677-0.858; P < 0.001).

CONCLUSIONS

CMD is highly prevalent and is an independent predictor of adverse outcomes in HFpEF patients. Assessment of CMD may identify high-risk patients early for intensified treatment and risk-factor management.

Myocardial infarction with nonobstructive coronary arteries: from pathophysiology to therapeutic strategies

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is a heterogeneous group of clinical entities characterized by clinical evidence of acute myocardial infarction (AMI) with normal or near-normal coronary arteries on coronary angiography (stenosis < 50%) and without an over the alternative diagnosis for the acute presentation. Its prevalence ranges from 6% to 11% among all patients with AMI, with a predominance of young, nonwhite females with fewer traditional risks than those with an obstructive coronary artery disease (MI-CAD). MINOCA can be due to either epicardial causes such as rupture or fissuring of unstable nonobstructive atherosclerotic plaque, coronary artery spasm, spontaneous coronary dissection and cardioembolism in-situ or microvascular causes. Besides, also type-2 AMI due to supply-demand mismatch and Takotsubo syndrome must be considered as a possible MINOCA cause. Because of the complex etiology and a limited amount of evidence, there is still some confusion around the management and treatment of these patients. Therefore, the key focus of this condition is to identify the underlying individual mechanisms to achieve patient-specific treatments. Clinical history, electrocardiogram, echocardiography, and coronary angiography represent the first-level diagnostic investigations, but coronary imaging with intravascular ultrasound and optical coherent tomography, coronary physiology testing, and cardiac magnetic resonance imaging offer additional information to understand the underlying cause of MINOCA. Although the prognosis is slightly better compared with MI-CAD patients, MINOCA is not always benign and depends on the etiopathology. This review analyzes all possible pathophysiological mechanisms that could lead to MINOCA and provides the most specific and appropriate therapeutic approach in each scenario.

Contemporary Diagnosis and Management of Patients with MINOCA

PURPOSE OF REVIEW

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is defined as acute myocardial infarction (MI) with angiographically no obstructive coronary artery disease or stenosis ≤ 50%. MINOCA is diagnostically challenging and complex, making it difficult to manage effectively. This condition accounts for 6-8% of all MI and poses an increased risk of morbidity and mortality after diagnosis. Prompt recognition and targeted management are essential to improve outcomes and our understanding of this condition, but this process is not yet standardized. This article offers a comprehensive review of MINOCA, delving deep into its unique clinical profile, invasive and noninvasive diagnostic strategies for evaluating MINOCA in light of the lack of widespread availability for comprehensive testing, and current evidence surrounding targeted therapies for patients with MINOCA.

RECENT FINDINGS

MINOCA is not uncommon and requires comprehensive assessment using various imaging modalities to evaluate it further. MINOCA is a heterogenous working diagnosis that requires thoughtful approach to diagnose the underlying disease responsible for MINOCA further.

Coronary Physiology: Modern Concepts for the Guidance of Percutaneous Coronary Interventions and Medical Therapy

Recent evidence on ischemia, rather than coronary artery disease (CAD), representing a major determinant of outcomes, has led to a progressive shift in the management of patients with ischemic heart disease. According to most recent guidelines, myocardial revascularization strategies based on anatomical findings should be progressively abandoned in favor of functional criteria for the guidance of PCI. Thus, emerging importance has been assigned to the assessment of coronary physiology in order to determine the ischemic significance of coronary stenoses. However, despite several indexes and tools that have been developed so far, the existence of technical and clinical conditions potentially biasing the functional evaluation of the coronary tree still cause debates regarding the strategy of choice. The present review provides an overview of the available methods and the most recent acquirements for the invasive assessment of ischemia, focusing on the most widely available indexes, fractional flow reserve (FFR) and instant-wave free ratio (iFR), in addition to emerging examples, as new approaches to coronary flow reserve (CFR) and microvascular resistance, aiming at promoting the knowledge and application of those "full physiology" principles, which are generally advocated to allow a tailored treatment and the achievement of the largest prognostic benefits.

Myocardial infarction with non-obstructive coronary arteries: Etiology, diagnosis, treatment and prognosis

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is responsible for 10% of myocardial infarctions. Previously, patients were thought to have good prognosis, but evidence-based management and treatment strategies were scarce. Today, researchers and physicians recognize MINOCA as a condition with non-trivial mortality and morbidity. Therapeutic strategies are highly dependent on the underlying disease mechanism in each patient. However, to reach a diagnosis of MINOCA, a multimodal approach is required and, even with an optimal work-up, the cause remains unknown in 8-25% of patients. Research has been growing and position papers from the European Society of Cardiology (ESC) and the American Heart Association/American College of Cardiology have been published, and MINOCA has been included in the more recent ESC guidelines on myocardial infarction. Nonetheless, some clinicians still assume that the absence of coronary obstruction excludes the possibility of acute myocardial infarction. Therefore, in the present paper, we aim to compile and present the available data on the etiology, diagnosis, treatment, and prognosis of MINOCA.

Sex differences in treatment and outcomes amongst myocardial infarction patients presenting with and without obstructive coronary arteries: a prospective multicentre study

Aims

Women have an increased prevalence of myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA). Whether sex differences exist in the outcomes of patients with MI and obstructive coronary arteries (MIOCA) vs. MINOCA remains unclear. We describe sex-based differences in diagnosis, treatment, and clinical outcomes of patients with MINOCA vs. MIOCA.

Methods and results

A large-scale cohort study of patients with ST/non-ST elevation MI undergoing coronary angiography (01/2015-12/2019). Patient demographics, diagnosis, prescribed discharge medications, in-hospital complications, and follow-up data were prospectively collected. A total of 13 202 participants were included (males 68.2% and females 31.8%). 10.9% were diagnosed with MINOCA. Median follow-up was 4.62 years. Females (44.8%) were as commonly diagnosed with MINOCA as males (55.2%), unlike the male preponderance in MIOCA (male, 69.8%; female, 30.2%). Less secondary prevention medications were prescribed at discharge for MINOCA than MIOCA. There was no difference in mortality risk between MINOCA and MIOCA [in-hospital: adjusted odds ratio (OR) 1.32, 95% confidence interval (CI) 0.74-2.35, P = 0.350; long term: adjusted hazard ratio (HR) 1.03, 95% CI 0.81-1.31, P = 0.813]. MINOCA patients had reduced mortality at long-term follow-up if prescribed secondary prevention medications (aHR 0.64, 95% CI 0.47-0.87, P = 0.004). Females diagnosed with MIOCA had greater odds of in-hospital and 1-year mortality than males (aOR 1.50, 95% CI 1.09-2.07, P = 0.014; aHR 1.18, 95% CI 1.01-1.38, P = 0.048).

Conclusion

MINOCA patients have similar mortality rates as MIOCA patients. MINOCA patients were less likely than those with MIOCA to be discharged with guideline-recommended secondary prevention therapy; however, those with MINOCA who received secondary prevention survived longer. Females with MIOCA experienced higher mortality rates vs. males.

Emerging landscape of circFNDC3B and its role in human malignancies

In recent years, more attention has been paid to expanding the abundance of Circular RNAs (circRNAs), while the circRNAs that have been found to have significant functions have not been studied in different diseases. CircFNDC3B is one of the most researched circRNAs generated from fibronectin type III domain-containing protein 3B (FNDC3B) gene. Accumulating researches have reported the multiple functions of circFNDC3B in different cancer types and other non-neoplastic diseases, and predicted that circFNDC3B might be a potential biomarker. Notably, circFNDC3B can play roles in different diseases by binding to various microRNAs (miRNAs), binding to RNA-binding proteins (RBPs), or encoding functional peptides. This paper systematically summarizes the biogenesis and function of circRNAs, reviews and discusses the roles and molecular mechanisms of circFNDC3B and its target genes in different cancers and non-neoplastic diseases, which will do favor to broaden our comprehension of the function of circRNAs and facilitate subsequent research on circFNDC3B.

Myocardial Infarction with Nonobstructive Coronary Arteries

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is an important subtype of myocardial infarction (MI) that occurs in approximately 6-8% of patients with spontaneous MI who are referred for coronary angiography. MINOCA disproportionately affects women, but men are also affected. Pathogenesis is more variable than in MI with obstructive coronary artery disease (MI-CAD). Dominant mechanisms include atherosclerosis, thrombosis, and coronary artery spasm. Management of MINOCA varies based on the underlying mechanism of infarction. Therefore, systematic approaches to diagnosis are recommended. The combination of invasive coronary angiography, multivessel intracoronary imaging, provocative testing for coronary spasm, and cardiac magnetic resonance imaging provides the greatest diagnostic yield. Current clinical practice guidelines for the secondary prevention of MI are based largely on data from patients with MI-CAD. Thus, optimal medications after MINOCA are uncertain. Clinical trials focused on the treatment of patients with MINOCA are urgently needed to define optimal care.

Coronary microvascular dysfunction: A review of recent progress and clinical implications

The coronary microcirculation plays a cardinal role in regulating coronary blood flow to meet the changing metabolic demands of the myocardium. Coronary microvascular dysfunction (CMD) refers to structural and functional remodeling of the coronary microcirculation. CMD plays a role in the pathogenesis of obstructive and non-obstructive coronary syndromes as well as myocardial diseases, including heart failure with preserved ejection fraction (HFpEF). Despite recent diagnostic advancements, CMD is often under-appreciated in clinical practice, and may allow for the development of novel therapeutic targets. This review explores the diagnosis and pathogenic role of CMD across a range of cardiovascular diseases, its prognostic significance, and the current therapeutic landscape.

Precision medicine versus standard of care for patients with myocardial infarction with non-obstructive coronary arteries (MINOCA): rationale and design of the multicentre, randomised PROMISE trial

Myocardial infarction with non-obstructive coronary arteries (MINOCA) represents about 6-8% of patients presenting with myocardial infarction (MI), and it is associated with a significant risk of mortality, rehospitalisation, and angina burden, with high associated socioeconomic costs. It is important to note that multiple mechanisms may be responsible for MINOCA. However, to date, there are few prospective clinical trials on MINOCA and the treatment of these patients is still not defined, most likely because of the multiple underlying pathogenic mechanisms. The PROMISE trial is a randomised, multicentre, prospective, superiority, phase IV trial that will include 180 MINOCA patients randomised 1:1 to a "precision-medicine approach", consisting of a comprehensive diagnostic workup and pharmacological treatment specific for the underlying cause, versus a "standard of care" approach, consisting of routine diagnostic workup and standard medical treatment for acute coronary syndrome. The aim of this study is to evaluate if the "precision-medicine approach" will improve the angina status, evaluated using the Seattle Angina Questionnaire summary score, at 12 months (primary endpoint). Secondary endpoints include the rate of major adverse cardiovascular events at 12-month follow-up, the related primary and secondary healthcare costs, and the ability of cardiac magnetic resonance to evaluate the different mechanisms of MINOCA. Of importance, the results derived from this trial may pave the way for a new pathophysiology-driven approach with cause-target therapies personalised for the mechanisms of MINOCA (ClinicalTrials.gov: NCT05122780).

Diagnostic Value of Convolutional Neural Network Algorithm and High-Sensitivity Cardiac Troponin I Detection Under Machine Learning in Myocardial Infarction

Background: It aimed to the diagnosis and examination of acute myocardial infarction (AMI) using echocardiography under improved convolutional neural network (CNN) algorithm and high-sensitivity (Sen) cardiac troponin I (hs-cTnI) detection. The application effect was also evaluated. Methods: Ninety AMI patients were recruited as the AMI group, and ninety healthy individuals who underwent physical examinations simultaneously were chosen as control (Ctrl) group. Improved CNN algorithm-based echocardiography combined with hs-cTnI detection was applied, and its diagnostic efficiency was evaluated. Results: The optimal dataset scale (ODS), optimal image scale (OIS) and average precision (AP) of the proposed algorithm were better than those of manual labeling, Canny algorithm, and structured edge (SE) algorithm (P < 0.05). The left ventricular ejection fraction (LVEF) of the patients in the AMI group was inferior to that of Ctrl group ((55.09±2.78)%) versus (65.01±3.19)%), the left ventricular end-diastolic dimension (LVEDD) was superior to that of Ctrl group ((54.89±6.56) mm vs. (45.98±5.77) mm), and the cTnI level was also superior to that of Ctrl group ((2.90±0.31) pg/L vs. (0.73±0.42) pg/L) (P < 0.05). The diagnostic Sen (91.89%), specificity (Spe) (81.25%), accuracy (Acc) (90.00%) and consistency (0.56) of echocardiography combined with hs-cTnI were superior to those of single echocardiography or cTnI detection (P < 0.05).

Ischemia and no obstructive coronary arteries (INOCA): A narrative review

Myocardial ischemia with no obstructive coronary arteries (INOCA) is a chronic coronary syndrome condition that is increasingly being recognized as a substantial contributor to adverse cardiovascular mortality and outcomes, including myocardial infarction and heart failure with preserved ejection fraction (HFpEF). While INOCA occurs in both women and men, women are more likely to have the finding of INOCA and are more adversely impacted by angina, with recurrent hospitalizations and a lower quality of life with this condition. Abnormal epicardial coronary vascular function and coronary microvascular dysfunction (CMD) have been identified in a majority of INOCA patients on invasive coronary function testing. CMD can co-exist with obstructive epicardial coronary artery disease (CAD), diffuse non-obstructive epicardial CAD, and with coronary vasospasm. Epicardial vasospasm can also occur with normal coronary arteries that have no atherosclerotic plaque on intravascular imaging. While all predisposing factors are not clearly understood, cardiometabolic risk factors, and endothelium dependent and independent mechanisms that increase oxidative stress and inflammation are associated with microvascular injury, CMD and INOCA. Cardiac autonomic dysfunction has also been implicated in abnormal vasoreactivity and persistent symptoms. INOCA is under-recognized and under-diagnosed, partly due to the heterogenous patient populations and mechanisms. However, diagnostic testing methods are available to guide INOCA management. Treatment of INOCA is evolving, and focuses on cardiac risk factor control, improving ischemia, reducing atherosclerosis progression, and improving angina and quality of life. This review focuses on INOCA, relations to HFpEF, available diagnostics, current and investigational therapeutic strategies, and knowledge gaps in this condition.

Clinical Characteristics and Prognosis of MINOCA Caused by Atherosclerotic and Nonatherosclerotic Mechanisms Assessed by OCT

BACKGROUND

Myocardial infarction with nonobstructive coronary artery (MINOCA) is a heterogeneous syndrome caused by different pathophysiologic mechanisms. There is limited evidence regarding prognosis of patients with MINOCA caused by different mechanisms.

OBJECTIVES

The present study aimed to assess the underlying mechanisms of MINOCA by optical coherence tomography (OCT) and to correlate with clinical outcomes.

METHODS

Patients with MINOCA were divided into 2 groups based on OCT findings: atherosclerotic MINOCA (Ath-MINOCA) and nonatherosclerotic MINOCA (non-Ath-MINOCA). Major adverse cardiac events (MACE) were defined as cardiac death, nonfatal MI, target lesion revascularization, stroke, and rehospitalization for unstable or progressive angina.

RESULTS

Among 7,423 patients with a clinical diagnosis of MI who underwent angiography, 190 of 294 MINOCA were studied using OCT. The causes of Ath-MINOCA (n = 99, 52.1%) were plaque erosion (n = 64, 33.7%), plaque rupture (n = 33, 17.4%), and calcified nodule (n = 2, 1.1%) whereas the causes of non-Ath-MINOCA (n = 91, 47.9%) were spontaneous coronary artery dissection (n = 8, 4.2%), coronary spasm (n = 9, 4.7%), and unclassified cause (n = 74, 38.9%). The 1-year MACE was 15.3% for Ath-MINOCA vs 4.5% for non-Ath-MINOCA (P = 0.015). An atherosclerotic cause was an independent predictor of MACE (HR = 5.36 [95% CI: 1.08-26.55]; P = 0.040), mainly driven by target lesion revascularization and rehospitalization, despite the composite endpoint including cardiac death and MI showing no difference.

CONCLUSIONS

OCT identified a cause in 61.1% of MINOCA, in which Ath-MINOCA represents an important and distinct MINOCA subset. Ath-MINOCA were more common and associated with worse outcomes. (Incidence Rate of Heart Failure After Acute Myocardial Infarction With Optimal Treatment; NCT03297164) (Paradigm Shift in the Treatment of Patients With ACS; NCT02041650).

Myocardial infarction with non-obstructive coronary arteries (MINOCA)

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is evident in up to 15% of all acute myocardial infarctions (AMI) and disproportionally affects females. Despite younger age, female predominance, and fewer cardiovascular risk factors, MINOCA patients have a worse prognosis than patients without cardiovascular disease and a similar prognosis compared to patients with MI and obstructive coronary artery disease (CAD). MINOCA is a syndrome with a broad differential diagnosis that includes both ischemic [coronary artery plaque disruption, coronary vasospasm, coronary microvascular dysfunction, spontaneous coronary artery dissection (SCAD), and coronary embolism/thrombosis] and non-ischemic mechanisms (Takotsubo cardiomyopathy, myocarditis, and non-ischemic cardiomyopathy)-the latter called MINOCA mimickers. Therefore, a standardized approach that includes multimodality imaging, such as coronary intravascular imaging, cardiac magnetic resonance, and in selected cases, coronary reactivity testing, including provocation testing for coronary vasospasm, is necessary to determine underlying etiology and direct treatment. Herein, we review the prevalence, characteristics, prognosis, diagnosis, and treatment of MINOCA -a syndrome often overlooked.

Myocardial infarction with nonobstructive coronary arteries: the need for precision medicine

PURPOSE OF REVIEW

Myocardial infarction with nonobstructive coronary arteries (MINOCA) represents about 6-8% of all patients with myocardial infarction (MI), and several pathophysiological mechanisms showed to be involved in this heterogeneous clinical condition. Of note, MINOCA proved to be associated with a significant risk of mortality, angina burden and socioeconomic costs.

RECENT FINDINGS

Results from randomized clinical trials evaluating the clinical effectiveness of a comprehensive diagnostic algorithm, along with the acute and long-term management of patients with MINOCA, are pending.

SUMMARY

In this review article, we aim at providing an overview of the clinical features, diagnostic work-up and the therapeutic management of patients presenting with MINOCA, highlighting the recent acquisition along with the remaining important knowledge gaps in this field.

Small molecule angiotensin converting enzyme inhibitors: A medicinal chemistry perspective

Angiotensin-converting enzyme (ACE), a zinc metalloprotein, is a central component of the renin-angiotensin system (RAS). It degrades bradykinin and other vasoactive peptides. Angiotensin-converting-enzyme inhibitors (ACE inhibitors, ACEIs) decrease the formation of angiotensin II and increase the level of bradykinin, thus relaxing blood vessels as well as reducing blood volume, lowering blood pressure and reducing oxygen consumption by the heart, which can be used to prevent and treat cardiovascular diseases and kidney diseases. Nevertheless, ACEIs are associated with a range of adverse effects such as renal insufficiency, which limits their use. In recent years, researchers have attempted to reduce the adverse effects of ACEIs by improving the selectivity of ACEIs for structural domains based on conformational relationships, and have developed a series of novel ACEIs. In this review, we have summarized the research advances of ACE inhibitors, focusing on the development sources, design strategies and analysis of structure-activity relationships and the biological activities of ACE inhibitors.

[Takotsubo Syndrome: cardiovascular complication of stroke]

An 82-year-old woman, Katz A, with a history of type 2 diabetes mellitus and high blood pressure, was admitted for ischemic stroke complicated by Takotsubo´s syndrome with subsequent readmission for atrial fibrillation after discharge. These three clinical events have criteria to be integrated as a Brain Heart Syndrome, which is a high-risk condition for mortality.

Clinical Practice Variations in the Management of Ischemia With No Obstructive Coronary Artery Disease

Background Ischemia with no obstructive coronary artery disease is a condition associated with major adverse cardiovascular outcomes. To date, there are no specific American Heart Association or American College of Cardiology guidelines. The objective of this survey is to better understand the clinical practice and knowledge gaps that exist nationally. Methods and Results Participant-specific links for a survey with 11 questions and 3 reminders were sent between September and October 2020 to the American College of Cardiology CardioSurve Panel. The panel consist of randomly selected cardiologists (n=437) who represent the current profile of the American College of Cardiology US membership. The survey received a 30% response rate. Of the 172 respondents, 130 (76%) indicated that they have treated patients with ischemia with no obstructive coronary artery disease. Although the majority (69%) are generally confident in their ability to manage this condition, 1 of 3 report lack of confidence or are neutral. The American College of Cardiology/American Heart Association Chronic Stable Angina Guidelines are the most commonly used reference for treating ischemia with no obstructive coronary artery disease (81%), with most cardiologists wanting additional clinical guidance, such as randomized controlled trials (61%). More than 4 of 5 cardiologists rarely or never order advanced imaging modalities to assess coronary flow reserve. Approximately 2 of 3 of respondents frequently prescribe statins (68%), aspirin (66%), calcium channel blockers (63%), and β blockers or α/β blockers (55%). However, nearly 70% never prescribe angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Conclusions This survey demonstrates heterogeneity in the management of ischemia with no obstructive coronary artery disease among US cardiologists, identifies support for guideline development, and outlines knowledge gaps for research and education in the therapeutic management of this condition.

MINOCA: One Size Fits All? Probably Not—A Review of Etiology, Investigation, and Treatment

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a heterogeneous group of conditions that include both atherosclerotic (coronary plaque disruption) and non-atherosclerotic (spontaneous coronary artery dissection, coronary artery spasm, coronary artery embolism, coronary microvascular dysfunction, and supply–demand mismatch) causes resulting in myocardial damage that is not due to obstructive coronary artery disease. Failure to identify the underlying cause may result in inadequate and inappropriate therapy in these patients. The cornerstone of managing MINOCA patients is to identify the underlying mechanism to achieve the target treatment. Intravascular imaging is able to identify different morphologic features of coronary plaques, while cardiac magnetic resonance is the gold standard for detection of myocardial infarction in the setting of MINOCA. In this review, we summarize the relevant clinical issues, contemporary diagnosis, and treatment options of MINOCA.

Impact of secondary prevention medical therapies on outcomes of patients suffering from Myocardial Infarction with NonObstructive Coronary Artery disease (MINOCA): A meta-analysis

AIMS

To assess the impact of secondary prevention medical therapies (statins, ACE-inhibitors/Angiotensin Receptor Blockers (ARB), beta-blockers (BB) and Dual Antiplatelet Therapy (DAPT)) on outcomes of patients with myocardial infarction with nonobstructive coronary artery disease (MINOCA).

METHODS

Five adjusted observational studies encompassing 10,546 were included in this meta-analysis. All-cause death was the primary endpoint, while Major Adverse Cardiovascular Events (MACE) and acute myocardial infarction (AMI) were the secondary endpoints.

RESULTS

After 24 months of follow up, statins (tested in 8093 patients) were associated with a reduced risk of all-cause death (HR 0.60:0.45-0.81, p 〈0,001), while ACE-inhibitors/ARB (on 9666 patients) were not. Aggregate data from two studies (n = 9720, 7719 on beta-blockers, 6423 on DAPT) indicated that beta-blockers and DAPT (median follow-up 34.1 and 15.7 months, respectively) were both associated with a significant reduction of all-cause death (HR0.81:0.66-0.99, p = 0.04, and HR0.73:0.55-0.98, p = 0.03, for beta-blockers and DAPT, respectively). Among the investigated therapies, only ACE-inhibitors/ARBs entailed a reduced risk of MACE (HR0.65:0.44-0.94, p = 0.02, all CI 95%) over 36.5 months (four studies, n = 10,150). None of the investigated therapies was associated with a reduced risk of AMI.

CONCLUSIONS

Data from adjusted observational studies suggest that beta-blockers, statins and DAPT are associated with a survival benefit among MINOCA patients. ACE-inhibitors/ARB entail a reduced risk of MACE while none of the investigated secondary prevention therapies is associated with a reduced risk of AMI. Randomized controlled trials are warranted to confirm these findings.

Mechanisms of Coronary Ischemia in Women

PURPOSE OF REVIEW

Obstructive coronary artery disease is a major cause of ischemia in both men and women; however, women are more likely to present with ischemia in the setting of no obstructive coronary arteries (INOCA) and myocardial infarction with no obstructive coronary arteries (MINOCA), conditions that are associated with adverse cardiovascular prognosis despite absence of coronary stenosis. In this review, we focus on mechanisms of coronary ischemia that should be considered in the differential diagnosis when routine anatomic clinical investigation leads to the finding of non-obstructive coronary artery disease on coronary angiography in the setting of acute myocardial infarction.

RECENT FINDINGS

There are multiple mechanisms that contribute to MINOCA, including atherosclerotic plaque disruption, coronary artery spasm, coronary microvascular dysfunction (CMD), coronary embolism and/or thrombosis, and spontaneous coronary artery dissection. Non-coronary causes such as myocarditis or supply-demand mismatch should also be considered on the differential when there is an unexplained troponin elevation. Use of advanced imaging and diagnostic techniques to determine the underlying etiology of MINOCA is feasible and helpful, as this has the potential to guide management and secondary prevention. Failure to identify the underlying cause(s) may result in inappropriate treatment and inaccurate counseling to patients. MINOCA predominates in young women and is associated with a guarded prognosis. The diagnosis of MINOCA should prompt further investigation to determine the underlying cause of troponin elevation. Patients with INOCA and MINOCA are heterogeneous, and response to treatments can be variable. Large randomized controlled trials to determine longer-term optimal medical therapy for management of these conditions are under investigation.

Causes, Angiographic Characteristics, and Management of Premature Myocardial Infarction: JACC State-of-the-Art Review

Among patients presenting with acute myocardial infarction (AMI), the proportion of young individuals has increased in recent years. Although coronary atherosclerosis is less extensive in young patients with AMI, with higher prevalence of single-vessel disease and rare left main involvement, the long-term prognosis is not benign. Young patients with AMI with obstructive coronary artery disease have similar risk factors as older patients except for higher prevalence of smoking, lipid disorders, and family history of premature coronary artery disease, and lower prevalence of diabetes mellitus and hypertension. Smoking cessation is by far the most effective secondary preventive measure. Myocardial infarction with nonobstructive coronary arteries is a relatively common clinical entity (10%-20%) among young patients with AMI, with intravascular and cardiac magnetic resonance imaging being key for diagnosis and potentially treatment. Spontaneous coronary artery dissection is a frequent pathogenetic mechanism of AMI among young women, requiring a high degree of suspicion, especially in the peripartum period.

L-Carnitine Alleviates the Myocardial Infarction and Left Ventricular Remodeling through Bax/Bcl-2 Signal Pathway

Purpose

L-carnitine (LC) is considered to have good therapeutic potential for myocardial infarction (MI), but its mechanism has not been clarified. The aim of the study is to elucidate the cardioprotective effects of LC in mice following MI and related mechanisms.

Methods

ICR mice were treated with LC for 2 weeks after induction of MI with ligation of left anterior descending artery. Electrocardiographic (ECG) recording and echocardiography were used to evaluate cardiac function. H&E staining, TTC staining, and Masson staining were performed for morphological analysis and cardiac fibrosis. ELISA and immunofluorescence were utilized to detect biomarkers and inflammatory mediators. The key proteins in the Bax/Bcl-2 signaling pathway were also examined by Western blot.

Results

Both echocardiography and histological measurement showed an improvement in cardiac function and morphology. Biomarkers such as LDH, NT-proBNP, cTnT, and AST, as well as the inflammatory cytokines IL-1β, IL-6, and TNF-α, were decreased in plasma of mice receiving LC treatment after myocardial injury. In addition, the expression of α-SMA as well as the key proteins in the Bax/Bcl-2 signaling pathway in cardiac myocardium were much lower in mice with LC treatment compared to those without after MI.

Conclusions

Our data suggest that LC can effectively ameliorate left ventricular (LV) remodeling after MI, and its beneficial effects on myocardial function and remodeling may be attributable at least in part to anti-inflammatory and inhibition of the Bax/Bcl-2 apoptotic signaling pathway.

Myocardial Infarction With Non-obstructive Coronary Arteries: An Updated Overview of Pathophysiology, Diagnosis, and Management

Myocardial infarction with non-obstructive coronary arteries (MINOCA) refers to acute myocardial infarction with normal or near-normal coronary arteries. The MINOCA is a heterogeneous group of conditions, and possible etiologies are coronary artery spasm, spontaneous coronary artery dissection, coronary thromboembolism, coronary plaque disruption, coronary microvascular dysfunction, supply and demand mismatch. It is more common in young adults, with women having a higher chance of getting MINOCA than men. Considering MINOCA as a clinically dynamic working diagnostic that needs further investigation rather than a “true” diagnosis is proposed. Optical coherence tomography (OCT), intravenous ultrasound (IVUS), cardiac MRI may be required to stratify the underlying mechanism. Due to the lack of evidence-based literature and prospective randomized controlled studies, therapeutic management is limited. Consequently, the strategy is patient-specific. The prognosis of MINOCA patients remains unclear and depends upon the underlying etiology. This article aims to review the literature about various aspects of MINOCA, including pathophysiology, diagnosis, prognosis, and treatment.

Coronary Arterial Function and Disease in Women With No Obstructive Coronary Arteries

Ischemic heart disease (IHD) is the leading cause of mortality in women. While traditional cardiovascular risk factors play an important role in the development of IHD in women, women may experience sex-specific IHD risk factors and pathophysiology, and thus female-specific risk stratification is needed for IHD prevention, diagnosis, and treatment. Emerging data from the past 2 decades have significantly improved the understanding of IHD in women, including mechanisms of ischemia with no obstructive coronary arteries and myocardial infarction with no obstructive coronary arteries. Despite this progress, sex differences in IHD outcomes persist, particularly in young women. This review highlights the contemporary understanding of coronary arterial function and disease in women with no obstructive coronary arteries, including coronary anatomy and physiology, mechanisms of ischemia with no obstructive coronary arteries and myocardial infarction with no obstructive coronary arteries, noninvasive and invasive diagnostic strategies, and management of IHD.

Role of cardiac CT in the diagnostic evaluation and risk stratification of patients with myocardial infarction and non-obstructive coronary arteries (MINOCA): rationale and design of the MINOCA-GR study

INTRODUCTION

Myocardial infarction with non-obstructive coronary arteries (MINOCA) occurs in 5%-15% of all patients with acute myocardial infarction. Cardiac MR (CMR) and optical coherence tomography have been used to identify the underlying pathophysiological mechanism in MINOCA. The role of cardiac CT angiography (CCTA) in patients with MINOCA, however, has not been well studied so far. CCTA can be used to assess atherosclerotic plaque volume, vulnerable plaque characteristics as well as pericoronary fat tissue attenuation, which has not been yet studied in MINOCA.

METHODS AND ANALYSIS

MINOCA-GR is a prospective, multicentre, observational cohort study based on a national registry that will use CCTA in combination with CMR and invasive coronary angiography (ICA) to evaluate the extent and characteristics of coronary atherosclerosis and its correlation with pericoronary fat attenuation in patients with MINOCA. A total of 60 consecutive adult patients across 4 participating study sites are expected to be enrolled. Following ICA and CMR, patients will undergo CCTA during index hospitalisation. The primary endpoints are quantification of extent and severity of coronary atherosclerosis, description of high-risk plaque features and attenuation profiling of pericoronary fat tissue around all three major epicardial coronary arteries in relation to CMR. Follow-up CCTA for the evaluation of changes in pericoronary fat attenuation will also be performed. MINOCA-GR aims to be the first study to explore the role of CCTA in combination with CMR and ICA in the underlying pathophysiological mechanisms and assisting in diagnostic evaluation and prognosis of patients with MINOCA.

ETHICS AND DISSEMINATION

The study protocol has been approved by the institutional review board/independent ethics committee at each site prior to study commencement. All patients will provide written informed consent. Results will be disseminated at national meetings and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT4186676.

Coronary microvascular dysfunction as a chronic inflammatory state: Is there a role for omega-3 fatty acid treatment?

Coronary microvascular dysfunction is a ubiquitous pathologic process that is operational in ischemia with no obstructive coronary artery disease and other cardiovascular disorders including heart failure with preserved ejection fraction. It may, in fact, be a manifestation of a multi-systemic condition of small vessel dysfunction that also affects the brain and kidneys. While the pathophysiology driving coronary microvascular dysfunction is multifactorial, chronic inflammation plays an important role. Resolution of inflammation is an active process mediated, in part, by a family of locally active mediators biosynthesized from omega-3 fatty acids, collectively referred to as specialized pro-resolving mediators. Omega-3 fatty acid treatment modulates inflammation and is associated with improved cardiovascular outcomes and attenuation of plaque progression on cardiovascular imaging. Whether omega-3 fatty acid treatment attenuates coronary microvascular dysfunction is unknown.

Role of Multimodality Imaging in the Assessment of Myocardial Infarction With Nonobstructive Coronary Arteries: Beyond Conventional Coronary Angiography

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is a heterogeneous clinical entity, encompassing multiple different causes, and a cause of substantial morbidity and mortality. Current guidelines suggest a multimodality imaging approach in establishing the underlying cause for MINOCA, which is considered a working diagnosis. Recent studies have suggested that an initial workup consisting of cardiac magnetic resonance and invasive coronary imaging can yield the diagnosis in most patients. Cardiac magnetic resonance is particularly helpful in excluding nonischemic causes that can mimic MINOCA including myocarditis and Takotsubo cardiomyopathy, as well as for long‐term prognostication. Additionally, intracoronary imaging with intravascular ultrasound or optical coherence tomography may be warranted to evaluate plaque composition, or evaluate for plaque disruption or spontaneous coronary dissection. The role of noninvasive imaging modalities such as coronary computed tomography angiography is currently being investigated in the diagnostic approach and follow‐up of MINOCA and may be appropriate in lieu of invasive coronary angiography in select patients. In recent years, many strides have been made in the workup of MINOCA; however, significant knowledge gaps remain in the field, particularly in terms of treatment strategies. In this review, we summarize recent society guideline recommendations and consensus statements on the initial evaluation of MINOCA, review contemporary multimodality imaging approaches, and discuss treatment strategies including an ongoing clinical trial.

Myocardial infarction with non-obstructive coronary artery disease

As a result of the increased use of coronary angiography in acute myocardial infarction in the last two decades, myocardial infarction with non-obstructive coronary arteries (MINOCA) has received growing attention in everyday clinical practice. At the same time, research interest in MINOCA has increased significantly. MINOCA is a heterogeneous disease entity seen in 5-10% of all patients with myocardial infarction, especially in women. Clinically, MINOCA may be difficult to distinguish from other non-ischaemic conditions that can cause similar symptoms and myocardial injury. There is still some confusion around the diagnosis, investigation and management of patients with MINOCA. The present review summarises the current knowledge of MINOCA regarding epidemiology, pathophysiology, investigation, and treatment, with a special focus on imaging modalities. In addition, remaining important knowledge gaps are highlighted.

Clinical presentation and management of myocardial infarction with nonobstructive coronary arteries (MINOCA): A literature review

Myocardial Infarction with Nonobstructive Coronary Arteries (MINOCA), as the name implies, is an acute myocardial infarction (MI) in the absence of significant coronary artery obstruction. Diagnosis and management of such cases have been challenging. There are many etiologies of MINOCA including coronary artery spasm, coronary microvascular dysfunction, plaque disruption, spontaneous coronary thrombosis or emboli, spontaneous coronary artery dissection, or cardiomyopathies. In this paper, the pathophysiology, diagnostic work-up, and clinical management for each subtype are described, and an overarching approach on how to evaluate and manage a patient presenting with MINOCA.

Beta-blockers in patients without heart failure after myocardial infarction

BACKGROUND

Cardiovascular disease is the number one cause of death globally. According to the World Health Organization (WHO), 7.4 million people died from ischaemic heart disease in 2012, constituting 15% of all deaths. Beta-blockers are recommended and are often used in patients with heart failure after acute myocardial infarction. However, it is currently unclear whether beta-blockers should be used in patients without heart failure after acute myocardial infarction. Previous meta-analyses on the topic have shown conflicting results. No previous systematic review using Cochrane methods has assessed the effects of beta-blockers in patients without heart failure after acute myocardial infarction.

OBJECTIVES

To assess the benefits and harms of beta-blockers compared with placebo or no treatment in patients without heart failure and with left ventricular ejection fraction (LVEF) greater than 40% in the non-acute phase after myocardial infarction.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS, Science Citation Index - Expanded, BIOSIS Citation Index, the WHO International Clinical Trials Registry Platform, ClinicalTrials.gov, European Medicines Agency, Food and Drug Administration, Turning Research Into Practice, Google Scholar, and SciSearch from their inception to February 2021.

SELECTION CRITERIA

We included all randomised clinical trials assessing effects of beta-blockers versus control (placebo or no treatment) in patients without heart failure after myocardial infarction, irrespective of publication type and status, date, and language. We excluded trials randomising participants with diagnosed heart failure at the time of randomisation.

DATA COLLECTION AND ANALYSIS

We followed our published protocol, with a few changes made, and methodological recommendations provided by Cochrane and Jakobsen and colleagues. Two review authors independently extracted data. Our primary outcomes were all-cause mortality, serious adverse events, and major cardiovascular events (composite of cardiovascular mortality and non-fatal myocardial reinfarction). Our secondary outcomes were quality of life, angina, cardiovascular mortality, and myocardial infarction during follow-up. We assessed all outcomes at maximum follow-up. We systematically assessed risks of bias using seven bias domains and we assessed the certainty of evidence using the GRADE approach.

MAIN RESULTS

We included 25 trials randomising a total of 22,423 participants (mean age 56.9 years). All trials and outcomes were at high risk of bias. In all, 24 of 25 trials included a mixed group of participants with ST-elevation myocardial infarction and non-ST myocardial infarction, and no trials provided separate results for each type of infarction. One trial included participants with only ST-elevation myocardial infarction. All trials except one included participants younger than 75 years of age. Methods used to exclude heart failure were various and were likely insufficient. A total of 21 trials used placebo, and four trials used no intervention, as the comparator. All patients received usual care; 24 of 25 trials were from the pre-reperfusion era (published from 1974 to 1999), and only one trial was from the reperfusion era (published in 2018). The certainty of evidence was moderate to low for all outcomes. Our meta-analyses show that beta-blockers compared with placebo or no intervention probably reduce the risks of all-cause mortality (risk ratio (RR) 0.81, 97.5% confidence interval (CI) 0.73 to 0.90; I² = 15%; 22,085 participants, 21 trials; moderate-certainty evidence) and myocardial reinfarction (RR 0.76, 98% CI 0.69 to 0.88; I² = 0%; 19,606 participants, 19 trials; moderate-certainty evidence). Our meta-analyses show that beta-blockers compared with placebo or no intervention may reduce the risks of major cardiovascular events (RR 0.72, 97.5% CI 0.69 to 0.84; 14,994 participants, 15 trials; low-certainty evidence) and cardiovascular mortality (RR 0.73, 98% CI 0.68 to 0.85; I² = 47%; 21,763 participants, 19 trials; low-certainty evidence). Hence, evidence seems to suggest that beta-blockers versus placebo or no treatment may result in a minimum reduction of 10% in RR for risks of all-cause mortality, major cardiovascular events, cardiovascular mortality, and myocardial infarction. However, beta-blockers compared with placebo or no intervention may not affect the risk of angina (RR 1.04, 98% CI 0.93 to 1.13; I² = 0%; 7115 participants, 5 trials; low-certainty evidence). No trials provided data on serious adverse events according to good clinical practice from the International Committee for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH-GCP), nor on quality of life.

AUTHORS' CONCLUSIONS

Beta-blockers probably reduce the risks of all-cause mortality and myocardial reinfarction in patients younger than 75 years of age without heart failure following acute myocardial infarction. Beta-blockers may further reduce the risks of major cardiovascular events and cardiovascular mortality compared with placebo or no intervention in patients younger than 75 years of age without heart failure following acute myocardial infarction. These effects could, however, be driven by patients with unrecognised heart failure. The effects of beta-blockers on serious adverse events, angina, and quality of life are unclear due to sparse data or no data at all. All trials and outcomes were at high risk of bias, and incomplete outcome data bias alone could account for the effect seen when major cardiovascular events, angina, and myocardial infarction are assessed. The evidence in this review is of moderate to low certainty, and the true result may depart substantially from the results presented here. Future trials should particularly focus on patients 75 years of age and older, and on assessment of serious adverse events according to ICH-GCP and quality of life. Newer randomised clinical trials at low risk of bias and at low risk of random errors are needed if the benefits and harms of beta-blockers in contemporary patients without heart failure following acute myocardial infarction are to be assessed properly. Such trials ought to be designed according to the SPIRIT statement and reported according to the CONSORT statement.

Syndrome of Nonobstructive Coronary Artery Diseases: A Comprehensive Overview of Open Artery Ischemia

Syndromes of cardiac ischemia with nonobstructive coronary arteries have been increasingly recognized as a clinical entity with heterogeneous clinical presentations, commonly encountered in women. Knowledge of pathophysiology and clinical risk factors is key to ensuring appropriate diagnostic evaluation and management for these often-neglected patients. In this review, we discuss the epidemiology, risk factors, and clinical presentations of these syndromes. We provide algorithms for diagnosis and management of these entities based on current scientific knowledge and highlight some of the key knowledge gaps and ongoing trials in this emerging field.

Randomized Evaluation of Beta Blocker and ACE-Inhibitor/Angiotensin Receptor Blocker Treatment for Post Infarct Angina in Patients With Myocardial Infarction With Non-obstructive Coronary Arteries: A MINOCA-BAT Sub Study Rationale and Design

Introduction: Myocardial infarction with non-obstructive coronary arteries (MINOCA) occurs in ~10% of all patients with acute myocardial infarction (AMI), with an over-representation amongst women. Remarkably, it is estimated that as many as 1 in 4 patients with MINOCA experience ongoing angina at 12 months despite having no flow-restricting stenoses in their epicardial arteries. This manuscript presents the rationale behind Randomized Evaluation of Beta Blocker and Angiotensin-converting enzyme inhibitors/Angiotensin Receptor Blocker Treatment (ACEI/ARB) for Post Infarct Angina in MINOCA patients-The MINOCA BAT post infarct angina sub study. Methods: This trial is a registry-based, randomized, parallel, open-label, multicenter trial with 2 × 2 factorial design. The primary aim is to determine whether oral beta blockade compared with no oral beta blockade, and ACEI/ARB compared with no ACEI/ARB, reduce post infarct angina in patients discharged after MINOCA without clinical signs of heart failure and with left ventricular ejection fraction ≥40%. A total of 664 patients will be randomized into four groups; (i) ACEI/ARB with beta blocker, (ii) beta blocker only, (iii) ACEI/ARB only, or (iv) neither ACEI/ARB nor beta blocker and followed for 12 months. Results: The trial is currently recruiting in Australia and Sweden. Fifty six patients have been recruited thus far. Both sexes were equally distributed (52% women and 48% men) and the mean age was 56.3 ± 9.9 years. Conclusions: It remains unclear whether conventional secondary preventive therapies are beneficial to MINOCA patients in regard to post infarct angina. Existing registry-based literature suggest cardioprotective agents are less likely to be used in MINOCA patients. Thus, results from this trial will provide insights for future treatment strategies and guidelines specific to MINOCA patients.

Comparing pharmacotherapy in MINOCA versus medically managed obstructive acute coronary syndrome

Most prior studies have compared myocardial infarction with non-obstructive coronary arteries (MINOCA), to obstructive acute coronary syndrome (ACS) often requiring revascularisation. However, these were subject to treatment bias given the significant differences in management. This study uniquely compares the management and outcomes of MINOCA patients with a medically managed obstructive ACS (M-ACS) population. We retrospectively analysed registry data for consecutive patients admitted to the Gold Coast University Hospital with ACS requiring coronary angiography and identified patients with MINOCA and M-ACS. Baseline characteristics, pharmacological therapy and in-hospital outcomes were compared. In hospital outcomes were composite NACE, heart failure, stroke and major bleeding. Multivariate regression analysis was also performed to identify independent predictors of MINOCA. Multivariate regression analysis was also performed to identify independent predictors of MINOCA. We identified 139 patients with MINOCA and 142 patients with medically managed obstructive ACS (M-ACS). Multivariate regression analysis also identified female sex and cancer as independent predictors of MINOCA with odds ratios of 5.57 and 3.01, respectively. MINOCA patients were significantly less likely to receive cardioprotective medications at admission and discharge, specifically aspirin, beta-blockers, ACE-I and statins, compared to those with M-ACS. While mortality was higher among M-ACS patients (0.0% vs. 3.6%; p = 0.03), no significant differences were noted for composite NACE, heart failure, stroke and major bleeding. MINOCA patients have similar outcomes to M-ACS. Despite this, we noted a discrepancy in the use of cardioprotective medications. We also identified female sex and cancer were independent predictors of MINOCA. This may represent a missed opportunity to prevent adverse events among patients with MINOCA. Large, randomised trials are required to provide more definitive evidence.

Variability of discharge medical therapy for secondary prevention among patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) in the United States

BACKGROUND

Optimal medical therapy after myocardial infarction with nonobstructive coronary arteries (MINOCA; <50% stenosis) is uncertain. We evaluated variability in discharge prescription of angiotensin-converting enzyme inhibitors / angiotensin receptor blockers (ACEI/ARB) and beta-blockers (BB) to MINOCA patients between hospitals to assess physician equipoise about secondary prevention.

METHODS

Patients with MINOCA between 2007-2014 were identified in the NCDR Chest Pain-MI Registry. Those with prior revascularization or missing demographic, angiographic, or medication data were excluded. Analysis was limited to high-volume hospitals with ≥20 MINOCA total discharges. Discharge prescriptions for ACEI/ARB and BB after MINOCA were analyzed for each hospital. Clinical data on left ventricular ejection fraction (LVEF), glomerular filtration rate (GFR), and diabetes mellitus status were extracted to identify other indications for ACEI/ARB or BB.

RESULTS

Clinical data were available for 17,849 MINOCA patients, of whom 8,752 (49%) had LVEF <40%, GFR ≤60 mL/min, and/or diabetes. 5,913 patients without one of these indications for ACEI/ARB or BB were discharged from 156 high-volume hospitals. At discharge, ACEI/ARB was prescribed to between 16.0% and 88.8% of MINOCA patients (median 45.6%, IQR 38.0%-56.5%) and BB to between 28.0% and 97.5% (median 74.1%, IQR 64.7%-80.0%).

CONCLUSION

There is marked variability between hospitals in the proportions of patients receiving ACEI/ARB and BB after hospitalization for MINOCA, suggesting clinical equipoise about the routine use of these agents. Randomized clinical trials are necessary to establish the benefit of ACEI/ARB and BB to improve outcomes after MINOCA.

What an Interventionalist Needs to Know About MI with Non-obstructive Coronary Arteries

MI with non-obstructive coronary arteries (MINOCA) is caused by a heterogeneous group of vascular or myocardial disorders. MINOCA occurs in 5.15% of patients presenting with acute ST-segment elevation MI or non-ST segment elevation MI and prognosis is impaired. The diagnosis of MINOCA is made during coronary angiography following acute MI, where there is no stenosis ≥50% present in an infarct-related epicardial artery and no overt systemic aetiology for the presentation. Accurate diagnosis and subsequent management require the appropriate utilisation of intravascular imaging, coronary function testing and subsequent imaging to assess for myocardial disorders without coronary involvement. Although plaque-related MINOCA is currently managed with empirical secondary prevention strategies, there remains an unmet therapeutic need for targeted and evidence-based therapy for MINOCA patients and increased awareness of the recommended diagnostic pathway.