Systematic review of patients presenting with suspected myocardial infarction and nonobstructive coronary arteries

Characteristics and Prognosis of a Contemporary Cohort with Myocardial Infarction with Non-Obstructed Coronary Arteries (MINOCA) Presenting Different Patterns of Late Gadolinium Enhancements in Cardiac Magnetic Resonance Imaging

BACKGROUND

To analyze the characteristics and prognosis of a contemporary cohort of patients with myocardial infarction with non-obstructed coronaries (MINOCA) were referred for cardiac magnetic resonance (CMR) imaging, focusing on late gadolinium enhancement (LGE) patterns.

METHODS

We retrospectively examined and prospectively followed up with 135 patients (49 ± 21 years old, 48% female) undergoing CMR imaging due to a MINOCA diagnosis from 2014 to 2016. We grouped and analyzed the sample according to ischemic (focal or transmural) and non-ischemic LGE patterns. The primary outcome was cardiac-related death; the secondary outcome was a composite of cardiac-related rehospitalizations, the new occurrence of acute myocardial infarction (AMI), heart failure (HF), or arrhythmias.

RESULTS

CMR exams were performed after a median of 28 days from the acute event. One-third of the ischemic MINOCA were first managed as myocarditis, while CMR helped to adopt a different therapy regimen in 22% of patients (30/135). After a median follow-up of 2.3 years, more cardiac-related deaths occurred in the ischemic than non-ischemic group (2 vs. 1, p = 0.36), but it was not statistically significant. The ischemic group also experienced more cardiac-related-rehospitalizations (42%, p < 0.001). In a multivariable Cox regression model, dyslipidemia, reduced left ventricular ejection fraction, ST-elevation at the hospitalization, and the LGE transmural pattern were the independent predictors of cardiac-related rehospitalizations.

CONCLUSIONS

In a contemporary cohort of MINOCA patients who underwent CMR, ischemic and non-ischemic patterns had distinct features and outcomes. Among the MINOCA patients, CMR can identify patients at higher risk who require more aggressive therapeutic approached and strict follow-up.

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.

Cardiovascular and psychosocial risks among patients below age 50 with acute myocardial infarction

BACKGROUND

Despite improvements in the treatment and prevention of cardiovascular disease since the 1960s, the incidence of cardiovascular diseases among young people has remained the same for many years. This study aimed to compare the clinical and psychosocial attributes of young persons affected by myocardial infarction under the age of 50 years compared to middle-aged myocardial infarction patients 51-65 years old.

METHODS

Data from patients with a documented STEMI or NSTEMI elevated acute myocardial infarction in the age groups up to 65 years, were collected from cardiology clinics at three hospitals in southeast Sweden. The Stressheart study comprised a total of 213 acute myocardial infarction patients, of which n = 33 (15.5%) were under 50 years of age and n = 180 (84.5%) were middle-aged, (51-65 years). These acute myocardial infarction patients filled in a questionnaire at discharge from the hospital and further information through documentation of data in their medical records.

RESULTS

Blood pressure was significantly higher in young compared to middle-aged patients. For diastolic blood pressure (p = 0.003), systolic blood pressure (p = 0.028), and mean arterial pressure (p = 0.005). Young AMI patients had a higher (p = 0.030) body mass index (BMI) than the middle-aged. Young AMI patients were reported to be more stressed (p = 0.042), had more frequently experienced a serious life event the previous year (p = 0.029), and felt less energetic (p = 0.044) than middle-aged AMI patients.

CONCLUSIONS

This study revealed that persons under the age of 50 affected by acute myocardial infarction exhibit traditional cardiovascular risk factors like high blood pressure, and higher BMI, and were more exposed to some psychosocial risk factors. The risk profile of young persons under age 50 affected by AMI was in these respects more exaugurated than for middle-aged persons with AMI. This study underlines the importance of the early discovery of those at increased risk and encourages preventative actions to focus on both clinical and psychosocial risk factors.

Role of Intracoronary Imaging in Myocardial Infarction with Non-Obstructive Coronary Disease (MINOCA): A Review

Myocardial infarction with non-obstructive coronary artery disease occurs in 6% to 15% of all presentation of myocardial infarctions. The pathophysiologic mechanisms of MINOCA include epicardial vasospasm, coronary microvascular disorder, spontaneous coronary artery dissection, and coronary thrombus/embolism. The diagnosis is challenging, supported by intracoronary imaging with intravascular ultrasound (IVUS) and optical coherent tomography (OCT), coronary physiology testing, and cardiac magnetic resonance imaging (CMR). OCT is able to identify atherosclerotic causes of MINOCA (plaque erosion, plaque rupture, and calcified nodule) and nonatherosclerotic causes (spontaneous artery dissection, and spasm). In this review, we summarize the performance of the two intracoronary imaging modalities (IVUS and OCT) in MINOCA and discuss the importance of supplementing these modalities with CMR in order to drive target therapy.

Role of Cardiac Magnetic Resonance Imaging in the Evaluation of MINOCA

Myocardial infarction with Non Obstructive Coronary Arteries (MINOCA) is defined by patients presenting with signs and symptoms similar to acute myocardial infarction, but are found to have non-obstructive coronary arteries angiography. What was once considered a benign phenomenon, MINOCA has been proven to carry with it significant morbidity and worse mortality when compared to the general population. As the awareness for MINOCA has increased, guidelines have focused on this unique situation. Cardiac magnetic resonance (CMR) has proven to be an essential first step in the diagnosis of patients with suspected MINOCA. CMR has also been shown to be crucial when differentiating between MINOCA like presentations such as myocarditis, takotsubo and other forms of cardiomyopathy. The following review focuses on demographics of patients with MINOCA, their unique clinical presentation as well as the role of CMR in the evaluation of MINOCA.

Diagnostic and Prognostic Role of Cardiac Magnetic Resonance in MINOCA: Systematic Review and Meta-Analysis

BACKGROUND

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is common in current clinical practice. Cardiac magnetic resonance (CMR) plays an important role in its management and is increasingly recommended by all the current guidelines. However, the prognostic value of CMR in patients with MINOCA is still undetermined.

OBJECTIVES

The purpose of this study was to determine the diagnostic and prognostic value of CMR in the management of patients with MINOCA.

METHODS

A systematic review was performed to identify studies reporting the results of CMR findings in patients with MINOCA. Random effects models were used to determine the prevalence of different disease entities: myocarditis, myocardial infarction (MI), or takotsubo syndrome. Pooled odds ratios (ORs) and 95% CIs were calculated to evaluate the prognostic value of CMR diagnosis in the subgroup of studies that reported clinical outcomes.

RESULTS

A total of 26 studies comprising 3,624 patients were included. The mean age was 54.2 ± 5.3 years, and 56% were men. MINOCA was confirmed in only 22% (95% CI: 0.17-0.26) of the cases and 68% of patients with initial MINOCA were reclassified after the CMR assessment. The pooled prevalence of myocarditis was 31% (95% CI: 0.25-0.39), and takotsubo syndrome 10% (95% CI: 0.06-0.12). In a subgroup analysis of 5 studies (770 patients) that reported clinical outcomes, CMR diagnosis of confirmed MI was associated with an increased risk of major adverse cardiovascular events (pooled OR: 2.40; 95% CI: 1.60-3.59).

CONCLUSIONS

In patients with MINOCA, CMR has been demonstrated to add an important diagnostic and prognostic value, proving to be crucial for the diagnosis of this condition. Sixty-eight percent of patients with initial MINOCA were reclassified after the CMR evaluation. CMR-confirmed diagnosis of MINOCA was associated with an increased risk of major adverse cardiovascular events at follow-up.

How Does COVID-19 Affect the Heart?

PURPOSE OF REVIEW

Cardiac consequences occur in both acute COVID-19 and post-acute sequelae of COVID-19 (PASC). Here, we highlight the current understanding about COVID-19 cardiac effects, based upon clinical, imaging, autopsy, and molecular studies.

RECENT FINDINGS

COVID-19 cardiac effects are heterogeneous. Multiple, concurrent cardiac histopathologic findings have been detected on autopsies of COVID-19 non-survivors. Microthrombi and cardiomyocyte necrosis are commonly detected. Macrophages often infiltrate the heart at high density but without fulfilling histologic criteria for myocarditis. The high prevalences of microthrombi and inflammatory infiltrates in fatal COVID-19 raise the concern that recovered COVID-19 patients may have similar but subclinical cardiac pathology. Molecular studies suggest that SARS-CoV-2 infection of cardiac pericytes, dysregulated immunothrombosis, and pro-inflammatory and anti-fibrinolytic responses underlie COVID-19 cardiac pathology. The extent and nature by which mild COVID-19 affects the heart is unknown. Imaging and epidemiologic studies of recovered COVID-19 patients suggest that even mild illness confers increased risks of cardiac inflammation, cardiovascular disorders, and cardiovascular death. The mechanistic details of COVID-19 cardiac pathophysiology remain under active investigation. The ongoing evolution of SARS-CoV-2 variants and vast numbers of recovered COVID-19 patients portend a burgeoning global cardiovascular disease burden. Our ability to prevent and treat cardiovascular disease in the future will likely depend on comprehensive understanding of COVID-19 cardiac pathophysiologic phenotypes.

Acute Coronary Syndromes in Antiphospholipid Syndrome-above Suspicion: A Systematic Review

Antiphospholipid syndrome(APS) is an autoimmune disorder characterized clinically by vascular thrombosis and/or pregnancy morbidity, associated with persistently elevated titers of antiphospholipid antibodies on at least two measurements over 12 weeks apart. In this study, we conducted a systematic review of the literature utilizing the Pubmed platform, in order to acquire clinical information about acute coronary syndromes in patients with APS. The obtained articles were reviewed in order to register the clinical characteristics, the rate of occurrence, the prognosis and the therapeutic approach of these patients. APS should be considered in young patients with acute myocardial infarction, even in patients with normal coronary arteries. The pharmaceutical approach is mainly based on the vitamin K antagonists, and in certain occasions aspirin, without any definite guidelines on the subject. Further randomized clinical trials are imperative for a better understanding of the particular characteristics of this group of patients, so that a more complete therapeutic approach to be obtained.

Ventricular Septal Rupture Caused by Myocardial Infarction With Nonobstructive Coronary Arteries

Myocardial infarction with nonobstructive coronary arteries (MINOCA) has poor long-term cardiovascular outcomes, similar to myocardial infarction with conventional atherogenic coronary artery disease. However, MINOCA-related mechanical complications are rarely reported. We report a case of an octogenarian woman diagnosed with MINOCA-related ventricular septal rupture assessed by multimodal images, including autopsy findings. (Level of Difficulty: Intermediate.).

Assessment of a New Electrocardiographic Marker for the Diagnosis of Myocardial Infarction With Non-obstructive Coronary Arteries

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is clinically defined as myocardial infarction in the absence of obstructive atherosclerosis on coronary angiography. Diagnosis may require multiple diagnostic tools in addition to standard coronary angiography, including cardiac imaging or provocative tests, according to clinical suspicion. We assessed the usefulness of the DETERMINE (Defibrillators to Reduce Risk by Magnetic Resonance Imaging Evaluation) score for distinguishing patients with MINOCA from those with non-ST segment elevation myocardial infarction with obstructive coronary artery disease (NSTEMI-CAD) in a single-center observational study. The patients were divided into two groups according to coronary angiography findings. The study included 277 patients: 227 with NSTEMI-CAD and 50 with MINOCA. The DETERMINE score (6.1 ± 3.7 vs 1.9 ± 2.1, P<.001) was significantly higher in the NSTEMI-CAD than MINOCA group. Logistic regression analysis revealed that the DETERMINE score (OR=0.591, P<0.001) was an independent predictor of MINOCA. The incidence of diabetes mellitus and glucose levels were significantly higher in the NSTEMI-CAD group; however, ejection fraction was significantly higher in the MINOCA group (P<0.05). Our findings suggest that the DETERMINE score constitutes a simple and inexpensive tool for the assessment 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.

Characteristics and Long-term Mortality in Patients with ST-Segment Elevation Myocardial Infarction with Non-Obstructive Coronary Arteries (STE-MINOCA): A High Risk Cohort

Background

The prognosis of ST-segment elevation myocardial infarction with non-obstructive coronaries (STE-MINOCA) is largely unknown.

Methods

The objective of this study is to evaluate the prevalence, characteristics, and 5-year mortality of patients with STE-MINOCA compared to STEMI with coronary artery obstruction (STEMI-Obstruction) using a multicenter cohort of consecutive STEMI patients at 3 regional Midwest STEMI programs from 2003 to 2020. STE-MINOCA was defined based on (1) coronary stenosis < 60% by visual estimation, (2) ischemia with elevated troponin, and (3) no alternative diagnosis. STE-MINOCA was further classified based on American Heart Association (AHA) definition as AHA STE-MINOCA and AHA STE-MINOCA Mimicker.

Results

8,566 STEMI patients, including 420 (4.9%) STE-MINOCA (26.9% AHA STE-MINOCA and 73.1% AHA STE-MINOCA Mimicker) were followed for a median of 7.1 years. Compared to STEMI-Obstruction, STE-MINOCA were younger, more often female, had fewer cardiovascular risk factors, and were less likely to be discharged on cardiac medications. At five years, mortality was higher in STE-MINOCA compared with STEMI-Obstruction (18% vs. 15%, p=0.033). In propensity score-matched analysis, STE-MINOCA had a 1.4-fold (95% CI: 1.04-1.89, p=0.028) higher risk of 5-year all-cause mortality compared with STEMI-Obstruction. Furthermore, 5-year mortality risk was significantly higher in AHA STE-MINOCA Mimicker (19% vs. 15%, p=0.043) but similar in AHA STE-MINOCA (17% vs. 15%, p=0.42) compared with STEMI-Obstruction.

Conclusions

In this large multicenter STEMI cohort, nearly 5% of patients presented with STE-MINOCA. At five years, mortality approached 20% among patients with STE-MINOCA. Despite the lower risk profile, STE-MINOCA patients were at 40% higher risk of 5-year all-cause mortality compared with STEMI-Obstruction. Additionally, 5-year all-cause mortality risk was higher in AHA STE-MINOCA Mimicker but similar in AHA STE-MINOCA compared to STEMI-Obstruction.

Clinical Predictors and Prognosis of Myocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA) without ST-Segment Elevation in Older Adults

A non-neglectable percentage of patients with non-ST elevation myocardial infarction (NSTEMI) show non-obstructive coronary arteries (MINOCA). Specific data in older patients are scarce. We aimed to identify the clinical predictors of MINOCA in older patients admitted for NSTEMI and to explore the long-term prognosis of MINOCA. This was a single-center, observational, consecutive cohort study of older (≥70 years) patients admitted for NSTEMI between 2010 and 2014 who underwent coronary angiography. Univariate and multivariate Cox regression were performed to analyze the association of variables with MINOCA and all-cause mortality and with major adverse cardiac events (MACE), defined as a combined endpoint of all-cause mortality and nonfatal myocardial infarction and a combined endpoint of cardiovascular mortality, nonfatal myocardial infarction, and unplanned revascularization. The registry included 324 patients (mean age 78.8 ± 5.4 years), of which 71 (21.9%) were diagnosed with MINOCA. Predictors of MINOCA were female sex, left bundle branch block, pacemaker rhythm, chest pain at rest, peak troponin level, previous MI, Killip ≥2, and ST segment depression. Regarding prognosis, patients with obstructive coronary arteries (stenosis ≥50%) and the subgroup of MINOCA patients with plaques <50% had a similar prognosis; while MINOCA patients with angiographically smooth coronary arteries had a reduced risk of MACE. We conclude that the following: (1) in elderly patients admitted for NSTEMI, certain universally available clinical, electrocardiographic, and analytical variables are associated with the diagnosis of MINOCA; (2) elderly patients with MINOCA have a better prognosis than those with obstructive coronary arteries; however, only those with angiographically smooth coronary arteries have a reduced risk of all-cause mortality and MACE.

Sex differences in patients with acute coronary syndromes and non-obstructive coronary arteries: Presentation and outcome

BACKGROUND

A substantial number of patients present with a suspected ACS and non-obstructive coronary arteries; sex differences in these patients are not well understood. This study aims to evaluate the impact of sex on clinical presentation and outcome in patients with suspected acute coronary syndrome (ACS) and non-obstructive coronary arteries with a final diagnosis confirmed by cardiovascular magnetic resonance imaging (CMR).

METHODS

Consecutive patients with ACS and non-obstructive coronary arteries (n = 719) with an unclear cause from a single tertiary centre who were referred for CMR were included. The primary endpoint was all-cause mortality.

RESULTS

CMR was performed at a median time of 30 days after presentation and identified a diagnosis in 74% of patients. All-cause mortality was 9.5% over a median follow up of 4.9 years, with no significant difference between sexes (8.8% versus 10.1%; p = 0.456). Men were more likely to have non-ischaemic aetiology on CMR than women (55% v 41%, p < 0.001), but were equally likely to have an ischaemic cause (25% v 27%, p = 0.462). Age group (HR 1.58, p < 0.001) and LV ejection fraction (HR 0.98, p = 0.023) were independent predictors of mortality.

CONCLUSIONS

There is no difference in all-cause mortality between sexes in patients presenting with suspected ACS and non-obstructive coronary arteries.

Prognostic implication of coronary slow flow assessed by cTFC in patients with myocardial infarction with Non-obstructive coronary arteries

BACKGROUND

Coronary slow flow (CSF) is common and linked to worse cardiovascular events and life-threatening arrhythmias. However, the clinical implication of CSF among myocardial infarction with the non-obstructive coronary artery (MINOCA) has never been studied. We aimed to evaluate the impact of CSF on the MINOCA population.

METHODS

Patients diagnosed with MINOCA were consecutively selected. The corrected TIMI frame count (cTFC) was used to evaluate the coronary flow. CSF was defined as cTFC greater than 27 frames per second (FPS) in any of the three coronary arteries. Major adverse cardiovascular events (MACE) are the primary endpoint. Cox regression analysis was used to evaluate the association between CSF and MACE.

RESULTS

A total of 158 patients with MINOCA were enrolled, of which 54 (34.2%) patients had CSF. Forty incidents of MACE occurred during the median 28 months of follow-up. The MACE incidence was higher among patients who presented with CSF than the normal coronary flow patients (35.2% vs. 20.2%, p = 0.040). In the Kaplan-Meier analysis, CSF patients had significantly higher rates of MACE (log-rank P = 0.034). Multivariate Cox regression analysis showed that CSF was an independent predictor linked to an increased hazard of MACE (adjusted HR, 2.76; 95% CI, 1.34-5.67; P = 0.006).

CONCLUSION

The presence of CSF is associated with a higher risk of adverse events and is an independent predictor of clinical outcomes among patients with MINOCA. This result suggests that CSF might serve as a robust tool to stratify MINOCA patients.

Nonobstructive coronary atherosclerosis is associated with adverse prognosis among patients diagnosed with myocardial infarction without obstructive coronary arteries

BACKGROUND AND AIMS

The prognostic impact of nonobstructive coronary artery disease (CAD), as opposed to normal coronary arteries, on long-term outcomes of patients with myocardial infarction with no obstructive coronary arteries (MINOCA) is unclear. We aimed to address the association between nonobstructive-CAD and major adverse events (MAE) following MINOCA.

METHODS

We conducted a retrospective cohort study of consecutive MINOCA patients admitted to a large referral medical center between 2005 and 2018. Patients were classified according to coronary angiography as having either normal-coronaries or nonobstructive-CAD. The primary outcome was MAE, defined as the composite of all-cause mortality and recurrent acute coronary syndrome (ACS).

RESULTS

Of the 1544 MINOCA patients, 651 (42%) had normal coronaries, and 893 (58%) had CAD. The mean age was 61.2 ± 12.6 years, and 710 (46%) were females. Nonobstructive-CAD patients were older and less likely to be females, with higher rates of diabetes, hypertension, dyslipidemia, atrial fibrillation, and chronic renal-failure (p < 0.05). At a median follow-up of 7 years, MAE occurred in 203 (23%) patients and 67 (10%) patients in the nonobstructive-CAD and normal-coronaries groups, respectively (p < 0.01). In multivariable models, nonobstructive -CAD was significantly associated with long-term MAE [adjusted-hazard-ratio (aHR):1.67, 95% confidence-interval (95%CI):1.25-2.23; p < 0.001]. Other factors associated with a higher MAE-risk were older-age (aHR:1.05,95%CI:1.03-1.06; p < 0.001) and left ventricular ejection-fraction<40% (aHR:3.04,95%CI:2.03-4.57; p < 0.001), while female-sex (aHR:0.72, 95%CI: 0.56-0.94; p=0.014) and sinus rhythm at presentation (aHR:0.66, 95%CI: 0.44-0.98; p=0.041) were associated with lower MAE-risk.

CONCLUSIONS

In MINOCA, nonobstructive-CAD is independently associated with a higher MAE-risk than normal-coronaries. This finding may promote risk-stratification of patients with nonobstructive-CAD-MINOCA who require tighter medical follow-up and treatment optimization.

Role of cardiac magnetic resonance in MINOCA of unclear etiology: a case report of a suspicious paradoxical coronary embolism

The acronym MINOCA (Myocardial Infarction with Non-Obstructive Coronary Arteries) refers to myocardial infarction with normal or near-normal coronary arteries on invasive angiography. The broad spectrum of pathological mechanisms responsible for myocardial injury in MINOCA makes defining the exact underlying etiology challenging. We report the uncommon case of an acute myocardial infarction with normal coronary arteries suggestive of MINOCA caused by paradoxical coronary embolism due to a wide right-to-left shunting through a patent fossa ovalis. Integrated multimodality imaging diagnostic work-up, including cardiac magnetic resonance, transesophageal contrast echocardiography, and transcranial contrast Doppler, has been crucial for identifying the most likely mechanism underlying MINOCA.

MINOCA mimic: Type 2 myocardial infarction due to severe aortic stenosis complicated by cardiogenic shock

Acute myocardial infarction without significant obstructive coronary disease presents a challenging clinical entity that requires timely intervention. The term myocardial infarction with nonobstructive coronary arteries (MINOCA) describes a working diagnosis attributed to varying etiologies in patients with a presumed ischemic cardiac condition. Several overlapping etiologies can be classified as type 2 myocardial infarction (MI). The 2019 AHA statement established diagnostic criteria and clarified the associated confusion, aiding in appropriate diagnosis. In this report, we present a case of demand-ischemia MINOCA and cardiogenic shock in a patient with severe aortic stenosis (AS).

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.

Antiplatelet therapy in patients with myocardial infarction with non-obstructive coronary arteries: A clinical perspective

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a heterogeneous group of diseases with different pathological mechanisms, and it is uncertain whether the classical secondary prevention and treatment strategies for myocardial infarction in obstructive coronary artery disease (MI-CAD) are appropriate for patients with MINOCA. Therefore the choice of antiplatelet agents and the therapeutic effect may vary depending on the etiology and pathophysiological mechanisms of MINOCA. This requires our clinical and scientific researchers to properly design prospective studies to explore the pathophysiology of MINOCA and its corresponding etiology in greater depth, so as to understand the effectiveness and safety of medical therapies for different etiologies of MINOCA. Although the current observational studies do not show an obvious beneficial effect of antiplatelet therapy on MINOCA. We are eager to conduct specific prospective randomized controlled trials of antiplatelet agents to assess the specificity, efficacy and safety of different types of antiplatelet agents in patients with MINOCA of different etiologies.

Long-term outcomes and predictors of patients with ST elevated versus non-ST elevated myocardial infarctions in non-obstructive coronary arteries: a retrospective study in Northern China

Background

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a heterogeneous disease entity with diverse etiologies and no uniform treatment protocols. Patients with MINOCA can be clinically classified into two groups based on whether they have an ST-segment elevation (STE) or non-ST segment elevation (NSTE), based on electrocardiogram (ECG) results, whose clinical prognosis is unclear. This study aimed to compare the outcomes and predictors of patients with STE and NSTE in the MINOCA population.

Methods

We collected the data for 196 patients with MINOCA (115 with STE and 81 with NSTE) in China. Clinical characteristics, prognoses, and predictors of major adverse cardiovascular events (MACE) were analyzed during the follow-up of all patients.

Results

The proportion of patients with STE was greater than that with NSTE in the MINOCA population. Patients with NSTE were older and had a higher incidence of hypertension. No differences were observed in the outcomes between the STE and NSTE groups during a median follow-up period of 49 (37,46) months. No significant differences were observed in those with MACE (24.35% vs 22.22%, P = 0.73) and those without MACE. The multivariable predictors of MACE in the NSTE groups were Killip grades ≥ 2 (HR 9.035, CI 95% [1.657-49.263], P = 0.011), reduced use of β-blockers during hospitalization (HR 0.238, CI 95% [0.072-0.788], P = 0.019), and higher levels of low-density lipoprotein cholesterol (LDL-C) (HR 2.267, CI 95% [1.008-5.097], P = 0.048); the reduced use of β-blockers during hospitalization was the only independent risk factor of MACE in the STE group.

Conclusions

There were differences between the clinical characteristics of patients with STE and NSTE in the MINOCA population, even though outcomes during follow-up were similar. Independent risk factors for major adverse cardiac events were not identical in the STE and NSTE groups, which could be attributable to the differences in disease pathogenesis.

Biomarker Concentrations and Their Temporal Changes in Patients With Myocardial Infarction and Nonobstructive Compared With Obstructive Coronary Arteries: Results From the PLATO Trial

Background The pathobiology of myocardial infarction (MI) with nonobstructive coronary arteries (MINOCA) is often uncertain. Investigating biomarker concentrations and their changes may offer novel pathophysiological insights. Methods and Results In this post hoc study of the PLATO (Platelet Inhibition and Patient Outcomes) trial, concentrations of hs-cTnT (high-sensitivity cardiac troponin T), NT-proBNP (N-terminal pro-B-type natriuretic peptide), hs-CRP (high-sensitivity C-reactive protein), and GDF-15 (growth differentiation factor 15) were measured in patients with MINOCA at baseline (n=554) and at 1-month follow-up (n=107). For comparisons, biomarkers were also measured in patients with MI with obstructive (stenosis ≥50%) coronary artery disease (baseline: n=11 106; follow-up: n=2755]). Adjusted linear regression models were used to compare concentrations and their short- and long-term changes. The adjusted geometric mean ratios (GMRs) in patients with MINOCA (median age, 61 years; 50.4% women) indicated lower hs-cTnT (GMR, 0.77 [95% CI, 0.68-0.88]) but higher hs-CRP (GMR, 1.21 [95% CI, 1.08-1.37]) and GDF-15 concentrations (GMR, 1.06 [95% CI, 1.02-1.11]) at baseline compared with patients with MI with obstructive coronary artery disease, whereas NT-proBNP concentrations were similar. Temporal decreases in hs-cTnT, NT-proBNP, and hs-CRP concentrations until 1-month follow-up were more pronounced in patients with MINOCA. At follow-up, patients with MINOCA had lower concentrations of hs-cTnT (GMR, 0.71 [95% CI, 0.60-0.84]), NT-proBNP (GMR, 0.45 [95% CI, 0.36-0.56]), and hs-CRP (GMR, 0.68 [95% CI, 0.53-0.86]). One-month GDF-15 concentrations were similar between both groups with MI. Conclusions Biomarker concentrations suggest greater initial inflammatory activity, similar degree of myocardial dysfunction, and less pronounced myocardial injury during the acute phase of MINOCA compared with MI with obstructive coronary artery disease but also faster myocardial recovery. Registration URL: http://www.clinicaltrials.gov; Unique identifier: NCT00391872.

Clinical and imaging characteristics of cardiac magnetic resonance presenting with myocardial infarction with non-obstructive coronary arteries in China

BACKGROUND

The characteristics are still unclear due to lack of systematic research on patients with myocardial infarction non-obstructive coronary arteries (MINOCA) in China. This study aimed to explore the clinical and imaging features of MINOCA patients.

METHODS

The patients who were diagnosed as suspected MI were studied. Cardiac magnetic resonance (CMR) was performed after coronary angiography or coronary computed tomographic angiography examination within one week. Myocardial infarction (MI) was determined by late gadolinium enhancement CMR.The patients with MI were divided into MINOCA and MICAD group according to whether the degree of coronary stenosis was greater than 50%. Cardiac function and imaging characteristics between the two groups were analyzed.

RESULTS

21 patients with MINOCA and 30 patients with myocardial infarction with obstructive coronary artery disease (MICAD) were analyzed. MINOCA patients were younger, and the electrocardiogram was commonly featured by non-ST-elevation. The parameters of left ventricular function were significantly different between the two groups including left ventricular ejection fraction, stroke volume, cardiac output, myocardial mass, and peak ejection rate (P < 0.05). Besides, MINOCA patients had smaller area of MI, less score of transmural extent, fewer involved segments. Furthermore, the transmural extent of MI in MINOCA patients was mainly grade I, that is, most of them were subendocardial MI, which was significantly negatively correlated with the amount of first-pass perfusion.

CONCLUSIONS

The clinical characteristics combined with imaging features of CMR may be effective to evaluate the cardiac function in order to make clinical decision for MINOCA patients in China.

Underlying Causes of Myocardial Infarction with Nonobstructive Coronary Arteries: Optical Coherence Tomography and Cardiac Magnetic Resonance Imaging Pilot Study

BACKGROUND

Scientific statements recommend multimodality imaging in myocardial infarction with non-obstructive coronary arteries (MINOCA) to define the underlying cause.

AIM

We evaluated the diagnostic yield of intravascular optical coherence tomography (OCT) and cardiac magnetic resonance (CMR) in the MINOCA setting.

METHODS

In this prospective, single center, observational pilot study, we enrolled patients with MINOCA without previous coronary interventions. All patients underwent three vessel OCT, followed by CMR. Imaging results were combined to determine the mechanism of MINOCA, when possible.

RESULTS

We enrolled 10 patients in this pilot study. Women constituted 50% of the analyzed population. The mean age of patients was 52 years. ST-segment elevation was found in 30% of patients. A possible culprit lesion was identified by OCT in 70% of participants, most commonly plaque rupture or erosion. An ischemic pattern of CMR abnormalities was identified in 70% of participants. Myocarditis and Tako-Tsubo were identified in 30%. A cause of MINOCA was identified in all patients using multimodality imaging, while using OCT alone identification occurred in only 70% of patients.

CONCLUSION

In this pilot study, multimodality imaging with OCT and CMR identified potential mechanisms in all patients with a diagnosis of MINOCA, and it has the potential to guide medical therapy for secondary prevention.

Acute clinical presentation of nonischemic cardiomyopathies: early detection by cardiovascular magnetic resonance

Nonischemic cardiomyopathies include a wide range of dilated, hypertrophic and arrhythmogenic heart muscle disorders, not explained by coronary artery disease, hypertension, valvular or congenital heart disease. Advances in medical treatments and the availability of implantable cardioverter defibrillators to prevent sudden cardiac death have allowed a substantial increase in the survival of affected individuals, thus making early diagnosis and tailored treatment mandatory. The characterization of cardiomyopathies has received a great boost from the recent advances in cardiovascular magnetic resonance (CMR) imaging, which, to date, represents the gold standard for noninvasive assessment of cardiac morphology, function and myocardial tissue changes. An acute clinical presentation has been reported in a nonnegligible proportion of patients with nonischemic cardiomyopathies, usually complaining of acute chest pain, worsening dyspnoea or palpitations; 'hot phases' of cardiomyopathies are characterized by a dynamic rise in high-sensitivity troponin, myocardial oedema on CMR, arrhythmic instability, and by an increased long-term risk of adverse remodelling, progression of myocardial fibrosis, heart failure and malignant ventricular arrhythmias. Prompt recognition of 'hot phases' of nonischemic cardiomyopathies is of utmost importance to start an early, individualized treatment in these high-risk patients. On the one hand, CMR represents the gold standard imaging technique to detect early and typical signs of ongoing myocardial remodelling in patients presenting with a 'hot phase' nonischemic cardiomyopathy, including myocardial oedema, perfusion abnormalities and pathological mapping values. On the other hand, CMR allows the differential diagnosis of other acute heart conditions, such as acute coronary syndromes, takotsubo syndrome, myocarditis, pericarditis and sarcoidosis. This review provides a deep overview of standard and novel CMR techniques to detect 'hot phases' of cardiomyopathies, as well as their clinical and prognostic utility.

Image Quality of Submillimeter High-Spatial-Resolution 2D Late Gadolinium-enhanced Images in Cardiac MRI: A Feasibility Study

Purpose

To evaluate the image quality of high-spatial-resolution two-dimensional (2D) late gadolinium enhancement (LGE) cardiac MRI compared with conventional normal-resolution LGE MRI.

Materials and Methods

This prospective study included participants suspected of having cardiomyopathy who underwent cardiac MRI between March 2021 and December 2021. Normal-resolution and high-resolution 2D LGE sequences (inversion recovery [IR] and phase-sensitive inversion recovery [PSIR]) were performed at 3 T. Resolution was compared between normal-resolution and high-resolution images obtained in a quality assurance phantom. In vivo image quality and resolution were evaluated qualitatively using a five-point scoring system. Receiver operating characteristic curve analysis was used for LGE detection performance. Border sharpness was assessed with profile curve measurement. The contrast-to-noise ratio (CNR) between hyperenhancement and remote myocardium and LGE detection performance were calculated using normal-resolution IR images as the reference.

Results

In total, 120 participants were evaluated (mean age, 56 years ± 17 [SD]; 72 men). Features smaller than 1 mm were detectable only on high-resolution images of the phantom. In vivo, the image resolution score with high-resolution LGE was 4.14-4.24, which was higher than the normal-resolution LGE reference score of 2.99 (P < .05). Border sharpness was higher in high-resolution images (P < .001). Receiver operating characteristic curve analysis revealed no evidence of a difference in LGE detection between normal-resolution and high-resolution images. There was also no evidence of a change in CNR of LGE in IR and PSIR magnitude compared with reference images.

Conclusion

Comparison of image quality in 2D high-resolution and normal-resolution LGE cardiac MRI demonstrated the highest resolution for high-resolution IR and high-resolution PSIR magnitude sequences.Keywords: Cartilage Imaging, MRI, Cardiac, Heart, Imaging Sequences, Comparative Studies Supplemental material is available for this article. © RSNA, 2022.

Relationships between indicators of prothrombotic activity and coronary microvascular dysfunction in patients with myocardial infarction with obstructive and non-obstructive coronary artery disease

The relationship between prothrombotic activity and coronary microvascular dysfunction (MVD) is limited. This study aimed to perform a comparative analysis of the relationship between prothrombotic activity and MVD in patients with myocardial infarction without obstructive coronary artery disease (MINOCA) and myocardial infarction with obstructive coronary artery disease (MI-CAD).

MATERIAL AND METHODS

A total of 37 patients were enrolled in the study; the main group included 16 MINOCA patients, and 21 MI-CAD patients were included in the control group. Blood samples for protein C, antithrombin, WF, plasminogen, and homocysteine were performed on the 4th ± 1 day of admission. CZT-SPECT data were used to determine the standard indices of myocardial perfusion dis-orders (SSS, SRS, and SDS), as well as stress and rest myocardial blood flow (MBF), myocardial flow reserve (MFR), and difference flows (DF). MVD was defined as MFR (≤ 1.91 ml/min); coronary slow flow (CSF) was defined as corrected TIMI frame count (21 ± 3).

RESULTS

We performed a step-by-step analysis of prothrombotic activity of the hemostasis system in binary logistic regression for MINOCA patients to identify factors associated with MVD (MFR ≤ 1.91 ml/min). A predictive model was developed to estimate the probability of reduced MFR. A low MFR is related to only plasminogen in MINOCA patients, whereas only wall motion score index (WMSI) in MI-CAD group was associated with a low MFR.

CONCLUSION

This small-scale study revealed the relationship between indicators of prothrombotic activity and MVD. The key factors that affect MVD in MINOCA patients was plasminogen, whereas, in patients with MI-CAD, WMSI was the key factor. Measurements of MVD may enhance the risk stratification and facilitate future targeting of adjunctive antithrombotic therapies in MINOCA and MI-CAD patients.

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).

[Cardiac magnetic resonance imaging and coronary optical coherence tomography : Acquisition techniques, interpretation and integration in diagnostic algorithms for MINOCA]

MINOCA is a heterogeneous entity with many possible etiologies that need to be clarified to optimize therapeutic interventions. Common causes include plaque disruption, plaque erosion, spontaneous coronary artery dissection, coronary artery spasm, coronary thromboembolism. Most of the time, coronary angiography is inadequate to obtain the proper identification of these underlying pathophysiological mechanisms. Within this context, myocardial tissue characterization with magnetic resonance imaging is key investigation to assess and locate recent myocardial infarctions and to exclude differential diagnostics such as myocarditis or takotsubo cardiomyopathy. In addition, optical coherence tomography is a powerful tool to visualize coronary intraluminal and superficial coronary artery structures in detail including the detection of plaque disruption signs, thrombus or dissections. The use of appropriate diagnostic algorithms combining both OCT and CMR seems to provide a clear substrate or diagnosis to many of the cases. This narrative review aims to expose both imaging modalities focusing on their contributions in the setting of MINOCA.

Association Between Breast Arterial Calcification on Mammography and Coronary Artery Disease: A Systematic Review and Meta-Analysis

Background: Breast arterial calcification (BAC), which may be detected during screening mammography, is hypothesized to be a noninvasive imaging marker that may enhance cardiovascular risk assessment. Materials and Methods: In this systematic review and meta-analysis, we sought to assess the association between BAC and coronary artery disease (CAD) by conducting a meta-analysis. We conducted a literature search of PubMed, Scopus, Cochrane library, ClinicalTrials.gov, and conference proceedings, from inception through December 24, 2019. The outcome of interest was the presence of CAD in patients with BAC. This was reported as crude and adjusted odds ratio (OR). Results: A total of 18 studies comprising 33,494 women (mean age of 60.8 ± 3.7 years, 25% with diabetes, 57% with hypertension, and 21% with history of tobacco smoking) were included in the current meta-analysis. The prevalence of BAC among study participants was 10%. There was a statistically significant association between BAC and CAD (unadjusted OR 2.14; 95% confidence interval [CI] 1.63-2.81, p < 0.001, I2 = 76.5%). Moreover, adjusted estimates were available from 10 studies and BAC was an independent predictor of CAD (OR 2.39; 95% CI 1.68-3.41, p < 0.001, I2 = 61.7%). In the meta-regression analysis, covariates included year of publication, age, hypertension, diabetes mellitus, and history of tobacco smoking. None of these study covariates explained the heterogeneity across studies. Conclusions: BAC detected as part of screening mammography is a promising noninvasive imaging marker that may enhance CAD risk prediction in women. The clinical value of BAC for cardiovascular risk stratification merits further evaluation in large prospective studies.

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.

Imaging of heart disease in women: review and case presentation

Cardiovascular diseases (CVD) remain the leading cause of mortality worldwide. Although major diagnostic and therapeutic advances have significantly improved the prognosis of patients with CVD in the past decades, these advances have less benefited women than age-matched men. Noninvasive cardiac imaging plays a key role in the diagnosis of CVD. Despite shared imaging features and strategies between both sexes, there are critical sex disparities that warrant careful consideration, related to the selection of the most suited imaging techniques, to technical limitations, and to specific diseases that are overrepresented in the female population. Taking these sex disparities into consideration holds promise to improve management and alleviate the burden of CVD in women. In this review, we summarize the specific features of cardiac imaging in four of the most common presentations of CVD in the female population including coronary artery disease, heart failure, pregnancy complications, and heart disease in oncology, thereby highlighting contemporary strengths and limitations. We further propose diagnostic algorithms tailored to women that might help in selecting the most appropriate imaging modality.

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.

[MINOCA-myocardial infarction with nonobstructive coronary arteries]

BACKGROUND

Myocardial infarction with nonobstructive coronary arteries (MINOCA) accounts for 5-10% of all presentations of acute myocardial infarction.

OBJECTIVES

To outline the role of cardiovascular magnetic resonance (CMR) in patients with suspected MINOCA.

MATERIALS AND METHODS

Current guidelines for the use of CMR in suspected MINOCA are summarized. Clinical cases with typical CMR findings are presented.

RESULTS

In 2019, the American Heart Association published a revised definition of the term MINOCA, which was recently adopted in the European Society of Cardiology 2020 guidelines on acute coronary syndromes without persistent ST-segment elevation (NSTE-ACS). The guidelines indicate that a CMR is recommended (class 1B) in all MINOCA cases with no obvious cause.

CONCLUSION

The major strength of CMR imaging is to differentiate nonischemic from ischemic etiologies of myocardial injury. This makes CMR the most important noninvasive diagnostic tool for the differential diagnosis of patients with suspected MINOCA.

Contemporary Risk Stratification of Acute Coronary Syndrome

Chest pain is one of the most common presenting concerns of patients seeking care in the emergency department, and the underlying etiology can range from acute coronary syndrome to various other non-cardiac causes. Initial evaluation should focus on characterizing symptoms and identifying risk factors, but further risk stratification using clinical decision pathways and biomarkers (cardiac troponin) is essential. The 2021 American Heart Association/American College of Cardiology guidelines for the evaluation and diagnosis of chest pain represent the first ever guidelines for the evaluation of patients with acute chest pain. The contemporary risk stratification methods described in these guidelines allow for the identification of patient subgroups: patients who do not require further testing, patients who should proceed directly to the cath lab, and patients who will benefit from further anatomic or functional testing. In this review, we describe contemporary risk stratification methods for acute coronary syndrome and summarize the recommendations put forth by the guidelines.

Cardiac MRI in myocardial infarction without obstructive coronary artery disease (MINOCA) helps arrive at correct diagnosis - A case report and discussion

Myocardial infarction without obstructive coronary artery disease (MINOCA) is a common condition with estimated prevalence of 5 to 15 %. It is not a benign condition and diagnosing the exact underlying etiology can be challenging, but it is important to ensure appropriate management of MINOCA patients. Cardiac magnetic resonance imaging (CMRI) can be a valuable and non-invasive test to identify the underlying etiology, as well as to risk-stratify such patients. Both the European Society of Cardiology and the American Heart Association recommend CMRI in diagnostic work up of MINOCA patients. We report a case of an 83-year-old man who presented to the emergency department with atypical chest pain but had significantly elevated cardiac troponin levels, with non-obstructive coronary artery disease on left heart catheterization. Subsequent CMRI led to the diagnosis of acute myocarditis. He was medically managed with good clinical outcomes. We discuss this case in detail and highlight the role of CMRI in MINOCA patients. As our understanding of troponin elevation and its various mechanisms continues to evolve, cardiac MRI has a significant role in diagnosis and management, as demonstrated in our case.

Learning objectives

1.Illustrate the clinical relevance and diagnosis of myocardial infarction without obstructive coronary artery disease (MINOCA).2.Explain the role of cardiac magnetic resonance imaging in diagnosis and management of MINOCA.

Multimodality Imaging in the Detection of Ischemic Heart Disease in Women

Women with coronary artery disease tend to have a worse short and long-term prognosis relative to men and the incidence of atherosclerotic cardiovascular disease is increasing. Women are less likely to present with classic anginal symptoms when compared with men and more likely to be misdiagnosed. Several non-invasive imaging modalities are available for diagnosing ischemic heart disease in women and many of these modalities can also assist with prognostication and help to guide management. Selection of the optimal imaging modality to evaluate women with possible ischemic heart disease is a scenario which clinicians often encounter. Earlier modalities such as exercise treadmill testing demonstrate significant performance variation in men and women, while newer modalities such as coronary CT angiography, myocardial perfusion imaging and cardiac magnetic resonance imaging are highly specific and sensitive for the detection of ischemia and coronary artery disease with greater parity between sexes. Individual factors, availability, diagnostic performance, and female-specific considerations such as pregnancy status may influence the decision to select one modality over another. Emerging techniques such as strain rate imaging, CT-myocardial perfusion imaging and cardiac magnetic resonance imaging present additional options for diagnosing ischemia and coronary microvascular dysfunction.

Outcomes after coronary angiography for unstable angina compared to stable angina, myocardial infarction and an asymptomatic general population

Background

The outcomes of real-world unstable angina (UA) in the high-sensitivity troponin era are unclear. We aimed to investigate the outcomes of UA referred to coronary angiography compared to stable angina (SA), non-ST-segment elevation myocardial infarction (NSTEMI), STEMI and a general population.

Methods

We included the 9,694 patients with no prior coronary artery disease (CAD) referred to invasive or CT coronary angiography from 2013 to 2018 in Northern Norway (51% SA, 12% UA, 23% NSTEMI and 14% STEMI), and 11,959 asymptomatic individuals recruited from the Tromsø Study. We used Cox models to estimate the hazard ratios (HR) for all-cause mortality and major adverse cardiovascular events (MACE), defined as cardiovascular death, MI or obstructive CAD.

Results

The median follow-up time was 2.8 years. The incidence rate of death was 8.5 per 1000 person-years (95 % confidence interval [CI] 8.0-9.0) in the general population, 9.7 (95 % CI 8.3-11.5) in SA, 14.9 (95 % CI 11.4-19.6) in UA, 29.7 (95 % CI 25.6-34.3) in NSTEMI and 36.5 (95 % CI 30.9-43.2) in STEMI. In multivariable adjusted analyses, compared with UA, SA had a 38 % lower risk of death and a non-significant lower risk of MACE (HR 0.62, 95 % CI 0.44-0.89; HR 0.86, 95 % CI 0.66-1.11). NSTEMI had a 2.4-fold higher risk of death (HR 2.39, 95 % CI 1.38-4.14) and a 1.6-fold higher risk of MACE (HR 1.62, 95 % CI 1.11-2.38) compared tox UA during the first year after coronary angiography, but a similar risk thereafter. There was no difference in the risk of death for UA with non-obstructive CAD and obstructive CAD (HR 0.78, 95 % CI 0.39-1.57).

Conclusion

UA had a higher risk of death but a similar risk of MACE compared to SA and a lower 1-year risk of death and MACE compared to NSTEMI.

Identification of subclinical myocardial dysfunction by Speckle Tracking Imaging in patients with myocardial infarction with non-occlusive coronary arteries (MINOCA)

PURPOSE

The objective of this study was to investigate subclinical left ventricular dysfunction in patients diagnosed with myocardial infarction with non-occlusive coronary arteries (MINOCA).

METHODS

Thirty-five patients with MINOCA (average age 54.26 ± 12.24 years) and thirty-five patients with ischemia with non-obstructed coronary artery disease (INOCA) (average age 55.20 ± 8.36 years) were enrolled in the study. All clinical conditions that could affect left ventricular functions were considered exclusion criteria. Echocardiographic studies were conducted in the patient and control groups in the left lateral decubitus position using a medical ultrasound device (EPIQ 7, Philips Medical System, USA). The left ventricle was examined longitudinally with apical images of chamber 4-3-2 using the available software (QLAB 6.0).

RESULTS

There were no differences in age, blood pressure level, baseline echocardiogram measurements, and tissue Doppler parameters between the two groups. In two-dimensional speckle tracking echocardiography (2D-STE) measurements, left ventricular longitudinal strain and strain rate in systole, early and late diastole from apical 4-3-2 chamber and global measurements of each parameter were significantly decreased in the MINOCA group compared to the INOCA group (p < 0.05). A significant negative correlation was observed between the global longitudinal strain rate and the troponin I in the MINOCA patients group (r=-0.43 p = 0.009).

CONCLUSIONS

Our study showed that while standard echocardiographic parameters for patients diagnosed with MINOCA were normal, their left ventricular systolic and diastolic functions were reduced by the 2D-STE method.

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.

Association of endothelial glycocalyx shedding and coronary microcirculation assessed by an angiography-derived index of microcirculatory resistance in patients with suspected coronary artery disease

Background

The endothelial glycocalyx (EG) is essential for maintaining microvascular homeostasis. However, the relationship between the EG and coronary microcirculation remains to be elucidated. One of the main components of EG is syndecan-1, and its shedding has been claimed to represent the state of the EG. In this study, we aimed to analyze the association between syndecan-1 and the coronary microcirculation.

Methods

We enrolled suspected coronary artery disease (CAD) patients who consecutively underwent coronary angiography (CAG) and angiography-based analysis of physiological indices in the left anterior descending artery (LAD). Serum syndecan-1 was measured by enzyme-linked immunosorbent assay (ELISA). The coronary microcirculation was evaluated by the presence of coronary microvascular dysfunction (CMD) and an impaired microvascular vasodilatory capacity (IMVC), which were quantified by an angiography-derived index of microcirculatory resistance (IMRangio) in the maximum hyperemic state (H-IMRangio) induced by adenosine triphosphate and the ratio (RRRangio) of IMRangio in the non-hyperemic phase to H-IMRangio, respectively.

Results

A total of 528 patients were enrolled in this study. There was no difference in epicardial coronary complexity between patients with high syndecan-1 (HSG) and low syndecan-1 (LSG) levels grouped by the median concentration of syndecan-1 (SYNTAX: 7[3, 10] vs. 9[4, 12], P = 0.15). However, H-IMRangio and RRRangio were different between the LSG and HSG groups (H-IMRangio: 23.64 ± 6.28 vs. 27.67 ± 5.59, P < 0.01; RRRangio: 1.74[1.46, 2.08] vs. 1.55[1.34, 1.72], P < 0.01). Patients with CMD (H-IMRangio > 25) and patients with IMVC (RRRangio below the median value) both had higher syndecan-1 levels (CMD: 86.44 ± 54.15 vs. 55.2 ± 43.72, P < 0.01; IMVC: 83.86 ± 55.41 vs. 59.68 ± 45.06, P < 0.01). After adjustment for confounding factors, HSG remained associated with the presence of CMD and IMVC (CMD: odds ratio [OR]: 2.769, P < 0.01; IMVC: OR: 1.908, P < 0.01).

Conclusion

High levels of syndecan-1 are independently associated with the presence of CMD and IMVC among patients with suspected CAD.

Utility of cardiac magnetic resonance in the diagnosis of suspected “MINOCA”: a case series and literature review

Myocardial infarction with nonobstructive coronary artery (MINOCA) is a common condition in clinical practice with multiple specific causes, such as plaque rupture, plaque erosion, and epicardial coronary vasospasm. There must be an ischemic mechanism responsible for the myocyte injury and an exclusion of nonischemic mechanisms that can mimic myocardial infarction, and then a diagnosis of MINOCA can be made. Cardiac magnetic resonance (CMR) plays an essential role in the diagnosis and differential diagnosis of MINOCA, which cannot only exclude myocarditis, Takotsubo syndrome, and cardiomyopathies, but also provide imaging confirmation of acute myocardial infarction. In this study, we presented 2 typical cases with the clinical presentation of acute myocardial infarction but normal or nonobstructive epicardial coronary arteries. Further CMR examinations showed different patterns of late gadolinium enhancement (LGE) in these 2 cases, one case with subendocardial LGE of the anterolateral wall and the other one with subepicardial LGE of the lateral wall, which indicated 2 different mechanisms for the myocyte injury. Subsequently, these 2 patients received different treatment regimens and were discharged with improved symptoms. In conclusion, CMR should be a mandatory test in patients with suspected MINOCA, because it can not only make a clear diagnosis, but also play an important role in guiding clinical decision-making.

Clinical features and outcomes of patients with stable or unstable chest pain and no-obstructive coronary artery disease

Background

Coronary microvascular dysfunction can be responsible for both stable angina and acute coronary syndrome (ACS). There are scarce data, however, about comparisons of clinical characteristics and outcomes of these 2 groups of patients.

Materials and methods

We studied 47 consecutive patients who underwent coronary angiography for angina syndromes and showed no obstructive stenosis. Patients were divided in 2 groups, according to their clinical presentation, i.e., stable angina (n = 21) or non-ST segment elevation ACS (NSTE-ACS; n = 26). An intracoronary acetylcholine (Ach) test was performed in 12 and 17 patients of the 2 groups, respectively. Angina status, assessed by Seattle Angina Questionnaire (SAQ), and clinical events were assessed after 1, 6, and 30 months. An exercise stress test was performed 1 month after discharge.

Results

Clinical characteristics and exercise test results of the 2 groups were largely similar. Ach testing induced epicardial or microvascular spasm in 6 (50.0%) and 10 (58.8%) stable and NSTE-ACS patients, respectively (p = 0.72). Stable patients reported higher rates of angina, compared to NSTE-ACS patients, both at 1 (p = 0.04) and 30 months (81 vs. 50%, p = 0.036) of follow-up. SAQ scores were also lower in stable vs. NSTE-ACS patients. Ach testing results showed no association with clinical outcomes.

Conclusion

Clinical characteristics and exercise and Ach testing results are similar in angina patients with no-obstructive coronary artery disease with a stable or NSTE-ACS presentation. Stable patients show a worse symptomatic outcome irrespective of Ach test results.

Coronary functional assessment in non-obstructive coronary artery disease: Present situation and future direction

Non-obstructive coronary artery disease (CAD), which is defined as coronary stenosis <50%, has been increasingly recognized as an emerging entity in clinical practice. Vasomotion abnormality and coronary microvascular dysfunction are two major mechanisms contributing to the occur of angina with non-obstructive CAD. Although routine coronary functional assessment is limited due to several disadvantages, functional evaluation can help to understand the pathophysiological mechanism and/or to exclude specific etiologies. In this review, we summarized the potential mechanisms involved in ischemia with non-obstructive coronary arteries (INOCA) and myocardial infarction with non-obstructive coronary arteries (MINOCA), the two major form of non-obstructive CAD. Additionally, we reviewed currently available functional assessment indices and their use in non-obstructive CAD. Furthermore, we speculated that novel technique combined anatomic and physiologic parameters might provide more individualized therapeutic choice for patients with non-obstructive CAD.