Microvascular spasm in non-ST-segment elevation myocardial infarction without culprit lesion (MINOCA)

Non-atherosclerotic coronary causes of myocardial infarction in women

Ischemic heart disease is the most common cardiovascular cause of death in women worldwide. Obstructive coronary atherosclerosis is the primary cause of myocardial infarction (MI), however, non-atherosclerotic mechanisms of MI, such as spontaneous coronary artery dissection, vasospasm, microvascular dysfunction, embolization, inflammation, coronary anomalies, infectious and infiltrative causes are increasingly being recognized. Emerging data suggest that women are two to five times more likely to have an MI in the absence of coronary atherosclerosis compared to men, but they continue to remain underdiagnosed and undertreated, partly due to underdiagnosis and limited understanding of these mechanisms. Recent advancements in invasive and noninvasive imaging techniques and physiological testing allow for distinguishing these mechanisms from each other, providing a definitive diagnosis and tailored treatment. This review summarizes the existing literature on the non-atherosclerotic coronary causes of MI with a focus on evidence pertaining to women, offering a basis for future studies.

Rare Clinical Manifestation of Vasculitis

BACKGROUND

Antineutrophil cytoplasm antibody (ANCA)-associated vasculitis usually affects small blood vessels and is characterized by the presence of circulating autoantibodies (c-ANCA or p-ANCA). The risk of cardiovascular events is threefold higher compared to general population, and cardiac manifestations include myocarditis, pericarditis, valvulitis, aortitis, or coronary arteritis. Coronary involvement is very rare, but it is a potentially life-threatening manifestation.

METHODS

We present an atypical cardiac scenario of p-ANCA vasculitis.

RESULTS

A 68-year-old woman with known p-ANCA vasculitis and stage 5 chronic kidney disease (CKD) on hemodialysis presented with dizziness accompanied by low blood pressure and chest pain. Electrocardiogram on arrival showed slightly ST-T changes, with negative cardiac biomarkers and no abnormalities in cardiac regional wall motion. Five hours after presentation, the patient repeated chest pain, accompanied by a drop in blood pressure and junctional escape rhythm. The highly sensitive cardiac troponin I (hs-cTnI) was raised at 560 ng/L. Coronary angiography showed coronary arteries without significant stenosis. The provocative test with intracoronary ergonovine demonstrated coronary vasospasm of the anterior descending artery accompanied by chest pain, with resolution after intracoronary nitroglycerin. Under amlodipine, nitrate, acetylsalicylic acid, statin and corticosteroids the patient did not experience the recurrence of angina.

CONCLUSIONS

This case illustrates coronary involvement, manifested as coronary spasm with favorable outcomes, in systemic vasculitis. The underlying mechanism is immune-mediated inflammation in vascular walls.

MINOCA: A Pathophysiological Approach of Diagnosis and Treatment-A Narrative Review

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a clinical entity characterized by the absence of significant coronary artery obstruction in epicardial arteries (<50%) on coronary angiography in the setting of acute myocardial infarction (AMI). This article aims to provide a narrative review of the pathophysiological mechanisms, diagnostic challenges, and prognosis associated with MINOCA based on pathophysiology regarding the atherosclerotic and non-atherosclerotic causes. Etiological factors, including thromboembolism, coronary artery spasm, spontaneous coronary artery dissection, coronary microvascular disease, and supply-demand mismatch, are addressed. Imaging modalities such as echocardiography, advances in coronary angiography like intravascular ultrasound (IVUS) and optical coherence tomography (OCT), cardiac magnetic resonance (CMR), and coronary computed tomography angiography (CCTA) are also analyzed. MINOCA patients have a better short-term prognosis compared to those with obstructive coronary artery disease but face significant long-term risks, underscoring the need for precise diagnosis and management strategies. Elevated inflammatory markers and specific genetic predispositions are also associated with adverse outcomes in MINOCA. This review focused on MINOCA from a pathophysiological perspective on the diverse underlying mechanisms, the challenges in achieving accurate diagnosis, the importance of a tailored therapeutic approach and the necessity for further investigation of clinical outcomes.

Comparison of Baseline and Post-Nitrate Exercise Testing in Patients with Angina but Non-Obstructed Coronary Arteries with Different Acetylcholine Test Results

Background: Intracoronary acetylcholine testing may induce epicardial coronary artery spasm (CAS) or coronary microvascular spasm (CMVS) in patients with angina syndromes but non-obstructive coronary artery disease, but their causal role in individual patients is not always clear. In this prospective, observational single-center study, we aimed to assess whether (1) the induction of myocardial ischemia/angina by electrocardiogram (ECG) exercise stress test (EST) differs between patients showing different results in response to acetylcholine testing (i.e., CAS, CMVS, or no spasm); (2) the preventive administration of short-acting nitrates has any different effects on the EST of those patients who showed a positive basal EST. We expected that if exercise-induced angina and/or ischemic ECG changes are related to CAS, they should improve after nitrates administration, whereas they should not significantly improve if they are caused by CMVS. Methods: We enrolled 81 patients with angina syndromes and non-obstructive coronary artery disease, who were divided into three groups according to acetylcholine testing: 40 patients with CAS (CAS-group), 14 with CMVS (CMVS-groups), and 27 with a negative test (NEG-group). All patients underwent a basal EST (B-EST). Patients with a positive B-EST repeated the test 24-48 h later, 5 min after the administration of short-acting nitrates (N-EST). Results: There were no significant differences among the groups in terms of the B-EST results. B-EST was positive in eight (20%) patients in the CAS-group, seven (50%) in the CMVS-group, and six (22%) in the NEG-group (p = 0.076). N-EST, performed in eight, six, and five of these patients, also showed similar results in the three groups. Furthermore, the N-EST results also did not significantly differ compared to B-EST in any group, remaining positive in seven (87.5%), four (66.7%), and four (80%) patients in the CAS-group, CMVS-group, and NEG-group, respectively (p = 0.78). Conclusions: Our data show that patients with angina and non-obstructive coronary artery disease show largely comparable results of the ECG exercise stress test and similar poor effects of short-acting nitrates on abnormal ECG exercise stress test results. On the whole, our findings suggest caution in attributing to the results of Ach testing a definite causal role for the clinical syndrome in individual patients.

Pathophysiology and diagnostic pathway of myocardial infarction with non-obstructive coronary arteries

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a heterogeneous and diverse disease entity, which accounts for about 6 % of all acute myocardial infarction (AMI) cases. In patients with chest pain and acute myocardial injury detected by a highly sensitive troponin assay, the absence of epicardial coronary stenosis of 50 % or greater on angiography leads to the working diagnosis of MINOCA. The updated JCS/CVIT/JCC 2023 Guideline described MINOCA as a new disease concept and recommended a multimodality approach to uncovering the underlying causes of MINOCA. Cardiac magnetic resonance (CMR) is useful in not only making a definite diagnosis of MINOCA, but also excluding non-ischemic causes that mimic AMI such as takotsubo cardiomyopathy and myocarditis. Meanwhile, intracoronary imaging, particularly optical coherence tomography (OCT), enables us to evaluate precisely intracoronary morphological alterations including plaque disruption and spontaneous coronary artery dissection which are not revealed by angiographic findings alone. Recent studies have shown that an initial workup with the combination of CMR and OCT could provide a definite diagnosis in a significant percentage of patients suspected of MINOCA. Consecutively, patients with inconclusive results of a series of CMR and OCT implementation are eligible for assessing the potential for coronary functional abnormalities or blood coagulopathy as another factor involved in the development of MINOCA. Although uncovering the pathogenesis of MINOCA might be essential for establishing an individualized treatment approach, significant knowledge gaps in terms of secondary prevention strategies for MINOCA focusing on the improvement of long-term prognosis remain to be overcome. In this review, we summarize our current understanding of MINOCA and highlight contemporary diagnostic approaches for patients with suspected MINOCA.

CMR reclassifies the majority of patients with suspected MINOCA and non MINOCA

AIMS

In ∼5-15% of all cases of acute coronary syndromes (ACS) have unobstructed coronaries on angiography. Cardiac magnetic resonance (CMR) has proven useful to identify in most patients the underlying diagnosis associated with this presentation. However, the role of CMR to reclassify patients from the initial suspected condition has not been clarified. The aim of this study was to assess the proportion of patients with suspected MINOCA, or non-MINOCA, that CMR reclassifies with an alternative diagnosis from the original clinical suspicion.

METHODS AND RESULTS

A retrospective cohort of patients in a tertiary cardiology centre was identified from a registry database. Patients who were referred for CMR for investigation of suspected MINOCA, and a diagnosis pre- and post-CMR was recorded to determine the proportion of diagnoses reclassified. A total of 888 patients were identified in the registry. CMR reclassified diagnosis in 78% of patients. Diagnosis of MINOCA was confirmed in only 243 patients (27%), whilst most patients had an alternative diagnosis (73%): myocarditis n = 217 (24%), Takotsubo syndrome n = 115 (13%), cardiomyopathies n = 97 (11%), and normal CMR/non-specific n = 216 (24%).

CONCLUSION

In a large single-centre cohort of patients presenting with ACS and unobstructed coronary arteries, most patients had a non-MINOCA diagnosis (73%) (myocarditis, Takotsubo, cardiomyopathies, or normal CMR/non-specific findings), whilst only a minority had confirmed MINOCA (27%). Performing CMR led to reclassifying patients' diagnosis in 78% of cases, thus confirming its important clinical role and underscoring the clinical challenge in diagnosing MINOCA and non MINOCA conditions.

Reduced stress perfusion in myocardial infarction with nonobstructive coronary arteries

Myocardial infarction with nonobstructive coronary arteries (MINOCA) has several possible underlying causes, including coronary microvascular dysfunction (CMD). Early cardiovascular magnetic resonance imaging (CMR) is recommended, however cannot provide a diagnosis in 25% of cases. Quantitative stress CMR perfusion mapping can identify CMD, however it is unknown if CMD is present during long-term follow-up of MINOCA patients. Therefore, this study aimed to evaluate presence of CMD during long-term follow-up in MINOCA patients with an initial normal CMR scan. MINOCA patients from the second Stockholm myocardial infarction with normal coronaries study (SMINC-2), with a normal CMR scan at median 3 days after hospitalization were investigated with comprehensive CMR including stress perfusion mapping a median of 5 years after the index event, together with age- and sex-matched volunteers without symptomatic ischemic heart disease. Cardiovascular risk factors, medication and symptoms of myocardial ischemia measured by the Seattle Angina Questionnaire 7 (SAQ-7), were registered. In total, 15 patients with MINOCA and an initial normal CMR scan (59 ± 7 years old, 60% female), and 15 age- and sex-matched volunteers, underwent CMR. Patients with MINOCA and an initial normal CMR scan had lower global stress perfusion compared to volunteers (2.83 ± 1.8 vs 3.53 ± 0.7 ml/min/g, p = 0.02). There were no differences in other CMR parameters, hemodynamic parameters, or cardiovascular risk factors, except for more frequent use of statins in the MINOCA patient group compared to volunteers. In conclusion, global stress perfusion is lower in MINOCA patients during follow-up, compared to age- and sex-matched volunteers, suggesting that CMD may be a possible pathophysiological mechanism in MINOCA.Clinical Trial Registration: Clinicaltrials.gov identifier NCT02318498. Registered 2014-12-17.

Chinese expert consensus on the diagnosis and treatment of coronary microvascular diseases (2023 Edition)

Since the four working groups of the Chinese Society of Cardiology issued first expert consensus on coronary microvascular diseases (CMVD) in 2017, international consensus documents on CMVD have increased rapidly. Although some of these documents made preliminary recommendations for the diagnosis and treatment of CMVD, they did not provide classification of recommendations and levels of evidence. In order to summarize recent progress in the field of CMVD, standardize the methods and procedures of diagnosis and treatment, and identify the scientific questions for future research, the four working groups of the Chinese Society of Cardiology updated the 2017 version of the Chinese expert consensus on CMVD and adopted a series of measures to ensure the quality of this document. The current consensus has raised a new classification of CMVD, summarized new epidemiological findings for different types of CMVD, analyzed key pathological and molecular mechanisms, evaluated classical and novel diagnostic technologies, recommended diagnostic pathways and criteria, and therapeutic strategies and medications, for patients with CMVD. In view of the current progress and knowledge gaps of CMVD, future directions were proposed. It is hoped that this expert consensus will further expedite the research progress of CMVD in both basic and clinical scenarios.

Coronary microvascular dysfunction and myocardial infarction with non-obstructive coronary arteries: Where do we stand?

In the past decade, scientific and clinical research has provided a translational perspective on myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA). MINOCA is characterized by clinical documentation of an acute MI but angiography shows no significant coronary artery obstruction (stenosis <50%). The prevalence of MINOCA is estimated to range from approximately 6 to 10% among MI patients, and those with this condition have a poor prognosis, experiencing high rates of mortality, rehospitalization, and socioeconomic burden. MINOCA represents a major unmet need in cardiovascular medicine, with uncertain clinical management. It is a complex condition that can be caused by various factors, including atherosclerosis, plaque rupture, coronary vasospasm, and microvascular dysfunction. Effective management of MINOCA depends on identifying the underlying mechanism of the infarction, thus a systematic diagnostic approach is recommended. Contemporary data shows that a significant number of patients exhibit structural and functional abnormalities in coronary microcirculation, which is referred to as coronary microvascular dysfunction (CMD). CMD plays a crucial role in patients with signs and symptoms of myocardial ischemia and non-obstructive coronary artery stenosis, including MINOCA. Furthermore, conducting a thorough evaluation of coronary function can have significant prognostic and therapeutic implications, since personalized patient management strategies based on this assessment have been shown to improve symptoms and prognosis. Therefore, an accurate and timely diagnosis of CMD is essential for effective patient management, which can be achieved through various invasive and non-invasive methods. This review will discuss the pathophysiological understanding, current diagnostic techniques, and management strategies of patients with MINOCA and CMD.

Coronary microvascular dysfunction and cardiovascular disease: Pathogenesis, associations and treatment strategies

Coronary microvascular dysfunction (CMD) is a high-risk factor for a variety of cardiovascular events. Due to its complex aetiology and concealability, knowledge of the pathophysiological mechanism of CMD is still limited at present, which greatly restricts its clinical diagnosis and treatment. Studies have shown that CMD is closely related to a variety of cardiovascular diseases, can aggravate the occurrence and development of cardiovascular diseases, and is closely related to a poor prognosis in patients with cardiovascular diseases. Improving coronary microvascular remodelling and increasing myocardial perfusion might be promising strategies for the treatment of cardiovascular diseases. In this paper, the pathogenesis and functional assessment of CMD are reviewed first, along with the relationship of CMD with cardiovascular diseases. Then, the latest strategies for the treatment of CMD and cardiovascular diseases are summarized. Finally, urgent scientific problems in CMD and cardiovascular diseases are highlighted and future research directions are proposed to provide prospective insights for the prevention and treatment of CMD and cardiovascular diseases in the future.

Invasive Evaluation for Coronary Vasospasm

Vasospastic angina (VSA) occurs at rest and on exertion, with transient electrocardiographic ischemic changes. VSA presents with spontaneous coronary artery spasm (CAS); it has been associated with stable angina, acute coronary syndromes, and sudden cardiac death. CAS can be identified in normal arteries or non-obstructive coronary atherosclerosis, but is also prevalent in patients with coronary artery disease. The diagnosis is made with invasive coronary reactivity testing with provocation using acetylcholine (Ach). Epicardial spasms can be visualized through coronary angiography as a reversible epicardial vessel narrowing, while the diagnosis of microvascular spasm can be made when angina symptoms and ECG changes happen following intracoronary Ach without epicardial spasm. Identification of CAS allows for risk stratification and specific therapies targeting endothelial dysfunction and paradoxical vascular smooth muscle cell constriction. Therapies include calcium channel blockers as monotherapy or in a combination of a dihydropyridine and non-dihydropyridine. Short-acting nitrates offer acute symptomatic relief but long-acting nitrates should be used sparingly. This current update on invasive evaluation of VSA discusses unified Ach protocols.

Frequency and Clinical Impact of Family History of Coronary Artery Disease in Patients with Vasospastic Angina

BACKGROUND

Family history (FH) of coronary artery disease (CAD) [FH-CAD] is a well-known risk factor for atherosclerotic CAD. However, FH-CAD frequency in patients with vasospastic angina (VSA) remains unknown, and the clinical characteristics and prognosis of VSA patients with FH-CAD are unclear. Therefore, this study compared FH-CAD frequency between patients with atherosclerotic CAD and those with VSA and examined the clinical characteristics and prognosis of VSA patients with FH-CAD.

METHODS

Coronary angiography and spasm provocation tests (SPT) were used to investigate chest pain of coronary artery origin in patients classified into atherosclerotic CAD (362 cases), VSA (221 cases; positive for SPT) and non-VSA (73 cases; negative for SPT) groups, with FH-CAD being defined. In the VSA group, flow-mediated vasodilation (FMD) and nitroglycerin-independent vasodilation (NID) via brachial artery echocardiography and clinical symptoms in the groups with and without FH-CAD were checked, with Kaplan-Meier curves revealing major adverse cardiovascular events (cardiac death and rehospitalisation for cardiovascular disease) between the two groups.

RESULTS

The atherosclerotic CAD group had a significantly lower FH-CAD frequency (12%, p = 0.029) than the VSA (19%) and non-VSA groups (19%). FH-CAD was more common in females in the VSA and non-VSA groups than in the atherosclerotic CAD group (p < 0.001). Nonpharmacological treatment for CAD in FH-CAD was more common in the atherosclerotic CAD group (p = 0.017). In the VSA group, FH-CAD tended to be more common in females (p = 0.052). Although no differences in FMD of the brachial artery were observed between the groups, the FH-CAD (+) group had significantly higher NID than the FH-CAD (-) group (p = 0.023). Kaplan-Meier's analysis revealed a similar prognosis between the two groups, and other clinical characteristics did not differ.

CONCLUSION

Patients with VSA have a higher FH-CAD frequency than those with atherosclerotic CAD, especially in females. Although FH-CAD may affect vascular function in patients with VSA, its effect on the severity and prognosis of VSA appears to be minimal. FH-CAD and its confirmation may assist in CAD diagnosis, especially in female patients.

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.

Coronary Microvascular Spasm: Clinical Presentation and Diagnosis

Professor Maseri pioneered the research and treatment of coronary vasomotion abnormalities represented by coronary vasospasm and coronary microvascular dysfunction (CMD). These mechanisms can cause myocardial ischaemia even in the absence of obstructive coronary artery disease, and have been appreciated as an important aetiology and therapeutic target with major clinical implications in patients with ischaemia with non-obstructive coronary artery disease (INOCA). Coronary microvascular spasm is one of the key mechanisms responsible for myocardial ischaemia in patients with INOCA. Comprehensive assessment of coronary vasomotor reactivity by invasive functional coronary angiography or interventional diagnostic procedure is recommended to identify the underlying mechanisms of myocardial ischaemia and to tailor the best treatment and management based on the endotype of INOCA. This review highlights the pioneering works of Professor Maseri and contemporary research on coronary vasospasm and CMD with reference to endothelial dysfunction, Rho-kinase activation and inflammation.

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.

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.

Ischemic Heart Disease in Young Women: JACC Review Topic of the Week

The Cardiovascular Disease in Women Committee of the American College of Cardiology convened a working group to develop a consensus regarding the continuing rise of mortality rates in young women aged 35 to 54 years. Heart disease mortality rates in young women continue to increase. Young women have increased mortality secondary to ischemic heart disease (IHD) compared with comparably aged men and similar mortality to that observed among older women. The authors reviewed the published evidence, including observational and mechanistic/translational data, and identified knowledge gaps pertaining to young women. This paper provides clinicians with pragmatic, evidence-based management strategies for young women at risk for IHD. Next-step research opportunities are outlined. This report presents highlights of the working group review and a summary of suggested research directions to advance the IHD field in the next decade.

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.

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.

Pathophysiology and mechanisms of Acute Coronary Syndromes: atherothrombosis, immune-inflammation, and beyond

INTRODUCTION

The pathophysiology of atherosclerosis and its acute complications, such as the Acute Coronary Syndromes (ACS), is continuously under investigation. Immunity and inflammation seem to play a pivotal role in promoting formation and grow of atherosclerotic plaques. At the same time, plaque rupture followed by both platelets' activation and coagulation cascade induction lead to intracoronary thrombus formation. Although these phenomena might be considered responsible of about 90% of ACS, in up to 5-10% of acute syndromes, a non-obstructive coronary artery disease (MINOCA) might be documented. This paper gives an overview on atherothrombosis and immuno-inflammation processes involved in ACS pathophysiology, also emphasizing the pathological mechanisms potentially involved in MINOCA.

AREAS COVERED

The relationship between immuno-inflammation and atherothrombosis is continuously updated by recent findings. At the same time, pathophysiology of MINOCA still remains a partially unexplored field, stimulating the research of potential links between these two aspects of ACS pathophysiology.

EXPERT OPINION

Pathophysiology of ACS has been extensively investigated; however, several gray areas still remain. MINOCA represents one of these areas. At the same time, many aspects of immune-inflammation processes are still unknown. Thus, research should be continued to shed a brighter light on both these sides of "ACS" moon.

Prevalence of Coronary Microvascular Disease and Coronary Vasospasm in Patients With Nonobstructive Coronary Artery Disease: Systematic Review and Meta-Analysis

Background

A relevant proportion of patients with suspected coronary artery disease undergo invasive coronary angiography showing normal or nonobstructive coronary arteries. However, the prevalence of coronary microvascular disease (CMD) and coronary spasm in patients with nonobstructive coronary artery disease remains to be determined. The objective of this study was to determine the prevalence of coronary CMD and coronary vasospastic angina in patients with no obstructive coronary artery disease.

Methods and Results

A systematic review and meta‐analysis of studies assessing the prevalence of CMD and vasospastic angina in patients with no obstructive coronary artery disease was performed. Random‐effects models were used to determine the prevalence of these 2 disease entities. Fifty‐six studies comprising 14 427 patients were included. The pooled prevalence of CMD was 0.41 (95% CI, 0.36–0.47), epicardial vasospasm 0.40 (95% CI, 0.34–0.46) and microvascular spasm 24% (95% CI, 0.21–0.28). The prevalence of combined CMD and vasospastic angina was 0.23 (95% CI, 0.17–0.31). Female patients had a higher risk of presenting with CMD compared with male patients (risk ratio, 1.45 [95% CI, 1.11–1.90]). CMD prevalence was similar when assessed using noninvasive or invasive diagnostic methods.

Conclusions

In patients with no obstructive coronary artery disease, approximately half of the cases were reported to have CMD and/or coronary spasm. CMD was more prevalent among female patients. Greater awareness among physicians of ischemia with no obstructive coronary arteries is urgently needed for accurate diagnosis and patient‐tailored management.

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.

The Role of Cardiac Magnetic Resonance in Myocardial Infarction and Non-obstructive Coronary Arteries

Myocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA) accounts for 5–15% of all presentations of acute myocardial infarction. The absence of obstructive coronary disease may present a diagnostic dilemma and identifying the underlying etiology ensures appropriate management improving clinical outcomes. Cardiac magnetic resonance (CMR) imaging is a valuable, non-invasive diagnostic tool that can aide clinicians to build a differential diagnosis in patients with MINOCA, as well as identifying non-ischemic etiologies of myocardial injury (acute myocarditis, Takotsubo Syndrome, and other conditions). The role of CMR in suspected MINOCA is increasingly recognized as emphasized in both European and American clinical guidelines. In this paper we review the indications for CMR, the clinical value in the differential diagnosis of patients with suspected MINOCA, as well as its current limitations and future perspectives.

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.

The Pivotal Role of Invasive Functional Assessment in Patients With Myocardial Infarction With Non-Obstructive Coronary Arteries (MINOCA)

Myocardial infarction with non-obstructive coronary arteries (MINOCA) encompasses several pathophysiological mechanisms not yet fully understood. Among the latter, vasomotion abnormalities and coronary microvascular dysfunction (CMD) play a major role for both epidemiological and prognostic reasons. Despite current guidelines do not recommend routine physiological assessment of both epicardial and microvascular coronary compartments within the context of an acute myocardial infarction, several recent evidence support the critical role of a comprehensive invasive functional assessment in order to identify the underlying pathophysiological mechanism and consequently to select an appropriate therapeutic strategy. Unfortunately, optimal medical therapy for these patients is not currently established due to the lack of dedicated trials evaluating clinical outcomes of commonly used medications for secondary prevention in MINOCA patients. For this reason, additional research is warranted to provide personalized treatments for patients affected by this puzzling clinical entity.

Prognostic impact of coronary microvascular dysfunction in patients with myocardial infarction with non-obstructive coronary arteries

BACKGROUND

Myocardial infarction with non-obstructive coronary arteries (MINOCA) has been and remained a puzzling heterogeneous entity. The index of microcirculatory resistance (IMR) is a quantitative and specific index for the assessment of microvascular function. However, the role of IMR in MINOCA has not yet been studied. This study aimed to evaluate the prognostic value of coronary microvascular function, as assessed by coronary angiography‑derived index of microvascular resistance (caIMR) in MINOCA patients.

METHOD

This study included 109 MINOCA patients. Microvascular function was assessed by caIMR and was analyzed in 280 coronary arteries. The primary endpoint of the study was MACE, defined as cardiovascular death, nonfatal MI, heart failure, stroke and angina rehospitalization. The best cut-off of caIMR was derived from ROC analysis based on MACE prediction.

RESULTS

The patients were classified into high caIMR (caIMR>43U) and low caIMR (caIMR≤43U) based on a caIMR cut-off value of 43U. High caIMR was observed in 55 (50.5%) patients. A total of 27 MACE occurred during the 2 years of follow-up. MACE rate was significantly higher in patients with high caIMR than in patients with low caIMR (36.4% vs 13.0%, P=0.005). The Kaplan-Meier curves showed a significantly increased risk of MACE in patients with high caIMR (log-rank P=0.001). Cox multivariate analysis showed that caIMR>43 was a highly independent predictor of MACE (HR, 3.08; 95% CI, 1.13 - 8.35; P=0.027).

CONCLUSIONS

caIMR is a strong predictor of clinical outcome among MINOCA patients. The evaluation of IMR can provide an objective risk stratification method for patients with MINOCA.

Diagnostic approach for coronary microvascular dysfunction in patients with chest pain and no obstructive coronary artery disease

A large number of studies has demonstrated that abnormalities of coronary microcirculation may be responsible for both acute and chronic cardiac ischemic syndromes. In clinical practice the microvascular origin of myocardial ischemia and angina is usually considered in patients who are found to have normal or near-normal coronary arteries at angiography. In this article, we review the diagnostic approach to patients with suspected coronary microvascular dysfunction as a cause of ischemic syndromes and also suggest a classification of chronic and acute microvascular coronary ischemic syndrome, including myocardial infarction with normal coronary arteries.

Prognostic value of statin therapy in patients with myocardial infarction with nonobstructive coronary arteries (MINOCA): a meta-analysis

BACKGROUND

Given the complex aetiology and a limited amount of evidence, the medical treatment (including statin use) of myocardial infarction with non-obstructive coronary artery disease (MINOCA) remains uncertain. The objective of the present study was to evaluate the effect of statin therapy on major cardiovascular events (MACE) and mortality in MINOCA patients.

METHODS

A systematic review and meta-analysis of time-to-event outcomes were performed of studies of statin therapy on MINOCA patients, reporting data from MACE or mortality, after searching the PubMed/MEDLINE, Embase, Science Direct, Scopus, Google Scholar, and Cochrane databases. A fixed-effects meta-analysis model was then applied.

RESULTS

Six observational studies of statin therapy on MINOCA, involving a total of 11,171 patients, were identified and considered eligible for analysis (9129 subjects received statin therapy while 2042 patients were part of the respective control arms). Quantitative analysis (5 studies were included) showed that statin use was associated with lower mortality (HR: 0.65; 95% CI: 0.56-0.75, I²: 0%). Also, the meta-analysis showed that statin therapy was associated with a lower incidence of MACE (HR: 0.78; 95% CI: 0.69-0.88, I²:27%).

CONCLUSION

Our data suggest that in a population with MINOCA, the use of statin therapy results in significant reduction on MACE and mortality. These results must be confirmed in future clinical trials.

The role of a comprehensive two-step diagnostic evaluation to unravel the pathophysiology of MINOCA: A review

The role of cardiac magnetic resonance (CMR) in identifying mechanisms for myocardial infarction with non-obstructed coronary arteries (MINOCA) is well established. Recent reports have highlighted the potentially key role of invasive management in this diagnostic process. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) allow precise evaluation of coronary anatomy, and assessment of coronary physiology in the catheter laboratory provides information on the hemodynamic significance of sub-critical atherosclerosis and on coronary microvascular dysfunction (CMD). We reviewed the evidence for the contribution of invasive diagnostic techniques in identifying provisional causes for MINOCA. Overall, among 82 studies including 8457 patients were selected. In the acute phase, 16 studies with IVUS or OCT (1207 patients) disclosed that plaque disruption and spontaneous coronary artery dissection had a pooled prevalence of 38% (95% confidence intervals (CI): 29% to 51%) and 16% (95% CI: 9% to 27%), respectively. In 18 studies, coronary function testing (1449 patients) showed a pooled prevalence of spontaneous and/or provoked epicardial coronary spasm of ~28% (95% CI:17% to 41%). In 3 studies (456 patients), the pooled prevalence of CMD was ~32% (95% CI: 20% to 49%). In the subacute phase, 42 CMR studies (5821 patients) showed that a pooled prevalence of myocarditis, takotsubo syndrome and cardiomyopathy of 26% (95% CI: 12% to 40%), 11% (95% CI: 5% to 25%), and 7% (95% CI: 1% to 19%), respectively. In 12 studies on thrombophilia screening (n = 834), the pooled prevalence of thrombotic disorder was ~11% (95% CI: 7%% to 25%). In conclusion, the pathophysiology of MINOCA can be established in the majority of cases using both invasive and non-invasive tools to provide direction for appropriate management.

Safety assessment and results of coronary spasm provocation testing in patients with myocardial infarction with unobstructed coronary arteries compared to patients with stable angina and unobstructed coronary arteries

BACKGROUND

Coronary spasm is an established cause for myocardial infarction with unobstructed coronary arteries, and can be diagnosed using intracoronary acetylcholine testing. However, it has been questioned whether such testing is feasible and safe in the acute phase. The aim of this study was to assess the frequency of coronary spasm and the safety of the acetylcholine test in patients with myocardial infarction with unobstructed coronary arteries compared to patients with stable angina and unobstructed coronaries.

METHODS

One hundred and eighty selected patients (52% women, mean age 62±13 years) with either myocardial infarction with unobstructed coronary arteries (n=80) or stable angina and unobstructed coronaries (n=100) were enrolled from 2007-2018. All patients underwent the acetylcholine test according to a standardised protocol immediately after diagnostic angiography. Apart from assessment of clinical, demographic and risk factor data, side effects and complications during the acetylcholine test were recorded.

RESULTS

Overall, epicardial spasm was found in 26% with a higher prevalence among the myocardial infarction with unobstructed coronary arteries compared to the stable angina patients (35% vs 19%, p=0.017). Microvascular spasm was found in 42% with a higher prevalence among the stable patients compared to the myocardial infarction with unobstructed coronary arteries cohort (53% vs 29%, p=0.0014). There were no statistically significant differences in the rate of side effects (16% vs 14%, p=0.674) or complications (1% vs 2.5%, p=0.438) between the two groups. None of the patients experienced irreversible complications.

CONCLUSION

Coronary spasm is a frequent cause for myocardial infarction with unobstructed coronary arteries. Spasm provocation testing using acetylcholine is feasible in such patients in the acute phase. The complication rate during acetylcholine testing in myocardial infarction with unobstructed coronary arteries patients is low and comparable to patients with stable angina.

Myocardial infarction with nonobstructive coronary artery disease (MINOCA): a review of pathophysiology and management

PURPOSE OF REVIEW

Myocardial infarction with nonobstructive coronary artery disease (MINOCA) (≥ 50% stenosis) accounts for 5-8% of acute coronary syndrome (ACS) presentations. The demographic characteristics, risk factors, and management of patients with MINOCA differ from those with atherosclerotic ACS. The objective of this review is to provide a contemporary understanding of the epidemiology, pathophysiology, clinical presentation, and management of MINOCA.

RECENT FINDINGS

MINOCA is increasingly being recognized as an important and distinct cause of myocardial infarction among patients presenting with ACS. The predominant pathophysiologic mechanisms of MINOCA include both coronary (epicardial vasospasm, coronary microvascular disorder, spontaneous coronary artery dissection, coronary thrombus/embolism) and noncoronary (Takotsubo cardiomyopathy, myocarditis) pathologies. Coronary imaging with intravascular ultrasound and optical coherent tomography, coronary physiology testing, and cardiac magnetic resonance imaging offers important investigative modalities to facilitate diagnosis for appropriate management of MINOCA patients.

SUMMARY

MINOCA is an important cause of ACS observed in certain patients with unique challenges for diagnosis and management. A high index of suspicion and a comprehensive diagnostic evaluation are critical for early recognition and successful management.

Early Comprehensive Cardiovascular Magnetic Resonance Imaging in Patients With Myocardial Infarction With Nonobstructive Coronary Arteries

OBJECTIVES

The objective of the SMINC-2 (Stockholm Myocardial Infarction With Normal Coronaries 2) study was to determine if more than 70% of patients with myocardial infarction with nonobstructed coronary arteries (MINOCA), investigated early with comprehensive cardiovascular magnetic resonance (CMR), could receive a diagnosis entirely by imaging.

BACKGROUND

The etiology of MINOCA is heterogeneous, including coronary, cardiac, and noncardiac causes. Patients with MINOCA, therefore, represent a diagnostic challenge where CMR is increasingly used.

METHODS

The SMINC-2 study was a prospective study of 148 patients with MINOCA imaged with 1.5-T CMR with T₁ and extracellular volume mapping early after hospital admission, compared to 150 patients with MINOCA imaged using 1.5-T CMR without mapping techniques from the SMINC-1 study as historic controls.

RESULTS

CMR was performed at a median of 3 (SMINC-2) versus 12 (SMINC-1) days after hospital admission. In total, 77% of patients received a diagnosis with CMR imaging in the SMINC-2 study compared to 47% in the SMINC-1 study (p < 0.001). Compared to SMINC-1, CMR in SMINC-2 detected higher proportions of myocarditis (17% vs. 7%; p = 0.01) and takotsubo syndrome (35% vs. 19%; p = 0.002) but similar proportions of myocardial infarction (22% vs. 19%; p = 0.56) and other cardiomyopathies (3% vs. 2%; p = 0.46).

CONCLUSIONS

The results of the SMINC-2 study show that 77% of all patients with MINOCA received a diagnosis when imaged early with CMR, including advanced tissue characterization, which was a considerable improvement in comparison to the SMINC-1 study. This supports the use of early CMR imaging as a diagnostic tool in the investigation of patients with MINOCA. (Stockholm Myocardial Infarction With Normal Coronaries [SMINC]-2 Study on Diagnosis Made by Cardiac MRI [SCMINC-2]; NCT02318498).

Coronary Optical Coherence Tomography and Cardiac Magnetic Resonance Imaging to Determine Underlying Causes of Myocardial Infarction With Nonobstructive Coronary Arteries in Women

BACKGROUND

Myocardial infarction with nonobstructive coronary arteries (MINOCA) occurs in 6% to 15% of myocardial infarctions (MIs) and disproportionately affects women. Scientific statements recommend multimodality imaging in MINOCA to define the underlying cause. We performed coronary optical coherence tomography (OCT) and cardiac magnetic resonance (CMR) imaging to assess mechanisms of MINOCA.

METHODS

In this prospective, multicenter, international, observational study, we enrolled women with a clinical diagnosis of myocardial infarction. If invasive coronary angiography revealed <50% stenosis in all major arteries, multivessel OCT was performed, followed by CMR (cine imaging, late gadolinium enhancement, and T2-weighted imaging and T1 mapping). Angiography, OCT, and CMR were evaluated at blinded, independent core laboratories. Culprit lesions identified by OCT were classified as definite or possible. The CMR core laboratory identified ischemia-related and nonischemic myocardial injury. Imaging results were combined to determine the mechanism of MINOCA, when possible.

RESULTS

Among 301 women enrolled at 16 sites, 170 were diagnosed with MINOCA, of whom 145 had adequate OCT image quality for analysis; 116 of these underwent CMR. A definite or possible culprit lesion was identified by OCT in 46.2% (67/145) of participants, most commonly plaque rupture, intraplaque cavity, or layered plaque. CMR was abnormal in 74.1% (86/116) of participants. An ischemic pattern of CMR abnormalities (infarction or myocardial edema in a coronary territory) was present in 53.4% (62/116) of participants undergoing CMR. A nonischemic pattern of CMR abnormalities (myocarditis, takotsubo syndrome, or nonischemic cardiomyopathy) was present in 20.7% (24/116). A cause of MINOCA was identified in 84.5% (98/116) of the women with multimodality imaging, higher than with OCT alone (P<0.001) or CMR alone (P=0.001). An ischemic cause was identified in 63.8% of women with MINOCA (74/116), a nonischemic cause was identified in 20.7% (24/116) of the women, and no mechanism was identified in 15.5% (18/116).

CONCLUSIONS

Multimodality imaging with coronary OCT and CMR identified potential mechanisms in 84.5% of women with a diagnosis of MINOCA, 75.5% of which were ischemic and 24.5% of which were nonischemic, alternate diagnoses to myocardial infarction. Identification of the cause of MINOCA is feasible and has the potential to guide medical therapy for secondary prevention. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02905357.

Definitions and Epidemiology of Coronary Functional Abnormalities

Coronary functional abnormalities are frequent causes of angina pectoris, particularly in patients with unobstructed coronary arteries. There is a spectrum of endotypes of functional coronary abnormalities with different mechanisms of pathology including enhanced vasoconstriction (i.e. coronary artery spasm) or impaired vasodilatation, such as impaired coronary flow reserve or increased microvascular resistance. These vasomotor abnormalities can affect various compartments of the coronary circulation such as the epicardial conduit arteries and/or the coronary microcirculation. Unequivocal categorisation and nomenclature of the broad spectrum of disease endotypes is crucial both in clinical practice as well as in clinical trials. This article describes the definitions of coronary functional abnormalities with currently accepted cut-off values, as well as diagnostic methods to identify and distinguish endotypes. The authors also provide a summary of contemporary data on the prevalence of the different endotypes of coronary functional abnormalities and their coexistence.

Clinical and electrocardiographic features of patients with myocardial infarction with non-obstructive coronary artery disease (MINOCA)

AIMS

Myocardial infarction with non-obstructive coronary artery disease (MINOCA) is often an underdiagnosed and undertreated condition. This study aimed to evaluate clinical and ECG characteristics of MINOCA in a large cohort of patients admitted for acute coronary syndrome.

METHODS

All coronary angiograms performed at the University Heart Center in Zurich (Switzerland) between 2012 and 2016 were investigated. MINOCA was defined according to European Society of Cardiology guidelines and patients were divided into two groups, based on the presence or absence of coronary sclerosis at angiogram[nonobstructive coronary artery disease (noCAD) and normal coronary arteries (NCA)]), after exclusion of myocarditis and Takotsubo syndrome.

RESULTS

Out of 13 669 angiographic studies, 3695 were diagnosed with acute coronary syndrome; of these, 244 patients presented MINOCA (6.6%). Patients with noCAD were more likely to be older (67.9 vs. 59.2 years, P < 0.001) with higher prevalence of traditional cardiovascular risk factors (hypertension 64.1 vs. 41.2%, P = 0.002; diabetes 19.7 vs. 10.8%, P = 0.036; hypercholesterolemia 36.6 vs. 23.5%, P = 0.037). On surface ECG, anterior ST- segment elevation was more frequent in NCA patients (13.7 vs. 5.0%, P = 0.016). Secondary prevention therapy was significantly more prescribed in noCAD compared with NCA patients (acetylsalicylic acid 68.3 vs. 21.6%, P less than 0.001; statins 76.1 vs. 22.5%, P less than 0.001; angiotensin-converting enzyme inhibitor-AT1 blockers 51.4 vs. 31.3%, P = 0.006). One-year mortality was very low (0.4% for noCAD patients).

CONCLUSION

noCAD patients were older, with higher prevalence of cardiovascular risk factors and more frequently discharged with secondary prevention therapy. NCA patients presented more frequently anterior ST- segment elevation. Further diagnostic tests should be highly recommended to determine the underlying mechanism of MINOCA.

Mechanisms of myocardial infarction with nonobstructive coronary atherosclerosis: a multifaceted play of different actors with guarded prognosis

PURPOSE OF REVIEW

Myocardial infarction (MI) with nonobstructive coronary atherosclerosis (MINOCA) on invasive angiography (stenosis severity <50%) is a heterogenous clinical entity with a prevalence between 6 and 8% of all MI. Whereas the long-term prognosis of MINOCA is not benign, the identification of its underlying mechanism is critical for appropriate risk stratification and tailored secondary prevention strategies.

RECENT FINDINGS

The current review summarizes the contemporary data on the mechanisms, diagnosis, management strategies and outcomes of MINOCA.

SUMMARY

MINOCA is a relatively common form of MI with guarded prognosis. The use of additional diagnostic tests (particularly intracoronary imaging and cardiac magnetic resonance) is paramount to determine the exact cause of MINOCA and implement tailored medical interventions.