Effects of angiotensin-converting enzyme inhibitors and beta blockers on clinical outcomes in patients with and without coronary artery obstructions at angiography (from a Register-Based Cohort Study on Acute Coronary Syndromes)

Canadian Cardiovascular Society/Canadian Women's Heart Health Alliance Clinical Practice Update on Myocardial Infarction With No Obstructive Coronary Artery Disease (MINOCA)

Myocardial infarction with no obstructive coronary artery disease (MINOCA) represents 6%-15% of all acute coronary syndromes, and women are disproportionately represented. MINOCA is an encompassing preliminary diagnosis, and emerging evidence supports a more expansive comprehensive diagnostic and therapeutic clinical approach. The current clinical practice update summarizes the latest evidence regarding the epidemiology, clinical presentation, and diagnostic evaluation of MINOCA. A cascaded approach to diagnostic workup is outlined for clinicians, for noninvasive and invasive diagnostic pathways, depending on clinical setting and local availability of diagnostic modalities. Evidence concerning the nonpharmacological and pharmacological treatment of MINOCA are presented and summarized according to underlying cause of MINOCA, with practical tips on the basis of expert opinion, outlining a real-life, evidence-based, comprehensive approach to management of this challenging condition.

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.

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.

Mortality in ST-Segment Elevation Myocardial Infarction With Nonobstructive Coronary Arteries and Mimickers

Importance

The clinical characteristics and prognosis of patients with ST-segment elevation myocardial infarction (STEMI) with nonobstructive coronaries (MINOCA) are largely unknown.

Objective

To assess differences in 5-year mortality in patients presenting with STEMI due to MINOCA and MINOCA mimickers as compared with obstructive disease.

Design, Setting, and Participants

A retrospective analysis of a prospective registry-based cohort study of consecutive STEMI activations at 3 regional Midwest STEMI programs. STEMI without a culprit artery and elevated troponin levels were categorized as MINOCA (absence of coronary artery stenosis >50% and confirmed or suspected coronary artery plaque disruption, epicardial coronary spasm, or coronary embolism/thrombosis) or MINOCA mimickers (takotsubo cardiomyopathy, myocarditis, or nonischemic cardiomyopathy). Data were analyzed from March 2003 to December 2020.

Main Outcomes and Measures

Adjusted Cox regression analysis was used to assess 5-year mortality risk in STEMI presenting with MINOCA and MINOCA mimickers in comparison with obstructive disease.

Results

Among 8560 consecutive patients with STEMI, mean (SD) age was 62 (14) years, 30% were female (2609 participants), and 94% were non-Hispanic White (4358 participants). The cohort included 8151 patients with STEMI due to obstructive disease (95.2%), 120 patients with MINOCA (1.4%), and 289 patients with MINOCA mimickers (3.8%). Patients were followed up for a median (IQR) of 7.1 (3.6-10.7) years. Patients with MINOCA and MINOCA mimickers were less likely to be discharged with cardiac medications compared with obstructive disease. At 5-year follow-up, mortality in STEMI presenting with obstructive disease (1228 participants [16%]) was similar to MINOCA (20 participants [18%]; χ21 = 1.1; log-rank P = .29) and MINOCA mimickers (52 participants [18%]; χ21 = 2.3; log-rank P = .13). In adjusted Cox regression analysis compared with obstructive disease, the 5-year mortality hazard risk was 1.93 times higher in MINOCA (95% CI, 1.06-3.53) and similar in MINOCA mimickers (HR, 1.08; 95% CI, 0.79-1.49).

Conclusions and Relevance

In this large multicenter cohort study of consecutive clinical patients with STEMI, presenting with MINOCA was associated with a higher risk of mortality than obstructive disease; the risk of mortality was similar in patients with MINOCA mimickers and obstructive disease. Further investigation is necessary to understand the pathophysiologic mechanisms involved in this high-risk STEMI population.

Diagnostic Puzzles and Cause-Targeted Treatment Strategies in Myocardial Infarction with Non-Obstructive Coronary Arteries: An Updated Review

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is a distinct subtype of myocardial infarction (MI), occurring in about 8-10% of spontaneous MI cases referred for coronary angiography. Unlike MI with obstructive coronary artery disease, MINOCA's pathogenesis is more intricate and heterogeneous, involving mechanisms such as coronary thromboembolism, coronary vasospasm, microvascular dysfunction, dissection, or plaque rupture. Diagnosing MINOCA presents challenges and includes invasive and non-invasive strategies aiming to differentiate it from alternative diagnoses and confirm the criteria of elevated cardiac biomarkers, non-obstructive coronary arteries, and the absence of alternate explanations for the acute presentation. Tailored management strategies for MINOCA hinge on identifying the underlying cause of the infarction, necessitating systematic diagnostic approaches. Furthermore, determining the optimal post-MINOCA medication regimen remains uncertain. This review aims to comprehensively address the current state of knowledge, encompassing diagnostic and therapeutic approaches, in the context of MINOCA while also highlighting the evolving landscape and future directions for advancing our understanding and management of this intricate myocardial infarction subtype.

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.

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.

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.

Prognostic impact of secondary prevention medical therapy following myocardial infarction with non-obstructive coronary arteries: a Bayesian and frequentist meta-analysis

AIMS

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a clinical entity with several causes and pathophysiologic mechanisms. Secondary prevention with medical therapy used in patients with obstructive coronary artery disease has unclear benefits in MINOCA patients.

METHODS AND RESULTS

A literature search was conducted until 8 March 2022. Random-effect frequentist and hierarchical Bayesian meta-analyses were performed to assess the clinical impact of medical therapy [renin-angiotensin-aldosterone system (RAAS) inhibitors, statins, dual antiplatelet therapy (DAPT), β-blockers] in MINOCA patients. Outcomes of interest were all-cause mortality and major adverse cardiovascular events (MACE). A total of 12 663 MINOCA patients among five observational studies were analysed. The mean follow-up ranged from 12 to 90 months across studies. In frequentist meta-analysis, statins and β-blockers were associated with a lower risk of all-cause mortality [pooled adjusted hazard ratios (aHRs) 0.53 and 0.81, with 95% confidence intervals (CIs) (0.37-0.76) and (0.67-0.97), respectively]. Only RAAS inhibitors were associated with a lower risk of MACE [pooled aHR: 0.69, with 95% CI (0.53-0.90)]. Bayesian meta-analysis based on informative prior assumptions offered strong evidence only for the benefit of statins on decreasing the risk of all-cause death [Bayes factor (BF): 33.2] and moderate evidence for the benefit of RAAS inhibitors on decreasing the risk of MACE (BF: 9); assigning less informative prior distributions did not affect the results, yet it downgraded the level of evidence to anecdotal.

CONCLUSION

In this meta-analysis, statins and RAAS inhibitors were consistently associated with a lower risk of all-cause mortality and MACE, respectively, in patients with MINOCA. Neutral prognostic evidence was demonstrated for β-blockers and DAPT.

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

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

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.

Prevalence, Clinical Factors, and Outcomes Associated With Myocardial Infarction With Nonobstructive Coronary Artery

BACKGROUND

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is an underrecognized clinical problem in patients presenting with acute coronary syndrome. Various clinical disorders lead to MINOCA thus making treatment and diagnosis a challenge. We aimed to compare the clinical factors and outcomes of patients with MINOCA versus obstructive disease [myocardial infarction due to coronary artery disease (MI-CAD)] in a largely rural health system.

METHODS

Between May 1, 2009 and June 24, 2019, all consecutive ST-segment elevation myocardial infarction patients at Essentia Health were prospectively examined. We categorized patients into MI-CAD (obstructive plaque ≥ 50% with revascularization) or MINOCA (obstructive plaque < 50% with exclusion of other alternative cause). Outcomes included 30-day and 1-year all-cause mortality, 30-day all-cause readmission and 30-day cardiac readmission.

RESULTS

There were 2170 patients included in the study; 2097 (96.6 %) had MI-CAD and 73 (3.4%) met the definition of MINOCA. Within the MINOCA group, the 3 most common presentations were supply-demand mismatch (28.8%), spontaneous coronary artery dissection (9.6%), and other etiology (60.3%). Only 10 (13 %) MINOCA patients had cardiac magnetic resonance imaging studies obtained within 6 months. MINOCA patients were younger 61.6 versus 63.4 years with higher left ventricular function 51.6% versus 50.4% with less likelihood of prior myocardial infarction 4.1% versus 15.5% or congestive heart failure 2.7% versus 6.3% (P < 0.05). Compared with MI-CAD patients, MINOCA patients had similar 30-day mortality (7.1% vs. 8.2%; P = 0.70), 1-year mortality (10.4% vs. 8.2 %; P = 0.55), and 30-day cardiac readmission (8.7% vs. 9.6%; P = 0.29). MINOCA patients were less likely to be discharged on aspirin, betablockers, angiotensin-converting enzyme inhibitor/angiotensin receptor blockers, or statins (P < 0.05).

CONCLUSION

Though there was no difference in readmission and mortality between MINOCA and MI-CAD; use of secondary prevention medications and cardiac rehabilitation referral was low in MINOCA patients. Prospective studies will be relevant to assess effective medical therapy to improve outcomes in MINOCA patients.

Comparison of Patients With Nonobstructive Coronary Artery Disease With Versus Without Myocardial Infarction (from the VA Clinical Assessment Reporting and Tracking [CART] Program)

Comparisons of the outcomes of patients with myocardial infarction with nonobstructive coronary artery disease (MINOCA) and patients with nonobstructive coronary artery disease (CAD) without myocardial infarction (MI) are limited. Here we compare the outcomes of patients with MINOCA and patients with nonobstructive CAD without MI and assess the influence of medical therapy on outcomes in these patients. Veterans who underwent coronary angiography between 2008 to 2017 with nonobstructive CAD were divided into those with or without pre-procedural troponin elevation. Patients with prior revascularization, heart failure, or who presented with cardiogenic shock, STEMI, or unstable angina were excluded. After propensity matching, outcomes were compared between groups. The primary outcome was major adverse cardiovascular events (MACE: mortality, myocardial infarction, and revascularization) within one year: 3,924 patients with nonobstructive CAD and a troponin obtained prior to angiography were identified (n=1,986 with elevated troponin) and restricted to 1,904 patients after propensity-matching. There was a significantly higher risk of MACE among troponin-positive patients compared with those with a negative troponin (HR 2.37; 95% CI, 1.67 to 3.34). Statin (HR 0.32; 95% CI, 0.22 to 0.49) and ACE inhibitor (HR 0.49; 95% CI, 0.32 to 0.75) therapy after angiography was associated with decreased MACE, while P2Y12 inhibitor, calcium-channel and beta-blocker therapy were not associated with outcomes. In conclusion, Veterans with MINOCA are at increased risk for MACE compared with those with nonobstructive CAD and negative troponin at the time of angiography. Specific medications were associated with a reduction in MACE, suggesting an opportunity to explore novel approaches for secondary prevention in this population.

ESC Working Group on Coronary Pathophysiology and Microcirculation position paper on 'coronary microvascular dysfunction in cardiovascular disease'

Although myocardial ischaemia usually manifests as a consequence of atherosclerosis-dependent obstructive epicardial coronary artery disease, a significant percentage of patients suffer ischaemic events in the absence of epicardial coronary artery obstruction. Experimental and clinical evidence highlight the abnormalities of the coronary microcirculation as a main cause of myocardial ischaemia in patients with 'normal or near normal' coronary arteries on angiography. Coronary microvascular disturbances have been associated with early stages of atherosclerosis even prior to any angiographic evidence of epicardial coronary stenosis, as well as to other cardiac pathologies such as myocardial hypertrophy and heart failure. The main objectives of the manuscript are (i) to provide updated evidence in our current understanding of the pathophysiological consequences of microvascular dysfunction in the heart; (ii) to report on the current knowledge on the relevance of cardiovascular risk factors and comorbid conditions for microcirculatory dysfunction; and (iii) to evidence the relevance of the clinical consequences of microvascular dysfunction. Highlighting the clinical importance of coronary microvascular dysfunction will open the field for research and the development of novel strategies for intervention will encourage early detection of subclinical disease and will help in the stratification of cardiovascular risk in agreement with the new concept of precision medicine.

A review of diagnosis, etiology, assessment, and management of patients with myocardial infarction in the absence of obstructive coronary artery disease

Myocardial infarction (MI) in the absence of obstructive coronary artery disease (MINOCA) is prevalent in around 5% of acute myocardial infarction (AMI) presentations. MINOCA is a heterogeneous entity with many different etiologies. It is important for health care providers to familiarize themselves with the disease process, presentation, and possible underlying causes in order to guide appropriate management strategies. In this article, the authors review the contemporary definition, etiologies and assessment, and management for AMI patients with MINOCA.

A Review of the Evidence for Treatment of Myocardial Infarction With Nonobstructive Coronary Arteries

Myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA) is reported in 6% of patients with acute MI referred for catheterization. Because of the complex etiology and a limited amount of evidence, the treatment of MINOCA remains elusive. The etiology of MINOCA manifests from several causes including plaque disruption or erosion, epicardial coronary artery vasospasm, and coronary microvascular dysfunction. In addition, spontaneous coronary artery dissection, takotsubo, and myocarditis have been identified as contributing to the diagnosis of MINOCA. Patients with MINOCA are frequently young, non-white females with fewer traditional risk factors compared with those with an MI caused by obstructive coronary disease. Moreover, women who suffered an MI are 5 times more likely to be diagnosed with MINOCA with a trend for worse outcomes compared with men. The increased recognition/diagnosis of MINOCA has highlighted a gap in our understanding of the treatment of MINOCA. This review identified that there is a paucity of evidence on treatment strategies for patients clinically diagnosed with MINOCA, but more importantly that MINOCA should be viewed as a "syndrome" with many different pathologic causes. This suggests that a standard protocol may not be useful for patients with MINOCA. Given the ongoing debate over the complexity of MINOCA, the main focus in the management of MINOCA should be to identify the underlying mechanism for targeted therapies that may optimize outcomes.

Secondary Prevention Medical Therapy and Outcomes in Patients With Myocardial Infarction With Non-Obstructive Coronary Artery Disease

BACKGROUND

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a heterogeneous entity with relevant long-term major cardiovascular events. Several trials have demonstrated that dual antiplatelet therapy (DAPT), β-blocker, renin-angiotensin-aldosterone system (RAAS) inhibitor and statin therapy improve the prognosis in patients with obstructive myocardial infarction (ob-MI). However, evidence on the best medical therapy for secondary prevention in MINOCA patients is lacking.

PURPOSE

To investigate the effects of secondary prevention treatments at discharge on mid-term outcomes in MINOCA.

METHODS

Patients with acute myocardial infarction (MI) undergoing early coronary angiography between 2016 and 2018 were extracted from a clinical database. The diagnosis of MINOCA was made according to 2016 ESC MINOCA Position Paper criteria. Second-level diagnostic work-up including cardiac magnetic resonance was performed to exclude non-ischemic troponin elevation cause. The relationship between treatments and outcomes was evaluated by using Kaplan-Meier survival analysis and Cox regression models. All confirmed MINOCA were followed in our outpatient clinics. The primary end-points were all-cause mortality, re-hospitalization for MI and a composite outcome including all-cause mortality, hospitalization for MI and ischemic stroke (MACE).

RESULTS

Out of 1,141 AMI who underwent coronary angiography, 134 were initially diagnosed as MINOCA. Patients with MINOCA were less likely to receive secondary prevention treatments than patients with obstructive coronary artery disease (CAD) MI (respectively, 42.1% vs 81.8% for DAPT; 75.5% vs 89.6% for β-blockers; 64.7% vs 80.3% for RAAS inhibitor and 63.9% vs 83% for statins). Based on the diagnostic work-up completed during the first month after discharge, a final sample of 88 patients had confirmed MINOCA. During an average follow-up of 19.35 ± 10.65 months, all-cause mortality occurred in 11 (12.5%) patients, recurrence of MI in 4 (4.5%), and MACE in 15 (17.0%) patients. Patients treated with RAAS inhibitors and statins had a significantly longer survival. On the contrary, no increase in survival was found in patients treated with β-blockers or DAPT. Cox multivariable analysis, including all secondary prevention drugs, showed that only RAAS inhibitors were associated with reduced all cause-mortality and MACE.

CONCLUSION

This prospective study suggests that RAAS inhibitor therapy provides mid-term beneficial effects on outcomes in MINOCA patients; in contrast, dual antiplatelet, β-blocker and statin therapy had no effects on mortality and MACE. These results should be considered preliminary and warrant confirmation from larger studies.

Potential molecular mechanism of ACE gene at different time points in STEMI patients based on genome-wide microarray dataset

Background

This study aimed to investigate the angiotensin converting enzyme (ACE) co-expression genes and their pathways involved in ST-segment elevation myocardial infarction (STEMI) at different time points.

Methods

The array data set of GSE59867 was examined for the ACE co-expression genes in peripheral blood samples from 111 patients with STEMI at four time points (admission, discharge, and 1 and 6 months after MI). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, Gene Ontology (GO) annotation and protein-protein interaction (PPI) of the co-expression genes were determined using online analytical tools. The Cytoscape software was used to create modules and hub genes.

Results

The number of biological processes (BP), cellular components (CC) and molecular functions (MF) was 43, 22 and 24 at admission; 18, 19 and 11 at discharge; 30, 37 and 21 at 1 month after MI; and 12, 19 and 14 at 6 months after MI; respectively. There were 6 BP, 8 CC and 4 MF enriched at every time point. The co-expression genes were substantially enriched in 12, 5, 6 and 14 KEGG pathways at the four time points, respectively, but no KEGG pathway was found to be common in all time points. We identified 132 intersectional co-expression genes (90 positive and 42 negative) from the four time points and 17 BP, 13 CC, 11 MF and 7 KEGG pathways were enriched. In addition, the PPI network contained 129 nodes and 570 edges, and only 1 module was identified to be significantly enriched in just 1 BP (chromatin-mediated maintenance of transcription).

Conclusions

The results of the present study showed that the ACE co-expression genes and their pathways involved in STEMI were significantly different at four different time points. These findings may be helpful for further understanding the functions and roles of ACE in different stages of STEMI, and providing reference for the treatment of STEMI.

Prognosis and Predictors of Mortality in Patients Suffering Myocardial Infarction With Non-Obstructive Coronary Arteries

Background Myocardial infarction with nonobstructive coronary arteries ( MINOCA ) is a heterogeneous disease entity. Its prognosis and predictor of mortality remain unclear. This study aimed to compare the prognosis between MINOCA and myocardial infarction with obstructive coronary artery disease and identify factors related to all-cause death in MINOCA using a nation-wide, multicenter, and prospective registry. Methods and Results Among 13 104 consecutive patients enrolled, patients without previous history of significant coronary artery disease who underwent coronary angiography were selected. The primary outcome was 2-year all-cause death. Secondary outcomes were cardiac death, noncardiac death, reinfarction, and repeat revascularization. Patients with MINOCA (n=396) and myocardial infarction with obstructive coronary artery disease (n=10 871) showed similar incidence of all-cause death (9.1% versus 8.8%; hazard ratio [ HR ], 1.04; 95% CI, 0.74-1.45; P=0.83). Risks of cardiac death, noncardiac death, and reinfarction were not significantly different between the 2 groups ( HR , 0.82; 95% CI , 0.53-1.28; P=0.38; HR , 1.55; 95% CI , 0.93-2.56; P=0.09; HR , 1.23; 95% CI , 0.65-2.31; P=0.38, respectively). MINOCA patients had lower incidence of repeat revascularization (1.3% versus 7.2%; HR , 0.17; 95% CI , 0.07-0.41; P<0.001). Results were consistent after multivariable regression and propensity-score matching. In a multivariate model, several significant predictors of all-cause death of MINOCA were found, including the nonuse of renin-angiotensin system blockers ( HR , 2.63; 95% CI , 1.08-6.25; P=0.033) and statins ( HR , 2.17; 95% CI , 1.04-4.54; P=0.039). Conclusions Patients with MINOCA and those with myocardial infarction with obstructive coronary artery disease had comparable clinical outcomes. Use of renin-angiotensin system blockers and statins was associated with lower mortality in patients with MINOCA .

Prognostic implications of peripheral artery disease in coronary artery disease

Prevalence of peripheral arterial disease in patients with coronary artery disease is considerably higher than in the general population. A graded increase in the risk of major cardiovascular events in a variety of clinical settings is associated with the number of arterial beds affected by peripheral arterial disease. This is not surprising, considering that both coronary artery disease and peripheral arterial disease are linked to a higher prevalence of cardiovascular risk factors and a greater incidence of atherosclerotic burden. Aggressive lipid lowering therapy is associated with less coronary and peripheral arterial disease progression and greater regression. On the contrary, blood pressure therapy should be carefully managed, considering the association of both high and low values of pressure with adverse outcomes.

Nonobstructive Versus Obstructive Coronary Artery Disease in Acute Coronary Syndrome: A Meta-Analysis

Background

Differences in prognosis and baseline clinical presentation have been documented among patient with acute coronary syndrome and coronary artery disease with obstructive (ObCAD) or nonobstructive arteries (NObCAD), but the rates of events largely varied across single studies. We carried out a meta‐analysis to compare the clinical presentation and prognosis of NObCAD versus ObCAD acute coronary syndrome patients, as well as of the subjects with zero versus mild occlusion.

Methods and Results

Searches were made in MedLine, EMBASE, Cochrane databases, and proceedings of international meetings up to June 30, 2015. We compared the risk of events of NObCAD versus ObCAD patients using random‐effect meta‐analyses. We also performed meta‐analyses to estimate the yearly or monthly outcome rates in each single group. In NObCAD and ObCAD patients, respectively, the combined yearly rates were as follows: 2.4% versus 10.1% (all‐cause mortality); 1.2% versus 6.0% (myocardial infarction), 4.0% versus 12.8% (all‐cause mortality plus myocardial infarction), 1.4% versus 5.9% (cardiac death), and 9.2% versus 16.8% (major cardiovascular events). In the studies directly comparing NObCAD versus ObCAD, all of the above outcomes were significantly less frequent in NObCAD subjects (with risk ratios ranging from 0.33 to 0.66). No differences in any outcome rate were observed between mild occlusion (1–49% stenosis) and zero occlusion patients.

Conclusions

NObCAD in patients with acute coronary syndrome has a significantly lower cardiovascular risk at baseline and a subsequent lower likelihood of death or main cardiovascular events. However, these subjects are still at high risk for cardiovascular mortality and morbidity, suggesting potential undertreatment and calling for specific management.

Primary percutaneous coronary intervention in octogenarians

BACKGROUND

Limited data are available on the outcome of primary percutaneous coronary intervention (PCI) in octogenarian patients, as the elderly are under-represented in randomized trials. This study aims to provide insights on clinical characteristics, management and outcome of the elderly and very elderly presenting with STEMI.

METHODS

2225 STEMI patients ≥70years old (mean age 76.8±5.1years and 53.8% men) were admitted into the network of the ISACS-TC registry. Of these patients, 72.8% were ≥70 to 79years old (elderly) and 27.2% were ≥80years old (very-elderly). The primary end-point was 30-day mortality.

RESULTS

Thirty-day mortality rates were 13.4% in the elderly and 23.9% in the very-elderly. Primary PCI decreased the unadjusted risk of death both in the elderly (OR: 0.32, 95% CI: 0.24-0.43) and very-elderly patients (OR: 0.45, 95% CI 0.30-0.68), without significant difference between groups. In the very-elderly hypertension and Killip class ≥2 were the only independent factors associated with mortality; whereas in the elderly female gender, prior stroke, chronic kidney disease and Killip class ≥2 were all factors independently associated with mortality. Factors associated with the lack of use of reperfusion were female gender and atypical chest pain in the very-elderly and in the elderly; in the elderly, however, there were some more factors, namely: history of diabetes, current smoking, prior stroke, Killip class ≥2 and history chronic kidney disease.

CONCLUSIONS

Age is relevant in the prognosis of STEMI, but its importance should not be considered secondary to other major clinical factors. Primary PCI appears to have beneficial effects in the octogenarian STEMI patients.

Optimizing prevention and guideline-concordant care in Montenegro

BACKGROUND

Guidelines recommend use of evidence-based medications in patients discharged after an acute coronary syndrome (ACS). Yet the current rates of adherence in many eastern European countries are unknown.

OBJECTIVE

To determine whether 6month outpatient follow-up after ACS is associated with recommended rates of medication adherence in Montenegro.

METHODS

A prospective analysis was conducted in 585 ACS patients confirmed to be alive after ACS at 6month follow-up. The study was undertaken between 2012 and 2015, from 9 International Survey of Acute Coronary Syndrome in Transitional Countries (ISACS-TC) hospitals in the Montenegro. The primary outcome was guideline-concordant care, defined as 100% compliance with 5 medications: aspirin, clopidogrel, beta-blockers, and statins in ACS patients, and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers [ACEI/ARB] for the subset of patients with left ventricular systolic dysfunction, as assessed by an ejection fraction less than 40% at discharge. In addition to the composite end point, the achievement of each single treatment measure was analyzed. Multivariate predictors of long-term medication adherence were also identified.

RESULTS

Guideline-concordant care (GCC) at discharge increased from 2012 to 2015 (adjusted OR for increase 1.51; CI 0.88-2.52). GCC over 6months was adhered in 73% of patients. In patients who did not achieve GCC, adherence was persistently high with 92.3% for aspirin, 91.3% for statins and 72% for ACE-inhibitors or angiotensin-receptor blockers (ARBs). Adherence was lower for clopidogrel (57.7%) and beta-blockers (64.4%). After adjusting for demographic and clinical differences, in-hospital referral to PCI and ST segment elevation myocardial infarction (STEMI) were associated with greater medication adherence at 6month follow-up.

CONCLUSIONS

In Montenegro, long-term adherence to evidence-based medication after ACS is high. Adherence to guideline-recommended therapies increased over time with participation to the ISACS-TC. The lower achievement of GCC in patients treated medically and in those with non-ST-segment elevation ACS needs particular attention.

Association between comorbidities and absence of chest pain in acute coronary syndrome with in-hospital outcome

BACKGROUND

To evaluate the impact of comorbidities on the management and outcomes of acute coronary syndrome (ACS) patients without chest pain/discomfort (i.e. ACS without typical presentation).

METHODS

Of the 11,458 ACS patients, enrolled by the International Survey of Acute Coronary Syndrome in Transitional Countries (ISACS-TC; ClinicalTrials.gov: NCT01218776), 8.7% did not have typical presentation at the initial evaluation, and 40.2% had comorbidities. The odds of atypical presentation increased proportionally with the number of comorbidities (odds ratio [OR]: 1, no-comorbid; OR: 1.64, 1 comorbidity; OR: 2.52, 2 comorbidities; OR: 4.57, ≥3 comorbidities).

RESULTS

Stratifying the study population by the presence/absence of comorbidities and typical presentation, we found a decreasing trend for use of medications and percutaneous intervention (OR: 1, typical presentation and no-comorbidities; OR: 0.70, typical presentation and comorbidities; OR: 0.23, atypical presentation and no-comorbidities; OR: 0.18, atypical presentation and comorbidities). On the opposite, compared with patients with typical presentation and no-comorbidities (OR: 1, referent), there was an increasing trend (p<0.001) in the risk of death (OR: 2.00, OR: 2.52 and OR: 4.83) in the above subgroups. However, after adjusting for comorbidities, medications and invasive procedures, atypical presentation was not a predictor of in-hospital death. Independent predictors of poor outcome were history of stroke (OR: 2.04), chronic kidney disease (OR: 1.57), diabetes mellitus (OR: 1.49) and underuse of invasive procedures.

CONCLUSIONS

In the ISACS-TC, atypical ACS presentation was often associated with comorbidities. Atypical presentation and comorbidities influenced underuse of in-hospital treatments. The latter and comorbidities are related with poor in-hospital outcome, but not atypical presentation, per se.

Vasotonic Angina as a Cause of Myocardial Ischemia in Women

The frequency, presentation, prognosis, and treatment of myocardial ischemia differ in men and women. A large proportion of women who have "normal" coronary arteries on angiography without any significant evidence of flow-limiting disease also have biochemical or imaging evidence of myocardial ischemia. In these women it is believed to be a dysfunction of coronary microcirculation and/or macrocirculation, or vasotonic angina (VA), that leads to abnormal vasoconstriction, and potentially to myocardial infarction, ventricular arrhythmias, and sudden death. Despite having a "normal" or near normal coronary angiography, these women should therefore undergo additional testing with acetylcholine to assess endothelial function. Long-term survival is believed to be relatively good. Predictors of poorer prognosis include documentation of severe endothelial dysfunction and presence of concurrent angiographycally visible coronary atherosclerosis. Because atherosclerosis is common in patients with VA, medical and lifestyle interventions for preventing or treating atherosclerosis should be implemented when appropriate. Angiotensin converting enzyme inhibitors are the mainstays of medical therapy for VA. Other agents have been tried with variable success, including beta-blockers. There are no available data on any specific treatment of VA in women (versus men).

Evaluation of the Methods and Management of Acute Coronary Events (EMMACE)-3: protocol for a longitudinal study

INTRODUCTION

Patients with cardiovascular disease are living longer and are more frequently accessing healthcare resources. The Evaluation of the Methods and Management of Acute Coronary Events (EMMACE)-3 national study is designed to improve understanding of the effect of quality of care on health-related outcomes for patients hospitalised with acute coronary syndrome (ACS).

METHODS AND ANALYSIS

EMMACE-3 is a longitudinal study of 5556 patients hospitalised with an ACS in England. The study collects repeated measures of health-related quality of life, information about medications and patient adherence profiles, a survey of hospital facilities, and morbidity and mortality data from linkages to multiple electronic health records. Together with EMMACE-3X and EMMACE-4, EMMACE-3 will assimilate detailed information for about 13 000 patients across more than 60 hospitals in England.

ETHICS AND DISSEMINATION

EMMACE-3 was given a favourable ethical opinion by Leeds (West) Research Ethics committee (REC reference: 10/H131374). On successful application, study data will be shared with academic collaborators. The findings from EMMACE-3 will be disseminated through peer-reviewed publications, at scientific conferences, the media, and through patient and public involvement.

STUDY REGISTRATION NUMBER

ClinicalTrials.gov Identifier: NCT01808027. Information about the study is also available at EMMACE.org.

Association of Angiotensin converting enzyme gene insertion / deletion polymorphism with risk of ischemic heart disease in a population of smokers in southern India

BACKGROUND

Ischemic heart disease (IHD) remains a major public health problem nationally and internationally. Smoking is a major risk factor for IHD.The deletion (D) allele of the angiotensin converting enzyme (ACE) gene polymorphism has been associated with hypertension, ischemic stroke and myocardial infarction. The present study was carried out to determine the association of the ACE gene insertion/deletion (I/D) polymorphism in IHD patients with and without smoking.

MATERIALS AND METHODS

One hundred seven male IHD patients admitted consecutively in the Cardiology unit of a Government Hospital and 100 age and sex matched healthy controls were enrolled in this study.The patients were further divided into smokers and nonsmokers. All the subjects were checked for I/D polymorphism of ACE gene, which is mapped to 17q23.3 with OMIM no 106180, by polymerase chain reaction (PCR). The subjects were also investigated for lipid profile and ejection fraction (EF).

RESULTS

We found significant difference in the distribution of D allele between patients and controls (p=0.009, OR 1.69, 95% CI 1.139 to 2.517).The significantly lower EF (p<0.001) was suggestive of greater cardiovascular compromise in smokers. The frequency of ID genotype was significantly associated with cases compared to controls (p=0.012, OR 2.054, 95% CI 1.1694-3.624) but was not significantly associated with smokers as compared to nonsmokers.

CONCLUSION

We infer significant association of D allele with IHD. The smokers with ID genotype should be put on prophylactic ACE inhibitor therapy to prevent the morbidity and mortality associated with IHD.