Survival in Patients With Suspected Myocardial Infarction With Nonobstructive Coronary Arteries: A Comprehensive Systematic Review and Meta-Analysis From the MINOCA Global Collaboration

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.

Ejection Fraction-Related Differences of Baseline Characteristics and Outcomes in Troponin-Positive Patients without Obstructive Coronary Artery Disease

Background: The development and course of myocardial infarction with non-obstructive coronary artery (MINOCA) disease is still not fully understood. In this study, we aimed to examine the baseline characteristics of in-hospital outcomes and long-term outcomes of a cohort of troponin-positive patients without obstructive coronary artery disease based on different left ventricular ejection fractions (LVEFs). Methods and results: We included a cohort of 254 patients (mean age: 64 (50.8-75.3) years, 120 females) with suspected myocardial infarction and no obstructive coronary artery disease (MINOCA) in our institutional database between 2010 and 2021. Among these patients, 170 had LVEF ≥ 50% (84 females, 49.4%), 31 patients had LVEF 40-49% (15 females, 48.4%), and 53 patients had LVEF < 40% (20 females, 37.7%). The mean age in the LVEF ≥ 50% group was 61.5 (48-73) years, in the LVEF 40-49% group was 67 (57-78) years, and in the LVEF < 40% group was 68 (56-75.5) years (p = 0.05). The mean troponin value was highest in the LVEF < 40% group, at 3.8 (1.7-4.6) µg/L, and lowest in the LVEF ≥ 50% group, at 1.1 (0.5-2.1) µg/L (p = 0.05). Creatine Phosphokinase (CK) levels were highest in the LVEF ≥ 50% group (156 (89.5-256)) and lowest in the LVEF 40-49% group (127 (73-256)) (p < 0.05), while the mean BNP value was lowest in the LVEF ≥ 50% group (98 (48-278) pg/mL) and highest in the <40% group (793 (238.3-2247.5) pg/mL) (p = 0.001). Adverse in-hospital cardiovascular events were highest in the LVEF < 40% group compared to the LVEF 40-49% group and the LVEF ≥ 50% group (56% vs. 55% vs. 27%; p < 0.001). Over a follow-up period of 6.2 ± 3.1 years, the all-cause mortality was higher in the LVEF < 40% group compared to the LVEF 40-49% group and the LVEF ≥ 50% group. Among the different factors, LVEF < 40% and LVEF 40-49% were associated with an increased risk of in-hospital cardiovascular events in the multivariable Cox regression analysis. Conclusions: LVEF has different impacts on in-hospital cardiovascular events in this cohort. Furthermore, LVEF influences long-term all-cause mortality.

Sex differences in patients presenting with acute coronary syndrome: a state-of-the-art review

Cardiovascular conditions in the spectrum of acute coronary syndromes are characterized by sex differences with regard to pathophysiology, risk factors, clinical presentation, invasive and pharmacologic treatment, and outcomes. This review delves into these differences, including specific subsets like myocardial infarction with non-obstructed coronary arteries or Spontaneous Coronary Artery Dissection, and alternative diagnoses like Takotsubo cardiomyopathy or myocarditis. Moreover, practical considerations are enclosed, on how a sex-specific approach should be integrated in clinical practice: in fact, personal history should focus on female-specific risk factors, and hormonal status and hormonal therapy should be assessed. Moreover, physical and psychological stressors should be investigated, particularly in the event of Spontaneous Coronary Artery Dissection or Takotsubo cardiomyopathy.

Nonobstructive epicardial coronary artery disease: an evolving concept in need of diagnostic and therapeutic guidance

For decades, we have been treating patients presenting with angina and concerning electrocardiographic changes indicative of ischemia or injury, in whom no culprit epicardial coronary stenosis was found during diagnostic coronary angiography. Unfortunately, the clinical outcomes of these patients were not better than those with recognized obstructive coronary disease. Improvements in technology have allowed us to better characterize these patients. Consequently, an increasing number of patients with ischemia and no obstructive coronary artery disease (INOCA) or myocardial infarction in the absence of coronary artery disease (MINOCA) have now gained formal recognition and are more commonly encountered in clinical practice. Although both entities might share functional similarities at their core, they pose significant diagnostic and therapeutic challenges. Unless we become more proficient in identifying these patients, particularly those at higher risk, morbidity and mortality outcomes will not improve. Though this field remains in constant flux, data continue to become available. Therefore, we thought it would be useful to highlight important milestones that have been recognized so we can all learn about these clinical entities. Despite all the progress made regarding INOCA and MINOCA, many important knowledge gaps continue to exist. For the time being, prompt identification and early diagnosis remain crucial in managing these patients. Even though we are still not clear whether intensive medical therapy alters clinical outcomes, we remain vigilant and wait for more data.

Sex-specific and ethnicity-specific differences in MINOCA

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

The impact of diabetes mellitus on the outcome of troponin-positive patients with non-obstructive coronary arteries

Background

Diabetes mellitus is a major cardiovascular risk factor for the development of coronary artery disease, but knowledge about the impact of diabetes mellitus on the outcome of patients with myocardial infarction with non-obstructive coronary arteries is limited. The aim of this study was to investigate the prognostic impact of diabetes mellitus on in- and out-of-hospital adverse events in troponin-positive patients with non-obstructive coronary arteries.

Methods and Results

A total of 373 troponin-positive patients with non-obstructive coronary arteries between 2010 and 2021 at Bergmannsheil University Hospital Bochum were enrolled, including 65 diabetics and 307 nondiabetics. The median follow-up was 6.2 years. The primary study end point was a composite of in-hospital major adverse cardiovascular events (MACE). Secondary endpoints covered MACE during follow-up.Mean age of the study cohort was 62.9 years and 49.3 % were male. Although the overall rate of in-hospital MACE was higher in diabetics (41.5 %) than in non-diabetics (33.9 %), this difference did not reach statistical significance (p = 0.240). The in-hospital mortality rate was low in both groups, 0 % of diabetes group versus 2.9 % of non-diabetic patients. During follow-up, diabetic patients had a significantly higher rate of MACE (51.9 % vs. 31.1 %, p = 0.004) and a significantly higher all-cause mortality rate than non-diabetic patients (42.3 % vs. 20.1 %, p < 0.001).

Conclusion

Our study reveals that the impact of diabetes mellitus on cardiovascular outcomes in troponin-positive patients with non-obstructive coronary arteries intensifies over the long term, leading to increased rates of both cardiovascular adverse events and overall mortality.

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.

Prognostic implications of stress hyperglycemia ratio in patients with myocardial infarction with nonobstructive coronary arteries

BACKGROUND

The role of stress hyperglycemia in acute myocardial infarction (AMI) has long been emphasized. Recently, the stress hyperglycemia ratio (SHR), a novel index reflecting an acute glycemia rise, has shown a good predictive value in AMI. However, its prognostic power in myocardial infarction with nonobstructive coronary arteries (MINOCA) remains unclear.

METHODS

In a prospective cohort of 1179 patients with MINOCA, relationships between SHR levels and outcomes were analyzed. SHR was defined as acute-to-chronic glycemic ratio using admission blood glucose (ABG) and glycated hemoglobin. The primary endpoint was defined as major adverse cardiovascular events (MACE), including all-cause death, nonfatal MI, stroke, revascularization, and hospitalization for unstable angina or heart failure. Survival analyses and receiver-operating characteristic (ROC) curve analyses were performed.

RESULTS

Over the median follow-up of 3.5 years, the incidence of MACE markedly increased with higher SHR tertile levels (8.1%, 14.0%, 20.5%; p < 0.001). At multivariable Cox analysis, elevated SHR was independently associated with an increased risk of MACE (HR 2.30, 95% CI: 1.21-4.38, p = 0.011). Patients with rising tertiles of SHR also had a significantly higher risk of MACE (tertile 1 as reference; tertile 2: HR 1.77, 95% CI: 1.14-2.73, p = 0.010; tertile 3: HR 2.64, 95% CI: 1.75-3.98, p < 0.001). SHR remained a robust predictor of MACE in patients with and without diabetes; whereas ABG was no longer associated with the MACE risk in diabetic patients. SHR showed an area under the curve of 0.63 for MACE prediction. By incorporating SHR to TIMI risk score, the combined model further improved the discrimination for MACE.

CONCLUSIONS

The SHR independently confers the cardiovascular risk after MINOCA, and may serve as a better predictor than glycemia at admission alone, particularly in those with diabetes.KEY MESSAGESStress hyperglycemia ratio (SHR) is independently associated with the prognosis in a distinct population with myocardial infarction with nonobstructive coronary arteries (MINOCA).SHR is a better predictor of prognosis than admission glycemia alone, especially in diabetic patients with MINOCA.SHR may serve as a prognostic marker for risk stratification as well as a potential target for tailored glucose-lowering treatment in MINOCA.

Medium-Term Prognostic Implications of Cardiac Magnetic Resonance Imaging in Patients With Myocardial Infarction With Nonobstructive Coronary Arteries (MINOCA): A Systematic Review and Meta-Analysis

BACKGROUND

This study aimed to evaluate the medium-term prognostic implications of cardiac magnetic resonance (CMR) imaging in patients with myocardial infarction with non-obstructive coronary arteries (MINOCA).

METHODS

A systematic literature search of Embase, PubMed, and The Cochrane Library was performed. Eligible studies reported outcomes of CMR-assessed MINOCA with a mean follow-up period of >6 months. The primary endpoint was all-cause death. Secondary endpoints included cardiac death, reinfarction, and cardiovascular rehospitalisation. The pooled effect sizes with 95% confidence interval (CIs) were estimated using a random effect model.

RESULTS

A total of 3,050 patients from twenty-one studies were included in the meta-analysis. The prevalence of myocarditis, "true" myocardial infarction, Takotsubo cardiomyopathy, and normal CMR imaging was 36%, 25%, 14%, and 19%, respectively. Pooled data showed that the annualised event rates for all-cause mortality, cardiac mortality, reinfarction, and cardiovascular rehospitalisation were 1.01% (95% CI 0.59%-1.51%), 0.06% (95% CI 0.00%-0.39%), 0.68% (95% CI 0.18%-1.38%), and 5.67% (95% CI 3.11%-8.85%), respectively. Compared with patients with a diagnosis of myocarditis on CMR, patients with Takotsubo cardiomyopathy (RR 7.11; 95% CI 3.04-16.66) and "true" myocardial infarction (RR 3.82; 95% CI 1.65-8.86) were associated with a significantly higher risk of all-cause mortality, whereas a similar risk of all-cause mortality was observed in patients with normal imaging (RR 1.01; 95% CI 0.28-3.59). No association was found between CMR diagnoses and the risk of secondary endpoints in MINOCA.

CONCLUSIONS

In patients with MINOCA assessed by CMR, the overall absolute incidence rates of mortality and reinfarction were low. However, certain imaging diagnoses were associated with a higher risk of all-cause mortality, with most deaths attributed to non-cardiac causes. Additionally, these patients experienced a high burden of cardiovascular rehospitalisation.

REGISTRATION

PROSPERO (CRD42022323615).

MINOCA biomarkers: Non-atherosclerotic aspects

Myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) is an important subtype of myocardial infarction. Although comprising less than 50% stenosis in the main epicardial coronary arteries, it constitutes a severe health risk. A variety of approaches have been recommended, but definitive diagnosis remains elusive. In addition, the lack of a comprehensive understanding of underlying pathophysiology makes clinical management difficult and unpredictable. This review highlights ongoing efforts to identify relevant biomarkers in MINOCA to improve diagnosis, individualize treatment and better predict outcomes.

Predictive value of Killip classification in MINOCA patients

BACKGROUND

Killip classification is a practical clinical tool for risk stratification in patients with acute myocardial infarction (AMI). However, its prognostic role in myocardial infarction with non-obstructive coronary artery (MINOCA) is still poorly explored. Our purpose was to evaluate the prognostic role of high Killip class in the specific setting of MINOCA and compare the results with a cohort of patients with obstructive coronary arteries myocardial infarction (MIOCA).

METHODS

This study included 2455 AMI patients of whom 255 were MINOCA. We compared the Killip classes of MINOCA with those of MIOCA and evaluated the prognostic impact of a high Killip class, defined if greater than I, on both populations' outcome. Short-term outcomes included in-hospital death, re-AMI and arrhythmias. Long-term outcomes were all-cause mortality, re-AMI, stroke, heart failure (HF) hospitalization and the composite endpoint of MACE.

RESULTS

Killip class >1 occurred in 25 (9.8%) MINOCA patients compared to 327 (14.9%) MIOCA cases. In MINOCA subjects, a high Killip class was associated with a greater in-hospital mortality (p = 0.002) and, at long term follow-up, with a three-fold increased mortality (p = 0.001) and a four-fold risk of HF hospitalization (p = 0.003). Among MINOCA, a high Killip class was identified as a strong independent predictor of MACE occurrence [HR 2.66, 95% CI (1.25-5.64), p = 0.01] together with older age and worse kidney function while in MIOCA population also left ventricular ejection fraction and troponin value predicted MACE.

CONCLUSIONS

Killip classification confirmed its prognostic impact on short- and long-term outcomes also in a selected MINOCA population, which still craves for a baseline risk stratification.

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.

Sex- and age-related differences in outcomes of patients with acute myocardial infarction: MINOCA vs. MIOCA

AIMS

The aim of the study is to evaluate the impact of sex on acute myocardial infarction (AMI) patients' clinical presentation and outcomes, comparing those with non-obstructive and obstructive coronary arteries (MINOCA vs. MIOCA).

METHODS AND RESULTS

We enrolled 2455 patients with AMI undergoing coronary angiography from January 2017 to September 2021. Patients were divided according to the type of AMI and sex: male (n = 1593) and female (n = 607) in MIOCA and male (n = 87) and female (n = 168) in MINOCA. Each cohort was further stratified based on age (≤/> 70 years). The primary endpoint (MAE) was a composite of all-cause death, recurrent AMI, and hospitalization for heart failure (HF) at follow-up. Secondary outcomes included all-cause and cardiovascular death, recurrent AMI, HF re-hospitalization, and stroke. MINOCA patients were more likely to be females compared with MIOCA ones (P < 0.001). The median follow-up was 28 (15-41) months. The unadjusted incidence of MAE was significantly higher in females compared with males, both in MINOCA [45 (26.8%) vs. 12 (13.8%); P = 0.018] and MIOCA cohorts [203 (33.4%) vs. 428 (26.9%); P = 0.002]. Age was an independent predictor of MAE in both cohorts. Among MINOCA patients, females ≤70 years old had a higher incidence of MAE [18 (23.7%) vs. 4 (5.9%); P = 0.003] compared with male peers, mainly driven by a higher rate of re-hospitalization for HF (P = 0.045) and recurrence of AMI (P = 0.006). Only in this sub-group of MINOCA patients, female sex was an independent predictor of MAE (hazard ratio = 3.09; 95% confidence interval: 1.02-9.59; P = 0.040). MINOCA females ≤70 years old had worse outcomes than MIOCA female peers.

CONCLUSION

MINOCA females ≤70 years old had a significantly higher incidence of MAE, compared with males and MIOCA female peers, likely due to the different pathophysiology of the ischaemic event.

TRIAL REGISTRATION

Data were part of the ongoing observational study 'AMIPE: Acute Myocardial Infarction, Prognostic and Therapeutic Evaluation' (ClinicalTrials.gov Identifier: NCT03883711).

Health-related quality-of-life up to one year after myocardial infarction with non-obstructive coronary arteries

AIMS

Patients with Myocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA) are a heterogenous group and previous studies indicate a decreased Health-related quality-of-life (HRQoL) compared with patients with myocardial infarction with obstructive coronary artery disease and healthy individuals. However, longitudinal data are scarce. Therefore, the aim was to explore HRQoL among patients with MINOCA during a one-year period after the acute event in comparison with a group of healthy individuals and to describe HRQoL in patients with Takotsubo Syndrome (TTS).

METHODS AND RESULTS

Patients with MINOCA were recruited from five hospitals in the Stockholm region (SMINC-2 study, clinical trials: NCT2318498). Patients responded to the HRQoL questionnaire RAND-36 between days 2-4, after 6 and 12 months respectively. A sample of population-based individuals was used as a comparison group. A total of 142 MINOCA patients, (70% women) mean age of 56 years, responded. A population-based sample of 317 volunteers (66% women) mean age of 57 years. Patients with MINOCA scored lower than the comparison group in the domains role functioning physical, social functioning, and role functioning emotional (P = 0.01-0.02) at 12 months. In these domains of HRQoL there was no improvement in MINOCA patients during 12 months follow-up. In the domains of energy/fatigue vitality and emotional well-being the scores improved and were similar to the comparison group at 12 months. Patients with TTS scored generally lower on RAND-36 than MINOCA patients without TTS.

CONCLUSION

Physical, social, and emotional functioning did not improve during the first year after MINOCA, indicating a need for increased follow-up including psychological support.

Performance of Prognostic Scoring Systems in MINOCA: A Comparison among GRACE, TIMI, HEART, and ACEF Scores

Background: the prognosis of patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) is not benign; thus, prompting the need to validate prognostic scoring systems for this population. Aim: to evaluate and compare the prognostic performance of GRACE, TIMI, HEART, and ACEF scores in MINOCA patients. Methods: A total of 250 MINOCA patients from January 2017 to September 2021 were included. For each patient, the four scores at admission were retrospectively calculated. The primary outcome was a composite of all-cause death and acute myocardial infarction (AMI) at 1-year follow-up. The ability to predict 1-year all-cause death was also tested. Results: Overall, the tested scores presented a sub-optimal performance in predicting the composite major adverse event in MINOCA patients, showing an AUC ranging between 0.7 and 0.8. Among them, the GRACE score appeared to be the best in predicting all-cause death, reaching high specificity with low sensitivity. The best cut-off identified for the GRACE score was 171, higher compared to the cut-off of 140 generally applied to identify high-risk patients with obstructive AMI. When the scores were tested for prediction of 1-year all-cause death, the GRACE and the ACEF score showed very good accuracy (AUC = 0.932 and 0.828, respectively). Conclusion: the prognostic scoring tools, validated in AMI cohorts, could be useful even in MINOCA patients, although their performance appeared sub-optimal, prompting the need for risk assessment tools specific to MINOCA patients.

Do Chest Pain Characteristics in Patients with Acute Myocardial Infarction Differ between Those with and without Obstructive Coronary Artery Disease?

The universal definition of acute myocardial infarction (MI) requires both evidence of myocardial injury and myocardial ischaemia. In MINOCA (MI with non-obstructive coronary arteries), patients must fulfil this MI criteria, but is their chest pain similar to those who have MI with obstructive CAD (MICAD)? This study compares prospectively collected chest pain features between patients with MINOCA and MICAD. Utilising the Coronary Angiogram Database of South Australia (CADOSA), consecutive MI patients were categorized as MINOCA or MICAD based on angiographic findings. Chest pain data were collected via direct patient interviews by trained staff members. Of 6811 consecutive patients fulfilling a clinical MI diagnosis, 411 (6.0%) were MINOCA, and 5948 MICAD. The MINOCA patients were younger, more often female and had less cardiovascular risk factors than those with MICAD. There were no significant differences in chest pain characteristics between the MINOCA and MICAD cohorts in relation to pain location, quality, associated symptoms, or duration. In conclusion, MINOCA patients have chest pain characteristics that are indistinguishable from MICAD patients, suggesting that their pain is ischaemic in nature. Thus, in the presence of positive myocardial injury markers, ischaemic chest pain fulfils the universal criteria for MI, despite the absence of obstructive coronary artery disease.

Role of Cardiac Magnetic Resonance Imaging and Troponin T in Definitive Diagnosis of Myocardial Infarction With Nonobstructive Coronary Arteries (MINOCA)

BACKGROUND

It is unknown whether the degree of high-sensitivity troponin T (hsTropT) elevation in patients with suspected myocardial infarction without obstructive coronary arteries (MINOCA) presentations can help predict the likelihood of an abnormal cardiac magnetic resonance (CMR) scan. In this study we describe the diagnostic utility of CMR in patients with MINOCA and assesses the effect of peak hsTropT levels at presentation on CMR diagnostic yield.

METHODS

Records of consecutive patients (n = 1407) referred for CMR at a tertiary referral hospital between January 2016 and September 2021 were reviewed. A total of 70 patients met the criteria of MINOCA including ischemic chest pain, elevated peak hsTropT, and nonobstructive coronary artery disease (< 50% stenosis). The peak hsTropT levels within 72 hours of admission were identified. CMR images were generated using a 3.0 T Siemens scanner. Predictors of having an abnormal CMR were evaluated.

RESULTS

CMR established a diagnosis in 71% (n = 50) of patients, with the most common CMR diagnosis being myopericarditis (n = 27; 39%). Time to CMR was an independent predictor of a normal CMR scan (odds ratio, 0.98; 95% confidence interval, 0.97-0.999). Peak hsTropT had a high diagnostic accuracy for identifying patients with an abnormal CMR scan (area under the receiver operator characteristic curve, 0.81; P < 0.001). The optimal hsTropT cutoff was 166 ng/L, with 72% sensitivity and specificity. A troponin value ≥ 166 ng/L was independently predictive of an abnormal CMR scan (odds ratio, 4.76; 95% confidence interval, 1.32-17.11).

CONCLUSIONS

HsTropT and early CMR imaging are independently predictive of an abnormal CMR scan in patients with MINOCA. Additionally, the use of a hsTropT cutoff provides incremental predictive value to clinical parameters and time to CMR scanning in determining an abnormal scan.

The Comparison of Predicting Factors and Outcomes of MINOCA and STEMI Patients in the 5-Year Follow-Up

The long-term outcomes of patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) are still not well known. This study aimed to compare the characteristics and outcomes between MINOCA and STEMI patients in a 5-year follow-up. Between 2010 and 2015 we identified 3171 coronary angiography procedures performed due to acute coronary syndrome, from which 153 had a working MINOCA diagnosis, and the final diagnosis of MINOCA was ascribed to 112 (5.8%) patients. Additionally, we matched 166 patients with STEMI and obstructive coronary arteries as the reference group. In MINOCA patients (mean age of 63 years), there were more females (60% vs. 26%, p < 0.001), and patients presented most frequently with NSTEMI (83.9%). Patients with MINOCA had more frequent atrial fibrillation (22% vs. 5.4%, p < 0.001) and higher left ventricular ejection fraction (59 ± 10% vs. 54 ± 10%, p < 0.001) compared to STEMI patients. We observed only a trend for a higher rate of MACE in STEMI patients at 5 years (11.6% vs. 18.7%, HR 1.82, 95% CI 0.91-3.63, p = 0.09). In multivariable Cox regression, only beta-blocker use was a protective factor (a trend observed), with HR 0.33, 95% CI 0.10-1.15, p = 0.082 of future MACE. The outcomes of MINOCA and STEMI patients were comparable in the 5-year follow-up.

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.

Role of Cardiac Magnetic Resonance Imaging in the Evaluation of MINOCA

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

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

Aims

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

Methods and results

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

Conclusion

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

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

Background

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

Methods

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

Results

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

Conclusions

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

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.

Effect of nonobstructive coronary stenosis on coronary microvascular dysfunction and long-term outcomes in patients with INOCA

BACKGROUND

Ischemic pain with no-obstructive coronary artery (INOCA) is clinically significant and defined by nonobstructive coronary stenosis <50%. Coronary microvascular dysfunction (CMD) is a relevant cause associated with adverse outcomes.

OBJECTIVES

Investigated the effect of no-stenosis (0% stenosis) and non-obstructive (0% < stenosis < 50%) on the prognostic impact of CMD in INOCA.

METHOD

A retrospective study assessed the coronary microvascular function in 151 INOCA patients who underwent invasive angiography by the coronary angiography-derived index of microcirculation-resistance (caIMR). CZT-SPECT was performed to evaluate myocardial perfusion imaging (MPI) abnormalities. Chi-square test/Fisher exact test, Student t-test, Kaplan-Meier curve, and Uni-multivariable Cox proportional models were used for analysis. Clinical outcomes were major adverse cardiovascular events (MACE) during a median follow-up of 35 months.

RESULT

No-stenosis was present in 71 (47%) INOCA patients, and 80 (53%) were with nonobstructive. CMD (caIMR ≥ 25) was more prevalent in patients with no-stenosis than nonobstructive (76.1% vs. 48.8%, p = .001), along with abnormal MPI (39.4% vs. 22.5%, p = .024). The MACE rates were not different between no-stenosis and nonobstructive stenosis. CMD showed an increased risk of MACE for all INOCA. No-stenosis with CMD had the worst prognosis. Cox regression analysis identified CMD and abnormal MPI as predictors of MACE in all INOCA and patients with no-stenosis. However, no-stenosis and nonobstructive stenosis were not predictors of MACE in INOCA.

CONCLUSION

CMD was more frequently present in INOCA with no-stenosis. However, there was no difference in long-term clinical outcomes between no-stenosis and nonobstructive stenosis. CMD could independently predict poor outcomes in INOCA, particularly in patients with no-stenosis.

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

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

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

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

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Myocardial infarction with non-obstructive coronary arteries (MINOCA)

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

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.

Clinical Characteristics Predicting Worse Long-Term Outcomes in Patients with Myocardial Infarction and Non-Obstructive Coronary Arteries (MINOCA)

Non-obstructive coronary artery disease occurs in 3.5–15% of patients presenting with acute myocardial infarction. This group of patients has a poor prognosis. Identification of factors that predict worse outcomes in myocardial infarction with non-obstructive coronary arteries (MINOCA) is therefore important. Patients with a diagnosis of MINOCA (n = 110) were enrolled in this single-center, retrospective registry. Follow-up was performed 12, 24 and 36 months after discharge. The primary composite endpoint was defined as myocardial infarction, coronary revascularization, stroke or TIA, all-cause death, or hospital readmission due to any cardiovascular event. The mean age of the study group was 64.9 (± 13.5) years and 38.2% of patients were male. The occurrence of the primary composite endpoint was 36.4%. In a COX proportional hazards model analysis, older age (p = 0.027), type 2 diabetes (p = 0.013), history of neoplasm (p = 0.004), ST-segment depression (p = 0.018) and left bundle branch block/right bundle branch block (p = 0.004) by ECG on discharge, higher Gensini score (p = 0.022), higher intraventricular septum (p = 0.007) and posterior wall thickness increases (p = 0.001) were shown to be risk factors for primary composite endpoint occurrence. Our study revealed that several factors such as older age, type 2 diabetes, ST-segment depression and LBBB/RBBB in ECG on discharge, higher Gensini score, and myocardial hypertrophy and history of neoplasm may contribute to worse clinical outcomes in MINOCA patients.

Do Patients with Myocardial Infarction with Non-Obstructive Coronary Arteries Have Similar Prognosis Compared to Ones with MI-CAD?

Acute myocardial infarction (AMI) is a leading cause of morbidity and mortality worldwide and it is primarily caused by acute plaque disruption and coronary occlusion. Recent studies suggest that myocardial infarction with non-obstructive coronary arteries (MINOCA) also occurs but the underlying mechanisms have not been fully understood until recently. The evidence also suggests that the clinical outcomes of patients presenting with MINOCA are similar to AMI patients with obstructive coronary artery disease (MI-CAD), including all-cause mortality and major adverse cardiovascular events. The present narrative review considers the risk factors, pathological changes, and outcomes associated with MINOCA and compares them with MI-CAD.

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.

Sleep Quality, Sleep Duration, and the Risk of Adverse Clinical Outcomes in Patients With Myocardial Infarction With Non-obstructive Coronary Arteries

Background

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a heterogeneous entity with varying underlying etiologies and occurs in ~5–10% of patients with acute myocardial infarction. Sleep disorders and short sleep duration are common phenomena experienced by patients with coronary heart disease and are associated with poor clinical outcomes. However, the association between sleep quality, sleep duration, and the MINOCA prognosis is less clear.

Methods

We performed a prospective observational study of 607 patients with MINOCA between February 2016 and June 2018. The mean follow-up period was 3.9 years. Sleep quality and sleep duration were measured by the Chinese version of the Pittsburgh Sleep Quality Index. The primary endpoint was all-cause mortality, and the secondary endpoint was major adverse cardiovascular events (MACE), defined as a composite of cardiovascular death, non-fatal myocardial infarction, stroke and heart failure hospitalization.

Results

During the follow-up period, all-cause death occurred in 69 participants and 105 participants developed MACE. The Kaplan–Meier survival analysis demonstrated a significant association between poor sleep quality and all-cause mortality (log-rank P = 0.005) and MACE (log-rank P = 0.004). Multivariable Cox regression model indicated that poor sleep quality was an independent predictor of all-cause mortality as well as MACE [adjusted hazard ratio (HR) = 1.649; 95% confidence interval (CI), 1.124–2.790; P &lt; 0.001; and adjusted HR = 1.432; 95% CI, 1.043–2.004; P = 0.003, respectively]. For sleep duration, short sleep duration (&lt;6 h/d) was significantly associated with an increased risk of all-cause mortality and MACE (adjusted HR = 1.326; 95% CI, 1.103–1.812; P = 0.004; and adjusted HR = 1.443; 95% CI, 1.145–1.877; P &lt; 0.001, respectively), whereas long sleep duration was not (&gt;8 h/d). A poorer sleep profile (including poor sleep quality and short sleep duration) was associated with a 149.4% increased risk of death (HR = 2.494; 95% CI, 1.754–4.562; P &lt; 0.001) and a 96.7% increased risk of MACE (HR = 1.967; 95% CI, 1.442–3.639; P &lt; 0.001) than those with neither.

Conclusion

Sleep disorders were common among Chinese patients with MINOCA. Poor sleep quality and short sleep duration were independently associated with an increased risk of all-cause mortality and MACE in the MINOCA population. Meanwhile, a poor sleep profile has an additive effect with regard to cardiovascular risks; in these populations, efforts should be made to improve both sleep quality and sleep duration for secondary cardiovascular prevention.

Clinical Trial Registration

http://www.chictr.org.cn, identifier: ChiCTR2000040701.

Long-term outcomes of early-onset myocardial infarction with non-obstructive coronary artery disease (MINOCA)

BACKGROUND

Acute myocardial infarction with non-obstructive coronary artery disease (MINOCA) is frequent in patients experiencing an early-onset MI, but data concerning its long-term prognosis are limited and conflicting.

METHODS

The Italian Genetic Study on Early-onset MI enrolled 2000 patients experiencing a first MI before the age of 45 years, and had a median follow-up of 19.9 years. The composite primary endpoint was cardiovascular (CV) death, non-fatal MI, and non-fatal stroke (MACE); the secondary endpoint was rehospitalisation for coronary revascularisation.

RESULTS

MINOCA occurred in 317 patients (15.9%) and, during the follow-up, there was no significant difference in MACE rates between them and the patients with obstructive coronary artery disease (MICAD: 27.8% vs 37.5%; adjusted hazard ratio [HR] 0.79, 95% confidence interval [CI] 0.57-1.09;p = 0.15). The CV death rate was lower in the MINOCA group (4.2% vs 8.4%, HR 0.26, 95%CI 0.08-0.86;p = 0.03), whereas the rates of non-fatal reinfarction (17.3% vs 25.4%; HR 0.76, 95%CI 0.52-1.13;p = 0.18), non-fatal ischemic stroke (9.5% vs 3.7%; HR 1.79, 95%CI 0.87-3.70;p = 0.12), and all-cause mortality (14.1% vs 20.7%, HR 0.73, 95%CI 0.43-1.25;p = 0.26) were not significantly different in the two groups. The rate of rehospitalisation for coronary revascularisation was lower among the MINOCA patients (6.7% vs 27.7%; HR 0.27, 95% CI 0.15-0.47;p < 0.001).

CONCLUSIONS

MINOCA is frequent and not benign in patients with early-onset MI. Although there is a lower likelihood of CV death,the long-term risk of MACE and overall mortality is not significantly different from that of MICAD patients.

Coronary blood flow in heart failure: cause, consequence and bystander

Heart failure is a clinical syndrome where cardiac output is not sufficient to sustain adequate perfusion and normal bodily functions, initially during exercise and in more severe forms also at rest. The two most frequent forms are heart failure of ischemic origin and of non-ischemic origin. In heart failure of ischemic origin, reduced coronary blood flow is causal to cardiac contractile dysfunction, and this is true for stunned and hibernating myocardium, coronary microembolization, myocardial infarction and post-infarct remodeling, possibly also for the takotsubo syndrome. The most frequent form of non-ischemic heart failure is dilated cardiomyopathy, caused by genetic mutations, myocarditis, toxic agents or sustained tachyarrhythmias, where alterations in coronary blood flow result from and contribute to cardiac contractile dysfunction. Hypertrophic cardiomyopathy is caused by genetic mutations but can also result from increased pressure and volume overload (hypertension, valve disease). Heart failure with preserved ejection fraction is characterized by pronounced coronary microvascular dysfunction, the causal contribution of which is however not clear. The present review characterizes the alterations of coronary blood flow which are causes or consequences of heart failure in its different manifestations. Apart from any potentially accompanying coronary atherosclerosis, all heart failure entities share common features of impaired coronary blood flow, but to a different extent: enhanced extravascular compression, impaired nitric oxide-mediated, endothelium-dependent vasodilation and enhanced vasoconstriction to mediators of neurohumoral activation. Impaired coronary blood flow contributes to the progression of heart failure and is thus a valid target for established and novel treatment regimens.