Clinical Characteristics, Treatments, and Outcomes of Patients with Myocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA): Results from a Multicenter National Registry

Intravascular imaging in the diagnosis and management of patients with suspected intracoronary pathologies: A CJC White Paper

Intravascular imaging has become an integral part of the diagnostic and management strategies for intracoronary pathologies. This White Paper summarizes current evidence and its implications on the use of intravascular imaging in interventional cardiology practice. The areas addressed are planning and optimization of percutaneous coronary intervention, management of stent failure, and evaluation of ambiguous coronary lesions and myocardial infarction with non-obstructive coronary disease (MINOCA). Findings are presented following the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system in an expert consensus process involving a diverse Writing group and vetted by a Review group. Expert consensus was achieved around nine statements. Use of intravascular imaging in guiding percutaneous revascularization is supported by high quality evidence, particularly for lesions with increased risk of recurrent events or stent failure. Specific considerations for intravascular imaging guidance of intervention in left main lesions, chronic occlusion lesions as well as patients at high risk of contrast nephropathy are explored. Use of intravascular imaging to identify pathologies associated with stent failure and guide repeat intervention, resolve ambiguities in lesion assessment and establish diagnoses in patients presenting with MINOCA is supported by moderate to low quality evidence. Each topic is accompanied by clinical pointers to aid the practicing interventional cardiologist in implementation of the White paper findings. The findings of this White Paper will help to guide the utilization of intravascular imaging towards those situations in which the balance of efficacy, safety and cost are most optimal.

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.

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.

Long term all-cause mortality after myocardial infarction with non-obstructed vs obstructed coronary artery disease: a meta-analysis of adjusted data

BACKGROUND

The difference in the long-term outcomes of myocardial infarction in patients with non-obstructed coronary arteries (MINOCA) and patients with myocardial infarction with obstructed coronary artery disease (MI-CAD) is not clear. The current study aimed to pool adjusted data to compare long-term outcomes of MINOCA vs MI-CAD.

METHODS

Electronic literature search of PubMed, Embase, CENTRAL, and Google Scholar databases was done for publications up to 18th June 2023. Only studies reporting multivariable-adjusted data with > 1 year of follow-up were included.

RESULTS

Sixteen studies met the inclusion criteria. Our meta-analysis revealed no statistically significant difference in the risk of all-cause mortality between MINOCA and MI-CAD patients (HR: 0.90 95% CI 0.68, 1.19 I2 = 94% p = 0.48). Analysis of the limited data showed a reduced combined risk of all-cause mortality and MI (HR: 0.54 95% CI 0.39, 0.76 I2 = 72% p = 0.003) and major adverse cardiac events (MACE) (HR: 0.66 95% CI 0.51, 0.84 I2 = 51% p = 0.0009) in patients with MINOCA vs MI-CAD, and no difference in the risk of cardiovascular mortality (HR: 0.81 95% CI 0.54, 1.22 I2 = 0% p = 0.31) and readmission between the two groups (HR: 0.85 95% CI 0.61, 1.19 I2 = 90% p = 0.35).

CONCLUSION

A pooled analysis of adjusted outcomes from the available studies indicated that MINOCA and MI-CAD patients have similar long-term all-cause mortality risk. Our conclusions on the risk of cardiovascular mortality, MACE and readmission rates need to be taken with caution due to a lack of adequate studies. Further research is needed to strengthen the evidence on this important subject.

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.

Comparison of Long-Term Outcomes of Patients With Myocardia Infarction (MI) With Non-obstructive Coronary Arteries and MI With Obstructive Coronary Arteries: A Systematic Review and Meta-Analysis

The aim of this study was to compare long-term outcomes in patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) and patients with myocardial infarction with obstructive coronary arteries (MIOCA). This meta-analysis was conducted according to the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The literature search was conducted in online databases including PubMed and Web of Science from 2010 onwards. Primary outcomes assessed in this meta-analysis included major adverse cardiovascular events (MACE) and all-cause mortality. Secondary outcomes included cardiovascular mortality and myocardial infarction. A total of 16 studies were included in the meta-analysis. Pooled analysis showed that the risk of MACE was higher in MIOCA patients (risk ratio (RR): 1.47, 95%CI: 1.43-1.52, p-value: 0.001) compared to MINOCA patients. Additionally, the risk of all-cause mortality was also significantly higher in MIOCA patients compared to MINOCA (RR: 1.33, 95%CI: 1.14-1.56, p-value: 0.001). Our findings also indicate that patients with MIOCA are at a significantly higher risk of recurrent myocardial infarction and cardiovascular-related mortality compared to patients with MINOCA. Overall, the insights gained from this meta-analysis have significant clinical implications, guiding decision-making in the management of patients with MINOCA.

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.

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

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

Association of stress hyperglycemia ratio and poor long-term prognosis in patients with myocardial infarction with non-obstructive coronary arteries

BACKGROUND

Stress hyperglycemia ratio (SHR) is a novel biomarker of true acute hyperglycemia condition and is associated with a worse prognosis in patients with myocardial infarction (MI). However, the effects of SHR in the setting of MI with non-obstructive coronary arteries (MINOCA) have not been investigated. This study aimed to explore the association between SHR and long-term clinical outcomes among MINOCA patients.

METHODS

A total of 410 MINOCA patients were included in the final analysis of this study. The patients were divided into three groups based on the SHR tertiles: [SHR1 group (SHR ≤ 0.73), (n = 143); SHR2 group (SHR 0.73-0.84), n = 131; and SHR3 group (SHR ≥ 0.84), n = 136]. Follow-up for major adverse cardiovascular events (MACE) was conducted on all patients. Cox regression and Kaplan-Meier curve analysis were used to evaluate the relationship between SHR and MACE. The receiver operating curve (ROC) analysis was applied to obtain the optimal cut-off value of SHR for predicting clinical MACE.

RESULTS

A total of 92 patients developed MACE during the mean 34 months of follow-up. A significant increase in MACE was observed in the SHR3 group compared to the SHR1 and SHR2 groups (35.3% vs. 15.4% and 16.8%, respectively; P < 0.001). The Kaplan-Meier curves demonstrate that SHR3 patients had the highest MACE risk compared to SHR1 and SHR2 patients (log-rank P < 0.001). In addition, when both SHR tertiles and diabetes status were considered, those with SHR3 and diabetes had the highest hazard of MACE (log-rank P < 0.001). Multivariate Cox regression analysis showed that the SHR3 is associated with a 2.465-fold increase in the risk of MACE (adjusted HR, 2.465; 95% CI 1.461-4.159, P = 0.001). The ROC curve analysis showed that the optimal SHR cut-off value for predicting clinical MACE among MINOCA was 0.86.

CONCLUSION

Our data indicates, for the first time, that SHR is independently associated with poor long-term prognosis in patients suffering from MINOCA. The optimal SHR cut-off value for predicting clinical MACE among MINOCA patients was 0.86. These findings suggest that SHR may play a potential role in the cardiovascular risk stratification of the MINOCA population.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

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.

Statin Use in Cancer Patients with Acute Myocardial Infarction and Its Impact on Long-Term Mortality

Statin use and its impact on long-term clinical outcomes in active cancer patients following acute myocardial infarction (MI) remains insufficiently elucidated. Of the 1011 consecutive acute MI patients treated invasively between 2012 and 2017, cancer was identified in 134 (13.3%) subjects. All patients were observed within a median follow-up of 69.2 (37.8−79.9) months. On discharge, statins were prescribed less frequently in MI patients with cancer as compared to the non-cancer MI population (79.9% vs. 91.4%, p < 0.001). The most common statin in both groups was atorvastatin. The long-term mortality was higher in MI patients not treated vs. those treated with statins, both in non-cancer (29.5%/year vs. 6.7%/year, p < 0.001) and cancer groups (53.9%/year vs. 24.9%/year, p < 0.05), respectively. Patient’s age (hazard ratio (HR) 1.04, 95% confidence interval (CI) 1.03−1.05, p < 0.001, per year), an active cancer (HR 2.42, 95% CI 1.89−3.11, p < 0.001), hemoglobin level (HR 1.14, 95% CI 1.09−1.20, p < 0.001, per 1 g/dL decrease), and no statin on discharge (HR 2.13, 95% CI 1.61−2.78, p < 0.001) independently increased long-term mortality. In MI patients, simultaneous diagnosis of an active cancer was associated with less frequently prescribed statins on discharge. Irrespective of cancer diagnosis, no statin use was found as an independent predictor of increased long-term mortality.

Metabolic syndrome and the risk of adverse cardiovascular events in patients with myocardial infarction with non-obstructive coronary arteries

BACKGROUND AND AIMS

Metabolic syndrome (MeS) is recognized as a significant predictor of poor outcomes in coronary artery disease. However, its prognostic implications in myocardial infarction with non-obstructive coronary arteries (MINOCA) have not been examined. We aimed at investigating the role of MeS on the clinical outcomes in MINOCA patients.

METHODS AND RESULTS

Patients diagnosed with MINOCA between 2015 and 2019 were included. MeS was defined according to modified NCEP-ATPIII criteria. The primary endpoint was major adverse cardiovascular events (MACE). Cox regression analysis was used to evaluate the correlation between MeS and the hazard of MACE. The integrated discrimination improvement (IDI) and net reclassification index (NRI) were performed to assess MeS incremental predictive value. Of 281 MINOCA patients, 83 (29.5%) patients satisfied the MeS criteria. During a median follow-up duration of 28 months, MINOCA patients with MeS had a notably higher rate of MACE than those without MeS (30.1% vs. 17.6%, respectively P = 0.020). Cox regression analysis revealed that MeS was associated with an increased hazard of MACE (adjusted HR 2.126; 95% CI: 1.193-3.787, P = 0.010). When each component of MeS was analyzed as a categorized variable separately, only high fasting blood glucose and BMI ≥25 kg/m² were associated with an increased hazard of MACE. Moreover, MeS had an incremental predictive ability for MACE when added to a model with clinical risk factors.

CONCLUSION

MeS is relatively common in patients with MINOCA. The presence of MeS significantly increased the hazard of MACE among the MINOCA population.

Diagnostic value of Cardiac Magnetic Resonance Imaging and Intracoronary Optical Coherence Tomography in patients with a working diagnosis of Myocardial Infarction with Non-obstructive Coronary Arteries - A Systematic review and Meta-analysis

BACKGROUND

We aimed to study the efficacy of cardiac magnetic resonance imaging (CMR) and intracoronary optical coherence tomography (OCT) in detecting the etiology of myocardial infarction with non-obstructive coronary arteries (MINOCA).

METHODS

A systematic search was conducted in PubMed, Medline, and Cochrane databases. Search terms used: Myocardial infarction, Coronary angiography, Normal coronary arteries, CMR, and OCT. Inclusion criteria was fulfilled by 18 studies. Meta-analysis was performed with 15 studies.

RESULTS

A total of 2697 patients were included. The mean age of all the patients was 51.5 and 56.4% were men. CMR established diagnosis in 74% of the patients; 29% had acute myocarditis, 18% had true myocardial infarction and 12% had takotsubo cardiomyopathy. Combining OCT with CMR was better at finding the etiology than either modality individually.

CONCLUSION

CMR is integral in identifying the etiology of MINOCA. Coupling OCT and CMR is better than either technique individually at finding the cause.

Association between Initial Serum Total Bilirubin and Clinical Outcome in Myocardial Infarction with Non-Obstructive Coronary Arteries

Background: Liver function parameters, particularly serum total bilirubin (TB), are closely associated with cardiovascular diseases. However, the impact of serum TB among patients with myocardial infarction and non-obstructive coronary (MINOCA) remains unknown. Our study investigated the relationship between serum TB at admission and long-term adverse clinical outcomes in MINOCA patients. Methods: A total of 273 consecutive MINOCA patients were categorized into low and high serum TB groups based on the optimal cut-off of 0.9 mg/dl. The primary endpoint was major adverse cardiovascular events (MACE), including cardiac death, non-fatal MI, heart failure, and angina rehospitalization. Receiver-operating characteristic, Cox regression, and Kaplan-Meier analyses were used to evaluate the association of high serum TB with cardiovascular outcomes. Results: High serum TB was found in 68 (24.9%) patients. The incidence of MACE was higher in the high TB group than in the low TB group after a median follow-up of 28 months (30.9 vs. 17.1%, P=0.015). The Kaplan-Meier curve analysis also indicated that patients in the high TB group had a higher risk of developing MACE (log-rank P=0.023). Cox regression analysis showed that high serum TB (>0.9mg/dl) significantly correlated with increased MACE risk (HR=1.90, 95%CI: 1.12-3.22, P=0.018). After adjusting for numerous clinical variables, the high serum TB remained significantly associated with an increased risk of MACE (HR=2.04, 95%CI: 1.05-3.94, P=0.034). Conclusion: High initial serum TB (>0.9mg/dl) is a robust predictor of poor clinical outcomes among MINOCA patients. In clinical settings, assessing serum TB at admission may help identify high-risk patients presenting with MINOCA.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

OCT Findings in MINOCA

Myocardial infarction with non-obstructive coronary artery disease (MINOCA) is a working diagnosis for patients presenting with acute myocardial infarction without obstructive coronary artery disease on coronary angiography. It is a heterogenous entity with a number of possible etiologies that can be determined through the use of appropriate diagnostic algorithms. Common causes of a MINOCA may include plaque disruption, spontaneous coronary artery dissection, coronary artery spasm, and coronary thromboembolism. Optical coherence tomography (OCT) is an intravascular imaging modality which allows the differentiation of coronary tissue morphological characteristics including the identification of thin cap fibroatheroma and the differentiation between plaque rupture or erosion, due to its high resolution. In this narrative review we will discuss the role of OCT in patients presenting with MINOCA. In this group of patients OCT has been shown to reveal abnormal findings in almost half of the cases. Moreover, combining OCT with cardiac magnetic resonance (CMR) was shown to allow the identification of most of the underlying mechanisms of MINOCA. Hence, it is recommended that both OCT and CMR can be used in patients with a working diagnosis of MINOCA. Well-designed prospective studies are needed in order to gain a better understanding of this condition and to provide optimal management while reducing morbidity and mortality in that subset patients.

Myocardial Infarction with Nonobstructive Coronary Arteries: A Diagnostic Challenge

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is a significant cause of cardiovascular morbidity, especially among non-white women younger than 55 years. It is a working diagnosis that warrants further investigation due to its varied underlying pathophysiologic mechanisms. Investigations may be hampered by unavailability of testing modalities, cost, and the expertise to carry out the tests, as they are highly specialized. Clinical history is therefore important, especially in developing countries, to predict potential causes and institute empirical treatment without the luxury of tests. Some physicians are also unaware of this phenomenon and may dismiss symptoms as functional when a coronary angiogram shows nonobstructed coronary arteries, potentially resulting in patients suffering symptoms for longer and incurring extra cost. Most importantly, it leaves them at risk of major adverse cardiovascular events. This article presents a patient with atrial fibrillation who was diagnosed with MINOCA and highlights the diagnostic challenges in evaluating MINOCA.

Myocardial Infarction with Nonobstructive Coronary Artery Disease—Definition, Etiopathogenesis, Diagnosis, and Management

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is a complex clinical syndrome that is characterized by evidence of acute myocardial infarction in the absence of significant epicardial coronary artery disease on angiography. The term “MINOCA” encompasses a group of heterogeneous diseases with varying underlying mechanisms and each with its own pathophysiology. Overlooked plaque rupture or erosion and coronary vasospasm are the most common causes of MINOCA and can be diagnosed by routine intracoronary imaging and vasoreactivity testing, respectively. Coronary microvascular dysfunction is a less recognized, albeit an important cause of morbidity in patients presenting with MINOCA. Although MINOCA is a rare presentation of acute coronary syndrome, it is not a benign disorder and can have adverse consequences if untreated. In this article, we aim to review the pathogenesis, clinical characteristics, and finally propose a systematic approach in the diagnosis and management of patients with MINOCA.