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

Myocardial Infarction With Nonobstructive Coronary Arteries

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is the current term used to describe patients who have a myocardial infarction but have normal, non-obstructed coronary arteries on a coronary angiogram. There is still much debate over the definition, diagnosis, management and treatment of MINOCA. However, MINOCA is not a benign condition; prompt recognition and diagnosis can lead to better management and treatment and thus improve patient outcomes. This review article will update the most recent definition of MINOCA, discuss epidemiology and etiology, and review the diagnostic workup and management options for patients presenting with signs and symptoms of MINOCA.

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

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

Myocardial Infarction with Nonobstructive Coronary Arteries (MINOCA): A Review of the Current Position

Myocardial infarction with nonobstructive coronary arteries (MINOCA) remains a puzzling clinical entity that is characterized by clinical evidence of myocardial infarction (MI) with normal or near-normal coronary arteries on angiography (stenosis <50%). Major advances in understanding this condition have been made in recent years. The precise pathogenesis is poorly understood and is being studied and examined further. Guidelines indicate that MINOCA is a group of heterogeneous diseases with different mechanisms of pathology. Since there are multiple possible pathological mechanisms, it is not certain that the classical secondary prevention and treatment strategy for MI with obstructive coronary artery disease (MI-CAD) is optimal for MINOCA patients. The prognosis and predictors for MINOCA patients remain unclear. Although the prognosis is slightly better for MINOCA patients than for MI-CAD patients, MINOCA isn't always benign. The aim of this paper was to review the literature and evaluate MINOCA epidemiology, clinical features, etiology, diagnosis, treatment, and prognosis.

MINOCA: The caveat of absence of coronary obstruction in myocardial infarction

AIMS

Whether patients with MINOCA (myocardial infarction with non-obstructive coronary arteries) have better outcomes than patients with obstructive coronary artery disease remains contradictory. The current study focussed on the clinical profile and prognosis of MINOCA patients.

METHODS AND RESULTS

We performed a retrospective analysis of patients with acute coronary syndrome (ACS) admitted to the Isala hospital in Zwolle, the Netherlands, between 2006 and 2014. A total of 7693 patients were categorized into three groups: MINOCA, single-vessel obstructive ACS (SV-ACS), and multi-vessel obstructive ACS (MV-ACS). MINOCA patients (5.2% of the total population) were more likely to be female (51.5% vs. 30.3% and 26.0% in SV-ACS and MV-ACS, respectively, p < 0.001 for both). The prevalence of risk factors in the MINOCA group was in between the SV-ACS and MV-ACS groups. Logistic regression revealed a lower odds of dying in SV-ACS (odds ratio (OR) = 0.70 (p = 0.04)) and a similar odds in MV-ACS (OR = 0.88, p = 0.45) compared to MINOCA.

CONCLUSIONS

Patients with MINOCA show an 'intermediate' risk profile with mortality rates in between those of both ACS groups. Hence, MINOCA should be recognised as a potential risk factor for mortality, requiring adequate treatment and follow-up.

Clinical Outcomes and Predictors of ST-Elevation Versus Non-ST-Elevation Myocardial Infarction with Non-Obstructive Coronary Arteries

BACKGROUND

Myocardial infarction with nonobstructive coronary arteries (MINOCA) can be clinically categorized as ST-segment elevation (STE) and non-ST-segment elevation (NSTE), whose clinical prognosis are poorly understood. The aim of this study was to compare the clinical outcome and their predictors of patients with STE and NSTE in MINOCA population.

METHODS

A total of 265 patients with MINOCA (102 with STE, and 163 with NSTE) were consecutively collected. Clinical profile, prognosis, and predictors of all patients were assessed.

RESULTS

The proportion of patients with NSTE was greater than patients with STE in MINOCA population. Patients with NSTE were older and more likely to be female and had a higher incidence of atrial fibrillation. Both high density lipoprotein (HDL) and N-terminal pro-brain natriuretic peptide (NT-proBNP) were higher in the NSTE group. Patients with STE were more likely to have a history of smoking and a higher diastolic blood pressure. During the 1-year follow up, there were no differences in the outcomes between the STE and NSTE groups, with no significant differences in mortality and a similar rate of major adverse cardiovascular events (MACE) (20.9% vs 19.3%, P = 0.767). The multivariable predictors of MACE in the NSTE groups were age, lower level of total cholesterol, hypertension, and smoking history, whereas reduced left ventricular ejection fraction, and diabetes mellitus were the multivariable predictors of major adverse cardiac events in the STE group.

CONCLUSIONS

There were differences in the clinical profile between STE and NSTE in the MINOCA population, whereas the outcomes during the 1-year follow up were similar. The STE and NSTE groups had different predictive factors for major adverse cardiac events.

Early cardiac magnetic resonance imaging in troponin-positive acute chest pain and non-obstructed coronary arteries

OBJECTIVE

We assessed the diagnostic and prognostic implications of early cardiac magnetic resonance (CMR), CMR-based deformation imaging and conventional risk factors in patients with troponin-positive acute chest pain and non-obstructed coronary arteries.

METHODS

In total, 255 patients presenting between 2009 and 2019 with troponin-positive acute chest pain and non-obstructed coronary arteries who underwent CMR in ≤7 days were followed for a clinical endpoint of all-cause mortality. Cine movies, T2-weighted and late gadolinium-enhanced images were evaluated to establish a diagnosis of the underlying heart disease. Further CMR analysis, including left ventricular strain, was carried out.

RESULTS

CMR (performed at a mean of 2.7 days) provided the diagnosis in 86% of patients (54% myocarditis, 22% myocardial infarction (MI) and 10% Takotsubo syndrome and myocardial contusion (n=1)). The 4-year mortality for a diagnosis of MI, myocarditis, Takotsubo and normal CMR patients was 10.2%, 1.6%, 27.3% and 0%, respectively. We found a strong association between CMR diagnosis and mortality (log-rank: 24, p<0.0001). Takotsubo and MI as the diagnosis, age, hypertension, diabetes, female sex, ejection fraction, stroke volume index and most of the investigated strain parameters were univariate predictors of mortality; however, in the multivariate analysis, only hypertension and circumferential mechanical dispersion measured by strain analysis were independent predictors of mortality.

CONCLUSIONS

CMR performed in the early phase establishes the proper diagnosis in patients with troponin-positive acute chest pain and non-obstructed coronary arteries and provides additional prognostic factors. This may indicate that CMR could play an additional role in risk stratification in this patient population.

Clinical presentation and 3-year outcomes of patients with acute coronary syndromes and non-obstructive coronary arteries on angiography

Background

With the emerging interest in patients with myocardial infarction with non-obstructive coronary arteries (MINOCA), there is a need to define an even broader group of patients with the syndrome of myocardial ischemia with non-obstructive coronary arteries (INOCA). There are limited data on the clinical characteristics and prognoses of such patients who present with symptoms of acute coronary syndrome (ACS) and undergo urgent coronary angiography that reveals no significant lesions. The aim of this observational study was to compare patients with ACS INOCA and those with ACS with obstructive coronary artery disease (OCAD) both within unadjusted cohorts and with propensity score matched controls.

Methods and results

This observational study was based on the data from the Polish National Registry of Invasive Cardiology Procedures. Of 9744 patients included, 7624 had OCAD and 2120 had ACS INOCA. In unadjusted cohorts, the overall survival and incidence of major adverse cardiovascular events (MACE: death, cardiac arrest, myocardial infarction, stroke, and heart failure hospitalization) until 36 months were higher in patients with ACS OCAD. Following propensity matching, higher win ratios of death (p = 0.02), additional revascularizations by percutaneous coronary intervention or coronary artery bypass graft surgery (p<0.001), and cardiac hospitalization (p<0.001) were observed in these patients. In contrast, the win ratios of myocardial infarction (p = 0.74), heart failure hospitalization (p = 0.86), and MACE (p = 0.07) were not significantly different between the groups.

Conclusions

The prognosis of patients with ACS INOCA was more favorable than that of patients with ACS OCAD; however, the differences diminished after adjustments for the initial clinical profiles. An ACS incident should not be judged as trivial even when cardiac markers remain stable and no significant lesions are found on angiography.

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

BACKGROUND

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Endothelin: 30 Years From Discovery to Therapy

Discovered in 1987 as a potent endothelial cell-derived vasoconstrictor peptide, endothelin-1 (ET-1), the predominant member of the endothelin peptide family, is now recognized as a multifunctional peptide with cytokine-like activity contributing to almost all aspects of physiology and cell function. More than 30 000 scientific articles on endothelin were published over the past 3 decades, leading to the development and subsequent regulatory approval of a new class of therapeutics-the endothelin receptor antagonists (ERAs). This article reviews the history of the discovery of endothelin and its role in genetics, physiology, and disease. Here, we summarize the main clinical trials using ERAs and discuss the role of endothelin in cardiovascular diseases such as arterial hypertension, preecclampsia, coronary atherosclerosis, myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) caused by spontaneous coronary artery dissection (SCAD), Takotsubo syndrome, and heart failure. We also discuss how endothelins contributes to diabetic kidney disease and focal segmental glomerulosclerosis, pulmonary arterial hypertension, as well as cancer, immune disorders, and allograft rejection (which all involve ET_A autoantibodies), and neurological diseases. The application of ERAs, dual endothelin receptor/angiotensin receptor antagonists (DARAs), selective ET_B agonists, novel biologics such as receptor-targeting antibodies, or immunization against ET_A receptors holds the potential to slow the progression or even reverse chronic noncommunicable diseases. Future clinical studies will show whether targeting endothelin receptors can prevent or reduce disability from disease and improve clinical outcome, quality of life, and survival in patients.

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

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

Myocardial Infarction With Nonobstructive Coronary Arteries: A Call for Individualized Treatment

See Article Choo et al.