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Aim: To study clinical and demographic characteristics, treatment options, and clinical outcomes in patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) compared with patients with myocardial infarction with obstructive coronary arteries (MIOCA)., Material and Methods: This single-center prospective observational study included 712 successive patients diagnosed with acute myocardial infarction (MI), who routinely underwent direct coronary angiography. Based on the presence of stenosing coronary atherosclerosis, the patients were divided into two groups: MIOCA (coronary stenosis ≥50%) and MINOCA (coronary stenosis <50% without other, alternative causes). Clinical outcomes included in-hospital and long-term overall mortality, and cardiovascular rehospitalization. The median follow-up was 1.5 years., Results: MINOCA was diagnosed in 73 (10.3%) patients, 37 (50%) of whom were women. The median age of patients with MINOCA was 61 years and in the MIOCA group 65 years. No significant differences in cardiovascular risk factors were found between patients with MINOCA and MIOCA. In 53.4% of cases, the cause of MINOCA was a discrepancy between the myocardial oxygen demand and supply, and in 35.6% of cases, the cause was hypertensive crisis and pulmonary edema. The factors associated with MINOCA included an age ≤58 years, female gender, absence of the ST-segment elevation, absence of areas of impaired local contractility, and presence of aortic stenosis and bronchopulmonary infection. Patients with MINOCA were less likely to be prescribed acetylsalicylic acid, P2Y12 inhibitors, dual antiplatelet therapy, beta-blockers, and statins (p<0.05). Data on long-term outcomes were available for 87.5% of patients (n=623). The prognosis of patients with MIOCA was comparable for in-hospital mortality (1.5% vs. 6.2%; p=0.161) and long-term overall mortality (6.1% vs. 14.7%; p=0.059). Cardiovascular rehospitalizations were more frequent in the MINOCA group (33.3% vs. 21.5%; p=0.042)., Conclusion: The prevalence of MINOCA in our study was 10.3% among all patients with acute MI. MINOCA patients had comparable generally recognized cardiovascular risk factors with MIOCA patients. MINOCA patients had a comparable prognosis for in-hospital and long-term mortality and more often required cardiovascular rehospitalization.

Background: Despite the poor prognosis in patients with type 2 myocardial infarction (MI), no prospective data on risk stratification exists. The aim of this study was to develop and validate a model for prediction of 18-month mortality of among patients with type 2 MI (T2MI) and compare its performance with GRACE and TARRACO scores., Methods: The prospective observational study included 712 consecutive patients diagnosed with MI undergoing coronary angiography <24 h between January 2017 and December 2018. Diagnosis of T2MI was adjusted according to Third universal definition. A prognostic model was developed by using Bayesian approach and logistic regression analysis with identifying predictors for mortality. The model was validated by bootstrap validation. Comparison performance between scores using Delong test., Results: T2MI was identified in 174 (24.4%) patients. The median age of patients was 69 years, 52% were female. The mortality rate was 20.1% at 18 months. Prior MI, presence of ST elevation, hemoglobin level at admission, Charlson comorbidity index and were independently associated with 18-month mortality. The model to predict 18-month mortality showed excellent discrimination (optimism corrected c-statistic = 0.822) and calibration (corrected slope = 0.893). GRACE and TARRACO scores had moderate discrimination [c-statistic = 0.748 (95% CI 0.652-0.843) and 0.741, 95% CI 0.669-0.805), respectively] and inferior compared with model (p = 0.043 and 0.037, respectively)., Conclusions: The risk of mortality among T2MI patients could be accurately predicted by using common clinical characteristics and laboratory tests. Further studies are required with external validation of nomogram prior to clinical implementation., Competing Interests: Declaration of Competing Interest None., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Atherothrombosis is the principal mechanism of type 1 (T1) myocardial infarction (MI), while type 2 (T2) MI is typically diagnosed in the presence of triggers (anemia, arrhythmia, etc.). We aimed to evaluate the proportions of T1 vs. T2 MI based on angiographic and clinical definitions, their concordance and prognosis., Methods: Consecutive MI patients [n = 712, 61% male; age 64.6 ± 12.3 years] undergoing coronary angiography were classified according to the presence of atherothrombosis and identifiable triggers. Association of angiographic and clinical MI type criteria with adverse outcomes (Time follow-up was 1.5 years) was evaluated. Predictive ability of GRACE risk score for all-cause mortality was then assessed., Results: Atherothrombosis and clinical triggers were identified in 397 (55.6%) and 324 (45.5%) subjects, respectively. Only 247 (34.7%) patients had "true" T1MI (atherothrombosis+ / triggers-); 174 (24.4%) were diagnosed with "true" T2MI (atherothrombosis- / triggers+), while 291 (40.9%) had discordant clinical and angiographic characteristics. All-cause mortality in T2MI (20.1%) patients was higher than in T1MI (9.3%), P = 0.002. Presence of triggers [odds ratio (OR) 2.4, 95% CI 1.5-3.6, P < 0.0001] but not atherothrombosis [OR 0.8, 95% confidence interval (CI) 0.5-1.3, P = 0.26] was associated with worse prognosis. GRACE score is a better predictor of death in T1MI vs. T2MI: area under curve 0.893 (95% CI 0.830-0.956) vs 0.748 (95% CI 0.652-0.843), P = 0.013., Conclusion: Angiographic and clinical definitions of MI type are discordant in a substantial proportion of patients. Clinical triggers are associated with all-cause mortality. Predictive performance of GRACE score is worse in T2MI patients.

While atherosclerotic plaque disruption remains the hallmark of type 1 myocardial infarction (T1MI), multiple other mechanisms provoking myocardial supply/demand mismatch (eg, anemia and tachyarrhythmias) are recognized as the potential causes of type 2 myocardial infarction (T2MI). In clinical practice, angiography is underutilized in patients with MI that have typical T2MI triggers, although the presence of these triggers and various forms of atherosclerotic coronary artery disease is not mutually exclusive. We describe a 70-year-old man that developed MI during hospitalization for gastrointestinal bleeding. He was treated conservatively without angiography due to posthemorrhagic anemia, which is a recognized T2MI trigger, and subsequently developed refractory cardiogenic shock. Autopsy revealed atherothrombosis, which is characteristic of T1MI., (Copyright © 2020 Tehran University of Medical Sciences.)