How to Use Cardiac Magnetic Resonance Imaging in Myocardial Infarction With Nonobstructive Coronary Arteries.

The working diagnosis Myocardial Infarction with Nonobstructive Coronary Arteries (MINOCA) is being increasingly recognized with the common use of high-sensitivity troponins and coronary angiography, accounting for 5% to 10% of all acute myocardial infarction presentations. Cardiac magnetic resonance (CMR) imaging is pivotal in patients presenting with suspected MINOCA, mainly to delineate those with a nonischemic cause, for example, myocarditis and Takotsubo syndrome, from those with true ischemic myocardial infarction, that is, MINOCA. The optimal timing for CMR imaging in patients with suspected MINOCA has been uncertain and, until recently, not been examined prospectively. Previous retrospective studies have indicated that the diagnostic yield decreases with time from the acute event. The SMINC studies (Stockholm Myocardial Infarction with Normal Coronaries) show that CMR should be performed early in all patients with the working diagnosis of MINOCA, with the possible exception of patients who are clearly identified as having Takotsubo syndrome as determined by echocardiography. In addition to CMR imaging, other investigations of importance in selected patients may be pulmonary artery computed tomography to exclude pulmonary embolism, optical coherence tomography to identify plaque disruption, and acetylcholine provocation to identify coronary artery spasm. Imaging of patients with the working diagnosis MINOCA, which is centered on CMR together with supplemental investigations, results in a clear diagnosis in approximately three-quarters of the patients. This is a good example of personalized medicine, because a correct diagnosis will not only increase the satisfaction of the individual patient but also result in optimizing treatment without harming the patient.

Early versus late cardiac magnetic resonance in the diagnosis of myocardial infarction with non-obstructive coronary arteries.

INTRODUCTION AND OBJECTIVES: Myocardial infarction with non-obstructive coronary arteries (MINOCA) is responsible for about 10% of all acute myocardial infarctions (AMI). Therapeutic strategies and prognosis depend on the underlying etiology, and a multimodal approach is essential. The objectives of this study were to characterize the group of patients diagnosed with MINOCA and to valuate the diagnostic yield of cardiovascular magnetic resonance (CMR). METHODS: This was a retrospective, observational, and analytical study, including 516 patients admitted for a non-ST-elevation MI and with no significant coronary disease on coronary angiography between January 2016 and September 2021. RESULTS: After the inclusion criteria, 163 patients remained of the 516 admitted to the study. They were divided into four groups based on the CMR results: MINOCA (n=51), Takotsubo syndrome (n=37), myocarditis (n=33), and without diagnosis (n=42). Most patients diagnosed with MINOCA were female with a mean age of 61.06±13.83 years. CMR identified the diagnosis in 74.2% of patients admitted for suspected acute MI, in which coronary angiography showed the absence of significant obstructions. The median time between hospital admission and CMR was significantly shorter in the groups that had a diagnosis compared with the group with no diagnosis (p=0.038), with a significant increase in diagnostic profitability if CMR was performed up to 14 days after admission (p=0.022). There were no deaths of cardiovascular etiology during the follow-up period. CONCLUSIONS: CMR was fundamental as it identified the diagnosis in three out of four patients; it should be performed in the first 14 days.

Diagnostic and Prognostic Role of Cardiac Magnetic Resonance in MINOCA: Systematic Review and Meta-Analysis.

BACKGROUND: Myocardial infarction with nonobstructive coronary arteries (MINOCA) is common in current clinical practice. Cardiac magnetic resonance (CMR) plays an important role in its management and is increasingly recommended by all the current guidelines. However, the prognostic value of CMR in patients with MINOCA is still undetermined. OBJECTIVES: The purpose of this study was to determine the diagnostic and prognostic value of CMR in the management of patients with MINOCA. METHODS: A systematic review was performed to identify studies reporting the results of CMR findings in patients with MINOCA. Random effects models were used to determine the prevalence of different disease entities: myocarditis, myocardial infarction (MI), or takotsubo syndrome. Pooled odds ratios (ORs) and 95% CIs were calculated to evaluate the prognostic value of CMR diagnosis in the subgroup of studies that reported clinical outcomes. RESULTS: A total of 26 studies comprising 3,624 patients were included. The mean age was 54.2 ± 5.3 years, and 56% were men. MINOCA was confirmed in only 22% (95% CI: 0.17-0.26) of the cases and 68% of patients with initial MINOCA were reclassified after the CMR assessment. The pooled prevalence of myocarditis was 31% (95% CI: 0.25-0.39), and takotsubo syndrome 10% (95% CI: 0.06-0.12). In a subgroup analysis of 5 studies (770 patients) that reported clinical outcomes, CMR diagnosis of confirmed MI was associated with an increased risk of major adverse cardiovascular events (pooled OR: 2.40; 95% CI: 1.60-3.59). CONCLUSIONS: In patients with MINOCA, CMR has been demonstrated to add an important diagnostic and prognostic value, proving to be crucial for the diagnosis of this condition. Sixty-eight percent of patients with initial MINOCA were reclassified after the CMR evaluation. CMR-confirmed diagnosis of MINOCA was associated with an increased risk of major adverse cardiovascular events at follow-up.

Nilotinib related acute myocardial infarction with nonobstructive coronary arteries: a case report and literature review.

BACKGROUND: Myocardial Ischemia with No Obstructive Coronary Artery Disease (MINOCA) is a common cause of type 2 acute myocardial infarction (AMI) which requires careful differential diagnosis. Coronary artery spasm (CAS) syndrome is one etiology that can lead to MINOCA. Nilotinib, a targeted treatment for chronic myeloid leukemia (CML), has been reported to be related with increased risk of adverse vascular events. CASE PRESENTATION: A 67-year-old male patient was admitted to hospital with acute chest pain. He had a past medical history of CML and a history of treatment with nilotinib for 12 months. Coronary angiography (CAG) showed no significant stenosis. Since the onset of angina was generally in the early morning, and ECG and echocardiography suggested right coronary artery (RCA) disease, an ergonovine provocation test was performed to confirm the diagnosis of CAS. After intracoronary administration of ergonovine, middle and distal RCA showed over 90% vasoconstriction. Nilotinib related MINOCA, CAS and CML were diagnosed. Lifestyle changes (cessation of smoking), anti-spasmodics, statin treatment and adjustment of the nilotinib dose (from 200 mg bid, to 150 mg bid) were recommended for this patient. Six-month's follow-up showed good recovery with no onsets of angina. CONCLUSIONS: Physicians should be vigilant to adverse vascular events when treating patients who have been prescribed nilotinib. It is suggested that in patients with MINOCA who have a history of treatment with nilotinib, CAS-induced MINOCA should be included in the differential diagnosis. Further studies are needed to clarify the mechanism and to find better management.

The evolving role of cardiac imaging in patients with myocardial infarction and non-obstructive coronary arteries.

Myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA) represents a heterogeneous clinical conundrum accounting for about 6%-8% of all acute MI who are referred for coronary angiography. Current guidelines and consensus documents recommend that these patients are appropriately diagnosed, uncovering the causes of MINOCA, so that specific therapies can be prescribed. Indeed, there are a variety of causes that can result in this clinical condition, and for this reason diagnostic cardiac imaging has an emerging critical role in the assessment of patients with suspected or confirmed MINOCA. In last years, different cardiac imaging techniques have been evaluated in this context, and the comprehension of their strengths and limitations is of the utmost importance for their effective use in clinical practice. Moreover, recent evidence is clearly suggesting that a multimodality cardiac imaging approach, combining different techniques, seems to be crucial for a proper management of MINOCA. However, great variability still exists in clinical practice in the management of patients with suspected MINOCA, also depending on the availability of diagnostic tools and local expertise. Herein, we review the current knowledge supporting the use of different cardiac imaging techniques in patients with MINOCA, underscoring the importance of a comprehensive multimodality cardiac imaging approach and proposing a practical diagnostic algorithm to properly identify and treat the specific causes of MINOCA, in order to improve prognosis and the quality of life in these patients.

Impact of admission hyperglycemia on short and long-term prognosis in acute myocardial infarction: MINOCA versus MIOCA.

BACKGROUND: The prognostic role of hyperglycemia in patients with myocardial infarction and obstructive coronary arteries (MIOCA) is acknowledged, while data on non-obstructive coronary arteries (MINOCA) are still lacking. Recently, we demonstrated that admission stress-hyperglycemia (aHGL) was associated with a larger infarct size and inflammatory response in MIOCA, while no differences were observed in MINOCA. We aim to investigate the impact of aHGL on short and long-term outcomes in MIOCA and MINOCA patients. METHODS: Multicenter, population-based, cohort study of the prospective registry, designed to evaluate the prognostic information of patients admitted with acute myocardial infarction to S. Orsola-Malpighi and Maggiore Hospitals of Bologna metropolitan area. Among 2704 patients enrolled from 2016 to 2020, 2431 patients were classified according to the presence of aHGL (defined as admission glucose level ≥ 140 mg/dL) and AMI phenotype (MIOCA/MINOCA): no-aHGL (n = 1321), aHGL (n = 877) in MIOCA and no-aHGL (n = 195), aHGL (n = 38) in MINOCA. Short-term outcomes included in-hospital death and arrhythmias. Long-term outcomes were all-cause and cardiovascular mortality. RESULTS: aHGL was associated with a higher in-hospital arrhythmic burden in MINOCA and MIOCA, with increased in-hospital mortality only in MIOCA. After adjusting for age, gender, hypertension, Killip class and AMI phenotypes, aHGL predicted higher in-hospital mortality in non-diabetic (HR = 4.2; 95% CI 1.9-9.5, p = 0.001) and diabetic patients (HR = 3.5, 95% CI 1.5-8.2, p = 0.003). During long-term follow-up, aHGL was associated with 2-fold increased mortality in MIOCA and a 4-fold increase in MINOCA (p = 0.032 and p = 0.016). Kaplan Meier 3-year survival of non-hyperglycemic patients was greater than in aHGL patients for both groups. No differences in survival were found between hyperglycemic MIOCA and MINOCA patients. After adjusting for age, gender, hypertension, smoking, LVEF, STEMI/NSTEMI and AMI phenotypes (MIOCA/MINOCA), aHGL predicted higher long-term mortality. CONCLUSIONS: aHGL was identified as a strong predictor of adverse short- and long-term outcomes in both MIOCA and MINOCA, regardless of diabetes. aHGL should be considered a high-risk prognostic marker in all AMI patients, independently of the underlying coronary anatomy. Trial registration data were part of the ongoing observational study AMIPE: Acute Myocardial Infarction, Prognostic and Therapeutic Evaluation. ClinicalTrials.gov Identifier: NCT03883711.

Myocardial infarct size and sex-related angiographic differences in myocardial infarction in nonobstructive coronary artery disease.

BACKGROUND: Myocardial infarction in nonobstructive coronary artery disease (MINOCA) is a recently described infarct subtype. There are few studies that examine coronary artery disease (CAD) extent, MI size and type, and treatment differences at hospital discharge compared to myocardial infarction in obstructive coronary artery disease (MICAD), or that explore sex-specific MINOCA attributes of coronary anatomy and infarct size. METHODS: Our study population consisted of a single tertiary-center of consecutive patients that had coronary angiography for acute MI between 2005 and 2015. The MI type at presentation, MI size and ejection fraction (post-MI), and gender differences between MINOCA patients were examined. RESULT: Among 1698 cases with acute MI, 95 had MINOCA (5.6%). MINOCA patients were younger, more often had NSTEMI, lower peak cardiac troponin (cTn) values, and greater ejection fraction than MICAD patients (all P-values <0.005). At hospital discharge, 30-day re-admission rates were similar. MINOCA patients less frequently received optimal medical therapy. When women were analyzed, the 45 women with MINOCA had smaller MIs (P < 0.001) and greater ejection fraction (P = 0.002) than the 358 women with MICAD. Sex comparisons of the 95 MINOCA patients revealed women were older than men (P < 0.001), had lower mean peak cTn values (P < 0.001), greater ejection fraction (P = 0.02), and more single-vessel disease involvement than men (P < 0.0001). CONCLUSION: The average MI size is smaller in MINOCA than MICAD patients, and there are sex-related differences in clinical presentation, coronary artery disease extent, and MI size. Re-admission rates are similar and MINOCA patients are less likely to receive guideline recommended medical therapy at discharge.