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

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.

Emotional Stress Induced Broken Heart Syndrome: A Case Report

Takotsubo syndrome (TTS) is a medical condition mostly due to emotional or physical stress which frequently leads to misdiagnosis or late diagnosis. Patients tend to present initially with acute heart failure or acute coronary syndrome to our emergency department. Here we describe a patient with no history of cardiovascular disease, who developed TTS due to emotional stress from the death of her husband and then fully recovered during follow-up.

Importance of confirming the underlying diagnosis in patients with myocardial infarction and non-obstructive coronary arteries (MINOCA): a single-centre retrospective cohort study

BACKGROUND

Many patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) are discharged without a known aetiology for their clinical presentation. This study sought to assess the effect of this 'indeterminate MINOCA' diagnosis on the prevalence of recurrent cardiovascular events and presentations to the Cardiac Emergency Department (CED).

METHODS

We retrospectively analysed all patients meeting the diagnostic MINOCA criteria presenting at a large secondary hospital between January 2017 and April 2019.

PARTICIPANTS

Patients were divided into the (1) 'indeterminate MINOCA', or (2) 'MINOCA with diagnosis' group. The primary outcome was the occurrence of major adverse cardiac events (MACE) defined as the composite of all-cause mortality, non-fatal myocardial infarction, stroke and any revascularisation procedure. Secondary outcomes were all recurrent visits at the CED, and MACE including unplanned cardiac hospitalisation.

RESULTS

In 62/198 (31.3%) MINOCA patients, a conclusive diagnosis was found (myocardial infarction, (peri)myocarditis, cardiomyopathy, or miscellaneous). MINOCA patients with a confirmed diagnosis were younger compared to those with an indeterminate diagnosis (56.7 vs. 62.3 years, p = 0.007), had higher maximum troponin-T [238 ng/L vs. 69 ng/L, p < 0.001] and creatine kinase (CK) levels [212U/L vs. 152U/L, p = 0.007], and presented more frequently with electrocardiographic signs of ischaemia (71.0% vs. 47.1%, p = 0.002). Indeterminate MINOCA patients more often showed recurrent CED presentations (36.8% vs. 22.6%, p = 0.048), however the occurrence of cardiovascular events was equal (8.8 vs. 8.1%, p = 0.86). Multivariable analysis showed that elevated levels of troponin-T and CK, ST-segment deviation on electrocardiography, reduced left ventricular ejection fraction, regional wall motion abnormalities, and performance of additional examination methods were independent predictors for finding the underlying MINOCA cause.

CONCLUSIONS

Only in one-third of MINOCA patients a conclusive diagnosis for the acute presentation was identified. Recurrent CED visits were more often observed in the indeterminate MINOCA group, while the occurrence of cardiovascular events was similar across groups.

TRIAL REGISTRATION

Retrospectively registered.

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.