CMR reclassifies the majority of patients with suspected MINOCA and non MINOCA.

AIMS: In ∼5-15% of all cases of acute coronary syndromes (ACS) have unobstructed coronaries on angiography. Cardiac magnetic resonance (CMR) has proven useful to identify in most patients the underlying diagnosis associated with this presentation. However, the role of CMR to reclassify patients from the initial suspected condition has not been clarified. The aim of this study was to assess the proportion of patients with suspected MINOCA, or non-MINOCA, that CMR reclassifies with an alternative diagnosis from the original clinical suspicion. METHODS AND RESULTS: A retrospective cohort of patients in a tertiary cardiology centre was identified from a registry database. Patients who were referred for CMR for investigation of suspected MINOCA, and a diagnosis pre- and post-CMR was recorded to determine the proportion of diagnoses reclassified. A total of 888 patients were identified in the registry. CMR reclassified diagnosis in 78% of patients. Diagnosis of MINOCA was confirmed in only 243 patients (27%), whilst most patients had an alternative diagnosis (73%): myocarditis n = 217 (24%), Takotsubo syndrome n = 115 (13%), cardiomyopathies n = 97 (11%), and normal CMR/non-specific n = 216 (24%). CONCLUSION: In a large single-centre cohort of patients presenting with ACS and unobstructed coronary arteries, most patients had a non-MINOCA diagnosis (73%) (myocarditis, Takotsubo, cardiomyopathies, or normal CMR/non-specific findings), whilst only a minority had confirmed MINOCA (27%). Performing CMR led to reclassifying patients' diagnosis in 78% of cases, thus confirming its important clinical role and underscoring the clinical challenge in diagnosing MINOCA and non MINOCA conditions.

Sex differences in patients with acute coronary syndromes and non-obstructive coronary arteries: Presentation and outcome.

BACKGROUND: A substantial number of patients present with a suspected ACS and non-obstructive coronary arteries; sex differences in these patients are not well understood. This study aims to evaluate the impact of sex on clinical presentation and outcome in patients with suspected acute coronary syndrome (ACS) and non-obstructive coronary arteries with a final diagnosis confirmed by cardiovascular magnetic resonance imaging (CMR). METHODS: Consecutive patients with ACS and non-obstructive coronary arteries (n = 719) with an unclear cause from a single tertiary centre who were referred for CMR were included. The primary endpoint was all-cause mortality. RESULTS: CMR was performed at a median time of 30 days after presentation and identified a diagnosis in 74% of patients. All-cause mortality was 9.5% over a median follow up of 4.9 years, with no significant difference between sexes (8.8% versus 10.1%; p = 0.456). Men were more likely to have non-ischaemic aetiology on CMR than women (55% v 41%, p < 0.001), but were equally likely to have an ischaemic cause (25% v 27%, p = 0.462). Age group (HR 1.58, p < 0.001) and LV ejection fraction (HR 0.98, p = 0.023) were independent predictors of mortality. CONCLUSIONS: There is no difference in all-cause mortality between sexes in patients presenting with suspected ACS and non-obstructive coronary arteries.

Peak Troponin and CMR to Guide Management in Suspected ACS and Nonobstructive Coronary Arteries.

BACKGROUND: Patients presenting with acute coronary syndrome (ACS) and nonobstructive coronary arteries are a diagnostic dilemma. Cardiac magnetic resonance (CMR) has an overall diagnostic yield of ∼75%; however, in ∼25% of patients, CMR does not identify any myocardial injury. Identifying the underlying diagnosis has important clinical implications for patients' management and outcome. OBJECTIVES: The authors sought to assess whether the combination of CMR and peak troponin levels in patients with ACS and nonobstructive coronary arteries would lead to increased diagnostic yield. METHODS: Consecutive patients with ACS and nonobstructive coronary arteries without an obvious cause underwent CMR. The primary endpoint of the study was the diagnostic yield of CMR. The Youden index was used to find the optimal diagnostic cut point for peak troponin T to combine with CMR to improve diagnostic yield. Logistic or Cox regression models were used to estimate predictors of a diagnosis by CMR. RESULTS: A total of 719 patients met the inclusion criteria. The peak troponin T threshold for optimal diagnostic sensitivity and specificity was 211 ng/L. Overall, CMR has a diagnostic yield of 74%. CMR performed <14 days from presentation and with a peak troponin of ≥211 ng/L (n = 198) leads to an improved diagnostic yield (94% vs 72%) compared with CMR performed ≥14 days (n = 245). When CMR was performed <14 days and with a peak troponin of <211 ng/L, the diagnostic yield was 76% (n = 86) compared with 53% (n = 190) when performed ≥14 days. An increase in 1 peak troponin decile increases the odds of the CMR identifying a diagnosis by 20% (OR: 1.20; P = 0.008, 95% CI: 1.05-1.36). CONCLUSIONS: The combination of CMR performed <14 days from presentation and peak troponin T ≥211 ng/L leads to a very high diagnostic yield (94%) on CMR. The diagnostic yield remains high (72%) even when CMR is performed ≥14 days from presentation, but reduces to 53% when peak troponin T was <211 ng/L.

A Challenging and Unexpected Case of MINOCA Using Multimodality Imaging.

We describe a challenging case of a patient with MINOCA due to isolated right ventricular myocardial infarction with microvascular obstruction identified on cardiac magnetic resonance imaging. This case highlights that even a comprehensive, guideline-based assessment of these patients can initially fail to detect the underlying pathology. (Level of Difficulty: Beginner.).