RESUMO
BACKGROUND: This study aimed to evaluate the medium-term prognostic implications of cardiac magnetic resonance (CMR) imaging in patients with myocardial infarction with non-obstructive coronary arteries (MINOCA). METHODS: A systematic literature search of Embase, PubMed, and The Cochrane Library was performed. Eligible studies reported outcomes of CMR-assessed MINOCA with a mean follow-up period of >6 months. The primary endpoint was all-cause death. Secondary endpoints included cardiac death, reinfarction, and cardiovascular rehospitalisation. The pooled effect sizes with 95% confidence interval (CIs) were estimated using a random effect model. RESULTS: A total of 3,050 patients from twenty-one studies were included in the meta-analysis. The prevalence of myocarditis, "true" myocardial infarction, Takotsubo cardiomyopathy, and normal CMR imaging was 36%, 25%, 14%, and 19%, respectively. Pooled data showed that the annualised event rates for all-cause mortality, cardiac mortality, reinfarction, and cardiovascular rehospitalisation were 1.01% (95% CI 0.59%-1.51%), 0.06% (95% CI 0.00%-0.39%), 0.68% (95% CI 0.18%-1.38%), and 5.67% (95% CI 3.11%-8.85%), respectively. Compared with patients with a diagnosis of myocarditis on CMR, patients with Takotsubo cardiomyopathy (RR 7.11; 95% CI 3.04-16.66) and "true" myocardial infarction (RR 3.82; 95% CI 1.65-8.86) were associated with a significantly higher risk of all-cause mortality, whereas a similar risk of all-cause mortality was observed in patients with normal imaging (RR 1.01; 95% CI 0.28-3.59). No association was found between CMR diagnoses and the risk of secondary endpoints in MINOCA. CONCLUSIONS: In patients with MINOCA assessed by CMR, the overall absolute incidence rates of mortality and reinfarction were low. However, certain imaging diagnoses were associated with a higher risk of all-cause mortality, with most deaths attributed to non-cardiac causes. Additionally, these patients experienced a high burden of cardiovascular rehospitalisation. REGISTRATION: PROSPERO (CRD42022323615).
