Malignancy in patients with myocardial infarction and non-obstructive coronary arteries: A systematic review and meta-regression

Background: The significance of malignancy in patients with myocardial infarction and non-obstructive coronary arteries (MINOCA) is poorly defined. This study aimed at determining the prevalence of malignancy and its association with long-term outcome in MINOCA. Methods: We searched the MEDLINE, EMBASE, and CENTRAL databases up to March 31, 2020 to identify studies reporting data on malignancy in full. We performed a random effects meta-analysis of proportions and assessed statistical heterogeneity using the I2 statistic and meta-regression analysis. Results: A total of 9 studies including 26,636 patients (11,910 men and 14,726 women) were selected for the meta-analysis. Of them, 655 patients (2.5%) had a diagnosis of malignancy at presentation. Comparison of presenting features and outcome between patients with MINOCA and patients with myocardial infarction and coronary artery disease (MI-CAD) showed that malignancy was significantly more common in the former as compared with the latter (p = 0.019). During a median follow-up of 39 months, 2,081 patients with MINOCA died (7.8%). Meta-regression analysis demonstrated that long-term mortality was associated with left ventricular ejection fraction (p = 0.0001; coefficient: -0.001; 95% CI: from -0.002 to 0.002), malignancy at presentation (p = 0.01; coefficient: 0.001; 95% CI: from -0.001 to 0.001), and use of beta-blockers during follow-up (p = 0.03; coefficient: 0.001; 95% CI: from -0.000 to 0.001). Conclusion: This study shows that the prevalence of malignancy in patients with MINOCA is not trivial and is significantly greater than in patients with MI-CAD. Malignancy is significantly associated with an unfavorable long-term prognosis in MINOCA.