P6404Myocardial infarction with nonobstructive coronary arteries: does aspirin have a place in the treatment of this entity?

Abstract Background Myocardial infarction with nonobstructive coronary arteries (MINOCA) is still a clinical enigma that is being increasingly recognised, as the number of coronary angiographies we perform in our centres also increase. However, the treatment for this entity is still a matter of important debate, not only due to the different causative mechanisms of this disease but also because there are no major trials regarding MINOCA treatment. Purpose To determine the association between acetylsalicylic acid (ASA) use after discharge and mortality after discharge in MINOCA patients admitted to a coronary care unit (CCU). Methods We analyzed data from 370 (11.7% of the global sample) patients admitted with MINOCA in our CCU. Patients with other final diagnoses, missing mortality data, previous acute myocardial infarction, contra-indications to aspirin and known heart failure before admission were excluded. All patients underwent transthoracic echocardiography and coronary angiography at any point during hospitalisation. After adjusting data for relevant comorbidities we then compared mortality after hospital discharge between the ASA group and the no-ASA group. Results Of all MINOCA patients admitted in our CCU, 84 (22.7%) were diagnosed with ST-elevation myocardial infarction (STEMI) and 286 (77.3%) with non-ST elevation myocardial infarction (NSTEMI). 296 (80%) patients received ASA after discharge. Both groups were homogeneous as we did not find any significant differences between groups regarding age (p=0.106), left ventricle ejection fraction (p=0.100), GRACE score at hospitalisation (p=0.150), Killip-Kimball class at hospitalisation (p=0.604), incidence of acute kidney injury (p=0.450), maximum c-reactive protein during stay (p=0.804) and low-density lipoprotein levels at hospitalization (p=0.055). There was also no difference in the incidence of diabetes (p=0.350), exposure to daily stress (p=0.767), active smoking (p=0.569), dyslipidemia (p=0.229), hypertension (p=0.057) and type of myocardial infarction (STEMI vs NSTEMI – p=0.215). In this MINOCA cohort (5 years follow-up) a total of 47 patients died (12.7%). ASA vs. no-ASA 1-month (3.1% vs. 0.0%, p=0.214), 6-month (4.5% vs. 1.4%, p=0.317), 1-year (5.9% vs 5.6%, p=0.900), 3-year (10.5% vs. 8.3%, p=0.668) and 5-year (13.3% vs. 12.5%, p=0.860) all-cause mortality was not significantly different. The same non-significant trend towards higher mortality with ASA was obtained when survival curves were taken into account. Conclusions MINOCA remains a challenging entity. In our study, the systematic use of ASA in all patients following MINOCA was not associated with better survival after long-term follow-up.