Identification of Diagnostic Markers for MINOCA in ST-Segment Elevation Myocardial Infarction Patients

John Michael Hoppe¹Michael Christoph Schramm¹Kathrin Diegruber¹David Esser¹Steffen Massberg¹Christopher Stremmel^2*

• ¹LMU Klinikum, Munich, Germany
• ²LMU Munich University Hospital, Munich, Germany

Abstract Introduction: Coronary artery disease remains the leading cause of death globally, with ST-segment elevation myocardial infarction (STEMI) requiring immediate intervention. However, some STEMI patients are later diagnosed with myocardial infarction with non-obstructive coronary arteries (MINOCA). Differentiating MINOCA is challenging and often hampered by limited access to advanced imaging. This study examines MINOCA patient characteristics and explores whether demographics, routine laboratory, and ECG findings can help differentiate MINOCA subgroups in the absence of advanced imaging. Methods: We conducted a retrospective single-center study of 2,553 suspected consecutive STEMI cases between 2013 and 2023. After excluding acute obstructive coronary artery disease and missing data, 296 patients were analyzed based on final diagnosis and compared by clinical, laboratory and diagnostic characteristics. Results: Among 296 patients, 205 (69.3%) met MINOCA criteria. Coronary causes (9.1%) included embolism and plaque rupture. Cardiac non-coronary causes (47.6%) included (peri-) myocarditis, non-STEMI (NSTEMI) type 2, and Takotsubo cardiomyopathy. Non-cardiac causes (5.4%), such as pulmonary embolism and aortic dissection, were less common. NSTEMI type 1 occurred in 3.7%, and 27.0% had no identifiable cause. Patients with (peri-) myocarditis were significantly younger, had lower BMI, higher CK and CRP levels, and more frequent ST-segment elevations. In contrast, NSTEMI type 2 patients were older, more often in shock, had more comorbidities, and used cardiovascular medications more frequently. Conclusion: In the absence of advanced imaging, routine clinical and laboratory parameters can provide critical information to differentiate MINOCA subtypes and guide the urgency of downstream diagnostic tests. In resource-limited settings, they could provide a framework for future risk-based scoring systems to optimize imaging use and improve patient care.