Role of inflammation in Myocardial Infarction with Non-Obstructive Coronary Arteries

Abstract

Abstract Background The characteristics of patients with Myocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA) differ from those with Myocardial Infarction with Obstructive Coronary Artery Disease (MI-CAD). Thus, the mechanisms involved, such as inflammation, may be different. The objective of this study is to analyze the relationship between pro-inflammatory conditions and MINOCA, as well as the impact on their prognosis. Methods An analytical and observational study, including all patients admitted to our hospital with myocardial infarction and who underwent coronary angiography in the last four years (2016–2020; n=712). According to the definitions of the 2019 AHA Scientific Statement on Diagnosis and Management of MINOCA and ESC 2020 guidelines on Acute Coronary Syndromes in Patients Presenting without Persistent ST-Segment Elevation, we classified the patients into two groups: MI-CAD (n=643) and MINOCA (n=69). Besides general data, we recorded specific information about pro-inflammatory conditions (prevalence of autoimmune diseases, connective tissue disorders, and active infections and neoplasms). We also assessed C-reactive protein (C-RP) at admission, peak CK-MB and troponin levels. Follow-up analysis included death from any cause, major adverse cardiac events (MACE: cardiac death, MI, stroke), readmissions due to cardiovascular causes, and in-hospital mortality. Results The composite of pro-inflammatory conditions (autoimmune pathologies, connective tissue diseases and active cancer and infections) was significantly higher in the MINOCA group (30.4% vs 14.6%, p<0.001). Patients with MINOCA had higher rates of connective tissue disorders (5.8% vs 1.4%, p 0.01), and autoimmune diseases (14.5% vs 7.8%, p 0.058) tended to be more frequent in these patients. However, MINOCA patients had lower C-RP levels (180 vs 206mg/L, p<0.001), probably because they have smaller infarcts (peak CK-MB: 228 vs 325 U/L, p<0.001; high-sensitivity cardiac troponin T levels: 111 vs 176ng/L, p<0.001). In the follow-up of MINOCA patients, MACE did not occur more frequently in those patients with inflammatory conditions (4.8% vs 13%, p 0.3) than those without them. Moreover, pro-inflammatory disorders were not related to significantly higher mortality from any cause (8.7% vs 10%, p 0.86) nor readmissions due to cardiovascular causes (19.6% vs 23.8%, p 0.6). Our median follow-up was 29 months. There were no differences in in-hospital mortality. Conclusion This study suggests that pro-inflammatory disorders may be a risk factor for developing MINOCA without resulting in an unfavourable short- and long-term prognosis. Further research is needed to confirm this finding and identify its optimal management. Funding Acknowledgement Type of funding sources: None.