Increased circulating levels of standardized inflammatory and endothelial dysfunction biomarkers in patients with myocardial infarction with nonobstructive coronary arteries

Abstract Introduction Around 10% of patients with acute myocardial infarction (AMI) present with nonobstructive coronary arteries (MINOCA), for which the underlying pathophysiology is often uncertain. Our aim was to evaluate inflammatory burden and endothelial dysfunction in MINOCA patients by assessing biomarkers in both acute and stable phases. Methods An analytical and observational study at a University Hospital involving 166 MI patients admitted over the past 3years. Following ESC guidelines, patients were categorized into MINOCA or myocardial infarction with significant coronary artery disease (MI-CAD) groups. Circulating levels of inflammatory biomarkers (interleukin-6(IL-6), tumor necrosis factor-α(TNF-α) and high-sensitivity C-reactive protein(hs-CRP)) and of endothelial dysfunction (asymmetric dimethylarginine (ADMA)) were measured in 44 MINOCA patients and 122 MI-CAD patients at acute phase (admission and discharge) and stable phase (2months after MI). As biomarker levels may vary with MI size, each value was standardized by dividing it by the peak troponin, resulting in a biomarker/troponinT ratio. We evaluated the effects of standardized (SB) and non-standardized (NSB) biomarker values using a multivariate regression model adjusted for age and sex. Results We analyzed 166 patients (median age:68 years, 70% males). MI-CAD patients had higher peak high-sensitive troponinT (hs-TnT) levels upon admission compared to those with MINOCA (1491ng/L vs 247ng/L,p<0.001),likely due to larger infarctions generating higher levels of inflammation. When examining the association between infarct size, as measured by peak hs-TnT values, and biomarker levels, we observed a significant dose-response relationship for hs-CRP at admission (βcoefficient 0.16 [95%CI,0.02-0.29],p0.02) and IL-6 at admission (βcoefficient 0.15 [95%CI,0.04-0.27],p0.01). Significant positive associations were found between MINOCA and all SBs, both during the acute phase and in follow-up. During the acute phase ORs ranged from 1.35to2.7 (p<0.05) for inflammatory biomarkers and from 2.34 to 2.76 (p<0.01) for ADMA. In the stable phase ORs ranged from 1.49to3.06 (p<0.05) for inflammatory biomarkers, and OR was 2.79(p<0.01) for ADMA (Figure 1). In contrast, none of the NSBs were associated with MINOCA. Regarding temporal biomarker changes, during the acute phase of MI and 2 months post-event, both MINOCA and MI-CAD patients showed similar trends. However, MINOCA patients consistently maintained elevated inflammatory activity and ADMA concentrations only when biomarkers were standardized by infarct size (Figure 2). Conclusions Higher levels of SBs were consistently associated with MINOCA, both during the acute phase of the event and in follow-up, compared to MI-CAD. Consequently, this study suggests that the inflammatory burden, measured by heightened levels of standardized inflammatory biomarkers, and endothelial dysfunction, as measured by ADMA, may play a role in the pathophysiology of MINOCA.Boxplots for SBs at three time points.Temporal changes in biomarker levels.