Serum Concentrations of Matrix Metalloproteinase-1 and Procollagen Type I Carboxy Terminal Propeptide Discriminate Infarct-Like Myocarditis and Non-ST-Segment-Elevation Myocardial Infarction.

Background: Biomarkers simplifying the diagnostic workup by discriminating between non-ST-segment-elevation myocardial infarction (NSTEMI) and infarct-like myocarditis are an unmet clinical need.
Methods and Results: A total of 105 subjects were categorized into groups as follows: ST-segment-elevation myocardial infarction (n=36), NSTEMI (n=22), infarct-like myocarditis (n=19), cardiomyopathy-like myocarditis (n=18), and healthy control (n=10). All subjects underwent cardiac magnetic resonance imaging, and serum concentrations of matrix metalloproteinase-1 (MMP-1) and procollagen type I carboxy terminal propeptide (PICP) were measured. Biomarker concentrations in subjects presenting with acute coronary syndrome and non-ST-segment-elevation, for example NSTEMI or infarct-like myocarditis, categorized as the non-ST-segment-elevation acute coronary syndrome-like cohort, were of particular interest for this study. Compared with healthy controls, subjects with myocarditis had higher serum concentrations of MMP-1 and PICP, while no difference was observed in individuals with myocardial infarction. In the non-ST-segment-elevation acute coronary syndrome-like cohort, MMP-1 concentrations discriminated infarct-like myocarditis and NSTEMI with an area under the receiver operating characteristic curve (AUC) of 0.95 (95% CI, 0.89-1.00), whereas high-sensitivity cardiac troponin T performed inferiorly (AUC, 0.74 [95% CI, 0.58-0.90]; P =0.012). Application of an optimal MMP-1 cutoff had 94.4% sensitivity (95% CI, 72.7%-99.9%) and 90.9% specificity (95% CI, 70.8%-98.9%) for the diagnosis of infarct-like myocarditis in this cohort. The AUC of PICP in this context was 0.82 (95% CI, 0.68-0.97). As assessed by likelihood ratio tests, incorporating MMP-1 or PICP with age and C-reactive protein into composite prediction models enhanced their diagnostic performance.
Conclusions: MMP-1 and PICP could potentially be useful biomarkers for differentiating between NSTEMI and infarct-like myocarditis in individuals with non-ST-segment-elevation acute coronary syndrome-like presentation, though further research is needed to validate their clinical applicability.