Late microvascular obstruction after acute myocardial infarction: relation with cardiac and inflammatory markers.

Objectives: We sought to assess the relation of late microvascular obstruction (l-MVO) size as quantified by cardiac magnetic resonance (CMR) imaging with cardiac and inflammatory marker concentrations after acute myocardial infarction (AMI).

Methods: CMR was performed in 118 consecutive patients within 8 days after successful interventional reperfused first acute ST-elevation AMI. Infarct volumes and l-MVO sizes were calculated from late enhancement (LE) sequences and functional parameters were determined from short-axis cine MR sequences. Creatine kinase (CK) and cardiac troponin T (cTnT), high-sensitivity C-reactive protein (hs-CRP) as well as lactate dehydrogenase (LD) concentrations were determined serially from day 1 to day 4 after symptom onset.

Results: L-MVO was detected in 66/118 patients (55.9%) and comprised 18.2 ± 10% of infarct size and 4.7 ± 3% of left ventricle myocardial mass. Each single-point, peak and cumulative release concentration of cTnT (r=0.44 to 0.73, p<0.0001), CK (r=0.21 to 0.76, p<0.0001), LD (r=0.36 to 0.82, all p<0.0001) as well as hs-CRP single-point values as assessed from day 1 to day 4 and its peak and cumulative release concentrations (r=0.24 to 0.49, p<0.003) significantly correlated with l-MVO size. Receiver operating curve (ROC) analysis indicated a cut-off value of 4.7 μg/l cTnT to best identify the presence of l-MVO (area under the curve (AUC) 0.904; 95% CI: 0.85-0.95; p<0.0001).

Conclusion: L-MVO sizes significantly correlate with cardiac and inflammatory marker concentrations as determined early after AMI. cTnT concentration of >4.7 μg/l could help to identify patients in whom l-MVO is present.