Objectives: Elevated D-dimer levels on admission predict prognosis in patients undergoing primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI), but the association of D-dimer levels with structural markers of myocardial injury in these patients is unknown.
Methods: We performed cardiac magnetic resonance (CMR) imaging in 208 patients treated with primary PCI for STEMI. CMR was performed a median of 3 days after the index procedure. Of the 208 patients studied, 75 patients had D-dimer levels above the normal range on admission (>0.5 μg/mL; high D-dimer group) while 133 had normal levels (≤0.5 μg/mL; low D-dimer group). The primary outcome was myocardial infarct size assessed by CMR. Secondary outcomes included area at risk (AAR), microvascular obstruction (MVO) area, and myocardial salvage index (MSI).
Results: In CMR analysis, myocardial infarct size was larger in the high D-dimer group than in the low D-dimer group (22.3% [16.2-30.5] versus 18.8% [10.7-26.7]; p = 0.02). Compared to the low D-dimer group, the high D-dimer group also had a larger AAR (38.1% [31.7-46.9] versus 35.8% [24.2-45.3]; p = 0.04) and a smaller MSI (37.7 [28.2-46.9] versus 47.1 [33.2-57.0]; p = 0.01). In multivariate analysis, high D-dimer levels were significantly associated with larger myocardial infarct (OR 2.59; 95% CI 1.37-4.87; p<0.01) and lower MSI (OR 2.62; 95% CI 1.44-4.78; p<0.01).
Conclusions: In STEMI patients undergoing primary PCI, high D-dimer levels on admission were associated with a larger myocardial infarct size, a greater extent of AAR, and lower MSI, as assessed by CMR data. Elevated initial D-dimer level may be a marker of advanced myocardial injury in patients treated with primary PCI for STEMI.