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Coronary Imaging on MRI and Myocardial Injury After PCI | Journal Scan
Study Questions:
Does the presence of high-intensity coronary plaque (HIP) on magnetic resonance imaging (MRI) predict myocardial injury after percutaneous coronary intervention (PCI)?
Methods:
This study performed noncontrast coronary MRI using T1-weighted imaging in 77 patients with stable angina prior to PCI, and compared rates of myocardial injury after PCI between groups. Troponin-T was measured at baseline and 24 hours after PCI; myocardial injury was defined as an increase in troponin to >5 times the 99th percentile of the upper reference limit. Intravascular ultrasound (IVUS) was performed, and IVUS findings were also compared between groups.
Results:
The presence of HIP was observed in 31/77 patients. There were no significant differences between groups in patient characteristics, medications, or clinical outcomes including stroke, clinical myocardial infarction, or mortality. Patients with HIP (vs. without) had increased plaque cross-sectional area, positive remodeling, ultrasound attenuation, intracoronary thrombus, lipid area, and lipid volume noted on IVUS (p < 0.01 for each). There were no significant differences in median (interquartile) troponin between groups at baseline [0.01 (0.01-0.02) for each group, p 0.56]; there was a significantly greater increase in troponin at follow-up in patients with HIP [0.07 (0.02-0.31) vs. 0.02 (0.01-0.03), p < 0.001]. PCI-related myocardial injury was observed in 18/31 (58%) with HIP and 5/46 (11%) without HIP on MRI (p < 0.001). On multivariable analysis, the only independent variable associated with PCI-related myocardial injury was the presence of HIP on MRI (odds ratio, 5.6; p = 0.02).
Conclusions:
The presence of HIP on coronary MRI is associated with vulnerable plaque, as identified on IVUS. Patients with HIP have an increased rate of PCI-related myocardial injury.
Perspective:
PCI-related myocardial injury is common, and this study compares the rate of this event to the presence of plaque characteristics on both MRI and IVUS. After adjusting for other characteristics (including IVUS findings), only the presence of HIP was significantly associated with PCI-related myocardial injury. These findings suggest that MRI may be useful to identify patients at risk. This may be helpful in clinical research, but it is not clear how this would change clinical care. It is unknown whether knowledge of this potential risk prior to PCI would alter plans for revascularization or change outcomes. While PCI-related myocardial injury is associated with worse outcomes, the magnitude of observed troponin elevation was very small, and there were no significant differences in the rate of clinical events.
Keywords: Angina Pectoris, Angina, Stable, Coronary Artery Disease, Lipids, Ultrasonography, Interventional, Magnetic Resonance Imaging, Myocardial Infarction, Percutaneous Coronary Intervention, Plaque, Atherosclerotic, Stroke, Thrombosis, Troponin, Troponin T
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