Plaque composition in CT coronary angiography may distinguish type 1 MI from type 2 MI

A new study found that a higher low-attenuation coronary plaque burden distinguishes type 1 myocardial infarction from patients with type 2 myocardial infarction. The study results were published in the journal Radiology: Cardiothoracic Imaging.  

 Myocardial infarction (MI) is diagnosed when there is an evident acute myocardial injury in the setting of myocardial ischemia. Distinguishing type 1 and 2 MI is a common clinical conundrum that is difficult to resolve. Hence researchers conducted a secondary analysis of two studies to determine if quantitative plaque characterization can discriminate between type 1 and type 2 myocardial infarction by using CT coronary angiography (CTCA). A secondary analysis of two prospective studies that performed blinded quantitative plaque analysis on findings from CTCA in participants with type 1 myocardial infarction, type 2 myocardial infarction, and chest pain without myocardial infarction was done. Logistic regression analyses were performed to identify predictors of type 1 myocardial infarction. 

Results

• 155 participants with a mean age of 64 years had type 1 MI and 36 participants with a mean age, of 67 years who had type 2 myocardial infarction, and 136 participants with a mean age of 62 years who had chest pain without myocardial infarction participated in the study.
• There were greater total, noncalcified, and low-attenuation plaque burdens (P < .05 for all) in participants with type 1 myocardial infarction than those with type 2.
• When compared with those with chest pain without myocardial infarction, participants with type 2 myocardial infarction had similar low-attenuation plaque burden to (P = .4).
• Low-attenuation plaque was an independent predictor of type 1 myocardial infarction, with better discrimination than noncalcified plaque burden and maximal area of coronary stenosis.

Takeaway message: 

• CT coronary angiography can quantify important differences in the plaque composition of patients with type 1 and type 2 myocardial infarction. 
• Low-attenuation plaque burden provided strong discrimination between type 1 and type 2 myocardial infarction, independent of the severity of coronary stenosis or clinical characteristics. 
• Quantitative plaque analysis may help differentiate between patients with type 1 and type 2 myocardial infarction. 

Further reading: Meah MN, Bularga A, Tzolos E, et al. Distinguishing Type 1 from Type 2 Myocardial Infarction by Using CT Coronary Angiography. Radiology: Cardiothoracic Imaging. 2022;4(5). doi:10.1148/ryct.220081