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The association between plaque characterization by CT angiography and post-procedural myocardial infarction in patients with elective stent implantation was found out through a study.

For the study, a total of 189 consecutive patients were enrolled; they underwent elective stent implantation after volumetric plaque analysis with 64-slice MDCT. Each plaque component and lumen (filled with dye) was defined as follows: 1) low-attenuation plaque (LAP) (<50 HU); 2) moderate-attenuation plaque (MAP) (50-150 HU); 3) lumen (151-500 HU); and 4) high-attenuation plaque (HAP) (>500 HU). The volume of each plaque component in the target lesion was calculated using Color Code Plaque. Post-procedural creatine kinase-MB isoform and troponin-T (TnT) at 18 hours after percutaneous coronary intervention were also evaluated.

The result obtained was that the volumes of LAP (87.9 ± 94.8 mm3 vs. 47.4 ± 43.7 mm3, p < 0.01) and MAP (111.6 ± 77.5 mm3 vs. 89.8 ± 67.1 mm3, p < 0.05) were larger in patients with post-procedural myocardial injury (defined as positive TnT) than in those with negative TnT. The volumes of LAP and MAP and fraction of LAP in total plaque (LAP volume/total plaque volume) correlated with biomarkers; the MAP fraction was inversely correlated with biomarkers. The volume of LAP was an independent predictor of positive TnT after adjusting for patient background, conventional intravascular ultrasound parameters, and procedural factors.

The authors concluded that post-procedural myocardial injury was associated with the volume and fraction of LAP, as detected by MDCT.

This pilot study suggests a significant correlation between LAP volume within target lesions, as measured by MDCT, and post-procedural elevation of cardiac biomarker levels. The LAP volume was found to be an independent predictor of myocardial injury after elective stenting. Plaque evaluation by MDCT may, therefore, provide useful information to identify high-risk patients who are expected to have a better outcome with aggressive medical treatment or bypass surgery. However, evaluation of coronary plaque by MDCT involves significant exposure to radiation as well as use of iodinated contrast medium. 

Source: JACC

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