The Association Between Plaque Characterization by CT Angiography and Post-Procedural Myocardial Infarction in Patients With Elective Stent Implantation

OBJECTIVES: This study sought to evaluate the association between volumetric characterization of target lesions by multidetector computed tomography (MDCT) angiography and the risk of post-procedural myocardial injury after elective stent implantation. Previous reports have shown that plaque characterization of the target lesion may provide useful information for stratifying the risk of coronary stenting.

METHODS: 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 to 150 HU); 3) lumen (151 to 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 h after percutaneous coronary intervention were also evaluated.

RESULTS: 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 IVUS parameters, and procedural factors.

CONCLUSIONS: Post-procedural myocardial injury was associated with the volume and fraction of LAP as detected by MDCT. The volume of LAP was an independent predictor of positive TnT. Plaque analysis by MDCT would be a useful method for predicting post-procedural myocardial injury after percutaneous coronary intervention. B.J. Hill Jersey

PMID: 20129526

Posted in * Journal Club Selections, Computed Tomography and tagged , , , , , .

2 Comments

  1. Low attenuation plaque has previously been identified as a marker of future events.

    See post from July 21, 2009:

    Computed Tomographic Angiography Characteristics of Atherosclerotic Plaques Subsequently Resulting in Acute Coronary Syndrome.
    Motoyama S, Sarai M, Harigaya H, Anno H, Inoue K, Hara T, Naruse H, Ishii J, Hishida H, Wong ND, Virmani R, Kondo T, Ozaki Y, Narula J.
    J Am Coll Cardiol. 2009; 54(1):49-57.
    PMID:

    Also read associated manuscript:

    *Is CT the better angiogram: Coronary interventions and CT Imaging.
    Achenbach S and Ludwig J.
    J Am Coll Cardiol: Cardiovasc Imaging 2010; 29-31.
    *To view, you must have online access/hard copy of JACC.

  2. Like stated in many posts and their added comments before this one, plaque characterization by CT and the concept of ‘vulnerable’ plaque seem to be gaining more and more attention in the literature.

    This study is interesting in many aspects. I would like to highlight the authors decision to divide plaque not in 2 but in 3 different classes, adding a ‘moderate-attenuation’ (MAP) category to the more common low- and high-attenuation ones (soft and calcified plaque, respectively). This led to a thought provoking finding: it showed “that low-attenuation plaque (LAP) and MAP volumes were larger in patients who had an MI after stent implantation. The MAP volume correlated positively and MAP fraction in plaque correlated inversely with biomarkers. On the other hand, both the volume of LAP and its fraction correlated positively with biomarkers. These findings suggest that MAP volume does not essentially contribute to a post-procedural elevation of cardiac biomarkers.” LAP is defined as measuring less than 50 HU in attenuation.

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