Abstract 20186: Additive Value of Malondialdehyde-Modified Low-Density Lipoprotein As an Adjunct to 64-slice Cardiac Computed Tomographic Angiography for Diagnosing Acute Coronary Syndromes
Background: Circulating malondialdehyde-modified low-density lipoprotein (MDA-LDL) is a biomarker reflecting plaque instability, and increase in the setting of acute coronary syndrome. Although 64-slice cardiac computed tomographic angiography (CCTA) provides anatomical information of obstructive coronary disease and useful for diagnosing acute coronary syndrome (ACS), lower specificity and positive predictive value (PPV) raise clinical concern. This study was aimed at assessing whether the plasma levels of malondialdehyde-modified low-density lipoprotein (MDA-LDL) added to the diagnostic value of CCTA.
Methods: We prospectively studied 110 patients (72±11 years of age, 35% female) with chest pain possibly ischemic in origin without new ECG change. The patients underwent 64-slice CCTA and the assessment of the plasma level of MDA-LDL by using the immunoassay ELISA method. The diagnostic values of CCTA alone and those of the combination of the 2 methods (CCTA plus MDA-LDL) in diagnosing ACS on invasive coronary angiography were compared.
Results: CCTA showed normal coronary vessels in 9 patients, nonobstructive plaque in 26 patients (CCTA-negative patients), and obstructive coronary disease (≥50% luminal narrowing) in 75 (CCTA-positive patients). Followed by invasive coronary angiography, ACS was diagnosed in 42 of the 75 CCTA-positive patients (CCTA sensitivity 100% [42/42], specificity 68% [35/68], PPV 56% [42/75], and negative predictive value (NPV) 100% [35/35]). The MDA-LDL levels were significantly higher in subjects with ACS than in those without ACS (198±49 vs. 108±36, p<0.001). Receiver-operating-characteristic analysis showed that MDL-LDL levels greater than 173 IU was the optimal cutoff for detecting ACS. Combining CCTA with MDA-LDL levels (at a cutoff of 173) improved the specificity and PPV (CCTA specificity 87% [59/68]) and PPV 82% [42/51], respectively) for ACS diagnosis without decrease in sensitivity and NPV.
Conclusions: The circulating MDA-LDL levels provide incremental diagnostic value over CCTA for identifying patients with ACS. The combination of biomarker analysis by MDA-LDL and anatomical assessment by CCTA might play a potentially important role in the noninvasive diagnosis of ACS.
- © 2010 by American Heart Association, Inc.