Yonsei Med J.  2011 Nov;52(6):914-922. 10.3349/ymj.2011.52.6.914.

Association of Lipoprotein-Associated Phospholipase A2 with Characteristics of Vulnerable Coronary Atherosclerotic Plaques

• Liu YS
• Hu XB
• Li HZ
• Jiang WD
• Wang X
• Lin H
• Qin AQ
• Wang YM
• Zhao T
• Dong ZQ
• Zhang M
• Lu QH

• KMID: 1058810
• DOI: http://doi.org/10.3349/ymj.2011.52.6.914

Abstract

PURPOSE
Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an inflammatory enzyme expressed in atherosclerotic plaques. We investigated the association of circulating Lp-PLA2 with characteristics of vulnerable coronary atherosclerotic plaques.
MATERIALS AND METHODS
We recruited 113 patients with either unstable angina (UA, n=59) and stable angina (SA, n=54) by coronary angiography. Thirty-six healthy subjects served as controls. Intravascular ultrasound (IVUS) was used to evaluate the characteristics of coronary atherosclerotic plaque, and serum Lp-PLA2 concentration was measured as well.
RESULTS
Lp-PLA2 concentration was significantly higher in both UA and SA patients [(396+/-36) microg/L and (321+/-39) microg/L, respectively] compared with the controls [(127+/-49) microg/L, p<0.01], and higher in UA than SA group. IVUS findings showed that remodeling index (RI) (0.91+/-0.15 vs. 0.85+/-0.11, p=0.005) and eccentricity index (EI) (0.73+/-0.16 vs. 0.65+/-0.22, p=0.039) were larger in UA than in SA group, and fibrous caps were thicker in SA than UA group [(0.91+/-0.23) mm vs. (0.63+/-0.21) mm, p=0.032]. Moreover, Lp-PLA2 correlated positively with EI (r=0.439, p<0.01) and RI (r=0.592, p<0.05) in UA group. There was an inverse relationship between Lp-PLA2 and fibrous cap thickness in both UA (r=-0.587, p<0.001) and SA (r=-0.318, p<0.05) groups. The independent risk factors in UA group were Lp-PLA2 (OR=1.055, 95% CI: 1.03-1.08, p=0.013), LDL-cholesterol (OR=0.032, 95% CI: 0.00-0.05, p=0.041) and fibrous cap thickness (OR=0.008, 95% CI: 0.00-0.45, p=0.019). Lp-PLA2 was strongly associated with both EI and fibrous cap thickness in both groups.
CONCLUSION
Serum level of Lp-PLA2 is associated with both eccentricity index and fibrous cap thickness in both UA and SA groups. Elevated levels of circulating Lp-PLA2 might to be a strong risk factor and more serious for unstable angina than stable angina.

Keyword

Vulnerable plaque; lipoprotein-associated phospholipase A2; atherosclerosis

MeSH Terms

1-Alkyl-2-acetylglycerophosphocholine Esterase/*blood
Adult
Aged
Aged, 80 and over
Angina, Stable/*blood/enzymology/*pathology
Angina, Unstable/*blood/enzymology/pathology
Coronary Angiography
Coronary Artery Disease/*blood/enzymology/*pathology
Female
Humans
Male
Middle Aged

Figure

• 

  Fig. 1 Serum concentions of Lp-PLA2 in control subjects, SA group, and UA group. *p<0.01, compared with control. †p=0.014, compared with SA group. Lp-PLA2, lipoprotein-associated phospholipase A2; SA, stable angina; UA, unstable angina.

• 

  Fig. 2 Coronary angiography shows (A) single coronary lesion and (B) multiple coronary lesions.

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  Fig. 3 IVUS image of control shows one patient with chest pain and no stenosis found by coronary angiography; compared with SA group, IVUS image of UA group shows vulnerable plaque. IVUS, intravascular ultrasound; SA, stable angina; UA, unstable angina.

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  Fig. 4 Correlation of serum level of Lp-PLA2 with eccentricity index (A), remodeling index (B) and fibrous cap (C) in UA and SA groups. Solid line, fit line for UA group; dotted line, fit line for SA group. UA, unstable angina; SA, stable angina.

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