Abstract 12946: High levels of Systemic Myeloperoxidase are associated with Coronary Plaque Erosion in Patients with Acute Coronary Syndrome: a Clinicopathological Study
Background: Systemic levels of Myeloperoxidase (MPO) are a marker of inflammation and of plaque vulnerability in patients with acute coronary syndromes (ACS).
Hypothesis: We assessed the hypothesis that elevations in MPO levels may reflect different culprit lesion morphologies, such as plaque rupture or plaque erosion, with luminal thrombi.
Methods: Consecutive patients with ACS were enrolled. Optical coherence tomography was used to classify the culprit lesion as ruptured or eroded and detect luminal thrombus. Serum levels of MPO and of high sensitivity C-reactive protein (CRP) were measured in the peripheral circulation on admission before coronary angiography. In addition, ruptured and eroded plaques with overlying thrombi from postmortem coronary specimens of sudden death victims underwent immunohistochemical analysis with primary antibodies against MPO. The density of MPO positive cells in the plaque area (fibrous cap in ruptures or thrombus/plaque interface in erosions) and in thrombi was measured.
Results: Twenty-five patients, 67±11 yrs old, 15 (60%) males, 13 (52%) with non-ST elevation-ACS and 12 (48%) with acute ST elevation myocardial infarction were enrolled. The culprit lesion was classified as ruptured in 18 (72%) or eroded in 7 (28%) patients. Thrombus was detected in 16 (89%) of ruptured and in all eroded plaques. Baseline MPO levels were significantly higher in patients with an eroded plaque as compared to those with a ruptured plaque [2500 ng/ml (1415–2920) vs. 707 ng/ml (312–943), p=0.001], while CRP levels did not significantly differ between groups [11.3 mg/l (1.3–28.5) vs. 3.9 mg/l (1.3–17.8), p=0.76, respectively]. In postmortem specimens, the density of MPO positive cells within thrombi overlying plaques was significantly higher in lesions with erosion (n=11) than ruptures (n=11) [1584 (1088–2135) cell/mm2 vs. 579 (442–760) cells/mm2, p=0.0012], whereas in the plaque area no significant differences were observed between groups [erosions: 301 (176–617) cells/mm2 vs. ruptures: 291 (225–1122) cells/mm2), p=0.97].
Conclusions: This study shows that elevations in MPO reflect specific acute complications of coronary atherosclerosis, such as plaque erosion with luminal thrombi.
- © 2010 by American Heart Association, Inc.