The association of serum neutrophil markers and acute coronary syndrome.

An association exists between chronic infection-induced inflammation, such as periodontitis, and acute coronary syndrome (ACS). We studied the association of serum neutrophil markers, myeloperoxidase (MPO), matrix metalloproteinase (MMP)-8, tissue inhibitor of metalloproteinase (TIMP)-1 concentrations and MMP-8/TIMP-1 ratio, with the risk of recurrent ACS. Radiographic periodontal status was recorded from 141 patients with acute non-Q-wave infarction or unstable angina pectoris, who participated in a double-blind, placebo-controlled study with clarithromycin for 3 months. Serum samples were collected within arrival to the hospital, at 1 week, 3 months and 1 year. Recurrent ACS events were registered during the 1-year follow-up. In the whole population, high serum MPO concentrations at 1 week (fourth quartile versus quartiles 1-3) were associated with the risk of recurrent ACS with a relative risk (RR) of 2.52 (95% CI, 1.277-4.980; P = 0.008). In patients without periodontal disease, high MPO concentration at 1 week and 1 year predicted recurrent ACS with RRs of 3.54 (1.600-7.831; P = 0.002) and 2.87 (1.171-7.038; P = 0.021), respectively. In the placebo group, but not in the clarithromycin group, high serum MMP-8/TIMP-1 ratio at 1 week predicted recurrent ACS with an RR of 3.23 (1.295-8.063; P = 0.012). Our results suggest that high serum neutrophil markers reflect increased risk of recurrent ACS, especially in patients without periodontal disease and not receiving antimicrobial medication.