Increased plasma C-reactive protein and interleukin-6 concentrations in patients with slow coronary flow.

Background: Slow coronary filling of epicardial coronary arteries in the absence of stenosis is not infrequently detected finding during routine coronary angiography. There is mounting evidence suggested that an inflammatory process play an important role in atherosclerotic pathogenesis appeared in different clinical settings. However, the possible association between inflammation and slow coronary flow (SCF) has not been investigated. We examined whether the increased inflammatory markers are present in patients with SCF.

Methods: Forty-two patients with SCF detected by coronary angiography via the Thrombosis In Myocardial Infarction (TIMI) frame count method were enrolled in this study. The plasma concentration of high-sensitivity C-reactive protein (CRP) and interleukin-6 (IL-6) were evaluated using commercial available kits. Data were compared with 30 control subjects with angiographically normal coronary flow.

Results: There are no differences regarding clinical characteristics between the 2 groups. The data showed, however, that plasma CRP and IL-6 concentrations were higher in patients with SCF compared with normal control subject (CRP: 0.27 +/- 0.16 vs. 0.22 +/- 0.11mg/l; and IL-6: 8.7 +/- 0.8 vs. 5.4 +/- 0.4pg/ml, p < 0.01 respectively). In addition, mean TIMI frame count was positively correlated with plasma CRP and IL-6 concentrations (CRP: gamma = 0.551; IL-6: gamma = 0.573, p < 0.01 respectively).

Conclusions: Plasma concentration of CRP and IL-6 concentrations increased, and was positive correlated with TIMI frame count in patients with SCF compared with normal coronary flow subject. Therefore, whether the increased inflammatory markers are related to the pathogenesis of SCF in these patients deserved further investigation.