Increased platelet activation in patients with slow coronary flow.

We tested the hypothesis that increased platelet activation may be present in patients with slow coronary flow (SCF) and may contribute to the pathogenesis of slow coronary flow phenomenon (SCFP). Fifty patients angiographically proven normal coronary flow (control group; mean age = 61.3 +/- 7.0 years, 43 male) and 50 patients with angiographically proven SCF in all coronary arteries (patient group; man age = 62.7 +/- 6.7 years, 38 male) were included in the present study. Coronary flow rates of all subjects were documented by Thrombolysis In Myocardial Infarction frame count (TIMI frame count). Patients with a corrected TIMI frame count greater than two standard deviations from normal published range for the particular vessel were considered as having SCF. Complete blood count and mean platelet volume (MPV) was measured from whole blood sample with Abbott Cell-Dyne 4000 cell counter. Plasma sP-selectin concentrations were analyzed with sP-Selectin ELISA kit. There were no statistically significant differences between the two groups with respect to baseline demographic, clinical and lipid parameters. Not only MPV values but also plasma sP-selectin levels were significantly higher in patients with the patients with SCF compared to those of controls (for MPV; 8.2 +/- 0.7 vs. 7.2 +/- 0.6 fl, P < 0.001, for sP-Selectin; 1.5 +/- 0.3 vs. 1.0 +/- 0.2 ng/ml, P < 0.001). Interestingly, significant positive correlations were detected between mean TIMI frame counts and MPV and sP-selectin levels (for MPV; r = 0.56, P < 0.001, for sP-selectin r = 0.67, P < 0.001). The current study demonstrates that platelet activity is increased in the patients with SCF compared to that of the patients with normal coronary flow.