Elevated inflammatory parameters are associated with lower platelet density in acute myocardial infarctions with ST-elevation

Platelets and granulocytes play important roles in coronary disorders. We t herefore, investigated platelet and granulocyte alterations in myocardial i nfarctions (MIs). Patients and study design: A total of 36 individuals havi ng MI with raised ST-segments who were receiving thrombolytic therapy were studied. Sampling was carried out after thrombolysis within 24 h after hosp ital admission. After 3 to 6 months of recovery, 25 patients were reinvesti gated. At the infarction, peak platelet density was determined using a spec ial designed computerised apparatus. In addition, we did counts on platelet s, neutrophils and monocytes. Moreover, plasma levels of soluble P-selectin , myeloperoxidase and interleukin 6 were determined to estimate the degree of platelet, neutrophil and monocyte activation, respectively. Peak platele t density was analysed at the MI. All other parameters were determined at t he acute event and at recovery. Results: At the MI, compared to the recover y, platelet counts were lower (P < .001). In addition, increased neutrophil counts (P < .001), elevated monocyte counts (P < .001), enhanced myelopero xidase (P < .001) and interleukin 6 (P < .001) levels were demonstrated. We failed to show elevated soluble P-selectin. Compared to individuals with S T-segment elevations and low platelet density (<less than or equal to>1.058 kg/l), patients having peak platelet densities >1.058 kg/l displayed lower neutrophil counts (P < .01) and decreased interleukin 6 levels (P < .01). Furthermore, we demonstrate that individuals with higher inflammatory respo nse at the MI had higher neutrophil (r = .6; P < .01) and higher monocyte c ounts (r = .6; P < .001) at recovery. Conclusion: We conclude that MI is as sociated with an inflammatory response. However, a subgroup of patients hav ing MI with ST-elevations and low peak platelet density was identified. Com pared to subjects with higher platelet density, they had more severe inflam matory characteristics. The differences persisted during recovery. (C) 2000 Elsevier Science Ltd. All rights reserved.