Elevated inflammatory parameters are associated with lower platelet density in acute myocardial infarctions with ST-elevation.
OBJECTIVE
Platelets and granulocytes play important roles in coronary disorders. We therefore, investigated platelet and granulocyte alterations in myocardial infarctions (MIs).


METHODS
A total of 36 individuals having MI with raised ST-segments who were receiving thrombolytic therapy were studied. Sampling was carried out after thrombolysis within 24 h after hospital admission. After 3 to 6 months of recovery, 25 patients were reinvestigated. At the infarction, peak platelet density was determined using a special designed computerised apparatus. In addition, we did counts on platelets, 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 platelet density was analysed at the MI. All other parameters were determined at the acute event and at recovery.


RESULTS
At the MI, compared to the recovery, platelet counts were lower (P<0.001). In addition, increased neutrophil counts (P<0.001), elevated monocyte counts (P<0.001), enhanced myeloperoxidase (P<0.001) and interleukin 6 (P<0.001) levels were demonstrated. We failed to show elevated soluble P-selectin. Compared to individuals with ST-segment elevations and low platelet density (less than or = 1.058 kg/l), patients having peak platelet densities >1.058 kg/l displayed lower neutrophil counts (P<0.01) and decreased interleukin 6 levels (P<0.01). Furthermore, we demonstrate that individuals with higher inflammatory response at the MI had higher neutrophil (r = 0.6; P<0.01) and higher monocyte counts (r = 0.6; P<0.001) at recovery.


CONCLUSIONS
W conclude that MI is associated with an inflammatory response. However, a subgroup of patients having MI with ST-elevations and low peak platelet density was identified. Compared to subjects with higher platelet density, they had more severe inflammatory characteristics. The differences persisted during recovery.
Järemo
P
P
Department of Internal Medicine, Vrinnevisjukhuset, Norrköping, Sweden. petter.jaremo@beta.telenordia.se
Hansson
G
G
Nilsson
O
O
D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood*; D015850:Interleukin-6 / Q000097:blood; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000473:pathology; D009203:Myocardial Infarction / Q000097:blood* / Q000175:diagnosis; D009504:Neutrophils / Q000473:pathology; D019007:P-Selectin / Q000097:blood; D009195:Peroxidase / Q000097:blood; D010976:Platelet Count; D015912:Thrombolytic Therapy; D013997:Time Factors
D015415:Biomarkers; D015850:Interleukin-6; D019007:P-Selectin; D009195:Peroxidase