Interleukin-6 and neutrophils are associated with long-term survival after acute myocardial infarction.
BACKGROUND
Assessing acute myocardial infarction (MI) with respect to long-term survival is not easy. Authorities in the field suggest that inflammation predicts short-range (up to 17 months) coronary death. It is not known whether long-term survival is associated with the inflammatory response. In this study, we evaluate the relationships between survival for more than 8 years and inflammation, i.e., circulating interleukin-6 (IL-6) and neutrophil counts, in acute MI.


METHODS
Patients with ST-segment elevation MIs (STEMI; n=33) and non-ST-segment MIs (non-STEMI; n=39) in 1996 were included in the study. All STEMI patients received thrombolytic therapy. Acute coronary angiography was not an option. Determination of IL-6 and neutrophils was carried out within 24 h after commencement of pain. The subjects were followed for more than 8 years (until December 31, 2005) using the national death registry. Inflammatory markers at the time of MI were compared with long-term survival (n=35).


RESULTS
At the time of acute MI, survivors for more than 8 years proved to have lower IL-6 (p<0.01) and decreased neutrophil counts (p<0.05). The differences remained (p<0.01 for both markers) when excluding deaths (n=11) occurring in 1996 and 1997. Subsequently, the subjects were divided into two equally sized groups, depending on their IL-6 values at the beginning of the study. As expected, a lower IL-6 was associated with a more favorable long-term prognosis (p<0.01).


CONCLUSIONS
Circulating IL-6 predicts long-term survival after acute MI. Neutrophils appear to have prognostic value as well.
Järemo
P
P
Department of Internal Medicine, The Vrinnevi Hospital, Norrköping, Sweden. petter.jaremo@beta.telenordia.se
Nilsson
O
O
D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000276:immunology* / Q000401:mortality*; D009504:Neutrophils / Q000276:immunology*; D012189:Retrospective Studies; D016019:Survival Analysis
D015415:Biomarkers; D015850:Interleukin-6