Serum C-reactive protein concentration in acute myocardial infarction and its relationship to mortality during 24 months of follow-up in patients under thrombolytic treatment

OBJECTIVES: We studied the relationship between serum C-reactive protein and mortality in acute myocardial infarction. BACKGROUND: Early recanalization of an infarct-related coronary artery is considered to be an essential prerequisite for reducing mortality by thrombolytic treatment in acute myocardial infarction. It also reduces the inflammatory reaction caused by acute myocardial infarction and is measurable by determination of serum C-reactive protein concentrations. We therefore studied the prognostic value of determining serum C-reactive protein in acute myocardial infarction. METHODS: We measured serum C-reactive protein concentrations daily for 6 days and creatine kinase, as well as its MB isoenzyme concentrations twice a day, for 3 days after a myocardial infarct, in 188 consecutive patients selected for thrombolytic therapy and treated in the same University Hospital Coronary Care Unit. The highest serum concentrations were related to total mortality as well as to the causes of death 3, 3-6, 6-12 and 12-24 months after the onset of the myocardial infarction. RESULTS: The highest serum concentrations of serum C-reactive protein were observed 2 to 4 days after the onset of myocardial infarction. The mean value of the highest serum concentration of C-reactive protein in patients who survived the whole 24-month study period was 65 mg. 1(-1), with the 95% confidence intervals for the mean ranging from 58 to 71. The corresponding values in those who died within 3, 3-6, 6-12 and 12-24 months were 166 (139-194), 136 (88-184), 85 (52-119) and 74 (38-111) mg.1(-1), respectively. The values in those who died within 3 and 3-6 months of the infarction differed statistically significantly from the values in those who survived the whole period (P < 0.001 and P < 0.05, respectively). In patients who died due to congestive heart failure the mean highest serum C-reactive protein concentration was 226 (189-265) mg.1(-1). In those who suffered sudden cardiac death and those who died from a new myocardial infarction or non-cardiac causes, the respective values were 167 (138-196), 64 (38-89) and 48 (10-86) mg. 1(-1). The values in those who died due to congestive heart failure and those suffering sudden cardiac death differed statistically significantly (P < 0.001) from the values of those who survived or died due to other causes. The highest serum concentrations of creatine kinase or its MB isoenzyme were not associated with mortality in this study. CONCLUSIONS: High serum C-reactive protein concentrations in acute myocardial infarction patients treated with thrombolytic drugs predict increased mortality up to 6 months following the infarction. Accordingly, reduction of inflammatory reaction by successful thrombolytic treatment may make an important contribution to the survival benefit of thrombolytic treatment of acute myocardial infarction.