[Significance of acute-phase inflammatory reactants as an indicator of prognosis after acute myocardial infarction: which is the most useful predictor?]

Abstract

Objectives: To investigate the relationship between representative acute-phase inflammatory reactants [highly sensitive C-reactive protein (hsCRP), serum amyloid A protein (SAA) and interleukin-6 (IL-6)] and the severity of acute myocardial infarction and patient prognosis, and to identify the most useful predictor of the three.

Methods: This study investigated 132 consecutive patients admitted within 8 hr of onset of first acute myocardial infarction and successfully reperfused with primary percutaneous coronary intervention. Acute-phase (= 24 hr from onset) blood samples were taken for evaluation of inflammatory reactants (hsCRP, SAA and IL-6), and peak creatine phosphokinase levels were measured every 4 hr after admission for 48 hr to assess myocardial infarction infarct size. Left ventriculography was performed in the chronic stage (20 +/- 9 days post-admission) to analyze left ventricular ejection fraction and regional wall motion, using Killip's classification to determine acute myocardial infarction severity. Logistic regression analysis was used to quantify the usefulness of the reactants as predictors of patient prognosis.

Results: Both hsCRP and SAA showed significant positive correlations with peak creatine phosphokinase. hsCRP and SAA showed significant inverse correlations with left ventricular ejection fraction and regional wall motion in the chronic stage. Multivariate analysis identified SAA as the best predictor of severe heart failure (Killip's classification III, IV). SAA was the best predictor of a major cardiac event (shock, cardiac death).

Conclusions: These results suggest a strong correlation between acute-phase SAA and the clinical course of patient outcomes after acute myocardial infarction, such as cardiac function, heart failure and cardiac death. SAA may be the most useful acute-phase inflammatory reactant for predicting the prognosis after acute myocardial infarction.