Differences in inflammatory activity at the onset of acute myocardial infarction according to the clinical presentation of preinfarction angina

Abstract

It is unknown whether the pathogenetic mechanisms underlying acute myocardial infarction (AMI) differ according to the clinical presentation of preinfarction angina, so the present study measured plasma levels of C-reactive protein (CRP) in 280 patients with AMI in whom serum creatine kinase levels were normal on admission and increased subsequently. Patients were classified into 3 groups according to the type of preinfarction angina: no angina (n=95), stable angina (n=48), and unstable angina (n=137). Patients with unstable angina were subdivided according to the Braunwald classification: class IB (n=39), class IIB (n=22), and class IIIB (n=76). There were no differences among the 5 groups in baseline characteristics. CRP on admission was significantly higher and the level of physical activity at symptom onset was significantly lower in the Braunwald class IIIB group than in the other groups, but no differences were observed among the other groups. Patients with preinfarction Braunwald class IIIB unstable angina had higher CRP levels on admission and symptom onset at a lower level of physical activity. In such patients, the pathogenetic mechanisms may differ from those in other subsets of patients with AMI and active inflammation may play a more important role in AMI onset.