PLASMA-PROTEIN ACUTE-PHASE RESPONSE IN UNSTABLE ANGINA IS NOT INDUCEDBY ISCHEMIC-INJURY

Background Elevated levels of C-reactive protein (CRP) are associated with an unfavorable clinical outcome in patients with unstable angina. To determine whether ischemia-reperfusion injury causes this acute-ph ase response, we studied the temporal relation between plasma levels o f CRP and ischemic episodes in 48 patients with unstable angina and 20 control patients with active variant angina, in which severe myocardi al ischemia is caused by occlusive coronary artery spasm. Methods and Results Blood samples were taken on admission and subsequently at 24, 48, 72, and 96 hours. All patients underwent Holter monitoring for the first 24 hours and remained in the coronary care unit under ECG monit oring until completion of the study. On admission, CRP was significant ly higher in unstable angina than in variant angina patients (P<.001). In unstable angina, 70 ischemic episodes (1.5+/-2 per patient) and in variant angina 192 ischemic episodes (9.6+/-10.7 per patient) were ob served during Holter monitoring (P<.001), for a total ischemic burden of 14.8+/-30.2 and 44.4+/-57.2 minutes per patient, respectively (P<.0 01). The plasma concentration of CRP did not increase in either group during the 96 hours of study, even in patients who had episodes of isc hemia lasting >10 minutes. Conclusions The normal levels of CRP invari ant angina, despite a significantly larger number of ischemic episodes and greater total ischemic burden, and the failure of CRP values to i ncrease in unstable angina indicate that transient myocardial ischemia , within the range of duration observed, does not itself stimulate an appreciable acute-phase response.