The Impact of Ischemic Time on the Predictive Value of High-Sensitivity C-Reactive Protein in ST-Segment Elevation Myocardial Infarction Patients Treated by Primary Percutaneous Coronary Intervention

Background and Objectives: The high-sensitivity C-reactive protein (hs-CRP), a marker of inflammation, has been known to be elevated in patients with coronary artery disease. However, there is controversy about the predictive value of hs-CRP after acute myocardial infarction (MI). Therefore, we evaluated the impact of ischemic time on the predictive value of hs-CRP in ST-segment elevation myocardial infarction (STEMI) patients who were treated by primary percutaneous coronary intervention (PCI). Subjects and Methods: We enrolled 5123 STEMI patients treated by primary PCI from the Korean Working Group in Myocardial Infarction and divided enrolled patients into four groups by symptom-to-balloon time (SBT) and level of hs-CRP (Group I: SBT <6 hours and hs-CRP <3 mg/L, Group II: SBT <6 hours and hs-CRP ${\geq}3$ mg/L, Group III: SBT ${\geq}6$ hours and hs-CRP <3 mg/L, and Group IV: SBT ${\geq}6$ hours and hs-CRP ${\geq}3$ mg/L). To evaluate the impact of ischemic time on the predictive value of hs-CRP in STEMI patients, we compared the cumulative cardiac event-free survival rate between these four groups. Results: The sum of the cumulative incidence of all-cause mortality and recurrence of MI was higher in Group IV than in the other groups. However, there was no significant difference among Group I, Group II, and Group III. The Cox-regression analyses showed that an elevated level of hs-CRP (${\geq}3$ mg/L) was an independent predictor of long-term cardiovascular outcomes only among late-presenting STEMI patients (p=0.017, hazard ratio=2.462). Conclusion: For STEMI patients with a long ischemic time (${\geq}6$ hours), an elevated level of hs-CRP is a poor prognostic factor of long-term cardiovascular outcomes.