Patients with a history of stable or unstable coronary heart disease have different acute phase responses to an inflammatory stimulus

CRP concentration increased significantly after vaccination in both groups (Group 1: 0.47 [0.21-0.86] to 0.56 [0.32-1.17] mg/L, p = 0.005; Group 2: 0.64 [0.21-1.09] to 0.75 [0.33-1.48] mg/L, p = 0.003), without significant differences between groups in absolute or percentage changes. By contrast, SAA did not change after vaccination in Group 1 (14.4 [8.9-19.5] to 14.8 [10.3-18.8] mg/L, p = 0.88) but increased significantly in Group 2 (16.9 [10.0-21.5] to 19.2 [11.3-29.1] mg/L, p = 0.002), with significant differences between the groups in absolute and percentage terms (p = 0.015 and 0.019, respectively). Changes in CRP and SAA, both absolute and percentage, were significantly correlated in Group 2 (r = 0.60 and 0.66, both p < 0.001). The responsiveness of plasma SAA to an inflammatory stimulus in Group 2 alone suggests a pro-inflammatory status in patients prone to acute coronary syndrome but not in those with inducible myocardial ischemia.