Abstract
Introduction: Inflammation plays a critical role in coronary artery disease (CAD) and acute myocardial infarction (AMI). Although inflammation, commonly measured by high-sensitivity C-reactive protein (hs-CRP), typically declines after AMI, its precise trajectory compared to stable chest pain cohorts remains unclear. This study assessed hs-CRP levels in stable chest pain patients with and without coronary lesions and in post-AMI patients over time. We hypothesized that hs-CRP would initially be elevated in post-AMI patients, compared to stable chest pain cohorts, and decline over time.
Methods: This study included 257 stable chest pain and 205 post-AMI patients. Stable patients were classified as no-lesion (n=61) or stable CAD (n=195, with lesions) based on coronary computed tomography angiography. Post-AMI patients were enrolled within two months of the event (Visit 1: 28±13 days) and followed at Visit 2 (62±15 days) and Visit 3 (394±23 days); 96 returned for follow-up. Plasma hs-CRP levels and demographic/clinical data were collected. Group differences were analyzed using Kruskal–Wallis and Dunn’s tests, and longitudinal trends with Friedman and mixed-effects linear models. Multivariate adjustments accounted for demographics (age, sex, BMI), CAD risk factors (hypertension, diabetes, hyperlipidemia, smoking, family CAD history), and medication use.
Results: Post-AMI patients had significantly higher hs-CRP levels at Visit 1 (1.43[0.68,3.14] mg/L) compared to no-lesion (0.88[0.35,1.95], p=0.007) and stable CAD (0.84 [0.41,2.11], p<0.001) groups. At Visit 2, hs-CRP (1.40[0.57,2.34] mg/L) remained elevated compared to stable CAD (p=0.022) but was borderline compared to no-lesion (p=0.061). By Visit 3, hs-CRP in post-AMI patients (0.96[0.38,1.55]mg/L) approximated stable cohorts (p>0.05). Longitudinally, hs-CRP declined significantly from Visit 1 to Visit 2 (p=0.038) and Visit 2 to Visit 3 (p<0.001), with the decrease remaining significant after adjustment (Visit 2: β=-2.18±1.00 mg/L, p=0.030; Visit 3: β=-2.35±1.00 mg/L, p=0.019). Cross-sectional differences lost significance after multivariate adjustment (p>0.05).
Conclusions: Post-AMI patients exhibited elevated hs-CRP shortly after AMI, which declined to stable chest pain levels within a year. This reduction remains significant after adjusting for clinical factors, highlighting the dynamic nature of post-AMI inflammation. The loss of cross-sectional significance post-adjustment suggests that hs-CRP reflects both inflammation and underlying patient characteristics.