Changes in D-dimer and inflammatory biomarkers before ischemic events in patients with peripheral artery disease: The...

Whether circulating biomarker levels increase shortly before an ischemic heart disease (IHD) event is unknown. We studied whether levels of D-dimer, C-reactive protein (CRP), and serum amyloid A (SAA) are higher within 2 months of an IHD event compared to time periods more than 2 months before the IHD event. We assembled 595 participants with peripheral artery disease (PAD) and followed them for up to 3 years. Blood samples were obtained every 2 months. The primary outcome was IHD events: myocardial infarctions, unstable angina, or IHD death. We used a nested case-control design. Fifty participants (cases) had events and were each matched by age, sex, duration in the study, and number of blood draws to two controls without events. Among cases, the mean D-dimer value of 1.105 obtained within 2 months of the event was higher than values obtained 10 months (0.68 mg/L, p<0.001), 12 months (0.71 mg/L, p=0.001), 16 months (0.65 mg/L, p=0.008), 20 months (p=0.032), 22 months (p=0.033), 26 months (p=0.038), and 32 months (p=0.04) before the event. Compared to controls, median D-dimer levels in cases were higher 4 months (p=0.017), 6 months (p=0.005), and 8 months (p=0.028) before the event. Values of CRP and SAA obtained within two months of an IHD event not consistently higher than values obtained during the prior months. In PAD participants with an IHD event, D-dimer was higher within 2 months of the event, compared to most values obtained 10 to 32 months previously. D-dimer was also higher in cases as compared to controls during most visits within 8 months of the IHD event.