C-reactive protein levels increase after exercise testing in patients with increased platelet reactivity.

Aspirin has the potential to influence C-reactive protein (CRP) levels, an inflammatory marker, by its anti-inflammatory activity. Persistently increased platelet reactivity, however, can be detected with different laboratory methods despite aspirin therapy in some patients. The aim of this study was to investigate the effects of increased platelet reactivity on CRP levels at rest and after exercise in patients with documented or suspected coronary artery disease. Blood samples were collected from 100 patients (age, 58.1+/-8.5 years; 63.0% men) who were treated with 100 or 300 mg/day enteric-coated aspirin for at least 7 days, before and immediately after treadmill test for CRP analyses. Platelet reactivity was measured by the standardized platelet function analyzer-100, and increased platelet reactivity was defined as a normal collagen/epinephrine closure time (<165 s). Of the 100 patients, 82 had normal platelet reactivity (group A) and 18 had increased platelet reactivity (group B). The CRP levels increase was statistically significant after exercise in patients with increased platelet reactivity [group A: 2.3 (1.4-4.3) to 2.8 (1.6-4.9) mg/l, P=0.09; group B: 3.3 (2.0-4.5) to 4.7 (2.9-8.5) mg/l, P=0.02]. Detecting increased platelet reactivity is associated with an increase in CRP levels. The clinical significance of this finding needs to be further investigated.