Article Text
Abstract
Objective: To evaluate residual platelet activity in a consecutive cohort of patients treated with dual antiplatelet therapy after coronary stent implantation
Design: Prospective single centre cohort study.
Setting: University hospital in Germany. Patients: 480 patients with symptomatic coronary artery disease (n=221 (46%) acute coronary syndrome, ACS; n=259 (54%) stable angina, SAP). Platelet activity was measured by collagen (5µg/ml)- and ADP (20µmol/L)-induced platelet aggregation to assess post-treatment activity in patients treated with ASA (500 mg bolus i.v. followed by 100 mg o.d.) and clopidogrel (600 mg loading dose followed by 75 mg o.d.)
Main outcome measures: Increased residual platelet activity (IRPA) was defined if platelet aggregation was in the upper tertial of values in the patient collective. Association of epidemiological factors with IRPA were evaluated in a multivariate logistic regression analysis.
Results: IRPA-ADP was found in 53 patients (11.0%) and IRPA-collagen in 42 patients (8.8%). ACS was associated with IRPA independently from other factors (for IRPA-collagen: odds ratio (OR): 2.3, 95% confidence interval (CI): 1.2 - 4.5, P<0.05; for IRPA-ADP: OR: 2.4 ; 95%CI: 1.3 to 4.4; P<0.01; for IRPA-ADP/collagen: OR: 4.5, 95%CI: 1.2-16.9; P<0.05).
Conclusions: In a large unselected cohort of patients we assessed post-treatment platelet sensitivity to agonist stimulation. The data suggest that ACS is independently associated with increased residual platelet activity despite conventional antiplatelet therapy. Further studies are warranted to demonstrate effects of an intensified antiplatelet therapy for patients with acute coronary events.
- acute coronary syndrome
- aggregation
- aspirin resistance
- clopidogrel resistance
- platelets