Diabetes mellitus and carotid artery plaques exhibiting high-intensity signals on MR angiography are related to increased platelet reactivity after carotid artery stenting

BACKGROUND: Increased platelet reactivity after carotid artery stenting (CAS) may cause thromboembolic complications. OBJECTIVE: This study aimed to investigate the incidence of increased platelet reactivity after CAS and to determine the factors related to it. METHODS: Patients who underwent CAS were recruited prospectively. They received pre-procedural antiplatelet therapy comprising some combination of aspirin (100 mg/day), clopidogrel (75 mg/day), and/or cilostazol (200 mg/day) for a minimum of 7 days. ADP- and collagen-induced platelet aggregation were measured before and 4 days after CAS. Changes in platelet reactivity were reported as changes in the categorized platelet reactivity grade based on the effective dose 50%. Clinical characteristics of patients with and without increased platelet reactivity were compared. RESULTS: Among 38 consecutive patients who underwent CAS, 18 (47%) exhibited increased platelet reactivity. Diabetes mellitus (OR 15.0; 95% CI 2.1 to 106.5; p=0.007) and carotid artery plaques exhibiting high-intensity signals (HIS) on time-of-flight MR angiography (TOF-MRA) (OR 25.2; 95% CI 2.0 to 316.2; p=0.013) were independently associated with increased platelet reactivity in a multivariate analysis. CONCLUSIONS: Increased platelet reactivity occurred in nearly half of the studied patients subjected to CAS and was independently associated with diabetes mellitus and carotid artery plaques exhibiting HIS on TOF-MRA.