Abstract 2856: Effects of Various Treatments on Aspirin Resistance in Patients Presenting to the Emergency Department with Chest Pain: Preliminary Results of the Aspirin Resistance Testing and Initial Strategy for Treatment (ARTIST) Multicenter Trial
Introduction: In the setting of a suspected acute coronary syndrome (ACS), aspirin (ASA) is the primary treatment used for platelet inhibition. However, recent studies have demonstrated that up to 20% of patients do not respond to ASA therapy. The ARTIST trial tested whether treatment of ASA resistance with either higher doses of ASA or additional antiplatelet agents would improve responsiveness to platelet inhibition.
Methods: We enrolled 647 patients at 5 centers who presented to the emergency department (ED) with a chief complaint of chest pain and who were either on outpatient ASA therapy or received ASA in the ED. ASA resistance was tested using the VerifyNow® (Accumetrics) device. Patients who exhibited ASA resistance, defined as aspirin resistance units (ARU) ≥550, were randomized to receive one of four therapies: additional ASA 325 mg, clopidogrel 300 mg or 600 mg, or standard therapy (no additional ASA or clopidogrel). ARU were measured at baseline, 2 hours, and 6–8 hours post-treatment. Changes in ARU values for each treatment arm were calculated.
Results: Changes in ARU values differed significantly between the four treatment arms (p<0.007), with the greatest reduction in ARU seen in patients who received additional ASA (Figure 1⇓). The mean ARU values in the ASA treatment arm were 631 at baseline, 440 at 2 hours, and 450 at 6–8 hours. There was no significant difference among the four arms with respect to amount of ASA taken before treatment, the duration of outpatient ASA therapy or baseline ARU.
Conclusions: In ASA resistant patients presenting to the ED with a suspected ACS, additional ASA appears to be an effective treatment for ASA resistance.