Clinical effectiveness and safety evaluation for the shift from clopidogrel to ticagrelor in patients with low clopidogrel response

Objective To compare the effectiveness and safety of two switching modalities from clopidogrel to ticagrelor with or without a loading starting dose in patients with low clopidogrel response and acute coronary syndrome(ACS). Methods In this prospective study, 154 ACS patients nonresponsive to clopidogrel were classifi ed at the doctor's discretion to loading dose(ticagrelor starting dose 180 mg, followed by 90 mg bid, n=72) or regular dose group(ticagrelor 90 mg bid, n=82). The primary effi cacy end point was ADP-induced platelet aggregation. The secondary end points were cardiovascular death,myocardial infarction(MI), stroke and the drug adverse events. Results The platelet reactivity of the loading dose group is lower than that of the regular dose group on day 3(17.6±7.2 vs. 25.7±18.3, P=0.008),but non-significant at 30th day. Ticagrelor-related dyspnea was more often in the loading dose group than the regular group(19.4% vs. 12.2%, P=0.001). Most dyspnea instances were mild, ticagrelor was discontinued due to dyspnea in only 2 patients in the loading dose group. No signifi cant difference in therates of bleeding was found between the two starting dose groups. Conclusions In low or non-responders of clopidogrel, compared with a regular maintenance dosage, switching to ticargrelor with a loading dose can achieve rapid early antiplatelet effect, without increased risk of bleeding, but with more mild dyspnea episodes.