Clinical Outcomes Of High Loading Dose Clopidogrel Pretreatment Before Percutaneous Coronary Interventions

Objective: To compare the short-term efficiency and safety of high loading dose(600mg) clopidogreal pretreatment with those of routine loading dose(300mg)before the procedure in patients undergoing percutaneous coronary intervention.Methods: A total of 100 patients scheduled to undergo percutaneous coronaryintervention between November 2005 to June 2006 were randomly seperated to a600mg (n=50) or 300mg (n=50) loading regimen of clopidogrel before the procedure.The adenosine diphosphate (ADP)-induced max platelet aggregation rate (MPAR)were measured at baseline and at 16 and 36 hours after administration of clopidogrel.The incidence of major clinical cardiovascular event(including death, myocardialinfarction, target vessel revascularization, stroke ) and hemorrhagic events werefollowed up to 30 day and 6 month.Results: The baseline clinical and angiographic characteristics and the result ofstenting were similar in both groups. At 16 hours after administration of clopidogrel,600 mg group produced greater inhibition of ADP (5umol/L and 20 umol/L)induced max platelet aggregation than 300mg group[ADP 5umol/L: (21.83±18.04)％vs(14.79±k9.18)％, p=0.034, ADP 20umol/L: (22.12±14.81)％vs (15.67±10.15)％, p=0.039]. At 36 hours after administration of clopidogrel, the reduction of ADP(5umol/Land 20 umol /L) induced- aggregation of the two groups was [ADP 5umol/L:(16.70±15.42)％vs (12.94±10.34)％, p= 0.11] and [20umol/L: (14.14±13.16)vs(10.19±k9.49)％, p= 0.073]. The incidenc of 30 day and 6 month major clinicalcardiovascular event in 600rag group were significantly less than that in 300 mg group (14％vs 32％, p=0.032; 30.9％vs 68.2％, p=0.001). The occurrence of 30 day and6 month hemorrhagic events between the two groups had no significant difference (44％vs 34％, p=0.31; 57.1％vs 40.9％, p=0.13).Conclusions: Pretreatment with a 600mg loading dose of clopidogrel before theprocedure is more efficient in inhibiting platelet aggregation and, compared with theconventional 300-rag dose, significantly improve Clinical outcomes in patientsundergoing percutaneous coronary intervention.