Abstract 4019: Efficacy and Safety of Double Dosage of Clopidogrel in AMI Patients with Low Response to Clopidogrel Undergoing Delayed PCI
Background: Clopidogrel resistance is associated with increased risk of recurrent athero-thrombotic events in patients with acute myocardial infarction. This study was to assess the efficacy and safety of double dosage clopidogrel in STEAMI patients undergoing delayed PCI with low response to clopidogrel (LRC).
Methods: A total of 132 AMI patients with LRC were enrolled into this study. LRC was defined as less than 30% reduction in platelet aggregation rate (PAR) 12 hours after 300mg oral clopidogrel. All patients were randomly divided into standard dose group (SDG, n=67) and double dosage group (DDG, n=65). Patients in SDG received 75mg clopidogrel per day, while patients in DDG received 150mg clopidogrel. PAR at baseline, 7 days after the therapy were measured and its changes (ΔPAR) were calculated. The corrective TIMI frame count (CTFC), TMP grade (TMPG) after PCI were recorded. All patients were followed up for 10 days, the hemorrhage events and MACEs were collected.
RESULT: The baseline PAR were not different between the two groups (63.63±6.74 vs 64.54±5.51, p>0.05). At the seventh day, PAR in DDG was lower than SDG (36.33±3.49 vs 40.19±6.21, p>0.05). ΔPAR was larger in DDG than that in SDG (34.11±4.50 vs 24.21±5.96, p<0.05). CTFC in DDG was smaller than SDG (28.37±4.68 vs 30.29±4.54, P<0.05), the percent of TMPG>2 was larger in DDG than SDG (75.00% vs 53.57%, P<0.05). Acute intra-stent thrombosis were found in 8 patients in SDG whereas this was not found in DDG (P<0.05). Mild hemorrhage was found in 3 patients in SDG and 4 in DDG (P>0.05). No death, recurrent infarction and hemorrhage needing transfusion were found in the two groups.
Conclusion: To STEAMI patients with LRC, the double dosage clopidegrel might effectively inhibit platelet aggregation, improve coronary blood flow and myocardium perfusion, and prevent from the intra-stent thrombosis without increased hemorrhage and MACEs.