TY - JOUR
T1 - Profile and prevalence of clopidogrel resistance in patients of acute coronary syndrome
AU - Kumar, Sandeep
AU - Saran, Ram K.
AU - Puri, Aniket
AU - Gupta, Nishant
AU - Sethi, Rishi
AU - Surin, W. R.
AU - Dikshit, Madhu
AU - Dwivedi, Sudhanshu K.
AU - Narain, Varun S.
AU - Puri, Vijay K.
PY - 2007
Y1 - 2007
N2 - Recently reports of a variable platelet response to aspirin and potential resistance to therapy have emerged with thienopyridines group of drugs. However the data available on clopidogrel resistance is scarce. The present study was initiated to prospectively evaluate the prevalence of clopidogrel resistance in patients of acute coronary syndrome (ACS) presently on dual anti platelet therapy by using an established method of optical platelet aggregation. We studied 39 patients of ACS, who were on clopidogrel 300 mg bolus followed by 75 mg per day for 3 days along with aspirin 325 mg per day. Fasting blood samples were assessed using optical platelet aggregation (Chronolog Corp, USA). Clopidogrel resistance was defined as <10% decrease from baseline in platelet aggregation. Clopidogrel semi-responders were defined as 10-29% (<30%) decrease from baseline in platelet aggregation. Clopidogrel non-responders were defined as a composite of resistant and semi-responders. A baseline mean platelet aggregation obtained from 18 healthy subjects was 63.8 ± 14.75% with 5 μM and 68.8 ± 13.91% with 10 μM of Adenosine Diphosphate. Hence, the definition of clopidogrel resistance was set as aggregation of >57% with 5 μm ADP and >61.9% with 10 μm ADP (<10% decrease from baseline). The definition of clopidogrel semi-responder was set as aggregation of 45% with 5 μm ADP and 48% with 10 μm ADP (10-29% decrease from baseline). The mean platelet aggregation with 5 μM and 10 μM of Adenosine Diphosphate in the patient group was 30.77 ± 17.19% and 35.71 ± 17.0% respectively. Based on these criteria, 2.54% patients were found to be clopidogrel resistant, 12.7% were clopidogrel semi-responders and 84.7% were clopidogrel responders. On comparison of clopidogrel responders with non-responders, females (p = 0.07) and patients with higher serum triglyceride levels (p = 0.08), had a trend to be more inclined towards clopidogrel non-responders. All other parameters tested namely age, smoking, diabetes, hypertension, obesity, cholesterol, hemoglobin, platelet count, ejection fraction and concurrent drug intake did not show any statistically significant difference among the groups. CONCLUSIONS This study shows that clopidogrel resistant and clopidogrel semi-responders do occur in Indian patients with ACS and there are no reliable clinical predictors for this condition. The diagnosis therefore relies primarily on laboratory tests.
AB - Recently reports of a variable platelet response to aspirin and potential resistance to therapy have emerged with thienopyridines group of drugs. However the data available on clopidogrel resistance is scarce. The present study was initiated to prospectively evaluate the prevalence of clopidogrel resistance in patients of acute coronary syndrome (ACS) presently on dual anti platelet therapy by using an established method of optical platelet aggregation. We studied 39 patients of ACS, who were on clopidogrel 300 mg bolus followed by 75 mg per day for 3 days along with aspirin 325 mg per day. Fasting blood samples were assessed using optical platelet aggregation (Chronolog Corp, USA). Clopidogrel resistance was defined as <10% decrease from baseline in platelet aggregation. Clopidogrel semi-responders were defined as 10-29% (<30%) decrease from baseline in platelet aggregation. Clopidogrel non-responders were defined as a composite of resistant and semi-responders. A baseline mean platelet aggregation obtained from 18 healthy subjects was 63.8 ± 14.75% with 5 μM and 68.8 ± 13.91% with 10 μM of Adenosine Diphosphate. Hence, the definition of clopidogrel resistance was set as aggregation of >57% with 5 μm ADP and >61.9% with 10 μm ADP (<10% decrease from baseline). The definition of clopidogrel semi-responder was set as aggregation of 45% with 5 μm ADP and 48% with 10 μm ADP (10-29% decrease from baseline). The mean platelet aggregation with 5 μM and 10 μM of Adenosine Diphosphate in the patient group was 30.77 ± 17.19% and 35.71 ± 17.0% respectively. Based on these criteria, 2.54% patients were found to be clopidogrel resistant, 12.7% were clopidogrel semi-responders and 84.7% were clopidogrel responders. On comparison of clopidogrel responders with non-responders, females (p = 0.07) and patients with higher serum triglyceride levels (p = 0.08), had a trend to be more inclined towards clopidogrel non-responders. All other parameters tested namely age, smoking, diabetes, hypertension, obesity, cholesterol, hemoglobin, platelet count, ejection fraction and concurrent drug intake did not show any statistically significant difference among the groups. CONCLUSIONS This study shows that clopidogrel resistant and clopidogrel semi-responders do occur in Indian patients with ACS and there are no reliable clinical predictors for this condition. The diagnosis therefore relies primarily on laboratory tests.
KW - Acute coronary syndrome
KW - Clopidogrel resistance
KW - Platelet aggregation
UR - http://www.scopus.com/inward/record.url?scp=37849053346&partnerID=8YFLogxK
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C2 - 19122249
AN - SCOPUS:37849053346
SN - 0019-4832
VL - 59
SP - 152
EP - 156
JO - Indian Heart Journal
JF - Indian Heart Journal
IS - 2
ER -