Abstract 20850: Impact of Self-Reported Ethnicity on Response to Clopidogrel in Patients Underoing Percutaneous Coronary Intervention
Background: Several studies have shown substantial inter-individual variability in response to clopidogrel following percutaneous coronary intervention with stenting (PCI-S). This might reflect differences in clinical, demographic and genetic parameters, which differ by ethnicity. Data evaluating ethnic differences in platelet reactivity are limited, however, as most studies included racially homogoneous or Caucasian cohorts. Accordingly, we sought to determine differences in response to clopidogrel by ethnicity in patients undergoing PCI-S.
Methods: We studied 164 patients on chronic clopidogrel (75 mg/day) who underwent platelet function testing after a 300-mg clopidogrel load at the time of PCI-S between January 1, 2009 and April 30, 2010. Response to clopidogrel was defined as residual platelet reactivity (RPR) to adenosine diphosphate using the VerifyNow P2Y12 Analyzer and expressed as P2Y12 Reaction Units (PRU). High residual platelet reactivity (HRPR) was defined as PRU values ≥ 240. Based on self-report, patients were categorized as Caucasian, African-American, Hispanic and South Asian (Pakistani, Indian, Nepalese and Bangladeshi descent).
Results: Mean PRU values among Caucasians (n=82), African-Americans (n=17), Hispanics (n-23) and South Asians (n=42) were 182 ± 98, 182 ± 118, 271 ± 85 and 262 ± 96 (p < .001). Analagously, the frequencies of HRPR were 28%, 29%, 65% and 64%, respectively (Figure, p = .003). Compared to Caucasians, the multivariable adjusted odds ratios (OR) for HRPR associated with African-American, Hispanic and South Asian ethnicity was 1.3 (95% CI: 0.3 - 4.8), 7.3 (95% CI: 2.2 - 24.3), and 4.6 (95% CI: 1.8 - 11.8), respectively. Results were similar after excluding patients with diabetes.
Conclusion: Response to clopidogrel, as determined by RPR to adenosine diphosphate, varies by ethnicity. Further investigation is warranted to identify mechanisms of increased platelet reactivity in Hispanic and South Asian patients.
- © 2010 by American Heart Association, Inc.