TITLE:
Genetic Polymorphisms of ABCB1 Gene in Patients Having Resistance to Clopidogrel
AUTHORS:
R. Madhavi, D. Rajasekhar, P. V. G. K. Sarma, V. Vanajakshamma, G. Sowjenya, K. Sreedhar, C. Kapil
KEYWORDS:
ABCB1, Percutaneous Coronary Intervention, Clopidogrel Resistance, Cardiology
JOURNAL NAME:
World Journal of Cardiovascular Diseases,
Vol.7 No.11,
November
15,
2017
ABSTRACT: Objectives: We sought to study the genetic polymorphisms of ABCB1 gene in post percutaneous coronary intervention (PCI) patients with clopidogrel resistance. Background: Dual antiplatelet therapy (DAPT) is a guideline mandated therapy for patients who undergo PCI. However there exists interindividual variability in drug response to the antiplatelet agents leading to recurrentthrombotic events. Genetic polymorphisms of ABCB1 gene are one among the causes of this interindividual variability. Methods: It is a single center prospective trial and includes221 patients who underwent PCI and were given clopidogrel as a part of DAPT. Platelet reactivity was assessed by grading of platelet activity index (PAI) and considered as high on treatment platelet reactivity (HTPR), i.e., clopidogrel resistance if PAI > 5. Genetic analysis for ABCB1 C-T polymorphism was done by polymerase chain reaction (PCR) and single strand confirmation polymorphism (SSCP) analysis. Results: Amongst 221 patients, 37 (16.7%) patients had ABCB1 C-T polymorphisms. The mean PAI value in these patients was 5.1 ± 3.0, while it was 3.5 ± 2.5 in those patients without ABCB1 C-T polymorphisms (p = 0.004). Compared to patients without HTPR, the occurrence of primary endpoints was not significantly increased in patients with HTPR except for stent thrombosis which was significantly high in patients with HTPR. HTPR was also associated with ABCB1 C-T polymorphisms (p = 0.04), but these polymorphisms did not predict the clinical outcome. Conclusions: There was significant prevalence of ABCB1 C-T polymorphisms in patients with HTPR. However it was not an independent risk factor for clopidogrel resistance and also it did not influence adverse cardiovascular outcomes.