Genotyping
Frequently occurring genetic polymorphisms tied to aspirin and
clopidogrel resistance were prioritized (detailed in Table 1 ).
Genomic DNA from leukocytes in blood was extracted using the EZNA™ Blood
DNA Midi Kit (Omega Bio-Tek, Norcross, GA, USA). Genotyping was
performed by Boao Biotechnology Co., Ltd (Beijing, China) by MALDI-TOF
mass spectrometry using the MassARRAY system (Sequenom, San Diego, CA,
USA) according to the manufacturer’s instructions. Sequenom Assay Design
3.1 software (Sequenom, San Diego, CA, USA) was used to design
single-base extensions and PCR primers. Genotype calling was performed
in real-time using MassARRAY RT software version 3.0.0.4 and analyzed
using MassARRAY Typer software version 3.4 (Sequenom, San Diego, CA,
USA). The analysis was repeated for quality control on randomly selected
subgroups of 10% of cases and controls; reproducibility was 100%.