Stent thrombosis is a common complication of PCI with stent implantation and is associated with STEMI [
1,
2]. Patients with STEMI, who have been treated with stent implantation, are commonly treated with dual antiplatelet therapy (DAPT), such as clopidogrel and acetylsalicylic acid, to prevent atherothrombotic complications [
2]. Worldwide, there are over 3 million people who suffer from STEMI every year [
3]. The prodrug clopidogrel is converted into its active metabolite by Cytochrome P2C19 (CYP2C19) in the liver [
4]. The P2Y12 receptors on platelets are inhibited by the active metabolites, which consequently leads to inhibition of platelet aggregation. Until recently, clopidogrel was the standard P2Y12 receptor inhibitor used to treat these patients. However, approximately 26% of the Saudi population carry polymorphisms in the
CYP2C19 gene which leads to the production of an inactive enzyme [
5]. Patients with a
CYP2C19*2 LoF allele are unable to activate clopidogrel, as evidenced in numerous reports on drug platelet reactivity assays [
6]. Studies have shown that patients who carry
CYP2C19*2 LoF alleles have a higher risk of developing atherothrombotic complications after stent implantation compared to non-carriers [
7,
8].
During the last decade two novel antiplatelet drugs, namely prasugrel and ticagrelor, have come onto the market for clinical use [
9]. Similar to clopidogrel, prasugrel irreversibly inhibits the P2Y12 receptor. However, unlike clopidogrel, prasugrel does not require bioactivation by the
CYP2C19 allele to act as an inhibitor of platelet aggregation [
10,
11]. Moreover, ticagrelor, which is not a prodrug, directly inhibits the P2Y12 receptor [
12]. There are some advantages for patients who are prescribed prasugrel and ticagrelor in that there is no interpatient variation of effectiveness and these drugs are faster-acting, which is especially important for patients with acute STEMI [
13]. It has been shown that there is a significant decrease in the mortality rate in patients treated with ticagrelor compared to those patients who are treated with clopidogrel. Moreover, the influence of CYP2C19 on the action of these drugs is minimal [
14]. However, clopidogrel remains the anti-platelet pharmaceutical of choice in Saudi Arabia due to its considerably lower cost and availability. In Saudi Arabia, it has been reported that approximately 26% of the population carries CYP2C19*2 and/or *3 loss-of-function polymorphisms in addition to a high prevalence of cardiovascular disease [
15‐
21]. The primary and secondary objectives of the trial are shown below: