Considerations in patients receiving oral antiplatelet therapy after acute coronary syndrome and percutaneous coronary intervention

Purpose: Adverse events that can occur in patients with acute coronary syndrome (ACS) following percutaneous coronary intervention (PCI), and with the use of oral antiplatelet agents are discussed. Summary: Disruption of the vascular endothelium routinely occurs during PCI and stent placement, resulting in vascular injury. This injury can increase the risk of intracoronary thrombosis and subsequent ACS after PCI. Appropriate antiplatelet therapy reduces the risk of intracoronary thrombosis after PCI; however, health care providers should be aware of the possible limitations associated with specific antiplatelet agents and how to tailor therapy to improve outcomes. Platelet response after a clopidogrel loading dose is highly variable, and platelet hyporesponsiveness to clopidogrel may result in a variety of ischemic complications. A number of methods are available for assessing the antiplatelet effects of clopidogrel. However, none of these tests has been standardized as a measurement for clopidogrel responsiveness. Several polymorphic CYP enzymes are involved in the activation of clopidogrel, and genetic polymorphisms may affect the activity of these enzymes. Genetic variants, particularly the presence of the CYP2C19*2 allele, are associated with poor clinical outcomes after stent placement, along with increased ischemic events in clopidogrel-treated patients. Health care providers should also be aware that drug-drug interactions can occur in patients receiving clopidogrel and other CYP2C19 inhibitors. Conclusion: Prevention and proper management of adverse events can help to optimize outcomes in patients with ACS who have undergone PCI with stent placement.