Platelet monitoring for PCI: Is it really necessary?

Percutaneous coronary intervention (PCI) has significantly improved clinical outcomes in coronary artery disease patients. Since PCI is associated with platelet activation, antiplatelet therapy with aspirin, clopidogrel and GPIIb/IIIa inhibitors comprise the cornerstone strategy during and following PCI. The latter agents are arguably the most important drugs we administer to the patient with established coronary artery disease since they are specifically given to prevent the most catastrophic event, the formation of an occlusive arterial thrombus. Numerous clinical trials have confirmed the efficacy of antiplatelet therapy in attenuating recurrent ischaemic event occurrence. Despite the extensive use of antiplatelet therapies, ischaemic event occurrence such as post-procedural myocardial infarction and stent thrombosis still remains an important concern and highlights the need for improved treatment strategies. A major limitation of current treatment is the application of a "one size fits all" strategy advocated by the guidelines that completely ignores the evaluation of the individual antiplatelet response. Pharmacodynamic studies have revealed the limitations of aspirin and clopidogrel treatment that include response variability, and a high prevalence of antiplatelet non-responsiveness associated with significant risk for recurrent ischemic event occurrence. Thus, two major paradoxes in cardiovascular medicine today are: 1) despite the overwhelming evidence that platelet reactivity strongly influences the development of potentially catastrophic events including myocardial infarction and stent thrombosis in the PCI patient, no measurement is made in clinical practice to assess the presence of blood vulnerability (platelet reactivity) and 2) despite the overwhelming evidence that the effect of dual antiplatelet therapy with aspirin and P2Y₁₂ receptor blockers is variable, the guidelines largely recommend a uniform, "one size fits all" dosing of these agents in the PCI patient without any confirmation of an adequate antiplatelet effect.