The Evolving Concept of Dual Antiplatelet Therapy after Percutaneous Coronary Intervention: Focus on Unique Feature of East Asian and "Asian Paradox"

Abstract

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor is essential after percutaneous coronary intervention (PCI), while many studies have focused on determining the optimal degree of platelet inhibition and optimal DAPT duration to minimize complications after PCI. Current guidelines developed by the American College of Cardiology/American Heart Association and the European Society of Cardiology summarize previous studies and provide recommendations. However, these guidelines are mainly based on Western patients, and their characteristics might differ from those of East Asian patients. Previous data suggested that East Asian patients have unique features with regard to the response to antiplatelet agents. On comparing Western and East Asian patients, it was found that East Asian patients have a lower rate of ischemic events and higher rate of bleeding events after PCI, despite a higher on-treatment platelet reactivity, which is referred to as the "East Asian paradox." As the main purpose of DAPT is to minimize ischemic and bleeding complications after PCI, these differences should be clarified before adopting the guidelines for East Asian patients. Therefore, in this article, we will review various issues regarding DAPT in East Asian patients, with a focus on the unique characteristics of East Asian patients, previous studies regarding antiplatelet agents in East Asian patients, and a guideline from an East Asian perspective.

Keywords: Bleeding risk; Dual antiplatelet therapy; East Asians; Ischemic risk; Percutaneous coronary intervention.

Figure 1. Mechanism of clopidogrel activation and representative candidate genes involved each step.

CYP = cytochrome P450.

Figure 2. Ischemic and bleeding events according to prolonged versus short DAPT in East Asians and Westerners. Absolute frequency of ischemic events was half in Asians than Caucasians, while incidence of bleeding was 2-times in Asians than Caucasians. Prolonged DAPT failed to reduce ischemic events in both Asians and Caucasians, while increased bleeding events, remarkably in East Asian patients. This figure was modified from the original version.

DAPT = dual antiplatelet therapy.

Figure 3. Results from a retrospective analysis of a nationwide cohort of Korean AMI patients. During a 1-year follow-up period after index PCI, ischemic outcomes and bleeding outcomes were analyzed. Compared with clopidogrel (AC), new generation P2Y12 receptor inhibitors prasugrel (AP) and ticagrelor (AT) could not decrease ischemic outcomes, while significantly increased bleeding outcomes. Consistent results were shown in multivariate cox regression analysis, propensity score matching analysis, inverse probability weighted regression analysis, and pooled analysis after multiple imputation. This figure was modified from the original version.

AMI = acute myocardial infarction; CI = confidence interval; DAPT = dual antiplatelet therapy; HR = hazard ratio; MACCE = major adverse cardiac and cerebral events; PCI = percutaneous coronary intervention.