Effect of Enteric Coating

Effect of Enteric Coating on Antiplatelet Activity of Low-Dose Aspirin in Healthy Volunteers



Effect of Enteric Coating on Antiplatelet Activity of Low-Dose Aspirin in Healthy Volunteers

Introduction

In Western countries, cardiovascular disease accounts for more than 40% of total deaths. Low-dose aspirin is widely used for the prevention and treatment of cardiovascular disease because the antiplatelet therapy with low-dose aspirin (75-325 mg/day) has been reported to be effective in lowering the risk of developing cardiovascular deaths, nonfatal myocardial infarction and stroke in patients with a history of myocardial infarction, unstable angina, nonhemorrhagic stroke or transient ischemic attack.1-3 Furthermore, low-dose aspirin has also been effective in preventing cardiovascular events in a much wider range of patients than previously assumed. These patients include those with peripheral vascular disease, those who underwent coronary angioplasty or coronary bypass grafting4 or high-risk patients for the primary prevention of cardiovascular events. Clopidogrel also further reduces the risk of ischemic events in a broad spectrum of patients when they first present and when they have acute coronary syndrome over the long term. Many studies have reported that antiplatelet agents, such as aspirin, cause mucosal ulceration that can lead to gastrointestinal bleeding.5-9 In addition, combined antiplatelet treatment conferred particular risk and was associated with a high incidence of gastrointestinal bleeding.10 However, controversial opinions exist regarding whether low dose aspirin and/or clopidogrel cause gastrointestinal adverse events. Recently, the population over 60 year-old has rapidly increased along with the prevalence of caroriginal diovascular disease in Korea. Thus, the population of patients that take aspirin and/or clopidogrel, has also quite increased. The prevalence of atrophic gastritis in the Japanese has been reported to be higher than in Western population,11 suggesting that the effect of aspirin or antiplatelet agents in Asians including Koreans could be different from that reported in the West. However, there is limited data on Asians and little information is available on Koreans regarding this issue. Therefore, in this prospective study, we evaluated the safety of low-dose (100 mg) enteric coated aspirin or the combination therapy of aspirin and clopidogrel in patients who underwent coronary angiography.

Materials And Methods

1. Patients In this single-center, prospective, three-arm study pool of 3,620 patients who underwent coronary angiography for evaluation of ischemic heart disease at Seoul National University Bundang Hospital between May 2003 and December 2005, 520 patients were recruited. Exclusion criteria included history of malignancy such as stomach cancer, peptic ulcer, inflammatory bowel disease, antiplatelet medication, gastrointestinal bleeding, liver cirrhosis and esophageal varices. After coronary angiography the patients were allocated to one of three groups; control, acetyl-salicylic acid (ASA) group and ASA+clopidogrel group. The subjects without significant coronary artery stenosis were the control group, and they did not take aspirin or clopidogrel. In the ASA group who had significant coronary artery disease not requiring stent insertion, low-dose enteric coated aspirin was administered at a dose of 100 mg/day. In the ASA+clopidogrel group who had significant coronary artery disease requiring stent insertion, low-dose enteric coated aspirin 100 mg plus clopidogrel 75 ...