The use of Aspirin, and its benefit to Heart patients, was first established by the ISIS-2 Study in 1988 which gave 17,187 patients Aspirin or Placebo, while they were presenting with a heart attack, and showed about a 23% reduction in death by 5 weeks, about the same as was found with Streptokinase, the first clot-dissolver. When given with Streptokinase the reduction went up to 42% It is well known that aspirin benefits patients with Coronary Artery Disease (CAD) but what is the best dose?
For stable patients that dose is 81 mg per day (75 – 81 mg) and it is unnecessary to take more. That recommendation is based on two studies, the CURRENT OASIS 7 trial and the TRANSLATE-ACS Study. In Oasis 7 it was found that the frequency of Cardiac Events was the same, regardless of dose but the risk of bleeding was higher with 325 mg per day. The rate of Cardiac Events was the same even if the patient had a balloon angioplasty and Stent placement.
Similarly in the Translate-ACS study, 10,123 patients were given either 325 mg or 81 mg after a stent when they came into hospital having a heart attack. The rate of death, another heart attack, stroke or needing another procedure was the same whether the patient was on 81 or 325 mg of Aspirin but the bleeding rate was higher on the higher dose of ASA.
Thus, there is no point in going beyond 81 mg as there is no more benefit and the possibility of harm from increased Gastro-intestinal problems and bleeding.