Comparison of the effects of alternate-day aspirin 81 mg and daily aspirin 162 mg on in-hospital cardiovascular events after myocardial infarction: An open-label, controlled, randomized clinical trial

Yasue, Hirofumi MD
Ogawa, Hisao MD
Tanaka, Hiromitsu MD
Miyazaki, Shunichi MD
Hattori, Ryuichi MD
Saito, Muneyasu MD
Ishikawa, Kinji MD
Masuda, Yoshiaki MD
Yamaguchi, Tetsu MD
Motomiya, Takeshi MD
Tamura, Yoshiyuki MD

Kumamoto, Kagoshima, Osaka, Kyoto, Saitama, Chiba, Tokyo, and Kagawa, Japan
From the ^aDepartment of Cardiovascular Medicine, Kumamoto University School of Medicine.^BFaculty of Medicine and University Hospital, Kagoshima University.^CNational Cardiovascular Center, Osaka.^DDivision of Emergency Medicine, Kyoto University School of Medicine.^EOmiya Medical Center, Jichi Medical School, Saitama.^FFirst Department of Medicine, Kinki University School of Medicine, Osaka; the ^gThird Department of Internal Medicine, Chiba University School of Medicine.^HThe Third Department of Internal Medicine, Ohashi Hospital Toho University School of Medicine, Tokyo.^IDepartment of Cardiology, Hiroo General Hospital, Tokyo; and ^jDepartment of Cardiology, Zentsuji National Hospital, Kagawa.

Supported by a Research Grant for Cardiovascular Disease (6A-1) from the Japanese Ministry of Health and Welfare, Tokyo, Japan.

*A full list of the JAMIS investigators and participating centers appears in the Appendix.

Submitted December 1, 1998.

Accepted November 23, 1999.

Reprint requests: Hirofumi Yasue, MD, Department of Cardiovascular Medicine, Kumamoto University School of Medicine, 1-1-1 Honjo, Kumamoto City 860-8556, Japan. E-mail:

[email protected]

American Heart Journal 139(5):p e10-e15, May 2000.

Background

It has been well-established that aspirin therapy reduces the risk of vascular events in the acute phase of evolving acute myocardial infarction (AMI). However, the adequate dose of aspirin for AMI has not yet been determined.

Methods

To compare alternate-day aspirin 81 mg and daily aspirin 162 mg on the effects of in-hospital cardiovascular events after AMI, we performed a multicenter, open-label, controlled, randomized clinical trial. The aspirin regimen was started immediately, with 162 mg on the first and second day, and randomly allocated to alternate-day aspirin 81 mg and162 mg aspirin daily after the third day and continued in the hospital. Three hundred sixty-five patients with AMI were allocated to alternate-day aspirin 81 mg and 386 patients with AMI to daily aspirin 162 mg.

Results

The observation period was 29.9 ± 0.6 days. There were no statistically significant differences between the 2 treatment groups in age, sex, hours from onset to admission, Killip classification, number of thrombolytic therapies, percutaneous transluminal coronary angioplasty, and other drugs (nitrates, calcium antagonists, β-blockers, and angiotensin-converting enzyme inhibitors). There were also no differences between the 2 groups in the incidence of refractory angina to drug therapy, reinfarction, cerebral vascular accidents, and occurrence of side effects. However, cardiac death occurred in 9 patients in the daily aspirin 162 mg group but in none of those in the alternate-day aspirin 81 mg group (P = .0037). On the other hand, fatal cerebral infarction occurred in 2 patients in the alternate-day 81 mg aspirin group but in none of those in the daily aspirin 162 mg group.

Conclusions

We conclude that this study, although underpowered to show meaningful differences in outcome, did not show any difference in in-hospital cardiovascular events with alternate-day aspirin 81 mg compared with daily aspirin 162 mg. (Am Heart J 2000;139:e4.)