TIMING
OF ASPIRIN ADMINISTRATION AS A DETERMINANT OF SURVIVAL OF PATIENTS WITH ACUTE
MYOCARDIAL INFARCTION TREATED WITH THROMBOLYSIS
Freimark
D, et al. Am J Cardiol 2002 Feb 15;89(4):381-5.
BACKGROUND:
Unlike thrombolytic agents, there are conflicting data regarding the
time-dependent effect of aspirin treatment on outcome in acute myocardial
infarction (AMI). We sought to evaluate the impact of timing of aspirin
administration (before vs after thrombolysis) on mortality of patients with
AMI.
METHODS:
Our study included 1,200 patients with ST elevation AMI treated with thrombolysis.
Early (n = 364) versus late (n = 836) users were defined as those receiving
emergency aspirin before versus after initiation of thrombolysis, respectively.
RESULTS:
Time (median) from symptom onset to initiation of aspirin treatment was significantly
shorter in early versus late users (1.6 vs 3.5 hours; p <0.001). There were
no significant differences between the 2 groups with respect to baseline
clinical characteristics. Early aspirin users were more likely to develop
reischemia, to be treated with beta blockers, to be referred to coronary
angiography, percutaneous transluminal coronary angioplasty, or coronary artery
bypass graft surgery. Early users experienced lower mortality at 7 days (2.5%
vs 6.0%, p = 0.01), 30 days (3.3% vs 7.3%, p = 0.008), and 1 year (5.0% vs
10.6%, p = 0.002) than late users. This survival benefit persisted for patients
with and without previous aspirin therapy or revascularization and after
adjustment for baseline characteristics and therapies at 7 days (odds ratio 0.36,
95% confidence interval 0.15 to 0.79), at 30 days (odds ratio 0.39, 95%
confidence interval 0.17 to 0.82), and at 1 year (odds ratio 0.41, 95%
confidence interval 0.21 to 0.74).
CONCLUSION:
Our study proposes a time-dependent benefit from aspirin in patients with AMI
treated with thrombolysis.
COMMENTS:
While this is an interesting study, the results may be circumstantial as early
ASA users also got early beta-blockers and more aggressive therapy. However, it should be noted that there is no
reason not to give aspirin to patients with possible ACS symptoms short of a
history of anaphylactic reaction from aspirin.