Indirect comparison meta-analysis of aspirin therapy after coronary surgery.
OBJECTIVE
To evaluate the efficacy of low and medium dose aspirin therapy after coronary surgery by using an indirect comparison meta-analysis.


METHODS
Systematic literature search of Medline, Embase, Cochrane controlled trials register, and trial register sites on the internet.


METHODS
Outcome was evaluated by angiography and reported as graft occlusion and rate of events in patients. Trials that did not include aspirin as the sole therapy or did not have a placebo control arm were excluded. Articles were assessed for eligibility and quality and grouped according to dosage. The estimated difference in effect of low and medium dose aspirin on graft occlusion was obtained by combining the estimated log relative risks of low dose with placebo and medium dose with placebo.


RESULTS
For graft occlusion, the medium dose trials yielded a relative risk reduction of 45% compared with 26% for the low dose trials. The greater effect in the medium dose trials is summarised by a relative risk ratio of 0.74 (95% confidence interval 0.52 to 1.06; P = 0.10) for graft occlusion and 0.81 (0.57 to 1.16; P = 0.25) for events in patients.


CONCLUSIONS
Medium dose aspirin may more successfully reduce graft occlusion than low dose regimens within the first year after coronary surgery.
Lim
Eric
E
Department of Cardiothoracic Surgery, Papworth Hospital, Cambridge CB3 8RE. eric.lim2@cvsnet.org
Ali
Ziad
Z
Ali
Ayyaz
A
Routledge
Tom
T
Edmonds
Lyn
L
Altman
Douglas G
DG
Large
Stephen
S
D001241:Aspirin / Q000008:administration & dosage*; D019917:Blood Vessel Prosthesis Implantation; D003327:Coronary Disease / Q000601:surgery*; D006083:Graft Occlusion, Vascular / Q000517:prevention & control*; D006801:Humans; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D011182:Postoperative Care / Q000379:methods; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors
D010975:Platelet Aggregation Inhibitors; D001241:Aspirin