I don’t understand the design of this study. Arms a) and c) are described in terms of the anticoagulation prophylaxis, while arm b) is described in terms of the anesthesia, which would seem to be a separate issue. Arm b) is also the only arm to contain an antiplatelet drug (aspirin).
If the objective of this retrospective study was to see if dirt-cheap aspirin works as well as more expensive therapies, there ought to be completed RCT’s that provide the answer.
“The efficient-market hypothesis may be
the foremost piece of B.S. ever promulgated
in any area of human knowledge!”