Preoperative aspirin does increase risk of perioperative bleeding

EDITOR—In Sonksen et al's editorial on safer non-cardiac surgery for patients with coronary artery disease the authors say that they considered that aspirin does not increase perioperative bleeding.1 We were astonished to read this. They based the statement on studies of aspirin's mechanism of action in vitro and the preoperative use of the bleeding time.

The bleeding time correlates poorly with other tests of platelet function and is a poor predictor of bleeding.2 The editorial states that aspirin has no effect on platelet aggregation induced by thrombin and high dose collagen. This statement is based only on a study that used flow cytometry. In other studies, laboratory tests of platelet function have shown impaired platelet activity induced by collagen and thrombin after aspirin.3 4 Impaired platelet function in vitro has been documented for more than 72 hours after ingestion of aspirin.

In vitro studies are not predictive of in vivo behaviour, and several clinical studies have clearly shown that aspirin does increase bleeding in both cardiac and non-cardiac surgery.3 5 For prostate surgery the withdrawal of aspirin for at least a week preoperatively …