How soon before cardiac surgery should aspirin be stopped?

Aspirin irreversibly inhibits platelet function by blocking the cyclooxygenase pathway. It is a vital adjunct in the prevention of coronary thrombosis1 and is known to reduce the risk of acute bypass graft closure.2 Unfortunately it also causes increased bleeding after cardiac surgery and increases the risk of emergency re-sternotomy in the first few hours.3 For this reason many centres try to stop aspirin for a few days prior to surgery.

Platelets have a life span in the plasma of approximately 10 days. Therefore if aspirin were discontinued 10 days prior to surgery, the affected platelet pool would be completely replenished with fresh platelets by the time of the operation. This however leaves the patient vulnerable to an acute myocardial event during the latter part of this time and may also make graft occlusion more likely in the immediate postoperative period. It also supposes that operating lists can be planned 10 days in advance.

In reality, patients are usually asked to stop aspirin 5–7 days in advance. This seems to be a suitable compromise for the majority of patients although for a few (tight left main stem stenosis or past history of TIAs or stroke), the risk of stopping aspirin may outweigh the potential benefits.