Research reveals aspirin is safe for heart surgery patients

A worldwide study led by Monash University clinician-researchers shows that patients who take aspirin before heart surgery are at no greater risk of bleeding or complications. 

Published 25 February in the New England Journal of Medicine, the collaborative research study led by Professor Paul Myles, Head of the Department of Anaesthesia and Perioperative Medicine in the Central Clinical School and Alfred Health, investigated whether stopping or continuing aspirin before coronary artery surgery posed more risks or benefits.

Most patients with coronary artery disease receive aspirin for prevention of heart attack, stroke, and death. However aspirin poses a bleeding risk for patients undergoing surgery, and prior to this study it was unclear whether aspirin should be stopped before coronary artery surgery.

Professor Myles said until recently, ceasing aspirin five to seven days before surgery has been traditional practice in most cardiac surgical centres.

"Until now, conflicting guidelines from expert professional organisations highlight the lack of evidence to determine if the increased risk of surgical bleeding could be outweighed by a beneficial effect of aspirin," said Professor Myles.

Study co-author and Head of Surgery at the School of Clinical Sciences at Monash HealthProfessor Julian Smith said "The study found the use of aspirin, as compared with placebo, before coronary artery surgery did not reduce the risk of death and thrombotic complications.

"Preoperative aspirin exposure did not increase surgical bleeding, transfusion requirements or need for re-operation and there is therefore no reason to stop aspirin before coronary artery surgery," Professor Smith added.

The researchers evaluated the benefits and bleeding risks of aspirin at a dose of 100mg, the dose deemed to have the strongest evidence of efficacy balanced against a low risk of bleeding complications.

"We wanted to determine whether it was best to stop or continue aspirin in patients undergoing heart surgery because the blood-thinning (or anti-coagulant) properties of aspirin are well-established," said co-author and Head of School of Public Health and Preventive Medicine Professor John McNeil.

"Stopping aspirin five to seven days before surgery increases thrombotic risk before the benefits of bypass grafting can be achieved and sometimes surgery is cancelled or delayed exposing the patient to increased thrombotic risk," added Professor Myles.  

"Withdrawal of aspirin in patients scheduled for surgery to reduce bleeding risk could be harmful."

2100 patients across five countries in 19 participating hospitals were enrolled and randomly assigned to the research project.