Aspirin found to prevent heart attacks after non-cardiac surgery in patients with prior coronary intervention

Study shows that for every 1,000 patients, aspirin prevents 59 heart attacks but causes eight major bleeding events.

A Canadian-led study has found that aspirin given just before, during and shortly after major non-cardiac surgery can prevent heart-related complications in patients who had a previous percutaneous coronary intervention (PCI) such as an angioplasty or stent.

"This is your next-door neighbour who had angioplasty five years ago, feels fine and needs to go in for hip surgery. It affects quite a large number of people," said the study's lead author, Michelle Graham, an interventional cardiologist and professor in the University of Alberta's Department of Medicine. She said 200 million adults around the world undergo major non-cardiac surgery annually.

The study showed that for every 1,000 patients with PCI, giving them aspirin at the time of non-cardiac surgery would prevent 59 heart attacks and cause eight major bleeding events.

These results were a substudy of POISE-2, a large international study with sites in 135 centres, including Edmonton, in 23 countries. Patients with previous PCI were enrolled in 82 centres in 21 countries.

Non-cardiac surgeries occur daily at hospitals around the world, so the study results will have a big impact on this patient group.

In patients without a PCI, POISE-2 showed that aspirin did not reduce the risk of heart attack and led to an increased risk of major bleeding.

Of the 10,010 participants enrolled in the POISE-2 study, 470 had a previous PCI. Because patients with a prior PCI have an increased risk of cardiovascular complications after non-cardiac surgery, the group wanted to see whether the findings were the same in the subgroup.

This was the largest randomized trial of patients with PCI undergoing major non-cardiac surgery. Although aspirin reduced the risk of heart attack among patients in the study, it also slightly increased the risk of bleeding, though that risk did not appear worse than in the overall POISE-2 trial.

"There will be a big knowledge translation push with our colleagues in anesthesia and surgery to remind them that we want them to continue to give aspirin to this group of patients, when for most other groups we're recommending they stop," said Graham.

The Canadian Cardiovascular Society guidelines published last year indicated that aspirin should not be given in the perioperative period-the time frame from hospital admission and surgery through to recovery.

"This will potentially change the practice of anyone who does perioperative medicine," said Graham.

The study, "Aspirin in Patients with Previous Percutaneous Coronary Intervention Undergoing Noncardiac Surgery," was published Nov. 14 in Annals of Internal Medicine.

Funding for the Canadian study was largely provided by the Canadian Institutes of Health Research.