A Canadian-led study has found that peri-operative aspirin can prevent heart-related complications after major non-cardiac surgery in patients with previous percutaneous coronary intervention (PCI) such as an angioplasty or stent.
The study found 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. The results of this study are significant, given that 200m adults undergo major non-cardiac surgery annually.
These results were a sub-study of POISE-2, a large international study with sites in 135 centres in 23 countries, including Edmonton. 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. "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 Michelle Graham, an interventional cardiologist, professor in the University of Alberta's department of medicine and lead of the sub-study. "We believe that peri-operative aspirin in this group of patients will most likely benefit them and reduce their risk of serious vascular complications."
In patients without a PCI, POISE-2 found 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, 470 had a previous PCI. Since patients with a prior PCI have an increased risk of cardiovascular complications after non-cardiac surgery, the group wanted to see if the findings were the same in the sub-group.
This was the largest randomised trial of patients with PCI undergoing major non-cardiac surgery. Although the study found that aspirin reduced the risk of heart attack, it did slightly increase the risk of bleeding, though it did not appear worse than in the overall POISE-2 trial.
"There will be a big knowledge translation push with our colleagues in anaesthesia and surgery to remind them we want them to continue aspirin in this group of patients, when for most other groups we're recommending they stop," says Graham.
The Canadian Cardiovascular Society guidelines published last year indicated that aspirin should not be given in the peri-operative period. "This will potentially change the practice of anyone who does peri-operative medicine," said Graham.
Graham recognises that studies like this are not possible without the participation of patients. "We could not advance the field of medicine without the patients that participate in trials like POISE-2," said Graham. "This really is a team sport, we need the surgeons, anaesthesiologist and patients on board to make it successful."
Funding for this study were largely provided by the Canadian Institutes of Health Research.
Background: Uncertainty remains about the effects of aspirin in patients with prior percutaneous coronary intervention (PCI) having noncardiac surgery.
Objective: To evaluate benefits and harms of perioperative aspirin in patients with prior PCI.
Design: Nonprespecified subgroup analysis of a multicenter factorial trial. Computerized Internet randomization was done between 2010 and 2013. Patients, clinicians, data collectors, and outcome adjudicators were blinded to treatment assignment.
Setting: 135 centers in 23 countries.
Patients: Adults aged 45 years or older who had or were at risk for atherosclerotic disease and were having noncardiac surgery. Exclusions were placement of a bare-metal stent within 6 weeks, placement of a drug-eluting stent within 1 year, or receipt of nonstudy aspirin within 72 hours before surgery.
Intervention: Aspirin therapy (overall trial, n = 4998; subgroup, n = 234) or placebo (overall trial, n = 5012; subgroup, n = 236) initiated within 4 hours before surgery and continued throughout the perioperative period. Of the 470 subgroup patients, 99.9% completed follow-up.
Measurements: The 30-day primary outcome was death or nonfatal myocardial infarction; bleeding was a secondary outcome.
Results: In patients with prior PCI, aspirin reduced the risk for the primary outcome (absolute risk reduction, 5.5% [95% CI, 0.4% to 10.5%]; hazard ratio [HR], 0.50 [CI, 0.26 to 0.95]; P for interaction = 0.036) and for myocardial infarction (absolute risk reduction, 5.9% [CI, 1.0% to 10.8%]; HR, 0.44 [CI, 0.22 to 0.87]; P for interaction = 0.021). The effect on the composite of major and life-threatening bleeding in patients with prior PCI was uncertain (absolute risk increase, 1.3% [CI, -2.6% to 5.2%]). In the overall population, aspirin increased the risk for major bleeding (absolute risk increase, 0.8% [CI, 0.1% to 1.6%]; HR, 1.22 [CI, 1.01 to 1.48]; P for interaction = 0.50).
Limitation: Nonprespecified subgroup analysis with small sample.
Conclusion: Perioperative aspirin may be more likely to benefit rather than harm patients with prior PCI.
Graham MM, Sessler DI, Parlow JL, Biccard BM, Guyatt G, Leslie K, Chan MTV, Meyhoff CS, Xavier D, Sigamani A, Kumar PA, Mrkobrada M, Cook DJ, Tandon V, Alvarez-Garcia J, Villar JC, Painter TW, Landoni G, Fleischmann E, Lamy A, Whitlock R, Le Manach Y, Aphang-Lam M, Cata JP, Gao P, Terblanche NCS, Ramana PV, Jamieson KA, Bessissow A, Mendoza GR, Ramirez S, Diemunsch PA, Yusuf S, Devereaux PJ