Aspirin Continuation or Interruption in Patients at Moderate Risk for Cardiovascular Events Undergoing Colonoscopy and/or Polypectomy; a Placebo-controlled Trial

Aspirin is commonly prescribed to patients for protection against cardiovascular diseases.In 2019, the prevalence of aspirin use was 35.6% in the US. Patients with vascular diseases are at increased risk of having colorectal neoplasms and therefore often undergo screening colonoscopy and possible polypectomy. The management of aspirin before and after colonoscopy and polypectomy has been a contentious subject. The updated British Society of Gastroenterologists (BSG) and ESGE guidelines recommend continuing aspirin except for ESD and EMR > 2cm. The recommendation is based on the low rate of bleeding complications in large cohort studies. In a BSG audit of 20085 colonoscopies in the UK, 52 (0.26%) cases of bleeding were reported. In the English National Bowel Cancer Screening Programme, 69,028 underwent polypectomy.The overall rate of PPB was 1.14% (4). In large series mostly retrospective (> 1000 polypectomies), delayed PPB varied from 0.6 to 2.2 %, and the mean time to onset of bleeding was 4.0 ± 2.9 days (5). The use of aspirin did not emerge to be a factor predicting delayed bleeding. The evidence for continuing aspirin to reduce CV events is conflicting. In an early trial (6) on 220 subjects undergoing non-cardiac surgery, aspirin continuation was associated with a 7.2% risk reduction in postoperative major adverse cardiac events. In the STRATAGEM trial that enrolled 291 patients undergoing general surgery, no difference in thrombotic or bleeding events was observed between groups.The POISE-2 trial was considered the most definitive. It was a placebo-controlled trial that studied patients undergoing again noncardiac surgery, 351 of 4998 patients (7.0%) in the aspirin group and 355 of 5012 patients (7.1%) in the placebo group reached the primary outcome endpoint (death or non-fatal infarcts). Major bleeding was more common in the aspirin group (4.6% vs. 3.8%, P=0.04).Continuation of aspirin was associated with a higher risk of bleeding but did not protect against CV events. There exist variations in clinical practice. A survey of endoscopy centres in the U.S. showed that 44% of endoscopy units recommend continuing aspirin, 33% recommend stopping aspirin and 24% suggest that patients seek advice from a physician. Many endoscopists are concerned about post-polypectomy bleeding and its associated medico-legal risks. In the context of colonoscopy and polypectomy, there has been no randomized comparison between the two strategies of continuing or withholding aspirin. The investigators therefore undertake an RCT to compare cardiovascular and bleeding outcomes in patients undergoing colonoscopy with/without polypectomy. The investigators are planning a large RCT sufficiently powered to detect small differences in these outcomes.