Inflammatory bowel disease (IBD) is a relatively common disease that effects all age groups and carries significant morbidity and mortality. The initial treatment typically involves both short and long term medication, however when this is not enough to adequately control the disease, surgery is often required. The high morbidity and mortality rates are in part due to the increased rates of venous thromboembolism (VTE) such as deep vein thrombosis (DVT) or pulmonary embolism (PE) which have been shown to develop more frequently in IBD patients compared to the general population. Undergoing abdominal surgery has also been shown to independently increase rates of DVT and PE and since the majority of patients with IBD will undergo surgery at least once in their lifetime, the relative increased risk of developing a VTE is very high. The majority of DVT and PE events in the postoperative IBD population will occur after discharge from hospital and therefore carries significant morbidity and mortality risk in a unmonitored setting. Several studies have demonstrated the benefits and safety of twice daily dosing of oral extended VTE prophylaxis agents in orthopedic and cancer postoperative patients following discharge from hospital. There have been no randomized studies which have evaluated the use of extended postoperative VTE prophylaxis in IBD patients. The purpose of this randomized placebo controlled pilot trial will be to evaluate the efficacy and safety of postoperative VTE prophylaxis in IBD patients following abdominal surgery. If this pilot trial demonstrates efficacy in reducing postoperative DVT and PE rates, safety and feasibility, clinicians will be armed with the knowledge to pursue a larger multicenter randomized trial with the intent of reducing overall morbidity and mortality in this high risk population.

Inclusion Criteria:

• >18 years old
• Having documented pathological diagnosis of either Crohn's disease or ulcerative colitis.
• Open or laparoscopic abdominal gastrointestinal surgery
• Elective surgery
• Surgery occurring at Hamilton Health Sciences or St. Joseph's Healthcare Hamilton
• Negative urine beta-hCG for women of childbearing potential

Exclusion Criteria:

• Contraindication to use of postoperative thromboprophylaxis (ie. Previous bleeding on anticoagulation)

• Allergy to apixaban

• History of VTE

• Current clinically significant active bleeding, including GI bleeding

• Hepatic disease associated with coagulopathy and clinically relevant bleeding risk

• Severe renal impairment (eCrCl <30 ml/min), or undergoing dialysis

• Lesions or conditions at increased risk of clinically significant bleeding (e.g. recent GI bleeding, recent ischemic or hemorrhagic cerebral infarction, active ulcerative GI disease, recent brain, spinal or ophthalmological surgery, bronchiectasis or history of pulmonary bleeding, thrombocytopenia or functional platelet defects, congenital or acquired coagulation disorder)

• Receiving any of the following drugs:

  • Strong inhibitors of both CYP 3A4 and P-gp, such as azole-antimycotics (e.g. ketoconazole, itraconazole, voriconazole, or posaconazole), and HIV protease inhibitors (e.g. ritonavir)
  • Strong inducers of both CYP 3A4 and P-gp (e.g. rifampicin, phenytoin, carbamazepine, phenobarbital, or St. John's Wort)
  • Drug products affecting hemostasis (e.g. NSAIDs, ASA or other antiplatelet agents [e.g. ASA, clopidogrel, prasugrel, ticagrelor], SSRIs, or SNRIs)
  • Any other anticoagulant, including unfractionated heparin, LMWH, heparin derivatives, or oral anticoagulants (e.g. warfarin, dabigatran, rivaroxaban)

• Currently receiving therapy for any type of malignancy (e.g. colorectal, breast, lung)

• History of colorectal cancer

• Emergency surgery

• Patients with an indication for anticoagulation before surgery (atrial fibrillation, etc.)

• Enrolled in any other clinical trials or prospective studies where similar outcomes are measured

• Pregnant (i.e. positive pregnancy test and/or self-reported) and/or breastfeeding

• Women of childbearing potential unwilling/unable to participate in appropriate family planning during the treatment period

This study will not share any individual participant data with other researchers.