The Effect of Discontinuation of Renin Angiotensin System Inhibitors on the Perioperative Myocardial Injury in Adult Patients Undergoing Colorectal Cancer Surgery

Inclusion Criteria: * Age \> 18 years * Both sexes * ASA 2-3 * Chronic hypertensive patients (\> 3 months before surgery) controlled on ACEIs or ARBs or combination therapy containing one of the RAS inhibitors. * Scheduled for major abdominal cancer surgery (surgery with an expected duration of \> 2 h from the surgical incision and a postoperative hospital stay of least three days). Exclusion Criteria: * Patient refusal. * Recent myocardial infarction (within 3 months). * Any condition, which in the opinion of the treating clinician, would result in the patient being harmed by the cessation of the ACE-I and/or ARB therapy. * Emergency surgery