Chronic Angiotensin Converting Enzyme Inhibitors in Intermediate Risk Surgery

Overview

Primary research hypothesis: Patients who continue their chronic ACEI therapy up to and including the morning of a non-cardiac, non-vascular surgery will experience more intraoperative hypotension than those who transiently hold their chronic ACEI preoperatively. Secondary research hypothesis #1: Patients who continue their chronic ACEI up to and including the morning of a non-cardiac, non-vascular surgery will experience better postoperative control of hypertension than those who transiently hold their chronic ACEI preoperatively. Secondary research hypothesis #2: Patients who continue their chronic ACEI up to and including the morning of a non-cardiac, non-vascular surgery will experience less acute renal failure than those who transiently hold their chronic ACEI preoperatively. Secondary research hypothesis #3: In the subgroup of patients with a preoperative systolic blood pressure less than 110 mmHg, those who continue their chronic ACEI therapy up to and including the morning of a non-cardiac, non-vascular surgery will experience more intraoperative hypotension than those who transiently hold their chronic ACEI preoperatively. Secondary research hypothesis #4: In the subgroup of patients above the age of 64, those who continue their chronic ACEI therapy up to and including the morning of a non-cardiac, non-vascular surgery will experience more intraoperative hypotension than those who transiently hold their chronic ACEI preoperatively.

The purpose of this study is to determine if transient discontinuation of angiotensin converting enzyme inhibitors (ACEIs) is necessary prior to non-cardiac, non-vascular surgery. ACEIs have been associated with intraoperative hypotension during vascular and cardiac surgeries. Patients presenting to the University of Nebraska Medical Center Pre-Anesthesia Screening (PAS) Clinic who are on chronic ACEI therapy will be eligible for enrollment. Subjects will be randomized to either omit or continue their ACEI preoperatively. The outcome of interest is intraoperative hypotension defined as a systolic blood pressure less than 80 mmHg. Blood pressure will be followed not only throughout surgery, but also during recovery and the remainder of hospitalization. Renal function will be assessed with creatinine measurements in the PAS clinic and on the first postoperative day. No follow-up is planned beyond discharge from the hospital.