Chronic Angiotensin Converting Enzyme Inhibitors in Intermediate Risk Surgery

Phase 4

Completed

Brief Summary: 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.

Detailed Description: 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.

Recruitment & Eligibility

Inclusion Criteria

Referred to the University of Nebraska Medical Center Pre-Anesthesia Screening Clinic for preoperative evaluation.
Above referral must be in anticipation of a non-cardiac, non-vascular surgery.
Must have been on ACE-Inhibitor therapy for at least six weeks.

Exclusion Criteria

Hypotension (systolic blood pressure < 90 or diastolic blood pressure <60) at the time of preoperative evaluation
Uncontrolled Hypertension (systolic blood pressure > 150 or diastolic blood pressure > 95) at the time of preoperative evaluation
Surgery during which vasopressor use is anticipated (carotid endarterectomy, major abdominal operations, orthopedic oncology)
Surgery for pathology related to vasoactive substances (carcinoid, pheochromocytoma)
Left Ventricular ejection fraction less than 40%
Clinical evidence of decompensated heart failure at the time of preoperative evaluation
End-stage renal disease
Organ transplant surgeries

Arm && Interventions

Group	Intervention	Description
ACEI omission	ACEI omission	Patients randomized to this arm will be told to omit their final preoperative chronic angiotensin converting enzyme inhibitor dose.
ACEI continuation	ACEI continuation	Patients in this arm will be randomized to continue their chronic angiotensin converting enzyme inhibitor without interruption preoperatively

Primary Outcome Measures

Name	Time	Method
Number of Participants With Interoperative Hypotension	During anesthesia, an expected average of 3 hours.	Number of Participants with Interoperative Hypotension (systolic blood pressure under 80 mmHg)

Secondary Outcome Measures

Name	Time	Method
Acute Renal Failure	Arrival in post-anesthesia care unit (PACU) to hospital discharge, an expected average of 4 days.	Creatinine increase of more than 0.3 mg/dl or more than 50% from preoperative level
Older Age Subgroup	During anesthesia, an expected average of 3 hours.	Only patients above the age of 64 will be included in this analysis. The outcome is the same as the primary outcome: Intraoperative Systolic Blood Pressure under 80 mmHg
Postoperative Hypertension	Arrival in PACU to hospital discharge, an expected average of 4 days.	Any systolic blood pressure greater than 180 mmHg.
Low Blood Pressure Subgroup	During anesthesia, an expected average of 3 hours.	Only patients with systolic blood pressure less than 110 at preoperative evaluation will be included in this analysis. The outcome is the same as the primary outcome: Intraoperative Systolic Blood Pressure under 80 mmHg.
Postoperative Hypotension	Arrival in PACU to hospital discharge, an expected average of 4 days.	Any systolic blood pressure less than 90 mmHg