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Angiotensin-converting enzyme inhibitors increase vasoconstrictor requirements after cardiopulmonary bypass
K J Tuman1, R J McCarthy, C J O'Connor
1Department of Anesthesiology, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612.
Insights
Preoperative angiotensin-converting enzyme (ACE) inhibitor use increases the need for vasoconstrictor therapy after cardiopulmonary bypass (CPB). This highlights a significant risk factor for hypotension in cardiac surgery patients.
Area of Science:
- Cardiovascular Surgery
- Anesthesiology
- Pharmacology
Background:
- Preoperative angiotensin-converting enzyme (ACE) inhibitor use is common in patients undergoing cardiac surgery.
- ACE inhibitors have been linked to hypotension following cardiopulmonary bypass (CPB).
Purpose of the Study:
- To prospectively examine the influence of chronic preoperative ACE inhibitor use on the incidence of vasoconstrictor therapy needed after CPB.
- To identify perioperative factors contributing to hypotension despite adequate cardiac output post-CPB.
Main Methods:
- Prospective study of 4301 adult patients undergoing elective coronary artery and/or valve surgery.
- Analysis of patients receiving ACE inhibitors versus those not, focusing on the need for vasoconstrictor infusions post-CPB.
- Logistic regression to identify independent risk factors for requiring vasoconstrictor therapy.
Main Results:
- 7.7% of ACE inhibitor patients required at least two vasoconstrictor infusions post-CPB compared to 4.0% of non-users (P = 0.0001).
- ACE-inhibited patients showed lower systemic vascular resistance post-CPB (6.4% vs 2.8%, P = 0.0002).
- Independent risk factors included ACE inhibitor use, heart failure, poor LV function, CPB duration, reoperation, age, and opioid anesthesia.
Conclusions:
- Preoperative ACE inhibitor use is an independent risk factor for requiring vasoconstrictor therapy after CPB in cardiac surgery.
- This association persists despite adequate cardiac output, suggesting altered vascular tone.
- Careful consideration of ACE inhibitor management is warranted in the perioperative period for cardiac surgery patients.
Abstract:
Preoperative use of angiotensin-converting enzyme (ACE) inhibitors is common and has been associated with hypotension at separation from cardiopulmonary bypass (CPB). This study prospectively examined the influence of chronic preoperative ACE inhibitor use and other perioperative factors on the incidence of vasoconstrictor therapy required to maintain systolic blood pressure at more than 85 mm Hg despite a normal cardiac output after CPB in 4301 adults undergoing elective coronary artery and/or valve surgery. Hypothermic, nonpulsatile CPB and either opioid or ketamine-benzodiazepine anesthesia were common features of the operations. At least two vasoconstrictor infusions (phenylephrine, norepinephrine, or dopamine) were required for low perfusion pressure despite adequate cardiac output after CPB in 7.7% of 519 ACE-inhibited patients and 4.0% of 3782 patients not receiving ACE inhibitors (P = 0.0001). In the first 4 h after arrival in the intensive care unit, the need for vasoconstrictor infusions to treat hypotension with adequate cardiac output did not differ, although more ACE-inhibited patients (6.4%) exhibited low values of systemic vascular resistance (< 600 dyne.s.cm-5) than patients not receiving ACE inhibitors (2.8%; P = 0.0002). Logistic regression analysis identified preoperative ACE inhibitor use, congestive heart failure, poor left ventricular function, duration of CPB, reoperative surgery, age, and opioid anesthesia as independent risk factors for requiring > or = 2 vasoconstrictor infusions after CPB. No other preoperative drug therapy significantly altered this outcome.