Angiotensin II concentrations and gut mucosal perfusion in infants undergoing cardiopulmonary bypass

J Cardiothorac Vasc Anesth. 1999 Aug;13(4):446-50. doi: 10.1016/s1053-0770(99)90218-5.


Objectives: To determine whether hypothermic cardiopulmonary bypass (CPB) per se causes an increase in angiotensin II (A-II) concentration in infants and to investigate the relationship between A-II concentration and gut mucosal perfusion.

Design: Prospective, open, nonrandomized, observational study.

Setting: Children's teaching hospital.

Participants: Thirty acyanotic infants requiring CPB.

Interventions: A-II concentrations were measured on six occasions before, during, and after CPB. An orogastric tonometer allowed intermittent calculations of gastric intramucosal pH (pHi). Gastric mucosal blood flow (flux) was monitored using a laser Doppler flowmeter. Ten infants acted as controls (group 1); 10 infants received captopril, 0.9 mg/kg orally, 45 minutes before induction of anesthesia (group 2), and 10 infants received enalaprilat, 0.06 mg/kg intravenously, just before CPB (group 3).

Measurements and main results: A-II concentrations were abnormally high in 28 of 30 patients before CPB (median, 450 pg/mL (range, 83 to 5,787 pg/mL). A-II concentrations in groups 1 and 2 decreased during CPB, but values remained at twice normal levels throughout surgery (median, 171 to 198 pg/mL post-CPB). A-II concentrations remained normal (range, 52 to 120 pg/mL) during and after CPB in patients receiving enalaprilat (group 3). The authors found no significant correlation between A-II concentration and pHi or flux before, during, or after surgery.

Conclusions: Acyanotic infants requiring cardiac surgery may have high perioperative concentrations of A-II. Hypothermic CPB is associated with a decrease in A-II concentration. Reductions in gut mucosal perfusion seen in some infants during hypothermic CPB are not related to increases in A-II concentrations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin II / blood*
  • Angiotensin-Converting Enzyme Inhibitors / therapeutic use
  • Blood Pressure
  • Captopril / therapeutic use
  • Cardiac Surgical Procedures
  • Cardiopulmonary Bypass*
  • Enalaprilat / therapeutic use
  • Gastric Mucosa / blood supply*
  • Gastric Mucosa / metabolism
  • Humans
  • Hydrogen-Ion Concentration
  • Infant
  • Laser-Doppler Flowmetry
  • Prospective Studies
  • Regional Blood Flow


  • Angiotensin-Converting Enzyme Inhibitors
  • Angiotensin II
  • Captopril
  • Enalaprilat