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Updated: Jul 5, 2026
A Chronic Cardiac Ischemia Model in Swine Using an Ameroid Constrictor
Published on: October 9, 2017
Cardiac ischemia model for +Gz using miniature swine and baboons
John W Burns1, William B Kruyer, Paul V Celio
1Biosciences and Protection Division, Air Force Research Laboratory Brooks City-Base, TX, USA. john.burns@amedd.army.mil
Background:
Military aircrew with minimal coronary artery disease (MCAD) may be restricted from flying high-performance aircraft due to possible ischemia during high +Gz. An animal model is presented to provide ischemia data for a more informed decision.
Methods:
There were 18 swine that were placed on a high cholesterol/high fat diet for up to 57 wk. Five control swine were maintained on a standard swine diet. Also, nine male baboons had a constrictor placed around the left anterior descending coronary artery. Two baboons were sham-operated controls. The unanesthetized swine and baboons were infused with Tc-99m at the end of +Gz exposure and scanned for myocardial perfusion.
Results:
Five swine died unexpectedly before +Gz exposure with moderate-to-severe CAD. Dysrhythmias during +Gz were seen equally in both the control and experimental swine and in the baboons before and after stenosis, with or without propranolol. During +Gz, ECG ST-T wave changes suggesting ischemia were observed in the cholesterol swine but not the control swine, and in the baboons before and after stenosis, with or without propranolol. There was a positive relationship between a normal/abnormal ECG and a normal/abnormal myocardial perfusion scan in the swine and a weak relationship in the baboon before stenosis, but somewhat better after stenosis. Coronary histopathology showed normal vessels from the control swine and stenoses ranging from 0-95% from the cholesterol swine. Baboon stenosis averaged 37.6 +/- 15.0%.
Conclusions:
In the swine and the baboon extended high levels of +Gz, were associated with evidence of myocardial ischemia.
