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A calf model for left ventricular centrifugal mechanical assist
F A Mann1, C C Wagner-Mann, J J Curtis
1Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, USA.
Artificial Organs
|June 1, 1996
Summary
This study developed a calf model for testing centrifugal mechanical assist (CMA) devices in postcardiotomy cardiogenic shock. Thromboembolism occurred in 51% of calves, highlighting a key challenge for CMA research.
Area of Science:
- Cardiovascular Surgery
- Biomedical Engineering
- Animal Models
Background:
- Refractory postcardiotomy cardiogenic shock necessitates advanced treatments like centrifugal mechanical assist (CMA).
- Improving clinical outcomes requires robust experimental models for subchronic testing of CMA devices.
Purpose of the Study:
- To describe and validate a calf model for in vivo subchronic testing of left ventricular centrifugal mechanical assist.
Main Methods:
- Holstein bull calves (n=35) underwent instrumentation for left ventricular CMA, with 4 serving as sham controls.
- Preoperative conditioning, anesthesia, surgical techniques, and postoperative management in a specialized crate were standardized.
- Calves were monitored for 96 hours, followed by postmortem examination.
Main Results:
- 51% of calves developed thromboembolism, primarily in the lumbar spinal cord, leading to paresis/paralysis.
- Complications included intraoperative ventricular fibrillation, hemothorax, cannula dislodgement, and feeding-associated tachycardia.
- No surgical or distant infections were found; cannulae were secure except in one case; no thrombus formed at cannulation sites.
Conclusions:
- The calf model provides a platform for subchronic CMA testing but requires addressing the high incidence of thromboembolism.
- Younger calves showed better conditioning and tolerance to postoperative restraint.
- Thromboembolic lesion incidence was not linked to sedation, tachycardia, or atrioventricular block.