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Myocardial protection by continuous coronary perfusion during aortic valve replacement
Insights
This study details a cardiac surgery method for myocardial protection during aortic valve replacement using physiological coronary perfusion. Maintaining adequate coronary perfusion pressure and utilizing larger cannulae proved crucial for preventing ischemic injury.
Area of Science:
- Cardiovascular Surgery
- Cardiothoracic Anesthesia
- Cardiac Physiology
Background:
- Myocardial protection is critical during aortic valve replacement (AVR).
- Ischemic injury can occur if coronary perfusion is inadequate.
- Optimizing coronary perfusion strategies is essential for patient outcomes.
Purpose of the Study:
- To describe the coronary perfusion system at Oulu University Central Hospital.
- To emphasize the importance of physiological coronary perfusion in preventing myocardial ischemic injury during AVR.
- To present a method for myocardial protection during AVR.
Main Methods:
- Phasic constant-pressure coronary perfusion was employed.
- Coronary perfusion pressure was maintained at or above 80 mmHg.
- The heart was kept in a beating, empty, oxygenated state, using the largest feasible coronary cannula.
Main Results:
- The described method maintained autoregulation of the coronary vascular bed.
- Smaller coronary cannulae resulted in significant pressure drops, particularly at high flow rates.
- On-line electromagnetic flowmeter measurements were reliable for monitoring flow.
Conclusions:
- The presented coronary perfusion strategy effectively protects the myocardium from ischemic injury during AVR.
- Adequate coronary perfusion pressure and appropriate cannula size are vital for maintaining physiological flow.
- The method ensures reliable monitoring of coronary blood flow.
Abstract:
The coronary perfusion system used at Oulu University Central Hospital is described and the importance of physiological coronary perfusion stressed. Our method of protecting the myocardium from ischemic injury during aortic valve replacement included the following: phasic constant-pressure coronary perfusion, maintenance of coronary perfusion pressure larger than or equal to 80 mmHg, maintenance of the heart in a beating, empty, oxygenated state, and the use of the largest possible coronary canula. Under these circumstances, autoregulation of the coronary vascular bed was maintained. When small coronary cannulae were used a significant pressure drop occured across the tubing system, especially at high flow rates. Flow measurements recorded by an on-line electromagnetic flowmeter proved reliable.