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[Anoxic myocardial lesions in man, developed during extracorporeal circulation, studied by electron microscopy]
Abstract:
Anoxemic changes of the myocardium were examined at 20 patients operated on in extracorporal circulation. At a mild degree hypothermia (30 degrees C) morphological changes appear after a 20 minutes period of anoxaemia. Damage to the myocard of irreversible character could be revealed after an anoxaemic period of 43--55 minutes. An intermitting perfusion of the coronary arteries delayes the formation of the lesions, although in cases of ligation of the aorta for 90 minutes severe mitochondrial changes and deformation of cells were seen. The best method for protecting the myocard is an isotherm perfusion of the coronary arteries. Clinical and laboratory findings show that necrosis of the myocard has a focal character and may play a part in formation of postoperative lesions.
Insights
Myocardial changes during extracorporeal circulation were studied. Mild hypothermia and anoxaemia cause damage, with irreversible changes after 43-55 minutes. Isothermic coronary perfusion offers the best myocardial protection.
Area of Science:
- Cardiovascular Surgery
- Cardiology
- Pathology
Background:
- Extracorporeal circulation (ECC) is vital for cardiac surgery.
- Understanding myocardial response to anoxaemia during ECC is crucial for patient outcomes.
- Hypothermia and perfusion strategies impact myocardial protection.
Purpose of the Study:
- To investigate anoxemic changes in the myocardium during ECC.
- To determine the timeline of reversible and irreversible myocardial damage.
- To evaluate the efficacy of different perfusion techniques for myocardial protection.
Main Methods:
- Examination of myocardial tissue from 20 patients undergoing ECC.
- Assessment of morphological changes under mild hypothermia (30°C).
- Evaluation of intermittent versus isothermic coronary artery perfusion.
Main Results:
- Morphological changes observed after 20 minutes of anoxaemia at 30°C.
- Irreversible myocardial damage noted after 43–55 minutes of anoxaemia.
- Intermittent perfusion delayed lesions, but 90 minutes of aortic ligation caused severe mitochondrial and cellular damage.
- Isothermic coronary artery perfusion demonstrated the most effective myocardial protection.
Conclusions:
- Myocardial necrosis is focal and can contribute to postoperative lesions.
- The duration of anoxaemia and perfusion strategy significantly influence myocardial injury.
- Isothermic coronary artery perfusion is the optimal method for protecting the myocardium during ECC.