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Glutamate-blood cardioplegia improves ATP preservation in human myocardium
O I Pisarenko1, V F Portnoy, I M Studneva
1USSR Cardiology Research Center, Moscow.
Insights
Adding glutamic acid to blood cardioplegic perfusate enhances myocardial protection during cardiac arrest. This method helps preserve adenosine triphosphate (ATP) levels, crucial for heart muscle function after surgery.
Area of Science:
- Cardiology
- Cardiovascular Surgery
- Biochemistry
Background:
- Myocardial protection during cardiac arrest is critical for patients undergoing complex heart surgeries.
- Maintaining adenosine triphosphate (ATP) levels is essential for preserving heart muscle function during ischemia.
- The role of specific substrates in cardioplegic solutions for myocardial preservation requires further investigation.
Purpose of the Study:
- To investigate the efficacy of glutamic acid-enriched blood cardioplegic perfusate in preserving myocardial ATP levels.
- To compare the effects of standard cardioplegia versus glutamic acid-supplemented cardioplegia on myocardial energy metabolism.
- To evaluate the impact of glutamic acid on glutamate and lactate levels in myocardial tissue during cardiac arrest.
Main Methods:
- A prospective study involving two groups of patients undergoing radical correction of Fallot's tetrad and ventricular septal defects.
- Control group received standard cold blood potassium cardioplegic solution.
- Experimental group received cardioplegic perfusate supplemented with glutamic acid (20 mmol/l).
- Left ventricular biopsies were obtained pre- and post-aortic cross-clamping to measure ATP, glutamate, and lactate.
- Average aortic cross-clamping time was 32 minutes for both groups.
Main Results:
- In the control group, ATP loss correlated with decreased glutamate levels during cardiac arrest.
- The glutamic acid-enriched perfusate maintained higher myocardial glutamate content, preventing ATP decline or increasing ATP levels.
- No significant differences in lactate levels were observed between the groups post-cardiac arrest.
- Glutamic acid supplementation demonstrated a protective effect on myocardial energy stores.
Conclusions:
- Enrichment of blood cardioplegic solution with glutamic acid offers superior myocardial protection during ischemic heart arrest.
- Glutamic acid may serve as a substrate for anaerobic energy production, thereby enhancing myocardial ATP preservation.
- This strategy represents a promising advancement in cardioplegic solutions for cardiac surgery.
Abstract:
Two groups of patients subjected to radical correction of Fallot's tetrad and defects of interventricular septum were investigated to ascertain whether the addition of glutamic acid to blood cardioplegic perfusate could improve preservation of myocardial ATP during cardiac arrest. In the control group (17 patients) the myocardial protection was performed by repeated infusions of cold blood potassium cardioplegic solution; in the 2nd group (24 patients) cardioplegic perfusate containing glutamic acid (20 mmol/l) was used. Left ventricular biopsies were taken during the first minute after cross-clamping of the aorta and before the release of the aortic clamp to determine ATP, glutamate and lactate. The cross-clamping time averaged 32 min in both groups. In the patients of the control group the losses of ATP correlated with the decrease in glutamate during the clamping period. A maintenance of a higher myocardial glutamate content by glutamate-containing cardioplegic perfusate prevented ATP fall or increased its level in patients of the 2nd group. There was no significant difference in lactate levels between the two groups by the end of the cardiac arrest. We conclude that enrichment of blood cardioplegic solution by glutamic acid, which may act as a substrate for anaerobic energy production, provides more effective myocardial protection during ischemic heart arrest.