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Biochemical indicators of myocardial ischaemia during coronary artery bypass grafting
S Kaukinen1, T Metsä-Ketelä, L Kaukinen
1Department of Anaesthesia, Tampere University Central Hospital, Finland.
Insights
Myocardial catecholamine release, not lactate, is the most sensitive indicator of heart muscle damage during coronary artery bypass grafting (CABG). This finding is crucial for monitoring patient safety during cardiac surgery.
Area of Science:
- Cardiology
- Biochemistry
- Cardiac Surgery
Background:
- Myocardial ischemia during cardiac surgery can lead to perioperative infarction.
- Accurate monitoring of myocardial viability is crucial during coronary artery bypass grafting (CABG).
- Existing metabolic indicators may not fully capture myocardial stress during cardiopulmonary bypass (CPB).
Purpose of the Study:
- To evaluate metabolic indicators of myocardial ischemia in patients undergoing CABG.
- To compare the sensitivity of lactate and catecholamine release as markers of myocardial injury during CPB.
- To investigate the correlation between myocardial metabolic changes and perioperative infarction.
Main Methods:
- Blood samples were collected from the coronary sinus and arterial blood in six CABG patients.
- Samples were analyzed before, during, and after cardiopulmonary bypass (CPB).
- Measurements included lactate, adenosine, inosine, hypoxanthine, noradrenaline, and adrenaline levels.
Main Results:
- Myocardial lactate production was common during CPB but not before.
- Adenosine, inosine, and hypoxanthine release did not correlate with lactate production.
- Myocardial catecholamine (noradrenaline and adrenaline) release correlated with lactate levels and was elevated in patients with myocardial infarction.
Conclusions:
- Myocardial catecholamine release is a more sensitive biochemical indicator of myocardial ischemia during CABG than lactate.
- Elevated catecholamine production during CABG indicates significant myocardial stress and potential injury.
- Monitoring myocardial catecholamine release may improve perioperative patient management during cardiac surgery.
Abstract:
Metabolic indicators of myocardial ischaemia were measured in coronary sinus blood in six patients undergoing coronary artery bypass grafting (CABG). Five arterial and coronary sinus blood samples were taken in each case--one before cardiopulmonary bypass (CPB), and three during and one after CPB. Moderate hypothermia with topical cardiac cooling and cold cardioplegia were used. Myocardial infarction occurred perioperatively in two patients. Myocardial lactate production was not found before CPB in any patient, but it was common during CPB. Adenosine, inosine and hypoxanthine were released into the coronary sinus blood, but their release did not correlate significantly with lactate production. Myocardial noradrenaline production showed positive correlation with lactate levels (p less than 0.05). Release of adrenaline from the myocardium during CABG was also demonstrated. Myocardial catecholamine production was especially seen in the patients with myocardial infarction. Myocardial catecholamine release seemed to be the most sensitive of the studied biochemical indicators of myocardial ischaemia during CABG.