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Comparison of two strategies for myocardial management during coronary artery operations
J R Anderson1, M Hossein-Nia, P Kallis
1Department of Cardiothoracic Surgery, St. George's Hospital Medical School, London, United Kingdom.
Insights
Cold blood cardioplegia resulted in higher creatine kinase MB2 levels compared to ventricular fibrillation with intermittent ischemia during coronary artery surgery. This suggests potential differences in myocardial protection strategies.
Area of Science:
- Cardiology
- Cardiac Surgery
- Biomarkers
Background:
- Myocardial management during cardiac surgery is crucial.
- Cold blood cardioplegia and ventricular fibrillation with intermittent ischemia are common strategies.
- Detecting myocardial damage requires sensitive markers.
Purpose of the Study:
- To compare myocardial damage between cold blood cardioplegia and ventricular fibrillation with intermittent ischemia.
- To evaluate the efficacy of creatine kinase MB isoforms and troponin T assays in detecting myocardial injury.
Main Methods:
- 40 patients undergoing elective coronary artery operations were randomized.
- Group 1 (n=20): Cold blood cardioplegia.
- Group 2 (n=20): Ventricular fibrillation with intermittent ischemia.
- Creatine kinase MB isoforms and troponin T levels were measured pre- and post-procedure (up to 48 hours).
Main Results:
- No significant differences in patient demographics or baseline left ventricular function.
- Median peak creatine kinase MB2 activity was significantly higher in the blood cardioplegia group (26.5 U/L vs. 19.5 U/L, p=0.04).
- Median peak troponin T concentration was higher in the blood cardioplegia group, but not significantly (2.2 ng/mL vs. 1.6 ng/mL, p=0.15).
Conclusions:
- Cold blood cardioplegia may be associated with greater myocardial release of creatine kinase MB2 compared to ventricular fibrillation with intermittent ischemia.
- Further research is needed to fully elucidate the clinical implications of these findings.
Abstract:
Despite the current trend for using blood cardioplegia, ventricular fibrillation with intermittent ischemia is still used as a strategy to manage the myocardium with impressive results. These two methods of myocardial management were compared in 40 patients undergoing elective coronary artery operations using creatine kinase MB isoforms and troponin T assays. Each patient was randomized to have either cold blood cardioplegia (n = 20) or ventricular fibrillation with intermittent ischemia (n = 20) for myocardial management during the construction of distal anastomoses. Until recently, the comparison of different methods of myocardial management has been hindered by the lack of a specific and sensitive marker of myocardial damage. Analysis of creatine kinase MB isoforms (MB2, cardiac tissue form; MB1, plasma-modified form) and cardiac-specific troponin T (a structural protein) has been shown to improve the sensitivity for the detection of myocardial damage. There were no significant differences between the two groups in age, sex ratio, extent of disease, or left ventricular function. Blood samples for analysis were collected before cross-clamp application and at time intervals up to 48 hours after. Median peak creatine kinase MB2 activity was found to be significantly higher in the blood cardioplegia group compared with ventricular fibrillation (26.5 U/L versus 19.5 U/L, respectively, p = 0.04). Although median peak troponin T concentration was higher in the blood cardioplegia group, the difference failed to reach significance (2.2 ng/mL versus 1.6 ng/mL, p = 0.15).(ABSTRACT TRUNCATED AT 250 WORDS)