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Myosin: a highly sensitive indicator of myocardial necrosis after cardiac operations
J R Séguin1, M Saussine, M Ferrière
1Thoracic and Cardiovascular Surgery, C.H.U. Hôpital Saint Eloi, Montpellier, France.
Abstract:
Plasma levels of ventricular myosin fragments, determined with monoclonal antibodies to myosin heavy chains, were studied in 27 patients after cardiac operations (17 aorta-coronary bypass grafts and 10 valve replacements) to assess their possible role as a marker of perioperative myocardial necrosis. Five patients had perioperative myocardial necrosis after aorta-coronary bypass grafts as indicated by changes in the electrocardiogram and elevated levels of the MB isoenzyme of creatine kinase. Six more patients were also studied after thoracic operations performed by the same sternotomy approach. After cardiac operations, myosin levels increased from postoperative day 3 and reached peak values on day 7. Peak myosin values in patients with perioperative myocardial necrosis after aorta-coronary bypass grafting were significantly higher than in patients after an identical operation but without perioperative myocardial infarction (3793 +/- 592 versus 369 +/- 47 ng/ml; p less than 0.001). These results suggest that plasma myosin is a sensitive marker of myocardial necrosis. Furthermore, peak plasma levels of ventricular myosin after coronary bypass grafting without myocardial infarction (mean value 369 +/- 47 ng/ml) were not significantly different from peak levels after thoracic operations (mean value 253 +/- 52 ng/ml), whereas they were significantly higher after valve replacement (mean value 794 +/- 149 ng/ml; p less than 0.01). These results indicate that a certain degree of myocardial necrosis occurs during value replacement that is undetectable by the usual diagnostic criteria for perioperative myocardial infarction. We conclude that the plasma level of ventricular myosin fragments is a more specific and accurate marker of perioperative myocardial necrosis than changes in the electrocardiogram or elevated creatine kinase MB levels. Therefore the detection of myosin fragments, which appear in the serum on the third day after cardiac operations, may be useful for precise comparisons of different techniques of myocardial protection.
Insights
Plasma levels of ventricular myosin fragments are a sensitive marker for perioperative myocardial necrosis after cardiac surgery. Myosin levels accurately detect myocardial damage undetectable by traditional methods, aiding in comparing surgical techniques.
Area of Science:
- Cardiology
- Biomarkers
- Cardiac Surgery
Background:
- Assessing perioperative myocardial necrosis is crucial for patient outcomes.
- Current markers like ECG and creatine kinase MB have limitations.
Purpose of the Study:
- To evaluate plasma ventricular myosin fragments as a sensitive and specific marker of perioperative myocardial necrosis.
- To compare myosin levels with traditional markers after cardiac operations.
Main Methods:
- Monoclonal antibodies were used to measure plasma ventricular myosin fragments.
- Levels were studied in 27 patients undergoing cardiac operations (CABG, valve replacement) and 6 thoracic surgery patients.
- Myosin levels were correlated with ECG and CK-MB findings.
Main Results:
- Plasma myosin levels increased post-operation, peaking on day 7.
- Patients with myocardial necrosis after CABG had significantly higher peak myosin levels.
- Ventricular myosin levels after valve replacement were higher than after CABG without necrosis, suggesting subclinical damage.
Conclusions:
- Plasma ventricular myosin fragments are a sensitive and specific marker for perioperative myocardial necrosis.
- Myosin detection can identify myocardial necrosis missed by conventional methods.
- This marker aids in comparing myocardial protection strategies in cardiac surgery.