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Myocardial infarction related to coronary artery bypass graft surgery
Insights
This study found that myocardial scanning and enzyme levels effectively diagnose perioperative myocardial infarction after coronary artery bypass grafting. Electrocardiography was less reliable for detecting this complication.
Area of Science:
- Cardiology
- Cardiac Surgery
- Diagnostic Imaging
Background:
- Coronary artery bypass grafting (CABG) is a common procedure for chronic stable angina.
- Accurate diagnosis of perioperative myocardial infarction (PMI) is crucial for patient outcomes.
- Identifying optimal diagnostic methods for PMI remains an area of clinical interest.
Purpose of the Study:
- To assess the incidence of perioperative myocardial infarction in patients undergoing CABG.
- To identify the most appropriate diagnostic techniques for perioperative myocardial infarction.
- To evaluate the impact of perioperative myocardial infarction on cardiac function.
Main Methods:
- Serial electrocardiography.
- Preoperative and postoperative myocardial scanning with technetium-99m pyrophosphate.
- Gated radionuclide ventriculography.
- Serial measurement of cardiac enzymes (creatine kinase, aspartate aminotransferase, lactic dehydrogenase) and creatine kinase isoenzyme (MB).
Main Results:
- The correlation between myocardial scanning and peak enzyme/isoenzyme activity was excellent for diagnosing perioperative infarction.
- Electrocardiography was less helpful in diagnosing perioperative infarction.
- There was no significant advantage in measuring creatine kinase MB isoenzyme compared to routine cardiac enzymes.
- The incidence of perioperative infarction was 14% (7 out of 50 patients), with 2 deaths.
- Perioperative infarction was associated with a significant reduction in resting ejection fraction in two cases.
Conclusions:
- Myocardial scanning and cardiac enzyme measurements are reliable for diagnosing perioperative myocardial infarction after CABG.
- Routine cardiac enzymes are sufficient; creatine kinase MB isoenzyme offers no additional diagnostic benefit.
- Perioperative myocardial infarction negatively impacts cardiac function, evidenced by reduced ejection fraction.
Abstract:
Fifty consecutive patients undergoing coronary artery bypass grafting for chronic stable angina were assessed by serial electrocardiography, preoperative and postoperative myocardial scanning with technetium-99m pyrophosphate, gated radionuclide ventriculography, and serial measurement of creatine kinase, aspartate aminotransferase, urea stable lactic dehydrogenase, and creatine kinase isoenzyme (MB) to assess the incidence of perioperative myocardial infarction and identify the most appropriate diagnostic techniques. The correlation between myocardial scanning and the measurement of peak enzyme and isoenzyme activity was excellent in the diagnosis of perioperative infarction, although electrocardiography proved less helpful. There appeared to be no advantage in measuring creatine kinase MB rather than the more routinely measured enzymes. There were two deaths and evidence of myocardial infarction in five other patients, an incidence of 14%. Perioperative infarction was associated with a significant reduction in resting ejection fraction in two cases. In those patients without evidence of perioperative infarction the mean increase in ejection fraction of 7.8% was statistically significant.