Myocardial infarction related to valve replacement surgery

Area of Science:

• Cardiology
• Cardiac Surgery
• Diagnostic Imaging

Background:

• Myocardial infarction (MI) is a potential complication following cardiac valve replacement surgery.
• Accurate and timely diagnosis of MI is crucial for patient outcomes.
• Various diagnostic methods exist, but their efficacy in the context of valve replacement surgery requires clarification.

Purpose of the Study:

• To determine the incidence of preoperative myocardial infarction in patients undergoing aortic and mitral valve replacement.
• To evaluate the diagnostic accuracy of different methods for detecting myocardial infarction in this patient population.

Main Methods:

• Prospective study of 50 consecutive patients (25 aortic valve replacement, 25 mitral valve replacement).
• Serial electrocardiography, technetium-99m pyrophosphate radionuclide scanning, and serial enzyme measurements (creatine kinase, aspartate aminotransferase, lactic dehydrogenase, creatine kinase MB isoenzyme).

Main Results:

• Myocardial scanning and peak enzyme activity were accurate indicators of myocardial infarction.
• Electrocardiography showed limited diagnostic value.
• Creatine kinase MB isoenzyme offered no diagnostic advantage over other enzyme tests.
• Incidence of non-fatal MI was 16% after aortic valve replacement and 4% after mitral valve replacement.

Conclusions:

• Technetium-99m pyrophosphate myocardial scanning and peak enzyme activity are reliable diagnostic tools for MI post-valve replacement.
• Routine ECG and CK-MB isoenzyme measurements are less valuable for diagnosing MI in this setting.
• Mitral valve replacement was associated with a lower incidence of MI compared to aortic valve replacement.