Optimal myocardial protection

Area of Science:

• Cardiovascular Surgery
• Cardiac Anesthesia
• Myocardial Protection

Background:

• Aortocoronary bypass (ACB) surgery requires effective myocardial protection strategies.
• Low perioperative infarction rates make it challenging to evaluate myocardial protection methods.
• Enzymatic and functional measurements are sensitive indicators of myocardial injury.

Purpose of the Study:

• To evaluate the effectiveness of three myocardial protection methods during triple ACB.
• To compare cold potassium cardioplegia (single vs. multiple doses) and intermittent anoxic arrest.

Main Methods:

• Prospective concurrent study of 78 patients undergoing triple ACB.
• Group I: Single cold (4°C) potassium cardioplegic solution (PCS) (n=32).
• Group II: Multiple doses of PCS (n=23).
• Group III: Intermittent anoxic arrest (n=23).
• Measured myocardial temperature (MMT), cardiac-specific creatine kinase (CK-MB), left ventricular stroke work index (SW), and left atrial pressure (LAP).

Main Results:

• Group II achieved a significantly lower MMT (22±2°C) compared to Group I (31±4°C) and Group III (28±1°C).
• Peak CK-MB levels were significantly lower in Group II (25±8 IU/L) than Group I (50±8 IU/L) and Group III (68±14 IU/L).
• The rise and peak SW were significantly greater in Group II at comparable LAP values, indicating superior myocardial performance.

Conclusions:

• Cold, multidose cardioplegia provides superior myocardial protection during ACB.
• Enzymatic (CK-MB) and functional (SW, LAP) measurements are more sensitive than clinical evaluation for assessing myocardial protection.
• Multidose cold cardioplegia is recommended for optimal myocardial protection in ACB procedures.