The optimal potassium concentration in cardioplegic solutions

Area of Science:

• Cardiology
• Biochemistry

Background:

• High-energy phosphates, such as adenosine triphosphate (ATP), are critical indicators of heart muscle health.
• Effective myocardial preservation during cardiac surgery is essential for patient outcomes.

Purpose of the Study:

• To evaluate the impact of varying potassium concentrations in crystalloid cardioplegic solutions on myocardial protection.
• To determine the optimal potassium level for preserving high-energy phosphates during hypothermic ischemic arrest and reperfusion.

Main Methods:

• An in vivo pig-heart model was employed to simulate cardiac arrest.
• Left ventricular adenosine triphosphate (ATP) levels were measured before, during, and after a 2-hour ischemic period, followed by 30 minutes of reperfusion.
• Thirty-eight animals were divided into seven groups, each receiving a different potassium concentration (5, 10, 15, 20, 25, 30, 35 mEq/L) in the cardioplegic solution.

Main Results:

• The highest preservation of ATP was observed in the group treated with 15 mEq/L potassium.
• Significantly lower ATP levels were recorded in the 5 mEq/L potassium group.
• Intermediate ATP preservation was noted in groups receiving 10, 20, 25, 30, and 35 mEq/L potassium concentrations.

Conclusions:

• Cardioplegic solutions with 5 mEq/L potassium are insufficient for adequate myocardial protection during ischemic arrest.
• A potassium concentration of 15 mEq/L appears to provide the most effective myocardial protection among the tested levels.
• Potassium concentrations of 15 mEq/L and 35 mEq/L demonstrated superior myocardial protection compared to normokalemic (5 mEq/L) solutions.