Clinical testing of nicorandil supplemented normokalemic cardioplegic solution

Area of Science:

• Cardiology
• Cardiac Surgery
• Pharmacology

Background:

• Standard cardioplegic solutions utilize supranormal potassium for cardiac arrest.
• Nicorandil, a potassium channel activator, is explored as an alternative or adjunct.
• Assessing the safety and efficacy of nicorandil in human cardioprotection is crucial.

Purpose of the Study:

• To evaluate if nicorandil can safely replace supranormal potassium in cardioplegic solutions for cardioprotection during human cardiac surgery.
• To compare the time to cardiac arrest, rhythm abnormalities, and myocardial injury markers between nicorandil-containing and standard cardioplegic solutions.

Main Methods:

• A randomized study involving 50 patients undergoing coronary artery surgery.
• Two groups: one received standard St Thomas' Hospital solution (STHS), the other received a solution with nicorandil instead of supranormal potassium.
• Measurements included time to arrest, arrhythmias, troponin-T, CK-MB, myoglobin release, and hemodynamic parameters.

Main Results:

• Significantly longer time to cardiac arrest in the nicorandil group (120.9 s) compared to STHS group (41.0 s).
• Four patients in the nicorandil group required additional STHS for adequate cardiac arrest.
• Elevated troponin-T and myoglobin levels were observed in the nicorandil group post-surgery, indicating potential myocardial injury.

Conclusions:

• Nicorandil alone is likely insufficient to replace supranormal potassium in cardioplegic solutions for achieving rapid cardiac arrest.
• While hemodynamic performance was similar, early release of cardiac biomarkers in the nicorandil group suggests potential concerns for cardioprotection.
• Further research is needed to determine the optimal role, if any, of nicorandil in cardioplegic strategies.