Effect of the Addition of Adenosine on Myocardial Protection During Cardiopulmonary Bypass

The goal of this clinical trial is to evaluate whether the addition of adenosine to standard cardioplegia improves myocardial protection in adult patients undergoing on-pump cardiac surgery. The study population includes adult patients of both sexes undergoing elective cardiac procedures requiring cardiopulmonary bypass and cardioplegic arrest. The main questions this trial aims to answer are: Does the addition of adenosine to cardioplegia affect myocardial protection as assessed by transesophageal echocardiography (TEE)? What is the effect of adenosine on biochemical markers of myocardial injury, such as postoperative high-sensitivity troponin levels? What is the effect of adenosine on perioperative hemodynamic support requirements, as quantified by the Vasoactive-Inotropic Score (VIS)? Researchers will compare patients receiving adenosine-supplemented cardioplegia with those receiving standard cardioplegia (placebo) to assess differences in echocardiographic indicators of myocardial protection, biomarker release, and need for vasoactive/inotropic support. Participants will: Receive either adenosine-supplemented cardioplegia (adenosine 1.2 mmol/L; 24 mg) or placebo according to randomization. Undergo standard perioperative monitoring during cardiac surgery. Undergo intraoperative transesophageal echocardiography (TEE) to evaluate myocardial protection by comparing pre- and post-cardiopulmonary bypass (CPB) measurements. Have postoperative laboratory testing for high-sensitivity troponin at baseline, 2h, 12h, and 24h after clamp release. Have hemodynamic support requirements recorded and VIS calculated at the end of surgery and at 12h and 24h postoperatively. Be followed for perioperative clinical outcomes including arrhythmias, need for cardioversion or mechanical circulatory support, ICU/hospital length of stay, myocardial infarction, and mortality.