Comparison of the Effect of N-Acetylcysteine and Vitamin C Supplementation of Cardioplegic Solution on Changes in Postoperative Serum Cardiac Troponin Levels Following On-Pump Coronary Artery Bypass Grafting

To determine and compare the effects of adding N-acetylcysteine and vitamin C to cardioplegic solution on postoperative serum cardiac troponin levels in patients undergoing on-pump coronary artery bypass grafting.

Randomized, double-blind, parallel-group clinical trial using block randomization, conducted among 70 patients scheduled for on-pump coronary artery bypass grafting (CABG).

Patients scheduled for on-pump coronary artery bypass grafting (CABG) at Amir al-Momenin Hospital in Arak will be screened based on predefined eligibility criteria and allocated into two intervention groups (A and B) using web-based block randomization. In this double-blind trial, the patients, perfusionists, and cardiac surgeon will remain blinded to the assigned treatments.

Inclusion Criteria: Patients aged 30–75 years who are candidates for on-pump coronary artery bypass grafting (CABG), have no history of previous cerebrovascular events, and present with written informed consent. Exclusion Criteria: Concomitant cardiac valve repair or replacement during CABG, prolongation of operative duration beyond 6 hours, and requirement for reinstitution of cardiopulmonary bypass during surgery.

Patients in Group A and Group B will receive 50 mg/kg of Vitamin C (Alborz Pharmaceutical) and N-acetylcysteine (Exir Pharmaceutical), respectively, added to the cardioplegic solution during the procedure.

For each patient in Groups A and B, serum cardiac troponin (cTn) levels will be measured using quantitative troponin assay kits before surgery and at 24 and 48 hours after open-heart surgery. The results will be recorded and analyzed. In addition, the percentage changes in serum cardiac troponin levels at the specified time points will be compared between the intervention groups.

Randomization Method: Block randomization Unit of Randomization: Individual participant Description of Randomization Procedure: Given the planned sample size, permuted blocks of four participants will be used. Group 1 will receive vitamin C added to the cardioplegic solution (Group A), whereas Group 2 will receive N-acetylcysteine added to the cardioplegic solution (Group B). For each block of four participants, the six possible allocation sequences are: AABB, BBAA, ABAB, BABA, ABBA, BAAB. One sequence will be selected at random for each block. Before participant enrollment begins, a random allocation list corresponding to the total required sample size will be generated based on these randomly selected block sequences. Randomization Tool and Allocation Concealment: A web-based randomization program will be used to generate the allocation sequence. The program will create randomly permuted treatment assignments for both study groups within each block. Because the order of treatment allocations varies randomly across blocks, allocation concealment will be maintained and the investigator’s ability to predict the treatment assignment of subsequent participants during the study will be minimized. Web-based tool used for random permuted-block allocation: https://www.sealedenvelope.com/simple-randomiser/v1/lists

In this study, the two investigational agents will be prepared by an anesthesiologist in identical syringes of the same color, size, and appearance, according to each patient’s clinical condition. The syringes will be labeled using coded identifiers and provided to the cardiopulmonary bypass (CPB) team for administration. Patients receiving vitamin C added to the cardioplegic solution will be assigned to Group A, while those receiving N-acetylcysteine added to the cardioplegic solution will be assigned to Group B. The patients and the perfusionists responsible for operating the cardiopulmonary bypass machine will remain unaware of the study-group assignments and the contents of the syringes. Only the anesthesiologist, through the syringe coding system, will be aware of the allocated intervention. Furthermore, the cardiac surgeon will be blinded to the treatment allocation and the identity of the administered investigational agent throughout the surgical procedure. Therefore, because the patients, perfusionists, and cardiac surgeon are blinded to the intervention, the study will be conducted as a double-blind clinical trial.