Cardioplegias are different pharmacokinetic solutions routinely used in cardiac surgery to protect the heart from ischemia and induce arrest. Various cardioplegia solutions (such as Bretschneider, del Nido, blood cardioplegia, crystalloid cardioplegia, St. Thomas) are used in clinical practice. There is no clear scientific data in the literature that demonstrates the superiority of one cardioplegia over the others. The choice of the appropriate cardioplegia depends on the surgeon's clinical experience and preference. In this study preferred the blood cardioplegia and del Nido cardioplegia, which are commonly used in clinic. Both cardioplegias have different advantages that contribute to their preference in clinical practice.

Blood cardioplegia is an autologous cardioplegia that includes physiological buffer systems, allowing for heart nourishment and containing native antioxidant systems. However, the need for repeated doses every 20 minutes after the initial application creates a disadvantage in terms of surgical comfort. On the other hand, del Nido cardioplegia is preferred by surgeons in complex cases due to its long application intervals. The adequacy of a single dose for up to 90 minutes after the initial application creates an advantage in terms of surgical comfort and surgical integrity. However, the content being predominantly electrolyte-based, containing 1:4 ratio of autologous blood, and the extended time of a single dose are disadvantages compared to blood cardioplegia in terms of heart nourishment and protection from ischemia. In addition to these different usage scenarios, the myocardial protective effects of cardioplegias on cellular redox homeostasis are also among the current research topics. Thesis project can contribute to the current literature and clinical practice on the cardioprotective advantages of cardioplegia solutions and the reasons for their preference in surgery.

Cardioplegias are routinely used in cardiac surgery to protect the heart from ischemia. Choice of the cardioplegia depends on surgeons clinical experience and preference. Various cardioplegia solutions (such as Bretschneider, del Nido, blood cardioplegia, crystalloid cardioplegia, St. Thomas) are widely used in clinical practice. There is no clear scientific data in the current literature that demonstrates the superiority of one cardioplegia over the others.

In this study preferred the blood and del Nido cardioplegia solutions, which are commonly used in clinic. Blood cardioplegia is an autologous cardioplegia that includes physiological buffer systems, allowing for heart nourishment and containing native antioxidant systems. However, the need for repeated doses every 20 minutes after the initial application creates a disadvantage in terms of surgical comfort. On the other hand, del Nido cardioplegia is preferred by surgeons in complex cases due to its long application intervals.

The adequacy of a single dose for up to 90 minutes after the initial application creates an advantage in terms of surgical comfort and surgical integrity. However, the content being predominantly electrolyte-based, containing 1:4 ratio of autologous blood, and the extended time of a single dose are disadvantages compared to blood cardioplegia in terms of heart nourishment and protection from ischemia. Hamad et al reported that del Nido and blood cardioplegia solutions offer equivalent safety in combined adult valve surgery. In addition to these differences, the myocardial protective effects of cardioplegias on myocardial redox homeostasis are also among the current research topics. Ischemia and reperfusion injury can be observed in the myocardial tissues of patients undergoing coronary artery bypass graft surgery and isolated valve replacement surgery. It was reported that coronary sinus blood sampling gives an insight into the localized pathophysiology of heart diseases. Comparative research examining the effects of blood and del Nido cardioplegia solutions on coronary sinus redox status is not currently available in the literature. The study aim to contribute to the development of effective strategies to minimize oxidative damage associated with cardiac surgery by investigating the effects of blood and del Nido cardioplegia solutions on coronary sinus redox homeostasis during the preoperative and postoperative periods using redox biomarkers and antioxidant system transcription factors. Thesis project also intend to compare these redox effects with elective isolated valve replacement surgery patients, who do not have coronary artery disease but share a similar pathogenesis with potential strategies for minimizing oxidative damage associated with cardiac surgery using cardiopulmonary bypass (CPB).

Inclusion Criteria:

• Patients who underwent elective coronary artery bypass surgery due to coronary artery disease
• Patients without coronary artery disease who underwent elective valve surgery
• Patients between the ages of 18-75
• Having a BMI of 18.5-30

Exclusion Criteria:

• Being under 18 years old
• Patients older than 75 years
• Patients requiring valve surgery (combined surgical procedure) with coronary artery bypass
• Patients who underwent emergency coronary bypass
• BMI > 30 obese patients

Patients, Dr. Siyami Ersek Thoracic and Cardiovascular Surgery Training and Research Hospital, Adult Cardiovascular Surgery Clinic will be selected among the patients who will undergo cardiac surgery and meet the inclusion criteria.

During the process of obtaining informed consent from the participants involved in the study, it was stated that their data would not be used elsewhere.