Trajectory-Based Phenotyping After Coronary Artery Bypass Surgery

Coronary artery bypass grafting is a commonly performed heart surgery, but patients may have different risks for postoperative complications even when their preoperative risk scores are similar. EuroSCORE II is widely used to estimate surgical risk before cardiac surgery, but it may not fully reflect how the body responds during the early postoperative period. This retrospective observational study will evaluate adult patients who underwent elective coronary artery bypass grafting with cardiopulmonary bypass between January 1, 2022 and December 31, 2025. The study will use existing hospital records and laboratory data. No additional treatment, test, or intervention will be given to patients as part of this study. The main aim is to examine whether early postoperative changes in inflammatory and renal laboratory markers can identify different patient subgroups, called phenotypes. These markers include neutrophil-to-lymphocyte ratio, systemic immune-inflammation index, triglyceride-glucose index, and serum creatinine. The study will evaluate whether these phenotype groups are associated with postoperative acute kidney injury and prolonged intensive care unit stay. The study will also assess whether this early postoperative phenotype-based classification provides additional risk information beyond EuroSCORE II.