The 2 groups had some mismatched variables, including patients older than 75 years, patients with higher EuroSCORE (>5), presence of cancer, chronic kidney disease, or lower preoperative hemoglobin (<10 g/dL), preoperative usage of angiotensin receptor blocker and angiotensin converting enzyme inhibitor, and duration of surgery before propensity score matching (standardized differences >10%). The gene discussed is ACE; the disease is chronic kidney disease.