(1778) Beyond the Scalpel: Preventing Renal Failure in Cardiac Surgery Patients Using Urinary Biomarkers

Introduction: Acute kidney injury (AKI) following cardiothoracic surgery is a common complication that increases mortality and hospital length of stay. Urinary biomarkers can be used to identify high risk patients following cardiothoracic surgery, allowing for implementation of preventive measures to reduce the risk of AKI. The goal of this study is to describe urinary biomarker results and identify opportunities for improvement in the post-operative management of cardiothoracic surgery patients.

Methods: This single-center, retrospective observational study conducted at Ascension St. John Hospital in Detroit, Michigan. Adult patients will be included if they received surgery with the use of cardiopulmonary bypass. Patients will be excluded if they received dialysis preoperatively, had a pre-operative serum creatinine greater than 4 mg/dL, or urine biomarkers (NephroCheck®) were not sent. A random sample of one hundred patients with a moderate (NephroCheck 0.3-0.7) or high risk (NephroCheck > 0.7) of AKI, defined as urinary biomarker [TIMP-2] x [IGFBP7] of > 0.3, will be evaluated from between August 30, 2021 and August 30, 2023. AKI will be defined using the KDIGO guidelines and will be assessed during the postoperative course.

Results: This study evaluated 249 patients. Urinary biomarkers indicated that 28% of patients were at moderate-risk and 12% were at high-risk of developing moderate to severe AKI. AKI occurred in 30% of the moderate-risk group and 50% of the high-risk group. The receipt of nephrotoxic medications was prevalent among moderate (59%, AKI 10%) and high (67%, AKI 27%) risk patients, with ketorolac (85.2%) identified as the most frequently prescribed offender. Opportunities to optimize volume management were present on POD #1 in 60% of patients (AKI 32%) and POD #2 in 53% of patients (AKI 26%). Episodes of hypotension (MAP < 65 mmHg) occured in 36% of moderate (AKI 14%) and 37% of high (23% AKI) risk patients. Hypoperfusion (CI < 2.2 L/min/m2) occured in 10% of moderate (AKI 6%) and 37% of high (27% AKI) risk patients.

Conclusions: Early identification of at-risk cardiothoracic surgery patients is crucial for preventing AKI. Opportunities exist to optimize post-operative care for patients identified as moderate or high risk of developing AKI using urinary biomarkers.